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Sample records for astronomical optical polarimeter

  1. Astronomical optics

    CERN Document Server

    Schroeder, Daniel J

    1988-01-01

    Written by a recognized expert in the field, this clearly presented, well-illustrated book provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today.Key Features* Written by a recognized expert in the field* Provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic i

  2. Optical polarimeter based on Fourier analysis and electronic control

    International Nuclear Information System (INIS)

    In this paper, we show the design and implementation of an optical polarimeter using electronic control and the Fourier analysis. The polarimeter prototype will be used as a main tool for the students of the Universidad Popular del Cesar that belong to the following university programs: Electronics engineering (optoelectronics area), Math and Physics degree and the Master in Physics Sciences, in order to learning the theory and experimental aspects of the state of optical polarization via the Stokes vector measurement. Using the electronic polarimeter proposed in this paper, the students will be able to observe (in an optical bench) and understand the different interactions of the states of optical polarization when the optical waves pass through to the polarizers and retarder waves plates. The electronic polarimeter has a software that captures the optical intensity measurement and evaluates the Stokes vector. (Author)

  3. Electro-Optic Imaging Fourier Transform Spectral Polarimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Boulder Nonlinear Systems, Inc. (BNS) proposes to develop an Electro-Optic Imaging Fourier Transform Spectral Polarimeter (E-O IFTSP). The polarimetric system is...

  4. Astronomical optics and elasticity theory

    CERN Document Server

    Lemaitre, Gerard Rene

    2008-01-01

    Astronomical Optics and Elasticity Theory provides a very thorough and comprehensive account of what is known in this field. After an extensive introduction to optics and elasticity, the book discusses variable curvature and multimode deformable mirrors, as well as, in depth, active optics, its theory and applications. Further, optical design utilizing the Schmidt concept and various types of Schmidt correctors, as well as the elasticity theory of thin plates and shells are elaborated upon. Several active optics methods are developed for obtaining aberration corrected diffraction gratings. Further, a weakly conical shell theory of elasticity is elaborated for the aspherization of grazing incidence telescope mirrors. The very didactic and fairly easy-to-read presentation of the topic will enable PhD students and young researchers to actively participate in challenging astronomical optics and instrumentation projects.

  5. Development and manufacturing of panoramic Stokes polarimeter using the polarization films in the Main Astronomical Observatory of NAS of Ukraine

    Science.gov (United States)

    Vidmachenko, A. P.; Ivanov, Yu. S.; Syniavskyi, I. I.; Sergeev, A. V.

    2015-08-01

    In the Main Astronomical Observatory of NAS of Ukraine is proposed and implemented the concept of the imaging Stokes polarimeter [1-5]. This device allows carrying out measurements of the four Stokes vector components at the same time, in a wide field, and without any restrictions on the relative aperture of the optical system. Its scheme is developed so that only by turning wheel with replaceable elements, photopolarimeter could be transformed into a low resolution spectropolarimeter. The device has four film's polarizers with positional angles 0°, 45°, 90°, 135°. The device uses a system of special deflecting prisms in each channel. These prisms were achromatizing in the spectral range of 420-850 nm [2], the distortion of the polarimeter optical system is less than 0.65%. In manufacturing version of spectropolarimeter provided for the possibility of using working on passing the diffraction grating with a frequency up to 100 lines/mm. Has begun the laboratory testing of instrument. References. 1. Sinyavskii I.I., Ivanov Yu. S., Vidmachenko Anatoliy P., Karpov N.V. Panoramic Stokes-polarimeter // Ecological bulettin of research centers of the Black Sea Economic Cooperation. - 2013. - V. 3, No 4. - P. 123-127. 2. Sinyavskii I. I., Ivanov Yu. S., Vil'machenko A. P. Concept of the construction, of the optical setup of a panoramic Stokes polarimeter for small telescopes // Journal of Optical Technology. - 2013. - V. 80, Issue 9. - P. 545-548. 3. Vidmachenko A. P., Ivanov Yu. S., Morozhenko A. V., Nevodovsky E. P., Syniavskyi I. I., Sosonkin M. G. Spectropolarimeter of ground-based accompanying for the space experiment "Planetary Monitoring" // Kosmichna Nauka i Tekhnologiya. - 2007. - V. 13, No. 1, p. 63 - 70. 4. Yatskiv Ya. S., Vidmachenko A. P., Morozhenko A. V., Sosonkin M. G., Ivanov Yu. S., Syniavskyi I. I. Spectropolarimetric device for overatmospheric investigations of Solar System bodies // Kosmichna Nauka i Tekhnologiya. - 2008. - V. 14, No. 2. - P. 56

