WorldWideScience

Sample records for two-element wide-angle telescope

  1. Wide-angle cherenkov telescope prototype preliminary data

    Science.gov (United States)

    Timofeev, Lev; Anatoly, Ivanov

    2016-07-01

    This report presents an observation method of Cherenkov light from extensive air showers (EAS) generated by cosmic rays (CRs) above 10^16eV and preliminary observations. The interest in Cherenkov light differential detectors of EAS is caused by the possibility to measure the depth of cascade maximum, Xmax, and/or the shower age via angular and temporal distributions of the Cherenkov signal. In particular, it was shown using EAS model simulations that the pulse width measured at the periphery of the shower, r > 300 m, at sea level is pronouncedly connected with Xmax. Cherenkov detector is a wide-angle telescope working in coincidence with scintillation detectors, integral and differential Cherenkov detectors Yakutsk complex EAS.

  2. Wide-angle vision for road views

    Science.gov (United States)

    Huang, F.; Fehrs, K.-K.; Hartmann, G.; Klette, R.

    2013-03-01

    The field-of-view of a wide-angle image is greater than (say) 90 degrees, and so contains more information than available in a standard image. A wide field-of-view is more advantageous than standard input for understanding the geometry of 3D scenes, and for estimating the poses of panoramic sensors within such scenes. Thus, wide-angle imaging sensors and methodologies are commonly used in various road-safety, street surveillance, street virtual touring, or street 3D modelling applications. The paper reviews related wide-angle vision technologies by focusing on mathematical issues rather than on hardware.

  3. QUEST: wide angle Cherenkov light measurements at EAS-TOP

    Science.gov (United States)

    EAS-Top Collaboration; Korosteleva, E. E.; Kuzmichev, L. A.; Prosin, V. V.; Lubsandorzhiev, B. K.

    Wide angle Cherenkov light detectors based upon the QUASAR-370 photo-multipliers have been installed on five Cherenkov telescopes of the EAS-TOP array to study the energy spectrum and composition of primary cosmic rays around the knee . The energy threshold of quasars array was close to that of EAS-TOP electromagnetic detectors array. The first results of joint analysis of Cherenkov and electromagnetic data together with the adequate CORSIKA simulation results are discussed.

  4. ATLAS, and Wide-Angle Tail Galaxies in ATLAS

    Indian Academy of Sciences (India)

    Minnie Y. Mao; Rob Sharp; D. J. Saikia; Ray P. Norris; Melanie Johnston-Hollitt; Enno Middelberg; Jim E. J. Lovell

    2011-12-01

    Using the Australia Telescope Compact Array (ATCA), ATLAS (Australia Telescope Large Area Survey) is imaging two fields totalling 7 square degrees down to 10 Jy beam-1 at 1.4 GHz. We have found 6 wide-angle tail galaxies (WATs), 4 of which have sufficient data to identify associated galaxy overdensities. The largest WAT, at a red-shift of 0.22, appears to be associated with an overdensity of galaxies that is spread over an unusually large extent of 12Mpc, with a velocity range of 4500 km s-1. Here we present the WATs in ATLAS and discuss the implications of these observations for future large-scale radio surveys such as ASKAP-EMU.

  5. Wide Angle Effects in Galaxy Surveys

    CERN Document Server

    Yoo, Jaiyul

    2013-01-01

    Current and future galaxy surveys cover a large fraction of the entire sky with a significant redshift range, and the recent theoretical development shows that general relativistic effects are present in galaxy clustering on very large scales. This trend has renewed interest in the wide angle effect in galaxy clustering measurements, in which the distant-observer approximation is often adopted. Using the full wide-angle formula for computing the redshift-space correlation function, we show that compared to the sample variance, the deviation in the redshift-space correlation function from the simple Kaiser formula with the distant-observer approximation is negligible in the SDSS and is completely irrelevant in future galaxy surveys such as Euclid and the BigBOSS, if the theoretical prediction from the Kaiser formula is averaged over the survey volume and the non-uniform distribution of cosine angle between the line-of-sight and the pair separation directions is properly considered. We also find small correctio...

  6. Wide Angle Michelson Doppler Imaging Interferometer (WAMDII)

    Science.gov (United States)

    Roberts, B.

    1986-01-01

    The wide angle Michelson Doppler imaging interferometer (WAMDII) is a specialized type of optical Michelson interferometer working at sufficiently long path difference to measure Doppler shifts and to infer Doppler line widths of naturally occurring upper atmospheric Gaussian line emissions. The instrument is intended to measure vertical profiles of atmospheric winds and temperatures within the altitude range of 85 km to 300 km. The WAMDII consists of a Michelson interferometer followed by a camera lens and an 85 x 106 charge coupled device photodiode array. Narrow band filters in a filter wheel are used to isolate individual line emissions and the lens forms an image of the emitting region on the charge coupled device array.

  7. Wide-angle energy-momentum spectroscopy

    CERN Document Server

    Dodson, Christopher M; Li, Dongfang; Zia, Rashid

    2014-01-01

    Light emission is defined by its distribution in energy, momentum, and polarization. Here, we demonstrate a method that resolves these distributions by means of wide-angle energy-momentum spectroscopy. Specifically, we image the back focal plane of a microscope objective through a Wollaston prism to obtain polarized Fourier-space momentum distributions, and disperse these two-dimensional radiation patterns through an imaging spectrograph without an entrance slit. The resulting measurements represent a convolution of individual radiation patterns at adjacent wavelengths, which can be readily deconvolved using any well-defined basis for light emission. As an illustrative example, we use this technique with the multipole basis to quantify the intrinsic emission rates for electric and magnetic dipole transitions in europium-doped yttrium oxide (Eu$^{3+}$:Y$_{2}$O$_{3}$) and chromium-doped magnesium oxide (Cr$^{3+}$:MgO). Once extracted, these rates allow us to reconstruct the full, polarized, two-dimensional radi...

  8. Generalized parton distributions and wide-angle exclusive scattering

    CERN Document Server

    Kroll, P

    2004-01-01

    The handbag mechanism for wide-angle exlusive scattering reactions is discussed and compared with other theoretical approaches. Its application to Compton scattering, meson photoproduction and two-photon annihilations into pairs of hadrons is reviewed.

  9. Lightweight autoclavable wide-angle contact lens for vitreous surgery.

    Science.gov (United States)

    Chalam, K V; Gupta, Shailesh K; Agarwal, Swati

    2007-01-01

    The authors describe an autoclavable, self-stabilizing, lightweight wide-angle contact lens for vitrectomy. The lens has two optical pieces with perforated plastic casing to sustain a high temperature (150 degrees C) for autoclaving. The lens has a 106 degrees static and 127 degrees dynamic field of view. The footplates and reduced weight (2.4 grams) due to the plastic casing allow self-stabilization of the lens. The open lens design.with high temperature resistant plastic prevents fogging during autoclaving and surgery. The autoclavable, self-stabilizing, lightweight wide-angle contact lens allows visualization of the peripheral retina during surgery and faster sterilization by autoclaving between surgeries without the disadvantage of lens fogging.

  10. Large-area, wide-angle, spectrally selective plasmonic absorber

    CERN Document Server

    Wu, Chihhui; John, Jeremy; Milder, Andrew; Zollars, Byron; Savoy, Steve; Shvets, Gennady

    2011-01-01

    A simple metamaterial-based wide-angle plasmonic absorber is introduced, fabricated, and experimentally characterized using angle-resolved infrared spectroscopy. The metamaterials are prepared by nano-imprint lithography, an attractive low-cost technology for making large-area samples. The matching of the metamaterial's impedance to that of vacuum is responsible for the observed spectrally selective "perfect" absorption of infrared light. The impedance is theoretically calculated in the single-resonance approximation, and the responsible resonance is identified as a short-range surface plasmon. The spectral position of the absorption peak (which is as high as 95%) is experimentally shown to be controlled by the metamaterial's dimensions. The persistence of "perfect" absorption with variable metamaterial parameters is theoretically explained. The wide-angle nature of the absorber can be utilized for sub-diffraction-scale infrared pixels exhibiting spectrally selective absorption/emissivity.

  11. SuperWASP Wide Angle Search for Planets

    CERN Document Server

    Street, R A; Fitzsimmons, A; Keenan, F P; Horne, K; Kane, S; Cameron, A C; Lister, T A; Haswell, C; Norton, A J; Jones, B W; Skillen, I; Hodgkin, S T; Wheatley, P; West, R; Brett, D; Horne, Keith

    2002-01-01

    SuperWASP is a fully robotic, ultra-wide angle survey for planetary transits. Currently under construction, it will consist of 5 cameras, each monitoring a 9.5 x 9.5 deg field of view. The Torus mount and enclosure will be fully automated and linked to a built-in weather station. We aim to begin observations at the beginning of 2003.

  12. Automatic Traffic Monitoring from an Airborne Wide Angle Camera System

    OpenAIRE

    Rosenbaum, Dominik; Charmette, Baptiste; Kurz, Franz; Suri, Sahil; Thomas, Ulrike; Reinartz, Peter

    2008-01-01

    We present an automatic traffic monitoring approach using data of an airborne wide angle camera system. This camera, namely the “3K-Camera”, was recently developed at the German Aerospace Center (DLR). It has a coverage of 8 km perpendicular to the flight direction at a flight height of 3000 m with a resolution of 45 cm and is capable to take images at a frame rate of up to 3 fps. Based on georeferenced images obtained from this camera system, a near real-time processing chain containing roa...

  13. Group sparsity based airborne wide angle SAR imaging

    Science.gov (United States)

    Wei, Zhonghao; Zhang, Bingchen; Bi, Hui; Lin, Yun; Wu, Yirong

    2016-10-01

    In this paper, we develop a group sparsity based wide angle synthetic aperture radar (WASAR) imaging model and propose a novel algorithm called backprojection based group complex approximate message passing (GCAMP-BP) to recover the anisotropic scene. Compare to conventional backprojection based complex approximate message passing (CAMP-BP) algorithm for the recovery of isotropic scene, the proposed method accommodates aspect dependent scattering behavior better and can produce better imagery. Simulated and experimental results are presented to demonstrate the validity of the proposed algorithm.

  14. Wide-angle spectrometer at intersection I-2

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    The members of the British-Scandinavian ISR Collaboration "manning the rails" of the wide-angle spectrometer at intersection I-2, whose vacuum chamber is visible to theleft. The equipment of this high-momentum version of experiment R203 consists of scintillation counter hodoscopes, wire spark chambers, and spherical high-pressure threshold Cerenkov counters before and after an analysing magnet. The equipment is mounted on a movable platform. The smaller magnet suspended above the spectrometer measures the momentum of cosmic rays.

  15. Performance measurement of broadband, wide-angle polarizing beam splitter

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei-bin; ZHENG Zhen-rong; GU Pei-fu; ZHANG Yue-guang

    2007-01-01

    Polarizing beam splitter (PBS) is a critical optical component in projection display system because PBS performance greatly influences the contrast and brightness of the system. PBS performance is usually measured by spectrophotometer after coating and cementing, but the measured result cannot represent the actual performance in practice because people usually change the incident angle in one plane (horizontal plane) and do not consider the other plane (vertical plane). Geometrical polarization rotation occurring at reduced F-number influences the measuring precision of s-polarization transmittance (Ts) and p-polarization reflectance (Rp). A more accurate and practical way to measure the performance of broadband, wide-angle PBS is presented in this paper.

  16. Honeywell's Compact, Wide-angle Uv-visible Imaging Sensor

    Science.gov (United States)

    Pledger, D.; Billing-Ross, J.

    1993-01-01

    Honeywell is currently developing the Earth Reference Attitude Determination System (ERADS). ERADS determines attitude by imaging the entire Earth's limb and a ring of the adjacent star field in the 2800-3000 A band of the ultraviolet. This is achieved through the use of a highly nonconventional optical system, an intensifier tube, and a mega-element CCD array. The optics image a 30 degree region in the center of the field, and an outer region typically from 128 to 148 degrees, which can be adjusted up to 180 degrees. Because of the design employed, the illumination at the outer edge of the field is only some 15 percent below that at the center, in contrast to the drastic rolloffs encountered in conventional wide-angle sensors. The outer diameter of the sensor is only 3 in; the volume and weight of the entire system, including processor, are 1000 cc and 6 kg, respectively.

  17. A wide-angle camera module for disposable endoscopy

    Science.gov (United States)

    Shim, Dongha; Yeon, Jesun; Yi, Jason; Park, Jongwon; Park, Soo Nam; Lee, Nanhee

    2016-08-01

    A wide-angle miniaturized camera module for disposable endoscope is demonstrated in this paper. A lens module with 150° angle of view (AOV) is designed and manufactured. All plastic injection-molded lenses and a commercial CMOS image sensor are employed to reduce the manufacturing cost. The image sensor and LED illumination unit are assembled with a lens module. The camera module does not include a camera processor to further reduce its size and cost. The size of the camera module is 5.5 × 5.5 × 22.3 mm3. The diagonal field of view (FOV) of the camera module is measured to be 110°. A prototype of a disposable endoscope is implemented to perform a pre-clinical animal testing. The esophagus of an adult beagle dog is observed. These results demonstrate the feasibility of a cost-effective and high-performance camera module for disposable endoscopy.

  18. WAMDII: The Wide Angle Michelson Doppler Imaging Interferometer

    Science.gov (United States)

    1992-01-01

    As part of an effort to learn more about the upper atmosphere and how it is linked to the weather experienced each day, NASA and NRCC are jointly sponsoring the Wide Angle Michelson Doppler Imaging Interferometer (WAMDII) Mission. WAMDII will measure atmospheric temperature and wind speed in the upper atmosphere. In addition to providing data on the upper atmosphere, the wind speed and temperature readings WAMDII takes will also be highly useful in developing and updating computer simulated models of the upper atmosphere. These models are used in the design and testing of equipment and software for Shuttles, satellites, and reentry vehicles. In making its wind speed and temperature measurements, WAMDII examines the Earth's airglow, a faint photochemical luminescence caused by the influx of solar ultraviolet energy into the upper atmosphere. During periods of high solar flare activity, the amount of this UV energy entering the upper atmosphere increases, and this increase may effect airglow emissions.

  19. Wide Angle Compton Scattering within the SCET factorization Framework

    Directory of Open Access Journals (Sweden)

    Kivel Nikolay

    2016-01-01

    Full Text Available Existing data for the electromagnetic proton form factors and for the cross section of the wide angle Compton scattering (WACS show that the hard two-gluon exchange mechanism (collinear factorization is still not applicable in the kinematical region where Mandelstam variables s ~ −t ~ −u are about few GeV2. On the other hand these observables can be described in phenomenological models where spectator quarks are soft which assumes a large contribution due to the soft-overlap mechanism. It turns out that the simple QCD factorization picture is not complete and must also include the soft-overlap contribution which can be described as a certain matrix element in the soft collinear effective theory (SCET. Then the leading power contribution to WACS amplitude is described as a sum of the hard- and soft-spectator contributions. The existing experimental data allows one to check certain conclusions based on the assumption about dominant role of the soft-spectator mechanism.

  20. Wide-Angle-Scanning Reflectarray Antennas Actuated by MEMS

    Science.gov (United States)

    Fang, Houfei; Huang, John; Thomson, Mark W.

    2009-01-01

    An effort to develop large-aperture, wide-angle-scanning reflectarray antennas for microwave radar and communication systems is underway. In an antenna of this type as envisioned, scanning of the radiated or incident microwave beam would be effected through mechanical rotation of the passive (reflective) patch antenna elements, using microelectromechanical systems (MEMS) stepping rotary actuators typified by piezoelectric micromotors. It is anticipated that the cost, mass, and complexity of such an antenna would be less than, and the reliability greater than, those of an electronically scanned phased-array antenna of comparable beam-scanning capability and angular resolution. In the design and operation of a reflectarray, one seeks to position and orient an array of passive patch elements in a geometric pattern such that, through constructive interference of the reflections from them, they collectively act as an efficient single reflector of radio waves within a desired frequency band. Typically, the patches lie in a common plane and radiation is incident upon them from a feed horn.

  1. Graded index and randomly oriented core-shell silicon nanowires for broadband and wide angle antireflection

    Directory of Open Access Journals (Sweden)

    P. Pignalosa

    2011-09-01

    Full Text Available Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In this work, we have demonstrated the random core-shell silicon nanowires with both broadband (from 400nm to 900nm and wide angle (from normal incidence to 60º antireflection characteristics within AM1.5 solar spectrum. The graded index structure from the randomly oriented core-shell (Air/SiOx/Si nanowires may provide a potential avenue to realize a broadband and wide angle antireflection layer.

  2. Extending the Utility of the Parabolic Approximation in Medical Ultrasound Using Wide-Angle Diffraction Modeling.

    Science.gov (United States)

    Soneson, Joshua E

    2017-04-01

    Wide-angle parabolic models are commonly used in geophysics and underwater acoustics but have seen little application in medical ultrasound. Here, a wide-angle model for continuous-wave high-intensity ultrasound beams is derived, which approximates the diffraction process more accurately than the commonly used Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation without increasing implementation complexity or computing time. A method for preventing the high spatial frequencies often present in source boundary conditions from corrupting the solution is presented. Simulations of shallowly focused axisymmetric beams using both the wide-angle and standard parabolic models are compared to assess the accuracy with which they model diffraction effects. The wide-angle model proposed here offers improved focusing accuracy and less error throughout the computational domain than the standard parabolic model, offering a facile method for extending the utility of existing KZK codes.

  3. Design study of a wide-angle infrared thermography and visible observation diagnostic on JT-60SA

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, K., E-mail: kamiya.kensaku@jaea.go.jp [Japan Atomic Energy Agency (JAEA), Naka 311-0193, Ibaraki-ken (Japan); Itami, K.; Takeuchi, M. [Japan Atomic Energy Agency (JAEA), Naka 311-0193, Ibaraki-ken (Japan); Enokuchi, A. [Genesia Co., Mitaka, Tokyo 181-0013 (Japan)

    2014-12-15

    Design study of a wide-angle infrared (IR) thermography (surface temperature measurement) and visible observation diagnostics for JT-60SA are reported. The new design offers an optical solution without a “blind spot” which is one of the advantages. In order to image a large section inside the vacuum vessel (both in poloidal and toroidal directions), the optical system of endoscope is to provide a wide-angle view in the IR and visible wavelength ranges. The estimated IR optical spatial resolution is approximately 2 cm at a distance of 7.6 m from the front optics with a pupil diameter of 4 mm. For a surface temperature measurement it would be larger (∼4 cm for a surface temperature error less than 5%). The optics of this system can be divided into three parts: (1) a mirror based optical head (two set of spherical mirrors plus two flat mirrors) that produces an intermediate image, (2) a Cassegrain telescope system, and (3) a relay group of lenses, being adapted to the two kinds of detectors for IR and visible observations.

  4. A wide-angle metamaterial narrow-band-stop filter for 532 nm wavelength green light

    CERN Document Server

    Yue, Liyang; Yan, Bing; Tung, Nguyen Thanh; Lam, Vu Dinh; Wang, Zengbo

    2016-01-01

    Traditional optical interference narrow-band-stop filters do not possess wide-angle property, because peaks and troughs of filter spectrum would be moved at a non-normal angle of incidence (AOI), which could result in functional failure in particular cases, e.g. blocking of laser for pilot in cockpit during premeditated laser pointer direct. For this reason, we designed a wide-angle metamaterial narrow-band-stop filter assembled by cross shaped units to block 532 nm green light, which is firstly reported in the world. Unnecessary shift of spectrum caused by AOI change is effectively inhibited, and angular tolerance of wide-angle capability achieves to 35 degrees non-normal AOIs.

  5. Wide-angle imaging system with fiberoptic components providing angle-dependent virtual material stops

    Science.gov (United States)

    Vaughan, Arthur H. (Inventor)

    1993-01-01

    A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180 deg strip or arc of a target image. Light received by the spherical mirror section is reflected to a frustoconical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180 deg strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.

  6. Crustal wide-angle reflection imaging along Lianxian-Gangkou profile in Guangdong province, China

    Institute of Scientific and Technical Information of China (English)

    Zhongjie Zhang; Bing Zhao; Xi Zhang; Jiwen Teng

    2009-01-01

    A 400 km-long wide-angle seismic experiment along Lianxian-Gangkou profile in South China was carried out to study contact relationship between southeast continental margin of Yangtze block and northwest continental margin of Cathaysia block. We reconstructed crustal wide-angle reflection structure by the depth-domain pre-stack migration and the crustal velocity model constructed from the traveltime fitting. The wide-angle reflection section shows different reflection (from crystalline basement and Moho) pattern beneath the Yangtze and Cathaysia blocks, and suggests the Wuchuan-Sihui fault is the boundary between them. A cluster of well-developed reflections on Mobo and in its underlying topmost mantle probably comes from al-ternative thin layers, which may be seismic signature of strong interaction between crust and mantle in the tectonic environment of lithosphere extension.

  7. Recent advancements of wide-angle polarization analysis with 3He neutron spin filters

    Science.gov (United States)

    Chen, W. C.; Gentile, T. R.; Ye, Q.; Kirchhoff, A.; Watson, S. M.; Rodriguez-Rivera, J. A.; Qiu, Y.; Broholm, C.

    2016-09-01

    Wide-angle polarization analysis with polarized 3He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over the past several years, the apparatus has undergone many upgrades to address the fundamental requirements for wide angle polarization analysis using spin exchange optical pumping based 3He NSFs. In this paper, we report substantial improvements in the on-beam-line performance of the apparatus and progress toward routine user capability. We discuss new standard samples used for 3He NSF characterization and the flipping ratio measurement on MACS. We further discuss the management of stray magnetic fields produced by operation of superconducting magnets on the MACS instrument, which can significantly reduce the 3He polarization relaxation time. Finally, we present the results of recent development of horseshoe-shaped wide angle cells.

  8. Loads Analysis of Flanges of a Transonic and Supersonic Wind Tunnel Wide Angle Diffuser

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-bing; WANG Rui; CAI Qing-qing; GAO Xin-yu

    2012-01-01

    Compared with general circular flanges, flanges on conical shells have different configurations. In the Chinese national code GBISO, however, there are no related contents about flange design of this kind of type. So, it needs to study loads of flanges of this kind of type. This paper takes the flange connection of a wide angle diffuser in a transonic and supersonic wind tunnel as the background, according to the principles of flange design in Chinese national code GB150, combining the characteristics of flanges of a wide angle diffuser, the loads of flanges have been analyzed, and the equations of loads and their locations have been presented.

  9. ITER-like wide-angle infrared thermography and visible observation diagnostic using reflective optics

    NARCIS (Netherlands)

    Gauthier, E.; Roche, H.; Thomas, E.; Droineau, S.; Bertrand, B.; Migozzi, J.B.; Vliegenthart, W.A.; Dague, L.; Andrew, P.; Tiscornia, T.; Sands, D.

    2007-01-01

    Control of the plasma-wall interaction during transient events will be a critical issue in ITER. A new ITER-like wide-angle infrared and visible diagnostic, allowing to observe plasma wall interaction in the main chamber, has been installed on JET. The design and the manufacture of the diagnostic

  10. ITER-like wide-angle infrared thermography and visible observation diagnostic using reflective optics

    NARCIS (Netherlands)

    Gauthier, E.; Roche, H.; Thomas, E.; Droineau, S.; Bertrand, B.; Migozzi, J.B.; Vliegenthart, W.A.; Dague, L.; Andrew, P.; Tiscornia, T.; Sands, D.

    2007-01-01

    Control of the plasma-wall interaction during transient events will be a critical issue in ITER. A new ITER-like wide-angle infrared and visible diagnostic, allowing to observe plasma wall interaction in the main chamber, has been installed on JET. The design and the manufacture of the diagnostic an

  11. Wide-angle spectral imaging using a Fabry-Perot interferometer

    NARCIS (Netherlands)

    Strauch, M.; Livshits, I.L.; Bociort, F.; Urbach, H.P.

    2015-01-01

    We show that wide-angle spectral imaging can be achieved with compact and cost-effective devices using Fabry-Pérot interferometers. Designs with a full field of view of 90°, in which the Fabry-Pérot interferometer is mounted either in front of an imaging lens system or behind a telecentric lens syst

  12. Short-focus and ultra-wide-angle lens design in wavefront coding

    Science.gov (United States)

    Zhang, Jiyan; Huang, Yuanqing; Xiong, Feibing

    2016-10-01

    Wavefront coding (WFC) is a hybrid technology designed to increase depth of field of conventional optics. The goal of our research is to apply this technology to the short-focus and ultra-wide-angle lens which suffers from the aberration related with large field of view (FOV) such as coma and astigmatism. WFC can also be used to compensate for other aberration which is sensitive to the FOV. Ultra-wide-angle lens has a little depth of focus because it has small F number and short-focus. We design a hybrid lens combing WFC with the ultra-wide-angle lens. The full FOV and relative aperture of the final design are up to170° and 1/1.8 respectively. The focal length is 2 mm. We adopt the cubic phase mask (CPM) in the design. The conventional design will have a wide variation of the point spread function (PSF) across the FOV and it is very sensitive with the variation of the FOV. The new design we obtain the PSF is nearly invariant over the whole FOV. But the result of the design also shows the little difference between the horizontal and vertical length of the PSF. We analyze that the CPM is non-symmetric phase mask and the FOV is so large, which will generate variation in the final image quality. For that reason, we apply a new method to avoid that happened. We try to make the rays incident on the CPM with small angle and decrease the deformation of the PSF. The experimental result shows the new method to optimize the CPM is fit for the ultra-wide-angle lens. The research above will be a helpful instruction to design the ultra-wide-angle lens with WFC.

  13. A three-dimensional wide-angle BPM for optical waveguide structures.

    Science.gov (United States)

    Ma, Changbao; Van Keuren, Edward

    2007-01-22

    Algorithms for effective modeling of optical propagation in three- dimensional waveguide structures are critical for the design of photonic devices. We present a three-dimensional (3-D) wide-angle beam propagation method (WA-BPM) using Hoekstra's scheme. A sparse matrix algebraic equation is formed and solved using iterative methods. The applicability, accuracy and effectiveness of our method are demonstrated by applying it to simulations of wide-angle beam propagation, along with a technique for shifting the simulation window to reduce the dimension of the numerical equation and a threshold technique to further ensure its convergence. These techniques can ensure the implementation of iterative methods for waveguide structures by relaxing the convergence problem, which will further enable us to develop higher-order 3-D WA-BPMs based on Padé approximant operators.

  14. Estimating wide-angle, spatially varying reflectance using time-resolved inversion of backscattered light.

    Science.gov (United States)

    Naik, Nikhil; Barsi, Christopher; Velten, Andreas; Raskar, Ramesh

    2014-05-01

    Imaging through complex media is a well-known challenge, as scattering distorts a signal and invalidates imaging equations. For coherent imaging, the input field can be reconstructed using phase conjugation or knowledge of the complex transmission matrix. However, for incoherent light, wave interference methods are limited to small viewing angles. On the other hand, time-resolved methods do not rely on signal or object phase correlations, making them suitable for reconstructing wide-angle, larger-scale objects. Previously, a time-resolved technique was demonstrated for uniformly reflecting objects. Here, we generalize the technique to reconstruct the spatially varying reflectance of shapes hidden by angle-dependent diffuse layers. The technique is a noninvasive method of imaging three-dimensional objects without relying on coherence. For a given diffuser, ultrafast measurements are used in a convex optimization program to reconstruct a wide-angle, three-dimensional reflectance function. The method has potential use for biological imaging and material characterization.

  15. Geostationary Coastal and Air Pollution Events (GeoCAPE) Wide Angle Spectrometer (WAS)

    Science.gov (United States)

    Kotecki, Carl; Chu, Martha; Mannino, Antonio; Marx, Catherine Trout; Bowers, Gregory A.; Bolognese, Jeffrey A.; Matson, Elizabeth A.; McBirney, Thomas R.; Earle, Cleland P.; Choi, Michael K.; Stoneking, Eric; Luu, Kequan; Monosmith, William B.; Secunda, Mark S.; Brall, Aron; Samuels, Cabin

    2014-01-01

    The GeoCAPE Wide Angle Spectrometer (WAS) Study was a revisit of the COEDI Study from 2012. The customer primary goals were to keep mass, volume and cost to a minimum while meeting the science objectives and maximizing flight opportunities by fitting on the largest number of GEO accommodations possible. Riding on a commercial GEO satellite minimizes total mission costs. For this study, it is desired to increase the coverage rate,km2min, while maintaining ground sample size, 375m, and spectral resolution, 0.4-0.5nm native resolution. To be able to do this, the IFOV was significantly increased, hence the wide angle moniker. The field of view for COEDI was +0.6 degrees or (2048) 375m ground pixels. The WAS Threshold (the IDL study baseline design) is +2.4 degrees IDL study baseline design) is +2.4 degrees.

  16. Wide-angle beam splitting by use of positive-negative refraction in photonic crystals.

    Science.gov (United States)

    Luo, Ye; Zhang, Wei; Huang, Yidong; Zhao, Jianhui; Peng, Jiangde

    2004-12-15

    We present a positive-negative refraction effect in which, under certain conditions, an incident plane wave launched into a photonic crystal excites a positive-refracted Bloch wave and a negative-refracted Bloch wave simultaneously, both of which maintain the polarization. By utilizing this phenomenon, wide-angle beam splitting can be realized at the microscale level. Numerical simulations are employed to demonstrate this anomalous refraction behavior.

  17. Detection of Clinically Significant Retinopathy of Prematurity Using Wide-angle Digital Retinal Photography

    Science.gov (United States)

    Chiang, Michael F.; Melia, Michele; Buffenn, Angela N.; Lambert, Scott R.; Recchia, Franco M.; Simpson, Jennifer L.; Yang, Michael B.

    2013-01-01

    Objective To evaluate the accuracy of detecting clinically significant retinopathy of prematurity (ROP) using wide-angle digital retinal photography. Methods Literature searches of PubMed and the Cochrane Library databases were conducted last on December 7, 2010, and yielded 414 unique citations. The authors assessed these 414 citations and marked 82 that potentially met the inclusion criteria. These 82 studies were reviewed in full text; 28 studies met inclusion criteria. The authors extracted from these studies information about study design, interventions, outcomes, and study quality. After data abstraction, 18 were excluded for study deficiencies or because they were superseded by a more recent publication. The methodologist reviewed the remaining 10 studies and assigned ratings of evidence quality; 7 studies were rated level I evidence and 3 studies were rated level III evidence. Results There is level I evidence from ≥5 studies demonstrating that digital retinal photography has high accuracy for detection of clinically significant ROP. Level III studies have reported high accuracy, without any detectable complications, from real-world operational programs intended to detect clinically significant ROP through remote site interpretation of wide-angle retinal photographs. Conclusions Wide-angle digital retinal photography has the potential to complement standard ROP care. It may provide advantages through objective documentation of clinical examination findings, improved recognition of disease progression by comparing previous photographs, and the creation of image libraries for education and research. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references. PMID:22541632

  18. Study on the wide-angle Michelson interferometer with large air gap.

    Science.gov (United States)

    Gao, Haiyang; Tang, Yuanhe; Hua, Dengxin; Liu, Hanchen

    2011-10-10

    A wide-angle Michelson interferometer with large air gap is proposed to effectively reduce the size of the glass arms and constraint on material. It provides a novel and practical instrument for ground based wind measurement of the upper atmosphere. The field widening conditions for the large air gap are calculated in theory. For the five spectral lines of 557.7 nm, 630.0 nm, 732.0 nm, 834.6 nm, and 865.7 nm, the optimal results under ideal condition are obtained with air gaps of 1.0 cm, 1.5 cm, and 2.0 cm, respectively. With the fixed optical path difference (OPD) of 7.495 cm, three pairs of glass arms are optimized. The pair with length of 1.5 cm for air gap, 5.765 cm for H-ZF12, and 2.956 cm for H-ZLaF54, has better effect of field widening than the other two pairs and its OPD variation is only within 0.30 wavelengths at incident angle of 3°. For developing a more practical wide-angle Michelson interferometer, the H-K9L glass with size of 4.445 cm is employed as the arm material of solid interferometer. The experiment for field of view of 3° is designed and the data processing and analysis for 60 images show the agreement between experimental results and theoretical simulation. The OPD variations are only within 0.27 wavelengths for image edge. The feasibility and practicality of the wide-angle Michelson interferometer with large air gap is proved by means of theory and experiment.

  19. Studies of medium-range correlations by small-/wide-angle neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Otomo, Toshiya; Kamiyama, Takashi; Furusaka, Michihiro [Institute of Material Structure Science Lab., Neutron Science Lab., Tsukuba, Ibaraki (Japan); Kanno, Ryoji [Tokyo Institute of Technology, Dept. of Electronic Chemistry, Yokohama, Kanagawa (Japan); Yamamuro, Osamu [Osaka Univ., Graduate School of Science, Dept. of Chemistry and Microcalorimetry Research Center, Toyonaka, Osaka (Japan)

    2002-01-01

    A small/wide-angle neutron diffractometers (SWAN) covers very wide Q-range, 0.007A{sup -1} to 12A{sup -1}, therefore this instrument is useful to investigate medium-range correlations in many materials, including biological materials. Two examples are here to show the usefulness of the wide Q-range measurements to understand Li-absorption mechanism in hard-carbon as a battery anode material and to investigate medium-range correlation in vapor deposited CCl{sub 4} glass system. (author)

  20. Summer Mesosphere Temperature Distribution from Wide-Angle Polarization Measurements of the Twilight Sky

    CERN Document Server

    Ugolnikov, Oleg S

    2012-01-01

    The paper contains the results of wide-angle polarization camera (WAPC) measurements of the twilight sky background conducted in summer 2011 and 2012 at 55.2 degs.N, 37.5 degs.E, southwards from Moscow. The method of single scattering separation based on polarization data is suggested. The obtained components of scattering matrixes show the domination of Rayleigh scattering in the mesosphere for all observation days. It made possible to retrieve the altitude distribution of temperature in the mesosphere. The results are compared with the temperature data by TIMED/SABER and EOS Aura/MLS instruments for nearby dates and locations.

  1. Prestack reverse-time depth migration of arbitrarily wide-angle wave equations

    Institute of Scientific and Technical Information of China (English)

    HE Bing-shou; ZHANG Hui-xing; ZHANG Jing

    2008-01-01

    Based on arbitrarily wide-angle wave equations, a reverse-time propagation scheme is developed by substituting the partial derivatives of depth and time with central differences. The partial derivative of horizontal direction is replaced with high order difference. The imaging condition is computed by solving the eikonal equations. On the basis of above techniques, a prestack reverse-time depth migration algorithm is developed. The processing exam-ples of synthetic data show that the method can remove unwanted internal reflections and decrease the migration noise. The method also has the advantage of fidelity and is appficable of dip angle reflector imaging.

  2. Concept development for the ITER equatorial port visible∕infrared wide angle viewing system.

    Science.gov (United States)

    Reichle, R; Beaumont, B; Boilson, D; Bouhamou, R; Direz, M-F; Encheva, A; Henderson, M; Huxford, R; Kazarian, F; Lamalle, Ph; Lisgo, S; Mitteau, R; Patel, K M; Pitcher, C S; Pitts, R A; Prakash, A; Raffray, R; Schunke, B; Snipes, J; Diaz, A Suarez; Udintsev, V S; Walker, C; Walsh, M

    2012-10-01

    The ITER equatorial port visible∕infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R&D topics are outlined.

  3. Concept development for the ITER equatorial port visible/infrared wide angle viewing system

    Energy Technology Data Exchange (ETDEWEB)

    Reichle, R.; Beaumont, B.; Boilson, D.; Bouhamou, R.; Direz, M.-F.; Encheva, A.; Henderson, M.; Kazarian, F.; Lamalle, Ph.; Lisgo, S.; Mitteau, R.; Patel, K. M.; Pitcher, C. S.; Pitts, R. A.; Prakash, A.; Raffray, R.; Schunke, B.; Snipes, J.; Diaz, A. Suarez; Udintsev, V. S. [ITER Organization, Route de Vinon-sur-Verdon, 13115 St Paul-lez-Durance (France); and others

    2012-10-15

    The ITER equatorial port visible/infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R and D topics are outlined.

  4. Photonic crystals with broadband, wide-angle, and polarization-insensitive transparency.

    Science.gov (United States)

    Yao, Zhongqi; Luo, Jie; Lai, Yun

    2016-11-01

    Photonic crystals (PhCs) are well-known band gap materials that can block the propagation of electromagnetic waves within certain frequency regimes. Here, we demonstrate that PhCs can also exhibit the contrary property: broadband, wide-angle, and polarization-insensitive transparency beyond normal dielectric solids. Such high transparency attributes to robust impedance matching between a large group of eigen-states in PhCs and propagating waves in free space. As a demonstration, a transparent wall for broadband microwaves is designed for enhancing the transmittance of WiFi and 4G signals.

  5. Design and optimization of broadband wide-angle antireflection structures for binary diffractive optics.

    Science.gov (United States)

    Chang, Chih-Hao; Waller, Laura; Barbastathis, George

    2010-04-01

    We propose a class of antireflecting structures that can effectively suppress reflections for binary diffractive optics. In this structure, multiple periodic thin films with gradually varying refractive indices are used to shift all reflected diffraction to the transmitted orders. The structure is optimized to operate over broad bands and wide angles using rigorous coupled-wave analysis and genetic algorithms. We validated the structure numerically using finite-difference time-domain methods. The proposed structure may lead to more efficient diffractive devices for applications in thin-film photovoltaic, waveguide coupler, and holographic optical elements.

  6. A wide angle view imaging diagnostic with all reflective, in-vessel optics at JET

    Energy Technology Data Exchange (ETDEWEB)

    Clever, M. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, 52425 Jülich (Germany); Arnoux, G.; Balshaw, N. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Garcia-Sanchez, P. [Laboratorio Nacional de Fusion, Asociacion EURATOM-CIEMAT, Madrid (Spain); Patel, K. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Sergienko, G. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, 52425 Jülich (Germany); Soler, D. [Winlight System, 135 rue Benjamin Franklin, ZA Saint Martin, F-84120 Pertuis (France); Stamp, M.F.; Williams, J.; Zastrow, K.-D. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2013-10-15

    Highlights: ► A new wide angle view camera system has been installed at JET. ► The system helps to protect the ITER-like wall plasma facing components from damage. ► The coverage of the vessel by camera observation systems was increased. ► The system comprises an in-vessel part with parabolic and flat mirrors. ► The required image quality for plasma monitoring and wall protection was delivered. -- Abstract: A new wide angle view camera system has been installed at JET in preparation for the ITER-like wall campaigns. It considerably increases the coverage of the vessel by camera observation systems and thereby helps to protect the – compared to carbon – more fragile plasma facing components from damage. The system comprises an in-vessel part with parabolic and flat mirrors and an ex-vessel part with beam splitters, lenses and cameras. The system delivered the image quality required for plasma monitoring and wall protection.

  7. Autonomous Mobile Robot Locomotion by Multifunctional Use of Wide Angle Fovea Sensor

    Science.gov (United States)

    Shimizu, Sota

    The wide-angle fovea (WAF) sensor comprises a specially made wide-angle fovea lens and a commercially available CCD/CMOS camera with photosensitive elements of uniform size. The sensor realizes a 120-degree-wide field of view (FOV) and high magnification in the central FOV without increasing the number of pixels per image. This paper focuses on the multifunctional use of an input image with space-variant spatial resolution that enables an autonomous mobile robot to avoid obstacles during locomotion. In order to use the WAF-input image efficiently, image processing for central vision, i.e., detection of 3D obstacles, and image processing for peripheral vision, i.e., self-localization of the mobile robot, are performed simultaneously and cooperatively. The comparison of the simulation results of spatial resolutions of the WAF lens and a pinhole camera (PHC) lens shows that the WAF lens can be used for depth measurement in the central FOV and self-localization in the peripheral FOV by the parallel stereo method and the two-parallel-line algorithm, respectively. The results obtained by the WAF lens are more accurate than those obtained by the PHC lens. Autonomous locomotion of the mobile robot has been demonstrated by performing two obstacle avoidance experiments.

  8. 3-D Prestack-migration of Wide-angle Data from a Variscan Transition Zone

    Science.gov (United States)

    Bleibinhaus, F.; Bopp, M.; Simon, M.; Gebrande, H.

    1999-09-01

    In addition to the near normal-incidence observations within the German DEKORP 2 project in 1984, wide-angle observations have been carried out on a parallel profile across the boundary between the Saxothuringian and Moldanubian crust, approximately 50 km NE of the main transect to control three-dimensional variations. Explosion sources have been used for the entire survey, providing excellent conditions for wide-angle registrations. A velocity model has been derived on the basis of in- and off-line refraction measurements using a kinematic raytracer which was extended to three dimensions by interpolation of 2-D velocity fields between parallel sections. Although prestack-migration of the data led to aliasing effects due to large shot and geophone spacing, stable results were obtained by forming envelopes after single-shot migration. The migrated sections reveal a strongly reflective Moho at about 31 km depth and a steeply (50°) dipping intracrustal reflector, which seems to be related to the border between the two Variscan units.

  9. Graded index and randomly oriented core-shell silicon nanowires with broadband and wide angle antireflection for photovoltaic cell applications

    CERN Document Server

    Pignalosa, P; Qiao, L; Tseng, M; Yi, Yasha

    2011-01-01

    Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In this work, we have demonstrated the random core-shell silicon nanowires with both broadband (from 400nm to 900nm) and wide angle (from normal incidence to 60\\degree) antireflection characteristics within AM1.5 solar spectrum. The graded index structure from the randomly oriented core-shell (Air/SiOx/Si) nanowires may provide a potential avenue to realize a broadband and wide angle antireflection layer.

  10. Spoc-experiment: Wide-angle Profiling and Seismological Network Off Central Chile (october - December 2001)

    Science.gov (United States)

    Thierer, P. O.; Flueh, E. R.; Kopp, H.; Tilmann, F.; Gaedicke, C.; Schreckenberger, B.

    The main goal of the RV SONNE cruise 161 SPOC (Subduction Processes Off Chile), Leg 1 and 4, was to investigate the effects of subducting aseismic ridges and frac- ture zones on the seismicity and structure of the Central Chilean Margin. Scientists from GEOMAR (Kiel), BGR (Hannover), FU Berlin (SFB 267), Universidad de Chile (Santiago) and Instituto Costaricense de Electricidad (Costa Rica) participated in data acquisition and analysis. The SPOC experiment consists of four consecutive legs off Valparaiso, Central Chile. During Leg 1 (October), an array of 23 ocean bottom hydrophons and seismome- ters (OBH/S) was deployed to register local earthquakes. In December (Leg 4), the network was recovered and a total of 125 OBH/S locations were occupied on five wide-angle profiles. They recorded more than 10.000 airgun shots, fired by an airgun array of 20 guns with a total volume of 50 liters. In addition, the wide-angle seis- mic lines were extended by land-based seismometers, operated by the Universidad de Chile, Santiago. Furthermore gravity, magnetics and high resolution bathymetry (SIMRADTM) and sediment echo-sound data (PARASOUNDTM) were recorded. On Legs 2 and 3, the BGR carried out a multi-channel reflection (MCS) seismic survey. Preliminary analysis of the data shows that a considerable number of local earthquakes has been recorded by the passive seismological network. Preliminary location of the hypocenters yield earthquake depths predominantly between 15 and 30 km. Many events registered by the local seismological network have been relocated~10 km west- wards of the previous land-based locations, which might indicate a bias in the existing catalogues. Wide-angle record sections of high quality were obtained, for all profiles shot. Mantle phases over offsets of more than 120 km were recorded by many stations. The pre- liminary velocity depth model derived for a profile striking E-W at 31a S across the subduction zone resolved the lateral transition on the

  11. Small and Wide Angle X-ray Scattering studies of biological macromolecules in solution.

    Science.gov (United States)

    Liu, Li; Boldon, Lauren; Urquhart, Melissa; Wang, Xiangyu

    2013-01-08

    In this paper, Small and Wide Angle X-ray Scattering (SWAXS) analysis of macromolecules is demonstrated through experimentation. SWAXS is a technique where X-rays are elastically scattered by an inhomogeneous sample in the nm-range at small angles (typically 0.1 - 5°) and wide angles (typically > 5°). This technique provides information about the shape, size, and distribution of macromolecules, characteristic distances of partially ordered materials, pore sizes, and surface-to-volume ratio. Small Angle X-ray Scattering (SAXS) is capable of delivering structural information of macromolecules between 1 and 200 nm, whereas Wide Angle X-ray Scattering (WAXS) can resolve even smaller Bragg spacing of samples between 0.33 nm and 0.49 nm based on the specific system setup and detector. The spacing is determined from Bragg's law and is dependent on the wavelength and incident angle. In a SWAXS experiment, the materials can be solid or liquid and may contain solid, liquid or gaseous domains (so-called particles) of the same or another material in any combination. SWAXS applications are very broad and include colloids of all types: metals, composites, cement, oil, polymers, plastics, proteins, foods, and pharmaceuticals. For solid samples, the thickness is limited to approximately 5 mm. Usage of a lab-based SWAXS instrument is detailed in this paper. With the available software (e.g., GNOM-ATSAS 2.3 package by D. Svergun EMBL-Hamburg and EasySWAXS software) for the SWAXS system, an experiment can be conducted to determine certain parameters of interest for the given sample. One example of a biological macromolecule experiment is the analysis of 2 wt% lysozyme in a water-based aqueous buffer which can be chosen and prepared through numerous methods. The preparation of the sample follows the guidelines below in the Preparation of the Sample section. Through SWAXS experimentation, important structural parameters of lysozyme, e.g. the radius of gyration, can be analyzed.

  12. Modeling of the ITER-like wide-angle infrared thermography view of JET.

    Science.gov (United States)

    Aumeunier, M-H; Firdaouss, M; Travère, J-M; Loarer, T; Gauthier, E; Martin, V; Chabaud, D; Humbert, E

    2012-10-01

    Infrared (IR) thermography systems are mandatory to ensure safe plasma operation in fusion devices. However, IR measurements are made much more complicated in metallic environment because of the spurious contributions of the reflected fluxes. This paper presents a full predictive photonic simulation able to assess accurately the surface temperature measurement with classical IR thermography from a given plasma scenario and by taking into account the optical properties of PFCs materials. This simulation has been carried out the ITER-like wide angle infrared camera view of JET in comparing with experimental data. The consequences and the effects of the low emissivity and the bidirectional reflectivity distribution function used in the model for the metallic PFCs on the contribution of the reflected flux in the analysis are discussed.

  13. Wide angle imaging lidar (WAIL): theory of operation, cross-platform validation, and potential applications.

    Energy Technology Data Exchange (ETDEWEB)

    Polonsky, I. N. (Igor N.); Davis, A. B. (Anthony B.); Love, S. P. (Steven P.)

    2004-01-01

    The Wide-Angle Imaging Lidar (WAIL), a new instrument, that measures cloud optical and geometrical properties by means of off-beam lidar returns, was deployed as part of a multi-instrument campaign to probe a cloud field at ARM (Atmospheric Radiation Measurement) Southern Great Plain (SGP) site on March 25, 2002. WAIL is designed to determine physical and geometrical characteristics using the off-beam component of the lidar return that can be adequately modeled within the diffusion approximation. Using WAIL data, we estimate the extinction coefficient and geometrical thickness of a dense cloud layer; from there, we infer optical thickness. Results from the new methodology agree well with counterparts obtained from other instruments located permanently at the SGP ARM site and from the WAIL-like airborne instrument that flew over the site during our observation period.

  14. A Robotic Wide-Angle H-Alpha Survey of the Southern Sky

    CERN Document Server

    Gaustad, J E; Rosing, W; Van Buren, D T

    2001-01-01

    We have completed a robotic wide-angle imaging survey of the southern sky (declination less than +15 degrees) at 656.3 nm wavelength, the H-alpha emission line of hydrogen. Each image of the resulting Southern H-Alpha Sky Survey Atlas (SHASSA) covers an area of the sky 13 degrees square at an angular resolution of approximately 0.8 arcminute, and reaches a sensitivity level of 2 rayleigh (1.2 x 10^-17 erg cm^-2 s^-1 arcsec^-2) per pixel, corresponding to an emission measure of 4 cm^-6 pc, and to a brightness temperature for microwave free-free emission of 12 microkelvins at 30 GHz. Smoothing over several pixels allows features as faint as 0.5 rayleigh to be detected.

  15. Modeling of the ITER-like wide-angle infrared thermography view of JET

    Energy Technology Data Exchange (ETDEWEB)

    Aumeunier, M.-H. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); OPTIS, ZE de La Farlede, F-83078 Toulon Cedex 9 (France); Firdaouss, M.; Travere, J.-M.; Loarer, T.; Gauthier, E.; Martin, V. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Chabaud, D.; Humbert, E. [OPTIS, ZE de La Farlede, F-83078 Toulon Cedex 9 (France); Collaboration: JET-EFDA Contributors

    2012-10-15

    Infrared (IR) thermography systems are mandatory to ensure safe plasma operation in fusion devices. However, IR measurements are made much more complicated in metallic environment because of the spurious contributions of the reflected fluxes. This paper presents a full predictive photonic simulation able to assess accurately the surface temperature measurement with classical IR thermography from a given plasma scenario and by taking into account the optical properties of PFCs materials. This simulation has been carried out the ITER-like wide angle infrared camera view of JET in comparing with experimental data. The consequences and the effects of the low emissivity and the bidirectional reflectivity distribution function used in the model for the metallic PFCs on the contribution of the reflected flux in the analysis are discussed.

  16. VLA observations of the wide-angle tailed radio source 1313+073

    Energy Technology Data Exchange (ETDEWEB)

    Patnaik, A.R.; Banhatti, D.G.; Subrahmanya, C.R. (Tata Inst. of Fundamental Research, Bangalore (India). Radio Astronomy Centre)

    1984-12-15

    VLA observations at 20 and 6 cm of the wide-angle tailed source 1313+073 are presented. It has an asymmetric structure with a sharp bend in the eastern tail and a gradual bend in the western. Both tails become diffuse after the bends. Several models are explored to explain this structure and it is concluded that the tails bend because of the motion of the parent cD galaxy through the ICM, which is possible if the cluster containing the source is dynamically young. Examination of the optical fields of 26 similar sources shows that in 20 of them the parent galaxies have a fainter companion (by approx. 2 mag), or are D, cD or db. This indicates that cannibalism may be important in the formation and powering of such sources.

  17. A gas microstrip wide angle X-ray detector for application in synchrotron radiation experiments

    CERN Document Server

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Lipp, J; Mir, J A; Simmons, J E; Spill, E J; Stephenson, R; Dobson, B R; Farrow, R C; Helsby, W I; Mutikainen, R; Suni, I

    2002-01-01

    The Gas Microstrip Detector has counting rate capabilities several orders of magnitude higher than conventional wire proportional counters while providing the same (or better) energy resolution for X-rays. In addition the geometric flexibility provided by the lithographic process combined with the self-supporting properties of the substrate offers many exciting possibilities for X-ray detectors, particularly for the demanding experiments carried out on Synchrotron Radiation Sources. Using experience obtained in designing detectors for Particle Physics we have developed a detector for Wide Angle X-ray Scattering studies. The detector has a fan geometry which makes possible a gas detector with high detection efficiency, sub-millimetre spatial resolution and good energy resolution over a wide range of X-ray energy. The detector is described together with results of experiments carried out at the Daresbury Laboratory Synchrotron Radiation Source.

  18. Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

    CERN Document Server

    Fanelli, C; Hamilton, D J; Salme, G; Wojtsekhowski, B; Ahmidouch, A; Annand, J R M; Baghdasaryan, H; Beaufait, J; Bosted, P; Brash, E J; Butuceanu, C; Carter, P; Christy, E; Chudakov, E; Danagoulian, S; Day, D; Degtyarenko, P; Ent, R; Fenker, H; Fowler, M; Frlez, E; Gaskell, D; Gilman, R; Horn, T; Huber, G M; de Jager, C W; Jensen, E; Jones, M K; Kelleher, A; Keppel, C; Khandaker, M; Kohl, M; Kumbartzki, G; Lassiter, S; Li, Y; Lindgren, R; Lovelace, H; Luo, W; Mack, D; Mamyan, V; Margaziotis, D J; Markowitz, P; Maxwell, J; Mbianda, G; Meekins, D; Meziane, M; Miller, J; Mkrtchyan, A; Mkrtchyan, H; Mulholland, J; Nelyubin, V; Pentchev, L; Perdrisat, C F; Piasetzky, E; Prok, Y; Puckett, A J R; Punjabi, V; Shabestari, M; Shahinyan, A; Slifer, K; Smith, G; Solvignon, P; Subedi, R; Wesselmann, F R; Wood, S; Ye, Z; Zheng, X

    2015-01-01

    Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The WACS polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of \\cma$= 70^\\circ$. The longitudinal transfer \\KLL, measured to be $0.645 \\pm 0.059 \\pm 0.048$, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is $\\sim$3 times larger than predicted by the GPD-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

  19. Visible-infrared achromatic imaging by wavefront coding with wide-angle automobile camera

    Science.gov (United States)

    Ohta, Mitsuhiko; Sakita, Koichi; Shimano, Takeshi; Sugiyama, Takashi; Shibasaki, Susumu

    2016-09-01

    We perform an experiment of achromatic imaging with wavefront coding (WFC) using a wide-angle automobile lens. Our original annular phase mask for WFC was inserted to the lens, for which the difference between the focal positions at 400 nm and at 950 nm is 0.10 mm. We acquired images of objects using a WFC camera with this lens under the conditions of visible and infrared light. As a result, the effect of the removal of the chromatic aberration of the WFC system was successfully determined. Moreover, we fabricated a demonstration set assuming the use of a night vision camera in an automobile and showed the effect of the WFC system.

  20. The complex Jacobi iterative method for three-dimensional wide-angle beam propagation.

    Science.gov (United States)

    Le, Khai Q; Godoy-Rubio, R; Bienstman, Peter; Hadley, G Ronald

    2008-10-13

    A new complex Jacobi iterative technique adapted for the solution of three-dimensional (3D) wide-angle (WA) beam propagation is presented. The beam propagation equation for analysis of optical propagation in waveguide structures is based on a novel modified Padé(1,1) approximant operator, which gives evanescent waves the desired damping. The resulting approach allows more accurate approximations to the true Helmholtz equation than the standard Padé approximant operators. Furthermore, a performance comparison of the traditional direct matrix inversion and this new iterative technique for WA-beam propagation method is reported. It is shown that complex Jacobi iteration is faster and better-suited for large problems or structures than direct matrix inversion.

  1. A wide-angle broadband absorber in graphene-based hyperbolic metamaterials

    Science.gov (United States)

    Ning, Renxia; Liu, Shaobin; Zhang, Haifeng; Bian, Borui; Kong, Xiangkun

    2014-11-01

    A wide-angle broadband absorber which is realized by periodic structures containing graphene-based hyperbolic metamaterials (GHMM) and isotropic medium is theoretically investigated. The GHMM is composed of monolayer graphene and conventional dielectric, which the refractive index can be tuned by the chemical potential, the thickness of dielectric and phenomenological scattering rates, respectively. A periodic structure of GHMM can obtain a broadband absorption which is shown to absorb roughly 70% (relative bandwidth is larger than 45%) of all available electromagnetic wave in absorption bandwidth at normal incident angle. Compared with some previous designs, our proposed structure has a relative bandwidth over a broad frequency range in mid-infrared. This kind periodic structures offer additional opportunities to design novel optoelectronic devices.

  2. Efficient Terahertz Wide-Angle NUFFT-Based Inverse Synthetic Aperture Imaging Considering Spherical Wavefront.

    Science.gov (United States)

    Gao, Jingkun; Deng, Bin; Qin, Yuliang; Wang, Hongqiang; Li, Xiang

    2016-12-14

    An efficient wide-angle inverse synthetic aperture imaging method considering the spherical wavefront effects and suitable for the terahertz band is presented. Firstly, the echo signal model under spherical wave assumption is established, and the detailed wavefront curvature compensation method accelerated by 1D fast Fourier transform (FFT) is discussed. Then, to speed up the reconstruction procedure, the fast Gaussian gridding (FGG)-based nonuniform FFT (NUFFT) is employed to focus the image. Finally, proof-of-principle experiments are carried out and the results are compared with the ones obtained by the convolution back-projection (CBP) algorithm. The results demonstrate the effectiveness and the efficiency of the presented method. This imaging method can be directly used in the field of nondestructive detection and can also be used to provide a solution for the calculation of the far-field RCSs (Radar Cross Section) of targets in the terahertz regime.

  3. Broadband and wide-angle negative reflection at a phononic crystal boundary

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Degang; Zhu, Xuefeng, E-mail: ernestzhu.nju@gmail.com; Yi, Lin [Department of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Ye, Yangtao; Xu, Shengjun [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

    2014-01-27

    We have theoretically and experimentally demonstrated the anomalous negative reflection at the boundary of a well-designed two-dimensional phononic crystal. This exotic phenomenon is attributed to the selective enhancement of −1st order diffraction mode with the zero-order diffraction mode being dramatically suppressed. After material and structural optimization, the negative reflection can be maintained in a broadband of frequencies and for a wide incident angle range. Our system can be employed to design Littrow configuration to realize perfect broadband and wide-angle blazing. The study gives a possibility to achieve greater flexibility and stronger effects in manipulating reflected acoustic waves, which has potential applications in underwater communication, medical ultrasonics, etc.

  4. Development of one-coordinate gaseous detector for wide angle diffraction studies

    CERN Document Server

    Aulchenko, V M; Sharafutdinov, M R; Shekhtman, L I; Titov, V M; Tolochko, B P; Zhulanov, V V

    2008-01-01

    A one-coordinate gaseous detector of soft X-ray photons for wide-angle X-ray scattering (WAXS) studies is being developed. The detector operates in counting mode and is based on multi-stage Gas Electron Multiplier(GEM). Full size detector is assembled and has 67 degrees aperture with 350mm distance to the source, readout multi-strip structure with 2048 strips at 0.2mm pitch and is partially equipped with readout electronics in the central part. Main parameters of the detector have been measured with 8keV X-ray beam at VEPP-3 synchrotron ring. Spatial resolution of 470 um (FWHM) has been demonstrated that will allow to distinguish diffraction spots at 0.1 degrees.

  5. GMRT Detection of a New Wide-Angle Tail (WAT) Radio Source Associated with the Galaxy PGC 1519010

    Indian Academy of Sciences (India)

    N. G. Kantharia; M. Das; Gopal-Krishna

    2009-03-01

    We report the serendipitous detection of a Wide-Angle Tail (WAT) radio galaxy at 240 and 610 MHz, using the Giant Metrewave Radio Telescope (GMRT). This WAT is hosted by a cD galaxy PGC 1519010 whose photometric redshift given in the SDSS DR6 catalogue is close to the spectroscopic redshifts (0.105, 0.106 and 0.107) of three galaxies found within $4'$ of the cD. Using the SDSS DR6, we have identified a total of 37 galaxies within $15'$ of the cD, whose photometric redshifts are between 0.08 and 0.14. This strongly suggests that the cD is associated with a group of galaxies whose conspicuous feature is a north–south chain of galaxies (filament) extending to at least 2.6 Mpc. The ROSAT all-sky survey shows a faint, diffuse X-ray source in this direction, which probably marks the hot intracluster gas in the potential well of this group. We combine the radio structural information for this WAT with the galaxy clustering in that region to check its overall consistency with the models of WAT formation. The bending of the jet before and after its disruption forming the radio plume, are found to be correlated in this WAT, as seen from the contrasting morphological patterns on the two sides of the core. Probable constraints imposed by this on the models ofWAT formation are pointed out. We also briefly report on the other interesting radio sources found in the proximity of the WAT. These include a highly asymmetric double radio source and an ultra-steep spectrum radio source for which no optical counterpart is detected in the SDSS.

  6. Probing BL Lac and Cluster Evolution via a Wide-angle, Deep X-ray Selected Sample

    Science.gov (United States)

    Perlman, E.; Jones, L.; White, N.; Angelini, L.; Giommi, P.; McHardy, I.; Wegner, G.

    1994-12-01

    The WARPS survey (Wide-Angle ROSAT Pointed Survey) has been constructed from the archive of all public ROSAT PSPC observations, and is a subset of the WGACAT catalog. WARPS will include a complete sample of >= 100 BL Lacs at F_x >= 10(-13) erg s(-1) cm(-2) . A second selection technique will identify ~ 100 clusters at 0.15 = 0.304 +/- 0.062 for XBLs but = 0.60 +/- 0.05 for RBLs. Models of the X-ray luminosity function (XLF) are also poorly constrained. WARPS will allow us to compute an accurate XLF, decreasing the error bars above by over a factor of two. We will also test for low-luminosity BL Lacs, whose non-thermal nuclear sources are dim compared to the host galaxy. Browne and Marcha (1993) claim the EMSS missed most of these objects and is incomplete. If their predictions are correct, 20-40% of the BL Lacs we find will fall in this category, enabling us to probe the evolution and internal workings of BL Lacs at lower luminosities than ever before. By removing likely QSOs before optical spectroscopy, WARPS requires only modest amounts of telescope time. It will extend measurement of the cluster XLF both to higher redshifts (z>0.5) and lower luminosities (LX<1x10(44) erg s(-1) ) than previous measurements, confirming or rejecting the 3sigma detection of negative evolution found in the EMSS, and constraining Cold Dark Matter cosmologies. Faint NELGs are a recently discovered major contributor to the X-ray background. They are a mixture of Sy2s, starbursts and galaxies of unknown type. Detailed classification and evolution of their XLF will be determined for the first time.

  7. Synthesizing wide-angle and arbitrary view-point images from a circular camera array

    Science.gov (United States)

    Fukushima, Norishige; Yendo, Tomohiro; Fujii, Toshiaki; Tanimoto, Masayuki

    2006-02-01

    We propose a technique of Imaged-Based Rendering(IBR) using a circular camera array. By the result of having recorded the scene as surrounding the surroundings, we can synthesize a more dynamic arbitrary viewpoint images and a wide angle images like a panorama . This method is based on Ray- Space, one of the image-based rendering, like Light Field. Ray-Space is described by the position (x, y) and a direction (θ, φ) of the ray's parameter which passes a reference plane. All over this space, when the camera has been arranged circularly, the orbit of the point equivalent to an Epipor Plane Image(EPI) at the time of straight line arrangement draws a sin curve. Although described in a very clear form, in case a rendering is performed, pixel of which position of which camera being used and the work for which it asks become complicated. Therefore, the position (u, v) of the position (s, t) pixel of a camera like Light Filed redescribes space expression. It makes the position of a camera a polar-coordinates system (r, theta), and is making it close to description of Ray-Space. Thereby, although the orbit of a point serves as a complicated periodic function of periodic 2pi, the handling of a rendering becomes easy. From such space, the same as straight line arrangement, arbitrary viewpoint picture synthesizing is performed only due to a geometric relationship between cameras. Moreover, taking advantage of the characteristic of concentrating on one circular point, we propose the technique of generating a wide-angle picture like a panorama. When synthesizing a viewpoint, since it is overlapped and is recording the ray of all the directions of the same position, this becomes possible. Having stated until now is the case where it is a time of the camera fully having been arranged and a plenoptic sampling being filled. The discrete thing which does not fill a sampling is described from here. When arranging a camera in a straight line and compounding a picture, in spite of

  8. Searching for the Onset of Seafloor Spreading West of Galicia: Wide-Angle Seismic Constraints

    Science.gov (United States)

    Davy, R. G.; Minshull, T. A.; Bayrakci, G.; Bull, J. M.; Sawyer, D. S.; Klaeschen, D.; Papenberg, C. A.; Reston, T. J.; Shillington, D. J.; Ranero, C.; Zelt, C. A.

    2014-12-01

    Rifting and the subsequent breakup of continental lithosphere has given rise to the magma-poor Galicia Bank rifted margin in the North Atlantic Ocean. Hyperextension of continental crust is observed at the deep Galicia margin (west of Spain) and has been accommodated by the rotation of continental fault blocks, which are underlain by the S-reflector, an interpreted detachment fault, which has exhumed serpentinized mantle peridotite. West of these features is the enigmatic Peridotite Ridge (PR) which has been suggested to delimit the western extent of the ocean-continent transition. An outstanding question at this margin is where unequivocal oceanic crust begins, with little existing data to constrain this boundary. We present results from a 160-km-long wide-angle seismic profile, which encompasses the S-reflector to the east, the PR, and the unidentified basement west of the PR. This profile consists of 32 OBS/H recording wide angle seismic data from coincident multichannel seismic surveying. First-arrival travel time tomography models of the crustal velocity structure were produced using two algorithms, with the best fit model having a RMS travel time misfit of 38ms, a χ2 of 0.99 and strong correlation with the structure observed in seismic reflection images. East of the PR, the 3.0-3.5 kms-1 velocity contours match top of crust and the S-reflector generally lies between the 6.0-6.5 kms-1 velocity contours, giving a crustal thickness of 1.5-3.5 km and an average velocity gradient of 0.75 s-1. Similarly, west of the PR we observe a basement layer which is 2.0-4.0 km thick and has an average velocity gradient of 0.72 s-1. High velocity gradients, an absence of velocities typical of oceanic layer 3 and no clear mantle reflections suggest the continued presence of exhumed, serpentinized mantle peridotite west of the PR, which could be analogous to the large expanses of mantle peridotite exposed at the seafloor on the flanks of the ultra-slow Southwest Indian ridge.

  9. Crustal Structure Across the Three Gorges Dam from Wide-Angle Seismic Data

    Science.gov (United States)

    Zhang, Z.; Bai, Z.; Mooney, W. D.; Wang, C.; Chen, X.; Wang, E.; Teng, J.

    2007-12-01

    The Three Gorges Dam (TGD) is one of the biggest engineering projects in the world. In order to understand the crustal structure across the TGD, a wide-angle seismic profile was acquired from Fengjie, Sichuan Province, to Guanyindang, Hubei Province. The crustal velocity and reflectivity cross-section across the TGD shows lateral velocity variation and a northward-slipping, crustal-scale, strong reflector. The TGD is located at a transition in crustal thickness from about 45 km in the northwest to about 35 km in the southeast. The topography of China is characterized by three terraces. The Qinghai-Tibet Plateau is the first terrace with a surface elevation above sea level of >4500 m; the second terrace lies north and east of the Qinghai-Tibet Plateau at an elevation of 1000-2000 m; the third terrace is in the eastern part of China with an elevation of named after the three gorges of Xiling Xia, Wu Xia, and Qutang Xia (Xia means "gorge" in Chinese), is located at the middle segmentations of the Yangtze River, extending from Fengjie, Sichuan Province, to Yichang, Hubei Province, with a total length of about 200 km. Due to the abrupt relief from the second to third topographic terrace of China, the unstopping, huge amounts of river stream provide the best place for the construction of the largest hydro power plant ever in the world. In order to provide a background of the crustal environment for the dam project, a wide-angle seismic profile along the Yangtze River was carried out. Tectonically, the studied area belongs to the Yangtze block and cut several sub-tectonic units: the Wanxian depression fold belt, the Zigui platform fold belt, the southwestern Hubei province complex fold belt, the Huangling Faulted Dome (HLFD), and the Jiangling Depression (JLD). We present the interpretation results of the crustal structure along the Three Gorges extension which shows: there are strong lateral variations both of crustal thickness and P-wave velocity, the Jiangling

  10. Wide-angle ITER-prototype tangential infrared and visible viewing system for DIII-D.

    Science.gov (United States)

    Lasnier, C J; Allen, S L; Ellis, R E; Fenstermacher, M E; McLean, A G; Meyer, W H; Morris, K; Seppala, L G; Crabtree, K; Van Zeeland, M A

    2014-11-01

    An imaging system with a wide-angle tangential view of the full poloidal cross-section of the tokamak in simultaneous infrared and visible light has been installed on DIII-D. The optical train includes three polished stainless steel mirrors in vacuum, which view the tokamak through an aperture in the first mirror, similar to the design concept proposed for ITER. A dichroic beam splitter outside the vacuum separates visible and infrared (IR) light. Spatial calibration is accomplished by warping a CAD-rendered image to align with landmarks in a data image. The IR camera provides scrape-off layer heat flux profile deposition features in diverted and inner-wall-limited plasmas, such as heat flux reduction in pumped radiative divertor shots. Demonstration of the system to date includes observation of fast-ion losses to the outer wall during neutral beam injection, and shows reduced peak wall heat loading with disruption mitigation by injection of a massive gas puff.

  11. A wide angle tail radio galaxy in the COSMOS field: evidence for cluster formation

    CERN Document Server

    Smolcic, V; Finoguenov, A; Sakelliou, I; Carilli, C L; Botzler, C S; Brusa, M; Scoville, N Z; Ajiki, M; Capak, P; Guzzo, L; Hasinger, G; Impey, C; Jahnke, K; Kartaltepe, J S; McCracken, H J; Mobasher, B; Murayama, T; Sasaki, S S; Shioya, Y; Taniguchi, Y; Trump, J R

    2006-01-01

    We have identified a complex galaxy cluster system in the COSMOS field via a wide angle tail (WAT) radio galaxy consistent with the idea that WAT galaxies can be used as tracers of clusters. The WAT galaxy, CWAT-01, is coincident with an elliptical galaxy resolved in the HST-ACS image. Using the COSMOS multiwavelength data set, we derive the radio properties of CWAT-01 and use the optical and X-ray data to investigate its host environment. The cluster hosting CWAT-01 is part of a larger assembly consisting of a minimum of four X-ray luminous clusters within ~2 Mpc distance. We apply hydrodynamical models that combine ram pressure and buoyancy forces on CWAT-01. These models explain the shape of the radio jets only if the galaxy's velocity relative to the intra-cluster medium (ICM) is in the range of about 300-550 km/s which is higher than expected for brightest cluster galaxies (BCGs) in relaxed systems. This indicates that the CWAT-01 host cluster is not relaxed, but is possibly dynamically young. We argue t...

  12. Ultrathin triple-band polarization-insensitive wide-angle compact metamaterial absorber

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Shuai; Yang, Shizhong; Tao, Lu; Yang, Lisheng; Cao, Hailin, E-mail: hailincao@cqu.edu.cn [Key Laboratory of Aerocraft Tracking, Telemetering & Command and Communication Ministry of Education, Chongqing University, Chongqing, 400044 (China)

    2016-07-15

    In this study, the design, realization, and characterization of an ultrathin triple-band polarization-insensitive wide-angle metamaterial absorber are reported. The metamaterial absorber comprises a periodic array of modified six-fold symmetric snowflake-shaped resonators with strip spiral line load, which is printed on a dielectric substrate backed by a metal ground plane. It is shown that the absorber exhibits three distinct near-unity absorption peaks, which are distributed across C, X, Ku bands, respectively. Owing to the six-fold symmetry, the absorber is insensitive to the polarization of the incident radiation. In addition, the absorber shows excellent absorption performance over wide oblique incident angles for both transverse electric and transverse magnetic polarizations. Simulated surface current and field distributions at the three absorption peaks are demonstrated to understand the absorption mechanism. Particularly, the absorption modes come from the fundamental and high-order dipole resonances. Furthermore, the experimental verification of the designed absorber is conducted, and the measured results are in reasonable agreement with the simulated ones. The proposed ultrathin (∼0.018λ{sub 0}, λ{sub 0} corresponding to the lowest peak absorption frequency) compact (0.168λ{sub 0}×0.168λ{sub 0} corresponding to the area of a unit cell) absorber enables potential applications such as stealth technology, electromagnetic interference and spectrum identification.

  13. Solutions on a high-speed wide-angle zoom lens with aspheric surfaces

    Science.gov (United States)

    Yamanashi, Takanori

    2012-10-01

    Recent development in CMOS and digital camera technology has accelerated the business and market share of digital cinematography. In terms of optical design, this technology has increased the need to carefully consider pixel pitch and characteristics of the imager. When the field angle at the wide end, zoom ratio, and F-number are specified, choosing an appropriate zoom lens type is crucial. In addition, appropriate power distributions and lens configurations are required. At points near the wide end of a zoom lens, it is known that an aspheric surface is an effective means to correct off-axis aberrations. On the other hand, optical designers have to focus on manufacturability of aspheric surfaces and perform required analysis with respect to the surface shape. Centration errors aside, it is also important to know the sensitivity to aspheric shape errors and their effect on image quality. In this paper, wide angle cine zoom lens design examples are introduced and their main characteristics are described. Moreover, technical challenges are pointed out and solutions are proposed.

  14. Simulated Performance of the Orbiting Wide-angle Light Collectors (OWL) Experiment

    Science.gov (United States)

    Krizmanic, J. F.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The Orbiting Wide-angle Light collectors (OWL) experiment is in NASA's mid-term strategic plan and will stereoscopically image, from equatorial orbit, the air fluorescence signal generated by airshowers induced by the ultrahigh energy (E greater than few x 10(exp 19) eV) component of the cosmic radiation. The use of a space-based platform enables an extremely large event acceptance aperture and thus will allow a high statistics measurement of these rare events. Detailed Monte Carlo simulations are required to quantify the physics potential of the mission as well as optimize the instrumental parameters. This paper reports on the results of the GSFC Monte Carlo simulation for two different, OWL instrument baseline designs. These results indicate that, assuming a continuation of the cosmic ray spectrum (theta approximately E(exp -2.75), OWL could have an event rate of 4000 events/year with E greater than or equal to 10(exp 20) eV. Preliminary results, based upon these Monte Carlo simulations, indicate that events can be accurately reconstructed in the detector focal plane arrays for the OWL instrument baseline designs under consideration.

  15. Crustal structure of the Kapuskasing Uplift from LITHOPROBE near-vertical/wide-angle seismic reflection data

    Science.gov (United States)

    Wu, Jianjun; Mereu, Robert F.

    1992-11-01

    Reprocessing of one LITHOPROBE Kapuskasing deep seismic reflection profile discloses significant new information on the structure of the Kapuskasing Uplift (KU). The shallow structure of the Ivanhoe Lake fault zone (ILFZ), along which the high-grade granulites of the KU were thrust to the surface, is conspicuously imaged on a seismic section as a series of prominent northwest-dipping reflections with listric geometry. The new images show that the ILFZ is a steep fault (about 50 deg) near the surface which quickly flattens out at shallow depths. These reflections coincide with bright positive aeromagnetic anomalies over the fault zone. Direct correlation with geological observations indicates that the high reflectivity and high magnetism associated with the fault zone likely originate from mylonites. The reprocessing also reveals a pronounced midcrustal reflector within the Abitibi greenstone belt (AGB), dipping northwest and plunging under the KU. The existence of such a reflector is independently confirmed by wide-angle reflection data acquired from a cross-profile. This reflector is apparently also detected on two other reflection profiles crossing the ILFZ about 80 km to the southwest. Its concave-down shape and broad lateral extent suggest that it represents underthrusting of the AGB beneath the KU. With these new results, a more complete structural cross-section is constructed.

  16. Triple-band polarization-insensitive and wide-angle metamaterial array for electromagnetic energy harvesting

    Science.gov (United States)

    Zhong, Hui-Teng; Yang, Xue-Xia; Tan, Chong; Yu, Kai

    2016-12-01

    This work demonstrated a metamaterial array with polarization-insensitive and wide-angle operating in triple-band (GSM 1800, WiMAX, WLAN). The cell of the array consists of four same Split-Ring Resonators arranged in rotating central symmetry. The structure and size of the metamaterial cell were analyzed and optimized by using the microwave simulation software of CST. Meantime, we studied the absorption efficiency and harvesting efficiency under the normal and oblique incidences, energy distribution on the cell and the surface current paths. The simulation results show that the harvesting efficiency is 30%, 90%, and 74% at 1.75 GHz, 3.8 GHz, and 5.4 GHz, respectively, on the conditions of random polarization and the normal incidence. When the oblique incidence changes from 0° to 45°, this meta-harvester can also maintain effective harvesting efficiencies in triple-band. A 7 × 7 array has been fabricated and measured, and a good agreement with the simulated results was obtained.

  17. Multichannel and Wide-Angle SAR Imaging Based on Compressed Sensing

    Science.gov (United States)

    Sun, Chao; Wang, Baoping; Fang, Yang; Song, Zuxun; Wang, Shuzhen

    2017-01-01

    The multichannel or wide-angle imaging performance of synthetic aperture radar (SAR) can be improved by applying the compressed sensing (CS) theory to each channel or sub-aperture image formation independently. However, this not only neglects the complementary information between signals of each channel or sub-aperture, but also may lead to failure in guaranteeing the consistency of the position of a scatterer in different channel or sub-aperture images which will make the extraction of some scattering information become difficult. By exploiting the joint sparsity of the signal ensemble, this paper proposes a novel CS-based method for joint sparse recovery of all channel or sub-aperture images. Solving the joint sparse recovery problem with a modified orthogonal matching pursuit algorithm, the recovery precision of scatterers is effectively improved and the scattering information is also preserved during the image formation process. Finally, the simulation and real data is used for verifying the effectiveness of the proposed method. Compared with single channel or sub-aperture independent CS processing, the proposed method can not only obtain better imaging performance with fewer measurements, but also preserve more valuable scattering information for target recognition. PMID:28165433

  18. Flat-Base Broadband Multibeam Luneburg Lens for Wide Angle Scan

    CERN Document Server

    Jain, Sidharath

    2013-01-01

    In this paper we present the design of a flat-base Luneburg type of lens antenna, designed for wide angle scan. The antenna consists of a 11-layer lens, fed at its base by a 6x6 array of waveguides. The lens is broadband and has a high aperture efficiency, only 1 dB below that of a reference aperture antenna with uniform amplitude and phase distributions. Its sidelobe level is -21 dB at boresight and -13 dB when the scan angle is 64 degrees. It shows good performance when compared to the flat Luneburg lens previously reported in the literature, in terms of gain, scan capability, as well as ease of fabrication. It is shown to have the capability of producing multiple beams simultaneously, multiple angle, scan capability. Two different methodologies have been used to design the 6x6 feed array of waveguides for the lens. The first of these utilizes a conventional perfect electric conductor (PEC) waveguide, while the second employs materials for the guided wave region that have a high permittivity at frequencies ...

  19. Wide-angle lenses and image collapsing subreflectors for nontracking solar collectors.

    Science.gov (United States)

    Sletten, C J; Holt, F S; Herskovitz, S B

    1980-05-01

    This paper presents new optical methods for the design of nontracking solar energy concentrators with acceptance angles of 60 degrees in the elevation (altitude) plane and +/-50 degrees in azimuth sectors. We have designed and constructed a two-point corrected cylindrical stepped prism lens (SPL) with 30.48-cm aperture height and F/D congruent with 1, which focuses well over the acceptance interval. Image collapsing subreflector (ICS) surfaces are synthesized that reflect the incident illumination refracted by the lens onto a small fixed absorbing area or shelf ~7.6 cm wide resulting in near maximum theoretical concentration ratios for these broad acceptance angles. Nearly 100% of the incident optical rays intercept the absorber shelf. The wide-angle and image collapsing optical properties were confirmed by laser and solar experiments. Rooftop thermal tests on a 30.5 x 30.5-cm collector section using selectively absorbing tubes with water as circulant were conducted that indicate aperture efficiencies of ~60% could be exected on large area collectors based on this design.

  20. Evaluation of the Quality of Action Cameras with Wide-Angle Lenses in Uav Photogrammetry

    Science.gov (United States)

    Hastedt, H.; Ekkel, T.; Luhmann, T.

    2016-06-01

    The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens) offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

  1. EVALUATION OF THE QUALITY OF ACTION CAMERAS WITH WIDE-ANGLE LENSES IN UAV PHOTOGRAMMETRY

    Directory of Open Access Journals (Sweden)

    H. Hastedt

    2016-06-01

    Full Text Available The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

  2. Feedback by AGN Jets and Wide-Angle Winds on a Galactic Scale

    CERN Document Server

    Dugan, Zachary; Silk, Joseph

    2016-01-01

    To investigate the differences in mechanical feedback from radio-loud and radio-quiet Active Galactic Nuclei (AGN) on the host galaxy, we perform 3D AMR hydrodynamic simulations of wide angle, radio-quiet winds with different inclinations on a single, massive, gas-rich disk galaxy at a redshift of 2-3. We compare our results to hydrodynamic simulations of the same galaxy but with a jet. The jet has an inclination of 0 degrees (perpendicular to the galactic plane), and the winds have inclinations of 0, 45, and 90 degrees. We analyze the impact on the host's gas, star formation, and circum-galactic medium. We find that jet feedback is energy-driven and wind feedback is momentum-driven. In all the simulations, the jet or wind creates a cavity mostly devoid of dense gas in the nuclear region where star formation is then quenched, but we find strong positive feedback in all the simulations at radii greater than 3 kpc. All four simulations have similar SFRs and stellar velocities with large radial and vertical comp...

  3. A double area detector system for simultaneous small and wide-angle X-ray scattering

    CERN Document Server

    Pokric, B; Ryan, A J; Fairclough, P; Dobson, B R; Derbyshire, G E; Helsby, W; Long, G; Moon, K

    2002-01-01

    A novel area detector has been designed for material science SR studies, capable of simultaneously collecting the diffraction data in two angular regimes. The detector for collecting wide-angle X-ray scattering (WAXS) data consists of four taper-coupled CCDs arranged as a 2x2 mosaic with a central aperture about 40 mm in diameter, so permitting the inclusion of a distant on-axis CCD detector for small-angle X-ray scattering (SAXS). The distance of the SAXS detector from the sample can be varied over the range 0.27 m to about 2 m. The overall aperture of WAXS detector is approximately 200x200 mm sup 2 allowing the measurement of the diffraction patterns from 5 deg. to 45 deg. with an average angular resolution of 0.05 deg. The parallax error for large angles is substantially reduced as the individual WAXS CCDs are tilted towards the specimen location. Both WAXS and SAXS diffraction data are simultaneously collected at 30 MB/s data rate, which is equivalent to 6 complete frames per second. Each pixel value is d...

  4. Tunable graphene-based mid-infrared plasmonic wide-angle narrowband perfect absorber

    Science.gov (United States)

    Li, Hongju; Wang, Lingling; Zhai, Xiang

    2016-11-01

    In this paper, the periodic double-layer graphene ribbon arrays placed near a metallic ground plate coated by a dielectric layer are proposed and analyzed by the coupled-mode theory (CMT) to predict the perfect absorption response in the mid-infrared region. Numerical simulations of the finite-difference time-domain (FDTD) method confirm this effect and give the underlying physical origin. The anti-symmetric dipole-dipole coupling mode is supported by the double-layer graphene ribbons and acts as the electrical resonance to suppress the reflection, because of the impedance matching. The transmission from this system is restricted by the ultra-thick metallic ground plate. All incident electromagnetic energy is efficiently confined in the interlayer between graphene ribbons and the metallic plate, and the dramatic narrowband perfect absorption peak with the FWHM (full width at half maximums) of 300 nm hence is achieved. The spectral position of the absorption peak can be dynamically tuned by a small change in the chemical potential of graphene, in addition to varying geometrical parameters of the absorber. Meanwhile, this device exhibits good absorption stability over a wide angle range of incidence around ± 60° at least. Such absorber will benefit the fabrication of mid-infrared nano-photonic devices for optical filtering and storage.

  5. Anomalously-dense firn in an ice-shelf channel revealed by wide-angle radar

    Directory of Open Access Journals (Sweden)

    R. Drews

    2015-10-01

    Full Text Available The thickness of ice shelves, a basic parameter for mass balance estimates, is typically inferred using hydrostatic equilibrium for which knowledge of the depth-averaged density is essential. The densification from snow to ice depends on a number of local factors (e.g. temperature and surface mass balance causing spatial and temporal variations in density–depth profiles. However, direct measurements of firn density are sparse, requiring substantial logistical effort. Here, we infer density from radio-wave propagation speed using ground-based wide-angle radar datasets (10 MHz collected at five sites on Roi Baudouin Ice Shelf (RBIS, Dronning Maud Land, Antarctica. Using a novel algorithm including traveltime inversion and raytracing with a prescribed shape of the depth–density relationship, we show that the depth to internal reflectors, the local ice thickness and depth-averaged densities can reliably be reconstructed. For the particular case of an ice-shelf channel, where ice thickness and surface slope change substantially over a few kilometers, the radar data suggests that firn inside the channel is about 5 % denser than outside the channel. Although this density difference is at the detection limit of the radar, it is consistent with a similar density anomaly reconstructed from optical televiewing, which reveals 10 % denser firn inside compared to outside the channel. The denser firn in the ice-shelf channel should be accounted for when using the hydrostatic ice thickness for determining basal melt rates. The radar method presented here is robust and can easily be adapted to different radar frequencies and data-acquisition geometries.

  6. Wide-angle seismic reflection constraints on the lithosphere of the Variscan Belt on SW- Iberia.

    Science.gov (United States)

    Palomeras, I.; Ayarza, P.; Afonso, J.; Carbonell, R.; Martinez-Poyatos, D.; Simancas, F.; Gonzalez-Lodeiro, F.; Perez-Estaun, A.

    2008-12-01

    Two wide-angle seismic transects (A and B) were acquired across the Variscan Belt on SW-Iberia. They run across three major tectonic units in the area: South Portuguese Zone, Ossa-Morena Zone, and Central Iberian Zone. Transect A is approximately 300 km long and coincides with the course of the IBERSEIS deep seismic reflection profile. Transect B is 220 km long and is located to the SE of Transect A. The close station spacing along the transects (400 m on Transect A and 150 m on Transect B) allows to identify well defined arrivals within the upper, middle and lower crust as well as in the upper mantle. Resulting velocity models were obtained by forward modeling. The most remarkable features on these models are high velocity areas at mid crustal depths (15-20 km) with velocities in the range of 6.8-7.1 km/s. The Moho discontinuity is located at 31-33 km depth, characterized by a velocity jump from 7.1 km/s to 8.2 km/s. Shot gathers show also a sharp mantle reflection at offsets larger than 180 km which has been modeled as a fairly continuous feature with a velocity increase from 8.2 km/s to 8.4 km/s at 65-67 km depth. The nature of this boundary in still uncertain but it likely reflects a lithological change with subtle velocity/density contrasts, only visible at relatively high incidence angles. The velocity depth function for the crust in the area does not fit any of the standard average crustal velocity models due to the anomalous mid crustal velocities.

  7. Accuracy and efficiency considerations for wide-angle wavefield extrapolators and scattering operators

    Science.gov (United States)

    Thomson, C. J.

    2005-10-01

    Several observations are made concerning the numerical implementation of wide-angle one-way wave equations, using for illustration scalar waves obeying the Helmholtz equation in two space dimensions. This simple case permits clear identification of a sequence of physically motivated approximations of use when the mathematically exact pseudo-differential operator (PSDO) one-way method is applied. As intuition suggests, these approximations largely depend on the medium gradients in the direction transverse to the main propagation direction. A key point is that narrow-angle approximations are to be avoided in the interests of accuracy. Another key consideration stems from the fact that the so-called `standard-ordering' PSDO indicates how lateral interpolation of the velocity structure can significantly reduce computational costs associated with the Fourier or plane-wave synthesis lying at the heart of the calculations. A third important point is that the PSDO theory shows what approximations are necessary in order to generate an exponential one-way propagator for the laterally varying case, representing the intuitive extension of classical integral-transform solutions for a laterally homogeneous medium. This exponential propagator permits larger forward stepsizes. Numerical comparisons with Helmholtz (i.e. full) wave-equation finite-difference solutions are presented for various canonical problems. These include propagation along an interfacial gradient, the effects of a compact inclusion and the formation of extended transmitted and backscattered wave trains by model roughness. The ideas extend to the 3-D, generally anisotropic case and to multiple scattering by invariant embedding. It is concluded that the method is very competitive, striking a new balance between simplifying approximations and computational labour. Complicated wave-scattering effects are retained without the need for expensive global solutions, providing a robust and flexible modelling tool.

  8. VizieR Online Data Catalog: XMM-Newton Wide Angle Survey (XWAS) (Esquej+, 2013)

    Science.gov (United States)

    Esquej, P.; Page, M.; Carrera, F. J.; Mateos, S.; Tedds, J.; Watson, M. G.; Corral, A.; Ebrero, J.; Krumpe, M.; Rosen, S. R.; Ceballos, M. T.; Schwope, A.; Page, C. G.; Alonso-Herrero, A.; Caccianiga, A.; Della Ceca, R.; Gonzalez-Martin, O.; Lamer, G.; Severgnini, P.

    2017-02-01

    Optical images are available for all our fields in the SuperCOSMOS Sky Survey (Hambly et al., 2001MNRAS.326.1279H). We obtained optical multi-fibre spectroscopy of the X-ray sources with the Anglo Australian Telescope (AAT) Two Degree Field (2dF). (2 data files).

  9. Beyond the plane-parallel and Newtonian approach: wide-angle redshift distortions and convergence in general relativity

    Energy Technology Data Exchange (ETDEWEB)

    Bertacca, Daniele; Maartens, Roy [Physics Department, University of the Western Cape, Cape Town 7535 (South Africa); Raccanelli, Alvise [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91109 (United States); Clarkson, Chris, E-mail: daniele.bertacca@pd.infn.it, E-mail: Roy.Maartens@port.ac.uk, E-mail: Alvise@caltech.edu, E-mail: Clarkson@maths.uct.ac.za [Centre for Astrophysics, Cosmology and Gravitation and Department of Mathematics and Applied Mathematics, University of Cape Town, Cape Town 7701 (South Africa)

    2012-10-01

    We extend previous analyses of wide-angle correlations in the galaxy power spectrum in redshift space to include all general relativistic effects. These general relativistic corrections to the standard approach become important on large scales and at high redshifts, and they lead to new terms in the wide-angle correlations. We show that in principle the new terms can produce corrections of nearly 10% on Gpc scales over the usual Newtonian approximation. General relativistic corrections will be important for future large-volume surveys such as SKA and Euclid, although the problem of cosmic variance will present a challenge in observing this.

  10. Doppler term in the galaxy two-point correlation function: wide-angle, velocity, Doppler lensing and cosmic acceleration effects

    OpenAIRE

    Raccanelli, Alvise; Bertacca, Daniele; Jeong, Donghui; Neyrinck, Mark C.; Szalay, Alexander S.

    2016-01-01

    We study the parity-odd part (that we shall call Doppler term) of the linear galaxy two-point correlation function that arises from wide-angle, velocity, Doppler lensing and cosmic acceleration effects. As it is important at low redshift and at large angular separations, the Doppler term is usually neglected in the current generation of galaxy surveys. For future wide-angle galaxy surveys such as Euclid, SPHEREx and SKA, however, we show that the Doppler term must be included. The effect of t...

  11. Earth's crust model of the South-Okhotsk Basin by wide-angle OBS data

    Science.gov (United States)

    Kashubin, Sergey N.; Petrov, Oleg V.; Rybalka, Alexander V.; Milshtein, Evgenia D.; Shokalsky, Sergey P.; Verba, Mark L.; Petrov, Evgeniy O.

    2017-07-01

    Deep seismic studies of the Sea of Okhotsk region started in late 1950s. Since that time, wide-angle reflection and refraction data on more than two dozen profiles were acquired. Only five of those profiles either crossed or entered the deep-water area of the South-Okhotsk Basin (also known as the Kuril Basin or the South-Okhotsk Deep-Water Trough). Only P-waves were used to develop velocity-interface models in all the early research. Thus, all seismic and geodynamic models of the Okhotsk region were based only on the information on compressional waves. Nevertheless, the use of Vp/Vs ratio in addition to P-wave velocity allows discriminating felsic and mafic crustal layers with similar Vp values. In 2007 the Russian seismic service company Sevmorgeo acquired multi-component data with ocean bottom seismometers (OBS) along the 1700-km-long north-south 2-DV-M Profile. Only P-wave information was used previously to develop models for the entire profile. In this study, a multi-wave processing, analysis, and interpretation of the OBS data are presented for the 550-km-long southern segment of this Profile that crosses the deep-water South-Okhotsk Basin. Within this segment 50 seismometers were deployed with nominal OBS station spacing of 10-12 km. Shot point spacing was 250 m. Not only primary P-waves and S-waves but also multiples and P-S, S-P converted waves were analyzed in this study to constrain velocity-interface models by means of travel time forward modeling. In offshore deep seismic studies, thick water layer hinders an estimation of velocities in the sedimentary cover and in the upper consolidated crust. Primarily, this is due to the fact that refracted waves propagating in low-velocity solid upper layers interfere with high-amplitude direct water wave. However, in multi-component measurements with ocean bottom seismometers, it is possible to use converted and multiple waves for velocity estimations in these layers. Consequently, one can obtain P- and S

  12. Wide-angle seismic constraints on the nature, origin and evolution of the SW Iberian margins

    Science.gov (United States)

    Sallares, V.; Gailler, A.; Gutscher, M.; Martínez-Loriente, S.; Bartolome, R.; Graindorge, D.; Diaz, J.; Gracia, E.

    2011-12-01

    We investigate the crustal structure of the SW Iberian margin along two new refraction and wide-angle reflection seismic profiles acquired during the NEAREST-2008 survey; one crossing from the central Gulf of Cadiz to the Variscan continental margin in the Algarve, Southern Portugal (P1), and the other crossing the Gorringe bank from Tagus Abyssal plain to the Seine Abyssal plain (P2). P1 shows shows a sharp transition between the ~30 km-thick Variscan domain in the north and a ~7 km-thick and ~150 km-wide crustal section that is oceanic in nature. The sharp transition between continental and oceanic crust is best explained by an initial rifting setting as a transform margin during the Early Jurassic that followed the continental break-up in the Central Atlantic. The narrow oceanic basin would have formed during an oblique rifting and seafloor spreading episode between Iberia and Africa that lasted up to the initiation of oceanic spreading in the North Atlantic (earliest Cretaceous). This oceanic plate segment could be the last remnant of an oceanic corridor that once connected the Alpine-Tethys with the Atlantic ocean. This interpretation is consistent with geodynamic models suggesting the existence of a narrow oceanic slab beneath the Gibraltar arc-Alboran basin system. In P2, the most striking observation is that the Tagus and Horseshoe Abyssal plains, as well as the Gorringe bank, show the same basement velocity structure, suggesting a common nature and origin. The velocity and density gradient confirms that the basement in these domains is made of highly serpentinized, exhumed mantle, probably emplaced during the initial phases of rifting at the of the North Atlantic in the Early Cretaceous. In contrast, the Seine Abyssal plain south from Coral Patch show evidences for the presence of a well-developed oceanic crust, similar to that described along P1. Therefore, these new observations provide key constraints to better understand the initial phases of rifting

  13. An iterative method for the computation of nonlinear, wide-angle, pulsed acoustic fields of medical diagnostic transducers

    NARCIS (Netherlands)

    Huijssen, J.; Verweij, M.D.

    2010-01-01

    The development and optimization of medical ultrasound transducers and imaging modalities require a computational method that accurately predicts the nonlinear acoustic pressure field. A prospective method should provide the wide-angle, pulsed field emitted by an arbitrary planar source distribution

  14. Environmental Challenges Related to the Acquisition of the Trans Carpathian Wide Angle Reflection and Refraction Line

    Science.gov (United States)

    Dragut, Dorina-Alina; Schultz, Gehrig; Mocanu, Victor; Stephenson, Randell; Janik, Tomasz; Starostenko, Vitaly

    2015-04-01

    Complex structures like the Carpathian Orogen and its neighbouring platforms and related inter-orogenic basin system can be understood only by complex integration of complementary investigative tools. Most of regional geoscientific investigations in Romania have targeted the very intricate, high intermediate-depth seismicity, clustered Carpathian Bend Zone: Vrancea. Despite huge geological and geophysical efforts, the area remains a matter of robust debate, at least from the point of view of geodynamic driving mechanisms. However, other areas outside Vrancea remained somehow "orphaned". However, a large wide angle refraction and reflection (WARR) survey was carried out in the summer of 2014 by a large international partnership in order to study the transition from the East European Platform to the northern part of the Romanian Eastern Carpathians, Transylvanian Basin and the Apuseni Mountains. The main scientific objectives of the WARR project relate to three main investigation domains: crustal architecture; affinity of crystalline basement and sedimentary basins architecture. The profile is about 700 km in total, in Ukraine and Romania. Recorders were placed at 1.75 - 2.0 km intervals along an alignment forming the Romanian segment. Recorders used were stand-alone DSS Cubes from the Helmholz Center of GFZ Potsdam and from the Institute of Geophysics of the Polish Academy of Sciences. The seismic sources were explosives ("Riogel" and "Riodet" by Maxam), with shotpoints spaced at 20 - 65 km with a total of 800 - 1200 kg explosives/site in clusters of drill-holes loaded with 50 kg explosive/hole, average depth of 25 m. Very complicated and legally-challenging environmental permitting requirements represented a real issue for successful implementation of the project. The main concern of local and central authorities related to potential pollution of sensitive components. Here, we present the strategy, actions and results concluded in order to reach the scientific and

  15. Various Approaches to Forward and Inverse Wide-Angle Seismic Modelling Tested on Data from DOBRE-4 Experiment

    Directory of Open Access Journals (Sweden)

    Janik Tomasz

    2016-12-01

    Full Text Available The interpretation of seismic refraction and wide angle reflection data usually involves the creation of a velocity model based on an inverse or forward modelling of the travel times of crustal and mantle phases using the ray theory approach. The modelling codes differ in terms of model parameterization, data used for modelling, regularization of the result, etc. It is helpful to know the capabilities, advantages and limitations of the code used compared to others.

  16. The Orbiting Wide-Angle Light Collectors (OWL) Mission for Charged-Particle Astronomy

    Science.gov (United States)

    Mitchell, John; Krizmanic, J. F.; Stecker, F. W.; Streitmatter, R. E.

    2009-01-01

    The space-based OWL mission is designed to perform high-statistics measurements of ultra-high-energy cosmic rays (UHECR) using the Earth's atmosphere as a vast particle calorimeter, furthering the field of charged-particle astronomy. OWL has been developed in formal NASA instrument and mission studies and is comprised of two large telescopes separated by approx.600 km in 1000 km, near-equatorial orbits to stereoscopically image the near-UV air fluorescence emitted by UHECR-induced particle cascades. The High Resolution Fly's Eye (HiRes) Collaboration, and subsequently the Pierre Auger Observatory, recently reported confirmation of the expected Greisen-Zatsepin-Kuzmin (GZK) suppression of the UHECR flux above a few times 10(exp 19) eV. This observation is consistent with the majority of UHECR originating in astrophysical objects and reduces the need to invoke exotic physical processes. Particles observed above the GZK threshold energy must have come from sources within about 100 Mpc from the Earth. The small particle deflection angles expected at UHECR energies, with standard assumptions of extragalactic magnetic fields, are on the order of 1 degree. Thus by observing particles above the GZK threshold with sufficient exposure, there is the potential of identifying and characterizing individual UHECR sources. Auger has reported significant anisotropy in the arrival directions of UHECR at energies above about 6 10(exp 19) eV observed in the South, and a correlation to AGN in the 12th VCV catalog, suggesting that the sources of UHECR are traced by the distribution of luminous matter in the Universe. However, with similar statistics and the same event selection criteria, HiRes observations in the North are consistent with isotropy. Extended observations by Auger-South, by Telescope Array in the North, and possibly by the proposed Auger-North, will further these investigations. However, much greater exposures will be required to fully identify individual sources and

  17. The Orbiting Wide-Angle Light Collectors (OWL) Mission for Charged-Particle Astronomy

    Science.gov (United States)

    Mitchell, John; Krizmanic, J. F.; Stecker, F. W.; Streitmatter, R. E.

    2009-01-01

    The space-based OWL mission is designed to perform high-statistics measurements of ultra-high-energy cosmic rays (UHECR) using the Earth's atmosphere as a vast particle calorimeter, furthering the field of charged-particle astronomy. OWL has been developed in formal NASA instrument and mission studies and is comprised of two large telescopes separated by approx.600 km in 1000 km, near-equatorial orbits to stereoscopically image the near-UV air fluorescence emitted by UHECR-induced particle cascades. The High Resolution Fly's Eye (HiRes) Collaboration, and subsequently the Pierre Auger Observatory, recently reported confirmation of the expected Greisen-Zatsepin-Kuzmin (GZK) suppression of the UHECR flux above a few times 10(exp 19) eV. This observation is consistent with the majority of UHECR originating in astrophysical objects and reduces the need to invoke exotic physical processes. Particles observed above the GZK threshold energy must have come from sources within about 100 Mpc from the Earth. The small particle deflection angles expected at UHECR energies, with standard assumptions of extragalactic magnetic fields, are on the order of 1 degree. Thus by observing particles above the GZK threshold with sufficient exposure, there is the potential of identifying and characterizing individual UHECR sources. Auger has reported significant anisotropy in the arrival directions of UHECR at energies above about 6 10(exp 19) eV observed in the South, and a correlation to AGN in the 12th VCV catalog, suggesting that the sources of UHECR are traced by the distribution of luminous matter in the Universe. However, with similar statistics and the same event selection criteria, HiRes observations in the North are consistent with isotropy. Extended observations by Auger-South, by Telescope Array in the North, and possibly by the proposed Auger-North, will further these investigations. However, much greater exposures will be required to fully identify individual sources and

  18. Improvements of Travel-time Tomography Models from Joint Inversion of Multi-channel and Wide-angle Seismic Data

    Science.gov (United States)

    Begović, Slaven; Ranero, César; Sallarès, Valentí; Meléndez, Adrià; Grevemeyer, Ingo

    2016-04-01

    Commonly multichannel seismic reflection (MCS) and wide-angle seismic (WAS) data are modeled and interpreted with different approaches. Conventional travel-time tomography models using solely WAS data lack the resolution to define the model properties and, particularly, the geometry of geologic boundaries (reflectors) with the required accuracy, specially in the shallow complex upper geological layers. We plan to mitigate this issue by combining these two different data sets, specifically taking advantage of the high redundancy of multichannel seismic (MCS) data, integrated with wide-angle seismic (WAS) data into a common inversion scheme to obtain higher-resolution velocity models (Vp), decrease Vp uncertainty and improve the geometry of reflectors. To do so, we have adapted the tomo2d and tomo3d joint refraction and reflection travel time tomography codes (Korenaga et al, 2000; Meléndez et al, 2015) to deal with streamer data and MCS acquisition geometries. The scheme results in a joint travel-time tomographic inversion based on integrated travel-time information from refracted and reflected phases from WAS data and reflected identified in the MCS common depth point (CDP) or shot gathers. To illustrate the advantages of a common inversion approach we have compared the modeling results for synthetic data sets using two different travel-time inversion strategies: We have produced seismic velocity models and reflector geometries following typical refraction and reflection travel-time tomographic strategy modeling just WAS data with a typical acquisition geometry (one OBS each 10 km). Second, we performed joint inversion of two types of seismic data sets, integrating two coincident data sets consisting of MCS data collected with a 8 km-long streamer and the WAS data into a common inversion scheme. Our synthetic results of the joint inversion indicate a 5-10 times smaller ray travel-time misfit in the deeper parts of the model, compared to models obtained using just

  19. Synchrotron radiation small- and wide- angle scattering study of dispergation of Equoral, a novel drug delivery system with cyclosporine A.

    Science.gov (United States)

    Uhríková, D; Andrýsek, T; Funari, S S; Balgavý, P

    2004-08-01

    Equoral oral solution is a novel drug delivery system for cyclosporine consisting mainly of non-ionic surfactants, polyglycerol esters and polyoxyethylated fatty acids aggregates, and gives microdispersions in the aqueous enviroment. To simulate dispergation, Equoral was mixed with varying amounts of water. Changes in the structure of the prepared aggregates were studied using synchrotron x-ray small- and wide-angle scattering. A lamellar phase is the most probable structure, arising spontaneously after dispergation of Equoral in the region of 30-70 wt% H2O.

  20. Combined multiaxial deformation of polymers with in situ small angle and wide angle x-ray scattering techniques.

    Science.gov (United States)

    Gurun, B; Thio, Y S; Bucknall, D G

    2009-12-01

    A unique multiaxial deformation device has been designed and built specifically for simultaneous synchrotron small angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS) measurements. The device can operate at strain rates of 0.0005-0.3 s(-1) and induce strains up to stretch ratios of 5. Measurements can either be made at ambient or at elevated temperatures (up to approximately 150 degrees C), the latter using a heating unit. The capabilities of the device coupled with simultaneous SAXS/WAXS measurements have been demonstrated by studying the morphological evolution of a number of polymers and their nanocomposites.

  1. Origin of the wide-angle hot H2 in DG Tauri: New insight from SINFONI spectro-imaging

    CERN Document Server

    Agra-Amboage, Vanessa; Dougados, C; Kristensen, L E; Ibgui, L; Reunanen, J

    2014-01-01

    We wish to test the origins proposed for the extended hot H2 at 2000K around the atomic jet from the T Tauri star DGTau, in order to constrain the wide-angle wind structure and the possible presence of an MHD disk wind. We present flux calibrated IFS observations in H2 1-0 S(1) obtained with SINFONI/VLT. Thanks to spatial deconvolution by the PSF and to accurate correction for uneven slit illumination, we performed a thorough analysis and modeled the morphology, kinematics, and surface brightness. We also compared our results with studies in [FeII], [OI], and FUV-pumped H2. The limb-brightened H2 emission in the blue lobe is strikingly similar to FUV-pumped H2 imaged 6yr later, confirming that they trace the same hot gas and setting an upper limit of 12km/s on any expansion proper motion. The wide-angle H2 rims are at lower blueshifts than probed by narrow long-slit spectra. We confirm that they extend to larger angle and to lower speed the onion-like velocity structure observed in optical atomic lines. The l...

  2. Subduction processes off chile (SPOC) - results from The amphibious wide-angle seismic experiment across The chilean subduction zone

    Science.gov (United States)

    Lueth, S.; Spoc Resaerch Group

    2003-04-01

    One component of the onshore-offshore, active-passive seismic experiment SPOC (Krawczyk et al., Stiller et al., this vol.) was a 2-D wide-angle seismic experiment covering the Chilean subduction zone from the Nazca Plate to the Magmatic Arc in the main cordillera. Three W-E-profiles of 52 stations each and up to 240 km long were deployed between 36° and 39° S. These profiles recorded chemical shots at their ends and, in order to extend the onshore profiles, the airgun pulses from RV SONNE cruising simultaneously on offshore profiles. On the southernmost of the three profiles OBHs/OBSs were deployed offshore, thus providing continuous wide-angle seismic data from the Nazca Plate to the South-American continent. Data examples, correlations, and velocity models along the three transects will be presented. The Moho of the subducted oceanic crust can be constrained by PmP-reflections down to 45 km depth under the coastal cordillera. The P-wave velocity field of the crust of the upper plate is characterized by gradually increasing P-wave velocities from East to West. Low seismic velocities (Vp ~6.5 km/s below 10 km depth) are observed at the eastern margin of the investigated area.

  3. Radio Galaxy Zoo: discovery of a poor cluster through a giant wide-angle tail radio galaxy

    CERN Document Server

    Banfield, J K; Kapinska, A D; Rudnick, L; Hardcastle, M J; Cotter, G; Vaughan, S; Jones, T W; Heywood, I; Wing, J D; Wong, O I; Matorny, T; Terentev, I A; Lopez-Sanchez, A R; Norris, R P; Seymour, N; Shabala, S S; Willett, K W

    2016-01-01

    We have discovered a previously unreported poor cluster of galaxies (RGZ-CL J0823.2+0333) through an unusual giant wide-angle tail radio galaxy found in the Radio Galaxy Zoo project. We obtained a spectroscopic redshift of $z=0.0897$ for the E0-type host galaxy, 2MASX J08231289+0333016, leading to M$_r = -22.6$ and a $1.4\\,$GHz radio luminosity density of $L_{\\rm 1.4} = 5.5\\times10^{24}$ W Hz$^{-1}$. These radio and optical luminosities are typical for wide-angle tailed radio galaxies near the borderline between Fanaroff-Riley (FR) classes I and II. The projected largest angular size of $\\approx8\\,$arcmin corresponds to $800\\,$kpc and the full length of the source along the curved jets/trails is $1.1\\,$Mpc in projection. X-ray data from the XMM-Newton archive yield an upper limit on the X-ray luminosity of the thermal emission surrounding RGZ J082312.9+033301,at $1.2-2.6\\times10^{43}$ erg s$^{-1}$ for assumed intra-cluster medium temperatures of $1.0-5.0\\,$keV. Our analysis of the environment surrounding RGZ ...

  4. Ultra-wide to mid-wide angle 3X zoom and focus adjustable lens design for industrial video endoscope

    Science.gov (United States)

    Yang, Dongmin

    2012-11-01

    Optical zoom lens design for industrial video endoscope faces tremendous challenges in stringent compactness requirement in both diameter and rigid length dimensions, as well as harsh environmental requirements such as high working temperature. Industrial video endoscope with optical zoom capability is increasingly demanded by market yet nowadays no such product has been commercialized. Once it succeeds, it will provide huge benefits to customers in improvement of remote visual inspection work quality and productivity. A 3X continuous optical zoom lens design with short focal length is presented in this paper. It is capable to change Field of View from ultra-wide angle as 120degrees to mid-wide angle as 40degrees. Focus distance change is from infinity to as close as 5mm. The whole lens train has a maximum diameter of 3.0mm, and overall length of 8.7mm, which makes it practical to be integrated into a 6mm industrial video endoscope. Image quality in terms of contrast and resolution exceeds today's existing commercial 6mm industrial video endoscopes. The design has also considered cost and product ruggedness requests.

  5. Wide-angle stop-gap chalcogenide photonic crystals generated by direct multiple-line laser writing

    Science.gov (United States)

    Nicoletti, E.; Bulla, D.; Luther-Davies, B.; Gu, M.

    2011-12-01

    We present the fabrication and the angle-resolved optical characterizations of three-dimensional chalcogenide photonic crystals with a wide-angle stop gap. Multiple-line scanning provides an effective remedy to the elongation of the focal spot in the z direction during direct laser writing fabrication in high refractive index and highly nonlinear chalcogenide glasses. The aspect ratio of the rods is reduced from 4.46 to 1.53, thus allowing the successful fabrication of three-dimensional chalcogenide photonic crystals with a face-centered cubic symmetry and quasi-circular rods. Suppression of the angle-resolved transmission spectra is observed at a wide range of incident angles.

  6. Broadband and wide-angle light harvesting by ultra-thin silicon solar cells with partially embedded dielectric spheres.

    Science.gov (United States)

    Yang, Zhenhai; Shang, Aixue; Qin, Linling; Zhan, Yaohui; Zhang, Cheng; Gao, Pingqi; Ye, Jichun; Li, Xiaofeng

    2016-04-01

    We propose a design of crystalline silicon thin-film solar cells (c-Si TFSCs, 2 μm-thick) configured with partially embedded dielectric spheres on the light-injecting side. The intrinsic light trapping and photoconversion are simulated by the complete optoelectronic simulation. It shows that the embedding depth of the spheres provides an effective way to modulate and significantly enhance the optical absorption. Compared to the conventional planar and front sphere systems, the optimized partially embedded sphere design enables a broadband, wide-angle, and strong optical absorption and efficient carrier transportation. Optoelectronic simulation predicts that a 2 μm-thick c-Si TFSC with half-embedded spheres shows an increment of more than 10  mA/cm2 in short-circuit current density and an enhancement ratio of more than 56% in light-conversion efficiency, compared to the conventional planar counterparts.

  7. Exploring Pore Formation of Atomic Layer Deposited Overlayers by In Situ Small- and Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Karwal, Saurabh; Aoun, Bachir; Zhao, Haiyan; Ren, Yang; Canlas, Christian; Elam, Jeffrey W.; Winans, Randall E.

    2016-10-11

    In this work, we explore the pore structure of overcoated materials by in situ synchrotron small- and wide-angle X-ray scattering (SAXS)/(WAXS). Thin films of aluminum oxide (Al2O3) and titanium dioxide (TiO2) with thicknesses of 4.9 and 2.5 nm, respectively, are prepared by atomic layer deposition (ALD) on non-porous nanoparticles. In situ X-ray measurements reveal that porosity is induced in the ALD films by annealing the samples at high temperature. Moreover, this pore formation can be attributed to densification resulting from an amorphous to crystalline phase transition of the ALD films as confirmed by high resolution X-ray diffraction (XRD) and pair distribution function (PDF). Simultaneous SAXS/WAXS results not only show that the porosity is formed by this phase transition but also that the pore size increases with temperature.

  8. Radio Galaxy Zoo: discovery of a poor cluster through a giant wide-angle tail radio galaxy

    Science.gov (United States)

    Banfield, J. K.; Andernach, H.; Kapińska, A. D.; Rudnick, L.; Hardcastle, M. J.; Cotter, G.; Vaughan, S.; Jones, T. W.; Heywood, I.; Wing, J. D.; Wong, O. I.; Matorny, T.; Terentev, I. A.; López-Sánchez, Á. R.; Norris, R. P.; Seymour, N.; Shabala, S. S.; Willett, K. W.

    2016-08-01

    We have discovered a previously unreported poor cluster of galaxies (RGZ-CL J0823.2+0333) through an unusual giant wide-angle tail radio galaxy found in the Radio Galaxy Zoo project. We obtained a spectroscopic redshift of z = 0.0897 for the E0-type host galaxy, 2MASX J08231289+0333016, leading to Mr = -22.6 and a 1.4 GHz radio luminosity density of L1.4 = 5.5 × 1024 W Hz-1. These radio and optical luminosities are typical for wide-angle tailed radio galaxies near the borderline between Fanaroff-Riley classes I and II. The projected largest angular size of ≈8 arcmin corresponds to 800 kpc and the full length of the source along the curved jets/trails is 1.1 Mpc in projection. X-ray data from the XMM-Newton archive yield an upper limit on the X-ray luminosity of the thermal emission surrounding RGZ J082312.9+033301 at 1.2-2.6 × 1043 erg s-1 for assumed intracluster medium temperatures of 1.0-5.0 keV. Our analysis of the environment surrounding RGZ J082312.9+033301 indicates that RGZ J082312.9+033301 lies within a poor cluster. The observed radio morphology suggests that (a) the host galaxy is moving at a significant velocity with respect to an ambient medium like that of at least a poor cluster, and that (b) the source may have had two ignition events of the active galactic nucleus with 107 yr in between. This reinforces the idea that an association between RGZ J082312.9+033301 and the newly discovered poor cluster exists.

  9. Various Approaches to Forward and Inverse Wide-Angle Seismic Modelling Tested on Data from DOBRE-4 Experiment

    Science.gov (United States)

    Janik, Tomasz; Środa, Piotr; Czuba, Wojciech; Lysynchuk, Dmytro

    2016-12-01

    The interpretation of seismic refraction and wide angle reflection data usually involves the creation of a velocity model based on an inverse or forward modelling of the travel times of crustal and mantle phases using the ray theory approach. The modelling codes differ in terms of model parameterization, data used for modelling, regularization of the result, etc. It is helpful to know the capabilities, advantages and limitations of the code used compared to others. This work compares some popular 2D seismic modelling codes using the dataset collected along the seismic wide-angle profile DOBRE-4, where quite peculiar/uncommon reflected phases were observed in the wavefield. The 505 km long profile was realized in southern Ukraine in 2009, using 13 shot points and 230 recording stations. Double PMP phases with a different reduced time (7.5-11 s) and a different apparent velocity, intersecting each other, are observed in the seismic wavefield. This is the most striking feature of the data. They are interpreted as reflections from strongly dipping Moho segments with an opposite dip. Two steps were used for the modelling. In the previous work by Starostenko et al. (2013), the trial-and-error forward model based on refracted and reflected phases (SEIS83 code) was published. The interesting feature is the high-amplitude (8-17 km) variability of the Moho depth in the form of downward and upward bends. This model is compared with results from other seismic inversion methods: the first arrivals tomography package FAST based on first arrivals; the JIVE3D code, which can also use later refracted arrivals and reflections; and the forward and inversion code RAYINVR using both refracted and reflected phases. Modelling with all the codes tested showed substantial variability of the Moho depth along the DOBRE-4 profile. However, SEIS83 and RAYINVR packages seem to give the most coincident results.

  10. Accurate small and wide angle x-ray scattering profiles from atomic models of proteins and nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Hung T. [BioMaPS Institute for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854 (United States); Pabit, Suzette A.; Meisburger, Steve P.; Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Case, David A., E-mail: case@biomaps.rutgers.edu [BioMaPS Institute for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854 (United States); Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854 (United States)

    2014-12-14

    A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb{sup +} and Sr{sup 2+}) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein–Zernike equations, with results from the Kovalenko–Hirata closure being closest to experiment for the cases studied here.

  11. Detection of microcalcification clusters by 2D-mammography and narrow and wide angle digital breast tomosynthesis

    Science.gov (United States)

    Hadjipanteli, Andria; Elangovan, Premkumar; Looney, Padraig T.; Mackenzie, Alistair; Wells, Kevin; Dance, David R.; Young, Kenneth C.

    2016-03-01

    The aim of this study was to compare the detection of microcalcification clusters by human observers in breast images using 2D-mammography and narrow (15°/15 projections) and wide (50°/25 projections) angle digital breast tomosynthesis (DBT). Simulated microcalcification clusters with a range of microcalcification diameters (125 μm-275 μm) were inserted into 6 cm thick simulated compressed breasts. Breast images were produced with and without inserted microcalcification clusters using a set of image modelling tools, which were developed to represent clinical imaging by mammography and tomosynthesis. Commercially available software was used for image processing and image reconstruction. The images were then used in a series of 4-alternative forced choice (4AFC) human observer experiments conducted for signal detection with the microcalcification clusters as targets. The minimum detectable calcification diameter was found for each imaging modality: (i) 2D-mammography: 164+/-5 μm (ii) narrow angle DBT: 210+/-5 μm, (iii) wide angle DBT: 255+/-4 μm. A statistically significant difference was found between the minimum detectable calcification diameters that can be detected by the three imaging modalities. Furthermore, it was found that there was not a statistically significant difference between the results of the five observers that participated in this study. In conclusion, this study presents a method that quantifies the threshold diameter required for microcalcification detection, using high resolution, realistic images with observers, for the comparison of DBT geometries with 2D-mammography. 2Dmammography can visualise smaller detail diameter than both DBT imaging modalities and narrow-angle DBT can visualise a smaller detail diameter than wide-angle DBT.

  12. Scleral buckling with a noncontact wide-angle viewing system in the management of retinal detachment with undetected retinal break: a case report

    Directory of Open Access Journals (Sweden)

    Kita M

    2013-03-01

    Full Text Available Mihori Kita, Yukiko Fujii, Naoaki Kawagoe, Sachiyo HamaDepartment of Ophthalmology, National Hospital Organization Kyoto Medical Center, Kyoto, JapanAbstract: A young patient who showed rhegmatogenous retinal detachment with preoperatively undetected retinal break was successfully treated by scleral buckling using a noncontact wide-angle viewing system.Keywords: retinal detachment, retinal breaks, scleral buckling, noncontact wide-angle viewing system

  13. The ITER Equatorial Visible/Infra-Red Wide Angle Viewing System: Status of design and R&D

    Energy Technology Data Exchange (ETDEWEB)

    Salasca, Sophie, E-mail: sophie.salasca@cea.fr [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Aumeunier, Marie-Helene; Benoit, Fabrice; Cantone, Bruno; Corre, Yann; Delchambre, Elise; Ferlet, Marc; Gauthier, Eric; Guillon, Christophe; Houtte, Didier van; Keller, Delphine; Labasse, Florence; Larroque, Sebastien; Loarer, Thierry; Micolon, Frederic; Peluso, Bertrand; Proust, Maxime [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Blanchet, David; Peneliau, Yannick [CEA, DEN/DER, F-13108 Saint-Paul-lez-Durance (France); Alonso, Javier [CIEMAT, Avda. Complutense, 40, Madrid 28040 (Spain); and others

    2015-10-15

    Highlights: • The status of Equatorial Visible/Infra-Red Wide Angle Viewing System is presented. • An assessment of measurement parameters relevant for machine protection has been done. • Remaining uncertainties will be clarified during the System Level Design (SLD). • WAVS design is not considered mature enough to launch prototypes of subcomponents. • Mandatory prototypes and qualification tests are already identified. • Next stage (SLD) will enable to do trade-offs and address pending design issues. - Abstract: The Equatorial Visible/Infra-Red Wide Angle Viewing System (WAVS) is one of the ITER key diagnostics owing to its role in machine investment protection through the monitoring of Plasma Facing Components (PFCs) by Infra-Red thermography and visible imaging. Foreseen to be installed in 4 equatorial port plugs to maximize the coverage of divertor, first wall, heating antennas and upper strike zone, the WAVS will likely be composed of 15 lines of sight and 15 optical systems transferring the light along several meters from the PFCs through the port plug and interspace up to detectors located in the port cell. After a conceptual design phase led by ITER Organization, the design is being further developed through a Framework Partnership Agreement signed between the European Domestic Agency, Fusion for Energy, and a consortium gathering CEA, CIEMAT (with INTA as third party) and Bertin Technologies company. The next design step is the System Level Design (SLD) which will enable to consolidate the WAVS specifications as well as the performance realistically achievable (taking into account ITER and project constraints). The SLD has been preceded by a preparatory phase aiming at clarifying the WAVS functions and identifying critical prototyping. The outcomes of this preparatory phase are reported in this paper. First a review by the consortium of the WAVS measurement specifications is presented, for the purpose of a clearer separation of measurement

  14. Deep Structure and Evolution of the Northeastern Gulf of Aden Margin From Wide-Angle Seismic and Thermomechanical Modeling

    Science.gov (United States)

    Watremez, L.; Leroy, S.; Rouzo, S.; D'Acremont, E.; Burov, E. B.

    2009-12-01

    The Encens survey wide-angle and gravity data (Leroy et al., Feb. March 2006) allow us to determine the deep structure of the northeastern Gulf of Aden non-volcanic passive margin. The Gulf of Aden is a young oceanic basin. Its accretion began at least 17.6 Ma ago. Its current geometry shows 1st and 2nd order segmentation. Our study focus on the second order Ashawq-Salalah segment. We studied six wide-angle seismic (WAS) and gravity profiles (three along and three across the margin). Modeling of the WAS and gravity data gives insights on the first and second orders structures : (1) Continental thinning is abrupt (15-20 km thinning along 50-100 km distance). It is accommodated by four tilted blocks. (2) The OCT is narrow (15 km wide). Its geometry is determined by the velocity models: oceanic-type upper-crust (4.5 km/s) and continental-type lower-crust (> 6.5 km/s). (3) The thickness of the oceanic crust decreases from West (10 km) to East (5.5 km). This pattern is probably linked to a variation of magma supply along the paleo-slow-spreading ridge axis. (4) A 5 km thick intermediate velocity body (7.6 to 7.8 km/s) is present at the crust-mantle interface below the margin. It is interpreted as post-rift underplated, or partly intruded, mafic material. This interpretation is consistent with the presence of a volcano evidenced by heat flow measurement and multichannel seismic reflection (Encens surveys). The studied segment is mainly characterized by abrupt continental thinning and narrow OCT. Moreover, this non-volcanic passive margin is affected by post-rift volcanism evidenced by the mafic body. We then suggest that the evolution of non-volcanic passive margins may be influenced by post-rift thermal anomalies. We will compare these above results with thermomechanical models in order to constrain the margin evolution and factors leading to the Gulf of Aden formation. Modeling is processed using Para(o)voz/Flamar code. This allows us to experiment the influence of

  15. Crustal Structure of the Central Anatolia - Eastern Mediterrenean, Turkey and Cyprus from Wide-Angle Seismic Data

    Science.gov (United States)

    Denli, Alper; Gürbüz, Cemil; Mechie, James; Weber, Michael

    2016-04-01

    As a part of the CyprusArc project, a seismic wide-angle reflection/refraction profiles were carried out in March 2010. The 300 km and 45 km long north-south trending profiles extended from Cihanbeyli in Central Anatolia to Anamur in eastern Mediterranean, Turkey and in southern Cyprus, respectively. The purpose of the project is to observe the impact of the transition from subduction to continent-continent collision of the African plate with the Anatolian plate. The field experiment comprised two land shots (1125 kg explosives) in Turkey and airguns (98 cubic liters) on the Mediterranean sea, beneath Cyprus. 244 stations were installed on land for data acquisition. 77 three-component sensors and 167 vertical-component sensors were installed along ~300 km distances between Cihanbeyli and Anamur with an average spacing of 1.25 km, on Turkey. 24 three-component sensors and 21 vertical component sensors were deployed along 45 km distances on land at southern Cyprus with an average spacing of 1.25 km. To reveal a good data quality, a visual quality check, frequency analysis and filtering were applied to the seismic data. Two land shots on Turkey (also recorded on Cyprus) and airgun shots on the Mediterranean sea beneath Cyprus, geological and previous seismic investigations provide information to derive a layered velocity models beneath from the Anatolian plateau to eastern Mediterranean, Turkey and for the ophiolite complex on Cyprus. After picking observed seismic phases, finite-differences ray tracing of the wide-angle data leads a 2-D crustal P-wave velocity models. The results show moho depth increases from 38 km to 45 km depth along north-south trending profile on Turkey and crustal thinning between south Turkey and Cyprus from 40 km to 36 km. Obtained models were further refined using forward modeling to generate synthetic seismograms for individual shot gathers. Thus, by varying the velocity structure, the theoretical times and amplitudes of the various

  16. Crustal structure beneath the Northern Mississippi Embayment from travel time inversion of vintage wide-angle seismic data

    Science.gov (United States)

    Guo, L.; Magnani, M.

    2012-12-01

    The northern Mississippi Embayment (ME) in the central US is located along the southern margin of Laurentia, a region that has been shaped by a long history of tectonic and magmatic events, including episodes of continental rifting, collision and amalgamation. In the ME these events have fundamentally altered the structure and composition of the continental lithosphere, resulting in the formation and failure of the Paleozoic Reelfoot Rift, and in the emplacement of the enigmatic mafic rift pillow at lower crustal and upper mantle depths beneath the Reelfoot Rift. Because of the spatial correlation between the present, historical and prehistorical seismicity in the New Madrid seismic zone and the mafic rift pillow, it has been proposed that this magmatic feature plays a key role in localizing strain in the Central US. Emerging evidence, however, shows that Quaternary deformation in the ME is not restricted to the New Madrid seismic zone, but encompasses a region beyond the presently seismogenic area, perhaps suggesting that the mafic rift pillow extends beyond its previously detected location. To test this hypothesis and to better constrain the lateral extent, dimension, and velocity structure of the mafic rift pillow in lower crust and upper mantle beneath the ME, we perform a travel time tomographic inversion using recent modeling codes on two vintage wide-angle seismic datasets available in the region. The data were acquired by the USGS in 1980 and 1991, and are the only seismic wide-angle crustal data constraining the geometry of the rift pillow. The 1980 USGS seismic refraction investigation consisted of a total of 34 900-1800 kg shots gathered in 9 locations and recorded by 100 portable seismographs along a series of profiles targeting the structure of the Reelfoot Rift north of Memphis, Tennessee. The 1991 USGS survey acquired a N-S 400 km-long seismic profile from Memphis, Tennessee to St. Louis, Missouri, and included 3 680-2260 kg shots recorded by ~200

  17. Segmentation of the Nazca and South American plates along the Ecuador subduction zone from wide angle seismic profiles

    Science.gov (United States)

    Gailler, Audrey; Charvis, Philippe; Flueh, Ernst R.

    2007-08-01

    We describe the deep structure of the south Colombian-northern Ecuador convergent margin using travel time inversion of wide-angle seismic data recently collected offshore. The margin appears segmented into three contrasting zones. In the North Zone, affected by four great subduction earthquakes during the 20th century, normal oceanic crust subducts beneath the oceanic Cretaceous substratum of the margin underlined by seismic velocities as high as 6.0-6.5 km/s. In the Central Zone the subducting oceanic crust is over-thickened beneath the Carnegie Ridge. A steeper slope and a well-developed, high velocity, Cretaceous oceanic basement characterizes the margin wedge. This area coincides with a gap in significant subduction earthquake activity. In the South Zone, the subducting oceanic crust is normal. The fore-arc is characterized by large sedimentary basins suggesting significant subsidence. Velocities in the margin wedge are significantly lower and denote a different nature or a higher degree of fracturing. Even if the distance between the three profiles exceeds 150 km, the structural segmentation obtained along the Ecuadorian margin correlates well with the distribution of seismic activity and the neotectonic zonation.

  18. Ewald: an extended wide-angle Laue diffractometer for the second target station of the Spallation Neutron Source.

    Science.gov (United States)

    Coates, Leighton; Robertson, Lee

    2017-08-01

    Visualizing hydrogen atoms in biological materials is one of the biggest remaining challenges in biophysical analysis. While X-ray techniques have unrivaled capacity for high-throughput structure determination, neutron diffraction is uniquely sensitive to hydrogen atom positions in crystals of biological materials and can provide a more complete picture of the atomic and electronic structures of biological macromolecules. This information can be essential in providing predictive understanding and engineering control of key biological processes, for example, in catalysis, ligand binding and light harvesting, and to guide bioengineering of enzymes and drug design. One very common and large capability gap for all neutron atomic resolution single-crystal diffractometers is the weak flux of available neutron beams, which results in limited signal-to-noise ratios giving a requirement for sample volumes of at least 0.1 mm(3). The ability to operate on crystals an order of magnitude smaller (0.01 mm(3)) will open up new and more complex systems to studies with neutrons which will help in our understanding of enzyme mechanisms and enable us to improve drugs against multi resistant bacteria. With this is mind, an extended wide-angle Laue diffractometer, 'Ewald', has been designed, which can collect data using crystal volumes below 0.01 mm(3).

  19. Crustal structure across the Møre margin, mid-Norway, from wide-angle seismic and gravity data

    DEFF Research Database (Denmark)

    Kvarven, Trond; Ebbing, Jörg; Mjelde, R.

    2014-01-01

    with a 3D-density model. Modeling of the geophysical data indicates the presence of a 12–15 km thick accumulation of sedimentary rocks in the Møre Basin. The modeling of the strike profile located closer to land shows a decrease in crustal velocity from north to south. Near the coast we observe an intra...... and refraction data were acquired in 2009; two dip-profiles which were extended by land stations, and one tie-profile parallel to the strike of the Møre–Trøndelag Fault Complex. The modeling of the wide-angle seismic data was performed with a combined inversion and forward modeling approach and validated......-crustal reflector under the Trøndelag Platform, but not under the Slørebotn Sub-basin. Furthermore, two lower crustal high-velocity bodies are modeled, one located near the Møre Marginal High and one beneath the Slørebotn Sub-basin. While the outer lower crustal body is modeled with a density allowing...

  20. Understanding nucleic acid structural changes by comparing wide-angle x-ray scattering (WAXS) experiments to molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pabit, Suzette A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA; Katz, Andrea M. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA; Tolokh, Igor S. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061, USA; Drozdetski, Aleksander [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA; Baker, Nathan [Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Onufriev, Alexey V. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061, USA; Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA; Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

    2016-05-24

    Wide-angle x-ray scattering (WAXS) is emerging as a powerful tool for increasing the resolution of solution structure measurements of biomolecules. Compared to its better known complement, small angle x-ray scattering (SAXS), WAXS targets higher scattering angles and can enhance structural studies of molecules by accessing finer details of solution structures. Although the extension from SAXS to WAXS is easy to implement experimentally, the computational tools required to fully harness the power of WAXS are still under development. Currently, WAXS is employed to study structural changes and ligand binding in proteins; however the methods are not as fully developed for nucleic acids. Here, we show how WAXS can qualitatively char- acterize nucleic acid structures as well as the small but significant structural changes driven by the addition of multivalent ions. We show the potential of WAXS to test all-atom molecular dynamics (MD) simulations and to provide insight in understanding how the trivalent ion cobalt(III) hexammine (CoHex) affects the structure of RNA and DNA helices. We find that MD simulations capture the RNA structural change that occurs due to addition of CoHex.

  1. Broadband and wide-angle RCS reduction using a 2-bit coding ultrathin metasurface at terahertz frequencies

    Science.gov (United States)

    Liang, Lanju; Wei, Minggui; Yan, Xin; Wei, Dequan; Liang, Dachuan; Han, Jiaguang; Ding, Xin; Zhang, Gaoya; Yao, Jianquan

    2016-12-01

    A novel broadband and wide-angle 2-bit coding metasurface for radar cross section (RCS) reduction is proposed and characterized at terahertz (THz) frequencies. The ultrathin metasurface is composed of four digital elements based on a metallic double cross line structure. The reflection phase difference of neighboring elements is approximately 90° over a broadband THz frequency. The mechanism of RCS reduction is achieved by optimizing the coding element sequences, which redirects the electromagnetic energies to all directions in broad frequencies. An RCS reduction of less than ‑10 dB bandwidth from 0.7 THz to 1.3 THz is achieved in the experimental and numerical simulations. The simulation results also show that broadband RCS reduction can be achieved at an incident angle below 60° for TE and TM polarizations under flat and curve coding metasurfaces. These results open a new approach to flexibly control THz waves and may offer widespread applications for novel THz devices.

  2. Uni- and bidirectional wide angle CT colonography: effect on missed areas, surface visualization, viewing time and polyp conspicuity

    Energy Technology Data Exchange (ETDEWEB)

    East, James E.; Saunders, Brian P. [St. Mark' s Hospital, Wolfson Unit for Endoscopy, London (United Kingdom); Boone, Darren; Halligan, Steve; Taylor, Stuart A. [University College Hospital, Department of Specialist Radiology, London (United Kingdom); Burling, David [St. Mark' s Hospital, Department of Intestinal Imaging, London (United Kingdom)

    2008-09-15

    The effect of field of view on mucosal visualisation and reader efficiency during three-dimensional endoluminal CT colonography (CTC) was investigated. Twenty CTC datasets were reviewed at standard 90-degree and ''wide'' 140-degree viewing angles using customised viewing software (V3D colon; Viatronix), which listed number and size of missed mucosal areas (''missed regions tool'') and percentage mucosal visualisation. We compared: (1) unidirectional and bidirectional flythrough using 140- versus 90-degree viewing angles; (2) reader analysis time comparing unidirectional 140-degree flythrough versus bidirectional 90-degree flythrough; (3) paired image snapshots of 12 polyps taken at each field of view were reviewed to assess conspicuity. All patients underwent conventional colonoscopy. Bidirectional 140-degree review reduced the numbers of missed areas by between eight- and 40-fold depending on size category, including those >1,000 mm{sup 2}, compared with standard 90-degree bidirectional flythrough (P<0.001). Combined prone-supine unidirectional 140-degree flythrough and missed area review was 3.8 min faster than 90-degree bidirectional review (9.3 versus 5.5 min, P< 0.0001) for the same surface visualisation. When viewed as pairs, polyps were rated more conspicuous with a 90-degree field of view, P=0.03. Wide-angle (140-degree) CTC can reduce both numbers of missed areas and review times. However, this may be at the expense of polyp conspicuity. (orig.)

  3. Crustal Structure across Southern Islas Marías (Nayarit, Mexico) from Wide-Angle Data (TSUJAL Project)

    Science.gov (United States)

    Nunez, D.; Barba, D. C., Sr.; Nuñez-Cornu, F. J.; Danobeitia, J.; Garcia Millan, N.

    2015-12-01

    The Mexican Pacific Margin is an interesting geological and tectonic study region due to the subduction processes that involve Rivera plate, North American plates and Jalisco Block. This region has been recently studied by the TSUJAL geophysical experiment during 2014. The main goal of this project is to achieve a better knowledge about this active margin and the seismic and tsunamigenic potential structural sources. To carry out this objective a set of multibeam bathymetric, potential fields, high resolution seismic, MCS and WAS data were obtained. In the frame of this study, we present the most significant results of wide angle seismic profile RTSIM04 carried out across the southern region of Islas Marías perpendicular to the coast towards Tepic in Nayarit with 220 km of length and SW-NE orientated. This profile is made of by a network of 4 OBS and 30 land seismic stations, deployed specially for this project, which registered the air gun shots provided by RRS James Cook every 120 s. Data obtained after processing and interpretation characterize seismically the contact zone between Rivera and North American plates from 30 to 60 km of model distance. Moreover, a cortical thickening from 9 to 20 km is observed towards to the coast. In the upper mantle, P-wave velocities of 7.9-8.4 km/s up to maximum depth of 50 km have been determined.

  4. In-situ synchrotron wide-angle X-ray diffraction as a rapid method for cocrystal/salt screening.

    Science.gov (United States)

    Dong, Pin; Lin, Ling; Li, Yongcheng; Huang, Zhengwei; Lang, Tianqun; Wu, Chuanbin; Lu, Ming

    2015-12-30

    The purpose of this work was to explore in-situ synchrotron wide-angle X-ray diffraction (WAXD) as a rapid and accurate tool to screen and monitor the formation of cocrystal/salts during heating. The active pharmaceutical ingredients (caffeine, carbamazepine and lamotrigine) were respectively mixed with the coformer (saccharin), and then heated by the hot stage. Real-time process monitoring was performed using synchrotron WAXD to assess cocrystal formation and subsequently compared to differential scanning calorimetry (DSC) measurements. The effect of heating rates and cocrystal growth behavior were investigated. Synchrotron WAXD was fast and sensitive to detect cocrystal formation with the appearance of characteristic diffraction rings, even at the heating rate of 30°C/min, while DSC curves showed overlapped peaks. Unlike the indirect characterization of DSC on endo/exothermic peaks, synchrotron WAXD can directly and qualitatively determine cocrystal by diffraction peaks. The diffraction intensity-temperature curves and the corresponding first-derivative curves clearly exhibited the growth behavior of cocrystal upon heating, providing useful information to optimize the process temperature of hot melt extrusion to continuously manufacture cocrystal. The study suggests that in-situ synchrotron WAXD could provide a one-step process to screen cocrystal at high efficiency and reveal the details of cocrystal/salts growth behavior.

  5. Approach for simultaneous measurement of two-dimensional angular distribution of charged particles. III. Fine focusing of wide-angle beams in multiple lens systems

    Science.gov (United States)

    Matsuda, Hiroyuki; Daimon, Hiroshi; Tóth, László; Matsui, Fumihiko

    2007-04-01

    This paper provides a way of focusing wide-angle charged-particle beams in multiple lens systems. In previous papers [H. Matsuda , Phys. Rev. E 71, 066503 (2005); 74, 036501 (2006)], it was shown that an ellipsoidal mesh, combined with electrostatic lenses, enables correction of spherical aberration over wide acceptance angles up to ±60° . In this paper, practical situations where ordinary electron lenses are arranged behind the wide-angle electrostatic lenses are taken into account using ray tracing calculation. For practical realization of the wide-angle lens systems, the acceptance angle is set to ±50° . We note that the output beams of the wide-angle electrostatic lenses have somewhat large divergence angles which cause unacceptable or non-negligible spherical aberration in additional lenses. A solution to this problem is presented showing that lens combinations to cancel spherical aberration are available, whereby wide-angle charged-particle beams can be finely focused with considerably reduced divergence angles less than ±5° .

  6. Nature of the lithosphere across the Variscan orogen of SW Iberia: Dense wide-angle seismic reflection data

    Science.gov (United States)

    Palomeras, I.; Carbonell, R.; Flecha, I.; Simancas, F.; Ayarza, P.; Matas, J.; MartíNez Poyatos, D.; Azor, A.; GonzáLez Lodeiro, F.; PéRez-Estaún, A.

    2009-02-01

    Two wide-angle seismic transects have been acquired across the SW Iberian Massif. They crossed three major geological zones (South Portuguese Zone, Ossa-Morena Zone, and Central Iberian Zone), with their tectonic contacts and the Pyrite Belt being of greatest interest. A total of 690 digital seismic recording instruments (650 Texans and 40 Reftek 3 component units) from the IRIS-PASSCAL Instrument Pool were used. The transects (A and B) are each approximately 300 km long and consist of 3 and 6 shot points, respectively, with an approximately 60-km shot point interval. The charge sizes range from 1000 kg at the edges to 500 kg at the center. These recently acquired experiments were designed to provide velocity constraints on the lithosphere and to complement the previously acquired normal incidence seismic profile IBERSEIS. Both data sets are part of the SW Iberia project, which was developed within the EUROPROBE program and designed to address fundamental questions about the nature and dynamics of the Variscan lithosphere. The acquisition parameters provide closely spaced wide-angle seismic images of the lithosphere beneath SW Iberia. In transect A, the station spacing was on average 400 m, while along transect B, the receiver spacing was approximately 150 m. Because of this close trace spacing, the lateral continuity of the seismic arrivals is greatly improved. Frequency analysis revealed that the recorded events feature relatively low frequencies (6-25 Hz). After processing, the shot records show high-amplitude and well-defined arrivals. The interpreted PmP arrival, located at approximately 11 s (normal incidence traveltime), is characterized by high amplitude and relatively low frequency (6-12 Hz). A well-defined Pn arrival appears at offsets beyond 120 km. At far offsets greater than 180 km, an upper mantle reflection is observed. Furthermore, within the upper crust, the shots records feature a relatively high-velocity arrival, located at 4-5-s normal incidence

  7. Rifting in the Northern Tyrrhenian Sea: Results from a combined wide-angle and multichannel seismic study

    Science.gov (United States)

    Möller, Stefan; Grevemeyer, Ingo; Ranero, Cesar R.; Berndt, Christian; Klaeschen, Dirk; Sallares, Valenti; Zitellini, Nevio; de Franco, Roberto

    2013-04-01

    Extension in the continental lithosphere leads to the formation of rift basins or finally to passive continental margins where plates fully broke apart. The extensional processes at basins and passive margins are still not fully understood. One of the reasons is that the observed amount of crustal thinning is often much higher than the horizontal extension in the brittle upper crust that can be accounted by faulting. Moreover, conjugated margins are often observed to be asymmetric in tectonic style. Regarding these objective we present an analysis of two W-E striking multichannel- and wide-angle seismic sections from the Northern Tyrrhenian Sea. The new data were acquired onboard the Spanish R/V Sarmiento de Gamboa and Italian R/V Urania in spring 2010, within the framework of the MEDOC project. The lines cross the basin from the Corsica and Sardinia Margins towards the conjugated Latium and Campania Margins (Italy). The transects are divided in four zones distinguishable in tectonic style, velocity distribution, heat-flow and crustal thickness: 1) The deep sedimentary Corsica and Sardinia basins in the West which formed during Oligocene (~30 Ma) and reveal a fan-shaped sedimentary infill that is sealed by a Messinian erosional unconformity on top (~5-7 Ma). 2) Large rotated blocks bounding the deepest sub-basins along the entire transects and contain Messinian syn-tectonic sediments. 3) A zone of highly fractured continental crust broadens to the south and is indicated by a high number of faults and coincident with a velocity reduction. Furthermore, magmatic activity during Pliocene age in the southern line is evident in the southern line. 4) Flat summits at the Latium Margin indicate that this zone was above seal-level during rifting whereas the southern region was sub-sealevel. Faults cutting the seafloor indicate recent tectonic activity. To quantify the amount of horizontal extension we identified pre-, syn-, and post-tectonic sedimentary units in the northern

  8. Rifting in the Northern Tyrrhenian Sea: Results from a combined wide-angle and multichannel seismic study

    Science.gov (United States)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; de Franco, R.

    2012-12-01

    Extension in the continental lithosphere leads to the formation of rift basins or finally to passive continental margins where plates fully broke apart. The extensional processes at basins and passive margins are still not fully understood. One of the reasons is that the observed amount of crustal thinning is often much higher than the horizontal extension in the brittle upper crust that can be accounted by faulting. Regarding this objective we present an analysis of two W-E striking depth-migrated multichannel- and wide-angle seismic sections from the Northern Tyrrhenian Sea. The new data were acquired onboard the Spanish R/V Sarmiento de Gamboa and Italian R/V Uraniain spring 2010, within the framework of the MEDOC project. The lines cross the basin from the Corsica and Sardinia margins towards the conjugated Latium/Campania margins (Italy). Along the transects we found two distinct domains distinguishable in tectonic style, heat-flow and crustal thickness: 1) The deep sedimentary Corsica and Sardinia basins in the West which formation started in the Oligocene (~30 Ma) and reveal a fan-shaped sedimentary infill with the Messinian erosional unconformity on top (~5-7 Ma) and 2) rifted crystalline continental crust expressed by horst and graben structures towards the East. These two domains are separated by a deep reaching (~10 km) and westward dipping fault/thrust complex. To quantify the amount of horizontal extension we identified pre-, syn-, and post-tectonic sedimentary units in the northern line A-B (Figure 1), calculated the relative extension factor by large faults as well as balancing the length of the pre-tectonic basement. The Messinian reflector can be well identified throughout the complete section and is therefore an excellent time-marker within the syn-tectonic sequence. The syn-tectonic sequence is limited by a reflector of Pliocene age. The above lying Pleistocene to Quaternary sediments are undisturbed and identified as the post-tectonic sequence

  9. Short-range order in Fe-based metallic glasses: Wide-angle X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Babilas, Rafał, E-mail: rafal.babilas@polsl.pl [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, Gliwice (Poland); Hawełek, Łukasz [Institute of Non-Ferrous Metals, Gliwice (Poland); A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland); Burian, Andrzej [A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland)

    2014-11-15

    The local atomic structure of the Fe{sub 80}B{sub 20}, Fe{sub 70}Nb{sub 10}B{sub 20} and Fe{sub 62}Nb{sub 8}B{sub 30} glasses prepared in the form of ribbons has been studied by wide-angle X-ray scattering. Structural information about the amorphous ribbons has been derived from analysis of the radial distribution functions using the least-squares curve-fitting method. The obtained structural parameters indicate that Fe–Fe, Fe–B, Fe–Nb and Nb–B contributions are involved in the near-neighbor coordination spheres. The possible similarities of the local atomic arrangement in the investigated glasses and the crystalline Fe{sub 3}B, Fe{sub 23}B{sub 6} and bcc Fe structures are also discussed. - Graphical abstract: Pair distribution functions (a) and best-fit model and experimental radial distribution functions for Fe{sub 80}B{sub 20} (b), Fe{sub 70}Nb{sub 10}B{sub 20} (c) and Fe{sub 62}Nb{sub 8}B{sub 30} (d) metallic glasses. - Highlights: • The short-range ordering in the Fe-based metallic glasses is presented. • The results of RDF function have been analyzed using the least-squares method. • The Fe–Fe, Fe–B, Fe–Nb or Nb–B contributions are involved in coordination spheres. • The structural unit is distorted triangular prism containing B, Fe or Nb atoms. • Similarities of atomic arrangement in glassy and crystalline structures are discussed.

  10. Constaints on the nature of the SW-Iberia crust from wide-angle P- and S-velocity models

    Science.gov (United States)

    Palomeras, I.; Marti, D.; Carbonell, R.; Ayarza, P.; Simancas, F.; Martinez-Poyatos, D.; Azor, A.; Lodeiro, F.; Perez-Estaun, A.

    2009-12-01

    The SW-Iberian Peninsula was studied with the two wide-angle seismic reflection transects acquired in 2003. Both transects cross the three tectonic provinces in the area that are part of the Variscan Belt: South Portuguesse Zone (SPZ), Ossa-Morena Zone (OMZ) and Central Iberia Zone (CIZ). The data were acquired by 650 vertical component seismographs (TEXANS seismic recorders) from the IRIS-PASSCAL Instrument Center, using explosive sources with charge sizes ranging from 500 to 1000 kg. Both Transects, A and B, are, approximately, 300 km long with station spacing of 400 m and 150 m respectively. The relatively small station spacing favored the lateral correlation of the seismic events and provided resolution enough for the identification of shear-waves arrivals. The most prominent S-wave phase recorded by the vertical component sensors corresponds to the SmS which is nearly horizontal for a velocity reduction of 4600 m/s. This phase can be followed up to normal incidence at 18 s ttwt. Two S-wave velocity models have been derived by iterative forward modeling to provide constraints on the nature of the deep crust beneath the Variscan of SW-Iberia. P and S velocity models show a high velocity area at mid crustal levels, that has been interpreted as a mafic intrusion. Vp/Vs relationship has been also calculated to constraint the crustal composition. The resulting images present a mid- to lower-crust with a Vp/Vs > 1.73 that implies a crust with a high content in mafic components.

  11. S-waves velocity model for the SW-Iberia derived from the IBERSEIS wide-angle seismic reflection transects

    Science.gov (United States)

    Palomeras, I.; Marti, D.; Carbonell, R.; Ayarza, P.; Simancas, F.; Martinez-Poyatos, D.; Azor, A.; Gonzalez-Lodeiro, F.; Perez-Estaun, A.

    2009-04-01

    The IBERSEIS wide-angle seismic reflection transects acquired in 2003 in SW-Iberia Peninsula provided constraints on the P-wave seismic velocity structure across the three tectonic provinces in the area: the South Portuguesse Zone (SPZ), the Ossa-Morena Zone (OMZ) and the Central Iberia Zone (CIZ). These data were acquired by 650 vertical component seismographs (TEXAN seismic recorders) from the IRIS-PASSCAL Instrument center, using explosive sources with charge sizes ranging from 500 to 1000 kg. Both transects A and B are, approximately, 300 km long with a station spacing of 400 m and of 150 m respectively. The relatively small station spacing favored the lateral correlation of the seismic events and provided enough resolution for the identification of shear-wave arrivals. The most prominent S-wave phase recorded by the vertical component sensors corresponds to the SmS which is nearly horizontal for a velocity reduction of 4600 m/s. This phase can even be followed up to near vertical incidence at 18 s(twtt). A few S-wave crustal arrivals can be also identified, although at small offsets they interfere with the previous P-wave arrivals. The Sn phase can be observed at very far offsets providing additional constraints on the nature of the shallow subcrustal mantle. Furthermore, slant stacks of the shot gathers (tau-p sections) reveal the existing of PS energy. PS phases are more difficult to identify in the shot gathers. Finally, a preliminary S-wave velocity model has been derived by iterative forward modeling to provide additional constraints on the nature of the deep crust and upper mantle beneath the Variscan of SW-Iberia.

  12. Mesospheric Temperatures and Meteoric Dust Detection based on Wide-angle Polarization Measurements of the Twilight Sky

    Science.gov (United States)

    Ugolnikov, Oleg; Maslov, Igor

    The work is based on fast all-sky polarization measurements of the twilight background started in 2011 in central Russia (55.2 deg N, 37.5 deg E). The data is used to build the polarization scattering functions of the mesospheric medium depending on the altitude. These functions can be used for dust scattering detection and study. The problem is hard to be solved by space or lidar measurements providing the data just for one definite scattering angle, however, the twilight technique is the least expensive method for the mesospheric research. The method described in (Ugolnikov, Maslov, 2013) is used to separate single and multiple scattering, which is the basic problem of the twilight remote sensing. Light scattering in the mesosphere is turned out to be Rayleigh-dominated for the most part of observation dates. This allows finding the altitude dependencies of pressure and the temperatures in the mesosphere. The values of temperature are in good agreement with TIMED/SABER and EOS Aura/MLS space limb data for nearby locations. Admixture of dust scattering was occasionally observed, reaching the maximum during the Perseids meteor shower activity in 2013. The scattering functions analysis gives the value of moderated dust layer in the mesosphere (81-83 km) and helps to estimate the particles size. The work is supported by Russian Foundation for Basic Research, grant 12-05-00501-a. References Ugolnikov O.S., Maslov I.A. Summer mesosphere temperature distribution from wide-angle polarization measurements of the twilight sky // Journal of Atmospheric and Solar-Terrestrial Physics, V.105-106, P.8-14, 2013.

  13. The crustal structure of Beira High, central Mozambique-Combined investigation of wide-angle seismic and potential field data

    Science.gov (United States)

    Mueller, Christian Olaf; Jokat, Wilfried; Schreckenberger, Bernd

    2016-06-01

    The timing and geometry of the initial Gondwana break-up between Africa and East Antarctica is still poorly known due to missing information about the continent-ocean boundaries along the rifted margins. In this context, the Beira High off central Mozambique forms a critical geological feature of uncertain crustal fabric. Based on new wide-angle seismic and potential field data across Beira High a P-wave velocity model, supported by amplitude and gravity modelling, provides constraints on the crustal composition of this area. In the Mozambique Basin mainly normal oceanic crust of 5.5-7 km thickness with velocities of 6.5-7.0 km/s in the lower crust is present. A sharp transition towards Beira High marks the continent-ocean boundary. Here the crust thickens to 23 km at maximum. A small velocity-depth gradient and a constant increase in velocity with basal velocities of maximum 7.0 km/s are in good agreement with typical velocities of continental crust and continental fragments. The density model indicates the existence of felsic material in greater depths and supports a fabric of stretched, but highly intruded continental crust below Beira High. A gradual decrease in crustal thickness characterizes the transition towards the Mozambican shelf area. Here, in the Zambezi Delta Depression 12 km of sediments cover the underlying 7 km thick crust. The presence of a high-velocity lower crustal body with velocities of 7.1-7.4 km/s indicates underplated, magmatic material in this part of the profile. However, the velocity structure in the shelf area allows no definite interpretation because of the experimental setup. Thus, the crustal nature below the Zambezi Delta and consequently the landward position of the continent-ocean boundary remains unknown. The difference in stretching below the margins of Beira High suggests the presence of different thinning directions and a rift jump during the early rifting stage.

  14. Brief Introduction on the Korea-China Collaborative Research on the Wide-angle Seismic Experiment of the Yellow Sea

    Science.gov (United States)

    Kim, J.; Kim, K. H.; Kim, H. J.; Hao, T.; Zhang, X.

    2016-12-01

    Small to moderate earthquakes occurred in the Yellow Sea, such as Seogyuckryulbi-do earthquake (ML 5.1, April 1, 2014) and Heuksan-do earthquake (ML 4.9, April 21, 2013). Although the earthquakes occurred in a region of apparent low seismicity, they attracted much attention for the seismic hazards and rose questions about the reevaluation the seismicity of the Yellow Sea. Although several tectonic models have been proposed from the observations in China and Korea, it is still not clear which one can answer the tectonic problem. Furthermore, the seismicity of the Yellow Sea has been rarely investigated since the region is located outside seismic networks. It is suspected that the seismicity of the region is related to basin boundary faults created by rifting and tectonic inverting. In order to evaluate earthquake hazard of the Yellow Sea, it is required to identify spatial distribution of the faults. In this study, a deep seismic profile was carried out using ocean bottom seismometers (OBS's) to investigate the crust and upper mantle structure beneath the Yellow Sea and their relationship with shallower structures. The deep seismic profile was conducted by M/V Discoverer and R/V Eardo from June 21 to July 3, 2016. The air-gun array of 6,640 cu. in. shot along the 405 km profile across the Yellow Sea, which was recorded by 31 OBS's at a 13.5 km spacing. Besides, 10 temporary land stations were also installed onshore along the profile. This Korea-China collaborative wide-angle seismic experiment was first time across the Yellow Sea. Through this study, it is expected that Korea and China would build a credible cooperation on the study of the Yellow Sea region in future, and it's helpful to verify previously proposed tectonic evolution models for northeastern Asia including the Yellow Sea.

  15. Monte Carlo approach to assess the uncertainty of wide-angle layered models: Application to the Santos Basin, Brazil

    Science.gov (United States)

    Loureiro, Afonso; Afilhado, Alexandra; Matias, Luís; Moulin, Maryline; Aslanian, Daniel

    2016-06-01

    In the Santos Basin (Brazil), two parallel wide-angle refraction profiles show different crustal structures. One shows moderate crustal velocity gradient, and a clear Moho with topography. The other has an anomalous velocity zone, and no clear Moho reflections. This has large implications on the geological and geodynamical interpretation of the basin. Model uncertainties must be excluded as a source of these differences. We developed VMONTECARLO, a tool to assess model uncertainty of layered velocity models using a Monte Carlo approach and simultaneous parameter perturbation using all picked refracted and reflected arrivals. It gives insights into the acceptable geological interpretations allowed by data and model uncertainty through velocity-depth plots that provide: a) the velocity-depth profile range that is consistent with the travel times; b) the random model that provides the best fit, keeping most of the observations covered by ray-tracing; c) insight into valid models dispersion; d) main model features unequivocally required by the travel times, e.g., first-order versus second-order discontinuities, and velocity gradient magnitudes; e) parameter value probability distribution histograms. VMONTECARLO is seamlessly integrated into a RAYINVR-based modelling work-flow, and can be used to assess final models or sound the solution space for alternate models, and is also capable of evaluating forward models without the need for inversion, thus avoiding local minima that may trap the inversion algorithms and providing information for models still not well-parametrised. Results for the Brazilian models show that the imaged structures are indeed geologically different and are not due to different interpretations of the same features within the model uncertainty bounds. These differences highlight the strong heterogeneity of the crust in the middle of the Santos Basin, where the rift is supposed to have failed.

  16. Next-generation seismic experiments: wide-angle, multi-azimuth, three-dimensional, full-waveform inversion

    Science.gov (United States)

    Bell, Rebecca; Morgan, Joanna; Warner, Michael

    2016-04-01

    There are many outstanding plate-tectonic scale questions that require us to know information about sub-surface physical properties, for example ascertaining the geometry and location of magma chambers and estimating the effective stress along plate boundary faults. These important scientific targets are often too deep, impractical and expensive for extensive academic drilling. Full-waveform inversion (FWI) is an advanced seismic imaging technique that has recently become feasible in three dimensions, and has been widely adopted by the oil and gas industry to image reservoir-scale targets at shallow-to-moderate depths. In this presentation we explore the potential for 3-D FWI, when combined with appropriate marine seismic acquisition, to recover high-resolution high-fidelity P-wave velocity models for sub-sedimentary targets within the crystalline crust and uppermost mantle. Using existing geological and geophysical models, we construct P-wave velocity models over three potential sub-sedimentary targets: the Soufrière Hills Volcano on Montserrat and its associated crustal magmatic system, the downgoing oceanic plate beneath the Nankai subduction margin, and the oceanic crust-uppermost mantle beneath the East Pacific Rise mid-ocean ridge. We use these models to generate realistic multi-azimuth 3-D synthetic seismic data, and attempt to invert these data to recover the original models. We explore the resolution and accuracy, sensitivity to noise and acquisition geometry, ability to invert elastic data using acoustic inversion codes, and the trade-off between low frequencies and starting velocity model accuracy. We will show that FWI applied to multi-azimuth, refracted, wide-angle, low-frequency data can resolve features in the deep crust and uppermost mantle on scales that are significantly better than can be achieved by any other geophysical technique, and that these results can be obtained using relatively small numbers (60-90) of ocean-bottom receivers combined

  17. Crustal thinning in the northern Tyrrhenian Rift: Insights from multichannel and wide-angle seismic data across the basin

    Science.gov (United States)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; Franco, R.

    2014-03-01

    Extension of the continental lithosphere leads to the formation of rift basins or rifted continental margins if breakup occurs. Seismic investigations have repeatedly shown that conjugate margins have asymmetric tectonic structures and different amount of extension and crustal thinning. Here we compare two coincident wide-angle and multichannel seismic profiles across the northern Tyrrhenian rift system sampling crust that underwent different stages of extension from north to south and from the flanks to the basin center. Tomographic inversion reveals that the crust has thinned homogeneously from ~24 km to ~17 km between the Corsica Margin and the Latium Margin implying a β factor of ~1.3-1.5. On the transect 80 km to the south, the crust thinned from ~24 km beneath Sardinia to a maximum of ~11 km in the eastern region near the Campania Margin (β factor of ~2.2). The increased crustal thinning is accompanied by a zone of reduced velocities in the upper crust that expands progressively toward the southeast. We interpret that the velocity reduction is related to rock fracturing caused by a higher degree of brittle faulting, as observed on multichannel seismic images. Locally, basalt flows are imaged intruding sediment in this zone, and heat flow values locally exceed 100 mW/m2. Velocities within the entire crust range 4.0-6.7 km/s, which are typical for continental rocks and indicate that significant rift-related magmatic underplating may not be present. The characteristics of the pre-tectonic, syn-tectonic and post-tectonic sedimentary units allow us to infer the spatial and temporal evolution of active rifting. In the western part of the southern transect, thick postrift sediments were deposited in half grabens that are bounded by large fault blocks. Fault spacing and block size diminish to the east as crustal thinning increases. Recent tectonic activity is expressed by faults cutting the seafloor in the east, near the mainland of Italy. The two transects show

  18. Wide-angle seismic survey in the trench-outer rise region of the central Japan Trench

    Science.gov (United States)

    Fujie, G.; Kodaira, S.; Iwamaru, H.; Shirai, T.; Dannowski, A.; Thorwart, M.; Grevemeyer, I.; Morgan, J. P.

    2015-12-01

    Dehydration process within the subducting oceanic plate and expelled water from there affect various subduction-zone processes, including arc volcanism and generation of earthquakes. This implies that the degree of hydration within the incoming oceanic plate just prior to subduction might be a key control factor on the regional variations in subduction zone processes like interplate earthquakes and arc volcanism. Recent advances in seismic structure studies in the trench-outer rise region of the Japan Trench have revealed that seismic velocities within the incoming oceanic plate become lower owing to the plate bending-related faulting, suggesting the hydration of the oceanic plate. If the degree of the oceanic plate hydration is one of key factors controlling the regional variations of the interplate earthquakes, the degree of the oceanic plate hydration just prior to subduction is expected to show the along-trench variation because the interplate seismicity in the forearc region of the Japan Trench show along-trench variations. However, we cannot discuss the along-trench variation of the incoming plate structure because seismic structure studies have been confined only to the northern Japan Trench so far.In 2014 and 2015, JAMSTEC and GEOMAR conducted wide-angle seismic surveys in the trench-outer rise region of the central Japan Trench to reveal the detailed seismic structure of the incoming oceanic plate. The western extension of our survey line corresponds to the epicenter of the 2011 M9 Tohoku earthquakes. We deployed 88 Ocean Bottom Seismometers (OBSs) at intervals of 6 km and shot a tuned air-gun array of R/V Kairei at 200 m spacing. In this presentation, we will show the overview of our seismic survey and present seismic structure models obtained by the data of mainly 2014 seismic survey together with the several OBS data from 2015 survey. The preliminary results show P-wave velocity (Vp) within the oceanic crust and mantle decreases toward the trench axis

  19. Application of wide-angle scattering techniques using microfocus X-ray beam to investigate structural variation in polymer laminates

    Energy Technology Data Exchange (ETDEWEB)

    Bhagat, R

    1999-09-01

    Experiments have been conducted at the European Synchrotron Radiation Facility (ESRF) at Grenoble (France). The Synchrotron Radiation used provides a monochromatic X-ray beam with brilliance and flux density far greater than is attainable with a rotating anode laboratory source. In addition the glass capillary optics used, increases the flux density at the capillary exit as well as providing a sub-micron beam which coupled with the XYZ stage allows data to be collected at high spatial resolution. A Photonics Science CCD detector coupled to a frame grabber has permitted data to be collected at high temporal resolution (40ms) as well as displaying the data in real-time mode. Software used during analysis was used to reduce the amount of spurious signals due to background scatter as well as enable results to be calculated with a high degree of confidence. The aim of this research was to investigate the effect of industrial processing parameters in production of PET laminates and PEN films. Wide Angle X-ray Scattering (WAXS) patterns have been collected, using a beam size of 2.3 {mu}m at intervals of 1 {mu}m through the sample. Crystallite sizeand orientation analyses on patterns collected have been used as an indication of changes in the structural morphology through the thickness of the films. Data analyses of PET films show that biaxial stretching of films is very complex and depending on the parameters at each stage of the process, the final film has very different characteristics. It has been shown that the effects of draw ratio and draw temperature in the forward direction results in a range of crystallite sizes that lead to either crystal fracture or reorientation of the crystallites as the dominant process in the transverse draw. The effects of annealing can also lead to crystal welding or melting and re-crystallisation depending on the amount of time spent in the lamination process. Data analyses of PEN films show that the choice of parameters in biaxial

  20. 23-gauge vitrectomy assisted by combined endoscopy and a wide-angle viewing system for retinal detachment with severe penetrating corneal injury: a case report

    Directory of Open Access Journals (Sweden)

    Morishita S

    2011-12-01

    Full Text Available Seita Morishita, Mihori Kita, Shin Yoshitake, Miou Hirose, Hideyasu OhDepartment of Ophthalmology, Hyogo Prefectural Amagasaki Hospital, Amagasaki, Hyogo, JapanBackground: We report a case of traumatic retinal detachment in an eye with severe corneal opacity that was successfully treated using 23 gauge (G transconjunctival vitrectomy assisted by endoscope and a wide-angle viewing system.Case presentation: A 22-year-old Japanese man was referred to our hospital with the suspicion of traumatic retinal detachment of the right eye, 1 month after an open globe eye injury due to fireworks. At the time of his first visit, his best-corrected visual acuity was hand motion in the right eye. A 23 G three port pars plana vitrectomy was conducted in combination with ophthalmic endoscope and a wide-angle viewing system. Endoscopy revealed a retinal detachment in the inferior quadrant with tiny retinal breaks. Primary reattachment of the retina was achieved by tamponade of SF6 gas. Five months after the vitrectomy, penetrating keratoplasty was performed and visual acuity recovered to 0.02. Optical coherent tomography revealed thinning of the retina, which might be the cause of the remaining poor vision.Conclusion: 23 G vitrectomy assisted by combined endoscopy and a wide-angle viewing system could be advantageous in managing visualization constraints due to penetrating trauma.Keywords: penetrating injury, vitrectomy, endoscope, wide angle viewing system, 23 gauge vitrectomy

  1. Combined in situ small and wide angle X-ray scattering studies of TiO2 nano-particle annealing to 1023 K

    DEFF Research Database (Denmark)

    Kehres, Jan; Andreasen, Jens Wenzel; Krebs, Frederik C

    2010-01-01

    Combined in situ small- and wide-angle X-ray scattering (SAXS/WAXS) studies were performed in a recently developed laboratory setup to investigate the dynamical properties of dry oleic acid-capped titanium dioxide nanorods during annealing in an inert gas stream in a temperature interval of 298-1...

  2. Crustal architecture and deep structure of the Namibian passive continental margin around Walvis Ridge from wide-angle seismic data

    Science.gov (United States)

    Behrmann, Jan H.; Planert, Lars; Jokat, Wilfried; Ryberg, Trond; Bialas, Jörg; Jegen, Marion

    2013-04-01

    The opening of the South Atlantic ocean basin was accompanied by voluminous magmatism on the conjugate continental margins of Africa and South America, including the formation of the Parana and Entendeka large igneous provinces (LIP), the build-up of up to 100 km wide volcanic wedges characterized by seaward dipping reflector sequences (SDR), as well as the formation of paired hotspot tracks on the rifted African and South American plates, the Walvis Ridge and the Rio Grande Rise. The area is considered as type example for hotspot or plume-related continental break-up. However, SDR, and LIP-related features on land are concentrated south of the hotspot tracks. The segmentation of the margins offers a prime opportunity to study the magmatic signal in space and time, and investigate the interrelation with rift-related deformation. A globally significant question we address here is whether magmatism drives continental break-up, or whether even rifting accompanied by abundant magmatism is in response to crustal and lithospheric stretching governed by large-scale plate kinematics. In 2010/11, an amphibious set of wide-angle seismic data was acquired around the landfall of Walvis Ridge at the Namibian passive continental margin. The experiments were designed to provide crustal velocity information and to investigate the structure of the upper mantle. In particular, we aimed at identifying deep fault zones and variations in Moho depth, constrain the velocity signature of SDR sequences, as well as the extent of magmatic addition to the lower crust near the continent-ocean transition. Sediment cover down to the igneous basement was additionally constrained by reflection seismic data. Here, we present tomographic analysis of the seismic data of one long NNW oriented profile parallel to the continental margin across Walvis Ridge, and a second amphibious profile from the Angola Basin across Walvis Ridge and into the continental interior, crossing the area of the Etendeka

  3. Optimization of the Orbiting Wide-angle Light Collectors (OWL) Mission for Charged-Particle and Neutrino Astronomy

    CERN Document Server

    Krizmanic, John F; Streitmatter, Robert E

    2013-01-01

    OWL uses the Earth's atmosphere as a vast calorimeter to fully enable the emerging field of charged-particle astronomy with high-statistics measurements of ultra-high-energy cosmic rays (UHECR) and a search for sources of UHE neutrinos and photons. Confirmation of the Greisen-Zatsepin-Kuzmin (GZK) suppression above ~4 x 10^19 eV suggests that most UHECR originate in astrophysical objects. Higher energy particles must come from sources within about 100 Mpc and are deflected by ~1 degree by predicted intergalactic/galactic magnetic fields. The Pierre Auger Array, Telescope Array and the future JEM-EUSO ISS mission will open charged-particle astronomy, but much greater exposure will be required to fully identify and measure the spectra of individual sources. OWL uses two large telescopes with 3 m optical apertures and 45 degree FOV in near-equatorial orbits. Simulations of a five-year OWL mission indicate ~10^6 km^2 sr yr of exposure with full aperture at ~6 x 10^19 eV. Observations at different altitudes and sp...

  4. Optimization of the Orbiting Wide-Angle Light Collectors (OWL) Mission for Charged-Particle and Neutrino Astronomy

    Science.gov (United States)

    Krizmanic, John F.; Mitchell, John W.; Streitmatter, Robert E.

    2013-01-01

    OWL [1] uses the Earth's atmosphere as a vast calorimeter to fully enable the emerging field of charged-particle astronomy with high-statistics measurements of ultra-high-energy cosmic rays (UHECR) and a search for sources of UHE neutrinos and photons. Confirmation of the Greisen-Zatsepin-Kuzmin (GZK) suppression above approx. 4 x 10(exp 19) eV suggests that most UHECR originate in astrophysical objects. Higher energy particles must come from sources within about 100 Mpc and are deflected by approx. 1 degree by predicted intergalactic/galactic magnetic fields. The Pierre Auger Array, Telescope Array and the future JEM-EUSO ISS mission will open charged-particle astronomy, but much greater exposure will be required to fully identify and measure the spectra of individual sources. OWL uses two large telescopes with 3 m optical apertures and 45 degree FOV in near-equatorial orbits. Simulations of a five-year OWL mission indicate approx. 10(exp 6) sq km/ sr/ yr of exposure with full aperture at approx. 6 x 10(exp 19) eV. Observations at different altitudes and spacecraft separations optimize sensitivity to UHECRs and neutrinos. OWL's stereo event reconstruction is nearly independent of track inclination and very tolerant of atmospheric conditions. An optional monocular mode gives increased reliability and can increase the instantaneous aperture. OWL can fully reconstruct horizontal and upward-moving showers and so has high sensitivity to UHE neutrinos. New capabilities in inflatable structures optics and silicon photomultipliers can greatly increase photon sensitivity, reducing the energy threshold for n detection or increasing viewed area using a higher orbit. Design trades between the original and optimized OWL missions and the enhanced science capabilities are described.

  5. A quantitative differentiation method for plastic bags by wide angle X-ray diffraction for tracing the source of illegal drugs.

    Science.gov (United States)

    Causin, Valerio; Marega, Carla; Carresi, Pietro; Schiavone, Sergio; Marigo, Antonio

    2007-05-03

    Thirty-three shopping bags, commonly encountered in the packaging of drug doses, were characterized by wide angle X-ray diffraction (WAXD). Using this single technique, without sample preparation, nearly all the considered samples could be differentiated, achieving a discriminating power of 0.992. The rather large degree of variability existing in grocery bags, even though they are mass produced, was shown, confirming that these items can be useful in tracing the source of illicit drug doses.

  6. Penetration route of functional molecules in stratum corneum studied by time-resolved small- and wide-angle x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Hatta, Ichiro; Ohta, Noboru; Yagi, Naoto [Japan Synchrotron Radiation Research Institute/SPring-8 (Japan); Nakazawa, Hiromitsu [Department of Physics, Kwansei Gakuin University (Japan); Obata, Yasuko [Department of Pharmaceutics, Hoshi University (Japan); Inoue, Katsuaki, E-mail: hatta@spring8.or.jp [Diamond Light Source (United Kingdom)

    2011-01-01

    We studied effects of functional molecules on corneocytes in stratum corneum using time-resolved small- and wide-angle x-ray diffraction after applying a functional molecule. From these results it was revealed that in the stratum corneum a typical hydrophilic molecule, ethanol, penetrates via the transcellular route and on the other hand a typical hydrophobic molecule, d-limonene, penetrates via the intercellular route.

  7. Femtosecond Laser Fabrication of Cavity Microball Lens (CMBL) inside a PMMA Substrate for Super-Wide Angle Imaging.

    Science.gov (United States)

    Zheng, Chong; Hu, Anming; Kihm, Kenneth D; Ma, Qian; Li, Ruozhou; Chen, Tao; Duley, W W

    2015-07-01

    Since microlenses have to date been fabricated primarily by surface manufacturing, they are highly susceptible to surface damage, and their microscale size makes it cumbersome to handle. Thus, cavity lenses are preferred, as they alleviate these difficulties associated with the surface-manufactured microlenses. Here, it is shown that a high repetition femtosecond laser can effectively fabricate cavity microball lenses (CMBLs) inside a polymethyl methacrylate slice. Optimal CMBL fabrication conditions are determined by examining the pertinent parameters, including the laser processing time, the average irradiation power, and the pulse repetition rates. In addition, a heat diffusion modeling is developed to better understand the formation of the spherical cavity and the slightly compressed affected zone surrounding the cavity. A micro-telescope consisting of a microscope objective and a CMBL demonstrates a super-wide field-of-view imaging capability. Finally, detailed optical characterizations of CMBLs are elaborated to account for the refractive index variations of the affected zone. The results presented in the current study demonstrate that a femtosecond laser-fabricated CMBL can be used for robust and super-wide viewing micro imaging applications.

  8. First results on the crustal structure of the Natal Valley from combined wide-angle and reflection seismic data (MOZ3/5 cruise), South Mozambique Margin.

    Science.gov (United States)

    Leprêtre, Angélique; Verrier, Fanny; Evain, Mikael; Schnurle, Philippe; Watremez, Louise; Aslanian, Daniel; de Clarens, Philippe; Dias, Nuno; Afilhado, Alexandra; Leroy, Sylvie; d'Acremont, Elia; Castilla, Raymi; Moulin, Maryline

    2017-04-01

    The Natal valley (South Mozambique margin) is a key area for the understanding of the SW Indian Ocean history since the Gondwana break-up, and widely, the structure of a margin system at the transition between divergent and strike-slip segments. As one part of the PAMELA project (PAssive Margins Exploration Laboratories), conducted by TOTAL, IFREMER, in collaboration with Université de Bretagne Occidentale, Université Rennes 1, Université Pierre and Marie Curie, CNRS et IFPEN, the Natal Valley and the East Limpopo margin have been explored during the MOZ3/5 cruise (2016), conducted onboard the R/V Pourquoi Pas?, through the acquisition of 7 wide-angle profiles and coincident marine multichannel (720 traces) seismic as well as potential field data. Simultaneously, land seismometers were deployed in the Mozambique coastal plains, extending six of those profiles on land for about 100 km in order to provide information on the onshore-offshore transition. Wide-angle seismic data are of major importance as they can provide constrains on the crustal structure of the margin and the position of the continent-ocean boundary in an area where the crustal nature is poorly known and largely controversial. The aim of this work is to present the first results on the crustal structure from P-waves velocity modeling along two perpendicular MZ1 & MZ7 wide-angle profiles crossing the Natal Valley in an E-W and NNW-SSE direction respectively, which reveal a crust up to 30 km thick below the Natal Valley and thus raises questions of a purely oceanic origin of the Valley. The post-doc of Angélique Leprêtre is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project.

  9. 大视场高分辨力星载成像光谱仪光学系统设计%Optical System Design of Wide-Angle and High-Resolution Spaceborne Imaging Spectrometer

    Institute of Scientific and Technical Information of China (English)

    薛庆生; 黄煜; 林冠宇

    2011-01-01

    大视场、高分辨力星载成像光谱仪已成为空间遥感的迫切需求.根据大视场、高分辨力的研究目标,提出了先视场分离分光再用分色片分光的设计方法,分析了视场分离分光的原理.设计了一个全反射式星载成像光谱仪光学系统,该系统由指向镜、11.42°远心离轴三反消像散(TMA)前置望远系统和4个Offner凸面光栅光谱成像系统组成,通过恰当选择4个光谱成像系统的变倍比来实现2种探测器的匹配.运用光学设计软件CODE V对成像光谱仪调制系统进行了光线追迹和优化,并对设计结果进行了分析.分析结果表明,光学系统在各个谱段的光学传递函数均达到0.7以上,完全满足设计指标要求;同时证明了设计方法是可行的.%Space remote sensing urgently requires wide-angle and high-resolution spaceborne imaging spectrometer. According to the research objective of wide angle and high resolution, the design method of firstly dividing field of view (FOV) and secondly dividing beam using dichroscope is developed. The principle of dividing FOV is analyzed. A reflective spaceborne imaging spectrometer is designed, which is composed of a pointing mirror, a 11.42° telecentric off-axis three-mirror anastigmatic (TMA) telescope and four Offner convex grating spectral imaging systems. The proper magnification is chosen for each spectral imaging system to match two types of detectors. Ray tracing and optimization are performed and analyzed by CODE V software. The results demonstrate that the modulation transfer function (MTF) for different spectral bands is more than 0. 7, which satisfies the pre-designed requirement. The design method is proved to be feasible.

  10. New calculations of cross-sections and charge asymmetries for lepton pair production and wide angle Bhabha scattering in e+e- collisions near the Z-peak

    Science.gov (United States)

    Field, J. H.

    1994-03-01

    A new event generator for lepton pair production and wide angle Bhabha scattering, BHAGENE3, is presented. Both electroweak and higher order (beyond O(α) QED corrections are included. Comparisons are made with results from the programs, based on the structure function formalism, ALIBABA, TOPAZ0 and ZFITTER. For the case of the final states l+l-γγ ( l = e, μ, τ) BHAGENE3 results are compared with those of Monte Carlo generators that use the exact O( α2) amplitudes.

  11. Identifying dynamically young galaxy groups via wide-angle tail galaxies: A case study in the COSMOS field at z=0.53

    CERN Document Server

    Oklopcic, A; Giodini, S; Zamorani, G; Birzan, L; Schinnerer, E; Carilli, C L; Finoguenov, A; Lilly, S; Koekemoer, A; Scoville, N Z

    2010-01-01

    We present an analysis of a wide-angle tail (WAT) radio galaxy located in a galaxy group in the COSMOS field at a redshift of z=0.53 (hereafter CWAT-02). We find that the host galaxy of CWAT-02 is the brightest galaxy in the group, although it does not coincide with the center of mass of the system. Estimating a) the velocity of CWAT-02, relative to the intra-cluster medium (ICM), and b) the line-of-sight peculiar velocity of CWAT-02's host galaxy, relative to the average velocity of the group, we find that both values are higher than those expected for a dominant galaxy in a relaxed system. This suggests that CWAT-02's host group is dynamically young and likely in the process of an ongoing group merger. Our results are consistent with previous findings showing that the presence of a wide-angle tail galaxy in a galaxy group or cluster can be used as an indicator of dynamically young non-relaxed systems. Taking the unrelaxed state of CWAT-02's host group into account, we discuss the impact of radio-AGN heating...

  12. Wave images of the crustal structure from refraction and wide-angle reflection migrations along the DOBRE profile (Dnieper-Donets paleorift)

    Science.gov (United States)

    Pylypenko, V. N.; Verpakhovska, O. O.; Starostenko, V. I.; Pavlenkova, N. I.

    2011-07-01

    The DOBRE profile crosses the Donbas Foldbelt that is an uplifted part of the Dnieper-Donets paleorift. The depth to the basement reaches 20 km. The refraction and wide-angle reflection survey was carried out along this 360 km profile with 245 recording stations and 11 shot points (DOBREfraction'99 Working Group et al., 2003). The velocity modeling traced three continual boundaries: the basement surface, the intra-crustal boundary and the Moho. The refraction and wide-angle reflection migrations, applied to the data, enable to reveal some new structural features of the boundaries. It determines a system of faults which divide the basement into several flat segments with stepwise increasing of their depths. In the central part of the profile the intra-crustal boundary is imaged which corresponds to a strong refraction boundary at a depth of 15-25 km. The Moho was traced as a weak boundary at a depth of 35-40 km beneath the Donbas and the crust-mantle transition zone is characterized by thick heterogeneous zone of lens form.

  13. Ultra-wideband, Wide Angle and Polarization-insensitive Specular Reflection Reduction by Metasurface based on Parameter-adjustable Meta-Atoms

    Science.gov (United States)

    Su, Jianxun; Lu, Yao; Zhang, Hui; Li, Zengrui; (Lamar) Yang, Yaoqing; Che, Yongxing; Qi, Kainan

    2017-02-01

    In this paper, an ultra-wideband, wide angle and polarization-insensitive metasurface is designed, fabricated, and characterized for suppressing the specular electromagnetic wave reflection or backward radar cross section (RCS). Square ring structure is chosen as the basic meta-atoms. A new physical mechanism based on size adjustment of the basic meta-atoms is proposed for ultra-wideband manipulation of electromagnetic (EM) waves. Based on hybrid array pattern synthesis (APS) and particle swarm optimization (PSO) algorithm, the selection and distribution of the basic meta-atoms are optimized simultaneously to obtain the ultra-wideband diffusion scattering patterns. The metasurface can achieve an excellent RCS reduction in an ultra-wide frequency range under x- and y-polarized normal incidences. The new proposed mechanism greatly extends the bandwidth of RCS reduction. The simulation and experiment results show the metasurface can achieve ultra-wideband and polarization-insensitive specular reflection reduction for both normal and wide-angle incidences. The proposed methodology opens up a new route for realizing ultra-wideband diffusion scattering of EM wave, which is important for stealth and other microwave applications in the future.

  14. Scalable, "Dip-and-Dry" Fabrication of a Wide-Angle Plasmonic Selective Absorber for High-Efficiency Solar-Thermal Energy Conversion.

    Science.gov (United States)

    Mandal, Jyotirmoy; Wang, Derek; Overvig, Adam C; Shi, Norman N; Paley, Daniel; Zangiabadi, Amirali; Cheng, Qian; Barmak, Katayun; Yu, Nanfang; Yang, Yuan

    2017-08-28

    A galvanic-displacement-reaction-based, room-temperature "dip-and-dry" technique is demonstrated for fabricating selectively solar-absorbing plasmonic-nanoparticle-coated foils (PNFs). The technique, which allows for facile tuning of the PNFs' spectral reflectance to suit different radiative and thermal environments, yields PNFs which exhibit excellent, wide-angle solar absorptance (0.96 at 15°, to 0.97 at 35°, to 0.79 at 80°), and low hemispherical thermal emittance (0.10) without the aid of antireflection coatings. The thermal emittance is on par with those of notable selective solar absorbers (SSAs) in the literature, while the wide-angle solar absorptance surpasses those of previously reported SSAs with comparable optical selectivities. In addition, the PNFs show promising mechanical and thermal stabilities at temperatures of up to 200 °C. Along with the performance of the PNFs, the simplicity, inexpensiveness, and environmental friendliness of the "dip-and-dry" technique makes it an appealing alternative to current methods for fabricating selective solar absorbers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Space Telescope.

    Science.gov (United States)

    National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

    This pamphlet describes the Space Telescope, an unmanned multi-purpose telescope observatory planned for launch into orbit by the Space Shuttle in the 1980s. The unique capabilities of this telescope are detailed, the major elements of the telescope are described, and its proposed mission operations are outlined. (CS)

  16. Thermo-mechanical analysis of ITER first mirrors and its use for the ITER equatorial visible∕infrared wide angle viewing system optical design.

    Science.gov (United States)

    Joanny, M; Salasca, S; Dapena, M; Cantone, B; Travère, J M; Thellier, C; Fermé, J J; Marot, L; Buravand, O; Perrollaz, G; Zeile, C

    2012-10-01

    ITER first mirrors (FMs), as the first components of most ITER optical diagnostics, will be exposed to high plasma radiation flux and neutron load. To reduce the FMs heating and optical surface deformation induced during ITER operation, the use of relevant materials and cooling system are foreseen. The calculations led on different materials and FMs designs and geometries (100 mm and 200 mm) show that the use of CuCrZr and TZM, and a complex integrated cooling system can limit efficiently the FMs heating and reduce their optical surface deformation under plasma radiation flux and neutron load. These investigations were used to evaluate, for the ITER equatorial port visible∕infrared wide angle viewing system, the impact of the FMs properties change during operation on the instrument main optical performances. The results obtained are presented and discussed.

  17. Systematic Structural Change in Selected Rare Earth Oxide Pyrochlores as Determined by Wide-Angle CBED and a Comparison with the Results of Atomistic Computer Simulation

    Science.gov (United States)

    Tabira, Yasunori; Withers, Ray L.; Minervini, Licia; Grimes, Robin W.

    2000-08-01

    An unknown oxygen atom fractional co-ordinate characteristic of the pyrochlore structure type has been determined for selected rare earth zirconate and titanate pyrochlores via a systematic row wide-angle CBED technique and shown to vary systematically with rare earth ion size. In the case of the titanate pyrochlore Gd2Ti2O7, the obtained results contrast with previously published X-ray results. Atomistic computer simulation is used to predict the value of the same parameter for a wide range of oxide pyrochlores. Comparison of calculated values with experimentally determined values shows that the general trends are correctly predicted although there appears to be systematic underestimation of both the observed values (by approximately 0.007) as well as their rate of change with rare earth ion size. Cation anti-site disorder is proposed as the origin of these discrepancies.

  18. Multiaxial deformation of polyethylene and polyethylene/clay nanocomposites: In situ synchrotron small angle and wide angle X-ray scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Gurun, Bilge; Bucknall, David G.; Thio, Yonathan S.; Teoh, Chin Ching; Harkin-Jones, Eileen (GIT); (Queens)

    2013-01-10

    A unique in situ multiaxial deformation device has been designed and built specifically for simultaneous synchrotron small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) measurements. SAXS and WAXS patterns of high-density polyethylene (HDPE) and HDPE/clay nanocomposites were measured in real time during in situ multiaxial deformation at room temperature and at 55 C. It was observed that the morphological evolution of polyethylene is affected by the existence of clay platelets as well as the deformation temperature and strain rate. Martensitic transformation of orthorhombic into monoclinic crystal phases was observed under strain in HDPE, which is delayed and hindered in the presence of clay nanoplatelets. From the SAXS measurements, it was observed that the thickness of the interlamellar amorphous region increased with increasing strain, which is due to elongation of the amorphous chains. The increase in amorphous layer thickness is slightly higher for the nanocomposites compared to the neat polymer.

  19. MUSIC - Multifunctional stereo imaging camera system for wide angle and high resolution stereo and color observations on the Mars-94 mission

    Science.gov (United States)

    Oertel, D.; Jahn, H.; Sandau, R.; Walter, I.; Driescher, H.

    1990-10-01

    Objectives of the multifunctional stereo imaging camera (MUSIC) system to be deployed on the Soviet Mars-94 mission are outlined. A high-resolution stereo camera (HRSC) and wide-angle opto-electronic stereo scanner (WAOSS) are combined in terms of hardware, software, technology aspects, and solutions. Both HRSC and WAOSS are push-button instruments containing a single optical system and focal plates with several parallel CCD line sensors. Emphasis is placed on the MUSIC system's stereo capability, its design, mass memory, and data compression. A 1-Gbit memory is divided into two parts: 80 percent for HRSC and 20 percent for WAOSS, while the selected on-line compression strategy is based on macropixel coding and real-time transform coding.

  20. Bio-Inspired Wide-Angle Broad-Spectrum Cylindrical Lens Based on Reflections from Micro-Mirror Array on a Cylindrical Elastomeric Membrane

    Directory of Open Access Journals (Sweden)

    Chi-Chieh Huang

    2014-06-01

    Full Text Available We present a wide-angle, broad-spectrum cylindrical lens based on reflections from an array of three-dimensional, high-aspect-ratio micro-mirrors fabricated on a cylindrical elastomeric substrate, functionally inspired by natural reflecting superposition compound eyes. Our device can perform one-dimensional focusing and beam-shaping comparable to conventional refraction-based cylindrical lenses, while avoiding chromatic aberration. The focal length of our cylindrical lens is 1.035 mm, suitable for micro-optical systems. Moreover, it demonstrates a wide field of view of 152° without distortion, as well as modest spherical aberrations. Our work could be applied to diverse applications including laser diode collimation, barcode scanning, holography, digital projection display, microlens arrays, and optical microscopy.

  1. Exploring Pore Formation of Atomic Layer-Deposited Overlayers by in Situ Small- and Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Karwal, Saurabh; Aoun, Bachir; Zhao, Haiyan; Ren, Yang; Canlas, Christian P.; Elam, Jeffrey W.; Winans, Randall E.

    2016-10-11

    In this work, we explore the pore structure of overcoated materials by in situ synchrotron small- and wide-angle X-ray scattering (SAXS)/(WAXS). Thin films of aluminum oxide (Al2O3) and titanium dioxide (TiO2) with thicknesses of 4.9 and 2.5 nm, respectively, are prepared by atomic layer deposition (ALD) on non-porous nanoparticles. In situ X-ray measurements reveal that porosity is induced in the ALD films by annealing the samples at high temperature. Moreover, this pore formation can be attributed to densification resulting from an amorphous to crystalline phase transition of the ALD films as confirmed by high resolution X-ray diffraction (XRD) and pair distribution function (PDF). Simultaneous SAXS/WAXS results not only show the porosity is formed by the phase transition but also that the pore size increases with temperature.

  2. Revealing the deep structure and rupture plane of the 2010 Maule, Chile earthquake (Mw = 8.8) using wide angle seismic data

    Science.gov (United States)

    Moscoso, Eduardo; Grevemeyer, Ingo; Contreras-Reyes, Eduardo; Flueh, Ernst R.; Dzierma, Yvonne; Rabbel, Wolfgang; Thorwart, Martin

    2011-07-01

    The 27 February, 2010 Maule earthquake (Mw = 8.8) ruptured ~ 400 km of the Nazca-South America plate boundary and caused hundreds of fatalities and billions of dollars in material losses. Here we present constraints on the fore-arc structure and subduction zone of the rupture area derived from seismic refraction and wide-angle data. The results show a wedge shaped body ~ 40 km wide with typical sedimentary velocities interpreted as a frontal accretionary prism (FAP). Landward of the imaged FAP, the velocity model shows an abrupt velocity-contrast, suggesting a lithological change which is interpreted as the contact between the FAP and the paleo accretionary prism (backstop). The backstop location is coincident with the seaward limit of the aftershocks, defining the updip limit of the co-seismic rupture and seismogenic zone. Furthermore, the seaward limit of the aftershocks coincides with the location of the shelf break in the entire earthquake rupture area (33°S-38.5°S), which is interpreted as the location of the backstop along the margin. Published seismic profiles at the northern and southern limit of the rupture area also show the presence of a strong horizontal velocity gradient seismic backstop at a distance of ~ 30 km from the deformation front. The seismic wide-angle reflections from the top of the subducting oceanic crust constrain the location of the plate boundary offshore, dipping at ~ 10°. The projection of the epicenter of the Maule earthquake onto our derived interplate boundary yielded a hypocenter around 20 km depth, this implies that this earthquake nucleated somewhere in the middle of the seismogenic zone, neither at its updip nor at its downdip limit.

  3. Seismological structures of the subducted Philippine Sea plate and the overriding SW Japan arc, - Reinterpretation of the wide-angle reflection data in the Kii Peninsula, SW Japan -

    Science.gov (United States)

    Iwasaki, Takaya; Kurashimo, Eiji; Abe, Susumu; Yokota, Ken; Iidaka, Takashi; Katao, Hiroshi; Higashinaka, Motonori; Nakanishi, Ayako; Kaneda, Yoshiyuki

    2017-04-01

    Our recent reinterpretation for seismic refraction/wide-angle reflection data in eastern Kii Peninsula, SW Japan, provided new structural information on the uppermost part of the subducted Philippine Sea (PHS) plate and overriding the SW Japan arc, including the landward reflectivity variation in the vicinity of the plate boundary and the large scale structural change within the SW Japan arc. The Kii peninsula is located in the eastern part of the well-known subduction zone along the Nankai trough where offshore M8-class megathrust earthquakes repeatedly occur. The plate boundary beneath this Peninsula is in the stable or conditionally stable regime except for its southernmost tip, which corresponds to the northwestern end of the rupture area at the last event (1944 Tonankai earthquake (M7.9)). The surface geology of the overriding SW Japan arc is divided to two parts by the E-W trending Median Tectonic Line (MTL), the most prominent tectonic boundary in SW Japan. South of the MTL, Cretaceous-Jurassic accretionary complexes are exposed, whose northernmost unit consists of high P-T metamorphic rocks (the Sanbagawa metamorphic belt (SMB)). The region north of the MTL is occupied by older accretionary complexes, partly suffered from the Cretaceous magmatic intrusions. Our seismic data from five dynamite shots were acquired in 2006 along 80-km line almost perpendicular to the Nankai trough. The structure of the SW Japan arc was obtained both from intensive wide-angle reflection analysis and advanced reflection processing by seismic interferometry technique. The former analysis delineated clear structural change in the uppermost crust across the MTL. In the latter processing, we retrieved virtual shot records at 512 receiver points from free-surface backscattered waves by the deconvolution interferometry. The subsequent CRS (Common Reflection Surface)/MDRS (Multi-Dip Reflection Surfaces) methods provided an enhanced image within the island arc, including a northward

  4. Neutrino telescopes

    CERN Document Server

    Carr, J

    2002-01-01

    This review presents the scientific objectives and status of Neutrino Telescope Projects. The science program of these projects covers: neutrino astronomy, dark matter searches and measurements of neutrino oscillations. The two neutrino telescopes in operation: AMANDA and BAIKAL will be described together with the ANTARES neutrino telescope being built in the Mediterranean. (18 refs).

  5. The calibration of wide-angle lens cameras using perspective and non-perspective projections in the context of real-time tracking applications

    Science.gov (United States)

    Willneff, Jochen; Wenisch, Oliver

    2011-07-01

    In most close-range photogrammetry applications, the cameras are modelled as imaging systems with perspective projection combined with the lens distortion correction as proposed by Brown in 1971. In the 1980s, the calibration of video cameras received considerable attention. This required compensation for further systematic effects caused by the digitization of the analogue image signal. Modelling the image process in that manner has become the widely-applied standard since then. To take advantage of the increased field of view of individual cameras, the use of wide angle as well as fisheye lenses became common in computer vision and close-range photogrammetry, again requiring appropriate modelling of the imaging process to ensure high accuracies. A.R.T. provides real-time tracking systems with infra-red cameras, which are in some cases equipped with short focal length lenses for the purpose of increased fields of view, resulting in larger trackable object volumes. Unfortunately the lens distortion of these cameras reaches magnitudes which can not be sufficiently modelled with the customary Brown model as - mainly at high excentricities such as image corners - the calculation of the correction is not applicable. Considerations to avoid modelling these lenses as fisheye projections led to an alternate and rather pragmatic approach, where the distortion model is extended by a fourth radial distortion coefficient. Due to numeric instabilities, a stepwise camera calibration is required to achieve convergence in the bundle adjustment process. This paper presents the modified lens distortion model, describes the stepwise calibration procedure and compares results in respect to the conventional approach. The results are also compared to the approach wherein the camera lens is modelled as a fisheye projection. The introduction of a fourth radial lens distortion parameter allows the correction of lens distortion effects over the full sensor area of wide angle lenses, which

  6. Dobre: Coincident Deep Near-vertical and Wide-angle Seismic Reflection and Refraction Profiling Across The Donbas Foldbelt In South-eastern Ukraine

    Science.gov (United States)

    Stephenson, R. A.; Thybo, H.; Stovba, S. M.; Starostenko, V. I.; Dobre Working Groups

    DOBRE is a multidisciplinary project aimed at studying processes governing intracra- tonic rifting and inversion (uplift and shortening) targeted on the Donbas Foldbelt (DF), the strongly inverted and compressionally deformed segment of a Late Devonian intracratonic rift basin north of the Ukrainian Shield (UkS). DOBREflection (250-km deep seismic reflection data acquired in 2000 and 2001) provides detailed resolution of both basin infill and deep crustal structures and DOBREfraction (a coincident 350- km wide-angle profile acquired in 1999) provides a complementary velocity model of the sedimentary basin, crust, and upper mantle of the DF area. The integrated DOBRE results indicate that the thickness of sediments reaches some 20-km in the axial part of the DF. There is a good correlation of the basement reflection horizon with the base of the supracrustal sedimentary layer in the velocity model. Pronounced reflections from a thrust affecting the whole sedimentary succession as well as the upper crust beneath the southern margin of the has been smoothed out in the velocity model although wide-angle and refracted seismic phases indicate severe structural complexity. The Moho displays some topography but lies on average at about a depth of 40-km along the DOBREfraction profile. This generally corresponds to a broad (1 s) reflective band that can be traced along the whole reflection profile at about 14 s below the UkS and at 12 s below the DF. The crystalline crust thins significantly beneath the basin and this is attributed to rifting processes that affected the EEC in the Devonian. Reflectiv- ity is seen in the entire crust, with a number of strong reflectors appearing within the UkS and continuing into the basin area. Isovelocity contours in the refraction model are parallel to sub-parallel to the reflectivity fabric in this area. Further north, a high velocity lower crustal layer is characterised by enhanced normal-incidence reflectiv- ity. The reflectivity

  7. Early-stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide-angle and multichannel seismic study

    Science.gov (United States)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; Franco, R.

    2013-08-01

    Extension of the continental lithosphere leads to the formation of rift basins and ultimately may create passive continental margins. The mechanisms that operate during the early stage of crustal extension are still intensely debated. We present the results from coincident multichannel seismic and wide-angle seismic profiles that transect across the northern Tyrrhenian Sea Basin. The profiles cross the Corsica Basin (France) to the Latium Margin (Italy) where the early-rift stage of the basin is well preserved. We found two domains, each with a distinct tectonic style, heat flow and crustal thickness. One domain is the Corsica Basin in the west that formed before the main rift phase of the northern Tyrrhenian Sea opening (˜8-4 Ma). The second domain is rifted continental crust characterized by tilted blocks and half-graben structures in the central region and at the Latium Margin. These two domains are separated by a deep (˜10 km) sedimentary complex of the eastern portion of the Corsica Basin. Travel-time tomography of wide-angle seismic data reveals the crustal architecture and a subhorizontal 15-17 ± 1 km deep Moho discontinuity under the basin. To estimate the amount of horizontal extension we have identified the pre-, syn-, and post-tectonic sedimentary units and calculated the relative displacement of faults. We found that major faults initiated at angles of 45°-50° and that the rifted domain is horizontally stretched by a factor of β ˜ 1.3 (˜8-10 mm/a). The crust has been thinned from ˜24 to ˜17 km indicating a similar amount of extension (˜30%). The transect represents one of the best imaged early rifts and implies that the formation of crustal-scale detachments, or long-lived low-angle normal faults, is not a general feature that controls the rift initiation of continental crust. Other young rift basins, like the Gulf of Corinth, the Suez Rift or Lake Baikal, display features resembling the northern Tyrrhenian Basin, suggesting that half

  8. The limits of narrow and wide-angle AVA inversions for high Vp/Vs ratios: An application to elastic seabed characterization

    Science.gov (United States)

    Aleardi, Mattia; Tognarelli, Andrea

    2016-08-01

    Since its introduction in the oil and gas industry, amplitude versus angle (AVA) inversion has become a standard tool in deep hydrocarbon exploration. However, with the intensification of offshore construction activity, applications of this method have been extended to evaluate the elastic properties of seabed sediments and of the shallowest part of the subsurface. These regions are often characterized by undercompacted sediments with very low S-wave velocities (Vs) and high P-wave velocity to S-wave velocity (Vp/Vs) ratios. However, the importance of the Vp/Vs ratio is usually underrated in AVA inversion. In this study, we analyse the limits of the AVA method in cases of high Vp/Vs ratios and the benefits introduced by wide-angle reflections in constraining the inversion results. A simplified seabed model that is characterized by a high Vp/Vs ratio is used to study the influence of the elastic and viscoelastic parameters on the P-wave reflection coefficients and to compute the error function of the AVA inversion. In addition, a synthetic AVA inversion is performed on this simplified model, which enables us to apply the sensitivity analysis tools to the inversion kernel. These theoretical analyses show that in the case of high Vp/Vs ratios, the Vs contrast at the reflecting interface plays a very minor role in determining the P-wave reflection coefficients and that the viscoelastic effects can be neglected when only pre-critical angles are considered in the inversion. In addition, wide-angle reflections are essential to reducing both the cross-talk between the inverted elastic parameters and the uncertainties in the Vp and density estimations, but they are not sufficient to better constrain the Vs estimation. As an application to field data, we derive the elastic properties of the seabed interface by applying AVA inversion to a 2D seismic dataset from a well-site survey acquisition. The limited water depth, the maximum available source-to-receiver offset, and the

  9. Space Telescopes

    Science.gov (United States)

    2010-01-01

    Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 166 9. Space telescopes Figure 9.1: Paraboloid telescope. In the following sections, NI...planets nearby a brighter star. Normal-incidence telescopes One-mirror telescope The one-mirror telescope (mostly an off-axis paraboloid ; Figure 9.1) has...rotation of the whole instrument (see SUMER/SOHO, Wilhelm et al (1995) and EIS/Hinode, Culhane et al (2007)). The paraboloid field curvature (Petzval

  10. Three-Dimensional Morphology Control Yielding Enhanced Hole Mobility in Air-Processed Organic Photovoltaics: Demonstration with Grazing-Incidence Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Levi M. J. [School of Polymers; Bhattacharya, Mithun [School of Polymers; Wu, Qi [School of Polymers; Youm, Sang Gil [Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States; Nesterov, Evgueni E. [Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States; Morgan, Sarah E. [School of Polymers

    2017-06-28

    Polymer organic photovoltaic (OPV) device performance is defined by the three-dimensional morphology of the phase-separated domains in the active layer. Here, we determine the evolution of morphology through different stages of tailored solvent vapor and thermal annealing techniques in air-processed poly(3-hexylthiophene-2,5-diyl)/phenyl-C61-butyric acid methyl ester-based OPV blends. A comparative evaluation of the effect of solvent type used for vapor annealing was performed using grazing-incidence wide-angle X-ray scattering, atomic force microscopy, and UV–vis spectroscopy to probe the active-layer morphology. A nonhalogenated orthogonal solvent was found to impart controlled morphological features within the exciton diffusion length scales, enhanced absorbance, greater crystallinity, increased paracrystalline disorder, and improved charge-carrier mobility. Low-boiling, fast-diffusing isopropanol allowed the greatest control over the nanoscale structure of the solvents evaluated and yielded a cocontinuous morphology with narrowed domains and enhanced paths for the charge carrier to reach the anode.

  11. Identification and quantification of the crystalline structures of poly(vinylidene fluoride) sutures by wide-angle X-ray scattering and differential scanning calorimetry.

    Science.gov (United States)

    Laroche, G; Lafrance, C P; Prud'homme, R E; Guidoin, R

    1998-02-01

    The outstanding biocompatibility of the polyvinylidene fluoride (PVDF) monofilament suture together with other desirable characteristics, such as ease of handling and resistance to biodegradation, makes it an attractive alternative monofilament suture material for cardiovascular surgery. However, to achieve a high performance suture, the polymeric raw material must be exposed to different treatments, which lead to different degrees and types of crystallization. Since these crystalline modifications deeply influence the mechanical characteristics and the biostability of the sutures, the authors hereby propose a method of quantifying the different structures of PVDF using wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The commercial devices are achieved by coloring and processing the polymeric raw material. The white and unprocessed 4-0 unswaged suture presents 19% of the alpha phase, 38% of the beta structure, and no gamma form. Coloration increases the amount of the beta phase by 5-9% at the expense of the alpha phase. On the other hand, processing the fibers lead to the conversion of some of the amorphous phase to the gamma structure, the importance of which is 6-7%. Finally, tensile measurements performed on the different PVDF fibers clearly proves that their mechanical characteristics depend on the presence of these crystalline forms in the polymeric structure of PVDF.

  12. Assessing the impact of polymers on the pH-induced precipitation behavior of poorly water soluble compounds using synchrotron wide angle X-ray scattering.

    Science.gov (United States)

    Hsieh, Yi-Ling; Box, Karl; Taylor, Lynne S

    2014-09-01

    The aim of this study was to investigate the pH-induced precipitation behavior of four ionizable compounds (papaverine, dipyridamole, glyburide, and warfarin) in the absence and presence of polymers. Polymers selected included nonionic, anionic, and cationic polymers. Precipitates were analyzed immediately after formation using high-energy radiation wide-angle X-ray scattering analysis and polarized light microscopy. Papaverine immediately crystallized to the original solid-state form upon creation of a highly supersaturated solution and polymers were unable to prevent crystallization. Dipyridamole also crystallized rapidly, forming a metastable polymorph that was stabilized by several of the cellulosic polymers. For glyburide and warfarin, although the compounds readily crystallized in the absence of the polymers, several of the polymers were able to prevent crystallization for more than 6 h. In general, measurements of solution concentration immediately following precipitation corroborated the solid-state analysis results, with the solution phase for the noncrystalline precipitates having a concentration considerably higher than that of the equilibrium solubility value, whereas for the crystalline precipitates, values were closer to the equilibrium solubility. Thus, precipitation to a noncrystalline solid was found to be promoted by the presence of some polymers, resulting in the formation of a supersaturated solution.

  13. Influences of wide-angle and multi-beam interference on the chromaticity and efficiency of top-emitting white organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Lingling; Zhou, Hongwei; Chen, Shufen, E-mail: iamsfchen@njupt.edu.cn; Liu, Bin; Wang, Lianhui [Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Shi, Hongying [Jiangsu-Singapore Joint Research Center for Organic/Bio- Electronics and Information Displays and Institute of Advanced Materials, Nanjing Tech University, Nanjing 211816 (China); Huang, Wei, E-mail: iamdirector@njupt.edu.cn [Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Jiangsu-Singapore Joint Research Center for Organic/Bio- Electronics and Information Displays and Institute of Advanced Materials, Nanjing Tech University, Nanjing 211816 (China)

    2015-02-28

    Wide-angle interference (WI) and multi-beam interference (MI) in microcavity are analyzed separately to improve chromaticity and efficiency of the top-emitting white organic light-emitting diodes (TWOLEDs). A classic electromagnetic theory is used to calculate the resonance intensities of WI and MI in top-emitting organic light-emitting diodes (TOLEDs) with influence factors (e.g., electrodes and exciton locations) being considered. The role of WI on the performances of TOLEDs is revealed through using δ-doping technology and comparing blue and red EML positions in top-emitting and bottom-emitting devices. The blue light intensity significantly increases and the chromaticity of TWOLEDs is further improved with the use of enhanced WI (the blue emitting layer moving towards the reflective electrode) in the case of a weak MI. In addition, the effect of the thicknesses of light output layer and carrier transport layers on WI and MI are also investigated. Apart from the microcavity effect, other factors, e.g., carrier balance and carrier recombination regions are considered to obtain TWOLEDs with high efficiency and improved chromaticity near white light equal-energy point.

  14. Small-angle and wide-angle X-ray scattering study on the bilayer structure of synthetic and bovine heart cardiolipins

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroshi [Biophysics Laboratory, Department of Chemistry and Chemical Biology, Gunma University, Maebashi, Gunma, 371-8510 (Japan); Hayakawa, Tomohiro [Life Science Laboratory, Advanced Materials Laboratories, Sony Corporation, Yushima, Bunkyo-ku, Tokyo, 113-8510 (Japan); Ito, Kazuki; Takata, Masaki [Structural Materials Science Laboratory, RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan); Kobayashi, Toshihide, E-mail: htakahas@chem-bio.gunma-u.ac.j [Lipid Biology Laboratory, RIKEN, Wako, Saitama 351-0198 (Japan)

    2010-10-01

    Cardiolipin (CL) is a membrane phospholipid containing four fatty acid chains. CL plays an important role in energy transformation in mitochondria. The disorder of CL biosynthesis is involved in a genetic disease, Barth syndrome. Alteration of fatty acid composition of CLs has been found in Barth syndrome patients, i.e., the decrease of unsaturated fatty acid chains. In this study, we investigated how the degree of saturation alters the structure of CL bilayers by using X-ray scattering. Bovine heart CL and two synthetic CLs were compared. Fatty acid compositions of these three CLs have different saturation. Small-angle X-ray scattering data showed that the decrease of the number of double bonds in the unsaturated fatty acid chains causes to thicken the CL bilayers. In addition, wide-angle X-ray scattering data suggested that the decrease reduces the degree of disorder of the hydrophobic region in a liquid crystalline phase. These results may be related to the dysfunction of mitochondria in Barth syndrome.

  15. A spider-like outflow in Barnard 5 - IRS 1: The transition from a collimated jet to a wide-angle outflow?

    CERN Document Server

    Zapata, Luis A; Brassfield, Erin; Palau, Aina; Patel, Nimesh; Pineda, Jaime E

    2014-01-01

    We present line and continuum observations made with the Submillimeter Array (SMA) of the young stellar object Barnard 5 - IRS1 located in the Perseus molecular cloud. Our $^{12}$CO(2-1) line observations resolve the high-velocity bipolar northeast-southwest outflow associated with this source. We find that the outflowing gas shows different structures at three different velocity regimes, in both lobes, resulting in a spider-like morphology. In addition to the low-velocity, cone-like (wide-angle) lobes that have previously been observed, we report the presence of intermediate-velocity parabolic shells emerging very close to the Class I protostar, as well as high velocity molecular bullets that appear to be associated to the optical/IR jet emanating from this source. These compact high-velocity features reach radial velocities of about 50 km s$^{-1}$ away from the cloud velocity. We interpret the peculiar spider-like morphology is a result of the molecular material being entrained by a wind with both a collima...

  16. A mobile system for a comprehensive online-characterization of nanoparticle aggregates based on wide-angle light scattering and laser-induced incandescence

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Franz J. T.; Will, Stefan, E-mail: stefan.will@fau.de [Lehrstuhl für Technische Thermodynamik (LTT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91058 (Germany); Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91052 (Germany); Cluster of Excellence Engineering of Advanced Materials (EAM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91052 (Germany); Altenhoff, Michael [Lehrstuhl für Technische Thermodynamik (LTT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91058 (Germany); Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen 91052 (Germany)

    2016-05-15

    A mobile demonstrator for the comprehensive online-characterization of gas-borne nanoparticle aggregates is presented. Two optical measurement techniques are combined, both utilizing a pulsed Nd:YAG laser as light source. Aggregate size and fractal dimension are measured by Wide-Angle Light Scattering (WALS). An ellipsoidal mirror images elastically scattered light from scattering angles between 10° and 165° onto a CCD-camera chip resulting in an almost complete scattering diagram with high angular resolution. Primary particle size and volume fraction are measured by time-resolved Laser-Induced Incandescence (TiRe-LII). Here, particles are heated up to about 3000 K by the short laser pulse, the enhanced thermal radiation signal is detected with gated photomultiplier tubes. Analysis of the signal decay time and maximum LII-signal allows for the determination of primary particle diameter and volume fraction. The performance of the system is demonstrated by combined measurements on soot nanoparticle aggregates from a soot aerosol generator. Particle and aggregate sizes are varied by using different equivalence ratios of the combustion in the generator. Soot volume fraction can be adjusted by different levels of dilution with air. Online-measurements were carried out demonstrating the favorable performance of the system and the potential for industrial applications such as process control and product development. The particle properties obtained are confirmed through transmission electron microscopy analysis on representative samples.

  17. Seismic reflection data imaging and interpretation from Braniewo2014 experiment using additional wide-angle refraction and reflection and well-logs data

    Science.gov (United States)

    Trzeciak, Maciej; Majdański, Mariusz; Białas, Sebastian; Gaczyński, Edward; Maksym, Andrzej

    2015-04-01

    Braniewo2014 reflection and refraction experiment was realized in cooperation between Polish Oil and Gas Company (PGNiG) and the Institute of Geophysics (IGF), Polish Academy of Sciences, near the locality of Braniewo in northern Poland. PGNiG realized a 20-km-long reflection profile, using vibroseis and dynamite shooting; the aim of the reflection survey was to characterise Silurian shale gas reservoir. IGF deployed 59 seismic stations along this profile and registered additional full-spread wide-angle refraction and reflection data, with offsets up to 12 km; maximum offsets from the seismic reflection survey was 3 km. To improve the velocity information two velocity logs from near deep boreholes were used. The main goal of the joint reflection-refraction interpretation was to find relations between velocity field from reflection velocity analysis and refraction tomography, and to build a velocity model which would be consistent for both, reflection and refraction, datasets. In this paper we present imaging results and velocity models from Braniewo2014 experiment and the methodology we used.

  18. Continental hyperextension, mantle exhumation, and thin oceanic crust at the continent-ocean transition, West Iberia: New insights from wide-angle seismic

    Science.gov (United States)

    Davy, R. G.; Minshull, T. A.; Bayrakci, G.; Bull, J. M.; Klaeschen, D.; Papenberg, C.; Reston, T. J.; Sawyer, D. S.; Zelt, C. A.

    2016-05-01

    Hyperextension of continental crust at the Deep Galicia rifted margin in the North Atlantic has been accommodated by the rotation of continental fault blocks, which are underlain by the S reflector, an interpreted detachment fault, along which exhumed and serpentinized mantle peridotite is observed. West of these features, the enigmatic Peridotite Ridge has been inferred to delimit the western extent of the continent-ocean transition. An outstanding question at this margin is where oceanic crust begins, with little existing data to constrain this boundary and a lack of clear seafloor spreading magnetic anomalies. Here we present results from a 160 km long wide-angle seismic profile (Western Extension 1). Travel time tomography models of the crustal compressional velocity structure reveal highly thinned and rotated crustal blocks separated from the underlying mantle by the S reflector. The S reflector correlates with the 6.0-7.0 km s-1 velocity contours, corresponding to peridotite serpentinization of 60-30%, respectively. West of the Peridotite Ridge, shallow and sparse Moho reflections indicate the earliest formation of an anomalously thin oceanic crustal layer, which increases in thickness from ~0.5 km at ~20 km west of the Peridotite Ridge to ~1.5 km, 35 km further west. P wave velocities increase smoothly and rapidly below top basement, to a depth of 2.8-3.5 km, with an average velocity gradient of 1.0 s-1. Below this, velocities slowly increase toward typical mantle velocities. Such a downward increase into mantle velocities is interpreted as decreasing serpentinization of mantle rock with depth.

  19. An analysis of the first-arrival times picked on the DSS and wide-angle seismic section recorded in Italy since 1968

    Directory of Open Access Journals (Sweden)

    R. Tondi

    2004-06-01

    Full Text Available We performed an analysis of refraction data recorded in Italy since 1968 in the frame of the numerous deep seismic sounding and wide-angle reflection/refraction projects. The aims of this study are to construct a parametric database including the recording geometric information relative to each profile, the phase pickings and the results of some kinematic analyses performed on the data, and to define a reference 1D velocity model for the Italian territory from all the available refraction data. As concerns the first goal, for each seismic section we picked the P-wave first-arrival-times, evaluated the uncertainties of the arrival-times pickings and determined from each travel time-offset curve the 1D velocity model. The study was performed on 419 seismic sections. Picking was carried out manually by an algorithm which includes the computation of three picking functions and the picking- error estimation. For each of the travel time-offset curves a 1D velocity model has been calculated. Actually, the 1D velocity-depth functions were estimated in three different ways which assume: a constant velocitygradient model, a varying velocity-gradient model and a layered model. As regards the second objective of this work, a mean 1D velocity model for the Italian crust was defined and compared with those used for earthquake hypocentre locations and seismic tomographic studies by different institutions operating in the Italian area, to assess the significance of the model obtained. This model can be used in future works as input for a next joint tomographic inversion of active and passive seismic data.

  20. The GLIMPCE seismic experiment: Onshore refraction and wide-angle reflection observations from a fan line over the Lake Superior Midcontinent Rift System

    Science.gov (United States)

    Epili, Duryodhan; Mereu, Robert F.

    The 1986 GLIMPCE experiment (Great Lakes International Multidisciplinary Program for Crustal Evolution) was a combined on-ship seismic reflection and onshore seismic refraction experiment designed to determine the structure of the crust beneath the Great Lakes. The main tectonic targets of interest were the Midcontinent Rift System, the Grenville Front, the Penokean and Huronian Fold Belts and the Michipicoten Greenstone Belt. The source of the seismic energy came from a large air gun array fired at closely spaced intervals (50-350 m) over several long lines (150-350 km) crossing the lakes. Major participants of this experiment were the Geological Survey of Canada, the United States Geological Survey and a number of universities and research institutes on both sides of the border. The University of Western Ontario (UWO) collected data at five separate land stations using portable seismic refraction instruments. In this paper we present the results of a fan profile which was recorded from a UWO station on Michipicoten Island for the N-S line A which crossed the axis of the Lake Superior Synclinal Basin. The azimuth and distance ranges for this profile were 237 to 321 degrees and 120 to 170 km respectively. Detailed observations of the record sections show that p. is not a simple arrival but forms a rather complex pattern of irregular multiple arrivals. The wide-angle PmP reflection signals from the Moho are strong and well obilerved only for the shots fired near the ends of the line. The signals from the middle of the profile arrive relatively late and form very weak complex wave trains. These results indicate that the Moho in that area is probably greatly disrupted and gives added support to the rift theory for the structure under the lake. The observations also support the results of earlier crustal studies of Lake Superior which showed that the crust under the eastern part of the lake was exceedingly thick.

  1. The crustal structure of continental shelf in northern South China Sea: revealed by joint onshore-offshore wide-angle seismic survey

    Science.gov (United States)

    Cao, Jinghe; Sun, Jinlong; Xia, Shaohong; Wan, Kuiyuan; Xu, Huilong

    2017-04-01

    Known as a significant region for studying tectonic relationship between South China block and South China Sea (SCS) block and evolution of rifted basin in continental margin, the continental shelf of northern SCS not only preserved the information about intensive tectonic deformation and magmatism generated by the west Pacific subducted to Eurasian Plate in late Mesozoic, but also recorded the process from continental margin rifting to seafloor spreading of SCS in Cenozoic for the same mechanical property. To investigate crustal structure of continental shelf in northern SCS, a wide-angle onshore-offshore seismic experiment and a coincident multi-channel seismic (MCS) profile were carried out across the onshore-offshore transitional zone in northern SCS, 2010. A total of 14 stations consisted of ocean bottom seismometers, portable and permanent land stations were deployed during the survey. The two-dimensional precise crustal structure model of central continental shelf in northern SCS was constructed from onshore to offshore. The model reveals that South China block is a typical continental crust with a 30-32 km Moho depth, and a localized high-velocity anomaly in middle-lower crust under land area near Hong Kong was imaged, which may reflect magma underplating caused by subduction of paleo-Pacific plate in late Mesozoic. The Littoral Fault Zone (LFZ) lies 12 km south of Dangan Island with a width of 18-20 km low-velocity fracture zone from surface to Moho discontinuity. The shelf zone south of LFZ was consisted of a differential thinning upper and lower continental crust, which indicate stretch thinning of passive continent margin during the Cenozoic spreading of the SCS. All these results appear to further confirm that the northern margin of SCS experienced a transition from active margin to passive one during late Mesozoic and Cenozoic.

  2. Two Wide-Angle Imaging Neutral-Atom Spectrometers and Interstellar Boundary Explorer energetic neutral atom imaging of the 5 April 2010 substorm

    Science.gov (United States)

    McComas, D. J.; Buzulukova, N.; Connors, M. G.; Dayeh, M. A.; Goldstein, J.; Funsten, H. O.; Fuselier, S.; Schwadron, N. A.; Valek, P.

    2012-03-01

    This study is the first to combine energetic neutral atom (ENA) observations from Two Wide-Angle Imaging Neutral-Atom Spectrometers (TWINS) and Interstellar Boundary Explorer (IBEX). Here we examine the arrival of an interplanetary shock and the subsequent geomagnetically effective substorm on 5 April 2010, which was associated with the Galaxy 15 communications satellite anomaly. IBEX shows sharply enhanced ENA emissions immediately upon compression of the dayside magnetosphere at 08:26:17+/-9 s UT. The compression drove a markedly different spectral shape for the dayside emissions, with a strong enhancement at energies >1 keV, which persisted for hours after the shock arrival, consistent with the higher solar wind speed, density, and dynamic pressure (˜10 nPa) after the shock. TWINS ENA observations indicate a slower response of the ring current and precipitation of ring current ions as low-altitude emissions ˜15 min later, with the >50 keV ion precipitation leading the internal magnetospheric processes are occurring after compression of the magnetosphere and before the ring current ions end up in the loss cone and precipitate into the ionosphere. We also compare MHD simulation results with both the TWINS and IBEX ENA observations; while the overall fluxes and distributions of emissions were generally similar, there were significant quantitative differences. Such differences emphasize the complexity of the magnetospheric system and importance of the global perspective for macroscopic magnetospheric studies. Finally, Appendix A documents important details of the TWINS data processing, including improved binning procedures, smoothing of images to a given level of statistical accuracy, and differential background subtraction.

  3. Three-dimensional crustal velocity structure of P-wave in East China from wide-angle reflection and refraction surveys

    Institute of Scientific and Technical Information of China (English)

    ZHAO ZhiXin; XU JiRen

    2009-01-01

    The 3-D crustal structure of P-wave velocity in East China is studied based on the data obtained by wide-angle seismic reflection and refraction surveys.The results suggest that a deep Moho disconti-nuity exists in the western zone of the study region,being 35-48 thick.High-velocity structure zones exist in the upper crust shallower than 20 km beneath the Sulu and Dabie regions.The cause of high-velocity zones is attributable to high-pressure metamorphic (HPM) and ultra-high-pressure metamorphic (UHPM) terranes with high velocity and density exhuming up to the upper crust in the Sulu and Dabie orogenies.Anomalous zones of low velocity are in the lower crust,about 30 km beneath the Sulu and Dabie regions.The Moho discontinuity is as deep as 38 km beneath the Dabie region,deeper than those in the surrounding areas.The Moho discontinuity beneath the Sulu orogenic region is also a little deeper than those in its vicinity,being about 32 km.The deep Moho discontinuity zone implies that the low crustal velocity structure zone is in that region.The low-velocity characteristics in the lower crust are probably related to the remnant crustal root of the old mountains due to the orogeny in the Sulu and Dabie regions.The high-velocity anomalous zones in the upper crust and low-velocity anomalous zones in the lower crust beneath the Sulu region are all located northeast of the northern segment of the Tan-Lu fault.However,the high- and low-velocity anomalous zones beneath the Dabie region are located southwest of the southern segment of the Tan-Lu fault.Such a distribution of the velocity-anomalous zones looks to be attributable a left lateral slip motion along the Tan-Lu fault.The distribution pattern of the velocity-anomalous zones may show some evidence for the left strike-slip motion regime of the Tan-Lu fault.

  4. 3D P-wave velocity structure of the deep Galicia rifted margin: A first analysis of the Galicia 3D wide-angle seismic dataset

    Science.gov (United States)

    Bayrakci, Gaye; Minshull, Timothy A.; Davy, Richard G.; Karplus, Marianne S.; Kaeschen, Dirk; Papenberg, Cord; Krabbenhoeft, Anne; Sawyer, Dale; Reston, Timothy J.; Shillington, Donna J.; Ranero, César R.

    2014-05-01

    Galicia 3D, a reflection-refraction and long offset seismic experiment was carried out from May through September 2013, at the Galicia rifted margin (in the northeast Atlantic Ocean, west of Spain) as a collaboration between US, UK, German and Spanish groups. The 3D multichannel seismic acquisition conducted by R/V Marcus Langseth covered a 64 km by 20 km (1280 km2) zone where the main geological features are the Peridotite Ridge (PR), composed of serpentinized peridotite and thought be upper mantle exhumed to the seafloor during rifting, and the S reflector which has been interpreted to be a low angle detachment fault overlain by fault bounded, rotated, continental crustal blocks. In the 3D box, two airgun arrays of 3300 cu.in. were fired alternately (in flip-flop configuration) every 37.5 m. All shots are recorded by 44 short period four component ocean bottom seismometers (OBS) and 26 ocean bottom hydrophones (OBH) deployed and recovered by R/V Poseidon, as well as four 6 km hydrophone streamers with 12.5 m channel spacing towed by R/V Marcus Langseth. We present the preliminary results of the first arrival time tomography study which is carried out with a subset of the wide-angle dataset, in order to generate a 3D P-wave velocity volume for the entire depth sampled by the reflection data. After the relocation of OBSs and OBHs, an automatic first-arrival time picking approach is applied to a subset of the dataset, which comprises more than 5.5 million source-receiver pairs. Then, the first-arrival times are checked visually, in 3-dimensions. The a priori model used for the first-arrival time tomography is built up using information from previous seismic surveys carried out at the Galicia margin (e.g. ISE, 1997). The FAST algorithm of Zelt and Barton (1998) is used for the first-arrival time inversion. The 3D P-wave velocity volume can be used in interpreting the reflection dataset, as a starting point for migration, to quantify the thinning of the crustal layers

  5. SNAP telescope

    Energy Technology Data Exchange (ETDEWEB)

    Lampton, Michael L.; Akerlof, C.W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E.; Bebek, C.; Bergstrom, L.; Bercovitz, J.; Bernstein, G.; Bester, M.; Bonissent, A.; Bower, C.; Carithers Jr., W.C.; Commins, E.D.; Day, C.; Deustua, S.E.; DiGennaro, R.; Ealet, A.; Ellis,R.S.; Eriksson, M.; Fruchter, A.; Genat, J.-F.; Goldhaber, G.; Goobar,A.; Groom, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Holland,S.E.; Huterer, D.; Karcher, A.; Kim, A.G.; Kolbe, W.; Krieger, B.; Lafever, R.; Lamoureux, J.; Levi, M.E.; Levin, D.S.; Linder, E.V.; Loken,S.C.; Malina, R.; Massey, R.; McKay, T.; McKee, S.P.; Miquel, R.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi,H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Pratt, R.; Prieto,E.; Refregier, A.; Rhodes, J.; Robinson, K.; Roe, N.; Sholl, M.; Schubnell, M.; Smadja, G.; Smoot, G.; Spadafora, A.; Tarle, G.; Tomasch,A.; von der Lippe, H.; Vincent, R.; Walder, J.-P.; Wang, G.; Wang, G.

    2002-07-29

    The SuperNova/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages of annular-field three-mirror anastigmat (TMA) telescopes for applications such as SNAP, and describe the features of the specific optical configuration that we have baselined for the SNAP mission. We discuss the mechanical design and choice of materials for the telescope. Then we present detailed ray traces and diffraction calculations for our baseline optical design. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of tasks to be carried out during the upcoming SNAP research and development phase.

  6. Crustal nature and seismic structure of the geological provinces offshore the SW Iberia: Highlights of the NEAREST-SEIS wide-angle seismic survey

    Science.gov (United States)

    Martínez-Loriente, S.; Sallares, V.; Gailler, A.; Bartolome, R.; Gracia, E.; Gutscher, M.; Diaz, J.

    2011-12-01

    The SW Iberian margin hosts the present day NW-SE plate convergence between the European and African Plates at a rate of 4.5 mm/yr causing seismic activity of moderate magnitude. During fall 2008 and in the frame of the EU-funded NEAREST project, was carried out a wide-angle seismic survey (NEAREST-SEIS cruise) consisting in 2 profiles. The main objectives of the survey were to gather information about the geometry of the crust-mantle boundary, identify the nature of the different geological provinces, obtain the physical properties of the crust, and unveil the deep geometry of the interfaces between main faults. A total of 30 OBS were deployed along profile P1, which is 356 km long and trends NW-SE running from the Tagus Abyssal Plain (TAP), Gorringe Bank (GB), Horseshoe Abyssal Plain (HAP), Coral Patch Ridge (CPR), and finally reaching the thrust-and-fold belt of the Seine Abyssal Plain (SAP). The inverted model shows four well-differentiated domains in terms of seismic structure. In the TAP there is a 3-4 km-thick sediment layer with low velocity, lying above a basement showing a remarkably high velocity (< 7 km/s), similar to that of the basement outcropping in the GB. In the HAP the sedimentary cover is thicker, showing an uppermost unit with very low velocity corresponding to the Upper Miocene Horseshoe Gravitational Unit, on top of a higher velocity lower unit, which corresponds to the Mesozoic sedimentary sequence, with a total thickness of 5 km. The basement shows the same velocity distribution as in TAP and GB, suggesting a common nature and origin. According to its seismic structure, we interpret this basement as very serpentinized, exhumed upper mantle. In contrast, the CPR and SAP show evidence for the presence of a well-developed, 6-7 km-thick oceanic crust, underlying the 2-3 km thick Mesozoic and Neogene sedimentary sequence. Profile P2 is 256 km long and trends N-S, across the Iberian margin shelf, Portimao Bank, Gulf of Cadiz imbricated wedge and

  7. Seismic structure of the main geological provinces off the SW Iberian margin: first results from the NEAREST-SEIS wide-angle seismic survey

    Science.gov (United States)

    Sallarès, Valentí; Martínez-Loriente, Sara; Gailler, Audrey; Bartolomé, Rafael; Gutscher, Marc-André; Graindorge, David; Lia Grácia, Eulà; Díaz, Jordi

    2010-05-01

    The region offshore the SW Iberian margin hosts the present-day NW-SE plate convergence between the European and African Plates at a rate of 4.5 mm/yr, fact that causes continuous seismic activity of moderate magnitude. In autumn 2008 a Spanish-French team carried out a refraction and wide-angle reflection seismic survey in the area (NEAREST-SEIS cruise), in the framework of the EU, FP6-funded NEAREST project. During the survey two long seismic profiles were acquired using a pool of 36 Ocean Bottom Seismometers (OBS), with the objectives of providing information about the geometry of the crust-mantle boundary and the physical properties of the crust, revealing the deep geometry of the main fault interfaces, and identifying the nature of the basement and the limits of the different geological provinces in the region. A total of 30 OBS were deployed along profile P1, which is 356 km long and trends NW-SE from the Tagus abyssal plain (TAP), crossing the Gorringe bank (GB), the Horseshoe abyssal plain (HAP) and the Coral Patch Ridge (CPR), up to the thrust-and-fold belt of the Seine abyssal plain (SAP). The acquired data were modeled by joint refraction and reflection travel time inversion, following a layer-stripping strategy. The inverted model show four well-differentiated domains in terms of its seismic structure: In the TAP a 3-4 km-thick, low velocity sedimentary layer covers the basement, which shows a remarkably high velocity (>7 km/s), similar to that of the basement outcropping in the Gorringe bank. In the HAP the sedimentary cover is thicker, showing an upper unit with low velocity corresponding to the Horseshoe gravitational unit, on top of a higher velocity lower unit, which may represent the highly consolidated Mesozoic sedimentary sequence. The thickness of the two units together exceeds 5 km. The basement shows the same velocity distribution as in TAP and GB, suggesting a common nature and origin. According to its seismic structure, and considering that

  8. Seismic structure and crustal nature of the geological provinces off the SW Iberian margin: results of the NEAREST-SEIS wide-angle seismic survey

    Science.gov (United States)

    Sallares, V.; Martinez, S.; Gailler, A.; Gutscher, M.; Bartolome, R.; Gracia, E.; Diaz, J.

    2010-12-01

    The region offshore the SW Iberian margin hosts the present-day NW-SE plate convergence between the European and African Plates causing continuous seismic activity of moderate magnitude. In autumn 2008 a Spanish-French team carried out a wide-angle seismic survey in the area (NEAREST-SEIS cruise), in the framework of the EU-funded NEAREST project. During the survey two long profiles were acquired using a pool of 36 Ocean Bottom Seismometers (OBS), to provide information about the crustal structure and nature of the different geological provinces, and to reveal the deep geometry of the main fault interfaces. A total of 30 OBS were deployed along profile P1, which is 356 km long and trends NW-SE from the Tagus abyssal plain (TAP), crossing the Gorringe bank (GB), the Horseshoe abyssal plain (HAP) and the Coral Patch Ridge (CPR), up to the thrust-and-fold belt of the Seine abyssal plain (SAP). The inverted model along this profile show four different domains. In the TAP a 3-4 km-thick, low velocity sedimentary layer covers the basement, which shows a velocity >7 km/s just 2-3 km below its top, similarly to that of the basement outcropping in the Gorringe bank. In the HAP the sedimentary cover is thicker, showing an upper unit with low velocity corresponding to the Horseshoe gravitational unit, on top of a higher velocity lower unit, which may represent the highly consolidated Mesozoic sedimentary sequence, with a total thickness of 5 km. The basement shows the same velocity distribution as in TAP and GB, suggesting a common nature and origin. According to its seismic structure, we interpret this basement as highly serpentinized, exhumed mantle. In contrast, the CPR and SAP show evidences for the presence of a well-developed, 6-7 km-thick oceanic crust, underlying the sedimentary sequence. Profile P2 is 256 km long, and trends S-N from the easternmost SAP beyond the NW Moroccan margin, crossing the Gulf of Cadiz imbricated wedge and the Portimao bank ending at the

  9. State of Hydration of the Juan de Fuca Plate Along the Cascadia Deformation Front from Controlled-Source Wide-Angle Seismic Data

    Science.gov (United States)

    Canales, J. P.; Carbotte, S. M.; Carton, H. D.; Nedimovic, M. R.

    2014-12-01

    Understanding the structure and state of hydration of the young Juan de Fuca (JdF) Plate prior to being subducted beneath Cascadia is important because water incorporated into the downgoing plate plays a critical role in many subduction zone processes. Here we present the structure of the JdF plate along a ~400-km-long wide-angle seismic profile extending from offshore Northern WA to offshore Central OR, ~10 km seaward from the Cascadia deformation front (CDF). Vp in the lower crust decreases from north to south: 7.0-7.1 km/s north of 46°N, and 6.85-6.95 km/s south of 45°30'N. Vp in the upper 2.5 km of the mantle is highest north of 46°50N (7.85-7.95 km/s) and south of the 45°N (7.85-8.1 km/s). In between these latitudes, mantle Vp is 7.75-7.85 km/s north of 45°45'N, and reaches a minimum value of 7.55 km/s at 45°15'N. MCS images across the southern part of the plate show evidence for faulting in the lower crust and upper mantle while images across the northern part of the plate do not [Han et al., this meeting]. Therefore we interpret the along-CDF variations in lower crustal and upper mantle velocity largely resulting from the increasing north-to-south effect of bending-related faulting. Taking into account plate age, inferred thermal structure, and expected mantle anisotropy, we explore end-member scenarios on the amount of fracturing and water stored in the lower crust and uppermost mantle of the JdF plate off the CDF. Assuming that Vp variations are due to fractures containing free H2O, we estimate that lower crust/upper mantle porosity increases from <0.1% north of 46°N to 0.15-0.25% to the south of this latitude, with free H2O content at these depths reaching a maximum of 0.08 wt% between 45°15'-30'N. At the other end of the spectrum, Vp variations may be explained by fractures filled-in with hydration products such as serpentine; in which case we estimate a porosity south of 46°N as large as 5-9%, with chemically-bounded H2O content reaching a

  10. 连续式跨声速风洞大开角扩散段设计方法研究概述%A review of design methods of continuous transonic wind tunnel's wide-angle diffuser

    Institute of Scientific and Technical Information of China (English)

    李红喆; 廖达雄; 丛成华

    2012-01-01

    随着我国自主研发大飞机项目的启动,对相应的高性能大型连续式跨声速风洞这一基础试验平台建设提出了日趋紧迫的需求.大开角扩散段在减小风洞尺寸的同时会引起气流分离,扩散段形状和内部整流装置的合理设计有着重要的意义.首先阐述大开角扩散段在连续式跨声速风洞中的作用,然后介绍了大开角扩散段在国外连续式风洞中的应用情况、布置位置和整流方式,主要分析比较目前几种大开角扩散段内阻尼网的设计方法,总结出一种最为优化的设计方案.最后对国内大型连续式跨声速风洞大开角扩散段的设计提出了几点建议.%The startup of large airplane project is starving for fine capability of capital continuous transonic wind tunnel facility. Wide-angle diffuser reduces the scale of the wind tunnel, but results in flow separation. The disposal and design of this section are important. This paper expatiates the effect of wide-angle diffuser, and then introduces its application instances oversea and ordinary disposal position. Emphasis on the design methods of screens in wide-angle diffuser to summarize a most optimized design scheme. Finally, puts forward some advises for the design of wide-angle diffuser in national continuous transonic wind tunnel.

  11. Selecting Your First Telescope.

    Science.gov (United States)

    Harrington, Sherwood

    1982-01-01

    Designed for first-time telescope purchasers, provides information on how a telescope works; major telescope types (refractors, reflectors, compound telescopes); tripod, pier, altazimuth, and equatorial mounts; selecting a telescope; visiting an astronomy club; applications/limitations of telescope use; and tips on buying a telescope. Includes a…

  12. The molecular pathway to ZIF-7 microrods revealed by in situ time-resolved small- and wide-angle X-ray scattering, quick-scanning extended X-ray absorption spectroscopy, and DFT calculations.

    Science.gov (United States)

    Goesten, Maarten; Stavitski, Eli; Pidko, Evgeny A; Gücüyener, Canan; Boshuizen, Bart; Ehrlich, Steven N; Hensen, Emiel J M; Kapteijn, Freek; Gascon, Jorge

    2013-06-10

    We present an in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and quick-scanning extended X-ray absorption fine-structure (QEXAFS) spectroscopy study on the crystallization of the metal-organic framework ZIF-7. In combination with DFT calculations, the self-assembly and growth of ZIF-7 microrods together with the chemical function of the crystal growth modulator (diethylamine) are revealed at all relevant length scales, from the atomic to the full crystal size.

  13. Watching Nanoparticles Form: An In Situ (Small-/Wide-Angle X-ray Scattering/Total Scattering) Study of the Growth of Yttria-Stabilised Zirconia in Supercritical Fluids

    DEFF Research Database (Denmark)

    Tyrsted, Christoffer; Pauw, Brian; Jensen, Kirsten Marie Ørnsbjerg

    2012-01-01

    Understanding nanoparticle formation reactions requires multitechnique in situ characterisation, since no single characterisation technique provides adequate information. Here, the first combined small-angle X-ray scattering (SAXS)/wide-angle X-ray scattering (WAXS)/total-scattering study of nano...... of nanoparticle formation is presented. We report on the formation and growth of yttria-stabilised zirconia (YSZ) under the extreme conditions of supercritical methanol for particles with Y2O3 equivalent molar fractions of 0, 4, 8, 12 and 25%....

  14. Robotic Telescopes

    Science.gov (United States)

    Akerlof, C. W.

    2001-05-01

    Since the discovery of gamma-ray bursts, a number of groups have attempted to detect correlated optical transients from these elusive objects. Following the flight of the BATSE instrument on the Compton Gamma-Ray Observatory in 1991, a prompt burst coordinate alert service, BACODINE (now GCN) became available to ground-based telescopes. Several instruments were built to take advantage of this facility, culminating in the discovery of a bright optical flash associated with GRB990123. To date, that single observation remains unique - no other prompt flashes have been seen for a dozen or so other bursts observed with comparably short response times. Thus, GRB prompt optical luminosities may be considerably dimmer than observed for the GRB990123 event or even absent altogether. A new generation of instruments is prepared to explore these possibilties using burst coordinates provided by HETE-2, Swift, Ballerina, Agile and other satellite missions. These telescopes have response times as short as a few seconds and reach limiting magnitudes, m_v 20, guaranteeing a sensitivity sufficient to detect the afterglow many hours later. Results from these experiments should provide important new data about the dynamics and locale of GRBs.

  15. 一种宽频宽角圆极化一维相扫天线阵%A broadband wide angle circularly polarized one-dimensional phase scanning antenna array

    Institute of Scientific and Technical Information of China (English)

    陈谦; 李磊; 张小林

    2014-01-01

    基于改进型Vivaldi天线单元,采用4单元十字交叉组合构成圆极化天线,并通过增加耦合金属立柱改善天线轴比,设计了一种超宽频宽角覆盖圆极化直线阵。该天线在1.25-4.1 GHz频段电压驻波比(VSWR)小于2,在1.6-3.6 GHz频段轴比小于3 dB,在垂直扫描方向具备宽角覆盖能力,具备较高的工程应用价值。%Based on improved Vivaldi antenna unit, using four crossed units constitutes a circularly polarized antenna, further improving axial ratio (AR) by adding the coupling metal columns, an ultra-broadband wide-angle circularly polarized linear an-tenna array is designed. The voltage standing wave ratio (VSWR) of the antenna is less than 2 at the frequency range of 1.25 to 4.1 GHz. Meanwhile, the AR is less than 3 dB at the frequency range of 1.6 to 3.6 GHz. This antenna has very wide angle cover-age ability, and has high engineering value.

  16. Holographic telescope

    Science.gov (United States)

    Odhner, Jefferson E.

    2016-07-01

    Holographic optical elements (HOEs) work on the principal of diffraction and can in some cases replace conventional optical elements that work on the principal of refraction. An HOE can be thinner, lighter, can have more functionality, and can be lower cost than conventional optics. An HOE can serve as a beam splitter, spectral filter, mirror, and lens all at the same time. For a single wavelength system, an HOE can be an ideal solution but they have not been widely accepted for multispectral systems because they suffer from severe chromatic aberration. A refractive optical system also suffers from chromatic aberration but it is generally not as severe. To color correct a conventional refractive optical system, a flint glass and a crown glass are placed together such that the color dispersion of the flint and the crown cancel each other out making an achromatic lens (achromat) and the wavelengths all focus to the same point. The color dispersion of refractive lenses and holographic lenses are opposite from each other. In a diffractive optical system, long wavelengths focus closer (remember for HOEs: RBM "red bends more") than nominal focus while shorter wavelengths focus further out. In a refractive optical system, it is just the opposite. For this reason, diffractives can be incorporated into a refractive system to do the color correction and often cut down on the number of optical elements used [1.]. Color correction can also be achieved with an all-diffractive system by combining a holographic optical element with its conjugate. In this way the color dispersion of the first holographic optical element can be cancelled by the color dispersion of the second holographic optic. It is this technique that will be exploited in this paper to design a telescope made entirely of holographic optical elements. This telescope could be more portable (for field operations) the same technique could be used to make optics light enough for incorporation into a UAV.

  17. 广角图像畸变校正算法的研究与实现%RESEARCH AND IMPLEMENTATION OF CORRECTION ALGORITHM FOR WIDE-ANGLE IMAGE DISTORTION

    Institute of Scientific and Technical Information of China (English)

    吴开兴; 段马丽; 张惠民; 王鹏

    2014-01-01

    为了校正广角图像的非线性畸变,提出一种新的数字校正方法来消除畸变。首先利用网格模板校正的方法,根据畸变图与理想图对应像素点的映射关系,得到畸变图像点在x轴和y轴方向上的偏移量。然后采用三次B插值函数对曲面插值,得到畸变像素点的偏移量曲面,由偏移量曲面和畸变点的坐标实现各像素点的坐标变换。最后通过双线性插值法完成灰度重建得到无畸变的图像,从而实现对广角图像的校正。为了测试该算法的速度性能和可靠性等指标,在DSP平台上运行此算法。实验结果表明该算法能够对广角畸变图像进行快速有效的校正。%In order to correct nonlinear distortion of wide-angle images, we propose a new digital correction method to eliminate the distortion.First, it makes use of grid template correction method to obtain the offset of distorted image points along X-and Y-axes directions according to the mapping relation between the corresponding pixels of distortion image and ideal figure.Then, it uses the cubic B-spline interpolation function to interpolate the surface, and gets the offset surface of the distorted pixels.According to the offset surface and the coordinate of distorted points, it realises the transformation of coordinate of each pixel.At last, a perfect image without distortion is obtained by the completion of grayscale reconstruction with bilinear interpolation, so as to achieve the correction on wide-angle images.In order to test the speed performance and the reliability of the algorithm, we run it on DSP platform.The experimental results show that this algorithm can make fast and effective correction on wide-angle distortion images.

  18. Telescope Array Control System Based on Wireless Touch Screen Platform

    Science.gov (United States)

    Fu, X. N.; Huang, L.; Wei, J. Y.

    2016-07-01

    GWAC (Ground-based Wide Angle Cameras) are the ground-based observational instruments of the Sino-French cooperation SVOM (Space Variable Objects Monitor) astronomical satellite, and Mini-GWAC is a pathfinder and supplement of GWAC. In the context of the Mini-GWAC telescope array, this paper introduces the design and implementation of a kind of telescope array control system, which is based on wireless serial interface module to communicate. We describe the development and implementation of the system in detail in terms of control system principle, system hardware structure, software design, experiment, and test. The system uses the touch-control PC which is based on the Windows CE system as the upper-computer, the wireless transceiver module and PLC (Programmable Logic Controller) as the core. It has the advantages of low cost, reliable data transmission, and simple operation. So far, the control system has been applied to Mini-GWAC successfully.

  19. Si nanowire array solar cells with efficient wide-angle photovoltaic conversion%硅纳米线阵列光伏电池及其广角光伏转换

    Institute of Scientific and Technical Information of China (English)

    吕文辉; 张军; 邵乐喜

    2012-01-01

    采用金属援助刻蚀和溶液填充的方法,构筑了原理型Si/导电聚合物(聚3,4-乙撑二氧噻吩:聚苯乙烯磺酸盐,PEDOT1 PSS)核壳纳米线阵列光伏电池。电池的光伏转换效率不依赖于入射光强,达到了6.8%。改变入射光角度,表征了电池的广角光伏转换性能。入射角在45°范围内的有效光电转换效率相对于正入射的光伏转换效率仅降低12%。实验结果表明,纳米线阵列结构的光伏电池有益于广角太阳能转换。%The efficient Si/conducting polymer of poly(3,4-ethylenedioxythiophene) :poly(styrenesulfonate) (PEDOT: PSS) core/shell nanowire array solar cells have been fabricated by metal-assisted Si chemical etching followed by a PEDOT: PSS solution filling and drying process. The power conversion efficiency (PCE) of the hybrid solar cell is independent of incident intensity and reaches 6. 8%. The wide-angle photovoltaic conversion property is characterized by changing incident angle. The conversion efficiency with the incident angle less than 45° is only reduced by 12% compared with under nromal incidance. The hybrid solar cells show excellent wide-angle photovoltaic conversion performance.

  20. 连续式跨声速风洞大开角段整流装置设计数值模拟%Numerical simulation of flow conditioning device design in wide angle diffuser of continuous transonic wind tunnels

    Institute of Scientific and Technical Information of China (English)

    李红喆; 廖达雄; 丛成华

    2015-01-01

    Large area expansion can be achieved effectively by wide angle diffusers in wind tunnels, while the airflow separation may occur at the same time. In order to ensure the flow field quality, the sep—aration must be suppressed. Utilizing damp—screens with reasonable parameters is a valid method in engi—neering. With the background of 0. 6m continuum transonic wind tunnel, so as to test the engineering de—sign method of damp—screens, we verify the preliminary result by the method through the way of numerical simulation. From the calculation, by taking the scheme 3—4, loss coefficients for two screens are 1. 6 and 1. 0 respectively, the RMS value at the outlet of the wide angle diffuser will be 14. 5% ; considering the in—fluence by the environment and adjusting the two coefficients to 0. 8 and 1. 0, the RMS value will be 16. 2% . The research indicates that, the engineering design method, in addition to numerical simulations, can be effectively applied in the design of wide angle diffusers. Suppressing the airflow separation, reduc—ing the pressure loss, and improving the exit velocity uniformity can be achieved simultaneously.%采用阻尼网对大开角段内的气流分离进行控制,并合理设置其参数,是工程上有效的方法之一。为验证阻尼网工程设计方法的可靠性,以0.6m 连续式跨声速风洞为背景,通过数值模拟,对工程设计方法的初步结果进行了验证,并在此基础上结合大开角段布置环境对阻尼网参数进行了优化。由计算结果知,采用方案3—4(两层阻尼网损失系数分别为1.6 和 1.0)时,大开角段出口截面的速度均方根偏差值(RMS)为14.5%;考虑布置环境影响,调整两层阻尼网损失系数至0.8和1.0 时,RMS 值为16.2%。研究结果表明,阻尼网工程设计方法结合数值模拟可以有效地应用于大开角段整流装置的设计,达到了抑制大开角段内气流分离,降低压力损失,提高出口速度均匀性的设计目标。

  1. Design of wide-angle projection lens for 4k digital projector%4k 数字放映机广角放映镜头的设计

    Institute of Scientific and Technical Information of China (English)

    刘宵婵; 陈琛; 宋涛; 张禹; 李维善; 刘红军

    2014-01-01

    To meet the need of 4k short distance movie projection ,a wide-angle projection lens was designed ,which is suitable for projectors with three-digital-micromirror-device (DMD) chips .The largest projection ratio could be 0 .75∶1 ,the relative aperture is 1/2 .2 ,the invert-ed telephoto ratio is 4 .6∶1 .At the Nyquist frequency of 66lp/mm ,the resolution of center field is 0 .42 ,and the resolution of marginal field is 0 .25 .T he max lateral chromatic aberration is 3 .7 μm ,w hich is less than 0 .5 pixel ,and the max distortion is 2 .5% .T he feature of invert-ed telephoto was deeply analyzed ,and the methods for choosing structure ,distributing focal power and calculating key parameters were provided in the paper ,additional ,the issues nee-ding pay attention during aberration correction were contained .Finally ,a wide-angle projec-tion lens with high resolution which could meet all the indices was designed ,besides that ,the lens has the feature of easy structure ,low cost and high quality .%为满足4k电影的短距离放映需求,设计一款广角放映镜头,可适配于采用三芯片DMD技术的放映机,最大投射比可达0.75∶1,相对孔径为1/2.2,反远比为4.6∶1,在66lp/mm的Nyquist频率处,MTF值为0.42,边缘视场MTF值为0.25。最大横向色差为3.7μm<0.5pixel,最大畸变为2.5%。分析了反远距形式的特点,给出了合理选型、分配光焦度和计算关键技术参数的方法,以及像差校正过程中应注意的问题。最终设计出了符合设计指标的具有高分辨率的广角放映镜头,该镜头结构简单、成本低。

  2. Crustal Structure, Seismic Anisotropy and Deformations of the Ediacaran/Cambrian of the Małopolska Block in SE Poland Based on Data from Two Seismic Wide-Angle Experiments

    Science.gov (United States)

    Środa, Piotr

    2017-04-01

    The area of SE Poland represents a complex contact of tectonic units of different consolidation age—from the Precambrian East European Craton, through Palaeozoic West European Platform (including Małopolska Block) to Cenozoic Carpathians and Carpathian Foredeep. In order to investigate the anisotropic properties of the upper crust of the Małopolska Block and their relation to tectonic evolution of the area, two seismic datasets were used: seismic wide-angle off-line recordings from POLCRUST-01 deep seismic reflection profile and recordings from active deep seismic experiment CELEBRATION 2000. During acquisition of deep reflection seismic profile POLCRUST-01 in 2010, a 35-km-long line of 14 recorders (PA-14), oriented perpendicularly to the profile, was deployed to record the refractions from the upper crust (Pg) at wide range of azimuths. These data were used for an analysis of the azimuthal anisotropy of the MB with the modified delay-time inversion method. The results of modelling of the off-line refractions from the MB suggest 6% HTI anisotropy of the Cambrian/Ediacaran basement, with 130º azimuth of the fast velocity axis and mean Vp of 4.9 km/s. To compare this result with previous, independent information about anisotropy at larger depth, a subset of previously modelled data from CELEBRATION 2000 experiment, recorded in the MB area, was also analysed by inversion. The recordings of Pg phase at up to 120 km offsets were analysed using anisotropic delay-time inversion, providing information down to 12 km depth. The CELEBRATION 2000 model shows 9% HTI anisotropy with 126º orientation of the fast axis. Thus, local-scale anisotropy of this part of MB confirms the large-scale anisotropy suggested by previous studies based on data from a broader area and larger depth interval. The azimuthal anisotropy (i.e. HTI symmetry of the medium) is interpreted as a result of strong compressional deformation during the accretion of terranes to the EEC margin, leading to

  3. Crustal structure and evolution of the southern Juan de Fuca plate from wide-angle seismic data: Insights into the hydration state of the incoming plate off Cascadia subduction zone

    Science.gov (United States)

    Horning, G.; Canales, J. P.; Carbotte, S. M.; Nedimovic, M. R.; Carton, H. D.

    2014-12-01

    A multi-channel seismic reflection and wide-angle refraction seismic experiment was conducted on the Juan de Fuca (JdF) plate to investigate the evolution of the plate from accretion to its subduction at the Cascadia margin. Hydration of the upper crust (UC) of the JdF Plate is well documented, but the state of hydration of the lower crust (LC) and upper mantle (UM] remains to be investigated. A 2D P-wave velocity model of the plate is derived from a joint reflection-refraction travel-time inversion of wide-angle seismic data. Stacked MCS reflection images together with modeled sedimentary velocities define an increasing thickness of sedimentary cover of up to 2.7km. Evidence for bending-related faulting is identified in coincident MCS images both indirectly as faulting in the sedimentary layer [Gibson, et al., this meeting] and directly as dipping crustal reflectors [Han et al., this meeting]. Three first order features are evident in the patterns of crustal velocity variations along the profile. 1: Crustal velocities at 150-250 km landward of the spreading ridge (~5 Ma age) show reduced velocities up to -0.20 km/s in comparison to velocities in younger crust (~3 Ma) 100-150 km from the ridge. This decrease in velocities is coincident with a propagator wake. 2: Upper crustal velocities begin to increase at 170km from the deformation front (DF), which coincides with the first evidence of faulting from sedimentary offsets. Crustal velocities start a decreasing trend at 80km from the DF where fault throws are seen to begin increasing trend landward. 3: UC velocities in the region of directly imaged crustal faulting (40km from trench) increase ~0.5km/s at the DF, while LC velocities decrease ~0.3km/s. The contrasting behavior in the upper and lower crust may indicate that bending promotes hydrothermal circulation in the outer rise. Circulation may be vigorous enough within the sediments/UC so that any residual shallow porosity is clogged with alteration products

  4. Study report of design technology of transonic wind tunnel's wide angle diffuser%跨超声速风洞大开角段设计技术研究

    Institute of Scientific and Technical Information of China (English)

    丛成华; 陈振华; 彭强

    2011-01-01

    跨超声速风洞大开角段设计技术研究对于提高大开角段的安全性能与改进稳定段入口气流质量有着重大意义.由于影响大开角段性能的参数较多,完全通过试验方法进行设计的成本过高.本文通过数值模拟方法,结合适当的边界条件,对不同参数的大开角段进行了模拟,从数值模拟的结果可以看到,孔板开孔率和扩开角对大开角段性能有显著影响,通过比较得出了较为合理的参数匹配.这表明本文所用的方法用于大开角段气动设计是可行的,这为数值模拟方法应用于风洞部段气动设计创造了一定的条件.%Design technology of transonic wind tunnel's wide angle diffuser(WAD) plays an important role in the improvement of the diffuser's security.This paper is about study of the design technology of transonic wind tunnel's WAD.It presents the control equations and boundary conditions for numerical simulation.Then the details of numerical results are given.In the last, conclusions about wide angle diffuser are listed that angle of diffuser and open - area ratio of perforated plate which could significantly reduce or eliminate steady separation must be exactly set.These parameters inside the WAD could produce a more uniform velocity profile entering setting chamber.Conclusions state the importance and feasibility of CFD in aero dynamical design of wind tunnel.

  5. A Two Element Laminar Flow Airfoil Optimized for Cruise. M.S. Thesis

    Science.gov (United States)

    Steen, Gregory Glen

    1994-01-01

    Numerical and experimental results are presented for a new two-element, fixed-geometry natural laminar flow airfoil optimized for cruise Reynolds numbers on the order of three million. The airfoil design consists of a primary element and an independent secondary element with a primary to secondary chord ratio of three to one. The airfoil was designed to improve the cruise lift-to-drag ratio while maintaining an appropriate landing capability when compared to conventional airfoils. The airfoil was numerically developed utilizing the NASA Langley Multi-Component Airfoil Analysis computer code running on a personal computer. Numerical results show a nearly 11.75 percent decrease in overall wing drag with no increase in stall speed at sailplane cruise conditions when compared to a wing based on an efficient single element airfoil. Section surface pressure, wake survey, transition location, and flow visualization results were obtained in the Texas A&M University Low Speed Wind Tunnel. Comparisons between the numerical and experimental data, the effects of the relative position and angle of the two elements, and Reynolds number variations from 8 x 10(exp 5) to 3 x 10(exp 6) for the optimum geometry case are presented.

  6. Modeling the amorphous structure of mechanically alloyed Ti{sub 50}Ni{sub 25}Cu{sub 25} using anomalous wide-angle x-ray scattering and reverse Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.br [Departamento de Física, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Poffo, C.M. [Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Souza, S.M. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Machado, K.D. [Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba, Paraná (Brazil); Trichês, D.M. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Grandi, T.A. [Departamento de Física, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Biasi, R.S. de [Seção de Engenharia Mecânica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)

    2013-09-01

    An amorphous Ti{sub 50}Ni{sub 25}Cu{sub 25} alloy was produced by 19 h of mechanical alloying. Anomalous wide angle x-ray scattering data were collected at six energies and six total scattering factors were obtained. By considering the data collected at two energies close to the Ni and Cu K edges, two differential anomalous scattering factors about the Ni and Cu atoms were obtained, showing that the chemical environments around these atoms are different. Eight factors were used as input data to the reverse Monte Carlo method used to compute the partial structure factors S{sub Ti3Ti}(K), S{sub Ti–Cu}(K), S{sub Ti–Ni}(K), S{sub Cu3Cu}(K), S{sub Cu–Ni}(K) and S{sub Ni–Ni}(K) and the partial pair distribution functions G{sub Ti3Ti}(r), G{sub Ti–Cu}(r), G{sub Ti–Ni}(r), G{sub Cu3Cu}(r), G{sub Cu–Ni}(r) and G{sub Ni–Ni}(r). From the RMC final atomic configuration and G{sub ij}(r) functions, the coordination numbers and interatomic atomic distances for the first neighbors were determined.

  7. Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great Sumatra-Andaman earthquake: Results from seismic refraction and wide-angle reflection surveys and thermal modeling

    CERN Document Server

    Klingelhoefer, Frauke; Ladage, S; Dessa, J -X; Graindorge, David; Franke, D; André, C; Permana, Haryadi; Yudistira, T; Chauhan, Ajay; 10.1029/2009JB006569

    2010-01-01

    The 26 December 2004 Sumatra earthquake (Mw = 9.1) initiated around 30 km depth and ruptured 1300 km of the Indo-Australian Sunda plate boundary. During the Sumatra OBS (ocean bottom seismometer) survey, a wide angle seismic profile was acquired across the epicentral region. A seismic velocity model was obtained from combined travel time tomography and forward modeling. Together with reflection seismic data from the SeaCause II cruise, the deep structure of the source region of the great earthquake is revealed. Four to five kilometers of sediments overlie the oceanic crust at the trench, and the subducting slab can be imaged down to a depth of 35 km. We find a crystalline backstop 120 km from the trench axis, below the fore arc basin. A high velocity zone at the lower landward limit of the raycovered domain, at 22 km depth, marks a shallow continental Moho, 170 km from the trench. The deep structure obtained from the seismic data was used to construct a thermal model of the fore arc in order to predict the li...

  8. On diversity performance of two-element coupling element based antenna structure for mobile terminal

    DEFF Research Database (Denmark)

    Al-Hadi, Azremi Abdullah; Toivanen, Juha; Laitinen, Tommi

    2010-01-01

    fading. The main challenge of antenna diversity in practical application is the integration of multiple antennas on a small ground plane. Two-element antenna structure based on coupling element antenna concept for diversity application has been studied in previous work and it has shown to be feasible......In wireless communication systems, multipath interference has a significant impact on system design and performance. Fast fading is caused by the coherent summation of one or more echoes from many reflection points reaching the receive antenna. Antenna diversity can be used to mitigate multipath...... for low frequency diversity application with stable and low envelope correlation across wide frequency range. The studied structure has been tuned to be operating at 1600 MHz for measurement evaluation purpose. This paper presents an analysis of diversity performance of the structure in terms...

  9. The SOFIA Telescope

    CERN Document Server

    Krabbe, A

    2000-01-01

    The SOFIA telescope as the heart of the observatory is a major technological challenge. I present an overview on the astro-nomical and scientific requirements for such a big airborne observatory and demonstrate the impact of these requirements on the layout of SOFIA, in particular on the telescope design as it is now. Selected components of the telescope will be de-scribed in their context and functionality. The current status of the telescope is presented.

  10. High-Flying Telescope

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    Scientists at the Space Telescope Science Institute,which operates the Hubble Space Telescope,have proposed a new telescope that would have twice the resolution of Hubble at about one-tenth the cost. It would hover seven miles above Earth,dangling below a football-field-size helium balloon

  11. Auto Adjusting Astronomical Telescope

    Directory of Open Access Journals (Sweden)

    Rohit R. Ghalsasi

    2014-04-01

    Full Text Available Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.

  12. ATST telescope mount: telescope of machine tool

    Science.gov (United States)

    Jeffers, Paul; Stolz, Günter; Bonomi, Giovanni; Dreyer, Oliver; Kärcher, Hans

    2012-09-01

    The Advanced Technology Solar Telescope (ATST) will be the largest solar telescope in the world, and will be able to provide the sharpest views ever taken of the solar surface. The telescope has a 4m aperture primary mirror, however due to the off axis nature of the optical layout, the telescope mount has proportions similar to an 8 meter class telescope. The technology normally used in this class of telescope is well understood in the telescope community and has been successfully implemented in numerous projects. The world of large machine tools has developed in a separate realm with similar levels of performance requirement but different boundary conditions. In addition the competitive nature of private industry has encouraged development and usage of more cost effective solutions both in initial capital cost and thru-life operating cost. Telescope mounts move relatively slowly with requirements for high stability under external environmental influences such as wind buffeting. Large machine tools operate under high speed requirements coupled with high application of force through the machine but with little or no external environmental influences. The benefits of these parallel development paths and the ATST system requirements are being combined in the ATST Telescope Mount Assembly (TMA). The process of balancing the system requirements with new technologies is based on the experience of the ATST project team, Ingersoll Machine Tools who are the main contractor for the TMA and MT Mechatronics who are their design subcontractors. This paper highlights a number of these proven technologies from the commercially driven machine tool world that are being introduced to the TMA design. Also the challenges of integrating and ensuring that the differences in application requirements are accounted for in the design are discussed.

  13. Crustal architecture and deep structure of the Namibian continental shelf and adjacent oceanic basins around the landfall of Walvis Ridge from wide-angle seismic and marine magnetotelluric data

    Science.gov (United States)

    Planert, L.; Behrmann, J.; Jegen, M.; Heincke, B.; Jokat, W.; Bialas, J.; Marti, A.

    2012-12-01

    The opening of the South Atlantic ocean basin resulted in voluminous magmatism on the conjugate continental margins of Africa and South America, including the formation of the Parana and Entendeka large igneous provinces (LIPs), the formation of up to 100 km wide volcanic wedges characterized by seaward dipping reflector sequences (SDRs), as well as the formation of paired hotspot tracks on the rifted African and South American plates, the Walvis Ridge and the Rio Grande Rise. Hence, the passive margins bordering the South Atlantic are today considered as type examples for models involving hotspot related continental break-up. However, the presence of volcanic features (SDRs, LIPs) appears to be limited south of the hotspot trails. The resulting segmentation of the margins offers a prime opportunity to study the magmatic signal in space and time, and investigate the interrelation with rift-related deformation. A globally significant question to be adressed here is whether magmatism is the driving force for continental break-up, or whether even rifting with abundant hotspot related magmatism is in principle in response to crustal and lithospheric stretching. In 2010/11, a combination of on-/offshore wide-angle seismic, marine magnetotelluric and on-/offshore seismological data were acquired around the landfall of Walvis Ridge at the Namibian passive continental margin. The set of experiments was designed to provide crustal velocity and conductivity information and to investigate the structure of the upper mantle. In particular, we aimed at identifying deep fault zones and variations in Moho depth, the presence of interleaved sediment layers in SDR sequences as well as magmatic intrusions and underplated material near the continent-ocean transition. The sedimentary portions down to the igneous basement were additionally constrained by coincident single-channel reflection seismic data. Here, we present preliminary results for two wide-angle seismic transects and first

  14. The Cherenkov Telescope Array Large Size Telescope

    CERN Document Server

    Ambrosi, G; Baba, H; Bamba, A; Barceló, M; de Almeida, U Barres; Barrio, J A; Bigas, O Blanch; Boix, J; Brunetti, L; Carmona, E; Chabanne, E; Chikawa, M; Colin, P; Conteras, J L; Cortina, J; Dazzi, F; Deangelis, A; Deleglise, G; Delgado, C; Díaz, C; Dubois, F; Fiasson, A; Fink, D; Fouque, N; Freixas, L; Fruck, C; Gadola, A; García, R; Gascon, D; Geffroy, N; Giglietto, N; Giordano, F; Grañena, F; Gunji, S; Hagiwara, R; Hamer, N; Hanabata, Y; Hassan, T; Hatanaka, K; Haubold, T; Hayashida, M; Hermel, R; Herranz, D; Hirotani, K; Inoue, S; Inoue, Y; Ioka, K; Jablonski, C; Kagaya, M; Katagiri, H; Kishimoto, T; Kodani, K; Kohri, K; Konno, Y; Koyama, S; Kubo, H; Kushida, J; Lamanna, G; Flour, T Le; López-Moya, M; López, R; Lorenz, E; Majumdar, P; Manalaysay, A; Mariotti, M; Martínez, G; Martínez, M; Mazin, D; Miranda, J M; Mirzoyan, R; Monteiro, I; Moralejo, A; Murase, K; Nagataki, S; Nakajima, D; Nakamori, T; Nishijima, K; Noda, K; Nozato, A; Ohira, Y; Ohishi, M; Ohoka, H; Okumura, A; Orito, R; Panazol, J L; Paneque, D; Paoletti, R; Paredes, J M; Pauletta, G; Podkladkin, S; Prast, J; Rando, R; Reimann, O; Ribó, M; Rosier-Lees, S; Saito, K; Saito, T; Saito, Y; Sakaki, N; Sakonaka, R; Sanuy, A; Sasaki, H; Sawada, M; Scalzotto, V; Schultz, S; Schweizer, T; Shibata, T; Shu, S; Sieiro, J; Stamatescu, V; Steiner, S; Straumann, U; Sugawara, R; Tajima, H; Takami, H; Tanaka, S; Tanaka, M; Tejedor, L A; Terada, Y; Teshima, M; Totani, T; Ueno, H; Umehara, K; Vollhardt, A; Wagner, R; Wetteskind, H; Yamamoto, T; Yamazaki, R; Yoshida, A; Yoshida, T; Yoshikoshi, T

    2013-01-01

    The two arrays of the Very High Energy gamma-ray observatory Cherenkov Telescope Array (CTA) will include four Large Size Telescopes (LSTs) each with a 23 m diameter dish and 28 m focal distance. These telescopes will enable CTA to achieve a low-energy threshold of 20 GeV, which is critical for important studies in astrophysics, astroparticle physics and cosmology. This work presents the key specifications and performance of the current LST design in the light of the CTA scientific objectives.

  15. Joint inversion of multichannel seismic reflection and wide-angle seismic data: Improved imaging and refined velocity model of the crustal structure of the north Ecuador-south Colombia convergent margin

    Science.gov (United States)

    Agudelo, W.; Ribodetti, A.; Collot, J.-Y.; Operto, S.

    2009-02-01

    Improving seismic imaging of the crust is essential for understanding the structural factors controlling subduction zones processes. We developed a processing work flow based on the combined analysis of multichannel seismic reflection (MCS) and wide angle (WA) reflection/refraction data to derive both shallow and deep velocities suitable for prestack depth migration and to construct a blocky velocity model integrating all identifiable seismic phases contained in MCS and WA data. We apply this strategy to the study of the north Ecuador-SW Colombia subduction margin to improve the imaging and geostructural interpretation of a splay fault and surrounding outer and inner margin wedges. Results show improvements over tomographic inversion of WA data only, such as (1) sediment velocity variation across the trench and margin slope that correlates with lateral lithologic changes, tectonic compaction and effect of mass wasting processes; (2) a two-layer velocity structure of the inner wedge basement that is consistent with the crust of an oceanic plateau; (3) a complex velocity structure of the outer wedge basement that consists of a deep, high-velocity (5.0-5.5 km s-1) core and a low-velocity zone (3.8-5.0 km s-1) associated with the major splay fault; (4) a ˜1.3-km-thick, low-velocity (3.5-4.0 km s-1) subduction channel that extends beneath the margin outer wedge. Both the splay fault and subduction channel are expected to direct fluid flows; and (5) downdip velocity increase (5-6 km s-1) in the subducting oceanic crust associated with a low (7.8 km s-1) upper mantle velocity, possibly reflecting changes in rock nature or properties.

  16. Crustal structure of seismic velocity in southern Tibet and east-westward escape of the crustal material--An example by wide-angle seismic profile from Peigu Tso to Pumoyong Tso

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Zhongjie; TENG; Jiwen; LI; Yingkang; S.Klemperer

    2004-01-01

    The reflecting events from Moho and other interfaces within the crust are recognized from the wavefield characteristics of P- and S-wave for the 480km long wide-angle seismic profile between Peigu Tso and Pumoyong Tso. Then, seismic crustal structures of P- and S-wave velocities and Poisson ratio under the nearly east-west profile in southern Tibet are interpreted by fitting the observed traveltimes with the calculated ones by forward modelling. Our interpreting results demonstrate that the crustal thickness varies remarkably in the east-west direction, showing a pattern that the crust could be divided into three parts bounded by the west of Dingri and the east of Dinggyê, respectively, where the depth of Moho is about 71km for the western part, about 76km for the middle and about 74km for the eastern. There is one lower velocity layer (LVL) at the bottom of the upper crust with depth of 20-30 km. One of the distinct features is that the thickness of LVL abruptly thins from 24km on the west to 6km on the east. The other is that the velocity variation in the crust along east-west direction for both P- and S-wave displays a feature as quasi-periodic variation. The lower velocity (compared to the average value for the continent of the globe) in the lower crust and three sets of north-southward active normal faults are probably attributed to the coupling process of material delamination in the lower crust, crustal thicking and east-westward escape of the crustal material accompanied with the continental collision between India and Eurasia Plate.

  17. The Africa Millimetre Telescope

    Science.gov (United States)

    Backes, M.; Müller, C.; Conway, J. E.; Deane, R.; Evans, R.; Falcke, H.; Fraga-Encinas, R.; Goddi, C.; Klein Wolt, M.; Krichbaum, T. P.; MacLeod, G.; Ribeiro, V. A. R. M.; Roelofs, F.; Shen, Z. Q.; van Langevelde, H. J.

    It is believed that supermassive black holes are found in the centres of galaxies, including the Milky Way. Still, only indirect evidence has been gathered for the existence of these enigmatic objects that are predicted by the general theory of relativity. With the Event Horizon Telescope, a Very Long Baseline Interferometry network of millimetre-wave (radio) telescopes, it will be possible to directly image the 'shadow' of the event horizon of the black hole at the centre of the Milky Way, Sgr A*. Although the Event Horizon Telescope utilises an extensive network of telescopes, there is a huge gap in the coverage of the u-v-plane for these observations across Africa. We discuss the benefits of adding the Africa Millimetre Telescope to the Event Horizon Telescope and present Mt. Gamsberg in Namibia as the best site for this new and first mm-wave telescope in Africa.

  18. Liverpool Telescope and Liverpool Telescope 2

    Science.gov (United States)

    Copperwheat, C. M.; Steele, I. A.; Barnsley, R. M.; Bates, S. D.; Clay, N. R.; Jermak, H.; Marchant, J. M.; Mottram, C. J.; Piascik, A.; Smith, R. J.

    2016-12-01

    The Liverpool Telescope is a fully robotic optical/near-infrared telescope with a 2-metre clear aperture, located at the Observatorio del Roque de los Muchachos on the Canary Island of La Palma. The telescope is owned and operated by Liverpool John Moores University, with financial support from the UK's Science and Technology Facilities Council. The telescope began routine science operations in 2004 and is a common-user facility with time available through a variety of committees via an open, peer reviewed process. Seven simultaneously mounted instruments support a broad science programme, with a focus on transient follow-up and other time domain topics well suited to the characteristics of robotic observing. Development has also begun on a successor facility, with the working title `Liverpool Telescope 2', to capitalise on the new era of time domain astronomy which will be brought about by the next generation of survey facilities such as LSST. The fully robotic Liverpool Telescope 2 will have a 4-metre aperture and an improved response time. In this paper we provide an overview of the current status of both facilities.

  19. Theoretical study of two-element array of equilateral triangular patch microstrip antenna on ferrite substrate

    Indian Academy of Sciences (India)

    K K Verma; K R Soni

    2005-09-01

    The radiation characteristics of a two-element array of equilateral triangular patch microstrip antenna on a ferrite substrate are studied theoretically by considering the presence of bias magnetic field in the direction of propagation of electromagnetic waves. It is found that the natural modes of propagation in the direction of magnetic field are left- and right-circularly polarized waves and these modes have different propagation constants. In loss-less isotropic warm plasma, this array antenna geometry excites both electromagnetic (EM) and electroacoustic plasma (P) waves in addition to a nonradiating surface wave. In the absence of an external magnetic field, the EM- and P-waves can be decoupled into two independent modes, the electroacoustic mode is longitudinal while the electromagnetic mode is transverse. The far-zone EM-mode and P-mode radiation fields are derived using vector wave function techniques and pattern multiplication approaches. The results are obtained in both plasma medium and free space. Some important antenna parameters such as radiation conductance, directivity and quality factor are plotted for different values of plasma-to-source frequency.

  20. Noninvasive arterial blood pressure waveform monitoring using two- element ultrasound system.

    Science.gov (United States)

    Seo, Joohyun; Pietrangelo, Sabino J; Lee, Hae-Seung; Sodini, Charles G

    2015-04-01

    This work details noninvasive arterial blood pressure (ABP) waveform estimation based on an arterial vessel cross-sectional area measurement combined with an elasticity measurement of the vessel, represented by pulse wave velocity (PWV), using a two-element ultrasound system. The overall ABP waveform estimation is validated in a custom-designed experimental setup mimicking the heart and an arterial vessel segment with two single element transducers, assuming a constant hemodynamic system. The estimation of local PWV using the flow-area method produces unbiased elasticity estimation of the tube in a pressure waveform comparison. The measured PWV using 16 cardiac cycles of data is 8.47 + 0.63 m/s with an associated scaling error of -1.56 + 14.0% in a direct pressure waveform comparison, showing negligible bias error on average. The distension waveform obtained from a complex cross-correlation model estimator (C3M) reliably traces small pressure changes reflected by the diameter change. The excellent agreement of an estimated pressure waveform to the reference pressure waveform suggests the promising potential of a readily available, inexpensive, and portable ABP waveform monitoring device.

  1. 近距离微型广角加力燃烧室点火过程观测系统%Micro and Wide-Angle Observation System Close to Aeroengine Afterburner for Ignition Process

    Institute of Scientific and Technical Information of China (English)

    胡智涌; 段发阶

    2016-01-01

    由于加力燃烧室尾喷口环境恶劣,难以近距离对其进行观测,传统方法采用远距离观测,成像效果不佳.本文提出一种用于可见光波段的微型广角观测系统方案,使用微型相机,与水冷保护管相结合,可直接在尾喷口后1~2 m位置对加力燃烧室点火过程进行观测.相机直径7 mm,水冷管直径可达20~30 mm,视场角最大可达50°.在模拟实验中,对靶标成像清晰,细节明显.通过视觉成像技术对航空发动机加力燃烧室内部区域工作过程进行观测,得到的观测结果可用于对点火、火焰稳定性和燃烧均匀性的定性评价.%Due to the severe environment near to the jet of the afterburner, it is hard to observe.Tradi-tional observation method is remote from the afterburner and the photos are not clear enough.In order to solve this problem, a micro and wide-angle observation system was proposed in this paper.Based on a micro camera and combined with a water-cooling tube, the system is useful for visible spectrum and can be set close to the jet with a distance of 1—2 m.The camera diameter is 7 mm and the water-cooling tube diameter reach to 20—30 mm, and the largest field angle is about 50°.Experimental results show that the images of the system for the target are clear and detailed.The result of vision observation to aero-engine afterburner inner aera is available for the evaluation of ignition and combustion stability and homo-geneity.

  2. The Solar Telescope GREGOR

    Science.gov (United States)

    Volkmer, R.

    2008-09-01

    During the last years the new 1.5m solar telescope GREGOR was assembled at Izania on Tenerife, Spain. The telescope is designed for high-precision measurements of the magnetic field in the solar photosphere and chromosphere with a resolution of 70km on the Sun. The telescope concept offers also high resolution stellar spectroscopy. The telescope is build by a consortium of the Kiepenheuer-Institut für Sonnenphysik, the Astrophysikalische Institut Potsdam, the Institut für Astrophysik Göttingen, Max-Plank-Institut für Sonnensystemforschung and additional international Partners. The telescope is a complete open structure with active cooled main mirror. High performance post-focus instruments in the visible and near IR wavelength acquire high resolution spectra with 2 dimensional spatial resolution and polarimetric information. The commissioning of the telescope will start in 2008 to allow first science observations at the end of 2009.

  3. JWST Pathfinder Telescope Integration

    Science.gov (United States)

    Matthews, Gary W.; Kennard, Scott H.; Broccolo, Ronald T.; Ellis, James M.; Daly, Elizabeth A.; Hahn, Walter G.; Amon, John N.; Mt. Pleasant, Stephen M.; Texter, Scott; Atkinson, Charles B.; McKay, Andrew; Levi, Joshua; Keski-Kuha, Ritva; Feinberg, Lee

    2015-01-01

    The James Webb Space Telescope (JWST) is a 6.5m, segmented, IR telescope that will explore the first light of the universe after the big bang. In 2014, a major risk reduction effort related to the Alignment, Integration, and Test (AI&T) of the segmented telescope was completed. The Pathfinder telescope includes two Primary Mirror Segment Assemblies (PMSA's) and the Secondary Mirror Assembly (SMA) onto a flight-like composite telescope backplane. This pathfinder allowed the JWST team to assess the alignment process and to better understand the various error sources that need to be accommodated in the flight build. The successful completion of the Pathfinder Telescope provides a final integration roadmap for the flight operations that will start in August 2015.

  4. The great Melbourne telescope

    CERN Document Server

    Gillespie, Richard

    2011-01-01

    Erected at Melbourne Observatory in 1869, the telescope was the second largest in the world, designed to explore the nature of the nebulae in the southern skies. Richard Gillespie, head of the History and Technology department at the Melbourne museum has written an entertaining account of the telescope's extraordinary history and tells the story through an amazing cast of characters whose lives intersected with the telescope.

  5. Pointing a solar telescope

    Science.gov (United States)

    Wallace, Patrick

    2016-07-01

    As far as pointing is concerned, a solar telescope is merely an ordinary astronomical telescope but with enhancements for observing solar and coronal features. The paper discusses the additional coordinate systems that need to be supported, shows how to generate the required solar ephemerides (both orbital and physical), and sets out a suitable application programming interface for the telescope control system to use when making solar observations.

  6. The First VERITAS Telescope

    CERN Document Server

    Holder, J; Badran, H M; Blaylock, G; Bradbury, S M; Buckley, J H; Byrum, K L; Carter-Lewis, D A; Celik, O; Chow, Y C K; Cogan, P; Cui, W; Daniel, M K; De la Calle-Perez, I; Dowdall, C; Dowkontt, P; Duke, C; Falcone, A D; Fegan, S J; Finley, J P; Fortin, P; Fortson, L F; Gibbs, K; Gillanders, G; Glidewell, O J; Grube, J; Gutíerrez, K J; Gyuk, G; Hall, J; Hanna, D; Hays, E; Horan, D; Hughes, S B; Humensky, T B; Imran, A; Jung, I; Kaaret, Philip; Kenny, G E; Kieda, D; Kildea, J; Knapp, J; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Linton, E; Little, E K; Maier, G; Manseri, H; Milovanovic, A; Moriarty, P; Mukherjee, R; Ogden, P A; Ong, R A; Perkins, J S; Pizlo, F; Pohl, M; Quinn, J; Ragan, K; Reynolds, P T; Roache, E T; Rose, H J; Schroedter, M; Sembroski, G H; Sleege, G A; Steele, D; Swordy, S P; Syson, A; Toner, J A; Valcarcel, L; Vasilev, V V; Wagner, R; Wakely, S P; Weekes, T C; White, R J; Williams, D A

    2006-01-01

    The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV $\\gamma$-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.

  7. LUTE telescope structural design

    Science.gov (United States)

    Ruthven, Gregory

    1993-01-01

    The major objective of the Lunar Ultraviolet Transit Experiment (LUTE) Telescope Structural Design Study was to investigate the feasibility of designing an ultralightweight 1-m aperture system within optical performance requirements and mass budget constraints. This study uses the results from our previous studies on LUTE as a basis for further developing the LUTE structural architecture. After summarizing our results in Section 2, Section 3 begins with the overall logic we used to determine which telescope 'structural form' should be adopted for further analysis and weight estimates. Specific telescope component analysis showing calculated fundamental frequencies and how they compare with our derived requirements are included. 'First-order' component stress analyses to ensure telescope optical and structural component (i.e. mirrors & main bulkhead) weights are realistic are presented. Layouts of both the primary and tertiary mirrors showing dimensions that are consistent with both our weight and frequency calculations also form part of Section 3. Section 4 presents our calculated values for the predicted thermally induced primary-to-secondary mirror despace motion due to the large temperature range over which LUTE must operate. Two different telescope design approaches (one which utilizes fused quartz metering rods and one which assumes the entire telescope is fabricated from beryllium) are considered in this analysis. We bound the secondary mirror focus mechanism range (in despace) based on these two telescope configurations. In Section 5 we show our overall design of the UVTA (Ultraviolet Telescope Assembly) via an 'exploded view' of the sub-system. The 'exploded view' is annotated to help aid in the understanding of each sub-assembly. We also include a two view layout of the UVTA from which telescope and telescope component dimensions can be measured. We conclude our study with a set of recommendations not only with respect to the LUTE structural architecture

  8. Water-filled telescopes

    CERN Document Server

    Antonello, E

    2014-01-01

    In this short note we discuss the case of the thought experiments on water-filled telescopes and their realizations during 18th and 19th century. The story of those instruments shows that the scientific progress occurs in a curious way, since there was no stringent reason for the construction of a water-filled telescope.

  9. Athermal laser launch telescopes

    NARCIS (Netherlands)

    Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.

    2011-01-01

    ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several

  10. Athermal laser launch telescopes

    NARCIS (Netherlands)

    Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.

    2011-01-01

    ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several o

  11. Optical Design of Spaceborne Low-distortion and Super-wide-angle Aerosol Imager%星载超广角气溶胶探测仪均匀像面性光学设计

    Institute of Scientific and Technical Information of China (English)

    薛庆生

    2012-01-01

    为满足空间遥感的迫切需求,设计了星载低畸变超广角气溶胶探测仪系统.系统中多光谱成像仪的光谱范围为0.860~0.965 μm,全视场角为94°,相对孔径为1∶4,采用反远距结构,系统后工作距离为42 mm.根据反远距结构的像差特点,提出了合理选用易于加工的二次曲面校正畸变,并利用光阑像差产生的有效像差渐晕改善像面照度分布设计方法.运用光学设计软件CODE V和ZEMAX对气溶胶探测仪光学系统进行了光线追迹和优化并对设计结果进行了分析.结果表明,最大畸变为-1.6%,像面上边缘视场的照度大于中心视场照度的46%,光学系统在奈奎斯特频率38.5 lp/mm处的光学传递函数均达到0.59以上,完全满足设计指标要求;体积小,适合空间遥感应用;同时证明了设计方法是可行的.%In order to meet the urgent requirements of space remote sensing, a spaceborne low-distortion and super-wide-angle aerosol imager system is designed. The system is a multi-spectral imager with the working wavelength band from 0. 860 μm to 0. 965 μm, and its full field of view is 94° and the relative aperture is 1 : 4. By using a retrofocus structure, its back working is 42 mm in the optical system. Based on the aberration characteristics of retrofocus structure, methods for correcting distortion and improving the illuminance distribution are proposed. Its distortion is corrected by choosing suitable quadric surface, and the illuminance distribution on image plane is improved by using effective aberration vignetting resulted from stop aberration. Ray tracing, optimization and analysis are performed by CODE V and ZEMAX software. The analysis results demonstrate that the maximum distortion is less than -1. 6% , and the illuminance at edge field of view is higher than that of 46. 9% of central field of view and the MTF is higher than 0. 59 at Nyquist frequency 38. 5 lp/mm, which satisfies the requirement. Its

  12. Resultados preliminares de um sistema de topografia de grande-ângulo usando videoceratógrafo com discos de Plácido Preliminary results of a wide-angle corneal topography system for Placido-based videokeratographers

    Directory of Open Access Journals (Sweden)

    Luis Alberto Vieira de Carvalho

    2008-04-01

    Full Text Available OBJETIVO: Desenvolver a instrumentação e o "software" para topografia de córnea de grande-ângulo usando o tradicional disco de Plácido. O objetivo é permitir o mapeamento de uma região maior da córnea para topógrafos de córnea que usem a técnica de Plácido, fazendo-se uma adaptação simples na mira. MÉTODOS: Utilizando o tradicional disco de Plácido de um topógrafo de córnea tradicional, 9 LEDs (Light Emitting Diodes foram adaptados no anteparo cônico para que o paciente voluntário pudesse fixar o olhar em diferentes direções. Para cada direção imagens de Plácido foram digitalizadas e processadas para formar, por meio de algoritmo envolvendo elementos sofisticados de computação gráfica, um mapa tridimensional completo da córnea toda. RESULTADOS: Resultados apresentados neste trabalho mostram que uma região de até 100% maior pode ser mapeada usando esta técnica, permitindo que o clínico mapeie até próximo ao limbo da córnea. São apresentados aqui os resultados para uma superfície esférica de calibração e também para uma córnea in vivo com alto grau de astigmatismo, mostrando a curvatura e elevação. CONCLUSÃO: Acredita-se que esta nova técnica pode propiciar a melhoria de alguns processos, como por exemplo: adaptação de lentes de contato, algoritmos para ablações costumizadas para hipermetropia, entre outros.PURPOSE: To develop the instrumentation and software for wide-angle corneal topography using a Placido-based videokeratographer. The objective is to allow the measurement of a greater area of the cornea using a simple adaptation to the Placido mire. METHODS: Using the traditional Placido disc of a commercial corneal topographer, 9 LEDs (Light Emitting Diodes were installed on the conic mire so that the voluntary patient could gaze in different directions. For each direction Placido images were acquired and processed to form, using a sophisticated computer graphics algorithm, a tridimensional

  13. NUMERICAL SIMULATION OF FLOW CONTROL OF WIDE-ANGLE DIFFUSER IN CLOSED-CIRCUIT CONTINUOUS TRANSONIC WIND TUNNEL%连续式风洞大开角扩散段流动控制数值模拟

    Institute of Scientific and Technical Information of China (English)

    丛成华; 廖达雄; 陈吉明; 李红喆

    2013-01-01

    在连续式跨声速风洞中,大开角对抑制压缩机尾流扰动和提高换热器入口气流品质有重要作用,依靠设计经验和工程估算等传统风洞设计方法,无法对大开角扩散段流动控制进行有效设计.为增强大开角扩散段防分离能力,提高出口气流品质,降低损失,采用计算流体力学方法,结合适当的边界条件,对使用阻尼网进行整流的不同设计方案进行了模拟,从结果可以看到,阻尼网布置位置和开孔率对大开角段内和出口的流动状态有很大影响,第一层阻尼网应位于分离点之前,开孔率介于0.6-0.66,第二层阻尼网布置位置应靠近出口,开孔率介于0.56~0.66之间;最后对大开角段内的流动机理和压力恢复效率进行了探讨.研究结果表明:数值模拟能够得出较为合理的参数匹配,有效提高流场指标.%The wide-angle diffuser (WAD) plays a vital role to restrain compressor wake distortion and to improve the flow quality before the heat exchanger in a closed-circuit continuous transonic wind tunnel. There is no reasonable path to design an optimal WAD with screens based on the design method of a conventional wind tunnel, such as the previous design experience and engineering correlations technology. The computational fluid dynamics (CFD) with proper boundary conditions was used to compare the performance of different configurations for capacity of separation control, the improvement of the outlet flow quality and decrease of the pressure loss. The position and opening to the sectional area ratio of screens has an important effect on the flow regimes inside and outlet of WAD based on the details of numerical results. The first screen should be placed at just before the separation point, and the ratio of opening to sectional area is between 0.6 and 0.66. It is recommended that the second screen is near to the outlet of WAD using the porosity of 0.56-0.66. Flow behaviors in WAD, such as uniformity

  14. Observing the Sun with Coronado telescopes telescopes

    CERN Document Server

    Pugh, Philip

    2007-01-01

    The Sun provides amateur astronomers with one of the few opportunities for daytime astronomy. In order to see the major features of our nearest star, special telescopes that have a very narrow visible bandwidth are essential. The bandwidth has to be as narrow as 1 A- 10-10 m (1 Angstrom) and centred on the absorption line of neutral hydrogen. This makes many major features of the Suna (TM)s chromosphere visible to the observer. Such narrow-band "Fabry-Perot etalon filters" are high technology, and until the introduction of the Coronado range of solar telescopes, were too expensive for amateur use. The entry-level Coronado telescope, the PST (Personal Solar Telescope) costs under 500. Solar prominences (vast columns of plasma, best seen at the edge of the solar disk), filaments, flares, sunspots, plage and active regions are all visible and can be imaged to produce spectacular solar photographs. Philip Pugh has assembled a team of contributors who show just how much solar work can be done with Coronado telesco...

  15. Two Easily Made Astronomical Telescopes.

    Science.gov (United States)

    Hill, M.; Jacobs, D. J.

    1991-01-01

    The directions and diagrams for making a reflecting telescope and a refracting telescope are presented. These telescopes can be made by students out of plumbing parts and easily obtainable, inexpensive, optical components. (KR)

  16. The AMANDA neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Andres, E.C.; Askebjer, P.; Barwick, S.W.; Bay, R.C.; Bergstrom,L.; Biron, A.; Booth, J.; Botner, O.; Bouchta, A.; Carius, S.; Carlson,M.; Chinowsky, W.; Chirkin, D.; Conrad,J.; Costa, C.G.S.; Cowen, D.; Dalberg, E.; DeYoung, T.; Edsjo, J.; Ekstrom, P.; Goobar, A.; Gray, L.; Hallgren, A.; Halzen, F.; Hardtke, R.; Hart, S.; He, Y.; de, los, Heros,C.P.; Hill, G.; Hulth, PO.; Hundertmark, S.; Jacobsen, J.; Jones, A.; Kandhadai, V.; Karle, A.; Kim, J.; Leich, H.; Leuthold, M.; Lindahl, P.; Liubarsky, I.; Loaiza, P.; Lowder, D.; Marciniewski, P.; Miller, T.C.; Miocinovic, P.; Mock, P.C.; Morse, R.; Newcomer, M.; Niessen, P.; Nygren,D.; Porrata, R.; Potter, D.; Price, P.B.; Przybylski, G.; Rhode, W.; Richter, S.; Rodriguez, J.; Romenesko, P.; Ross, D.; Rubinstein, H.; Schmidt, T.; Schneider, E.; Schwarz, R.; Schwendicke, U.; Smoot, G.; Solarz, M.; Sorin, V.; Spiering, C.; Steffen, P.; Stokstad, R.; Streicher, O.; Taboada, I.; Thon, T.; Tilav, S.; Walck, C.; Wiebusch,C.H.; Wischnewski, R.; Woschnagg, K.; Wu, W.; Yodh, G.; Young, S.; AMANDACollaboration

    1999-04-01

    With an effective telescope area of order 10(4) m(2) for TeVneutrinos, a threshold near similar to 50 GeV and a pointing accuracy of2.5 degrees per muon track, the AMANDA detector represents the first of anew generation of high energy neutrino telescopes, reaching a scaleenvisaged over 25 years ago. We describe early results on the calibrationof natural deep ice as a particle detector as well as on AMANDA'sperformance as a neutrino telescope.

  17. The AMANDA neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Andres, E.C.; Askebjer, P.; Barwick, S.W.; Bay, R.C.; Bergstroem, L.; Biron, A.; Booth, J.; Botner, O.; Bouchta, A.; Carius, S.; Carlson, M.; Chinowsky, W.; Chirkin, D.; Conrad, J.; Costa, C.G.S.; Cowen, D.; Dalberg, E.; DeYoung, T.; Edsjoe, J.; Ekstroem, P.; Goobar, A.; Gray, L.; Hallgren, A.; Halzen, F.; Hardtke, R.; Hart, S.; He, Y.; Heros, C.P. de los; Hill, G.; Hulth, P.O.; Hundertmark, S.; Jacobsen, J.; Jones, A.; Kandhadai, V.; Karle, A.; Kim, J.; Leich, H.; Leuthold, M.; Lindahl, P.; Liubarsky, I.; Loaiza, P.; Lowder, D.; Marciniewski, P.; Miller, T.C.; Miocinovic, P.; Mock, P.C.; Morse, R.; Newcomer, M.; Niessen, P.; Nygren, D.; Porrata, R.; Potter, D.; Price, P.B.; Przybylski, G.; Rhode, W.; Richter, S.; Rodriquez, J.; Romenesko, P.; Ross, D.; Rubinstein, H.; Schmidt, T.; Schneider, E.; Schwartz, R.; Schwendicke, U.; Smoot, G.; Solarz, M.; Sorin, V.; Spiering, C.; Steffen, P.; Stokstad, R.; Streicher, O.; Taboada, I.; Thon, T.; Tilav, S.; Walck, C.; Wiebusch, C.H.; Wischnewski, R.; Woschnagg, K.; Wu, W.; Yodh, G.; Young, S

    1999-05-01

    With an effective telescope area of order 10{sup 4} m{sup 2} for TeV neutrinos, a threshold near {approx}50 GeV and a pointing accuracy of 2.5 degrees per muon track, the AMANDA detector represents the first of a new generation of high energy neutrino telescopes, reaching a scale envisaged over 25 years ago. We describe early results on the calibration of natural deep ice as a particle detector as well as on AMANDA's performance as a neutrino telescope.

  18. Modular assembled space telescope

    Science.gov (United States)

    Feinberg, Lee D.; Budinoff, Jason; MacEwen, Howard; Matthews, Gary; Postman, Marc

    2013-09-01

    We present a new approach to building a modular segmented space telescope that greatly leverages the heritage of the Hubble Space Telescope and the James Webb Space Telescope. The modular design in which mirror segments are assembled into identical panels allows for economies of scale and for efficient space assembly that make a 20-m aperture approach cost effective. This assembly approach can leverage NASA's future capabilities and has the power to excite the public's imagination. We discuss the science drivers, basic architecture, technology, and leveraged NASA infrastructure, concluding with a proposed plan for going forward.

  19. Goddard Robotic Telescope (GRT)

    Data.gov (United States)

    National Aeronautics and Space Administration — Since it is not possible to predict when a Gamma-Ray Burst (GRB) occurs, the follow-up ground telescopes must be distributed as uniform as possible all over the...

  20. Parabolic Strip Telescope

    CERN Document Server

    Chadzitaskos, Goce

    2013-01-01

    We present a proposal of a new type of telescopes using a rotating parabolic strip as the primary mirror. It is the most principal modification of the design of telescopes from the times of Galileo and Newton. In order to demonstrate the basic idea, the image of an artificial constellation observed by this kind of telescope was reconstructed using the techniques described in this article. As a working model of this new telescope, we have used an assembly of the primary mirror---a strip of acrylic glass parabolic mirror 40 cm long and 10 cm wid shaped as a parabolic cylinder of focal length 1 m---and an artificial constellation, a set of 5 apertures in a distance of 5 m illuminated from behind. In order to reconstruct the image, we made a series of snaps, each after a rotation of the constellation by 15 degrees. Using Matlab we reconstructed the image of the artificial constellation.

  1. The Dark Matter Telescope

    CERN Document Server

    Tyson, J A; Angel, J R P; Wittman, David

    2001-01-01

    Weak gravitational lensing enables direct reconstruction of dark matter maps over cosmologically significant volumes. This research is currently telescope-limited. The Dark Matter Telescope (DMT) is a proposed 8.4 m telescope with a 3 degree field of view, with an etendue of 260 $(m. degree)^2$, ten times greater than any other current or planned telescope. With its large etendue and dedicated observational mode, the DMT fills a nearly unexplored region of parameter space and enables projects that would take decades on current facilities. The DMT will be able to reach 10-sigma limiting magnitudes of 27-28 magnitude in the wavelength range .3 - 1 um over a 7 square degree field in 3 nights of dark time. Here we review its unique weak lensing cosmology capabilities and the design that enables those capabilities.

  2. Pupil Alignment Considerations for Large, Deployable Space Telescopes

    Science.gov (United States)

    Bos, Brent J.; Ohl, Raymond G.; Kubalak, Daivd A.

    2011-01-01

    For many optical systems the properties and alignment of the internal apertures and pupils are not critical or controlled with high precision during optical system design, fabrication or assembly. In wide angle imaging systems, for instance, the entrance pupil position and orientation is typically unconstrained and varies over the system s field of view in order to optimize image quality. Aperture tolerances usually do not receive the same amount of scrutiny as optical surface aberrations or throughput characteristics because performance degradation is typically graceful with misalignment, generally only causing a slight reduction in system sensitivity due to vignetting. But for a large deployable space-based observatory like the James Webb Space Telescope (JWST), we have found that pupil alignment is a key parameter. For in addition to vignetting, JWST pupil errors cause uncertainty in the wavefront sensing process that is used to construct the observatory on-orbit. Furthermore they also open stray light paths that degrade the science return from some of the telescope s instrument channels. In response to these consequences, we have developed several pupil measurement techniques for the cryogenic vacuum test where JWST science instrument pupil alignment is verified. These approaches use pupil alignment references within the JWST science instruments; pupil imaging lenses in three science instrument channels; and unique pupil characterization features in the optical test equipment. This will allow us to verify and crosscheck the lateral pupil alignment of the JWST science instruments to approximately 1-2% of their pupil diameters.

  3. The Mini-EUSO telescope on the ISS

    Science.gov (United States)

    Scotti, Valentina; Osteria, Giuseppe

    2017-02-01

    The Mini-EUSO project aims to perform observations of the UV-light night emission from Earth. The UV background produced in atmosphere is a key measurement for any experiment aiming at the observation of Extreme Energy Cosmic Rays (EECR) from space, the most energetic component of the cosmic radiation. The Mini-EUSO instrument will be placed within the International Space Station (ISS) in the Russian Module and measures through a UV transparent window. The instrument comprises a compact telescope with a large field of view, based on an optical system employing two Fresnel lenses for increased light collection. The light is focused onto an array of photo-multipliers and the resulting signal is converted into digital, processed and stored via the electronics subsystems on-board. The instrument is designed and built by the members of the JEM-EUSO collaboration. JEM-EUSO is a wide-angle refractive UV telescope being proposed for attachment to the ISS, which has been designed to address basic problems of fundamental physics and high-energy astrophysics investigating the nature of cosmic rays with energies above 1020 eV. Mini-EUSO will be able to study beside EECRs a wide range of scientific phenomena including atmospheric physics, strange quark matter and bioluminescence. The mission is approved by the Italian Space Agency and the Russian Space Agency. Scientific, technical and programmatic aspects of this project will be described.

  4. Large Binocular Telescope Project

    Science.gov (United States)

    Hill, John M.

    1997-03-01

    The large binocular telescope (LBT) project have evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 by 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson, Arizona. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train -- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in the fall of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximum flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximum stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1996 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson), EIE and ADS Italia

  5. Parallel readout of two-element CdZnTe detectors with real-time digital signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Shi Zhubin; Wang Linjun; Qin Kaifeng; Min Jiahua; Zhang Jijun; Liang Xiaoyan; Huang Jian; Tang Ke; Xia Yiben, E-mail: ljwang@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

    2010-12-15

    Readout electronics, especially digital electronics, for two-element CdZnTe (CZT) detectors in parallel are developed. The preliminary results show the detection efficiency of the two-element CZT detectors in parallel with analog electronics is as many as 1.8 and 2.1 times the single ones, and the energy resolution (FWHM) is limited by that of the single one by the means of analog electronics. However, the digital method for signal processing will be sufficiently better by contrast with an analog method especially in energy resolution. The energy resolution by the means of digital electronics can be improved by about 26.67%, compared to that only with analog electronics, while their detection efficiency is almost the same. The cause for this difference is also discussed. (semiconductor devices)

  6. SEMICONDUCTOR DEVICES Parallel readout of two-element CdZnTe detectors with real-time digital signal processing

    Science.gov (United States)

    Zhubin, Shi; Linjun, Wang; Kaifeng, Qin; Jiahua, Min; Jijun, Zhang; Xiaoyan, Liang; Jian, Huang; Ke, Tang; Yiben, Xia

    2010-12-01

    Readout electronics, especially digital electronics, for two-element CdZnTe (CZT) detectors in parallel are developed. The preliminary results show the detection efficiency of the two-element CZT detectors in parallel with analog electronics is as many as 1.8 and 2.1 times the single ones, and the energy resolution (FWHM) is limited by that of the single one by the means of analog electronics. However, the digital method for signal processing will be sufficiently better by contrast with an analog method especially in energy resolution. The energy resolution by the means of digital electronics can be improved by about 26.67%, compared to that only with analog electronics, while their detection efficiency is almost the same. The cause for this difference is also discussed.

  7. The Multiple-Mirror Telescope

    Science.gov (United States)

    Carleton, Nathaniel P.; Hoffmann, William F.

    1978-01-01

    Describes the basic design and principle of operating an optical-infrared telescope, the MMT. This third largest telescope in the world represents a new stage in telescope design; it uses a cluster of six reflecting telescopes, and relies on an automatic sensing and control system. (GA)

  8. Robotic and Survey Telescopes

    Science.gov (United States)

    Woźniak, Przemysław

    Robotic telescopes are revolutionizing the way astronomers collect their dataand conduct sky surveys. This chapter begins with a discussion of principles thatguide the process of designing, constructing, and operating telescopes andobservatories that offer a varying degree of automation, from instruments remotelycontrolled by observers to fully autonomous systems requiring no humansupervision during their normal operations. Emphasis is placed on designtrade-offs involved in building end-to-end systems intended for a wide range ofscience applications. The second part of the chapter contains descriptions ofseveral projects and instruments, both existing and currently under development.It is an attempt to provide a representative selection of actual systems thatillustrates state of the art in technology, as well as important ideas and milestonesin the development of the field. The list of presented instruments spans the fullrange in size starting from small all-sky monitors, through midrange robotic andsurvey telescopes, and finishing with large robotic instruments and surveys.Explosive growth of telescope networking is enabling entirely new modesof interaction between the survey and follow-up observing. Increasingimportance of standardized communication protocols and software is stressed.These developments are driven by the fusion of robotic telescope hardware,massive storage and databases, real-time knowledge extraction, and datacross-correlation on a global scale. The chapter concludes with examplesof major science results enabled by these new technologies and futureprospects.

  9. The South Pole Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, J.E.; Ade, P.A.R.; Carlstrom, J.E.; Cho, H.M.; Crawford,T.; Dobbs, M.; Greer, C.H.; Halverson, N.W.; Holzapfel, W.L.; Lanting,T.M.; Lee, A.T.; Leitch, E.M.; Leong, J.; Lu, W.; Lueker, M.; Mehl, J.; Meyer, S.S.; Mohr, J.J.; Padin, S.; Plagge, T.; Pryke, C.; Runyan, M.C.; Schwan, D.; Sharp, M.K.; Spieler, H.; Staniszewski, Z.; Stark, A.A.

    2004-11-04

    A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10 m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency-multiplexed readouts. The first key project will be to conduct a survey over 4000 degrees for galaxy clusters using the Sunyaev-Zeldovich Effect. This survey should find many thousands of clusters with a mass selection criteria that is remarkably uniform with redshift. Armed with redshifts obtained from optical and infrared follow-up observations, it is expected that the survey will enable significant constraints to be placed on the equation of state of the dark energy.

  10. The Travelling Telescope

    Science.gov (United States)

    Murabona Oduori, Susan

    2015-08-01

    The telescope has been around for more than 400 years, and through good use of it scientists have made many astonishing discoveries and begun to understand our place in the universe. Most people, however, have never looked through one. Yet it is a great tool for cool science and observation especially in a continent and country with beautifully dark skies. The Travelling Telescope project aims to invite people outside under the stars to learn about those curious lights in the sky.The Travelling Telescope aims to promote science learning to a wide range of Kenyan schools in various locations exchanging knowledge about the sky through direct observations of celestial bodies using state of the art telescopes. In addition to direct observing we also teach science using various hands-on activities and astronomy software, ideal for explaining concepts which are hard to understand, and for a better grasp of the sights visible through the telescope. We are dedicated to promoting science using astronomy especially in schools, targeting children from as young as 3 years to the youth, teachers, their parents and members of the public. Our presentation focuses on the OAD funded project in rural coastal Kenya.

  11. The South Pole Telescope

    CERN Document Server

    Ruhl, J E; Carlstrom, J E; Cho, H M; Crawford, T; Dobbs, M; Greer, C H; Halverson, W; Holzapfel, W L; Lanting, T M; Lee, A T; Leong, J; Leitch, E M; Lu, W; Lueker, M; Mehl, J; Meyer, S S; Mohr, J J; Padin, S; Plagge, T; Pryke, C L; Schwan, D; Sharp, M K; Runyan, M C; Spieler, H; Staniszewski, Z; Stark, A A

    2004-01-01

    A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency...

  12. LSST telescope modeling overview

    Science.gov (United States)

    Sebag, J.; Andrew, J.; Angeli, G.; Araujo, C.; Barr, J.; Callahan, S.; Cho, M.; Claver, C.; Daruich, F.; Gressler, W.; Hileman, E.; Liang, M.; Muller, G.; Neill, D.; Schoening, W.; Warner, M.; Wiecha, O.; Xin, B.; Orden Martinez, Alfredo; Perezagua Aguado, Manuel; García Marchena, Luis; Ruiz de Argandoña, Ismael

    2016-08-01

    During this early stage of construction of the Large Synoptic Survey Telescope (LSST), modeling has become a crucial system engineering process to ensure that the final detailed design of all the sub-systems that compose the telescope meet requirements and interfaces. Modeling includes multiple tools and types of analyses that are performed to address specific technical issues. Three-dimensional (3D) Computeraided Design (CAD) modeling has become central for controlling interfaces between subsystems and identifying potential interferences. The LSST Telescope dynamic requirements are challenging because of the nature of the LSST survey which requires a high cadence of rapid slews and short settling times. The combination of finite element methods (FEM), coupled with control system dynamic analysis, provides a method to validate these specifications. An overview of these modeling activities is reported in this paper including specific cases that illustrate its impact.

  13. Telescopes and Techniques

    CERN Document Server

    Kitchin, C R

    2013-01-01

    Telescopes and Techniques has proved itself in its first two editions, having become probably one of the most widely used astronomy texts, both for amateur astronomers and astronomy and astrophysics undergraduates. Both earlier editions of the book were widely used for introductory practical astronomy courses in many universities. In this Third Edition the author guides the reader through the mathematics, physics and practical techniques needed to use today's telescopes (from the smaller models to the larger instruments installed in many colleges) and how to find objects in the sky. Most of the physics and engineering involved is described fully and requires little prior knowledge or experience. Both visual and electronic imaging techniques are covered, together with an introduction to how data (measurements) should be processed and analyzed. A simple introduction to radio telescopes is also included. Brief coverage of the more advanced topics of photometry and spectroscopy are included, but mainly to enable ...

  14. Integrated Modeling of Telescopes

    CERN Document Server

    Andersen, Torben

    2011-01-01

    With increasingly complex and costly opto-mechanical systems, there is a growing need for reliable computer modeling and simulation. The field of integrated modeling, combining optics, mechanics, control engineering, and other disciplines, is the subject of this book. Although the book primarily focuses on ground-based optical telescopes, the techniques introduced are applicable also to other wavelengths and to other opto-mechanical applications on the ground or in space. Basic tools of integrated modeling are introduced together with concepts of ground-based telescopes. Modeling of optical systems, structures, wavefront control systems with emphasis on segmented mirror control, and active and adaptive optics are described together with a variety of noise sources; many examples are included in this book. Integrated Modeling of Telescopes is a text for physicists and engineers working in the field of opto-mechanical design and wavefront control, but it will also be valuable as a textbook for PhD students.

  15. The Discovery Channel Telescope

    Science.gov (United States)

    Millis, R. L.; Dunham, E. W.; Sebring, T. A.; Smith, B. W.; de Kock, M.; Wiecha, O.

    2004-11-01

    The Discovery Channel Telescope (DCT) is a 4.2-m telescope to be built at a new site near Happy Jack, Arizona. The DCT features a large prime focus mosaic CCD camera with a 2-degree-diameter field of view especially designed for surveys of KBOs, Centaurs, NEAs and other moving or time-variable targets. The telescope can be switched quickly to a Ritchey-Chretien configuration for optical/IR spectroscopy or near-IR imaging. This flexibility allows timely follow-up physical studies of high priority objects discovered in survey mode. The ULE (ultra-low-expansion) meniscus primary and secondary mirror blanks for the telescope are currently in fabrication by Corning Glass. Goodrich Aerospace, Vertex RSI, M3 Engineering and Technology Corp., and e2v Technologies have recently completed in-depth conceptual design studies of the optics, mount, enclosure, and mosaic focal plane, respectively. The results of these studies were subjected to a formal design review in July, 2004. Site testing at the 7760-ft altitude Happy Jack site began in 2001. Differential image motion observations from 117 nights since January 1, 2003 gave median seeing of 0.84 arcsec FWHM, and the average of the first quartile was 0.62 arcsec. The National Environmental Policy Act (NEPA) process for securing long-term access to this site on the Coconino National Forest is nearing completion and ground breaking is expected in the spring of 2005. The Discovery Channel Telescope is a project of the Lowell Observatory with major financial support from Discovery Communications, Inc. (DCI). DCI plans ongoing television programming featuring the construction of the telescope and the research ultimately undertaken with the DCT. An additional partner can be accommodated in the project. Interested parties should contact the lead author.

  16. Pointing the SOFIA Telescope

    CERN Document Server

    Gross, Michael A K; Moore, Elizabeth M

    2010-01-01

    SOFIA is an airborne, gyroscopically stabilized 2.5m infrared telescope, mounted to a spherical bearing. Unlike its predecessors, SOFIA will work in absolute coordinates, despite its continually changing position and attitude. In order to manage this, SOFIA must relate equatorial and telescope coordinates using a combination of avionics data and star identification, manage field rotation and track sky images. We describe the algorithms and systems required to acquire and maintain the equatorial reference frame, relate it to tracking imagers and the science instrument, set up the oscillating secondary mirror, and aggregate pointings into relocatable nods and dithers.

  17. Reflecting telescope optics

    CERN Document Server

    Wilson, Raymond N

    2004-01-01

    R.N. Wilson's two-volume treatise on reflecting telescope optics has become a classic in its own right. It is intended to give a complete treatment of the subject, addressing professionals in research and industry as well as students of astronomy and amateur astronomers. This first volume, Basic Design Theory and its Historical Development, is devoted to the theory of reflecting telescope optics and systematically recounts the historical progress. The author's approach is morphological, with strong emphasis on the historical development. The book is richly illustrated including spot-diagrams a

  18. New Vacuum Solar Telescope

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    With its pure aperture up to 985mm, the New Vacuum Solar Telescope of China (NVST) has become the world's biggest vacuum solar telescope. The main science task of NVST is the high-resolution observation of photosphere and chromosphere including their fine structure of magnetic field on the sun. The NVST was equipped with many new technologies and powerful instruments, such as an adaptive optical system, a polarization analyzer, two vertical spectrographs, a high-resolution image system and a very narrow Ha filter (0.125A).

  19. THE LARGE MILLIMETER TELESCOPE

    Directory of Open Access Journals (Sweden)

    D. H. Hughes

    2009-01-01

    Full Text Available This paper, presented on behalf of the Large Millimeter Telescope (LMT project team, describes the status and near-term plans for the telescope and its initial instrumentation. The LMT is a bi-national collaboration between M xico and the USA, led by the Instituto Nacional de Astrof sica, ptica y Electr nica (INAOE and the University of Massachusetts at Amherst, to construct, commission and operate a 50 m diameter millimeterwave radio telescope. Construction activities are nearly complete at the LMT site, at an altitude of 4600 m on the summit of Sierra Negra, an extinct volcano in the Mexican state of Puebla. Full movement of the telescope, under computer control in both azimuth and elevation, has been achieved. First-light at centimeter wavelengths on astronomical sources was obtained in November 2006. Installation of precision surface segments for millimeter-wave operation is underway, with the inner 32 m diameter of the surface now complete and ready to be used to obtain rst-light at millimeter wavelengths in 2008. Installation of the remainder of the re ector will continue during the next year and be completed in 2009 for nal commissioning of the antenna. The full LMT antenna, out ted with its initial complement of scienti c instruments, will be a world-leading scienti c research facility for millimeter-wave astronomy.

  20. A Simple "Tubeless" Telescope

    Science.gov (United States)

    Straulino, S.; Bonechi, L.

    2010-01-01

    Two lenses make it possible to create a simple telescope with quite large magnification. The set-up is very simple and can be reproduced in schools, provided the laboratory has a range of lenses with different focal lengths. In this article, the authors adopt the Keplerian configuration, which is composed of two converging lenses. This instrument,…

  1. Exploring Galileo's Telescope

    Science.gov (United States)

    Straulino, Samuele; Terzuoli, Alessandra

    2010-01-01

    In the first months of 2009, the International Year of Astronomy, the authors developed an educational project for middle-level students connected with the first astronomical discoveries that Galileo Galilei (1564-1642) made 400 years ago. The project included the construction of a basic telescope and the observation of the Moon. The project, if…

  2. NRAO Green Bank Telescope (GBT)

    Data.gov (United States)

    Federal Laboratory Consortium — The largest fully steerable telescope in the world - the Robert C. Byrd Green Bank Telescope, began observations in Green Bank, West Virginia in 2000and is a wonder...

  3. Optical Space Telescope Assembly Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Space Telescope Assembly (OSTA) task is to demonstrate the technology readiness of assembling large space telescopes on orbit in 2015. This task is an...

  4. Telescope Spectrophotometric and Absolute Flux Calibration, and National Security Applications, Using a Tunable Laser on a Satellite

    CERN Document Server

    Albert, J; Rhodes, J; Albert, Justin; Burgett, William; Rhodes, Jason

    2006-01-01

    We propose a tunable laser-based satellite-mounted spectrophotometric and absolute flux calibration system, to be utilized by ground- and space-based telescopes. As uncertainties on the photometry, due to imperfect knowledge of both telescope optics and the atmosphere, will in the near future begin to dominate the uncertainties on fundamental cosmological parameters such as Omega_Lambda and w in measurements from SNIa, weak gravitational lensing, and baryon oscillations, a method for reducing such uncertainties is needed. We propose to improve spectrophotometric calibration, currently obtained using standard stars, by placing a tunable laser and a wide-angle light source on a satellite by early next decade (perhaps included in the upgrade to the GPS satellite network) to improve absolute flux calibration to 0.1% and relative spectrophotometric calibration to better than 0.001% across the visible and near-infrared spectrum. As well as fundamental astrophysical applications, the system proposed here potentially...

  5. Progress in Space Solar Telescope

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper we will summarize the progress in the development of the Chinese Space Solar Telescope (SST) during the past few years. The main scientific objective of SST is to observe the fundamental structure of solar magnetic field with its 1-m optical telescope. The success of 1-m Swedish Solar Telescope and Hinode underscores the importance of this 1-m space telescope. In addition, some key technical problems have been solved.

  6. Uzaybimer Radio Telescope Control System

    Science.gov (United States)

    Balbay, R.; Öz, G. K.; Arslan, Ö.; Özeren, F. F.; Küçük, İ.

    2016-12-01

    A 13 meters former NATO radar is being converted into a radio telescope. The radio telescope is controlled by a system which has been developed at UZAYBİMER. The Telescope Control System(TCS) has been designed using modern industrial systems. TCS has been developed in LabView platform in which works Windows embedded OS. The position feedback used on radio telescopes is an industrial EtherCAT standard. ASCOM library is used for astronomical calculations.

  7. Comparing NEO Search Telescopes

    CERN Document Server

    Myhrvold, Nathan

    2015-01-01

    Multiple terrestrial and space-based telescopes have been proposed for detecting and tracking near-Earth objects (NEOs). Detailed simulations of the search performance of these systems have used complex computer codes that are not widely available, which hinders accurate cross- comparison of the proposals and obscures whether they have consistent assumptions. Moreover, some proposed instruments would survey infrared (IR) bands, whereas others would operate in the visible band, and differences among asteroid thermal and visible light models used in the simulations further complicate like-to-like comparisons. I use simple physical principles to estimate basic performance metrics for the ground-based Large Synoptic Survey Telescope and three space-based instruments - Sentinel, NEOCam, and a Cubesat constellation. The performance is measured against two different NEO distributions, the Bottke et al. distribution of general NEOs, and the Veres et al. distribution of earth impacting NEO. The results of the comparis...

  8. The ANTARES Neutrino Telescope

    CERN Document Server

    Perrina, Chiara

    2015-01-01

    At about 40 km off the coast of Toulon (France), anchored at 2475 m deep in the Mediterranean Sea, there is ANTARES: the first undersea neutrino telescope and the only one currently operating. The detector consists of 885 photomultiplier tubes arranged into 12 strings of 450-metres high, with the aim to detect the Cherenkov light induced by the charged superluminal interaction products of neutrinos. Its main scientific target is the search for high-energy (TeV and beyond) neutrinos from cosmic accelerators, as predicted by hadronic interaction models, and the measurement of the cosmic neutrino diffuse flux, focusing in particular on events coming from below the horizon (up-going events) in order to significantly reduce the atmospheric muons background. Thanks to the development of a strategy for the identification of neutrinos coming from above the horizon (down-going events) the field of view of the telescope will be extended.

  9. Telescopic limiting magnitudes

    Science.gov (United States)

    Schaefer, Bradley E.

    1990-01-01

    The prediction of the magnitude of the faintest star visible through a telescope by a visual observer is a difficult problem in physiology. Many prediction formulas have been advanced over the years, but most do not even consider the magnification used. Here, the prediction algorithm problem is attacked with two complimentary approaches: (1) First, a theoretical algorithm was developed based on physiological data for the sensitivity of the eye. This algorithm also accounts for the transmission of the atmosphere and the telescope, the brightness of the sky, the color of the star, the age of the observer, the aperture, and the magnification. (2) Second, 314 observed values for the limiting magnitude were collected as a test of the formula. It is found that the formula does accurately predict the average observed limiting magnitudes under all conditions.

  10. Everyday Radio Telescope

    CERN Document Server

    Mandal, Pranshu; Kumar, Pratik; Yelikar, Anjali; Soni, Kanchan; T, Vineeth Krishna

    2016-01-01

    We have developed an affordable, portable college level radio telescope for amateur radio astronomy which can be used to provide hands-on experience with the fundamentals of a radio telescope and an insight into the realm of radio astronomy. With our set-up one can measure brightness temperature and flux of the Sun at 11.2 GHz and calculate the beam width of the antenna. The set-up uses commercially available satellite television receiving system and parabolic dish antenna. We report the detection of point sources like Saturn and extended sources like the galactic arm of the Milky way. We have also developed python pipeline, which are available for free download, for data acquisition and visualization.

  11. Origins Space Telescope

    Science.gov (United States)

    Cooray, Asantha R.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its spectrographs will enable 3D surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu. I will summarize the OST STDT, mission design and instruments, key science drivers, and the study plan over the next two years.

  12. The Cherenkov Telescope Array

    Science.gov (United States)

    Connaughton, Valerie

    2014-03-01

    The Cherenkov Telescope Array (CTA) is a large collaborative effort dedicated to the design and operation of the next-generation ground-based very high-energy gamma-ray observatory. CTA will improve by about one order of magnitude the sensitivity with respect to the current major arrays (VERITAS, H.E.S.S., and MAGIC) in the core energy range of 100 GeV to 10 TeV, and will extend the viability of the imaging atmospheric Cherenkov technique (IACT) down to tens of GeV and above 100 TeV. In order to achieve such improved performance at both a northern and southern CTA site, four 23m diameter Large Size Telescopes (LST) optimized for low energy gamma rays will be deployed close to the centre of the array. A larger number of Medium Size Telescopes (MST) will be optimized for the core IACT energy range. The southern site will include 25 12m single-mirror MSTs and a US contribution of up to 24 novel dual-mirror design Schwarzschild-Couder (SC) type MSTs with a primary mirror of 9.5m diameter, and will also include an array of Small Size Telescopes (SST) to observe the highest-energy gamma rays from galactic sources. The SSTs can be smaller and more widely separated because more energetic gamma rays produce a larger Cherenkov light pool with many photons. The SSTs achieve a large collection area by covering a wide (10 sq km) footprint on the ground. The CTA project is finishing its preparatory phase, and the pre-production phase will start this year. I will review the status and the expected performance of CTA as well as the main scientific goals for the observatory.

  13. [Galileo and his telescope].

    Science.gov (United States)

    Strebel, Christoph

    2006-01-01

    Galileo's publication of observations made with his newly reinvented telescope provoked a fierce debate. In April 1610 Martinus Horky, a young Bohemian astronomer, had an opportunity to make his own observations with Galileo's telescope in the presence of Antonio Magini and other astronomers. Horky and the other witnesses denied the adequacy of Galileo's telescope and therefore the bona fides of his discoveries. Kepler conjectured Horky as well as all his witnesses to be myopic. But Kepler's objection could not stop the publication of Horky's Peregrinatio contra nuncium sidereum (Modena, 1610), the first printed refutation of Galileo's Sidereus nuncius. In his treatise, Horky adresses four questions: 1) Do the four newly observed heavenly bodies actually exist? Horky denies their existence on various grounds: a) God, as every astronomer teaches, has created only seven moveable heavenly bodies and astronomical knowledge originates in God, too. b) Heavenly bodies are either stars or planets. Galileo's moveable heavenly bodies fit into neither category. c) If they do exist, why have they not already been observed by other scholars? Horky concludes that there are no such heavenly bodies. 2) What are these phenomena? They are purely artefactual, and produced by Galileo's telescope. 3) How are they like? Galileo's "stars" are so small as to be almost invisible. Galileo claims that he has measured their distances from each other. This however is impossible due to their diminutive size and other observational problems. Hence, Galileo's claim is a further proof that he is a fraud. 4) Why are they? For Galileo they are a chance to earn money but for astronomers like Horky they are a reason to offer thanks and honour to God. Horky's treatise was favourably received by the enemies of Galileo. But Kepler's critique was devastating. After calling on Kepler in Prague, Horky had to revoke the contents of his book.

  14. Fast Fourier transform telescope

    Science.gov (United States)

    Tegmark, Max; Zaldarriaga, Matias

    2009-04-01

    We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore’s law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog⁡2N rather than N2) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.

  15. Hubble Space Telescope satellite

    Science.gov (United States)

    Mitchell, R. E.

    1985-01-01

    The Hubble Space Telescope, named for the American astronomer Edwin Powell Hubble, will be the largest and most powerful astronomical instrument ever orbited. Placed above the obscuring effects of the earth's atmosphere in a 600-km orbit, this remotely-controlled, free-flying satellite observatory will expand the terrestrial-equivalent resolution of the universe by a factor of seven, or a volumetric factor of 350. This telescope has a 2.4-m primary mirror and can accommodate five scientific instruments (cameras, spectrographs and photometers). The optics are suitable for a spectral range from 1100 angstrom to 1 mm wavelength. With a projected service life of fifteen years, the spacecraft can be serviced on-orbit for replacement of degraded systems, to insert advanced scientific instruments, and to reboost the telescope from decayed altitudes. The anticipated image quality will be a result of extremely precise lambda/20 optics, stringent cleanliness, and very stable pointing: jitter will be held to less than 0.01 arcsecond for indefinite observation periods, consistent with instrument apertures as small as 0.1 arcsecond.

  16. SOAR Telescope Progress Report

    Science.gov (United States)

    Sebring, T.; Cecil, G.; Krabbendam, V.

    1999-12-01

    The 4.3m SOAR telescope is fully funded and under construction. A partnership between the country of Brazil, NOAO, Michigan State University, and the University of North Carolina at Chapel Hill, SOAR is being designed for high-quality imaging and imaging spectroscopy in the optical and near-IR over a field of view up to 12' diameter. US astronomers outside MSU and UNC will access 30% of the observing time through the standard NOAO TAC process. The telescope is being designed to support remote and synoptic observations. First light is scheduled for July 2002 at Cerro Pachon in Chile, a site with median seeing of 2/3" at 500 nm. The telescope will be operated by CTIO. Corning Inc. has fused the mirror blanks from boules of ULE glass. RSI in Richardson, Texas and Raytheon Optical Systems Inc. in Danbury, Conn. are designing and will fabricate the mount and active optics systems, respectively. The mount supports an instrument payload in excess of 5000 kg, at 2 Nasmyth locations and 3 bent Cass. ports. The mount and facility building have space for a laser to generate an artificial AO guide star. LabVIEW running under the Linux OS on compactPCI hardware has been adopted to control all telescope, detector, and instrument systems. The primary mirror is 10 cm thick and will be mounted on 120 electro-mechanical actuators to maintain its ideal optical figure at all elevations. The position of the light-weighted secondary mirror is adjusted to maintain collimation through use of a Shack-Hartmann wavefront sensor. The tertiary mirror feeds instruments and also jitters at up to 50 Hz to compensate for telescope shake and atmosphere wavefront tilt. The dome is a steel framework, with fiberglass panels. Air in the observing volume will be exchanged with that outside every few minutes by using large fans under computer control. All systems will be assembled and checked at the manufacturer's facility, then shipped to Chile. A short integration period is planned, and limited science

  17. The Planck Telescope reflectors

    Science.gov (United States)

    Stute, Thomas

    2004-09-01

    The mechanical division of EADS-Astrium GmbH, Friedrichshafen is currently engaged with the development, manufacturing and testing of the advanced dimensionally stable composite reflectors for the ESA satellite borne telescope Planck. The objective of the ESA mission Planck is to analyse the first light that filled the universe, the cosmic microwave background radiation. Under contract of the Danish Space Research Institute and ESA EADS-Astrium GmbH is developing the all CFRP primary and secondary reflectors for the 1.5-metre telescope which is the main instrument of the Planck satellite. The operational frequency ranges from to 25 GHz to 1000 GHz. The demanding high contour accuracy and surface roughness requirements are met. The design provides the extreme dimensional stability required by the cryogenic operational environment at around 40 K. The elliptical off-axis reflectors display a classical lightweight sandwich design with CFRP core and facesheets. Isostatic mounts provide the interfaces to the telescope structure. Protected VDA provides the reflecting surface. The manufacturing is performed at the Friedrichshafen premises of EADS-Space Transportation GmbH, the former Dornier composite workshops. Advanced manufacturing technologies like true angle lay-up by CNC fibre placement and filament winding are utilized. The protected coating is applied at the CAHA facilities at the Calar Alto Observatory, Spain. The exhaustive environmental testing is performed at the facilities of IABG, Munich (mechanical testing) and for the cryo-optical tests at CSL Liege. The project is in advanced state with both Qualification Models being under environmental testing. The flight models will be delivered in 2004. The paper gives an overview over the requirements and the main structural features how these requirements are met. Special production aspects and available test results are reported.

  18. The Cherenkov Telescope Array

    CERN Document Server

    Bigongiari, Ciro

    2016-01-01

    The Cherenkov Telescope Array (CTA) is planned to be the next generation ground based observatory for very high energy (VHE) gamma-ray astronomy. Gamma-rays provide a powerful insight into the non-thermal universe and hopefully a unique probe for new physics. Imaging Cherenkov telescopes have already discovered more than 170 VHE gamma-ray emitters providing plentiful of valuable data and clearly demonstrating the power of this technique. In spite of the impressive results there are indications that the known sources represent only the tip of the iceberg. A major step in sensitivity is needed to increase the number of detected sources, observe short time-scale variability and improve morphological studies of extended sources. An extended energy coverage is advisable to observe far-away extragalactic objects and improve spectral analysis. CTA aims to increase the sensitivity by an order of magnitude compared to current facilities, to extend the accessible gamma-ray energies from a few tens of GeV to a hundred o...

  19. Large Size Telescope Report

    CERN Document Server

    Mazin, D; Teshima, M

    2016-01-01

    The Cherenkov Telescope Array (CTA) observatory will be deployed over two sites in the two hemispheres. Both sites will be equipped with four Large Size Telescopes (LSTs), which are crucial to achieve the science goals of CTA in the 20-200 GeV energy range. Each LST is equipped with a primary tessellated mirror dish of 23 m diameter, supported by a structure made mainly of carbon fibre reinforced plastic tubes and aluminum joints. This solution guarantees light weight (around 100 tons), essential for fast repositioning to any position in the sky in <20 seconds. The camera is composed of 1855 photomultiplier tubes and embeds the control, readout and trigger electronics. The detailed design is now complete and production of the first LST, which will serve as a prototype for the remaining seven, is ongoing. The installation of the first LST at the Roque de los Muchachos Observatory on the Canary island of La Palma (Spain) started in July 2016. In this paper we will outline the technical solutions adopted to f...

  20. Magellan Telescopes operations 2008

    Science.gov (United States)

    Osip, David J.; Phillips, Mark M.; Palunas, Povilas; Perez, Frank; Leroy, M.

    2008-07-01

    The twin 6.5m Magellan Telescopes have been in routine operations at the Las Campanas Observatory in the Chilean Andes since 2001 and 2002 respectively. The telescopes are owned and operated by Carnegie for the benefit of the Magellan consortium members (Carnegie Institution of Washington, Harvard University, the University of Arizona, Massachusetts Institute of Technology, and the University of Michigan). This paper provides an up to date review of the scientific, technical, and administrative structure of the 'Magellan Model' for observatory operations. With a modest operations budget and a reasonably small staff, the observatory is operated in the "classical" mode, wherein the visiting observer is a key member of the operations team. Under this model, all instrumentation is supplied entirely by the consortium members and the various instrument teams continue to play a critical support role beyond initial deployment and commissioning activities. Here, we present a critical analysis of the Magellan operations model and suggest lessons learned and changes implemented as we continue to evolve an organizational structure that can efficiently deliver a high scientific return for the investment of the partners.

  1. Large size telescope report

    Science.gov (United States)

    Mazin, D.; Cortina, J.; Teshima, M.

    2017-01-01

    The Cherenkov Telescope Array (CTA) observatory will be deployed over two sites in the two hemispheres. Both sites will be equipped with four Large Size Telescopes (LSTs), which are crucial to achieve the science goals of CTA in the 20-200 GeV energy range. Each LST is equipped with a primary tessellated mirror dish of 23 m diameter, supported by a structure made mainly of carbon fibre reinforced plastic tubes and aluminum joints. This solution guarantees light weight (around 100 tons), essential for fast repositioning to any position in the sky in <20 seconds. The camera is composed of 1855 photomultiplier tubes and embeds the control, readout and trigger electronics. The detailed design is now complete and production of the first LST, which will serve as a prototype for the remaining seven, is ongoing. The installation of the first LST at the Roque de los Muchachos Observatory on the Canary island of La Palma (Spain) started in July 2016. In this paper we will outline the technical solutions adopted to fulfill the design requirements, present results of element prototyping and describe the installation and operation plans.

  2. Deep space telescopes

    CERN Document Server

    CERN. Geneva

    2006-01-01

    The short series of seminars will address results and aims of current and future space astrophysics as the cultural framework for the development of deep space telescopes. It will then present such new tools, as they are currently available to, or imagined by, the scientific community, in the context of the science plans of ESA and of all major world space agencies. Ground-based astronomy, in the 400 years since Galileo’s telescope, has given us a profound phenomenological comprehension of our Universe, but has traditionally been limited to the narrow band(s) to which our terrestrial atmosphere is transparent. Celestial objects, however, do not care about our limitations, and distribute most of the information about their physics throughout the complete electromagnetic spectrum. Such information is there for the taking, from millimiter wavelengths to gamma rays. Forty years astronomy from space, covering now most of the e.m. spectrum, have thus given us a better understanding of our physical Universe then t...

  3. Upgrade of the MAGIC telescopes

    CERN Document Server

    Mazin, Daniel; Garczarczyk, Markus; Giavitto, Gianluca; Sitarek, Julian

    2014-01-01

    The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs) located on the Canary island of La Palma. With 17m diameter mirror dishes and ultra-fast electronics, they provide an energy threshold as low as 50 GeV for observations at low zenith angles. The first MAGIC telescope was taken in operation in 2004 whereas the second one joined in 2009. In 2011 we started a major upgrade program to improve and to unify the stereoscopic system of the two similar but at that time different telescopes. Here we report on the upgrade of the readout electronics and digital trigger of the two telescopes, the upgrade of the camera of the MAGIC I telescope as well as the commissioning of the system after this major upgrade.

  4. Grid Integration of Robotic Telescopes

    CERN Document Server

    Breitling, F; Enke, H

    2008-01-01

    Robotic telescopes and grid technology have made significant progress in recent years. Both innovations offer important advantages over conventional technologies, particularly in combination with one another. Here, we introduce robotic telescopes used by the Astrophysical Institute Potsdam as ideal instruments for building a robotic telescope network. We also discuss the grid architecture and protocols facilitating the network integration that is being developed by the German AstroGrid-D project. Finally, we present three user interfaces employed for this purpose.

  5. Near Earth Object Survey Telescope

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Near Earth Object Survey Telescope (NEOST), located at the Xuyi station of the Purple Mountain Observatory, is a telescope with the most powerful detection capacity, the highest efficiency and the best performance in the fields of near Earth object survey and optical imaging in China. NEOST is an 171.8 Schmidt type telescope with a 1.20 meter primary mirror and a 1.04 meter corrector,

  6. Viewing Performance Appraisal with a Wide Angle Lens.

    Science.gov (United States)

    DeVries, David L.

    The majority of empirical studies on performance appraisal (PA) systems focus on the search for the perfect form in which subjective traits are replaced by objective and job-relevant, measurable behaviors. Organizations using a PA system to evaluate their employees struggle with issues of implementation, adaptation, and linkage with other human…

  7. Graphene-based extremely wide-angle tunable metamaterial absorber

    Science.gov (United States)

    Linder, Jacob; Halterman, Klaus

    2016-01-01

    We investigate the absorption properties of graphene-based anisotropic metamaterial structures where the metamaterial layer possesses an electromagnetic response corresponding to a near-zero permittivity. We find that through analytical and numerical studies, near perfect absorption arises over an unusually broad range of beam incidence angles. Due to the presence of graphene, the absorption is tunable via a gate voltage, providing dynamic control of the energy transmission. We show that this strongly enhanced absorption arises due to a coupling between light and a fast wave-mode propagating along the graphene/metamaterial hybrid. PMID:27554137

  8. Wide-angle chromatic aberration corrector for the human eye.

    Science.gov (United States)

    Benny, Yael; Manzanera, Silvestre; Prieto, Pedro M; Ribak, Erez N; Artal, Pablo

    2007-06-01

    The human eye is affected by large chromatic aberration. This may limit vision and makes it difficult to see fine retinal details in ophthalmoscopy. We designed and built a two-triplet system for correcting the average longitudinal chromatic aberration of the eye while keeping a reasonably wide field of view. Measurements in real eyes were conducted to examine the level and optical quality of the correction. We also performed some tests to evaluate the effect of the corrector on visual performance.

  9. Cluster Evolution in the Wide Angle ROSAT Pointed Survey (WARPS)

    CERN Document Server

    Schärf, C A; Perlman, E S; Ebeling, H; Wegner, G; Malkan, M A; Horner, D

    1998-01-01

    A new flux limited catalogue of low luminosity (Lx 0.3). The results are consistent with an unevolving population which does not exhibit the evolution seen in the higher luminosity cluster population. These observations can be qualitatively described by self-similarly evolving dark matter and preheated IGM models of X-ray cluster gas, with a power law index for the spectrum of matter density fluctuations n >= -1.

  10. Graphene-based extremely wide-angle tunable metamaterial absorber

    CERN Document Server

    Linder, Jacob

    2016-01-01

    We investigate the absorption properties of graphene-based anisotropic metamaterial structures where the metamaterial layer possesses an electromagnetic response corresponding to a near-zero permittivity. We find that through analytical and numerical studies, near perfect absorption arises over an unusually broad range of beam incidence angles. Due to the presence of graphene, the absorption is tunable via a gate voltage, providing dynamic control of the energy transmission. We show that this strongly enhanced absorption arises due to a coupling between light and a fast wave-mode propagating along the graphene/metamaterial hybrid.

  11. Wide-angle cornea-sclera (OCULAR) topography

    Science.gov (United States)

    Klein, Stanley A.; Corzine, John; Corbin, Jacob A.; Wechsler, Sheldon; Carney, Thom

    2002-06-01

    Most corneal topographers are slope-based instruments, measuring corneal slope based on light reflected by the cornea acting as a mirror. This mirror method limits corneal coverage to about 9 mm diameter. Both refractive surgery and contact lens fitting actually require a larger coverage than is obtainable using slope-based instruments. Height-based instruments should be able to measure a cornea/sclera area that is twice the size (four times the area) of slope-based topographers with an accuracy of a few microns. We have been testing a prototype of a new model height-based topographer manufactured by Euclid Systems. We find that single shots can produce a corneal coverage of up to 16 mm vertical and 20 mm horizontal. The heights and slopes in the corneal region have good replicability. Although the scleral region is noisier, it is the only topographer available able to measure scleral topography that is critically important to contact lens fitting. There are a number of improvements to the Euclid software and hardware that would enable it to fill an important niche in eye care and eye research.

  12. Role of platelets in neuroinflammation: a wide-angle perspective

    Directory of Open Access Journals (Sweden)

    Etemadifar Masoud

    2010-02-01

    Full Text Available Abstract Objectives This review summarizes recent developments in platelet biology relevant to neuroinflammatory disorders. Multiple sclerosis (MS is taken as the "Poster Child" of these disorders but the implications are wide. The role of platelets in inflammation is well appreciated in the cardiovascular and cancer research communities but appears to be relatively neglected in neurological research. Organization After a brief introduction to platelets, topics covered include the matrix metalloproteinases, platelet chemokines, cytokines and growth factors, the recent finding of platelet PPAR receptors and Toll-like receptors, complement, bioactive lipids, and other agents/functions likely to be relevant in neuroinflammatory diseases. Each section cites literature linking the topic to areas of active research in MS or other disorders, including especially Alzheimer's disease. Conclusion The final section summarizes evidence of platelet involvement in MS. The general conclusion is that platelets may be key players in MS and related disorders, and warrant more attention in neurological research.

  13. A wide angle low coherence interferometry based eye length optometer

    Science.gov (United States)

    Meadway, Alexander; Siegwart, John; Wildsoet, Christine; Norton, Thomas; Zhang, Yuhua

    2015-03-01

    Interest in eye growth regulation has burgeoned with the rise in myopia prevalence world-wide. Eye length and eye shape are fundamental metrics for related research, but current in vivo measurement techniques are generally limited to the optical axis of the eye. We describe a high resolution, time domain low coherence interferometry based optometer for measuring the eye length of small animals over a wide field of view. The system is based upon a Michelson interferometer using a superluminescent diode as a source, including a sample arm and a reference arm. The sample arm is split into two paths by a polarisation beam splitter; one focuses the light on the cornea and the other focuses the light on the retina. This method has a high efficiency of detection for reflections from both surfaces. The reference arm contains a custom high speed linear motor with 25 mm stroke and equipped with a precision displacement encoder. Light reflected from the cornea and the retina is combined with the reference beam to generate low coherence interferograms. Two galvo scanners are employed to steer the light to different angles so that the eye length over a field of view of 20° × 20° can be measured. The system has an axial resolution of 6.8 μm (in air) and the motor provides accurate movement, allowing for precise and repeatable measurement of coherence peak positions. Example scans from a tree shrew are presented.

  14. EBG Enhanced Reflector Feeds for Wide Angle Scanning Applications

    NARCIS (Netherlands)

    Neto, A.; Ettorre, M.; Gerini, G.; Maagt, P.J. de

    2008-01-01

    This work is an extension of a series of works on the use of dielectric super-layers to shape the radiation pattern of each feed composing a focal plane imaging array. Using dielectric super-layers, the spill over from the reflectors are reduced without increasing the dimensions of each aperture. Th

  15. Low Cost, Wide Angle Infinity Optics Visual System.

    Science.gov (United States)

    1981-09-01

    straight edges of the sides that were to be joined. Mineral oil was used as the cooling fluid in the milling process to Prevent any possible water...maximum ana]e at the system eye noint of:16.2" 0 -6.2 x 500 , or 50.630. If the scannino format on the camera tube is not chanqed, it becomes nuite

  16. Wide-angle incidence and P-wave transmission

    Science.gov (United States)

    Xie, Jun-Fa; Sun, Cheng-Yu; Lin, Mei-Yan; Li, Jing-Jing

    2015-12-01

    Polarity reversals may occur to transmitted P waves if the incidence angle is greater than the critical incidence angle. We analyze the characteristics of reflection and transmission coefficients under the condition of wide incidence angle based on Zoeppritz equations. We find that for specific conditions, as the incidence angle increases, the characteristic curve of the transmitted P-wave coefficient enters the third quadrant from the first quadrant through the origin, which produces a transition in the transmitted P wave and the corresponding coefficient experiences polarity reversal. We derive the incidence angle when the transmitted P-wave coefficient is zero and verify that it equals zero by using finite-difference forward modeling for a single-interface model. We replace the water in the model reservoir by gas and see that the reservoir P-wave velocity and density decrease dramatically. By analyzing the synthetic seismogram of the transmitted P wave in the single-interface model, we show that the gas-saturated reservoir is responsible for polarity reversal.

  17. Wide angle Michelson Doppler imaging interferometer. [measuring atmospheric emissions

    Science.gov (United States)

    Shepherd, G. G.

    1980-01-01

    The optical system, stepping control, phase and modulation depth, array detector, and directions sensor are described for a specialized type of Michelson interferometer which works at sufficiently high resolution to measure the line widths and Doppler shifts of naturally occurring atmospheric emissions. With its imaging capability, the instrument can potentially supply this data independently for each element of the 100 x 100 detector array. The experiment seeks: (1) to obtain vertical profiles of atmospheric winds and temperatures as functions of latitude by observing near the limb; (2) to acquire exploratory wind and temperature data on smaller scale structures in airglow irregularities and in auroral forms; and (3) to collaborate with other Spacelab experiments, such as barium cloud releases, in providing wind and temperature data.

  18. Kirigami Nanocomposites as Wide-Angle Diffraction Gratings.

    Science.gov (United States)

    Xu, Lizhi; Wang, Xinzhi; Kim, Yoonseob; Shyu, Terry C; Lyu, Jing; Kotov, Nicholas A

    2016-06-28

    Beam steering devices represent an essential part of an advanced optics toolbox and are needed in a spectrum of technologies ranging from astronomy and agriculture to biosensing and networked vehicles. Diffraction gratings with strain-tunable periodicity simplify beam steering and can serve as a foundation for light/laser radar (LIDAR/LADAR) components of robotic systems. However, the mechanical properties of traditional materials severely limit the beam steering angle and cycle life. The large strain applied to gratings can severely impair the device performance both in respect of longevity and diffraction pattern fidelity. Here, we show that this problem can be resolved using micromanufactured kirigami patterns from thin film nanocomposites based on high-performance stiff plastics, metals, and carbon nanotubes, etc. The kirigami pattern of microscale slits reduces the stochastic concentration of strain in stiff nanocomposites including those made by layer-by-layer assembly (LBL). The slit patterning affords reduction of strain by 2 orders of magnitude for stretching deformation and consequently enables reconfigurable optical gratings with over a 100% range of period tunability. Elasticity of the stiff nanocomposites and plastics makes possible cyclic reconfigurability of the grating with variable time constant that can also be referred to as 4D kirigami. High-contrast, sophisticated diffraction patterns with as high as fifth diffraction order can be obtained. The angular range of beam steering can be as large as 6.5° for a 635 nm laser beam compared to ∼1° in surface-grooved elastomer gratings and ∼0.02° in MEMS gratings. The versatility of the kirigami patterns, the diversity of the available nanocomposite materials, and their advantageous mechanical properties of the foundational materials open the path for engineering of reconfigurable optical elements in LIDARs essential for autonomous vehicles and other optical devices with spectral range determined by the kirigami periodicity.

  19. Broadband Wide Angle Lens Implemented with Dielectric Metamaterials

    Directory of Open Access Journals (Sweden)

    Anthony Starr

    2011-08-01

    Full Text Available The Luneburg lens is a powerful imaging device, exhibiting aberration free focusing for parallel rays incident from any direction. However, its advantages are offset by a focal surface that is spherical and thus difficult to integrate with standard planar detector and emitter arrays. Using the recently developed technique of transformation optics, it is possible to transform the curved focal surface to a flat plane while maintaining the perfect focusing behavior of the Luneburg over a wide field of view. Here we apply these techniques to a lesser-known refractive Luneburg lens and implement the design with a metamaterial composed of a semi-crystalline distribution of holes drilled in a dielectric. In addition, we investigate the aberrations introduced by various approximations made in the implementation of the lens. The resulting design approach has improved mechanical strength with small aberrations and is ideally suited to implementation at infrared and visible wavelengths.

  20. Broadband Wide Angle Lens Implemented with Dielectric Metamaterials

    Science.gov (United States)

    Hunt, John; Kundtz, Nathan; Landy, Nathan; Nguyen, Vinh; Perram, Tim; Starr, Anthony; Smith, David R.

    2011-01-01

    The Luneburg lens is a powerful imaging device, exhibiting aberration free focusing for parallel rays incident from any direction. However, its advantages are offset by a focal surface that is spherical and thus difficult to integrate with standard planar detector and emitter arrays. Using the recently developed technique of transformation optics, it is possible to transform the curved focal surface to a flat plane while maintaining the perfect focusing behavior of the Luneburg over a wide field of view. Here we apply these techniques to a lesser-known refractive Luneburg lens and implement the design with a metamaterial composed of a semi-crystalline distribution of holes drilled in a dielectric. In addition, we investigate the aberrations introduced by various approximations made in the implementation of the lens. The resulting design approach has improved mechanical strength with small aberrations and is ideally suited to implementation at infrared and visible wavelengths. PMID:22164056

  1. Broadband Wide Angle Lens Implemented with Dielectric Metamaterials

    OpenAIRE

    Anthony Starr; Nathan Landy; Vinh Nguyen; Tim Perram; Nathan Kundtz; John Hunt; Smith, David R.

    2011-01-01

    The Luneburg lens is a powerful imaging device, exhibiting aberration free focusing for parallel rays incident from any direction. However, its advantages are offset by a focal surface that is spherical and thus difficult to integrate with standard planar detector and emitter arrays. Using the recently developed technique of transformation optics, it is possible to transform the curved focal surface to a flat plane while maintaining the perfect focusing behavior of the Luneburg over a wide fi...

  2. Initial State Helicity Correlation in Wide Angle Compton Scattering

    Science.gov (United States)

    Zhang, Jixie; Day, Donal; Keller, Dustin; Rondon, Oscar

    2014-09-01

    The applicability of pQCD to exclusive reactions at medium energies is a subject of considerable interest. Real Compton scattering (RCS) has the potential to provide insight to this unsettled issue. In pQCD, three active quarks and two hard gluons are involved when describing RCS. But the cross sections do not agree with the pQCD predictions. In contrast, a handbag dominance model, involving only one single quark coupling to the spectator through generalized parton distributions (GPDs) does a good job of matching the cross section data. A measurement of the longitudinal polarization transfer parameter KLL was found inconsistent with predictions of pQCD yet consistent with calculations within the hand-bag mechanism. Further Miller's handbag approach, which including quark and hadron helicity flip, contradicts pQCD and others which demands that KLL =ALL , the initial state helicity correlation asymmetry, by finding that KLL ≠ALL . The first ever measurement of ALL has been proposed to run in Jefferson Lab's Hall C. This experiment will utilize an untagged bremsstrahlung photon beam and the longitudinally polarized UVA/JLAB proton target. After a brief introduction to the physics, the experiment will be described and the expected results presented.

  3. Design and Analysis of Printed Yagi-Uda Antenna and Two-Element Array for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Cai Run-Nan

    2012-01-01

    Full Text Available A printed director antenna with compact structure is proposed. The antenna is fed by a balanced microstrip-slotline and makes good use of space to reduce feeding network area and the size of antenna. According to the simulation results of CST MICROWAVE STUDIO software, broadband characteristics and directional radiation properties of the antenna are explained. The operating bandwidth is 1.8 GHz–3.5 GHz with reflection coefficient less than −10 dB. Antenna gain in band can achieve 4.5–6.8 dBi, and the overall size of antenna is smaller than 0.34λ0×0.58λ0. Then the antenna is developed to a two-element antenna array, working frequency and relative bandwidth of which are 2.15–2.87 GHz and 28.7%, respectively. Compared with antenna unit, the gain of the antenna array has increased by 2 dB. Thus the proposed antenna has characteristics of compact structure, relatively small size, and wideband, and it can be widely used in PCS/UMTS/WLAN/ WiMAX fields.

  4. Gamma-Ray Telescopes: 400 Years of Astronomical Telescopes

    Science.gov (United States)

    Gehrels, Neil; Cannizzo, John K.

    2010-01-01

    The last half-century has seen dramatic developments in gamma-ray telescopes, from their initial conception and development through to their blossoming into full maturity as a potent research tool in astronomy. Gamma-ray telescopes are leading research in diverse areas such as gamma-ray bursts, blazars, Galactic transients, and the Galactic distribution of Al-26.

  5. Using 25G vitrectomy for the Valsalva retinal disease with the help of Resight non-contact wide angle lenses%Resight非接触广角镜下行25G玻璃体切割治疗Valsalva视网膜病变

    Institute of Scientific and Technical Information of China (English)

    毛新帮; 赵菊莲; 游志鹏

    2014-01-01

    目的 观察Resight非接触广角镜下行25G玻璃体切割术治疗严重Valsalva视网膜病变的效果.方法 回顾性分析2011年7月至2012年12月在南昌大学附属医院眼科应用Resight非接触广角镜下,行25G玻璃体切割术治疗8例8只眼严重Valsalva视网膜病变眼的临床资料.患者中男性6例,女性2例;年龄24~48岁,平均年龄35岁;右眼5只,左眼3只;最佳矫正视力为眼前手动至眼前指数;发病时间23 ~60天,平均42天;所有患者均经病史咨询和眼底荧光血管造影、眼底照相、眼科B超等检查,确诊为严重的Valsalva视网膜病变.患眼黄斑部均大面积视网膜前出血,经ND:YAG激光治疗或药物保守治疗积血未消退,而后接受在Resight非接触广角镜下行25G玻璃体切割术.手术方式为闭合三通道玻璃体切割术,术毕玻璃体腔未注射任何药物,也未使用任何填充物.术后随访观察2~12个月,平均8个月.结果 在Resight非接触广角镜下用25G玻璃体切割手术治疗严重的Valsalva视网膜病变,手术时间最短10 min,最长16 min,平均手术时间为12 min.术后视力均显著提高,末次最佳矫正视力3只眼为0.9,4只眼为1.0,1只眼为1.2;所有患者黄斑部出血完全消退,眼底荧光血管造影未发现明显异常;术后眼压均正常,术后2周内有1只眼出现轻度玻璃体混浊,1个月后消退,无视网膜脱离、并发性白内障等并发症发生.结论 在Resight非接触广角镜下行25G玻璃体切割手术治疗严重的Valsalva视网膜病变,其广角系统及微创玻璃体切割系统的有机结合,能明显缩短手术时间,快速恢复视力,而且并发症少,是治疗严重Valsalva视网膜病变的安全、有效方法.%Objective To observe the effect of 25G vitrectomy for the serious Valsalva retinal disease with the help of Resight non-contact wide angle lenses.Methods Retrospectively analyzed the clinical data of 8 cases (8 eyes) with the serious Valsalva

  6. Building Medium Size Telescope Structures for the Cherenkov Telescope Array

    CERN Document Server

    Schulz, A; Oakes, L; Schlenstedt, S; Schwanke, U

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the future instrument in ground-based gamma-ray astronomy in the energy range from 20 GeV to 300 TeV. Its sensitivity will surpass that of current generation experiments by a factor $\\sim$10, facilitated by telescopes of three sizes. The performance in the core energy regime will be dominated by Medium Size Telescopes (MST) with a reflector of 12 m diameter. A full-size mechanical prototype of the telescope structure has been constructed in Berlin. The performance of the prototype is being evaluated and optimisations, among others, facilitating the assembly procedure and mass production possibilities are being implemented. We present the current status of the developments from prototyping towards pre-production telescopes, which will be deployed at the final site.

  7. The neutrino telescope ANTARES

    Directory of Open Access Journals (Sweden)

    Gleixner Andreas

    2014-04-01

    Full Text Available The ANTARES neutrino telescope is currently the largest neutrino detector in the Northern Hemisphere. The detector consists of a three-dimensional array of 885 photomultiplier tubes, distributed along 12 lines, located at a depth of 2500 m in the Mediterranean Sea. The purpose of the experiment is the detection of high-energy cosmic neutrinos. The detection principle is based on the observation of Cherenkov-Light emitted by muons resulting from charged-current interactions of muon neutrinos in the vicinity of the detection volume. The main scientific targets of ANTARES include the search for astrophysical neutrino point sources, the measurement of the diffuse neutrino flux and the indirect search for dark matter.

  8. The ANTARES neutrino telescope

    CERN Document Server

    Zornoza, Juan de Dios

    2012-01-01

    The ANTARES collaboration completed the installation of the first neutrino detector in the sea in 2008. It consists of a three dimensional array of 885 photomultipliers to gather the Cherenkov photons induced by relativistic muons produced in charged-current interactions of high energy neutrinos close to/in the detector. The scientific scope of neutrino telescopes is very broad: the origin of cosmic rays, the origin of the TeV photons observed in many astrophysical sources or the nature of dark matter. The data collected up to now have allowed us to produce a rich output of physics results, including the map of the neutrino sky of the Southern hemisphere, search for correlations with GRBs, flaring sources, gravitational waves, limits on the flux produced by dark matter self-annihilations, etc. In this paper a review of these results is presented.

  9. Composite telescope technology

    Science.gov (United States)

    Chen, Peter C.; Rabin, Douglas

    2014-07-01

    We report the development of optical mirrors based on polymer matrix composite materials. Advantages of this technology are low cost and versatility. By using appropriate combinations of polymers and various metallic and nonmetallic particles and fibers, the properties of the materials can be tailored to suit a wide variety of applications. We report the fabrication and testing of flat and curved mirrors made with metal powders, multiple mirrors replicated with high degree of uniformity from the same mandrels, cryogenic testing, mirrors made of ferromagnetic materials that can be actively or adaptively controlled by non-contact actuation, optics with very smooth surfaces made by replication, and by spincasting. We discuss development of a new generation of ultra-compact, low power active optics and 3D printing of athermal telescopes.

  10. Spectroradiometry with Space Telescopes

    CERN Document Server

    Pauluhn, Anuschka; Smith, Peter L; Colina, Luis

    2015-01-01

    Radiometry has been of fundamental importance in astronomy from the early beginnings. Initially, astronomers had their own radiometric system, based on extraterrestrial standards, namely the irradiance of stars expressed in visual magnitudes. Observing and comparing magnitudes in specific spectral bands then led to the astronomical spectrophotometry. The advent of astronomical high-resolution spectroscopy offered the possibility to interpret observations through physical models of stellar atmospheres. Such models had to be constructed based on physics-related units, and such units, rather than magnitudes, were then used for observational tests of the models. In this review, we provide an overview of how to achieve a valid laboratory calibration, and discuss ways to reliably extend this calibration to the spectroscopic telescope's performance in space. Recently, the quest for independent calibrations traceable to laboratory standards has become a well-supported aim, and has led to plans for now also launching ...

  11. Infrared up-conversion telescope

    DEFF Research Database (Denmark)

    2014-01-01

    There is presented to an up-conversion infrared telescope (110) arranged for imaging an associated scene (130), wherein the up-conversion infrared telescope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein a first optical...

  12. European Solar Telescope: Progress status

    NARCIS (Netherlands)

    Collados, M.; Bettonvil, F.C.M.; Cavaller, L.; Ermolli, I.; Gelly, B.; Pérez, A.; Socas-Navarro, H.; Soltau, D.; Volkmer, R.

    2010-01-01

    In this paper, the present status of the development of the design of the European Solar Telescope is described. The telescope is devised to have the best possible angular resolution and polarimetric performance, maximizing the throughput of the whole system. To that aim, adaptive optics and multi-c

  13. Seismic Imager Space Telescope

    Science.gov (United States)

    Sidick, Erkin; Coste, Keith; Cunningham, J.; Sievers,Michael W.; Agnes, Gregory S.; Polanco, Otto R.; Green, Joseph J.; Cameron, Bruce A.; Redding, David C.; Avouac, Jean Philippe; Ampuero, Jean Paul; Leprince, Sebastien; Michel, Remi

    2012-01-01

    A concept has been developed for a geostationary seismic imager (GSI), a space telescope in geostationary orbit above the Pacific coast of the Americas that would provide movies of many large earthquakes occurring in the area from Southern Chile to Southern Alaska. The GSI movies would cover a field of view as long as 300 km, at a spatial resolution of 3 to 15 m and a temporal resolution of 1 to 2 Hz, which is sufficient for accurate measurement of surface displacements and photometric changes induced by seismic waves. Computer processing of the movie images would exploit these dynamic changes to accurately measure the rapidly evolving surface waves and surface ruptures as they happen. These measurements would provide key information to advance the understanding of the mechanisms governing earthquake ruptures, and the propagation and arrest of damaging seismic waves. GSI operational strategy is to react to earthquakes detected by ground seismometers, slewing the satellite to point at the epicenters of earthquakes above a certain magnitude. Some of these earthquakes will be foreshocks of larger earthquakes; these will be observed, as the spacecraft would have been pointed in the right direction. This strategy was tested against the historical record for the Pacific coast of the Americas, from 1973 until the present. Based on the seismicity recorded during this time period, a GSI mission with a lifetime of 10 years could have been in position to observe at least 13 (22 on average) earthquakes of magnitude larger than 6, and at least one (2 on average) earthquake of magnitude larger than 7. A GSI would provide data unprecedented in its extent and temporal and spatial resolution. It would provide this data for some of the world's most seismically active regions, and do so better and at a lower cost than could be done with ground-based instrumentation. A GSI would revolutionize the understanding of earthquake dynamics, perhaps leading ultimately to effective warning

  14. Operating a heterogeneous telescope network

    Science.gov (United States)

    Allan, Alasdair; Bischoff, Karsten; Burgdorf, Martin; Cavanagh, Brad; Christian, Damien; Clay, Neil; Dickens, Rob; Economou, Frossie; Fadavi, Mehri; Frazer, Stephen; Granzer, Thomas; Grosvenor, Sandy; Hessman, Frederic V.; Jenness, Tim; Koratkar, Anuradha; Lehner, Matthew; Mottram, Chris; Naylor, Tim; Saunders, Eric S.; Solomos, Nikolaos; Steele, Iain A.; Tuparev, Georg; Vestrand, W. Thomas; White, Robert R.; Yost, Sarah

    2006-06-01

    In the last few years the ubiquitous availability of high bandwidth networks has changed the way both robotic and non-robotic telescopes operate, with single isolated telescopes being integrated into expanding "smart" telescope networks that can span continents and respond to transient events in seconds. The Heterogeneous Telescope Networks (HTN)* Consortium represents a number of major research groups in the field of robotic telescopes, and together we are proposing a standards based approach to providing interoperability between the existing proprietary telescope networks. We further propose standards for interoperability, and integration with, the emerging Virtual Observatory. We present the results of the first interoperability meeting held last year and discuss the protocol and transport standards agreed at the meeting, which deals with the complex issue of how to optimally schedule observations on geographically distributed resources. We discuss a free market approach to this scheduling problem, which must initially be based on ad-hoc agreements between the participants in the network, but which may eventually expand into a electronic market for the exchange of telescope time.

  15. Why systems engineering on telescopes?

    Science.gov (United States)

    Swart, Gerhard P.; Meiring, Jacobus G.

    2003-02-01

    Although Systems Engineering has been widely applied to the defence industry, many other projects are unaware of its potential benefits when correctly applied, assuming that it is an expensive luxury. It seems that except in a few instances, telescope projects are no exception, prompting the writing of this paper. The authors postulate that classical Systems Engineering can and should be tailored, and then applied to telescope projects, leading to cost, schedule and technical benefits. This paper explores the essence of Systems Engineering and how it can be applied to any complex development project. The authors cite real-world Systems Engineering examples from the Southern African Large Telescope (SALT). The SALT project is the development and construction of a 10m-class telescope at the price of a 4m telescope. Although SALT resembles the groundbreaking Hobby-Eberly Telescope (HET) in Texas, the project team are attempting several challenging changes to the original design, requiring a focussed engineering approach and discernment in the definition of the telescope requirements. Following a tailored Systems Engineering approach on this project has already enhanced the quality of decisions made, improved the fidelity of contractual specifications for subsystems, and established criteria testing their performance. Systems Engineering, as applied on SALT, is a structured development process, where requirements are formally defined before the award of subsystem developmental contracts. During this process conceptual design, modeling and prototyping are performed to ensure that the requirements were realistic and accurate. Design reviews are held where the designs are checked for compliance with the requirements. Supplier factory and on-site testing are followed by integrated telescope testing, to verify system performance against the specifications. Although the SALT project is still far from completion, the authors are confident that the present benefits from

  16. Formation flight astronomical survey telescope

    Science.gov (United States)

    Tsunemi, Hiroshi

    2012-03-01

    Formation Flight Astronomical Survey Telescope (FFAST) is a project for hard X-ray observation. It consists of two small satellites; one (telescope satellite) has a super mirror covering the energy range up to 80 keV while the other (detector satellite) has an scintillator deposited CCD (SDCCD) having good spatial resolution and high efficiency up to 100 keV. Two satellites will be put into individual Kepler orbits forming an X-ray telescope with a focal length of 20 m. They will be not in pointing mode but in survey mode to cover a large sky region.

  17. The Automatic Telescope Network (ATN)

    CERN Document Server

    Mattox, J R

    1999-01-01

    Because of the scheduled GLAST mission by NASA, there is strong scientific justification for preparation for very extensive blazar monitoring in the optical bands to exploit the opportunity to learn about blazars through the correlation of variability of the gamma-ray flux with flux at lower frequencies. Current optical facilities do not provide the required capability.Developments in technology have enabled astronomers to readily deploy automatic telescopes. The effort to create an Automatic Telescope Network (ATN) for blazar monitoring in the GLAST era is described. Other scientific applications of the networks of automatic telescopes are discussed. The potential of the ATN for science education is also discussed.

  18. Bhavnagar Telescope: the most widely travelled telescope in the country

    CERN Document Server

    Rao, N Kameswara; Vagiswari, A

    2014-01-01

    In the last decade of the 19th century Maharaja Takhtasingji Observatory was built at Poona (1888-1912) under the supervision of K.D.Naegamavala, with the grant from Maharaja of Bhavnagar (from where the name Bhavnagar Telescope must have originated. The story of this telescope from its inception to the current status is traced. IIA Archives has been extensively used to resource information for this note.

  19. Ice Middleware in the New Solar Telescope's Telescope Control System

    Science.gov (United States)

    Shumko, S.

    2009-09-01

    The Big Bear Solar Observatory (BBSO) is now in the process of assembling and aligning its 1.6 m New Solar Telescope (NST). There are many challenges controlling NST and one of them is establishing reliable and robust communications between different parts of the Telescope Control System (TCS). For our TCS we selected Ice (Internet communication engine) from ZeroC, Inc. In this paper we discuss advantages of the Ice middleware, details of implementation and problems we face implementing it.

  20. The small size telescope projects for the Cherenkov Telescope Array

    CERN Document Server

    ,

    2015-01-01

    The small size telescopes (SSTs), spread over an area of several square km, dominate the CTA sensitivity in the photon energy range from a few TeV to over 100 TeV, enabling for the detailed exploration of the very high energy gamma-ray sky. The proposed telescopes are innovative designs providing a wide field of view. Two of them, the ASTRI (Astrophysics con Specchi a Tecnologia Replicante Italiana) and the GCT (Gamma-ray Cherenkov Telescope) telescopes, are based on dual mirror Schwarzschild-Couder optics, with primary mirror diameters of 4 m. The third, SST-1M, is a Davies-Cotton design with a 4 m diameter mirror. Progress with the construction and testing of prototypes of these telescopes is presented. The SST cameras use silicon photomultipliers, with preamplifier and readout/trigger electronics designed to optimize the performance of these sensors for (atmospheric) Cherenkov light. The status of the camera developments is discussed. The SST sub-array will consist of about 70 telescopes at the CTA souther...

  1. Lightweighted ZERODUR for telescopes

    Science.gov (United States)

    Westerhoff, T.; Davis, M.; Hartmann, P.; Hull, T.; Jedamzik, R.

    2014-07-01

    The glass ceramic ZERODUR® from SCHOTT has an excellent reputation as mirror blank material for earthbound and space telescope applications. It is known for its extremely low coefficient of thermal expansion (CTE) at room temperature and its excellent CTE homogeneity. Recent improvements in CNC machining at SCHOTT allow achieving extremely light weighted substrates up to 90% incorporating very thin ribs and face sheets. In 2012 new ZERODUR® grades EXPANSION CLASS 0 SPECIAL and EXTREME have been released that offer the tightest CTE grades ever. With ZERODUR® TAILORED it is even possible to offer ZERODUR® optimized for customer application temperature profiles. In 2013 SCHOTT started the development of a new dilatometer setup with the target to drive the industrial standard of high accuracy thermal expansion metrology to its limit. In recent years SCHOTT published several paper on improved bending strength of ZERODUR® and lifetime evaluation based on threshold values derived from 3 parameter Weibull distribution fitted to a multitude of stress data. ZERODUR® has been and is still being successfully used as mirror substrates for a large number of space missions. ZERODUR® was used for the secondary mirror in HST and for the Wolter mirrors in CHANDRA without any reported degradation of the optical image quality during the lifetime of the missions. Some years ago early studies on the compaction effects of electron radiation on ZERODUR® were re analyzed. Using a more relevant physical model based on a simplified bimetallic equation the expected deformation of samples exposed in laboratory and space could be predicted in a much more accurate way. The relevant ingredients for light weighted mirror substrates are discussed in this paper: substrate material with excellent homogeneity in its properties, sufficient bending strengths, space radiation hardness and CNC machining capabilities.

  2. Telescopic drilling rod

    Energy Technology Data Exchange (ETDEWEB)

    Kagan, I.L.; Berezov, S.I.; Gavrilov, G.A.; Goykhman, Ya.A.; Makushkin, D.O.; Rachev, M.P.; Voynich, L.K.

    1981-09-07

    The telescopic drilling rod includes an inner section of the rod, in whose center cable has been passed and is attached a bearing assembly connecting it to the winch, outer section of rod along which there is pipeline connecting the working cavity formed by the inner section of rod and the housing, installed on the lower end of the outer section of rod, with cavity formed by framework of the guide swivel and end piece and connected to the hydraulic system of the machine by pipeline, as well as clamping elements. In order to drill wells to a depth greater than the length of the outer sectrion of the rod, the latter jointly with the inner section of rod is lowered into the extreme lower position until swivel rests on the feed mechanism. With further slipping of cable and the absence of pressure in the hydraulic system, clamping elements do not have an effect on the inner section of rod. It has the opportunity to freely move along the outer section of rod downwards to the face. When pressure is supplied on pipeline into cavity and further through pipeline into working cavity, the inner section of rod is clamped with feed of the outer section in the process of drilling, both sections move jointly. Because of the link between working cavity of sleeve installed on the lower end of the outer section of rod, and the hydraulic system of the machine through the swivel cavity, it is possible to fix the drilling rod in any mutual axial position of the section.

  3. BCK Network of Optical Telescopes

    Science.gov (United States)

    McGruder, Charles H.; Antoniuk, Krill; Carini, Michael T.; Gelderman, Richard; Hammond, Benjamin; Hicks, Stacy; Laney, David; Shakhovskoy, David; Strolger, Louis-Gregory; Williams, Joshua

    2015-01-01

    The BCK network consists of three research grade telescopes: 0.6m (B) at the Bell Observatory near Western Kentucky University (WKU), 1.3m (C) at the Crimean Astrophysical Observatory and a 1.3m (K) at Kitt Peak National Observatory. The Bell Telescope is operated remotely from WKU while the Robotically Controlled Telescope (RCT) at Kitt Peak possesses an autonomous scheduler. The BCK telescopes are distributed longitudinally over 145º and can be used to observe continuously up to 21.2 hours/day. The network will be chiefly employed to observe variable stars, blazars and unpredictable celestial events.Because celestial objects with ground-based telescopes cannot be observed optically during the daytime, continuous ground-based astronomical observations are only possible via a network of longitudinally distributed telescopes. When the sun rises in Crimea after it sets at Bell, continuous observations are possible. This occurs for about six and ½ months per year - mid September to early April. A network is highly desirable for events that are not predictable for instance the appearance of supernovae, gamma-ray bursts, or undiscovered exoplanetsVariable stars are really only known in significant numbers to about 14 mag. But, as the magnitude increases the number of stars in any field increases very sharply, so there are many variable stars to discover at faint magnitude (m > 14). Discovering new variables makes great undergraduate student projects, a major component of astronomical research at WKU. In addition, pinning down the periods of variable stars is greatly facilitated with a network of telescopes.The BCK telescope network will also be used for monitoring the optical variability of blazars. The network provides increased coverage on daily variability timescales by minimizing interruptions due to weather and or mechanical problems at any one observatory and is used for obtaining continuous (12+ hours) of observations of rapid variability in blazars which would

  4. Hubble Space Telescope-Illustration

    Science.gov (United States)

    1989-01-01

    This illustration depicts a side view of the Hubble Space Telescope (HST). The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

  5. The Large Binocular Telescope Project

    Science.gov (United States)

    Hill, J. M.

    1995-05-01

    The Large Binocular Telescope (LBT) Project has evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 x 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train --- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in spring of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximicrons flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximicrons stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1995 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson) and ADS Italia

  6. The calculus of telescopic urbanism

    OpenAIRE

    Arabindoo, P.

    2013-01-01

    Developing Amin's invocation of a telescopic urbanism as more than a visual metaphor, this paper seeks to rethink its epistemological and methodological focus, resisting at the same time the tendency to oversimplify the relationship between the different optics he outlines. Threatened by a dominant meta-narrative of a numerically driven calculus, this paper identifies an opportunity in Amin's telescopic urbanism to reject the 'big-data' approach to the city. In this context, it challenges the...

  7. Demonstration Telescopes Using "Dollar Optics"

    Science.gov (United States)

    Ross, Paul

    2008-05-01

    I propose a poster that illustrates the use of "dollar optics” for experimentation and for the creation of demonstration telescopes. Handling a variety of lenses and mirrors provides an opportunity for discovering practical optics. Some part of this path of exploration must have been traveled by Galileo as he experimented with spectacle lenses. "Dollar optics” include reading glasses (positive meniscus lenses), convex and concave mirrors, Fresnel sheets, magnifying lenses, and eye loupes. Unwanted distance spectacles (negative meniscus lenses) are available at second-hand stores. Galileo telescopes, "long” 17th century telescopes, and useful demonstration models of Newtonian reflectors can be made with "dollar” optics. The poster will illustrate practical information about "dollar optics” and telescopes: magnification, focal length, and "diopters” disassembling spectacles; creating cheap mounts for spectacle lenses; the importance of optical axes and alignment; eyepieces; and focusing. (A table would be useful with the poster to set out a hands-on display of "dollar optic” telescopes.) Educators, experimenters, and those concerned with astronomy outreach might be interested in this poster. Working with "dollar optics” requires facility with simple tools, interest in planning projects, patience, imagination, and the willingness to invest some time and effort. "Dollar optics” may help to foster creativity and hands-on enthusiasm - as did Galileo's work with simple lenses 400 years ago. "Oh! When will there be an end put to the new observations and discoveries of this admirable instrument?” - Galileo Galilei as quoted by Henry C. King, The History of the Telescope.

  8. The upgraded MAGIC Cherenkov telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Tescaro, D., E-mail: dtescaro@iac.es [Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain); Universidad de La Laguna (ULL), Dept. Astrofísica, E-38206 La Laguna, Tenerife (Spain)

    2014-12-01

    The MAGIC Cherenkov telescopes underwent a major upgrade in 2011 and 2012. A new 1039-pixel camera and a larger area digital trigger system were installed in MAGIC-I, making it essentially identical to the newer MAGIC-II telescope. The readout systems of both telescopes were also upgraded, with fully programmable receiver boards and DRS4-chip-based digitization systems. The upgrade eased the operation and maintenance of the telescopes and also improved significantly their performance. The system has now an integral sensitivity as good as 0.6% of the Crab Nebula flux (for E>400GeV), with an effective analysis threshold at 70 GeV. This allows MAGIC to secure one of the leading roles among the current major ground-based Imaging Atmospheric Cherenkov telescopes for the next 5–10 years. - Highlights: • In 2011 and 2012 the MAGIC telescopes underwent a two-stage major upgrade. • The new camera of MAGIC-I allows us to exploit a 1.4 larger trigger area. • The novel DRS4-based readout systems allow a cost-effective ultra-fast digitization. • The upgrade greatly improved the maintainability of the system. • MAGIC has now an optimal integral sensitivity of 0.6% of the Crab Nebula flux.

  9. SLAS Library Telescope Program (Abstract)

    Science.gov (United States)

    Small, J. S.

    2016-12-01

    (Abstract only) In the fall of 2014, I submitted to the members of the St. Louis Astronomical Society to take the $1,000 profit we had from a convention we had hosted and use it to purchase three telescopes to modify for a Library Telescope program that was invented by Mark Stowbridge and promoted by the New Hampshire Astronomical Society. I had met Mark at NEAF in 2012 when he was walking the floor demonstrating the telescope. We held meetings with three libraries, the St. Louis County Library system, the St. Louis Public Library system and an independent library in Kirkwood, Missouri. The response was overwhelming! SLCL responded with a request for ten telescopes and SLPL asked for five. We did our first build in October, 2014 and placed a total of eighteen telescopes. Since that time, SLAS has placed a total of eighty-eight telescopes in library systems around the St. Louis Metro area, expanding into neighboring counties and across the river in Illinois. In this talk, I will discuss how to approach this project and put it in place in your libraries!

  10. Concept Design for SOAR Telescope

    Science.gov (United States)

    Sebring, T.; Cecil, G.; Krabbendam, V.; Moretto, G.

    1998-12-01

    The Southern Astrophysical Research (SOAR) telescope is a \\$28M collaboration between Brazil, NOAO, Michigan State University, and the University of North Carolina at Chapel Hill. NOAO will operate the telescope for 20 years in exchange for 30 astronomers.) The project is now fully funded. This f/16 telescope is optimized for high-quality images across the isokinetic field (0."17 FWHM degradation from the telescope+facility over a field of 7.5' diameter.) It is being designed to take up to 2 Gemini-class (2100 kg) instruments, or a combination of lighter instruments at 7 Nasmyth and bent Cassegrain foci. The facility is now under construction atop Cerro Pachon, 400m from Gemini-S. First light is currently scheduled for early 2002. Corning Inc. is preparing to fabricate the 4.2m-diameter, 7.5-10 cm thick primary mirror from ULE glass. In early 1999 contacts will be awarded for 2 major subsystems: active optics (which includes optics polishing), and the alt.-az. telescope mount. We will outline the novel strategies that are being used to control project costs while optimizing telescope performance. Instrumentation plans will also be summarized.

  11. The Research Productivity of Small Telescopes and Space Telescopes

    CERN Document Server

    Ringwald, F A; Lovell, R L; Kays, S A; Torres, Y V A

    2003-01-01

    We present statistics on the research productivity of astronomical telescopes. These were compiled by finding papers in which new data were presented, noting which telescopes were used, and then counting the number of papers, number of pages, and other statistics. The journals used were the Astronomical Journal, the Astrophysical Journal (including the Letters and Supplements), and the Publications of the Astronomical Society of the Pacific. We also compiled citations from the Science Citation Index. This work was designed to be similar to that of Trimble (1995), except that more recent journals (from 1995) and citations (from 1998) were used. We also did not restrict our sample to large telescopes only: we included all telescopes from which new data were presented, the smallest of which was a 0.1-m. The data were gathered by first-year work-study undergraduates, who were instructed to include data for all telescopes for which they found new data were included in the journals. A by-product of this research wa...

  12. Schwarzschild-Couder Telescope for the Cherenkov Telescope Array

    CERN Document Server

    Meagher, Kevin J

    2014-01-01

    The Cherenkov Telescope Array (CTA) is the next major ground-based observatory for gamma-ray astronomy. With CTA gamma-ray sources will be studied in the very-high energy gamma-ray range of a few tens of GeV to 100 TeV with up to ten times better sensitivity than available with current generation instruments. We discuss the proposed US contribution to CTA that comprises imaging atmospheric Cherenkov telescope with Schwarzschild-Couder (SC) optics. Key features of the SC telescope are a wide field of view of eight degrees, a finely pixelated camera with silicon photomultipliers as photon detectors, and a compact and power efficient 1 GS/s readout. The progress in both the optical system and camera development are discussed in this paper.

  13. Feature-based telescope scheduler

    Science.gov (United States)

    Naghib, Elahesadat; Vanderbei, Robert J.; Stubbs, Christopher

    2016-07-01

    Feature-based Scheduler offers a sequencing strategy for ground-based telescopes. This scheduler is designed in the framework of Markovian Decision Process (MDP), and consists of a sub-linear online controller, and an offline supervisory control-optimizer. Online control law is computed at the moment of decision for the next visit, and the supervisory optimizer trains the controller by simulation data. Choice of the Differential Evolution (DE) optimizer, and introducing a reduced state space of the telescope system, offer an efficient and parallelizable optimization algorithm. In this study, we applied the proposed scheduler to the problem of Large Synoptic Survey Telescope (LSST). Preliminary results for a simplified model of LSST is promising in terms of both optimality, and computational cost.

  14. Scientific management of Space Telescope

    Science.gov (United States)

    Odell, C. R.

    1981-01-01

    A historical summay is given on the science management of the Space Telescope, the inception of which began in 1962, when scientists and engineers first recommended the development of a nearly diffraction limited substantial-size optical telescope. Phase A, the feasibility requirements generation phase, began in 1971 and consisted largely of NASA scientists and a NASA design. Phase B, the preliminary design phase, established a tiered structure of scientists, led by the Large Space Telescope operations and Management Work Group. A Mission Operations Working Group headed six instrument definition teams to develop the essential instrument definitions. Many changes took place during Phase B, before design and development, which began in 1978 and still continues today.

  15. FAMOUS. The fluorescence telescope prototype

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Johannes; Bretz, Thomas; Hebbeker, Thomas; Lauscher, Markus; Middendorf, Lukas; Niggemann, Tim; Peters, Christine; Sommer, Dominik; Stephan, Maurice [III. Physikalisches Institut A, RWTH Aachen University (Germany); Auffenberg, Jan; Schaufel, Merlin [III. Physikalisches Institut B, RWTH Aachen University (Germany)

    2015-07-01

    One of the most successful techniques for the detection of air showers produced by ultra-high-energy cosmic rays are fluorescence telescopes. The light produced by de-exciting nitrogen in the atmosphere is typically detected by photomultiplier tubes (PMTs). This technique has been successfully used by the Pierre Auger Observatory in Argentina for many years. Silicon photomultipliers (SiPMs) promise higher photon detection efficiencies than PMTs. This and other advantages motivate the construction of the fluorescence telescope prototype FAMOUS (First Auger Multi-pixel photon counter camera for the Observation of Ultra-high-energy air Showers) which makes use of SiPMs. In this talk we discuss the FAMOUS telescope with a new 64-pixel camera including power supply and DAQ.

  16. LSST telescope and site status

    Science.gov (United States)

    Gressler, William J.

    2016-07-01

    The Large Synoptic Survey Telescope (LSST) Project1 received its construction authorization from the National Science Foundation in August 2014. The Telescope and Site (T and S) group has made considerable progress towards completion in subsystems required to support the scope of the LSST science mission. The LSST goal is to conduct a wide, fast, deep survey via a 3-mirror wide field of view optical design, a 3.2-Gpixel camera, and an automated data processing system. The summit facility is currently under construction on Cerro Pachón in Chile, with major vendor subsystem deliveries and integration planned over the next several years. This paper summarizes the status of the activities of the T and S group, tasked with design, analysis, and construction of the summit and base facilities and infrastructure necessary to control the survey, capture the light, and calibrate the data. All major telescope work package procurements have been awarded to vendors and are in varying stages of design and fabrication maturity and completion. The unique M1M3 primary/tertiary mirror polishing effort is completed and the mirror now resides in storage waiting future testing. Significant progress has been achieved on all the major telescope subsystems including the summit facility, telescope mount assembly, dome, hexapod and rotator systems, coating plant, base facility, and the calibration telescope. In parallel, in-house efforts including the software needed to control the observatory such as the scheduler and the active optics control, have also seen substantial advancement. The progress and status of these subsystems and future LSST plans during this construction phase are presented.

  17. LISA telescope spacer design investigations

    Science.gov (United States)

    Sanjuan, Josep; Mueller, Guido; Livas, Jeffrey; Preston, Alix; Arsenovic, Petar; Castellucci, Kevin; Generie, Joseph; Howard, Joseph; Stebbins, Robin

    The Laser Interferometer Space Antenna (LISA) is a space-based gravitational wave observa-tory with the goal of observing Gravitational Waves (GWs) from astronomical sources in a frequency range from 30 µHz to 0.1 Hz. The detection of GWs at such low frequency requires measurements of distances at the pico-meter level between bodies separated by 5 million kilo-meters. The LISA mission consists of three identical spacecraft (SC) separated by 5 × 106 km forming an equilateral triangle. Each SC contains two optical assemblies and two vacuum en-closures housing one proof mass (PM) in geodesic (free fall) motion each. The two assemblies on one SC are each pointing towards an identical assembly on each of the other two SC to form a non-equal arm interferometer. The measurement of the GW strain is done by measuring the change in the length of the optical path between the PMs of one arm relative to the other arms caused by the pass of a GW. An important element of the Interferometric Measurement System (IMS) is the telescope which, on one hand, gathers the light coming from the far SC (˜100 pW) and, on the other hand, expands and collimates the small outgoing beam ( 1 W) and sends it to the far SC. Due to the very demanding sensitivity requirements care must be taken in the design and validation of the telescope not to degrade the IMS performance. For instance, the diameter of the telescope sets the the shot noise of the IMS and depends critically on the diameter of the primary and the divergence angle of the outgoing beam. As the telescope is rather fast telescope, the divergence angle is a critical function of the overall separation between the primary and secondary. Any long term changes of the distance of more than a a few micro-meter would be detrimental to the LISA mission. Similarly challenging are the requirements on the in-band path-length noise for the telescope which has to be kept below 1 pm Hz-1/2 in the LISA band. Different configurations (on-axis/off axis

  18. The network of INTA telescopes

    Science.gov (United States)

    Cuesta, L.

    2008-06-01

    The Spanish Instituto Nacional de Técnica Aeroespacial has a network of three telescopes located at some of the best places for astronomy in mainland Spain. The first is at the Observatorio de Calar Alto in Almeria, at an altitude of more than 2100 m. The second is near Calatayud in Zaragoza, at the summit of a 1400-m high mountain. The last is on the campus of the Instituto Nacional de Técnica Aerospatial (INTA), in Madrid. The three telescopes are either 40 or 50 cm in diameter and will be available for communications and educational projects.

  19. Wide field of view telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, Mark R. (Albuquerque, NM); McGraw, John T. (Placitas, NM); Zimmer, Peter C. (Albuquerque, NM)

    2008-01-15

    A wide field of view telescope having two concave and two convex reflective surfaces, each with an aspheric surface contour, has a flat focal plane array. Each of the primary, secondary, tertiary, and quaternary reflective surfaces are rotationally symmetric about the optical axis. The combination of the reflective surfaces results in a wide field of view in the range of approximately 3.8.degree. to approximately 6.5.degree.. The length of the telescope along the optical axis is approximately equal to or less than the diameter of the largest of the reflective surfaces.

  20. Apollo Telescope Mount Spar Assembly

    Science.gov (United States)

    1969-01-01

    The Apollo Telescope Mount (ATM), designed and developed by the Marshall Space Flight Center, served as the primary scientific instrument unit aboard the Skylab. The ATM contained eight complex astronomical instruments designed to observe the Sun over a wide spectrum from visible light to x-rays. This image shows the ATM spar assembly. All solar telescopes, the fine Sun sensors, and some auxiliary systems are mounted on the spar, a cruciform lightweight perforated metal mounting panel that divides the 10-foot long canister lengthwise into four equal compartments. The spar assembly was nested inside a cylindrical canister that fit into the rack, a complex frame, and was protected by the solar shield.

  1. Superconductor lunar telescopes --Abstract only

    Science.gov (United States)

    Chen, P. C.; Pitts, R.; Shore, S.; Oliversen, R.; Stolarik, J.; Segal, K.; Hojaji, H.

    1994-01-01

    We propose a new type of telescope designed specifically for the lunar environment of high vacuum and low temperature. Large area UV-Visible-IR telescope arrays can be built with ultra-light-weight replica optics. High T(sub c) superconductors provide support, steering, and positioning. Advantages of this approach are light-weight payload compatible with existing launch vehicles, configurable large area optical arrays, no excavation or heavy construction, and frictionless electronically controlled mechanisms. We have built a prototype and will be demonstarting some of its working characteristics.

  2. Highlights from the Telescope Array

    Science.gov (United States)

    Matthews, J. N.

    2016-11-01

    The Telescope Array measures the properties of ultra high energy cosmic ray induced extensive air showers. We do this using a variety of techniques including an array of scintillator detectors to sample the footprint of the air shower when it reaches the Earth's surface and telescopes to measure the fluorescence and Cerenkov light of the air shower. From this we determine the energy spectrum and chemical composition of the primary particles. We also search for sources of cosmic rays and anisotropy. We have found evidence of a possible source of ultra high energy cosmic rays in the northern sky. The experiment and its most recent measurements will be discussed.

  3. Autonomous Dome for Robotic Telescope

    CERN Document Server

    Kumar, Akash; Ganesh, Shashikiran

    2016-01-01

    Physical Research Laboratory operates a 50cm robotic observatory at Mount Abu. This Automated Telescope for Variability Studies (ATVS) makes use of Remote Telescope System 2 (RTS2) for autonomous operations. The observatory uses a 3.5m dome from Sirius Observatories. We have developed electronics using Arduino electronic circuit boards with home grown logic and software to control the dome operations. We are in the process of completing the drivers to link our Arduino based dome controller with RTS2. This document is a short description of the various phases of the development and their integration to achieve the required objective.

  4. Results from the AMANDA telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, J.; Bai, X.; Barwick, S.W.; Becka, T.; Becker, K.-H.; Bernardini, E.; Bertrand, D.; Binon, F.; Biron, A.; Boeser, S.; Botner, O.; Bouhali, O.; Burgess, T.; Carius, S.; Castermans, T.; Chirkin, D.; Conrad, J.; Cooley, J.; Cowen, D.F.; Davour, A.; De Clercq, C.; DeYoung, T.; Desiati, P.; Dewulf, J.-P.; Ekstroem, P.; Feser, T.; Gaisser, T.K.; Ganupati, R.; Gaug, M.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Hallgren, A.; Halzen, F.; Hanson, K.; Hardtke, R.; Hauschildt, T.; Hellwig, M.; Herquet, Ph.; Hill, G.C.; Hulth, P.O.; Hultqvist, K.; Hundertmark, S.; Jacobsen, J.; Karle, A.; Koepke, L.; Kuehn, K.; Kowalski, M.; Lamoureux, J.I.; Leich, H.; Leuthold, M.; Lindahl, P.; Liubarsky, I.; Madsen, J.; Mandli, K.; Marciniewski, P.; Matis, H.S.; McParland, C.P.; Messarius, T.; Minaeva, Y.; Miocinovic, P.; Morse, R.; Nahnhauer, R.; Neunhoeffer, T.; Niessen, P.; Nygren, D.R.; Ogelman, H.; Olbrechts, Ph.; Perez de los Heros, C.; Pohl, A.C.; Price, P.B.; Przybylski, G.T.; Rawlins, K.; Resconi, E.; Rhode, W.; Ribordy, M.; Richter, S.; Rodriguez Martino, J.; Sander, H.-G.; Schmidt, T.; Schneider, D.; Schinarakis, K.; Schwarz, R.; Silvestri, A.; Solarz, M.; Spiczak, G.M.; Spiering, C.; Steele, D.; Steffen, P.; Stokstad, R.G.; Sudoff, P.; Sudoff, K.-H.; Sulanke, K.-H.; Taboada, I.; Thollander, L.; Tilav, S.; Wagner, W.; Walck, C.; Weinheimer, C.; Wiebusch, C.H.; Wiedemann, C.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Yodh, G.; Young, S

    2003-06-30

    We present results from the AMANDA high energy neutrino telescope located at the South Pole. They include measurements of the atmospheric neutrino flux, search for UHE point sources, and diffuse sources producing electromagnetic/hadronic showers at the detector or close to it.

  5. The Atacama Submillimeter Telescope Experiment

    Science.gov (United States)

    Sekimoto, Yutaro; Kawabe, Ryohei; Yamamoto, Satoshi; Hasegawa, Tetsuo

    1999-10-01

    We have a plan to operate a new 10 m telescope at Pampa la Bola (4800 m) in Chile as one of Japanese R&D activities for Atacama Large Millimeter/Submillimeter Array. Technical and scientific purposes in this experiment are to develop and evaluate a high precision 10 m antenna under exposed conditions at the site, to develop and test low-noise submillimeter receivers and new SIS photon detectors, to test various techniques for submillimeter observations, and to explore the southern hemisphere in the submillimeter band: Galactic Center, Magellanic Clouds, and so on. The SIS mixer receivers at the Cassegrain focus covers 100, 230, 350, 500, 670, and 810 GHz bands for spectral line observations. A digital autocorrelator consisted of four modules with 500 MHz bandwidth is mounted in a container near the telescope. Two power generators with a capability of 200 kW are installed at the site. The telescope will be operated remotely from Japan via a commercial satellite communication system. After a test operation at Nobeyama for one and a half years, the telescope will be transported to Pampa la Bola in August 2001.

  6. Cern Axion Solar Telescope (CAST)

    CERN Multimedia

    2002-01-01

    The CERN Solar Axion Telescope, CAST, aims to shed light on a 30-year-old riddle of particle physics by detecting axions originating from the 15 million degree plasma in the Sun 's core. Axions were proposed as an extension to the Standard Model of particle physics to explain why CP violation is observed in weak but not strong interactions.

  7. Monster telescope hunts blue planets

    CERN Multimedia

    Leake, J

    2003-01-01

    BRITAIN is to back a project to build the world's biggest telescope - so powerful that it could see life-bearing planets in other solar systems. It will need the largest mirror ever built at about 100 metres in diameter (1/2 page).

  8. Push-To Telescope Mathematics

    Science.gov (United States)

    Teets, Donald

    2012-01-01

    Two coordinate systems are related here, one defined by the earth's equator and north pole, the other by the orientation of a telescope at some location on the surface of the earth. Applying an interesting though somewhat obscure property of orthogonal matrices and using the cross-product simplifies this relationship, revealing that a surprisingly…

  9. Results from the AMANDA telescope

    CERN Document Server

    Bouhali, O

    2003-01-01

    We present results from the AMANDA high energy neutrino telescope located at the South Pole. They include measurements of the atmospheric neutrino flux, search for UHE point sources, and diffuse sources producing electromagnetic/hadronic showers at the detector or close to it. (4 refs).

  10. NESTOR Neutrino Telescope Status Report

    Science.gov (United States)

    Grieder, P. K. F.; NESTOR Collaboration; Aloupis, A.; Anassontzis, E. G.; Arvanitis, N.; Babalis, A.; Ball, A.; Bourlis, G.; Butkevich, A. V.; Chinowsky, W.; Christopoulos, P. E.; Darsaklis, A.; Dedenko, L. G.; Elistrup, D.; Fahrun, E.; Gialis, J.; Goudis, Ch.; Grammatikakis, G.; Green, C.; Karaevsky, S. K.; Katrivanos, P.; Keussen, U.; Kiskiras, J.; Knutz, Th.; Kolostelov, D.; Komlev, K.; Kontaxis, J.; Koske, P.; Learned, J. G.; Ledenev, V. V.; Leisos, A.; Limberopoulos, G.; Ludvig, J.; Makris, J.; Manousakis-Katsikakis, A.; Markopoulos, E.; Matsuno, S.; Mielke, J.; Mihos, Th.; Minkowski, P.; Mironovich, A. A.; Mitiguy, R.; Nounos, S.; Nygren, D. R.; Papageorgiou, K.; Passera, M.; Politis, C.; Preve, P.; Przybylski, G. T.; Rathlev, J.; Resvanis, L. K.; Rosen, M.; Schmidt, N.; Schmidt, Th.; Siotis, I.; Sopher, J.; Staveris, T.; Stavrakakis, G.; Stokstad, R.; Surin, N. M.; Tsagli, V.; Tsirigotis, A.; Tsirmpas, J.; Tzamarias, S.; Vasiliev, O.; Vaskine, O.; Voigt, W.; Vougioukas, A.; Voulgaris, G.; Zacharov, L. M.; Zheleznykh, I. M.; Zhukov, A.

    2003-07-01

    The first so-called flo or with 12 detector modules of the NESTOR deep sea high energy muon and neutrino telescope had been deployed successfully this March (2003) together with its electronics system. Since that data the system and the associated environmental monitoring units are operating properly and data

  11. Overdenture dengan Pegangan Telescopic Crown

    Directory of Open Access Journals (Sweden)

    Pambudi Santoso

    2014-06-01

    Full Text Available Kaitan presisi merupakan alat retensi mekanis yang menghubungkan antara satu atau lebih pegangan gigi tiruan, yang bertujuan untuk menambah retensi dan/atau stabilisasi. Kaitan presisi dapat digunakan secara luas pada gigi tiruan cekat, gigi tiruan sebagian lepasan, overdenture, implant untuk retensi overdenture, dan protesa maksilo fasial. Overdenture dengan kaitan presisi dapat membantu dalam pembagian beban kunyah, meminimalkan trauma pada gigi pegangan dan jaringan lunak, meminimalkan resorbsi tulang, dan meningkatkan estetik dan pengucapan suara. Salah satu jenis dari kaitan presisi adalah telescopic crown, terdiri dari 2 macam mahkota, yaitu mahkota primer yang melekat secara permanen pada gigi penyangga, dan mahkota sekunder yang melekat pada gigi tiruan. Tujuan pemaparan kasus ini adalah untuk memberikan informasi tentang rehabilitasi pasien edentulous sebagian rahang atas dengan telescopic crown..  Pasien wanita berusia 45 tahun datang ke klinik prostodonsia RSGM Prof.Soedomo dengan keluhan ingin dibuatkan gigi tiruan. Pasien kehilangan gigi 11 12 15 16 17 21 22 24 25 26 dan 27 yang diindikasikan untuk pembuatan overdenture gigi tiruan sebagian lepasan (GTS kerangka logam dengan pegangan telescopic crown pada gigi 13 dan 14 dengan sistem parallel-sided crown. Tahap-tahap pembuatan telescopic crown yaitu mencetak model study dengan catatan gigit pendahuluan. Perawatan saluran dilakukan pada akar gigi 13, dilanjutkan pemasangan pasak fiber serta rewalling dinding bukal. Gigi 13 dan 14 dilakukan preparasi mahkota penuh, dilanjutkan dengan pencetakan model kerja untuk coping primer dan kerangka logam dengan metode double impression. Coping primer disementasi pada gigi penyangga, dilanjutkan pasang coba coping sekunder beserta kerangka logam. Selanjutnya dilakukan pencatatan gigit, pencetakan model kerja, penyusunan gigi dan pasang coba penyusunan gigi pada pasien. Prosedur dilanjutkan dengan proses di laboratorium, serta insersi pada

  12. The automated Palomar 60 inch telescope

    OpenAIRE

    Cenko, S Bradley; Fox, Derek B.; Moon, Dae-Sik; Harrison, Fiona A.; Kulkarni, S.R.; Henning, John R.; Guzman, C. Dani; Bonati, Marco; Smith, Roger M.; Thicksten, Robert P.; Doyle, Michael W.; Petrie, Hal L.; Gal-Yam, Avishay; Soderberg, Alicia M.; Anagnostou, Nathaniel L.

    2006-01-01

    We have converted the Palomar 60-inch telescope (P60) from a classical night assistant-operated telescope to a fully robotic facility. The automated system, which has been operational since September 2004, is designed for moderately fast (t

  13. Alignment of the James Webb Space Telescope optical telescope element

    Science.gov (United States)

    Glassman, Tiffany; Levi, Joshua; Liepmann, Till; Hahn, Walter; Bisson, Gary; Porpora, Dan; Hadjimichael, Theo

    2016-07-01

    The optical telescope element (OTE) of the James Webb Space Telescope has now been integrated and aligned. The OTE comprises the flight mirrors and the structure that supports them - 18 primary mirror segments, the secondary mirror, and the tertiary and fine steering mirrors (both housed in the aft optics subsystem). The primary mirror segments and the secondary mirror have actuators to actively control their positions during operations. This allows the requirements for aligning the OTE subsystems to be in the range of microns rather than nanometers. During OTE integration, the alignment of the major subsystems of the OTE structure and optics were controlled to ensure that, when the telescope is on orbit and at cryogenic temperatures, the active mirrors will be within the adjustment range of the actuators. Though the alignment of this flagship mission was complex and intricate, the key to a successful integration process turned out to be very basic: a clear, concise series of steps employing advanced planning, backup measurements, and cross checks that this multi-organizational team executed with a careful and methodical approach. This approach was not only critical to our own success but has implications for future space observatories.

  14. Origins Space Telescope: Telescope Design and Instrument Specifications

    Science.gov (United States)

    Meixner, Margaret; Carter, Ruth; Leisawitz, David; Dipirro, Mike; Flores, Anel; Staguhn, Johannes; Kellog, James; Roellig, Thomas L.; Melnick, Gary J.; Bradford, Charles; Wright, Edward L.; Zmuidzinas, Jonas; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies of NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey. The renaming of the mission reflects Origins science goals that will discover and characterize the most distant galaxies, nearby galaxies and the Milky Way, exoplanets, and the outer reaches of our Solar system. This poster will show the preliminary telescope design that will be a large aperture (>8 m in diameter), cryogenically cooled telescope. We will also present the specifications for the spectrographs and imagers over a potential wavelength range of ~10 microns to 1 millimeter. We look forward to community input into this mission definition over the coming year as we work on the concept design for the mission. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. We welcome you to contact the Science and Technology Definition Team (STDT) with your science needs and ideas by emailing us at firsurveyor_info@lists.ipac.caltech.edu.

  15. The Medium Size Telescopes of the Cherenkov Telescope Array

    CERN Document Server

    Pühlhofer, G

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the planned next-generation instrument for ground-based gamma-ray astronomy, covering a photon energy range of ~20 GeV to above 100 TeV. CTA will consist of the order of 100 telescopes of three sizes, installed at two sites in the Northern and Southern Hemisphere. This contribution deals with the 12 meter Medium Size Telescopes (MST) having a single mirror (modified Davies-Cotton, DC) design. In the baseline design of the CTA arrays, 25 MSTs in the South and 15 MSTs in the North provide the necessary sensitivity for CTA in the core energy range of 100 GeV to 10 TeV. DC-MSTs will be equipped with photomultiplier (PMT)-based cameras. Two options are available for these focal plane instruments, that will be provided by the FlashCam and the NectarCAM sub-consortia. In this contribution, a short introduction to the projects and their status is given.

  16. The Principles of Astronomical Telescope Design

    CERN Document Server

    Cheng, Jingquan

    2009-01-01

    Presents a summary of the author's twenty five years of experience in telescope design. This work provides a general introduction to various aspects of telescope design. It discusses the theory behind telescope design. It covers Radio, Infrared, Optical, X-Ray and Gamma-Ray wavelengths

  17. The Hubble Space Telescope: Problems and Solutions.

    Science.gov (United States)

    Villard, Ray

    1990-01-01

    Presented is the best understanding of the flaw discovered in the optics of the Hubble Space Telescope and the possible solutions to the problems. The spherical aberration in the telescope's mirror and its effect on the quality of the telescope's imaging ability is discussed. (CW)

  18. CFRP lightweight structures for extremely large telescopes

    DEFF Research Database (Denmark)

    Jessen, Niels Christian; Nørgaard-Nielsen, Hans Ulrik; Schroll, J.

    2008-01-01

    Telescope structures are traditionally built out of steel. To improve the possibility of realizing the ambitious extremely large telescopes, materials with a higher specific stiffness and a lower coefficient of thermal expansion are needed. An important possibility is Carbon Fibre Reinforced...... Plastic (CFRP). The advantages of using CFRP for the secondary mirror support structure of the European overwhelmingly large telescope are discussed....

  19. Focusing X-Ray Telescopes

    Science.gov (United States)

    O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; Juda, Michael; Kolodziejczak, Jeffrey; Murray, Stephen; Petre, Robert; Podgorski, William; Ramsey, Brian; Reid, Paul; Saha, Timo; Wolk, Scott; Troller-McKinstry, Susan; Weisskopf, Martin; Wilke, Rudeger; Zhang, William

    2010-01-01

    During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

  20. The Ortega Telescope Andor CCD

    Science.gov (United States)

    Tucker, M.; Batcheldor, D.

    2012-07-01

    We present a preliminary instrument report for an Andor iKon-L 936 charge-couple device (CCD) being operated at Florida Tech's 0.8 m Ortega Telescope. This camera will replace the current Finger Lakes Instrumentation (FLI) Proline CCD. Details of the custom mount produced for this camera are presented, as is a quantitative and qualitative comparison of the new and old cameras. We find that the Andor camera has 50 times less noise than the FLI, has no significant dark current over 30 seconds, and has a smooth, regular flat field. The Andor camera will provide significantly better sensitivity for direct imaging programs and, once it can be satisfactorily tested on-sky, will become the standard imaging device on the Ortega Telescope.

  1. Telescoping phenomenon in pathological gambling

    DEFF Research Database (Denmark)

    Grant, Jon E; Odlaug, Brian Lawrence; Mooney, Marc E

    2012-01-01

    The course of pathological gambling (PG) in women has been described as having a later age of initiation but a shorter time to problematic gambling ("telescoped"). This study examined evidence for telescoping and its relationship with comorbidities. Seventy-one treatment-seeking individuals with PG...... underwent a diagnostic interview to examine gambling behaviors, age at initiation of gambling, and time from initiation to meeting criteria for PG. The women had a higher mean age at gambling initiation compared with that of the men (mean [SD] age, 31.3 [13.0] years, compared with 22.4 [7.9] years; p = 0...... and suggests a need for greater clinical focus on the gender differences of gambling behavior....

  2. Cherenkov Telescope Array Data Management

    CERN Document Server

    Lamanna, G; Contreras, J L; Knödlseder, J; Kosack, K; Neyroud, N; Aboudan, A; Arrabito, L; Barbier, C; Bastieri, D; Boisson, C; Brau-Nogué, S; Bregeon, J; Bulgarelli, A; Carosi, A; Costa, A; De Cesare, G; Reyes, R de los; Fioretti, V; Gallozzi, S; Jacquemier, J; Khelifi, B; Kocot, J; Lombardi, S; Lucarelli, F; Lyard, E; Maier, G; Massimino, P; Osborne, J P; Perri, M; Rico, J; Sanchez, D A; Satalecka, K; Siejkowski, H; Stolarczyk, T; Szepieniec, T; Testa, V; Walter, R; Ward, J E; Zoli, A

    2015-01-01

    Very High Energy gamma-ray astronomy with the Cherenkov Telescope Array (CTA) is evolving towards the model of a public observatory. Handling, processing and archiving the large amount of data generated by the CTA instruments and delivering scientific products are some of the challenges in designing the CTA Data Management. The participation of scientists from within CTA Consortium and from the greater worldwide scientific community necessitates a sophisticated scientific analysis system capable of providing unified and efficient user access to data, software and computing resources. Data Management is designed to respond to three main issues: (i) the treatment and flow of data from remote telescopes; (ii) "big-data" archiving and processing; (iii) and open data access. In this communication the overall technical design of the CTA Data Management, current major developments and prototypes are presented.

  3. Highlights from the Telescope Array

    Directory of Open Access Journals (Sweden)

    Matthews J.N.

    2016-01-01

    Full Text Available The Telescope Array measures the properties of ultra high energy cosmic ray induced extensive air showers. We do this using a variety of techniques including an array of scintillator detectors to sample the footprint of the air shower when it reaches the Earth’s surface and telescopes to measure the fluorescence and Cerenkov light of the air shower. From this we determine the energy spectrum and chemical composition of the primary particles. We also search for sources of cosmic rays and anisotropy. We have found evidence of a possible source of ultra high energy cosmic rays in the northern sky. The experiment and its most recent measurements will be discussed.

  4. The LWA1 Radio Telescope

    CERN Document Server

    Ellingson, S W; Craig, J; Hartman, J; Dowell, J; Wolfe, C N; Clarke, T E; Hicks, B C; Kassim, N E; Ray, P S; Rickard, L J; Schinzel, F K; Weiler, K W

    2012-01-01

    LWA1 is a new radio telescope operating in the frequency range 10-88 MHz, located in central New Mexico. The telescope consists of 258 pairs of dipole-type antennas whose outputs are individually digitized and formed into beams. Simultaneously, signals from all dipoles can be recorded using one of the instrument's "all dipoles" modes, facilitating all-sky imaging. Notable features of the instrument include high intrinsic sensitivity (about 6 kJy zenith system equivalent flux density), large instantaneous bandwidth (up to 78 MHz), and 4 independently-steerable beams utilizing digital "true time delay" beamforming. This paper summarizes the design of LWA1 and its performance as determined in commissioning experiments. We describe the method currently in use for array calibration, and report on measurements of sensitivity and beamwidth.

  5. Focusing Telescopes in Nuclear Astrophysics

    CERN Document Server

    Ballmoos, Peter von

    2007-01-01

    This volume is the first of its kind on focusing gamma-ray telescopes. Forty-eight refereed papers provide a comprehensive overview of the scientific potential and technical challenges of this nascent tool for nuclear astrophysics. The book features articles dealing with pivotal technologies such as grazing incident mirrors, multilayer coatings, Laue- and Fresnel-lenses - and even an optic using the curvature of space-time. The volume also presents an overview of detectors matching the ambitious objectives of gamma ray optics, and facilities for operating such systems on the ground and in space. The extraordinary scientific potential of focusing gamma-ray telescopes for the study of the most powerful sources and the most violent events in the Universe is emphasized in a series of introductory articles. Practicing professionals, and students interested in experimental high-energy astrophysics, will find this book a useful reference

  6. Balloon Flight Test of a Compton Telescope Based on Scintillators with Silicon Photomultiplier Readouts

    CERN Document Server

    Bloser, P F; Bancroft, C M; Ryan, J M; McConnell, M L

    2016-01-01

    We present the results of the first high-altitude balloon flight test of a concept for an advanced Compton telescope making use of modern scintillator materials with silicon photomultiplier (SiPM) readouts. There is a need in the fields of high-energy astronomy and solar physics for new medium-energy gamma-ray (~0.4 - 10 MeV) detectors capable of making sensitive observations. A fast scintillator- based Compton telescope with SiPM readouts is a promising solution to this instrumentation challenge, since the fast response of the scintillators permits the rejection of background via time-of-flight (ToF) discrimination. The Solar Compton Telescope (SolCompT) prototype was designed to demonstrate stable performance of this technology under balloon-flight conditions. The SolCompT instrument was a simple two-element Compton telescope, consisting of an approximately one-inch cylindrical stilbene crystal for a scattering detector and a one-inch cubic LaBr3:Ce crystal for a calorimeter detector. Both scintillator dete...

  7. The James Webb Space Telescope

    Science.gov (United States)

    Gardner, Jonathan P.

    2011-01-01

    The James Webb Space Telescope is the scientific successor to the Hubble and Spitzer Space Telescopes, and is currently the largest scientific project under construction in the United States. It will be a large (6.6m) cold (50K) telescope launched into orbit around the second Earth-Sun Lagrange point. It is a partnership of NASA with the European and Canadian Space Agencies. Science with the James Webb Space Telescope falls into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. Webb will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. I will conclude the talk with a description of recent technical progress in the construction of the observatory.

  8. The Antares Undersea Neutrino Telescope

    Science.gov (United States)

    Anghinolfi, Marco

    2013-11-01

    Neutrino astronomy is a very promising field of investigation representing a complementary source of information with respect to photon-astronomy. ANTARES, operating off the French Mediterranean coast, is the worlds largest operational underwater neutrino telescope. In these proceedings, in addition to a short detector description, the results of recent analysis will be discussed. The ANTARES project is an important physics experiment but also represents a bench mark for a future large detector of the km3 scale.

  9. An investigation of the standard of classification of retinal hemorrhage in full-term normal delivery newborns ;according to digital wide-angle retinal imaging device RetCam-3%Retcam-3检查足月新生儿视网膜出血分级的初步探讨

    Institute of Scientific and Technical Information of China (English)

    王雅丛; 耿韶辉; 李艳涛; 王玉芳; 张红; 张婷婷; 张佳佳; 张炜

    2015-01-01

    Objective To probe the classification of retinal hemorrhage(RH)in vaginal delivery term newborns accord-ing to digital wide-angle retinal imaging device(RetCam-3 ).Methods A total of 1 021 healthy full-term normal delivery newborns(2 042 eyes)were enrolled in this study.A digital wide-angle retinal imaging device(RetCam m)was used to examine the subjects at about 3 days after birth.Newborns with RH were reexamined after three,four and six weeks.RH was classified according to the location of RH and degree of hemorrhage in macular by RetCam-3.Results In 1 021 cases of newborns,retinal hemorrhages were found in 165 infants(17.14%).Within these 165 infants,155 infants(16.16%)wereⅠdegree retinal hemorrhage,9 infants(0.88%)were Ⅱdegree retinal hemorrhage and 1 infant (0.01%)was Ⅲ degree retinal hemorrhage.The average time of second stage of labor in newborns without RH was 49.81 ±5.3 minites.The average time of second stage of labor in newborns with RH was 51.13 ±6.12 minutes.New-borns with RH had longer second stage of labor than those without RH.The difference was statistically significant (t =2.839,P =0.005).Conclusion According to the result of RetCam-3 of 2 042 eyes,we classify RH in degreeⅠ,Ⅱand Ⅲ.RH of DegreeⅠis located in the superficial retina and resolves itself within three weeks after birth.RH of DegreeⅡ is located in the superficial retina including macular and resolves itself within six weeks after birth.RH of De-gree Ⅲ is located ahead of retina including macular and does not resolve itself within six weeks after birth.Prolonged second stage of labor may play roles of risk factor in retinal hemorrhage.%目的:采用广域数码视网膜成像系统(Retcam-3)探讨足月新生儿视网膜出血的分级方法。方法对1021例顺产足月新生儿(2042眼)出生3 d 内进行 Retcam-3眼底照相,初次检查发现视网膜出血者分别于3、4、6周后复查眼底。根据视网膜出血位置和黄斑出血程度对视

  10. Building the Green Bank Telescope

    Science.gov (United States)

    Kellermann, Kenneth I.

    2017-01-01

    In a previous presentation, I reported on how the freak collapse of the NRAO 300-ft transit radio telescope led to the inclusion of $75 million for a new radio telescope in the 1989 Congressional Emergency Supplemental Appropriations Act. But, this was only the beginning. NRAO was faced with challenging specifications and an unworkable schedule, but there was no design and no project team. Only one bid was even close to the Congressional appropriation. In an attempt to meet the unrealistic antenna delivery date, the contractor started construction of the foundation and fabrication of antenna members before the design was finished, leading to retrofits, redesign, and multiple delays. The antenna contractor was twice sold to other companies leading to further delays and cost escalation. In order to recoup their mounting losses, the new owners sued NRAO for $29 million for claimed design changes, and NRAO countersued demanding to be reimbursed for added project management costs and lost scientific data resulting from the seven-year delay in the completion of the telescope. Legal fees and a small net award in favor of the contractor left NRAO and the NSF with a nine million dollar bill which NSF handled by an innovative accounting adjustment.

  11. Academic Training: Deep Space Telescopes

    CERN Multimedia

    Françoise Benz

    2006-01-01

    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 20, 21, 22, 23, 24 February from 11:00 to 12:00 - Council Chamber on 20, 21, 23, 24 February, TH Auditorium, bldg 4 - 3-006, on 22 February Deep Space Telescopes G. BIGNAMI / CNRS, Toulouse, F & Univ. di Pavia, I The short series of seminars will address results and aims of current and future space astrophysics as the cultural framework for the development of deep space telescopes. It will then present such new tools, as they are currently available to, or imagined by, the scientific community, in the context of the science plans of ESA and of all major world space agencies. Ground-based astronomy, in the 400 years since Galileo's telescope, has given us a profound phenomenological comprehension of our Universe, but has traditionally been limited to the narrow band(s) to which our terrestrial atmosphere is transparent. Celestial objects, however, do not care about our limitations, and distribute most of the information about their physics thro...

  12. The NASA Spitzer Space Telescope.

    Science.gov (United States)

    Gehrz, R D; Roellig, T L; Werner, M W; Fazio, G G; Houck, J R; Low, F J; Rieke, G H; Soifer, B T; Levine, D A; Romana, E A

    2007-01-01

    The National Aeronautics and Space Administration's Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991-2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer's expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/.

  13. QUIJOTE telescope design and fabrication

    Science.gov (United States)

    Gomez, Alberto; Murga, Gaizka; Etxeita, Borja; Sanquirce, Rubén; Rebolo, Rafael; Rubiño-Martin, Jose Alberto; Herreros, José-Miguel; Hoyland, Roger; Gomez, Francisca; Génova-Santos, Ricardo T.; Piccirillo, Lucio; Maffei, Bruno; Watson, Robert

    2010-07-01

    The QUIJOTE CMB experiment aims to characterize the polarization of the CMB in the frequency range 10-30 GHz and large angular scales. It will be installed in the Teide Observatory, following the projects that the Anisotropy of the Cosmic Microwave Background group has developed in the past (Tenerife experiment, IAC-Bartol experiment...) and is running at the present time (VSA, Cosmosomas). The QUIJOTE CMB experiment will consist of two telescopes which will be installed inside a unique enclosure, which is already constructed. The layout of both telescopes is based on an altazimuth mount supporting a primary and a secondary mirror disposed in a offset Gregorian Dragon scheme. The use of industrial-like fabrication techniques, such as sand-mould casting, CNC machining, and laser tracker measuring for alignment, provided the required performances for microwave observation. A fast-track construction scheme, altogether with the use of these fabrication techniques allowed designing and manufacturing the opto-mechanics of the telescope in 14 months prior to delivery for final start-up in December 2008.

  14. Telescope Alignment From Sparsely Sampled Wavefront Measurements Over Pupil Subapertures

    Science.gov (United States)

    Bloemhof, Eric E.; An, Xin; Kuan, Gary M.; Moore, Douglas M.; OShay, Joseph F.; Tang, Hong; Page, Norman A.

    2012-01-01

    Alignment of two-element telescopes is a classic problem. During recent integration and test of the Space Interferometry Mission s (SIM s) Astrometric Beam Combiner (ABC), the innovators were faced with aligning two such telescope subsystems in the presence of a further complication: only two small subapertures in each telescope s pupil were accessible for measuring the wavefront with a Fizeau interferometer. This meant that the familiar aberrations that might be interpreted to infer system misalignments could be viewed only over small sub-regions of the pupil, making them hard to recognize. Further, there was no contiguous surface of the pupil connecting these two subapertures, so relative phase piston information was lost; the underlying full-aperture aberrations therefore had an additional degree of ambiguity. The solution presented here is to recognize that, in the absence of phase piston, the Zygo measurements primarily provide phase tilt in the subaperture windows of interest. Because these windows are small and situated far from the center of the (inaccessible) unobscured full aperture, any aberrations that are higher-order than tilt will be extremely high-order on the full aperture, and so not necessary or helpful to the alignment. Knowledge of the telescope s optical prescription allows straightforward evaluation of sensitivities (subap mode strength per unit full-aperture aberration), and these can be used in a predictive matrix approach to move with assurance to an aligned state. The technique is novel in every operational way compared to the standard approach of alignment based on full-aperture aberrations or searching for best rms wavefront. This approach is closely grounded in the observable quantities most appropriate to the problem. It is also more intuitive than inverting full phase maps (or subaperture Zernike spectra) with a ray-tracing program, which must certainly work in principle, but in practice met with limited success. Even if such

  15. Hard X-ray Modulation Telescope

    Institute of Scientific and Technical Information of China (English)

    LU Fangjun

    2011-01-01

    The Hard X-ray Modulation Telescope (HXMT) will be China's first astronomical satellite. On board HXMT there are three kinds of slat-collimated telescopes, the High Energy X-ray Telescope (HE, 20-250 keV, 5000 cm^2), the Medium Energy X-ray Telescope (ME, 5-30 keV, 952 cm^2), and the Low Energy X-ray Telescope (LE, 1-15 keV, 384 cm^2).

  16. Educational activities with the Faulkes Telescopes

    Science.gov (United States)

    Roberts, S.; Roche, P.; Ross, R.

    2008-06-01

    Las Cumbres Observatory Global Telescope Network (LCOGTN) will eventually provide access to a global network of robotic telescopes for research-based science education. Here we present the educational projects that have been undertaken using the 2-m Faulkes Telescopes in Hawaii and Australia in both the UK and Europe. These include themed observing days in which schools collaborate in their telescope sessions, the development of science portals where schools can upload and share their telescope data, and other innovative projects. Public access to these facilities will increase as IYA2009 approaches.

  17. The search for optical emission on and before the GRB trigger with the WIDGET telescope

    CERN Document Server

    Tamagawa, T; Urata, Y; Abe, K; Onda, K; Tashiro, M; Terada, Y; Fujiwara, H; Miura, N; Hirose, S; Kawai, N; Yoshida, A; Mori, M; Makishima, K

    2005-01-01

    WIDGET is a robotic telescope for monitoring the HETE-2 field-of-view to detect Gamma-ray Burst optical flashes or possible optical precursors. The system has 62degx62deg wide field-of-view which covers about 80% of HETE-2 one with a 2kx2k Apogee U10 CCD camera and a Canon EF 24mm f/1.4 wide-angle lens without a bandpass filter. WIDGET has been in operation since June 2004 at Akeno observing site where is about 200 km apart from Tokyo. Typical limiting magnitude with S/N=3 at the site is V=10mag for 5 seconds exposure and V=11mag for 30 seconds exposure. We had already six coincident observations with HETE-2 position alerts. It was, however, cloudy for all cases due to rainy season in Japan. Expected number of coincident observations under clear sky is about 5 events per year. We will extend the system in early 2005 for Swift era to monitor optical transients in wider field-of-view, multi-color or polarization modes.

  18. Hubble Space Telescope: The Telescope, the Observations & the Servicing Mission

    Science.gov (United States)

    1999-11-01

    Today the HST Archives contain more than 260 000 astronomical observations. More than 13 000 astronomical objects have been observed by hundreds of different groups of scientists. Direct proof of the scientific significance of this project is the record-breaking number of papers published : over 2400 to date. Some of HST's most memorable achievements are: * the discovery of myriads of very faint galaxies in the early Universe, * unprecedented, accurate measurements of distances to the farthest galaxies, * significant improvement in the determination of the Hubble constant and thus the age of the Universe, * confirmation of the existence of blacks holes, * a far better understanding of the birth, life and death of stars, * a very detailed look at the secrets of the process by which planets are created. Europe and HST ESA's contribution to HST represents a nominal investment of 15%. ESA provided one of the two imaging instruments - the Faint Object Camera (FOC) - and the solar panels. It also has 15 scientists and computer staff working at the Space Telescope Science Institute in Baltimore (Maryland). In Europe the astronomical community receives observational assistance from the Space Telescope European Coordinating Facility (ST-ECF) located in Garching, Munich. In return for ESA's investment, European astronomers have access to approximately 15% of the observing time. In reality the actual observing time competitively allocated to European astronomers is closer to 20%. Looking back at almost ten years of operation, the head of ST-ECF, European HST Project Scientist Piero Benvenuti states: "Hubble has been of paramount importance to European astronomy, much more than the mere 20% of observing time. It has given the opportunity for European scientists to use a top class instrument that Europe alone would not be able to build and operate. In specific areas of research they have now, mainly due to HST, achieved international leadership." One of the major reasons for

  19. Herschel SPIRE FTS telescope model correction

    CERN Document Server

    Hopwood, Rosalind; Polehampton, Edward T; Valtchanov, Ivan; Benielli, Dominique; Imhof, Peter; Lim, Tanya; Lu, Nanyao; Marchili, Nicola; Pearson, Chris P; Swinyard, Bruce M

    2014-01-01

    Emission from the Herschel telescope is the dominant source of radiation for the majority of SPIRE Fourier transform spectrometer (FTS) observations, despite the exceptionally low emissivity of the primary and secondary mirrors. Accurate modelling and removal of the telescope contribution is, therefore, an important and challenging aspect of FTS calibration and data reduction pipeline. A dust-contaminated telescope model with time invariant mirror emissivity was adopted before the Herschel launch. However, measured FTS spectra show a clear evolution of the telescope contribution over the mission and strong need for a correction to the standard telescope model in order to reduce residual background (of up to 7 Jy) in the final data products. Systematic changes in observations of dark sky, taken over the course of the mission, provide a measure of the evolution between observed telescope emission and the telescope model. These dark sky observations have been used to derive a time dependent correction to the tel...

  20. Aligning Astronomical Telescopes via Identification of Stars

    Science.gov (United States)

    Whorton, Mark

    2010-01-01

    A proposed method of automated, precise alignment of a ground-based astronomical telescope would eliminate the need for initial manual alignment. The method, based on automated identification of known stars and other celestial objects in the telescope field of view, would also eliminate the need for an initial estimate of the aiming direction. The method does not require any equipment other than a digital imaging device such as a charge-coupled-device digital imaging camera and control computers of the telescope and camera, all of which are standard components in professional astronomical telescope systems and in high-end amateur astronomical telescope systems. The method could be implemented in software running in the telescope or camera control computer or in an external computer communicating with the telescope pointing mount and camera control computers.

  1. Status of the Cherenkov Telescope Array's Large Size Telescopes

    CERN Document Server

    Cortina, J

    2015-01-01

    The Cherenkov Telescope Array (CTA) observatory, will be deployed over two sites in the two hemispheres. Both sites will be equipped with four Large Size Telescopes (LSTs), which are crucial to achieve the science goals of CTA in the 20-200 GeV energy range. Each LST is equipped with a primary tessellated mirror dish of 23 m diameter, supported by a structure made mainly of carbon fibre reinforced plastic tubes and aluminum joints. This solution guarantees light weight (around 100 tons), essential for fast repositioning to any position in the sky in <20 seconds. The camera is composed of 1855 PMTs and embeds the control, readout and trigger electronics. The detailed design is now complete and production of the first LST, which will serve as a prototype for the remaining seven, is well underway. In 2016 the first LST will be installed at the Roque de los Muchachos Observatory on the Canary island of La Palma (Spain). In this talk we will outline the technical solutions adopted to fulfill the design requirem...

  2. Scientific Potential of Einstein Telescope

    CERN Document Server

    Sathyaprakash, B; Acernese, F; Andersson, P Amaro-Seoane N; Arun, K; Barone, F; Barr, B; Barsuglia, M; Beveridge, M Beker N; Birindelli, S; Bose, S; Bosi, L; Braccini, S; Bradaschia, C; Bulik, T; Calloni, E; Cella, G; Mottin, E Chassande; Chelkowski, S; Chincarini, A; Clark, J; Coccia, E; Colacino, C; Colas, J; Cumming, A; Cunningham, L; Cuoco, E; Danilishin, S; Danzmann, K; Salvo, R De; Dent, T; Rosa, R De; Fiore, L Di; Virgilio, A Di; Doets, M; Fafone, V; Falferi, P; Flaminio, R; Franc, J; Frasconi, F; Freise, A; Friedrich, D; Fulda, P; Gair, J; Gemme, G; Genin, E; Gennai, A; Giazotto, A; Glampedakis, K; Gräf, C; Granata, M; Grote, H; Guidi, G; Gurkovsky, A; Hammond, G; Hannam, M; Harms, J; Heinert, D; Hendry, M; Heng, I; Hennes, E; Hild, S; Hough, J; Husa, S; Huttner, S; Jones, G; Khalili, F; Kokeyama, K; Kokkotas, K; Krishnan, B; Li, T G F; Lorenzini, M; Lück, H; Majorana, E; Mandel, I; Mandic, V; Mantovani, M; Martin, I; Michel, C; Minenkov, Y; Morgado, N; Mosca, S; Mours, B; Müller--Ebhardt, H; Murray, P; Nawrodt, R; Nelson, J; Oshaughnessy, R; Ott, C D; Palomba, C; Paoli, A; Parguez, G; Pasqualetti, A; Passaquieti, R; Passuello, D; Pinard, L; Plastino, W; Poggiani, R; Popolizio, P; Prato, M; Punturo, M; Puppo, P; Rabeling, D; Racz, I; Rapagnani, P; Read, J; Regimbau, T; Rehbein, H; Reid, S; Rezzolla, L; Ricci, F; Richard, F; Rocchi, A; Rowan, S; Rüdiger, A; Santamaría, L; Sassolas, B; Schnabe, R; Schwarz, C; Seidel, P; Sintes, A; Somiya, K; Speirits, F; Strain, K; Strigin, S; Sutton, P; Tarabrin, S; Thüring, A; Brand, J van den; Veggel, M van; Broeck, C van den; Vecchio, A; Veitch, J; Vetrano, F; Vicere, A; Vyatchanin, S; Willke, B; Woan, G; Yamamoto, K

    2011-01-01

    Einstein gravitational-wave Telescope (ET) is a design study funded by the European Commission to explore the technological challenges of and scientific benefits from building a third generation gravitational wave detector. The three-year study, which concluded earlier this year, has formulated the conceptual design of an observatory that can support the implementation of new technology for the next two to three decades. The goal of this talk is to introduce the audience to the overall aims and objectives of the project and to enumerate ET's potential to influence our understanding of fundamental physics, astrophysics and cosmology.

  3. Detectors for the space telescope

    Science.gov (United States)

    Kelsall, T.

    1978-01-01

    This review of Space Telescope (ST) detectors is divided into two parts. The first part gives short summaries of detector programs carried out during the final planning stage (Phase B) of the ST and discusses such detectors as Photicon, the MAMA detectors, the CODACON, the University of Maryland ICCD, the Goddard Space Flight Center ICCD, and the 70 mm SEC TV sensor. The second part describes the detectors selected for the first ST flight, including the wide field/planetary camera, the faint object and high resolution spectrographs, and the high speed photometer.

  4. Cosmography with the Einstein Telescope

    CERN Document Server

    Sathyaprakash, B S; Broeck, Chris Van Den

    2009-01-01

    Einstein Telescope (ET) is a 3rd generation gravitational-wave (GW) detector that is currently undergoing a design study. ET can detect millions of compact binary mergers up to redshifts 2-8. A small fraction of mergers might be observed in coincidence as gamma-ray bursts, helping to measure both the luminosity distance and red-shift to the source. By fitting these measured values to a cosmological model, it should be possible to accurately infer the dark energy equation-of-state, dark matter and dark energy density parameters. ET could, therefore, herald a new era in cosmology.

  5. The Advanced Compton Telescope Mission

    CERN Document Server

    Boggs, S E; Ryan, J; Aprile, E; Gehrels, N; Kippen, M; Leising, M; Oberlack, U; Wunderer, C; Zych, A; Bloser, P; Harris, M; Hoover, A; Klimenk, A; Kocevski, D; McConnell, M; Milne, P; Novikova, E I; Phlips, B; Polsen, M; Sturner, S; Tournear, D; Weidenspointner, G; Wulf, E; Zoglauer, A; Baring, M; Beacom, J; Bildsten, L; Dermer, C; Hartmann, D; Hernanz, M; Smith, D; Starrfield, S; Boggs, Steven E.; Kurfess, James; Ryan, James; Aprile, Elena; Gehrels, Neil; Kippen, Marc; Leising, Mark; Oberlack, Uwe; Wunderer, Cornelia; Zych, Allen; Bloser, Peter; Harris, Michael; Hoover, Andrew; Klimenk, Alexei; Kocevski, Dan; Connell, Mark Mc; Milne, Peter; Novikova, Elena I.; Phlips, Bernard; Polsen, Mark; Sturner, Steven; Tournear, Derek; Weidenspointner, Georg; Wulf, Eric; Zoglauer, Andreas; Baring, Matthew; Beacom, John; Bildsten, Lars; Dermer, Charles; Hartmann, Dieter; Hernanz, Margarita; Smith, David; Starrfield, Sumner

    2006-01-01

    The Advanced Compton Telescope (ACT), the next major step in gamma-ray astronomy, will probe the fires where chemical elements are formed by enabling high-resolution spectroscopy of nuclear emission from supernova explosions. During the past two years, our collaboration has been undertaking a NASA mission concept study for ACT. This study was designed to (1) transform the key scientific objectives into specific instrument requirements, (2) to identify the most promising technologies to meet those requirements, and (3) to design a viable mission concept for this instrument. We present the results of this study, including scientific goals and expected performance, mission design, and technology recommendations.

  6. ALMA telescope reaches new heights

    Science.gov (United States)

    2009-09-01

    of the Array Operations Site. This means surviving strong winds and temperatures between +20 and -20 Celsius whilst being able to point precisely enough that they could pick out a golf ball at a distance of 15 km, and to keep their smooth reflecting surfaces accurate to better than 25 micrometres (less than the typical thickness of a human hair). Once the transporter reached the high plateau it carried the antenna to a concrete pad - a docking station with connections for power and fibre optics - and positioned it with an accuracy of a few millimetres. The transporter is guided by a laser steering system and, just like some cars today, also has ultrasonic collision detectors. These sensors ensure the safety of the state-of-the-art antennas as the transporter drives them across what will soon be a rather crowded plateau. Ultimately, ALMA will have at least 66 antennas distributed over about 200 pads, spread over distances of up to 18.5 km and operating as a single, giant telescope. Even when ALMA is fully operational, the transporters will be used to move the antennas between pads to reconfigure the telescope for different kinds of observations. "Transporting our first antenna to the Chajnantor plateau is a epic feat which exemplifies the exciting times in which ALMA is living. Day after day, our global collaboration brings us closer to the birth of the most ambitious ground-based astronomical observatory in the world", said Thijs de Graauw, ALMA Director. This first ALMA antenna at the high site will soon be joined by others and the ALMA team looks forward to making their first observations from the Chajnantor plateau. They plan to link three antennas by early 2010, and to make the first scientific observations with ALMA in the second half of 2011. ALMA will help astronomers answer important questions about our cosmic origins. The telescope will observe the Universe using light with millimetre and submillimetre wavelengths, between infrared light and radio waves in

  7. Corrector systems for cassegrain telescopes.

    Science.gov (United States)

    Wilson, R N

    1968-02-01

    Most modern reflecting telescopes have relative apertures of about f/3 and f/8 for the primary and first secondary foci in accordance with the suggestions of Bowen. The angular field which can be used at the first secondary focus is limited by the size of available plates for large instruments but can approach +/-1 degrees for smaller systems. The factors influencing the choice of the field corrector system in the first secondary focus are discussed. It is an important point whether the Ritchey-Chrétien form of the mirrors is strictly maintained-giving an optimum field without the corrector-or whether the aspheric constants are allowed to vary as free parameters. The differences are small but significant. The performance of a number of secondary focus correctors consisting of one, two, and three elements is discussed, spot diagrams being given in each case. Systems with fixed Ritchey-Chrétien mirror constants are inferior to those with free mirror constants. Test methods for the manufacture of the mirrors of telescopes of this type are compared. A doublet type corrector is suitable for compensation testing of primary mirrors or for secondaries tested from the back, but the testing of the latter from the front is more difficult. Several possible techniques are discussed.

  8. Origins Space Telescope: Community Participation

    Science.gov (United States)

    Carey, Sean J.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its imagers and spectrographs will enable a variety of surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. This poster will outline the ways in which the astronomical community can participate in the STDT activities and a summary of tools that are currently available or are planned for the community during the study. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu.

  9. Far Ultraviolot Space Telescope (FAUST)

    Science.gov (United States)

    Bowyer, S.

    1988-01-01

    The Far Ultraviolet Space Telescope is a compact, wide field-of-view, far ultraviolet instrument designed for observations of extended and point sources of astronomical interest. It was originally used in sounding rocket work by both French and American investigators. The instrument was modified for flight on the space shuttle and flew on the Spacelab 1 mission as a joint effort between the Laboratoire d'Astronomie Spatiale and the University of California, Berkeley. The prime experiment objective of this telescope on the Atmospheric Laboratory Applications and Science (ATLAS 1) NASA mission is to observe faint astronomical sources in the far ultraviolet with sensitivities far higher than previously available. The experiment will cover the 1300 to 1800 A band, which is inaccessible to observers on earth. The observing program during the mission consists of obtaining deep sky images during spacecraft nighttime. The targets will include hot stars and nebulae in our own galaxy, faint diffuse galactic features similar to the cirrus clouds seen by the Infrared Astronomical Satellite (IRAS), large nearby galaxies, nearby clusters of galaxies, and objects of cosmological interest such as quasars and the diffuse far ultraviolet background.

  10. Origins Space Telescope: Study Plan

    Science.gov (United States)

    Cooray, Asantha R.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its spectrographs will enable 3D surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu. This presentation will provide a summary of the OST STDT, the OST Study Team based at NASA Goddard Space Flight Center, study partners, and the advisory panel to the study. This presentation will also summarize recent activities, including the process used to reach a decision on the mission architecture, the identification of key science drivers, and the key study milestones between 2017 and 2020.

  11. ANTARES: An Undersea Neutrino telescope

    CERN Multimedia

    2002-01-01

    The ANTARES (Astronomy with a Neutrino Telescope and ${Abyss}$ environmental RESearch) deep-sea neutrino telescope is designed to search for neutrinos of astrophysical origin. Neutrinos are unique probes of the high energy universe; being neutral they are not deflected by magnetic fields and interacting weakly they can readily escape from the densest regions of the universe. Potential sources of neutrino are galactic (e.g supernova remnants, micro-quasars) and extra-galactic (e.g active galactic nuclei, gamma-ray bursters). Annihilation of dark matter particles in the Sun or Galactic Centre is another well motivated potential source of extra terrestrial neutrinos. The ANTARES detector is located 40 km off the coast of Toulon (France) at a depth of 2475m in the Mediterranean Sea. Being located in the Northern hemisphere it studies the Southern sky and in particular has the Galactic Centre in its field of view. Since 2006, the detector has operated continuously in a partial configuration. The detector was compl...

  12. Merz telescopes a global heritage worth preserving

    CERN Document Server

    2017-01-01

    This book comprises a fascinating collection of contributions on the Merz telescopes in Italy that collectively offer the first survey on historical large refracting telescopes in the country, drawing on original documents and photographs. It opens with a general introduction on the importance of Merz telescopes in the history of astronomy and analyses of the local and international contexts in which the telescopes were made. After examination of an example of the interaction between the maker and the astronomer in the construction and maintenance of these refractors, the history of the Merz telescopes at the main Italian observatories in the nineteenth century is described in detail. Expert testimony is also provided on how these telescopes were successfully used until the second half of the twentieth century for research purposes, thus proving their excellent optical qualities.

  13. ANTARES: The first undersea neutrino telescope

    Science.gov (United States)

    Ageron, M.; Aguilar, J. A.; Al Samarai, I.; Albert, A.; Ameli, F.; André, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Arnaud, K.; Aslanides, E.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J.-J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Becherini, Y.; Beltramelli, J.; Bersani, A.; Bertin, V.; Beurthey, S.; Biagi, S.; Bigongiari, C.; Billault, M.; Blaes, R.; Bogazzi, C.; de Botton, N.; Bou-Cabo, M.; Boudahef, B.; Bouwhuis, M. C.; Brown, A. M.; Brunner, J.; Busto, J.; Caillat, L.; Calzas, A.; Camarena, F.; Capone, A.; Caponetto, L.; Cârloganu, C.; Carminati, G.; Carmona, E.; Carr, J.; Carton, P. H.; Cassano, B.; Castorina, E.; Cecchini, S.; Ceres, A.; Chaleil, Th.; Charvis, Ph.; Chauchot, P.; Chiarusi, T.; Circella, M.; Compère, C.; Coniglione, R.; Coppolani, X.; Cosquer, A.; Costantini, H.; Cottini, N.; Coyle, P.; Cuneo, S.; Curtil, C.; D'Amato, C.; Damy, G.; van Dantzig, R.; de Bonis, G.; Decock, G.; Decowski, M. P.; Dekeyser, I.; Delagnes, E.; Desages-Ardellier, F.; Deschamps, A.; Destelle, J.-J.; di Maria, F.; Dinkespiler, B.; Distefano, C.; Dominique, J.-L.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drogou, J.-F.; Drouhin, D.; Druillole, F.; Durand, D.; Durand, R.; Eberl, T.; Emanuele, U.; Engelen, J. J.; Ernenwein, J.-P.; Escoffier, S.; Falchini, E.; Favard, S.; Fehr, F.; Feinstein, F.; Ferri, M.; Ferry, S.; Fiorello, C.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J.-L.; Galatá, S.; Galeotti, S.; Gay, P.; Gensolen, F.; Giacomelli, G.; Gojak, C.; Gómez-González, J. P.; Goret, Ph.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Hartmann, B.; Heijboer, A. J.; Heine, E.; Hello, Y.; Henry, S.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; Hogenbirk, J.; Hsu, C. C.; Hubbard, J. R.; Jaquet, M.; Jaspers, M.; de Jong, M.; Jourde, D.; Kadler, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Karg, T.; Karkar, S.; Karolak, M.; Katz, U.; Keller, P.; Kestener, P.; Kok, E.; Kok, H.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Kruijer, A.; Kuch, S.; Kulikovskiy, V.; Lachartre, D.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lahonde-Hamdoun, C.; Lamare, P.; Lambard, G.; Languillat, J.-C.; Larosa, G.; Lavalle, J.; Le Guen, Y.; Le Provost, H.; Levansuu, A.; Lefèvre, D.; Legou, T.; Lelaizant, G.; Lévéque, C.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Lyashuk, V.; Magnier, P.; Mangano, S.; Marcel, A.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Masullo, R.; Mazéas, F.; Mazure, A.; Meli, A.; Melissas, M.; Migneco, E.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Neff, M.; Niess, V.; Nooren, G. J. L.; Oberski, J. E. J.; Olivetto, C.; Palanque-Delabrouille, N.; Palioselitis, D.; Papaleo, R.; Păvălaş, G. E.; Payet, K.; Payre, P.; Peek, H.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Picq, C.; Piret, Y.; Poinsignon, J.; Popa, V.; Pradier, T.; Presani, E.; Prono, G.; Racca, C.; Raia, G.; van Randwijk, J.; Real, D.; Reed, C.; Réthoré, F.; Rewiersma, P.; Riccobene, G.; Richardt, C.; Richter, R.; Ricol, J. S.; Rigaud, V.; Roca, V.; Roensch, K.; Rolin, J.-F.; Rostovtsev, A.; Rottura, A.; Roux, J.; Rujoiu, M.; Ruppi, M.; Russo, G. V.; Salesa, F.; Salomon, K.; Sapienza, P.; Schmitt, F.; Schöck, F.; Schuller, J.-P.; Schüssler, F.; Sciliberto, D.; Shanidze, R.; Shirokov, E.; Simeone, F.; Sottoriva, A.; Spies, A.; Spona, T.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Streeb, K.; Sulak, L.; Taiuti, M.; Tamburini, C.; Tao, C.; Tasca, L.; Terreni, G.; Tezier, D.; Toscano, S.; Urbano, F.; Valdy, P.; Vallage, B.; van Elewyck, V.; Vannoni, G.; Vecchi, M.; Venekamp, G.; Verlaat, B.; Vernin, P.; Virique, E.; de Vries, G.; van Wijk, R.; Wijnker, G.; Wobbe, G.; de Wolf, E.; Yakovenko, Y.; Yepes, H.; Zaborov, D.; Zaccone, H.; Zornoza, J. D.; Zúñiga, J.

    2011-11-01

    The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given.

  14. Parameterized Telescoping Proves Algebraic Independence of Sums

    CERN Document Server

    Schneider, Carsten

    2008-01-01

    Usually creative telescoping is used to derive recurrences for sums. In this article we show that the non-existence of a creative telescoping solution, and more generally, of a parameterized telescoping solution, proves algebraic independence of certain types of sums. Combining this fact with summation-theory shows transcendence of whole classes of sums. Moreover, this result throws new light on the question why, e.g., Zeilberger's algorithm fails to find a recurrence with minimal order.

  15. Resolution studies with the DATURA beam telescope

    CERN Document Server

    Jansen, Hendrik

    2016-01-01

    We present resolution studies carried out with the DATURA beam telescope, which belongs to the family of EUDET-type beam telescopes. The EUDET-type beam telescopes make use of CMOS MIMOSA 26 pixel detectors for particle tracking allowing for precise characterisation of particle sensing devices. A profound understanding of the performance of the beam telescope as a whole is obtained by a detailed characterisation of the sensors themselves. We extract the differential intrinsic resolution as measured in a MIMOSA 26 sensor using an iterative pull method and show various clustersize dependent quantities as the residual distribution, the intra-pixel residual width distribution and the intra-pixel frequency distribution.

  16. Two VLT 8.2-m Unit Telescopes in Action

    Science.gov (United States)

    1999-04-01

    454 pix - 86k] [Normal - JPEG: 800 x 907 pix - 301k] [High-Res - JPEG: 978 x 1109 pix - 282k] Caption to PR Photo 19c/99 : Somewhat further out in space, and right on the border between the southern constellations Hydra and Centaurus lies this knotty spiral galaxy, IC 4248 ; the distance is about 210 million light-years. It was imaged with KUEYEN on March 28, 1999, with the same filters and exposure times as used for Photo 19b/99. The image quality is 0.75 arcsec and the field is 90 x 90 arcsec 2. North is up and East is left. Caption to PR Photo 19d/99 : This is a close-up view of the double galaxy NGC 5090 (right) and NGC 5091 (left), in the southern constellation Centaurus. The first is a typical S0 galaxy with a bright diffuse centre, surrounded by a fainter envelope of stars (not resolved in this picture). However, some of the starlike objects seen in this region may be globular clusters (or dwarf galaxies) in orbit around NGC 5090. The other galaxy is of type Sa (the spiral structure is more developed) and is seen at a steep angle. The three-colour composite is based on frames obtained with KUEYEN on March 29, 1999, with the same filters and exposure times as used for Photo 19b/99. The image quality is 0.7 arcsec and the field is 90 x 90 arcsec 2. North is up and East is left. ( Note inserted on April 26: The original caption text identified the second galaxy as NGC 5090B - this error has now been corrected. ESO PR Photo 19e/99 ESO PR Photo 19e/99 [Preview - JPEG: 400 x 441 pix - 282k] [Normal - JPEG: 800 x 882 pix - 966k] [High-Res - JPEG: 3000 x 3307 pix - 6,4M] Caption to PR Photo 19e/99 : Wide-angle photo of the second 8.2-m VLT Unit Telescope, KUEYEN , obtained on March 10, 1999, with the main mirror and its cell in place at the bottom of the telescope structure. The Test Camera with which the astronomical images above were made, is positioned at the Cassegrain focus, inside this mirror cell. The Paranal Inauguration on March 5, 1999, took place under this

  17. COSMOS Hubble Space Telescope Observations

    CERN Document Server

    Scoville, N Z; Blain, A W; Calzetti, D; Comastri, A; Capak, P; Carilli, C; Carlstrom, J E; Carollo, C M; Colbert, J; Daddi, E; Ellis, Richard S; Elvis, M; Ewald, S P; Fall, M; Franceschini, A; Giavalisco, M; Green, W; Griffiths, R E; Guzzo, L; Hasinger, G; Impey, C; Kneib, J P; Koda, J; Koekemoer, A; Lefèvre, O; Lilly, S; Liu, C T; McCracken, H J; Massey, R; Mellier, Y; Miyazaki, S; Mobasher, B; Mould, J; Norman, C; Réfrégier, A; Renzini, A; Rhodes, J; Rich, M; Sanders, D B; Schiminovich, D; Schinnerer, E; Scodeggio, M; Sheth, K; Shopbell, P L; Taniguchi, Y; Tyson, N; Urry, C M; Van Waerbeke, L; Vettolani, P; White, S D M; Yan, L

    2006-01-01

    The Cosmic Evolution Survey (COSMOS) was initiated with an extensive allocation (590 orbits in Cycles 12-13) using the Hubble Space Telescope (HST) for high resolution imaging. Here we review the characteristics of the HST imaging with the Advanced Camera for Surveys (ACS) and parallel observations with NICMOS and WFPC2. A square field (1.8$\\sq$\\deg) has been imaged with single-orbit ACS I-F814W exposures with 50% completeness for sources 0.5\\arcsec in diameter at I$_{AB} $ = 26.0 mag. The ACS imaging is a key part of the COSMOS survey, providing very high sensitivity and high resolution (0.09\\arcsec FWHM, 0.05\\arcsec pixels) imaging and detecting a million objects. These images yield resolved morphologies for several hundred thousand galaxies. The small HST PSF also provides greatly enhanced sensitivity for weak lensing investigations of the dark matter distribution.

  18. Adaptive Optics for Large Telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, S

    2008-06-27

    The use of adaptive optics was originally conceived by astronomers seeking to correct the blurring of images made with large telescopes due to the effects of atmospheric turbulence. The basic idea is to use a device, a wave front corrector, to adjust the phase of light passing through an optical system, based on some measurement of the spatial variation of the phase transverse to the light propagation direction, using a wave front sensor. Although the original concept was intended for application to astronomical imaging, the technique can be more generally applied. For instance, adaptive optics systems have been used for several decades to correct for aberrations in high-power laser systems. At Lawrence Livermore National Laboratory (LLNL), the world's largest laser system, the National Ignition Facility, uses adaptive optics to correct for aberrations in each of the 192 beams, all of which must be precisely focused on a millimeter scale target in order to perform nuclear physics experiments.

  19. The ANTARES underwater neutrino telescope

    CERN Document Server

    Montaruli, Teresa

    2015-01-01

    ANTARES is the first undersea neutrino telescope. It is in its complete configuration since May 2008 at about 2.5 km below the sea surface close to Marseille. Data from 12 lines are being analyzed and are producing first results. Here we discuss first analysis results for 5 lines and 10 lines, and we also comment on the performance of the full detector. We show that the detector has capabilities for discriminating upgoing neutrino events from the much larger amount of downgoing atmospheric muons and that data and simulation are in good agreement. We then discuss the physics reach of the detector for what concerns point-like source and dark matter searches.

  20. Can Radio Telescopes Find Axions?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    axions. Now scientists Katharine Kelley and Peter Quinn at ICRAR, University of Western Australia, have explored how we might use next-generation radio telescopes to search for photons that were created by axions interacting with the magnetic fields of our galaxy.Hope for Next-Gen TelescopesPotential axion coupling strengths vs. mass (click for a closer look). The axion mass is thought to lie between a eV and a meV; two theoretical models are shown with dashed lines. The plot shows the sensitivity of the upcoming SKA and its precursors, ASKAP and MEERKAT. [KelleyQuinn 2017]By using a simple galactic halo model and reasonable assumptions for the central galactic magnetic field even taking into account the time dependence of the field Kelley and Quinn estimate the radio-frequency power density that we would observe at Earth from axions being converted to photons within the Milky Ways magnetic field.The authors then compare this signature to the detection capabilities of upcoming radio telescope arrays. They show that the upcoming Square Kilometer Array and its precursors should have the capability to detect signs of axions across large parts of parameter space.Kelley and Quinn conclude that theres good cause for optimism about future radio telescopes ability to detect axions. And if we did succeed in making a detection, it would be a triumph for both particle physics and astrophysics, finally providing an explanation for the universes dark matter.CitationKatharine Kelley and P. J. Quinn 2017 ApJL 845 L4. doi:10.3847/2041-8213/aa808d

  1. Recent Results from Telescope Array

    CERN Document Server

    Fukushima, M

    2015-01-01

    The Telescope Array (TA) is an experiment to observe Ultra-High Energy Cosmic Rays (UHECRs). TA's recent results, the energy spectrum and anisotropy based on the 6-year surface array data, and the primary composition obtained from the shower maximum Xmax are reported. The spectrum demonstrates a clear dip and cutoff. The shape of the spectrum is well described by the energy loss of extra-galactic protons interacting with the cosmic microwave background (CMB). Above the cutoff, a medium-scale (20 degrees radius) flux enhancement was observed near the Ursa-Major. A chance probability of creating this hotspot from the isotropic flux is 4.0 sigma. The measured Xmax is consistent with the primary being proton or light nuclei for energies 10^18.2 eV - 10^19.2 eV.

  2. Cosmography with the Einstein Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Sathyaprakash, B S [School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA (United Kingdom); Schutz, B F [Max Planck Institute for Gravitational Physics, The Albert Einstein Institute, Am Muehlenberg 1, Golm, D-14476 (Germany); Van Den Broeck, C, E-mail: B.Sathyaprakash@astro.cf.ac.u, E-mail: B.F.Schutz@aei.mpg.d, E-mail: vdbroeck@nikhef.n [Nikhef - National Institute for Subatomic Physics, Science Park 105, 1098 XG Amsterdam (Netherlands)

    2010-11-07

    The Einstein Telescope, a third-generation gravitational-wave detector under a design study, could detect millions of binary neutron star inspirals each year. A small fraction of these events might be observed as gamma-ray bursts, helping to measure both the luminosity distance D{sub L} to and redshift z of the source. By fitting these measured values of D{sub L} and z to a cosmological model, it would be possible to infer the dark energy equation of state to within 1.5% without the need to correct for errors in D{sub L} caused by weak lensing. This compares favourably with 0.3-10% accuracy that can be achieved with the Laser Interferometer Space Antenna (where weak lensing will need to be dealt with) as well as with dedicated dark energy missions that have been proposed, where 3.5-11% uncertainty is expected.

  3. NESTOR Deep Sea Neutrino Telescope

    Science.gov (United States)

    NESTOR Collaboration; Aggouras, G.; Anassontzis, E. G.; Ball, A. E.; Bourlis, G.; Chinowsky, W.; Fahrun, E.; Grammatikakis, G.; Green, C.; Grieder, P.; Katrivanos, P.; Koske, P.; Leisos, A.; Markopoulos, E.; Minkowsky, P.; Nygren, D.; Papageorgiou, K.; Przybylski, G.; Resvanis, L. K.; Siotis, I.; Sopher, J.; Staveris-Polikalas, A.; Tsagli, V.; Tsirigotis, A.; Tzamarias, S.; Zhukov, V. A.

    2006-01-01

    One module of NESTOR, the Mediterranean deep-sea neutrino telescope, was deployed at a depth of 4000m, 14km off the Sapienza Island, off the South West coast of Greece. The deployment site provides excellent environmental characteristics. The deployed NESTOR module is constructed as a hexagonal star like latticed titanium star with 12 Optical Modules and an one-meter diameter titanium sphere which houses the electronics. Power and data were transferred through a 30km electro-optical cable to the shore laboratory. In this report we describe briefly the detector and the detector electronics and discuss the first physics data acquired and give the zenith angular distribution of the reconstructed muons.

  4. Diffractive X-Ray Telescopes

    Science.gov (United States)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  5. Diffractive X-ray Telescopes

    CERN Document Server

    Skinner, Gerald K

    2010-01-01

    Diffractive X-ray telescopes using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution several orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted space- time in the immediate vicinity of the super-massive black holes in the center of active galaxies What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  6. IR spectrometer project for the BTA telescope

    Science.gov (United States)

    Afanasiev, V. L.; Emelianov, E. V.; Murzin, V. A.; Vdovin, V. F.

    2013-07-01

    We introduce a project of new cooled infrared spectrometer-photometer for 6-m telescope BTA (Special Astrophysical Observatory of Russian Science Academy). The device would extend the wavelength range accessible for observations on the 6-m BTA telescope toward near infrared (0.8-2.5 um).

  7. A Mechanical Analogue of the Refracting Telescope

    Science.gov (United States)

    Vannoni, Maurizio; Molesini, Giuseppe; Sordini, Andrea; Straulino, Samuele

    2011-01-01

    The recent celebration of the discoveries made by Galileo four centuries ago has attracted new attention to the refracting telescope and to its use as an instrument for the observation of the night sky. This has offered the opportunity for addressing in the classroom the basic principles explaining the operation of the telescope. When doing so, a…

  8. Solar Magnetometry with the dutch open telescope

    NARCIS (Netherlands)

    Rutten, R.J.; Hammerschlag, R.H.; Sütterlin, P.; Bettonvil, F.C.M.; Zalm, E.B.J. van der

    2001-01-01

    The Dutch Open Telescope (DOT) has become op- erational at the Roque de los Muchachos Observa- tory on La Palma. The rst image sequences taken with this innovative telescope demonstrate its capa- bility for tomographic high-resolution imaging of the magnetic topology of the solar atmosphere up to th

  9. ANTARES : The first undersea neutrino telescope

    NARCIS (Netherlands)

    Ageron, M.; Aguilar, J. A.; Al Samarai, I.; Albert, A.; Ameli, F.; Andre, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Arnaud, K.; Aslanides, E.; Jesus, A. C. Assis; Astraatmadja, T.; Aubert, J. -J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Becherini, Y.; Beltramelli, J.; Bersani, A.; Bertin, V.; Beurthey, S.; Biagi, S.; Bigongiari, C.; Billault, M.; Blaes, R.; Bogazzi, C.; de Botton, N.; Bou-Cabo, M.; Boudahef, B.; Bouwhuis, M. C.; Brown, A. M.; Brunner, J.; Busto, J.; Caillat, L.; Calzas, A.; Camarena, F.; Capone, A.; Caponetto, L.; Carloganu, C.; Carminati, G.; Carmona, E.; Carr, J.; Carton, P. H.; Cassano, B.; Castorina, E.; Cecchini, S.; Ceres, A.; Chaleil, Th; Charvis, Ph; Chauchot, P.; Chiarusi, T.; Circella, M.; Compere, C.; Coniglione, R.; Coppolani, X.; Cosquer, A.; Costantini, H.; Cottini, N.; Coyle, P.; Cuneo, S.; Curtil, C.; D'Amato, C.; Damy, G.; van Dantzig, R.; De Bonis, G.; Decock, G.; Decowski, M. P.; Dekeyser, I.; Delagnes, E.; Desages-Ardellier, F.; Deschamps, A.; Destelle, J. -J.; Di Maria, F.; Dinkespiler, B.; Distefano, C.; Dominique, J. -L.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drogou, J. -F.; Drouhin, D.; Druillole, F.; Durand, D.; Durand, R.; Eberl, T.; Emanuele, U.; Engelen, J. J.; Ernenwein, J. -P.; Escoffier, S.; Falchini, E.; Favard, S.; Fehr, F.; Feinstein, F.; Ferri, M.; Ferry, S.; Fiorello, C.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J. -L.; Galata, S.; Galeotti, S.; Gay, P.; Gensolen, F.; Giacomelli, G.; Gojak, C.; Gomez-Gonzalez, J. P.; Goret, Ph.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Hartmann, B.; Heijboer, A. J.; Heine, E.; Hello, Y.; Henry, S.; Hernandez-Rey, J. J.; Herold, B.; Hoessl, J.; Hogenbirk, J.; Hsu, C. C.; Hubbard, J. R.; Jaquet, M.; Jaspers, M.; de Jong, M.; Jourde, D.; Kadler, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Karg, T.; Karkar, S.; Karolak, M.; Katz, U.; Keller, P.; Kestener, P.; Kok, E.; Kok, H.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Kruijer, A.; Kuch, S.; Kulikovskiy, V.; Lachartre, D.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lahonde-Hamdoun, C.; Lamare, P.; Lambard, G.; Languillat, J-C; Larosa, G.; Lavalle, J.; Le Guen, Y.; Le Provost, H.; LeVanSuu, A.; Lefevre, D.; Legou, T.; Lelaizant, G.; Leveque, C.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Lyashuk, V.; Magnier, P.; Mangano, S.; Marcel, A.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Masullo, R.; Mazeas, F.; Mazure, A.; Meli, A.; Melissas, M.; Migneco, E.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Neff, M.; Niess, V.; Nooren, G. J. L.; Oberski, J. E. J.; Olivetto, C.; Palanque-Delabrouille, N.; Patioselitis, D.; Papaleo, R.; Pavalas, G. E.; Payet, K.; Payre, P.; Peek, H.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Picq, C.; Piret, Y.; Poinsignon, J.; Popa, V.; Pradier, T.; Presani, E.; Prono, G.; Racca, C.; Raia, G.; van Randwijk, J.; Real, D.; Reed, C.; Rethore, F.; Rewiersma, P.; Riccobene, G.; Richardt, C.; Richter, R.; Ricol, J. S.; Rigaud, V.; Roca, V.; Roensch, K.; Rolin, J. -F.; Rostovtsev, A.; Rottura, A.; Roux, J.; Rujoiu, M.; Ruppi, M.; Russo, G. V.; Salesa, F.; Salomon, K.; Sapienza, P.; Schmitt, F.; Schoeck, F.; Schuller, J. -P.; Schuessler, F.; Sciliberto, D.; Shanidze, R.; Shirokov, E.; Simeone, F.; Sottoriva, A.; Spies, A.; Spona, T.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th; Streeb, K.; Sulak, L.; Taiuti, M.; Tamburini, C.; Tao, C.; Tasca, L.; Terreni, G.; Tezier, D.; Toscano, S.; Urbano, F.; Valdy, P.; Vallage, B.; Van Elewyck, V.; Vannoni, G.; Vecchi, M.; Venekamp, G.; Verlaat, B.; Vernin, P.; Virique, E.; de Vries, G.; Wijnker, G.; Wobbe, G.; de Wolf, E.; Yakovenko, Y.; Yepes, H.; Zaborov, D.; Zaccone, H.; Zornoza, J. D.; Zuniga, J.; van Wijk, R.

    2011-01-01

    The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design

  10. Lijiang 2.4m Optical Telescope

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The 2.4m optical telescope of Yunnan Observatory was installed at Lijiang Observatory in the northwest of the Yunnan Province in 2007, which became operational since May 2008. At present, it is the largest general-use optical telescope in East Asia.

  11. Hard x-ray telescope mission

    DEFF Research Database (Denmark)

    Gorenstein, P.; Worrall, D.; Joensen, K.D.

    1996-01-01

    The Hard X-Ray Telescope was selected for study as a possible new intermediate size mission for the early 21st century. Its principal attributes are: (1) multiwavelength observing with a system of focussing telescopes that collectively observe from the UV to over 1 MeV, (2) much higher sensitivity...

  12. IR Spectrometer Project for the BTA Telescope

    OpenAIRE

    Afanasiev, V. L.; Emelianov, E. V.; Murzin, V. A.; Vdovin, V. F.

    2013-01-01

    We introduce a project of new cooled infrared spectrometer-photometer for 6-m telescope BTA (Special Astrophysical Observatory of Russian Science Academy). The device would extend the wavelength range accessible for observations on the 6-m BTA telescope toward near infrared (0.8-2.5 um).

  13. Southern Fireworks above ESO Telescopes

    Science.gov (United States)

    1999-05-01

    New Insights from Observations of Mysterious Gamma-Ray Burst International teams of astronomers are now busy working on new and exciting data obtained during the last week with telescopes at the European Southern Observatory (ESO). Their object of study is the remnant of a mysterious cosmic explosion far out in space, first detected as a gigantic outburst of gamma rays on May 10. Gamma-Ray Bursters (GRBs) are brief flashes of very energetic radiation - they represent by far the most powerful type of explosion known in the Universe and their afterglow in optical light can be 10 million times brighter than the brightest supernovae [1]. The May 10 event ranks among the brightest one hundred of the over 2500 GRB's detected in the last decade. The new observations include detailed images and spectra from the VLT 8.2-m ANTU (UT1) telescope at Paranal, obtained at short notice during a special Target of Opportunity programme. This happened just over one month after that powerful telescope entered into regular service and demonstrates its great potential for exciting science. In particular, in an observational first, the VLT measured linear polarization of the light from the optical counterpart, indicating for the first time that synchrotron radiation is involved . It also determined a staggering distance of more than 7,000 million light-years to this GRB . The astronomers are optimistic that the extensive observations will help them to better understand the true nature of such a dramatic event and thus to bring them nearer to the solution of one of the greatest riddles of modern astrophysics. A prime example of international collaboration The present story is about important new results at the front-line of current research. At the same time, it is also a fine illustration of a successful collaboration among several international teams of astronomers and the very effective way modern science functions. It began on May 10, at 08:49 hrs Universal Time (UT), when the Burst

  14. LUNASKA simultaneous neutrino searches with multiple telescopes

    CERN Document Server

    Bray, J D; James, C W; Roberts, P; Brown, A; Phillips, C J; Protheroe, R J; Reynolds, J E; McFadden, R A; Aartsen, M

    2011-01-01

    The most sensitive method for detecting neutrinos at the very highest energies is the lunar Cherenkov technique, which employs the Moon as a target volume, using conventional radio telescopes to monitor it for nanosecond-scale pulses of Cherenkov radiation from particle cascades in its regolith. Multiple-antenna radio telescopes are difficult to effectively combine into a single detector for this purpose, while single antennas are more susceptible to false events from radio interference, which must be reliably excluded for a credible detection to be made. We describe our progress in excluding such interference in our observations with the single-antenna Parkes radio telescope, and our most recent experiment (taking place the week before the ICRC) using it in conjunction with the Australia Telescope Compact Array, exploiting the advantages of both types of telescope.

  15. Calibration of the Cherenkov Telescope Array

    CERN Document Server

    Gaug, Markus; Berge, David; Reyes, Raquel de los; Doro, Michele; Foerster, Andreas; Maccarone, Maria Concetta; Parsons, Dan; van Eldik, Christopher

    2015-01-01

    The construction of the Cherenkov Telescope Array is expected to start soon. We will present the baseline methods and their extensions currently foreseen to calibrate the observatory. These are bound to achieve the strong requirements on allowed systematic uncertainties for the reconstructed gamma-ray energy and flux scales, as well as on the pointing resolution, and on the overall duty cycle of the observatory. Onsite calibration activities are designed to include a robust and efficient calibration of the telescope cameras, and various methods and instruments to achieve calibration of the overall optical throughput of each telescope, leading to both inter-telescope calibration and an absolute calibration of the entire observatory. One important aspect of the onsite calibration is a correct understanding of the atmosphere above the telescopes, which constitutes the calorimeter of this detection technique. It is planned to be constantly monitored with state-of-the-art instruments to obtain a full molecular and...

  16. A telescope with augmented reality functions

    Science.gov (United States)

    Hou, Qichao; Cheng, Dewen; Wang, Qiwei; Wang, Yongtian

    2016-10-01

    This study introduces a telescope with virtual reality (VR) and augmented reality (AR) functions. In this telescope, information on the micro-display screen is integrated to the reticule of telescope through a beam splitter and is then received by the observer. The design and analysis of telescope optical system with AR and VR ability is accomplished and the opto-mechanical structure is designed. Finally, a proof-of-concept prototype is fabricated and demonstrated. The telescope has an exit pupil diameter of 6 mm at an eye relief of 19 mm, 6° field of view, 5 to 8 times visual magnification , and a 30° field of view of the virtual image.

  17. Optical design of a rotating eyepiece telescope

    Science.gov (United States)

    Siddique, M.; Nasim, F.; Khan, A. N.; Gul, A.

    2016-08-01

    Flexible eyepiece telescope has been designed and verified. The rotating eyepiece of telescope will facilitate viewing of objects in a remote or out of sight target. Eyepiece arm of telescope can be rotated upto 360o keeping objective and reticule unchanged and ensuring zero deviation in reticule inclination. Main application of this scope is off axis viewing of objects. Image inversion has been carried out by using pair of mirrors and length of telescope is controlled by using relay lenses. The optical design, simulation and image analysis has been carried out by using ZEMAX®. Magnification of telescope is between 10∼⃒12 times with FOV of 60. Experiment has been carried out using uncoated Edmund Optics and optical tool box of Micro Series Kit, NEWPORT.

  18. Performance of the SST-1M telescope for the Cherenkov Telescope Array observatory

    CERN Document Server

    Moderski, R; Błocki, J.; Bogacz, L.; Bulik, T.; Cadoux, F.; Christov, A.; Chruślińska, M.; Curyło, M.; della Volpe, D.; Dyrda, M.; Favre, Y.; Frankowski, A.; Grudnik, Ł.; Grudzińska, M.; Heller, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandat, D.; Marszałek, A.; Michałowski, J.; Montaruli, T.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Pech, M.; Porcelli, A.; Prandini, E.; Pueschel, E.; Rajda, P.; Rameez, M.; Rozwadowski, P.; Schioppa, E. jr; Schovanek, P.; Seweryn, K.; Skowron, K.; Sliusar, V.; Sowiński, M.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Toscano, S.; Pujadas, I. Troyano; Walter, R.; Wiȩcek, M.; Zagdański, A.; Ziȩtara, K.; Żychowski, P.

    2015-01-01

    The single mirror small-size telescope (SST-1M) is one of the telescope projects being proposed for the Cherenkov Telescope Array observatory by a sub-consortium of Polish and Swiss institutions. The SST-1M prototype structure is currently being constructed at the Institute of Nuclear Physics in Cracow, Poland, while the camera will be assembled at the University of Geneva, Switzerland. This prototype enables measurements of parameters having a decisive influence on the telescope performance. We present results of numerical simulations of the SST-1M performance based on such measurements. The telescope effective area, the expected trigger rates and the optical point spread function are calculated.

  19. Design of the STAR-X Telescope

    Science.gov (United States)

    Saha, Timo T.; Zhang, William W.; McClelland, Ryan S.

    2017-01-01

    Top-level science goals of the Survey and Time-domain Astrophysical Research eXplorer (STAR-X) include: investigations of most violent explosions in the universe, study of growth of black holes across cosmic time and mass scale, and measure how structure formation heats majority of baryons in the universe. To meet these goals, the field-of-view of the telescope should be about 1 square-degree, the angular resolution should be 5 arc-seconds or below across large part of the field-of-view. The on-axis effective area at 1 KeV should be about 2,000 sq cm. Payload cost and launch considerations limit the outer diameter, focal length, and mass to 1.3 meters, 5 meters, and 250 kilograms, respectively. Telescope design is based on a segmented meta-shell approach we have developed at Goddard Space Flight Center for the STAR-X telescope. The telescope shells are divided into 30-degree segments. Individual telescopes and meta-shells are nested inside each other to meet the effective area requirements in 0.5 - 6.0 KeV range. We consider Wolter-Schwarzschild, and Modified-Wolter-Schwarzschild telescope designs as basic building blocks of the nested STAR-X telescope. These designs offer an excellent resolution over a large field of views. Nested telescopes are vulnerable to stray light problems. We have designed a multi-component baffle system to eliminate direct and single-reflection light paths inside the telescopes. Large number of internal and external baffle vane structures are required to prevent stray rays from reaching the focal plane. We have developed a simple ray-trace based tool to determine the dimensions and locations of the baffles. In this paper, we present the results of our trade studies, baffle design studies, and optical performance analyses of the STAR-X telescope.

  20. Beyond the Hubble Space Telescope: Early Development of the Next Generation Space Telescope

    Science.gov (United States)

    Smith, Robert W.; Patrick McCray, W.

    In this paper we investigate the early history of what was at first called the Next Generation Space Telescope, later to be renamed the James Webb Space Telescope. We argue that the initial ideas for such a Next Generation Space Telescope were developed in the context of the planning for a successor to the Hubble Space Telescope. Much the most important group of astronomers and engineers examining such a successor was based at the Space Telescope Science Institute in Baltimore. By the late 1980s, they had fashioned concepts for a successor that would work in optical, ultraviolet and infrared wavelengths, concepts that would later be regarded as politically unrealistic given the costs associated with them. We also explore how the fortunes of the planned Next Generation Space Telescope were intimately linked to that of its "parent," the Hubble Space Telescope.

  1. Monte Carlo Studies of medium-size telescope designs for the Cherenkov Telescope Array

    CERN Document Server

    Wood, M; Dumm, J; Funk, S

    2015-01-01

    We present studies for optimizing the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Results focus on mid-sized telescopes (MSTs) for CTA, detecting very high energy gamma rays in the energy range from a few hundred GeV to a few tens of TeV. We describe a novel, flexible detector Monte Carlo package, FAST (FAst Simulation for imaging air cherenkov Telescopes), that we use to simulate different array and telescope designs. The simulation is somewhat simplified to allow for efficient exploration over a large telescope design parameter space. We investigate a wide range of telescope performance parameters including optical resolution, camera pixel size, and light collection area. In order to ensure a comparison of the arrays at their maximum sensitivity, we analyze the simulations with the most sensitive techniques used in the field, such as maximum likelihood template reconstruction and boosted decision trees for background rejection. Choosing telescope design parameters repre...

  2. The Large Millimeter Telescope (LMT)

    Science.gov (United States)

    Young, J. S.; Carrasco, L.; Schloerb, F. P.

    2002-05-01

    The Large Millimeter Telescope (LMT) project is a collaboration between the University of Massachusetts (UMass) in the USA and the Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) in Mexico to build a 50m-diameter millimeter-wave antenna which will operate with good efficiency at wavelengths as short as 1 mm. The LMT is being built at an altitude of 4600 m atop Volcan Sierra Negra, an extinct volcanic peak in the state of Puebla, Mexico, approximately 100 km east of the city of Puebla. At 18 degrees 59' N latitude, the site offers an excellent view of the Galactic Center and good sky coverage of both hemispheres. Construction of the telescope is now well underway, and it is expected to be completed in late 2004. The LMT specifications call for an overall effective surface accuracy of 75 microns rms and a pointing accuracy of 1" rms. The strategy for meeting these performance goals supplements conventional antenna designs with various "active" systems to bring the final performance within the requirements. For surface accuracy, the LMT will rely on an open loop active surface which includes 180 moveable surface segments. For pointing accuracy, we will use traditional approaches supplemented by measurements to characterize the behavior of the structure, including inclinometers and temperature sensors which may be used with finite element models to determine structural deformations and predict pointing behavior. The initial complement of instruments will include a 32 element, heterodyne focal plane array at 3mm; a large format, focal plane bolometer array; a unique wide band receiver and spectrometer to determine the redshifts of primordial galaxies; and a 4 element receiver for the 1mm band. With its excellent sensitivity and angular resolution, the LMT will enable unique studies of the early universe and galaxy evolution, the interstellar medium and star formation in galaxies, and planetary science. In particular, with nearly 2000 m2 of collecting

  3. Spitzer Space Telescope proposal process

    Science.gov (United States)

    Laine, S.; Silbermann, N. A.; Rebull, L. M.; Storrie-Lombardi, L. J.

    2006-06-01

    This paper discusses the Spitzer Space Telescope General Observer proposal process. Proposals, consisting of the scientific justification, basic contact information for the observer, and observation requests, are submitted electronically using a client-server Java package called Spot. The Spitzer Science Center (SSC) uses a one-phase proposal submission process, meaning that fully-planned observations are submitted for most proposals at the time of submission, not months after acceptance. Ample documentation and tools are available to the observers on SSC web pages to support the preparation of proposals, including an email-based Helpdesk. Upon submission proposals are immediately ingested into a database which can be queried at the SSC for program information, statistics, etc. at any time. Large proposals are checked for technical feasibility and all proposals are checked against duplicates of already approved observations. Output from these tasks is made available to the Time Allocation Committee (TAC) members. At the review meeting, web-based software is used to record reviewer comments and keep track of the voted scores. After the meeting, another Java-based web tool, Griffin, is used to track the approved programs as they go through technical reviews, duplication checks and minor modifications before the observations are released for scheduling. In addition to detailing the proposal process, lessons learned from the first two General Observer proposal calls are discussed.

  4. Telescopes for the 1980s

    Science.gov (United States)

    Neugebauer, G.

    In the last decades, astronomy has been changed in a number of significant ways. The number of large optical telescopes with diameters on the order of or larger than 2.3 m has increased from 3 shortly after World War II to about 20 at the present time. Whereas prewar astronomy was largely devoted to the visual wavelengths (0.3-0.8 μm), astronomical observations currently span the range from γ ray wavelengths to the longest radio wavelengths. Most significantly, astronomy outside conventional optical astronomy has developed into sophisticated disciplines rather than experimental explorations. Many of the observational advances at the forefront of astronomy now come from other than visual observations. Along with these changes have come fundamental changes in visual astronomy itself. Observations with photographic plates are the exception rather than the rule at most large observatories. Instead, electronic cameras are in common use. A second change, especially in the United States, is that the funding has gone from largely private funding (e.g., the Carnegie Institution of Washington) to funding with the government providing a main share of the support. Indeed, the government has provided the total funding for those disciplines, like X ray astronomy, which use space-borne platforms. These changes have also affected the character of doing astronomy, and astronomers have become much more politically active on the national science scene.

  5. Proposed National Large Solar Telescope

    Indian Academy of Sciences (India)

    Jagdev Singh

    2008-03-01

    Sun’s atmosphere is an ideal place to study and test many magnetohydrodynamic (MHD) processes controlling turbulent plasma. We wish to resolve some of the finest solar features (which remain unresolved presently) and study their dynamics. Indian Institute of Astrophysics has proposed to design, fabricate and install a 2-meter class solar telescope at a suitable site in India to resolve features on the Sun of the size of about 0.1 arcsec. The focal plane instruments will include a high resolution polarimeteric package to measure polarization with an accuracy of 0.01 per cent; a high spectral resolution spectrograph to obtain spectra in 5 widely separated absorption lines simultaneously and high spatial resolution narrow band imagers in various lines. The Himalayan region appears to be a good choice keeping in view the prevailing dry and clear weather conditions. We have started detailed analysis of the weather conditions in the area and at some other locations in India. The site characterization will be done using the Sun-photometer, S-DIMM and SHABAR techniques to determine the seeing conditions.

  6. The James Webb Space Telescope

    CERN Document Server

    Gardner, J P; Clampin, M; Doyon, R; Greenhouse, M A; Hammel, H B; Hutchings, J B; Jakobsen, P; Lilly, S J; Long, K S; Lunine, J I; McCaughrean, M J; Mountain, M; Nella, J; Rieke, G H; Rieke, M J; Rix, H W; Smith, E P; Sonneborn, G; Stiavelli, M; Stockman, H S; Windhorst, R A; Wright, G S; Gardner, Jonathan P.; Mather, John C.; Clampin, Mark; Doyon, Rene; Greenhouse, Matthew A.; Hammel, Heidi B.; Hutchings, John B.; Jakobsen, Peter; Lilly, Simon J.; Long, Knox S.; Lunine, Jonathan I.; Caughrean, Mark J. Mc; Mountain, Matt; Nella, John; Rieke, George H.; Rieke, Marcia J.; Rix, Hans-Walter; Smith, Eric P.; Sonneborn, George; Stiavelli, Massimo; Windhorst, Rogier A.; Wright, Gillian S.

    2006-01-01

    The James Webb Space Telescope (JWST) is a large (6.6m), cold (50K), infrared-optimized space observatory that will be launched early in the next decade. The observatory will have four instruments: a near-infrared camera, a near-infrared multi-object spectrograph, and a tunable filter imager will cover the wavelength range, 0.6 to 5.0 microns, while the mid-infrared instrument will do both imaging and spectroscopy from 5.0 to 29 microns. The JWST science goals are divided into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the early universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present day. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall on to dust-e...

  7. Very large Arecibo-type telescopes

    Science.gov (United States)

    Drake, Frank D.

    1988-03-01

    The Arecibo-type radio telescope, based on a fixed spherical reflector, is a very effective design for a large radio telescope on the Moon. In such telescopes, major structural members are provided by the ground on which they are built, and thus are provided at no cost in materials or transportation. The strong compression members, the tall towers which support the suspended platform, are an expensive part of the Arecibo telescope. The need for such towers can be eliminated if a suitable valley or crater can be found wherein the rim of the depression can be used as the support point for the cables which support the suspended platform. With an Arecibo-type radio telescope on the Moon, there are no changing gravity loads because of the design and no changing wind loads because of the location; therefore, the only source of time variation in the telescope geometry is thermal changes. Calculations show that with conventional materials, such as steel, it should be possible to construct an Arecibo-type telescope with a reflector diameter of some 30 km on the Moon, and with a reflector diameter of some 60 to 90 km if materials of high specific strength are used.

  8. Calvin-Rehoboth Robotic Twin Telescopes

    Science.gov (United States)

    Haarsma, D. B.; Molnar, L. A.; VanBaak, D. A.

    2004-12-01

    The astronomy program at Calvin College, like many small colleges, is limited by poor weather and light pollution at its midwestern campus and by limited free time on the part of its astronomy faculty. Nonetheless we believe direct access to the physical universe is key to the science education both of science majors and nonmajors. Recent advances in hardware and software for modest robotic telescopes have made it possible for colleges like ours to incorporate the use of a remote bservatory into our curriculum within typical financial and time constraints. In this poster we make our first report on the installation of two robotic telescopes (one on campus and one at a remote site in New Mexico) using largely off-the-shelf components. Students learn first with the local telescope in order to understand the equipment and procedures, but obtain the majority of their data with the remote telescope. Equipment development is done first with the local telescope, and then implemented on the remote telescope (where time spent in development is difficult). We received an NSF CCLI grant and matching college funds in the summer of 2002. The local telescope was installed in the spring of 2003, and the New Mexico telescope was ready for remote operation in January 2004. Our poster will describe our equipment choices, including a few components (such as an equipment rack for the back end of the telescope) which we designed ourselves. It will also detail classroom use of the equipment in its first two semesters by students at a range of levels. A copy of the poster and many additional details of the project are available on the Calvin observatory website, http://www.calvin.edu/observatory/.

  9. Telescoping cylindrical piezoelectric fiber composite actuator assemblies

    Science.gov (United States)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

    2010-01-01

    A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

  10. The Thirty Meter Telescope (TMT) Project

    Science.gov (United States)

    Sanders, G.; TMT Project

    2004-12-01

    The Thirty Meter Telescope (TMT) Project is engaged in a design and development phase. TMT is proposed as a private-public partnership of the California Institute of Technology and the University of California (partners in the earlier CELT design study), AURA (designers of the earlier GSMT concept), and the Canadian ACURA consortium (designers of the VLOT concept). The partners are developing a 30 meter diameter, finely segmented filled aperture telescope with seeing-limited and diffraction-limited capabilities to address the broad range of GSMT science goals. The paper will present the status of the project development and telescope and instrument design.

  11. The GREGOR solar telescope on Tenerife

    CERN Document Server

    Schmidt, Wolfgang; Volkmer, Reiner; Denker, Carsten; Solanki, Sami; Balthasar, Horst; Gonzalez, Nazaret Bello; Berkefeld, Thomas; Collados, Manuel; Hofmann, Axel; Kneer, Franz; Lagg, Andreas; Puschmann, Klaus; Schmidt, Dirk; Sobotka, Michal; Soltau, Dirk; Strassmeier, Klaus

    2012-01-01

    2011 was a successful year for the GREGOR project. The telescope was finally completed in May with the installation of the 1.5-meter primary mirror. The installation of the first-light focal plane instruments was completed by the end of the year. At the same time, the preparations for the installation of the high-order adaptive optics were finished, its integration to the telescope is scheduled for early 2012. This paper describes the telescope and its instrumentation in their present first light configuration, and provides a brief overview of the science goals of GREGOR.

  12. California Extremely Large Telescope : conceptual design for a thirty-meter telescope

    Science.gov (United States)

    Following great success in the creation of the Keck Observatory, scientists at the California Institute of Technology and the University of California have begun to explore the scientific and technical prospects for a much larger telescope. The Keck telescopes will remain the largest telescopes in the world for a number of years, with many decades of forefront research ahead after that. Though these telescopes have produced dramatic discoveries, it is already clear that even larger telescopes must be built if we are to address some of the most profound questions about our universe. The time required to build a larger telescope is approximately ten years, and the California community is presently well-positioned to begin its design and construction. The same scientists who conceived, led the design, and guided the construction of the Keck Observatory have been intensely engaged in a study of the prospects for an extremely large telescope. Building on our experience with the Keck Observatory, we have concluded that the large telescope is feasible and is within the bounds set by present-day technology. Our reference telescope has a diameter of 30 meters, the largest size we believe can be built with acceptable risk. The project is currently designated the California Extremely Large Telescope (CELT).

  13. Using Small Telescopes, Citizen Science, and Network Surveys to find Exoplanets - An Overview of the Kelt team and the Exoplanets Found to Date

    Science.gov (United States)

    Stephens, Denise C.; Kelt North Survey Team, Kelt South Survey Team

    2016-10-01

    The Kelt-North and Kelt-South transit survey is a wide angle search for hot Jupiters around some of the brightest stars in the night sky. Survey operations are based out of the Ohio State and Vanderbilt Universities, with observing facilities at Winer Observatory in Arizona and in Sutherland, South Africa. KELT stands for Kilodegree Extremely Little Telescope, where "Kilodegree" refers to the large area on the sky that the telescope can observe in a single shot. These "Little Telescopes" monitor the brightness of hundreds of thousands of stars night after night, month after month, for many years. Stars that show apparent changes in brightness are put through a careful vetting process and the best transiting planet candidates are sent on for photometric follow-up by a ground based team made up of nearly 40 members in 10 countries across 4 continents. The KELT Follow-Up Network is the largest, most coordinated network of its kind, and their work has contributed to the discovery of multiple new planets: including Kelt-1b which is a 30 Jupiter-mass object at an orbital period of 1.2 days; Kelt-6b wich is a Hot Saturn on a 7.9 day orbital period; and Kelt-8b which is a highly inflated Hot Jupiter that required the development of new techniques to extract high-precision radial velocities. In this presentation I will highlight all of the Kelt Exoplanets discovered to date and how the Kelt team is using small telescopes, citizen science, and network surveys to make these discoveries possible.

  14. Frequency-modulated second elements of two-element alarm calls do not enhance discrimination of callers in three Eurasian ground squirrels

    Institute of Scientific and Technical Information of China (English)

    Irena SCHNEIDEROV(A)

    2012-01-01

    Alarm calls of the European Spermophilus citellus (EGS),Taurus S.taurensis (TGS) and Anatolian S.xanthoprymnus (AGS) ground squirrels share the same basic structure.They are tonal sounds consisting primarily of two different elements.The first element,often produced without the second element,has limited frequency modulation,while the second element is more frequency modulated.The present study examined whether this frequency-modulated element enhances the individual distinctiveness of calls,allowing calls to be ascribed with greater confidence to individual callers of the three species.Cross-validated discriminant function analysis (DFA) based on five acoustic parameters of the first element successfully classified calls to correct individuals (EGS:90%,TGS:98%,AGS:96%).Cross-validated DFA based on five acoustic parameters of the second element was also successful in classifications (EGS:88%,TGS:86%,AGS:96%),though discrimination of callers based on parameters of the second versus first element was the same for the AGS,lower for the EGS and significantly lower for the TGS.Cross-validated DFA based on five acoustic parameters of two-element calls also successfully classified calls to correct individuals (EGS:93%,TGS:98%,AGS:97%),though did not improve the extent to which calls could be classified to individuals beyond that based on the first element alone.Thus,the second element does not enhance the individual distinctiveness of calls,but may convey other information such as the location of the caller.

  15. The ALMA Telescope Control System

    Science.gov (United States)

    Farris, A.; Marson, Ralph; Kern, Jeff

    2005-10-01

    The Atacama Large Millimeter Array (ALMA) is a joint project between North America, Europe and Japan. ALMA is an aperture synthesis radio telescope consisting of 50 12-meter antennas located at an elevation of 5,000 meters in Llano de Chajnantor, Chile. These antennas will operate at frequencies ranging from 31.3 GHz to 950 GHz. The antennas can be moved and placed in different configurations, with baselines between the antennas varying from 150 meters to 20 km. The 50 antennas are supplemented by sixteen additional ones, known as the ALMA Compact Array (ACA): 12 7-meter antennas and 4 12-meter antennas. The ALMA control system will consist of over 70 computers separated by distances of over 20 km. Two aspects of the system are apparent: its distributed nature and its need to accurately synchronize events across many computers separated by large distances. In this paper we describe key features of the architecture of the ALMA Control System, focusing on its properties as a distributed system and on the mechanisms employed to achieve its time synchronization goals. This control system is a distributed system that uses the ALMA Common Software (ACS) as a middleware system layered on top of CORBA. The architecture of the control system extensively employs the component/container model in ACS. In addition, the use of CORBA allows us to employ Java in the higher levels of the control system, leaving C++ to the lower time-critical levels. Python as a scripting language is used by astronomers, to craft standard observing programs, and engineers, in a testing and debugging mode. Key to the concept of an aperture synthesis telescope is a special purpose hardware system known as a correlator, responsible for making various delay model corrections and correlating the signals from the antennas. There are two correlators in ALMA, one for the array of 50 antennas and one for the ACA. This entire system operates under a control system that must synchronize events across the

  16. Lightweight composite mirrors for telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lightweight, steady and stiff mirrors are necessary to decrease cost of telescopes such as IXO and GenX used in special NASA missions. Low-density materials are...

  17. Introduction to the Solar Space Telescope

    Indian Academy of Sciences (India)

    G. Ai; S. Jin; S. Wang; B. Ye; S. Yang

    2000-09-01

    The design of the space solar telescope (SST) (phase B) has been completed. The manufacturing is under development. At the end of 2000, it will be assembled. The basic aspect will be introduced in this paper.

  18. Beam Combination for Sparse Aperture Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Stellar Imager, an ultraviolet, sparse-aperture telescope, was one of the fifteen Vision Missions chosen for a study completed last year. Stellar Imager will...

  19. Goldstone Apple Valley Radio Telescope Project.

    Science.gov (United States)

    Ibe, Mary; MacLaren, Dave

    2003-01-01

    Describes the Goldstone Apple Valley Radio Telescope (GAVRT) project as a way of teaching astronomy concepts to middle school students. The project provides students opportunities to work with professional scientists. (SOE)

  20. EDUCATIONAL ASTRONOMICAL OBSERVATIONS ON REMOTE ACCESS TELESCOPES

    Directory of Open Access Journals (Sweden)

    Ivan P. Kriachko

    2016-01-01

    Full Text Available The purpose of this article is to show the way of overcoming one of the major problems of astronomy teaching methods in upper secondary school – organization of educational astronomical observations. Nowadays it became possible to perform such observations on remote access telescopes. By using up-to-date informational and communicational technologies, having an opportunity to work with robotic telescopes allows us to organize a unique cognitive and research oriented activities for students while conducting their specialized astronomical studies. Below here is given a brief description of the most significant robotic telescopes and the way of the usage of open remote access telescopic network which was created by professors and scientists of Harvard-Smithsonian Center for Astrophysics, USA.

  1. Atmospheric Monitoring for the MAGIC Telescopes

    CERN Document Server

    Gaug, M; Dorner, D; Doro, M; Font, Ll; Fruck, C; Garczarczyk, M; Garrido, D; Hrupec, D; Hose, J; López-Oramas, A; Maneva, G; Martinez, M; Mirzoyan, R; Temnikov, P; Zanin, R

    2014-01-01

    The monitoring of the atmosphere is very relevant for Imaging Atmospheric Cherenkov Telescopes. Adverse weather conditions (strong wind, high humidity, etc.) may damage the telescopes and must therefore be monitored continuously to guarantee a safe operation, and the presence of clouds and aerosols affects the transmission of the Cherenkov light and consequently the performance of the telescopes. The ATmospheric CAlibration (ATCA) technical working group of the MAGIC collaboration aims to cover all aspects related to atmosphere monitoring and calibration. In this paper we give an overview of the ATCA goals and activities, which include the set-up and maintenance of appropriate instrumentation, proper analysis of its data, the realization of MC studies, and the correction of real data taken under non-optimal atmospheric conditions. The final goal is to reduce the systematic uncertainties in the determination of the $\\gamma$-ray flux and energy, and to increase the duty cycle of the telescopes by establishing o...

  2. a New Concept of Agile Telescope

    Directory of Open Access Journals (Sweden)

    Michael Valasek

    2010-01-01

    Full Text Available The paper deals with the description of a new concept for a spherical mechanism for agile telescopes. It is based on redundantly actuated parallel kinematical structure. Due to the three times overactuated structure and application of several further innovative concepts, the Hexasphere achieves the movability of ±100 degrees. This enables the use of a Hexasphere as the basis for mounts of telescopes. Such telescopes can be optimized for minimum weight or for maximum dynamics. The proposed mechanism is expected to play a role in novel robotic telescopes nowadays used in many fields of astronomy and astrophysics, with emphasis on automated systems for alert observations of celestial gamma-ray bursts.

  3. The misalignment induced aberrations of TMA telescopes.

    Science.gov (United States)

    Thompson, Kevin P; Schmid, Tobias; Rolland, Jannick P

    2008-12-08

    The next major space-borne observatory, the James Webb Space Telescope, will be a 6.6M field-biased, obscured, three-mirror anastigmat (TMA). Over the used field of view, the performance of TMA telescopes is dominated by 3(rd) order misalignment aberrations. Here it is shown that two dominant 3(rd) order misalignment aberrations arise for any TMA telescope. One aberration, field constant 3(rd) order coma is a well known misalignment aberration commonly seen in two-mirror Ritchey Chretien telescopes. The second aberration, field-asymmetric, field-linear, 3(rd) order astigmatism is a new and unique image orientation dependence with field derived here for the first time using nodal aberration theory.

  4. Beam Combination for Sparse Aperture Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for funding to continue development of an alternative beam combiner for Stellar Imager (SI), a 30-aperture, interferometric telescope chosen as one...

  5. Mirror-concentrator for space telescope with wide field of view and "high" angular resolution for observation of ultrahigh energy cosmic rays and other atmospheric flashes

    Science.gov (United States)

    Sharakin, Sergey A.; Khrenov, Boris A.; Klimov, Pavel A.; Panasyuk, Mikhail I.; Potanin, Sergey A.; Yashin, Ivan V.

    2012-09-01

    Idea of ultrahigh cosmic rays (UHECR) measurement from satellites was suggested by Linsley in 1981 and since has being developed into projects of cosmic rays telescopes for International Space Station (ISS): JEM-EUSO - to be installed on the Japanese experimental module and KLYPVE - on the Russian ISS segment. A series of space-based detectors for measurements of background phenomena in those telescopes were developed in Russia (Universitetsky-Tatiana, Universitetsky-Tatiana-2 , Chibis satellites). The satellite Lomonosov with UHECR detector TUS on its board will be launched in 2013. TUS contains multi-channel photo receiver and Fresnel-type mirror manufactured with use of special multi-layer carbon plastic technology in RSC “Energia". In this paper one and two component optical systems with 360 cm entrance diameter and 400 cm focal distance for wide angle detector KLYPVE are studied. In one component case using generalized Davies-Cotton systems (Fresnel-type mirror with ellipsoidal gross surface) it is possible to obtain 8-10° field of view (FoV) with focal spot size less than pixel size equal to 15 x 15 mm. In two component system (parabolic mirror and a Fresnel lens, mounted close to photo receiver) it is possible to increase FoV up to 10-12° and significantly simplify the primary mirror construction.

  6. The MuPix Telescope: A Thin, high Rate Tracking Telescope

    CERN Document Server

    Augustin, H; Dittmeier, S; Grzesik, C; Hammerich, J; Huang, Q; Huth, L; Kiehn, M; Kozlinskiy, A; Meier, F; Perić, I; Perrevoort, A -K; Schöning, A; Bruch, D vom; Wauters, F; Wiedner, D

    2016-01-01

    The MuPix Telescope is a particle tracking telescope, optimized for tracking low momentum particles and high rates. It is based on the novel High-Voltage Monolithic Active Pixel Sensors (HV-MAPS), designed for the Mu3e tracking detector. The telescope represents a first application of the HV-MAPS technology and also serves as test bed of the Mu3e readout chain. The telescope consists of up to eight layers of the newest prototypes, the MuPix7 sensors, which send data self-triggered via fast serial links to FPGAs, where the data is time-ordered and sent to the PC. A particle hit rate of 1 MHz per layer could be processed. Online tracking is performed with a subset of the incoming data. The general concept of the telescope, chip architecture, readout concept and online reconstruction are described. The performance of the sensor and of the telescope during test beam measurements are presented.

  7. A 16-m Telescope for the Advanced Technology Large Aperture Telescope (ATLAST) Mission

    Science.gov (United States)

    Lillie, Charles F.; Dailey, D. R.; Polidan, R. S.

    2010-01-01

    Future space observatories will require increasingly large telescopes to study the earliest stars and galaxies, as well as faint nearby objects. Technologies now under development will enable telescopes much larger than the 6.5-meter diameter James Webb Space Telescope (JWST) to be developed at comparable costs. Current segmented mirror and deployable optics technology enables the 6.5 meter JWST telescope to be folded for launch in the 5-meter diameter Ariane 5 payload fairing, and deployed autonomously after reaching orbit. Late in the next decade, when the Ares V Cargo Launch Vehicle payload fairing becomes operational, even larger telescope can be placed in orbit. In this paper we present our concept for a 16-meter JWST derivative, chord-fold telescope which could be stowed in the 10-m diameter Ares V fairing, plus a description of the new technologies that enable ATLAST to be developed at an affordable price.

  8. TALON - The Telescope Alert Operation Network System: Intelligent Linking of Distributed Autonomous Robotic Telescopes

    CERN Document Server

    White, R R; Davis, H; Galassi, M; Starr, D; Vestrand, W T; Wozniak, P

    2004-01-01

    The internet has brought about great change in the astronomical community, but this interconnectivity is just starting to be exploited for use in instrumentation. Utilizing the internet for communicating between distributed astronomical systems is still in its infancy, but it already shows great potential. Here we present an example of a distributed network of telescopes that performs more efficiently in synchronous operation than as individual instruments. RAPid Telescopes for Optical Response (RAPTOR) is a system of telescopes at LANL that has intelligent intercommunication, combined with wide-field optics, temporal monitoring software, and deep-field follow-up capability all working in closed-loop real-time operation. The Telescope ALert Operations Network (TALON) is a network server that allows intercommunication of alert triggers from external and internal resources and controls the distribution of these to each of the telescopes on the network. TALON is designed to grow, allowing any number of telescope...

  9. Solar Rejection Filter for Large Telescopes

    Science.gov (United States)

    Hemmati, Hamid; Lesh, James

    2009-01-01

    To reject solar radiation photons at the front aperture for large telescopes, a mosaic of large transmission mode filters is placed in front of the telescope or at the aperture of the dome. Filtering options for effective rejection of sunlight include a smaller filter down-path near the focus of the telescope, and a large-diameter filter located in the front of the main aperture. Two types of large filters are viable: reflectance mode and transmittance mode. In the case of reflectance mode, a dielectric coating on a suitable substrate (e.g. a low-thermal-expansion glass) is arranged to reflect only a single, narrow wavelength and to efficiently transmit all other wavelengths. These coatings are commonly referred to as notch filter. In this case, the large mirror located in front of the telescope aperture reflects the received (signal and background) light into the telescope. In the case of transmittance mode, a dielectric coating on a suitable substrate (glass, sapphire, clear plastic, membrane, and the like) is arranged to transmit only a single wavelength and to reject all other wavelengths (visible and near IR) of light. The substrate of the large filter will determine its mass. At first glance, a large optical filter with a diameter of up to 10 m, located in front of the main aperture, would require a significant thickness to avoid sagging. However, a segmented filter supported by a structurally rugged grid can support smaller filters. The obscuration introduced by the grid is minimal because the total area can be made insignificant. This configuration can be detrimental to a diffraction- limited telescope due to diffraction effects at the edges of each sub-panel. However, no discernable degradation would result for a 20 diffraction-limit telescope (a photon bucket). Even the small amount of sagging in each subpanel should have minimal effect in the performance of a non-diffraction limited telescope because the part has no appreciable optical power. If the

  10. The Automated Palomar 60 Inch Telescope

    Science.gov (United States)

    Cenko, S. Bradley; Fox, Derek B.; Moon, Dae-Sik; Harrison, Fiona A.; Kulkarni, S. R.; Henning, John R.; Guzman, C. Dani; Bonati, Marco; Smith, Roger M.; Thicksten, Robert P.; Doyle, Michael W.; Petrie, Hal L.; Gal-Yam, Avishay; Soderberg, Alicia M.; Anagnostou, Nathaniel L.; Laity, Anastasia C.

    2006-10-01

    We have converted the Palomar 60 inch (1.52 m) telescope from a classic night-assistant-operated telescope to a fully robotic facility. The automated system, which has been operational since 2004 September, is designed for moderately fast (tdesign requirements, hardware and software upgrades, and lessons learned from roboticization. We present an overview of the current system performance as well as plans for future upgrades.

  11. CLIC Telescope optimization with ALLPIX simulation

    CERN Document Server

    Qi, Wu

    2015-01-01

    A simulation study of CLIC-EUDET telescope resolution with MIMOSA 26 as reference sensors under DESY (5.6 GeV electron beam) and CERN-SPS (120-180 GeV pion^{-} beam) conditions. During the study, a virtual DUT sensor with cylindrical sensing area was defined and used with ALLPIX software. By changing the configuration of telescope, some results for DESY's setup were found agreeing with the theoretical calculation.

  12. ESO's Telescopes In memoriam Daniel Enard

    Science.gov (United States)

    Gilmozzi, Roberto

    2009-06-01

    The contributions of ESO to the art of telescope-making have come a long way since the early years, placing it, by the turn of the millennium, among the acknowledged leaders in the field. In this article I will give a brief history of what are, in my view, the highlights among these developments, from the 3.6-metre telescope through the NTT and VLT/I to the E-ELT.

  13. Indirect Dark Matter Searches with MAGIC Telescopes

    OpenAIRE

    Satalecka, Konstancja; MAGIC Collaboration

    2015-01-01

    In the last few years the indirect dark matter (DM) searches became a hot topic, with several experimental results showing hints of DM signal. The Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes are two $17$\\,m diameter Cherenkov telescopes, located on the Canary island La Palma (Spain). MAGIC carries out a broad DM search program, including observations of dwarf galaxies, galaxy clusters and other DM dominated objects. In these proceedings recent MAGIC results from this field ar...

  14. The DAG project, a 4m class telescope: the telescope main structure performances

    Science.gov (United States)

    Marchiori, G.; Busatta, A.; Ghedin, L.; Marcuzzi, E.; Manfrin, C.; Battistel, C.; Pirnay, O.; Flebus, Carlo; Yeşilyaprak, C.; Keskin, O.; Yerli, S.

    2016-07-01

    Dogu Anatolu Gözlemevi (DAG-Eastern Anatolia Observatory) Project is a 4m class optical, near-infrared Telescope and suitable enclosure which will be located at an altitude of 3.170m in Erzurum, Turkey. The DAG telescope is a project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope - ATASAM. The Project is being developed by the Belgian company AMOS (project leader), which is also the optics supplier and EIE GROUP, the Telescope Main Structure supplier and responsible for the final site integration. The design of the Telescope Main Structure fits in the EIE TBO Program which aims at developing a Dome/Telescope systemic optimization process for both performances and competitive costs based on previous project commitments like NTT, VLT, VST and ASTRI. The optical Configuration of the DAG Telescope is a Ritchey-Chretien with two Nasmyth foci and a 4m primary thin mirror controlled in shape and position by an Active Optic System. The main characteristics of the Telescope Main Structure are an Altitude-Azimuth light and rigid structure system with Direct Drive Systems for both axis, AZ Hydrostatic Bearing System and Altitude standard bearing system; both axes are equipped with Tape Encoder System. An innovative Control System characterizes the telescope performance.

  15. A Pointing Solution for the Medium Size Telescopes for the Cherenkov Telescope Array

    CERN Document Server

    Tiziani, D; Oakes, L; Schwanke, U

    2016-01-01

    An important aspect of the calibration of the Cherenkov Telescope Array is the pointing, which enables an exact alignment of each telescope and therefore allows to transform a position in the sky to a point in the plane of the Cherenkov camera and vice versa. The favoured approach for the pointing calibration of the medium size telescopes (MST) is the installation of an optical CCD-camera in the dish of the telescope that captures the position of the Cherenkov camera and of the stars in the night sky simultaneously during data taking. The adaption of this approach is presented in this proceeding.

  16. The Mercator telescope: relevance, status, and future

    Science.gov (United States)

    Raskin, Gert; Pessemier, Wim; Merges, Florian; Pérez Padilla, Jesus; Prins, Saskia; Van Winckel, Hans

    2014-07-01

    In todays era of ever growing telescope apertures, there remains a specific niche for meter-class telescopes, provided they are equipped with efficient and dedicated instruments. In case these telescopes have permanent and long-term availability, they turn out very useful for intensive monitoring campaigns over a large range of time-scales. Flexible scheduling and time allocation allow small telescopes to rapidly seize new opportunities or provide immediate follow-up observations to complement data from large ground-based or space-borne facilities. The Mercator telescope, a 1.2-m telescope, installed at the Roque de Los Muchachos Observatory on La Palma (Canary Islands, Spain), successfully targets this niche of intensive monitoring and flexible scheduling. Mercator is already in operation since 2001 and has seen several upgrades in the mean time. In this contribution we give an update about the actual telescope status and its performance. We also present the Mercator instrument suite that currently consists of two instruments. The workhorse instrument is HERMES, a very efficient and stable fibre-fed high-resolution spectrograph. Recently, the MAIA imager was commissioned. This is a three- channel photometric instrument that observes a large field simultaneously in the different color bands. The MAIA detectors are unique 6k x 2k frame transfer devices which also allow for fast and continuous monitoring of variable phenomena.We discuss two important upcoming upgrades: a long-awaited automatic mirror cover and, more importantly, an entirely new telescope control system (TCS). This TCS is based on modern PLC technology, and relies on OPC UA and EtherCAT communication. Only commercially off-the-shelve hardware will be used for controlling the telescope. As a test case and as a precursor of the full TCS, such PLC systems are already deployed at Mercator to steer the Nasmyth mirror mechanism and to control the MAIA instrument. Finally, we also give an overview of the

  17. Hosting the Student Telescope Network First Site

    Science.gov (United States)

    Rice, M.; Bisque, S. T. M. D.; Stencel, R. E.

    2002-05-01

    The demonstration site for the Student Telescope Network, and for the first practical public-use Internet observatory, as powered by iBisque software, is at New Mexico Skies in southern New Mexico (www.nmskies.com). The observatory site, located approximately 14 miles northeast of the Apache Point Observatory and the Sunspot National Solar Observatory, is at 2,225 meters elevation in the southern Sacramento Mountains of New Mexico. It has very dark transparent skies, excellent weather conditions, good seeing and a high proportion of clear photometric nights. The Internet observatory pod concept includes placing multiple telescopes (as many as twelve), in each of several 32-foot roll-off roof observatories. The 14 to 16 inch aperture telescopes, mounted on accurately pointing and tracking Bisque "Paramounts" (www.bisque.com), plus KAF-1001E CCD cameras, are controlled with a browser-based sky-map GUI (patent pending) control system also developed by Software Bisque. We provide detail on the concept and its implementation. As of mid-March, 2002, the first demonstration telescope has been operating nightly for about 60 days. Over 420 users have registered on the telescope server, more than 2,000 images have been taken and their FITS files downloaded to users' computers all over the world. In this and the companion poster, we report our experiences over the period of the February-May (2002) trial period, including technical challenges and performance measures on the Internet observatory's operations. We further detail lessons learned for future development of browser-based Internet observatories for high school/college level instructional use, and lessons applicable to the use of Internet-based telescopes for serious astronomical research as well. We thank the Institute for Connecting Science Research to the Classroom for a grant to the University of Denver in support of this Internet telescope services pilot project.

  18. New Radio Telescope Makes First Scientific Observations

    Science.gov (United States)

    2001-05-01

    The world's two largest radio telescopes have combined to make detailed radar images of the cloud-shrouded surface of Venus and of a tiny asteroid that passed near the Earth. The images mark the first scientific contributions from the National Science Foundation's (NSF) new Robert C. Byrd Green Bank Telescope in West Virginia, which worked with the NSF's recently-upgraded Arecibo telescope in Puerto Rico. The project used the radar transmitter on the Arecibo telescope and the huge collecting areas of both telescopes to receive the echoes. GBT-Arecibo Radar Image of Maxwell Montes on Venus "These images are the first of many scientific contributions to come from the Robert C. Byrd Green Bank Telescope, and a great way for it to begin its scientific career," said Paul Vanden Bout, director of the National Radio Astronomy Observatory (NRAO). "Our congratulations go to the scientists involved in this project as well as to the hard-working staffs at Green Bank and Arecibo who made this accomplishment possible," Vanden Bout added. To the eye, Venus hides behind a veil of brilliant white clouds, but these clouds can be penetrated by radar waves, revealing the planet's surface. The combination of the Green Bank Telescope (GBT), the world's largest fully-steerable radio telescope, and the Arecibo telescope, the world's most powerful radar, makes an unmatched tool for studying Venus and other solar-system bodies. "Having a really big telescope like the new Green Bank Telescope to receive the radar echoes from small asteroids that are really close to the Earth and from very distant objects like Titan, the large moon of Saturn, will be a real boon to radar studies of the solar system." said Cornell University professor Donald Campbell, leader of the research team. Ten years ago, the radar system on NASA's Magellan spacecraft probed though the clouds of Venus to reveal in amazing detail the surface of the Earth's twin planet. These new studies using the GBT and Arecibo, the

  19. Undergraduate Research with a Small Radio Telescope

    Science.gov (United States)

    Fisher, P. L.; Williams, G. J.

    2001-11-01

    We describe the construction of a small radio telescope system at ULM and the role of radio astronomy in undergraduate education. The heart of the system is the Small Radio Telescope (SRT), which is a modified satellite TV antenna and custom receiver purchased from MIT Haystack Observatory. This telescope measures the brightness of many celestial objects at wavelengths near 21 cm. The system consists of various components to control dish movement, as well as perform analog to digital conversions allowing analysis of collected data. Undergraduate students have participated in the construction of the hardware and the task of interfacing the hardware to software on two GNU/Linux computer systems. The construction of the telescope and analysis of data allow the students to employ key concepts from mechanics, optics, electrodynamics, and thermodynamics, as well as computer and electronics skills. We will report preliminary results of solar observations conducted with this instrument and with the MIT Haystack Observatory 37m radio telescope. This work was supported by Louisiana Board of Regents grant LEQSF-ENH-UG-16, NASA/LaSPACE LURA R109139 and ULM Development Foundation Grant 97317.

  20. Simulation and track reconstruction for beam telescopes

    CERN Document Server

    Maqbool, Salman

    2017-01-01

    Beam telescopes are used for testing new detectors under development. Sensors are placed and a particle beam is passed through them. To test these novel detectors and determine their properties, the particle tracks need to be reconstructed from the known detectors in the telescope. Based on the reconstructed track, it’s predicted hits on the Device under Test (DUT) are compared with the actual hits on the DUT. Several methods exist for track reconstruction, but most of them don’t account for the effects of multiple scattering. General Broken Lines is one such algorithm which incorporates these effects during reconstruction. The aim of this project was to simulate the beam telescope and extend the track reconstruction framework for the FE-I4 telescope, which takes these effects into account. Section 1 introduces the problem, while section 2 focuses on beam telescopes. This is followed by the Allpix2 simulation framework in Section 3. And finally, Section 4 introduces the Proteus track reconstruction framew...

  1. Control challenges for extremely large telescopes

    Science.gov (United States)

    MacMartin, Douglas G.

    2003-08-01

    The next generation of large ground-based optical telescopes are likely to involve a highly segmented primary mirror that must be controlled in the presence of wind and other disturbances, resulting in a new set of challenges for control. The current design concept for the California Extremely Large Telescope (CELT) includes 1080 segments in the primary mirror, with the out-of-plane degrees of freedom actively controlled. In addition to the 3240 primary mirror actuators, the secondary mirror of the telescope will also require at least 5 degree of freedom control. The bandwidth of both control systems will be limited by coupling to structural modes. I discuss three control issues for extremely large telescopes in the context of the CELT design, describing both the status and remaining challenges. First, with many actuators and sensors, the cost and reliability of the control hardware is critical; the hardware requirements and current actuator design are discussed. Second, wind buffeting due to turbulence inside the telescope enclosure is likely to drive the control bandwidth higher, and hence limitations resulting from control-structure-interaction must be understood. Finally, the impact on the control architecture is briefly discussed.

  2. Introduction to the Chinese Giant Solar Telescope

    Science.gov (United States)

    Liu, Z.; Deng, Y.; Ji, H.

    2012-12-01

    In order to detect the fine structures of solar magnetic field and dynamic field, an 8 meter solar telescope has been proposed by Chinese solar community. Due to the advantages of ring structure in polarization detection and thermal control, the current design of CGST (Chinese Giant Solar Telescope) is an 8 meter ring solar telescope. The spatial resolution of CGST is equivalent to an 8 meter diameter telescope, and the light-gathering power equivalent to a 5 meter full aperture telescope. The integrated simulation of optical system and imaging ability such as optical design, MCAO, active maintenance of primary mirror were carried out in this paper. Mechanical system was analyzed by finite element method too. The results of simulation and analysis showed that the current design could meet the demand of most science cases not only in infrared band but also in near infrared band and even in visible band. CGST was proposed by all solar observatories in Chinese Academy of Sciences and several overseas scientists. It is supported by CAS (Chinese Academy of Sciences) and NSFC (National Natural Science Foundation of China) as a long term astronomical project.

  3. Habitable Exoplanet Imager Optical Telescope Concept Design

    Science.gov (United States)

    Stahl, H Philip

    2017-01-01

    The Habitable Exoplanet Imaging Mission (HabEx) is one of four missions under study for the 2020 Astrophysics Decadal Survey. Its goal is to directly image and spectroscopically characterize planetary systems in the habitable zone of Sun-like stars. Additionally, HabEx will perform a broad range of general astrophysics science enabled by 100 to 2500 nm spectral range and 3 x 3 arc-minute FOV. Critical to achieving the HabEx science goals is a large, ultra-stable UV/Optical/Near-IR (UVOIR) telescope. The baseline HabEx telescope is a 4-meter off-axis unobscured three-mirror-anastigmatic, diffraction limited at 400 nm with wavefront stability on the order of a few 10s of picometers. This paper summarizes the opto-mechanical design of the HabEx baseline optical telescope assembly, including a discussion of how science requirements drive the telescope's specifications, and presents analysis that the baseline telescope structure meets its specified tolerances.

  4. The Telescope: Outline of a Poetic History

    Science.gov (United States)

    Stocchi, M. P.

    2011-06-01

    Amongst the first editions of Galileo's books, only the Saggiatore has on its frontispiece the image of the telescope. Indeed, the telescope is not pictured on the very emphatic frontispieces of the other books in which Galileo was presenting and defending the results achieved by his celestial observations, such as the Sidereus Nuncius. Many contemporary scientists denied the reliability of the telescope, and some even refused to look into the eyepiece. In the 16th and 17th century, the lenses, mirrors, and optical devices of extraordinary complexity did not have the main task of leading to the objective truth but obtaining the deformation of the reality by means of amazing effects of illusion. The Baroque art and literature had the aim of surprising, and the artists gave an enthusiastic support to the telescope. The poems in praise of Galileo's telescopic findings were quite numerous, including Adone composed by Giovanni Battista Marino, one of the most renowned poets of the time. The Galilean discoveries were actually accepted by the poets as ideologically neutral contributions to the "wonder" in spite they were rejected or even condemned by the scientists, philosophers, and theologians.

  5. Schwarzschild-Couder telescope for the Cherenkov Telescope Array: Development of the Optical System

    CERN Document Server

    Rousselle, Julien; Errando, Manel; Humensky, Brian; Mukherjee, Reshmi; Nieto, Daniel; Okumura, Akira; Vassiliev, Vladimir

    2013-01-01

    The CTA (Cherenkov Telescope Array) is the next generation ground-based experiment for very high-energy (VHE) gamma-ray observations. It will integrate several tens of imaging atmospheric Cherenkov telescopes (IACTs) with different apertures into a single astronomical instrument. The US part of the CTA collaboration has proposed and is developing a novel IACT design with a Schwarzschild-Couder (SC) aplanatic two mirror optical system. In comparison with the traditional single mirror Davies-Cotton IACT the SC telescope, by design, can accommodate a wide field-of-view, with significantly improved imaging resolution. In addition, the reduced plate scale of an SC telescope makes it compatible with highly integrated cameras assembled from silicon photo multipliers. In this submission we report on the status of the development of the SC optical system, which is part of the effort to construct a full-scale prototype telescope of this type at the Fred Lawrence Whipple Observatory in southern Arizona.

  6. Single-Mirror Small-Size Telescope structure for the Cherenkov Telescope Array

    CERN Document Server

    Niemiec, Jacek; Dyrda, Michał; Kochański, Wojciech; Ludwin, Jaromir; Stodulski, Marek; Ziółkowski, Paweł

    2013-01-01

    A single-mirror small-size (1M-SST) Davies-Cotton telescope has been proposed for the southern observatory of the Cherenkov Telescope Array (CTA) by a consortium of scientific institutions from Poland, Switzerland, and Germany. The telescope has a 4 m diameter reflector and will be equipped with a fully digital camera based on Geiger avalanche photodiodes (APDs). Such a design is particularly interesting for CTA because it represents a very simple, reliable, and cheap solution for a SST. Here we present the design and the characteristics of the mechanical structure of the 1M-SST telescope and its drive system. We also discuss the results of a finite element method analysis in order to demonstrate the conformance of the design with the CTA specifications and scientific objectives. In addition, we report on the current status of the construction of a prototype telescope structure at the Institute of Nuclear Physics PAS in Krakow.

  7. The Cherenkov Telescope Array single-mirror small size telescope project: status and prospects

    Science.gov (United States)

    Aguilar, J. A.; Bilnik, W.; Bogacz, L.; Bulik, T.; Christov, A.; della Volpe, D.; Dyrda, M.; Frankowski, A.; Grudzińska, M.; Grygorczuk, J.; Heller, M.; Idźkowski, B.; Janiak, M.; Jamrozy, M.; Karczewski, M.; Kasperek, J.; Lyard, E.; Marszalek, A.; Michalowski, J.; Rameez, M.; Moderski, R.; Montaruli, T.; Neronov, A.; Nicolau-Kukliński, J.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Płatos, Ł.; Prandini, E.; Rafalski, J.; Rajda, P. J.; Rataj, M.; Rupiński, M.; Rutkowskai, K.; Seweryn, K.; Sidz, M.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Tokarz, M.; Toscano, S.; Troyano Pujadas, I.; Walter, R.; Wawer, P.; Wawrzaszek, R.; Wiśniewski, L.; Winiarski, K.; Zietara, K.; Ziółkowski, P.; Źychowski, P.

    2014-07-01

    The Cherenkov Telescope Array (CTA), the next generation very high energy gamma-ray observatory, will consist of three types of telescopes: large (LST), medium (MST) and small (SST) size telescopes. The small size telescopes are dedicated to the observation of gamma-rays with energy between a few TeV and few hundreds of TeV. The single-mirror small size telescope (SST-1M) is one of several SST designs. It will be equipped with a 4 m-diameter segmented mirror dish and a fully digital camera based on Geiger-mode avalanche photodiodes. Currently, the first prototype of the mechanical structure is under assembly in Poland. In 2014 it will be equipped with 18 mirror facets and a prototype of the camera.

  8. Status of the Schwarzchild-Couder Medium-Sized Telescope for the Cherenkov Telescope Array

    CERN Document Server

    Benbow, W

    2016-01-01

    The Cherenkov Telescope Array (CTA) is planned to be the next-generation very-high-energy (VHE; E > 100 GeV) gamma-ray observatory. It is anticipated that CTA will improve upon the sensitivity of the current generation of VHE experiments, such as VERITAS, HESS and MAGIC, by an order of magnitude. CTA is planned to consist of two graded arrays of Cherenkov telescopes with three primary-mirror sizes. A proof-of-concept telescope, based on the dual-mirror Schwarzchild-Couder design, is being constructed on the VERITAS site at the F.L. Whipple Observatory in southern Arizona, USA, and is a candidate design for the medium-sized telescopes. The construction of the telescope will be completed in early 2017, and the status of this project is presented here.

  9. An innovative telescope control system architecture for SST-GATE telescopes at the CTA Observatory

    Science.gov (United States)

    Fasola, Gilles; Mignot, Shan; Laporte, Philippe; Abchiche, Abdel; Buchholtz, Gilles; Jégouzo, Isabelle

    2014-07-01

    SST-GATE (Small Size Telescope - GAmma-ray Telescope Elements) is a 4-metre telescope designed as a prototype for the Small Size Telescopes (SST) of the Cherenkov Telescope Array (CTA), a major facility for the very high energy gamma-ray astronomy of the next three decades. In this 100-telescope array there will be 70 SSTs, involving a design with an industrial view aiming at long-term service, low maintenance effort and reduced costs. More than a prototype, SST-GATE is also a fully functional telescope that shall be usable by scientists and students at the Observatoire de Meudon for 30 years. The Telescope Control System (TCS) is designed to work either as an element of a large array driven by an array controller or in a stand-alone mode with a remote workstation. Hence it is built to be autonomous with versatile interfacing; as an example, pointing and tracking —the main functions of the telescope— are managed onboard, including astronomical transformations, geometrical transformations (e.g. telescope bending model) and drive control. The core hardware is a CompactRIO (cRIO) featuring a real-time operating system and an FPGA. In this paper, we present an overview of the current status of the TCS. We especially focus on three items: the pointing computation implemented in the FPGA of the cRIO —using CORDIC algorithms— since it enables an optimisation of the hardware resources; data flow management based on OPCUA with its specific implementation on the cRIO; and the use of an EtherCAT field-bus for its ability to provide real-time data exchanges with the sensors and actuators distributed throughout the telescope.

  10. Nearby Exo-Earth Astrometric Telescope (NEAT)

    Science.gov (United States)

    Shao, M.; Nemati, B.; Zhai, C.; Goullioud, R.

    2011-01-01

    NEAT (Nearby Exo ]Earths Astrometric Telescope) is a modest sized (1m diameter telescope) It will be capable of searching approx 100 nearby stars down to 1 Mearth planets in the habitable zone, and 200 @ 5 Mearth, 1AU. The concept addresses the major issues for ultra -precise astrometry: (1) Photon noise (0.5 deg dia field of view) (2) Optical errors (beam walk) with long focal length telescope (3) Focal plane errors , with laser metrology of the focal plane (4) PSF centroiding errors with measurement of the "True" PSF instead of using a "guess " of the true PSF, and correction for intra pixel QE non-uniformities. Technology "close" to complete. Focal plane geometry to 2e-5 pixels and centroiding to approx 4e -5 pixels.

  11. The University of Iowa Automated Telescope Facility

    Science.gov (United States)

    Downey, E. C.; Mutel, R. L.

    We describe a CCD-based automated telescope system in operation at the University of Iowa. Observers initiate observing programs using a simple free-format scripting language for preparing observing requests. The schedule file describes sources, durations, filters and other observing parameters. A telescope scheduling program generates an ordered master observing list for a given night based on priority telescope control daemon then reads the sorted schedule file and issues commands to the hardware control daemons. All CCD images are calibrated (bias, thermal, flat) by default and pattern matched to the Guide Star Catalog, with accurate WCS coordinates written to the FITS header. Additional post-processing tools include an interactive image display and analysis program which supports photometry and astrometry, batch tools to automate supernova searches and time-sequenced photometry, and a stand-alone world coordinate calibration tool. Additional details are available {http://inferno.physics.uiowa.edu} on the WWW.

  12. Accurate Telescope Mount Positioning with MEMS Accelerometers

    Science.gov (United States)

    Mészáros, L.; Jaskó, A.; Pál, A.; Csépány, G.

    2014-08-01

    This paper describes the advantages and challenges of applying microelectromechanical accelerometer systems (MEMS accelerometers) in order to attain precise, accurate and stateless positioning of telescope mounts. This provides a completely independent method from other forms of electronic, optical, mechanical or magnetic feedback or real-time astrometry. Our goal is to reach the sub-arcminute range which is well smaller than the field-of-view of conventional imaging telescope systems. Here we present how this sub-arcminute accuracy can be achieved with very cheap MEMS sensors and we also detail how our procedures can be extended in order to attain even finer measurements. In addition, our paper discusses how can a complete system design be implemented in order to be a part of a telescope control system.

  13. LOBSTER - New Space X-Ray telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Hudec, R. [Astronomical Institute, Academy of Sciences of the Czech Republic, CZ-251 65 Ondrejov (Czech Republic); Pina, L. [Faculty of Nuclear Science, Czech Technical University, Prague (Czech Republic); Simon, V. [Astronomical Institute, Academy of Sciences of the Czech Republic, CZ-251 65 Ondrejov (Czech Republic); Sveda, L. [Faculty of Nuclear Science, Czech Technical University, Prague (Czech Republic); Inneman, A.; Semencova, V. [Center for Advanced X-ray Technologies, Reflex, Prague (Czech Republic); Skulinova, M. [Astronomical Institute, Academy of Sciences of the Czech Republic, CZ-251 65 Ondrejov (Czech Republic)

    2007-04-15

    We discuss the technological and scientific aspects of fully innovative very wide-field X-ray telescopes with high sensitivity. The prototypes of Lobster telescopes designed, developed and tested are very promising, allowing the proposals for space projects with very wide-field Lobster Eye X-ray optics to be considered for the first time. The novel telescopes will monitor the sky with unprecedented sensitivity and angular resolution of order of 1 arcmin. They are expected to contribute essentially to study of various astrophysical objects such as AGN, SNe, Gamma-ray bursts (GRBs), X-ray flashes (XRFs), galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc. For example, the Lobster optics based X-ray All Sky Monitor is capable to detect around 20 GRBs and 8 XRFs yearly and this will surely significantly contribute to the related science.

  14. Adaptive Real Time Imaging Synthesis Telescopes

    CERN Document Server

    Wright, Melvyn

    2012-01-01

    The digital revolution is transforming astronomy from a data-starved to a data-submerged science. Instruments such as the Atacama Large Millimeter Array (ALMA), the Large Synoptic Survey Telescope (LSST), and the Square Kilometer Array (SKA) will measure their accumulated data in petabytes. The capacity to produce enormous volumes of data must be matched with the computing power to process that data and produce meaningful results. In addition to handling huge data rates, we need adaptive calibration and beamforming to handle atmospheric fluctuations and radio frequency interference, and to provide a user environment which makes the full power of large telescope arrays accessible to both expert and non-expert users. Delayed calibration and analysis limit the science which can be done. To make the best use of both telescope and human resources we must reduce the burden of data reduction. Our instrumentation comprises of a flexible correlator, beam former and imager with digital signal processing closely coupled...

  15. New Concept of Hungarian Robotic Telescopes

    Science.gov (United States)

    Hegedus, T.; Kiss, Z.; Biro, B.; Jager, Z.

    As the result of a longer innovation of a few Hungarian opto-mechanical and electronic small companies, a concept of fully robotic mounts has been formed some years ago. There are lots of Hungarian Automated Telescopes over the world (in Arizona, South Korea, Izrael and atop Mauna Kea, just below the famous Keck domes). These are cited as HAT telescopes (Bakos et al. 2002), and served thousands of large-frame time-series CCD images since 2004, and the working team found already 6 exoplanets, and a number of new variable stars, etc... The newest idea was to build a more robust robotic mount, hosting larger optics (D > 50 cm) for achieving much fainter celestial objects, than the HAT series (they are operating with Nikon teleobjective lenses) on a still relatively wide celestial area. The very first sample model is the BART-1, a 50cm f/6 telescope.

  16. Mirror Development for the Cherenkov Telescope Array

    CERN Document Server

    Förster, A; Baba, H; Bähr, J; Bonardi, A; Bonnoli, G; Brun, P; Canestrari, R; Chadwick, P; Chikawa, M; Carton, P -H; De Souza, V; Dipold, J; Doro, M; Durand, D; Dyrda, M; Giro, E; Glicenstein, J -F; Hanabata, Y; Hayashida, M; Hrabovski, M; Jeanney, C; Kagaya, M; Katagiri, H; Lessio, L; MANDAT, D; Mariotti, M; Medina, C; Michałowski, J; Micolon, P; Nakajima, D; Niemiec, J; Nozato, A; Palatka, M; Pareschi, G; Pech, M; Peyaud, B; Pühlhofer, G; Rataj, M; Rodeghiero, G; Rojas, G; Rousselle, J; Sakonaka, R; Schovanek, P; Seweryn, K; Schultz, C; Shu, S; Stinzing, F; Stodulski, M; Teshima, M; Travniczek, P; Van Eldik, C; Vassiliev, V; Wiśniewski, Ł; Wörnlein, A; Yoshida, T

    2013-01-01

    The Cherenkov Telescope Array (CTA) is a planned observatory for very-high energy gamma-ray astronomy. It will consist of several tens of telescopes of different sizes, with a total mirror area of up to 10,000 square meters. Most mirrors of current installations are either polished glass mirrors or diamond-turned aluminium mirrors, both labour intensive technologies. For CTA, several new technologies for a fast and cost-efficient production of light-weight and reliable mirror substrates have been developed and industrial pre-production has started for most of them. In addition, new or improved aluminium-based and dielectric surface coatings have been developed to increase the reflectance over the lifetime of the mirrors compared to those of current Cherenkov telescope instruments.

  17. GREGOR: the New German Solar Telescope

    CERN Document Server

    Balthasar, H; Kneer, F; Staude, J; Volkmer, R; Berkefeld, T; Caligari, P; Collados, M; Halbgewachs, C; Heidecke, F; Hofmann, A; Klvana, M; Nicklas, H; Popow, E; Puschmann, K; Schmidt, W; Sobotka, M; Soltau, D; Strassmeier, K; Wittmann, A

    2007-01-01

    GREGOR is a new open solar telescope with an aperture of 1.5m. It replaces the former 45-cm Gregory Coude telescope on the Canary island Tenerife. The optical concept is that of a double Gregory system. The main and the elliptical mirrors are made from a silicon-carbide material with high thermal conductivity. This is important to keep the mirrors on the ambient temperature avoiding local turbulence. GREGOR will be equipped with an adaptive optics system. The new telescope will be ready for operation in 2008. Post-focus instruments in the first stage will be a spectrograph for polarimetry in the near infrared and a 2-dimensional spectrometer based on Fabry-Perot interferometers for the visible.

  18. Telescopic nanotube device for hot nanolithography

    Science.gov (United States)

    Popescu, Adrian; Woods, Lilia M

    2014-12-30

    A device for maintaining a constant tip-surface distance for producing nanolithography patterns on a surface using a telescopic nanotube for hot nanolithography. An outer nanotube is attached to an AFM cantilever opposite a support end. An inner nanotube is telescopically disposed within the outer nanotube. The tip of the inner nanotube is heated to a sufficiently high temperature and brought in the vicinity of the surface. Heat is transmitted to the surface for thermal imprinting. Because the inner tube moves telescopically along the outer nanotube axis, a tip-surface distance is maintained constant due to the vdW force interaction, which in turn eliminates the need of an active feedback loop.

  19. The SPIRIT Telescope Initiative: six years on

    Science.gov (United States)

    Luckas, Paul

    2017-06-01

    Now in its sixth year of operation, the SPIRIT initiative remains unique in Australia, as a robust web-enabled robotic telescope initiative funded for education and outreach. With multiple modes of operation catering for a variety of usage scenarios and a fully supported education program, SPIRIT provides free access to contemporary astronomical tools for students and educators in Western Australia and beyond. The technical solution itself provides an excellent model for low cost robotic telescope installations, and the education program has evolved over time to include a broad range of student experiences-from engagement activities to authentic science. This paper details the robotic telescope solution, student interface and educational philosophy, summarises achievements and lessons learned and examines the possibilities for future enhancement including spectroscopy.

  20. MROI Array telescopes: the relocatable enclosure domes

    Science.gov (United States)

    Marchiori, G.; Busatta, A.; Payne, I.

    2016-07-01

    The MROI - Magdalena Ridge Interferometer is a project which comprises an array of up to 10 1.4m diameter mirror telescopes arranged in a "Y" configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. EIE GROUP Srl, Venice - Italy, was awarded the contract for the design, the construction and the erection on site of the MROI by the New Mexico Institute of Mining and Technology. The close-pack array of the MROI - including all 10 telescopes, several of which are at a relative distance of less than 8m center to center from each other - necessitated an original design for the Unit Telescope Enclosure (UTE). This innovative design enclosure incorporates a unique dome/observing aperture system to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). The main characteristics of this Relocatable Enclosure Dome are: a Light insulated Steel Structure with a dome made of composites materials (e.g. glass/carbon fibers, sandwich panels etc.), an aperture motorized system for observation, a series of louvers for ventilation, a series of electrical and plants installations and relevant auxiliary equipment. The first Enclosure Dome is now under construction and the completion of the mounting on site id envisaged by the end of 2016. The relocation system utilizes a modified reachstacker (a transporter used to handle freight containers) capable of maneuvering between and around the enclosures, capable of lifting the combined weight of the enclosure with the telescope (30tons), with minimal impacts due to vibrations.

  1. The ANTARES telescope neutrino alert system

    Science.gov (United States)

    Ageron, M.; Aguilar, J. A.; Al Samarai, I.; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J.-J.; Baret, B.; Basa, S.; Bertin, V.; Biagi, S.; Bigi, A.; Bigongiari, C.; Bogazzi, C.; Bou-Cabo, M.; Bouhou, B.; Bouwhuis, M. C.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Cârloganu, C.; Carminati, G.; Carr, J.; Cecchini, S.; Charif, Z.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Coniglione, R.; Costantini, H.; Coyle, P.; Curtil, C.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drouhin, D.; Eberl, T.; Emanuele, U.; Enzenhöfer, A.; Ernenwein, J.-P.; Escoffier, S.; Fermani, P.; Ferri, M.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J.-L.; Galatà, S.; Gay, P.; Giacomelli, G.; Giordano, V.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Hartman, J.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; Hsu, C. C.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U.; Kavatsyuk, O.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lattuada, D.; Lefèvre, D.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martínez-Mora, J. A.; Meli, A.; Montaruli, T.; Moscoso, L.; Motz, H.; Neff, M.; Nezri, E.; Palioselitis, D.; Păvălaş, G. E.; Payet, K.; Payre, P.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Reed, C.; Richardt, C.; Richter, R.; Rivière, C.; Robert, A.; Roensch, K.; Rostovtsev, A.; Ruiz-Rivas, J.; Rujoiu, M.; Russo, G. V.; Salesa, F.; Sapienza, P.; Schöck, F.; Schuller, J.-P.; Schüssler, F.; Shanidze, R.; Simeone, F.; Spies, A.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Sánchez-Losa, A.; Taiuti, M.; Tamburini, C.; Toscano, S.; Vallage, B.; van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; Wilms, J.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.

    2012-03-01

    The ANTARES telescope has the capability to detect neutrinos produced in astrophysical transient sources. Potential sources include gamma-ray bursts, core collapse supernovae, and flaring active galactic nuclei. To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated for special events, such as two or more neutrinos, coincident in time and direction, or single neutrinos of very high energy.

  2. The ANTARES Telescope Neutrino Alert System

    CERN Document Server

    Ageron, M; Samarai, I Al; Albert, A; André, M; Anghinolfi, M; Anton, G; Anvar, S; Ardid, M; Jesus, A C Assis; Astraatmadja, T; Aubert, J-J; Baret, B; Basa, S; Bertin, V; Biagi, S; Bigi, A; Bigongiari, C; Bogazzi, C; Bou-Cabo, M; Bouhou, B; Bouwhuis, M C; Brunner, J; Busto, J; Camarena, F; Capone, A; Cârloganu, C; Carminati, G; Carr, J; Cecchini, S; Charif, Z; Charvis, Ph; Chiarusi, T; Circella, M; Coniglione, R; Costantini, H; Coyle, P; Curtil, C; Decowski, M P; Dekeyser, I; Deschamps, A; Distefano, C; Donzaud, C; Dornic, D; Dorosti, Q; Drouhin, D; Eberl, T; Emanuele, U; Enzenöfer, A; Ernenwein, J-P; Escoffier, S; Fermani, P; Ferri, M; Flaminio, V; Folger, F; Fritsch, U; Fuda, J-L; Galatà, S; Gay, P; Giacomelli, G; Giordano, V; Gòmez-González, J; Graf, K; Guillard, G; Halladjian, G; Hallewell, G; van Haren, H; Hartman, J; Heijboer, A J; Hello, Y; Hernández-Rey, J J; Herold, B; Hößl, J; Hsu, C C; de Jong, M; Kadler, M; Kalekin, O; Kappes, A; Katz, U; Kavatsyuk, O; Kooijman, P; Kopper, C; Kouchner, A; Kreykenbohm, I; Kulikovskiy, V; Lahmann, R; Lamar, P; Larosa, G; Lattuada, D; Lefèvre, D; Lim, G; Presti, D Lo; Loehner, H; Loucatos, S; Mangano, S; Marcelin, M; Margiotta, A; Martínez-Mora, J A; Meli, A; Montaruli, T; Moscoso, L; Motz, H; Neff, M; Nezri, E; Palioselitis, D; Păvălaş, G E; Payet, K; Payre, P; Petrovic, J; Piattelli, P; Picot-Clemente, N; Popa, V; Pradier, T; Presani, E; Racca, C; Reed, C; Richardt, C; Richter, R; Rivière, C; Robert, A; Roensch, K; Rostovtsev, A; Ruiz-Rivas, J; Rujoiu, M; Russo, G V; Salesa, F; Sapienza, P; Schöck, F; Schuller, J-P; Schüssler, F; Shanidze, R; Simeone, F; Spies, A; Spuriol, M; Steijger, J J M; Stolarczyk, Th; Sànchez-Losa, A; Taiuti, M; Tamburini, C; Toscano, S; Vallage, B; Van Elewyck, V; Vannoni, G; Vecchi, M; Vernin, P; Wijnker, G; Wilms, J; de Wolf, E; Yepes, H; Zaborov, D; Zornoza, J D; Zùñiga, J

    2011-01-01

    The ANTARES telescope has the capability to detect neutrinos produced in astrophysical transient sources. Potential sources include gamma-ray bursts, core collapse supernovae, and flaring active galactic nuclei. To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated for special events, such as two or more neutrinos, coincident in time and direction, or single neutrinos of very high energy.

  3. The 10 Meter South Pole Telescope

    OpenAIRE

    Carlstrom, J. E.; Ade, P. A. R.; Aird, K. A.; Benson, B. A.; Bleem, L. E.; Busetti, S.; Chang, C. L.; Chauvin, E; Cho, H. -M.; Crawford, T. M.; Crites, A. T.; Dobbs, M. A.; Halverson, N. W.; Heimsath, S.; Holzapfel, W. L.

    2009-01-01

    The South Pole Telescope (SPT) is a 10 m diameter, wide-field, offset Gregorian telescope with a 966-pixel, multi-color, millimeter-wave, bolometer camera. It is located at the Amundsen-Scott South Pole station in Antarctica. The design of the SPT emphasizes careful control of spillover and scattering, to minimize noise and false signals due to ground pickup. The key initial project is a large-area survey at wavelengths of 3, 2 and 1.3 mm, to detect clusters of galaxies via the Sunyaev-Zeldov...

  4. Autonomous Dome for a Robotic Telescope

    Science.gov (United States)

    Kumar, A.; Sengupta, A.; Ganesh, S.

    2016-12-01

    The Physical Research Laboratory operates a 50 cm robotic observatory at Mount Abu (Rajsthan, India). This Automated Telescope for Variability Studies (ATVS) makes use of the Remote Telescope System 2 (RTS2) for autonomous operations. The observatory uses a 3.5 m dome from Sirius Observatories. We have developed electronics using Arduino electronic circuit boards with home grown logic and software to control the dome operations. We are in the process of completing the drivers to link our Arduino based dome controller with RTS2. This document is a short description of the various phases of the development and their integration to achieve the required objective.

  5. SOAR Telescope seismic performance II: seismic mitigation

    Science.gov (United States)

    Elias, Jonathan H.; Muñoz, Freddy; Warner, Michael; Rivera, Rossano; Martínez, Manuel

    2016-07-01

    We describe design modifications to the SOAR telescope intended to reduce the impact of future major earthquakes, based on the facility's experience during recent events, most notably the September 2015 Illapel earthquake. Specific modifications include a redesign of the encoder systems for both azimuth and elevation, seismic trigger for the emergency stop system, and additional protections for the telescope secondary mirror system. The secondary mirror protection may combine measures to reduce amplification of seismic vibration and "fail-safe" components within the assembly. The status of these upgrades is presented.

  6. Weizmann Fast Astronomical Survey Telescope (WFAST)

    Science.gov (United States)

    Nir, Guy; Ofek, Eran Oded; Ben-Ami, Sagi; Manulis, Ilan; Gal-Yam, Avishay; Diner, Oz; Rappaport, Michael

    2017-01-01

    The Weizmann Fast Astronomical Survey Telescope (W-FAST) is an experiment designed to explore variability on sub-second time scales. When completed it will consist of two robotic 55-cm f/2 Schmidt telescopes. The optics is capable of providing $\\sim0.5$" image quality over 23 deg$^2$. The focal plane will be equipped with fast readout, low read-noise sCMOS detectors. The first generation focal plane is expected to have 6.2 deg$^2$ field of view. WFAST is designed to study occultations by solar system objects (KBOs and Oort cloud objects), short time scale stellar variability, and high resolution imaging via proper coaddition.

  7. Recent Results from the ANTARES Neutrino Telescope

    CERN Document Server

    Giacomelli, Giorgio

    2012-01-01

    The ANTARES underwater neutrino telescope is located in the Mediterranean Sea about 40 km from Toulon at a depth of 2475 m. In its 12 line configuration it has almost 900 photomultipliers in 295 floors. The performance of the detector is discussed and several results are presented, including the measurements of downgoing muons, atmospheric neutrinos, search for a diffuse flux of high energy muon neutrinos, search for cosmic point sources of neutrinos, multi messenger astronomy, searches for fast magnetic monopoles and slow nuclearites. A short discussion is also made on Earth and Sea Science studies with a neutrino telescope.

  8. Daniel K. Inouye Solar Telescope Science Operations

    Science.gov (United States)

    Tritschler, Alexandra; Rimmele, Thomas R.; Berukoff, Steven

    2016-05-01

    The Daniel K. Inouye Solar Telescope (DKIST) is a versatile high resolution ground-based solar telescope designed to explore the dynamic Sun and its magnetism throughout the solar atmosphere from the photosphere to the faint corona. The DKIST is currently under construction on Haleakala, Maui, Hawai'i, and expected to commence with science operations in 2019. In this contribution we provide an overview of the high-level science operations concepts from proposal preparation and submission to the flexible and dynamic planning and execution of observations.

  9. Telescope Bernard Lyot: operation, instrumentation, perspectives

    Science.gov (United States)

    Cabanac, R.

    2016-12-01

    This talk is the TBL director report at the 3rd French national telescopes Users Meeting of 2016. Telescope Bernard Lyot, the 2-m at Pic du midi (2870m), is dedicated to spectro-polarimetric studies since 2007 with the instrument Narval. This paper presents TBL operation, science highlights and statistics of the past 10 years of operation. It also opens perspectives for the coming 10 years with the funding of Neo-Narval (Narval stabilized to v_r Pic du midi (aka SPIP) for the study of the young exoplanetary systems.

  10. Lunar Ultraviolet Telescope Experiment (LUTE) overview

    Science.gov (United States)

    McBrayer, R. O.; Frazier, J.; Nein, M.

    1993-09-01

    The Lunar Ultraviolet Telescope Experiment (LUTE) is a 1-m aperture telescope for imaging the stellar ultraviolet spectrum from the lunar surface. The aspects of Lute's educational value and the information it can provide on designing for the long-term exposure to the lunar environment are important considerations. This paper briefly summarizes the status of the phase A study by the Marshall Space Flight Center's (MSFC) LUTE Task Team. The primary focus will be a discussion of the merits of LUTE as a small and relatively inexpensive project that benefits a wide spectrum of interests and could be operating on the lunar surface by the turn of the century.

  11. 4 m Davies-Cotton telescope for the Cherenkov Telescope Array

    CERN Document Server

    Moderski, R; Barnacka, A; Basili, A; Boccone, V; Bogacz, L; Cadoux, F; Christov, A; Della Volpe, M; Dyrda, M; Frankowski, A; Grudzińska, M; Janiak, M; Karczewski, M; Kasperek, J; Kochański, W; Korohoda, P; Kozioł, J; Lubiński, P; Ludwin, J; Lyard, E; Marszałek, A; Michałowski, J; Montaruli, T; Nicolau-Kukliński, J; Niemiec, J; Ostrowski, M; Płatos, Ł; Rajda, P J; Rameez, M; Romaszkan, W; Rupiński, M; Seweryn, K; Stodulska, M; Stodulski, M; Walter, R; Winiarski, K; Wiśniewski, Ł; Zagdański, A; Zietara, K; Ziółkowski, P; Żychowski, P

    2013-01-01

    The Cherenkov Telescope Array (CTA) is the next generation very high energy gamma-ray observatory. It will consist of three classes of telescopes, of large, medium and small sizes. The small telescopes, of 4 m diameter, will be dedicated to the observations of the highest energy gamma-rays, above several TeV. We present the technical characteristics of a single mirror, 4 m diameter, Davies-Cotton telescope for the CTA and the performance of the sub-array consisting of the telescopes of this type. The telescope will be equipped with a fully digital camera based on custom made, hexagonal Geiger-mode avalanche photodiodes. The development of cameras based on such devices is an RnD since traditionally photomultipliers are used. The photodiodes are now being characterized at various institutions of the CTA Consortium. Glass mirrors will be used, although an alternative is being considered: composite mirrors that could be adopted if they meet the project requirements. We present a design of the telescope structure,...

  12. Revisiting the Effectiveness of Large Optical Telescopes

    Directory of Open Access Journals (Sweden)

    V. V. Sychev

    2015-01-01

    Full Text Available To create large-size optical telescopes, various design concepts have been used. Each concept inevitably faced the challenge to optimize technical characteristics and parameters of the telescope. There was always a question: what concept to choose, how to estimate efficiency of such telescopes and by what criteria and how to estimate expediency of this or that project of the large-size telescope. It is, obviously, insufficient to make a resolution-based estimation. An estimate by the angular field size is inappropriate too. Well, it may be also an estimate by the stellar magnitude. All these criteria are related to each other. Improvement of one of these parameters inevitably leads to deterioration of the others. Obviously, the certain generalized criterion considering all parameters and features of the design concept of the large-size telescope is necessary here. As such can serve the criterion of informational content of the telescope.The article offers a complex criterion allowing not only to estimate efficiency of large-size optical telescopes, but also to compare their conceptual and technological level among themselves in terms of obtaining information.The article suggests a new term, i.e. the informational content invariant to characterize informative capacities of the chosen concept and of the realizing technology. It will allow us to avoid unjustified complications of technical solutions, wrong accents in designing and excess material inputs when developing the project.The informational content criterion-based analysis of the existing projects of large-size telescopes has been convincingly shown that, conceptually, there are three best telescopes, namely: GSMT, CELT, and ACT-25. And, in terms of informational content, the АCТ-25 is 10 times more than GSMT and CELT, and the existing Keck-telescope exceeds by 30 times. Hence, it is hard to escape a conclusion that it is more favourable to implement one ACT-25, than to do 10 GSMT or CELT

  13. Prototype of the SST-1M Telescope Structure for the Cherenkov Telescope Array

    CERN Document Server

    Niemiec, J; Błocki, J; Bogacz, L; Borkowski, J; Bulik, T; Cadoux, F; Christov, A; Curyło, M; della Volpe, D; Dyrda, M; Favre, Y; Frankowski, A; Grudnik, Ł; Grudzińska, M; Heller, M; Idźkowski, B; Jamrozy, M; Janiak, M; Kasperek, J; Lalik, K; Lyard, E; Mach, E; Mandat, D; Marszałek, A; Michałowski, J; Moderski, R; Montaruli, T; Neronov, A; Ostrowski, M; Paśko, P; Pech, M; Porcelli, A; Prandini, E; Rajda, P; Rameez, M; Schioppa, E jr; Schovanek, P; Seweryn, K; Skowron, K; Sliusar, V; Sowiński, M; Stawarz, Ł; Stodulska, M; Stodulski, M; Pujadas, I Troyano; Toscano, S; Walter, R; Wiȩcek, M; Zagdański, A; Ziȩtara, K

    2015-01-01

    A single-mirror small-size (SST-1M) Davies-Cotton telescope with a dish diameter of 4 m has been built by a consortium of Polish and Swiss institutions as a prototype for one of the proposed small-size telescopes for the southern observatory of the Cherenkov Telescope Array (CTA). The design represents a very simple, reliable, and cheap solution. The mechanical structure prototype with its drive system is now being tested at the Institute of Nuclear Physics PAS in Krakow. Here we present the design of the prototype and results of the performance tests of the structure and the drive and control system.

  14. The cern axion solar telescope (CAST)

    Energy Technology Data Exchange (ETDEWEB)

    Aalseth, C. E.; Arik, E.; Autiero, D.; Avignone, F. T.; Barth, K.; Bowyer, S. M.; Brauninger, H.; Brodzinski, R. L.; Carmona, J. M.; Cebrian, S.; Celebi, G.; Cetin, S.; Collar, J. I.; Creswick, R.; Delbart, A.; Delattre, M.; DiLella, L.; De Oliveira, R.; Eleftheriadis, Ch.; Erdutan, N.; Fanourakis, G.; Farach, H. A.; Fiorini, C.; Geralis, Th.; Giomataris, I.; Girard, T. A.; Gninenko, S. N.; Golubev, N. A.; Hasinoff, M.; Hoffmann, D.; Irastorza, I. G.; Jacoby, J.; Jeanneau, F.; Knopf, M. A.; Kovzelev, A. V.; Kotthaus, R.; Krčmar, M.; Krečak, Z.; Lakić, B.; Liolios, A.; Ljubičić, A.; Lutz, G.; Longoni, A.; Luzon, G.; Mailov, A.; Matveev, V. A.; Miley, H. S.; Morales, A.; Morales, J.; Mutterer, M.; Nikolaidis, A.; Nussinov, S.; Ortiz, A.; Pitts, W. K.; Placci, A.; Postoev, V. E.; Raffelt, G. G.; Riege, H.; Sampieto, M.; Sarsa, M.; Savvidis, I.; Stipčević, M.; Thomas, C. W.; Thompson, R. C.; Valco, P.; Villar, J. A.; Villierme, B.; Walckiers, L.; Wilcox, W.; Zachariadou, K.; Zioutas, K.

    2002-07-01

    A decommissioned LHC test magnet is being prepared as the CERN Axion Solar Telescope (CAST) experiment. The magnet has a field of 9.6 Tesla and length of 10 meters. It is being mounted on a platform to track the sun over plus or minus 8 to the sixth power vertically and plus or minus 45 to the sixth power, horizontally.

  15. Axis Offset Estimation of VLBI Telescopes

    Science.gov (United States)

    Krásná, Hana; Nickola, Marisa; Böhm, Johannes

    2014-12-01

    Axis offset models have to be applied for VLBI telescopes with pointing axes which do not intersect. In this work, we estimated the axis offsets for VLBI antennas in a global adjustment of suitable IVS 24-hour sessions (1984.0-2014.0) with the Vienna VLBI Software (VieVS). In particular, we focused on the two radio telescopes of the Hartebeesthoek Radio Astronomy Observatory (HartRAO) in South Africa. For the older 26-m telescope we compared the estimated axis offset values before (6699.2 ± 0.5 mm) and after (6707.3 ± 0.8 mm) the bearing repair in 2010. A comparison with axis offset estimates from other geodetic techniques, such as GNSS or conventional local survey, was made. The estimated axis offset for the newer 15-m telescope (1495.0 ± 3.4 mm) agrees with the estimated value from the GPS survey in 2007. Furthermore, we assessed the influence of differences in the axis offsets on the estimated geodetic parameters, such as station coordinates or Earth Orientation Parameters.

  16. TeraHertz Space Telescope (TST)

    Science.gov (United States)

    Dunn, Marina Madeline; Lesser, David; O'Dougherty, Stephan; Swift, Brandon; Pat, Terrance; Cortez, German; Smith, Steve; Goldsmith, Paul; Walker, Christopher K.

    2017-01-01

    The Terahertz Space Telescope (TST) utilizes breakthrough inflatable technology to create a ~25 m far-infrared observing system at a fraction of the cost of previous space telescopes. As a follow-on to JWST and Herschel, TST will probe the FIR/THz regime with unprecedented sensitivity and angular resolution, answering fundamental questions concerning the origin and destiny of the cosmos. Prior and planned space telescopes have barely scratched the surface of what can be learned in this wavelength region. TST will pick up where JWST and Herschel leave off. At ~30µm TST will have ~10x the sensitivity and ~3x the angular resolution of JWST. At longer wavelengths it will have ~1000x the sensitivity of Herschel and ~7 times the angular resolution. TST can achieve this at low cost through the innovative use of inflatable technology. A recently-completed NIAC Phase II study (Large Balloon Reflector) validated, both analytically and experimentally, the concept of a large inflatable spherical reflector and demonstrated critical telescope functions. In our poster we will introduce the TST concept and compare its performance to past, present, and proposed far-infrared observatories.

  17. Taming the 1.2 m Telescope

    Science.gov (United States)

    Griffin, S.; Edwards, M.; Greenwald, D.; Kono, D.; Liang, D.; Lohnes, K.; Wright, V.; Spillar, E.

    2013-09-01

    Achievable residual jitter on the 1.2 m telescope at MSSS shown in Figure 1 has historically been limited to 10-20 arc-sec. peak in moderate wind conditions due to the combination of the dynamics associated with the twin telescopes on the common declination axis shaft, and the related control system behavior. Figure 1 1.2 m Telescope The lightly damped, low frequency fundamental vibration mode shape of the telescopes rotating out of phase on the common declination axis shaft severely degraded the performance of the prior controllers. This vibration mode is easily excited by external forces such as wind loading and internal torque commands from the mount control system. The relatively poor historic performance was due to a combination of the low error rejection of external disturbances, and the controller exciting the mode. A radical new approach has been implemented that has resulted in a decrease of jitter to less than 1 arcsec under most conditions. The new approach includes minor hardware modifications to provide active damping with accelerometers as feedback sensors. This architecture has allowed a bandwidth increase of almost an order of magnitude and eliminated the large amplitude motions at the mode natural frequency, resulting in much improved pointing and jitter performance. A representative comparison of historical versus new architecture performance is shown in Figure 2 for the declination axis.

  18. The Mathematics of Go to Telescopes

    Science.gov (United States)

    Teets, Donald

    2007-01-01

    This article presents the mathematics involved in finding and tracking celestial objects with an electronically controlled telescope. The essential idea in solving this problem is to choose several different coordinate systems that simplify the various motions of the earth and other celestial objects. These coordinate systems are then related by…

  19. Modeling and control of antennas and telescopes

    CERN Document Server

    Gawronski, Wodek

    2008-01-01

    The book shows, step-by-step, the design, implementation, and testing of the antenna/telescope control system, from the design stage (analytical model) to fine tuning of the RF beam pointing (monopulse and conscan). It includes wide use of Matlab and Simulink..

  20. The telescopic tourist's guide to the Moon

    CERN Document Server

    May, Andrew

    2017-01-01

    Whether you’re interested in visiting Apollo landing sites or the locations of classic sci-fi movies, this is the tourist guide for you! This tourist guide has a twist – it is a guide to a whole different world, which you can visit from the comfort of your backyard with the aid of nothing more sophisticated than an inexpensive telescope. It tells you the best times to view the Moon, the most exciting sights to look out for, and the best equipment to use, allowing you to snap stunning photographs as well as view the sights with your own eyes. Have you ever been inspired by stunning images from the Hubble telescope, or the magic of sci-fi special effects, only to look through a small backyard telescope at the disappointing white dot of a planet or faint blur of a galaxy? Yet the Moon is different. Seen through even a relatively cheap telescope, it springs into life like a real place, with mountains and valleys and rugged craters. With a bit of imagination, you can even picture yourself as a sightseeing visi...