  6. Beam Test of a Prototype Phoswich Detector Assembly forthe PoGOLite Astronomical Soft Gamma-ray Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Kanai, Y.; Ueno, M.; Kataoka, J.; Arimoto, M.; Kawai, N.; /Tokyo Inst. Tech.; Yamamoto, K.; Mizuno, T.; Fukazawa, Y.; /Hiroshima U.; Kiss, M.; Ylinen, T.; Bettolo,; Carlson, P.; /Royal Inst. Tech., Stockholm; P.Chen d, B.Craig d, T.Kamae d, G.Madejski d, J.S.T.Ng; Rogers, R.; Tajima, H.; Thurston, T.S.; /SLAC; Saito, Y.; Takahashi, T.; Gunji, S.; /Yamagata U.; Bjornsson, C-I.; Larsson, S.; /Stockholm U. /Ecole Polytechnique /KEK, Tsukuba

    2007-01-17

    We report about the beam test on a prototype of the balloon-based astronomical soft gamma-ray polarimeter, PoGOLite (Polarized Gamma-ray Observer--Light Version) conducted at KEK Photon Factory, a synchrotron radiation facility in Japan. The synchrotron beam was set at 30, 50, and 70 keV and its polarization was monitored by a calibrated polarimeter. The goal of the experiment was to validate the flight design of the polarimeter. PoGOLite is designed to measure polarization by detecting a Compton scattering and the subsequent photo-absorption in an array of 217 well-type phoswich detector cells (PDCs). The test setup included a first flight model PDC and a front-end electronics to select and reconstruct valid Compton scattering events. The experiment has verified that the flight PDC can detect recoil electrons and select valid Compton scattering events down to 30 keV from background. The measure azimuthal modulations (34.4 %, 35.8 % and 37.2 % at 30, 50, and 70 keV, respectively) agreed within 10% (relative) with the predictions by Geant4 implemented with dependence on the initial and final photon polarizations.

  7. Self-referenced, microdegree, optical rotation polarimeter for biomedical applications: an analysis

    Science.gov (United States)

    Weissman, Zeev; Goldberg, Doron

    2016-07-01

    We comprehensively analyze the performance of a type of optical rotation (OR) polarimeter, which has been designed from the outset to fit the special requirements of two major applications: general chiral detection during the separation of optical isomers by high-pressure liquid chromatography systems in the pharmaceutical industry, and monitoring of glucose in the interstitial fluid of diabetics by a fully implanted long-term optical sensor. Both very demanding applications call for an OR polarimeter that can be miniaturized while maintaining high resolution and accuracy in the microdegree range in the face of considerable noise from various sources. These two characteristics-miniature size and immunity to noise-set this polarimeter apart from the traditional OR polarimeters currently in use, which are both bulky and very susceptible to noise. The following detailed analysis demonstrates the advantages of this polarimeter and its potential as an analytic and diagnostic tool.

  8. Planar Integrated Optics and astronomical interferometry

    OpenAIRE

    Kern, Pierre; Berger, Jean-Philippe; Haguenauer, Pierre; Malbet, Fabien; Perraut, Karine

    2001-01-01

    16 pages Integrated optics (IO) is an optical technology that allows to reproduce optical circuits on a planar substrate. Since 1996, we have investigated the potentiality of IO in the framework of astronomical single mode interferometry. We review in this paper the principles of IO, the requirements for interferometry and the corresponding solutions offered by IO, the results of component characterization and the possible fields of application.

  9. An Easily Designed and Constructed Optical Polarimeter for Small Telescopes

    Science.gov (United States)

    Topasna, G. A.; Topasna, D. M.; Popko, G. B.

    2013-09-01

    We have designed, constructed, and tested an optical polarimeter for use with the Virginia Military Institute (VMI) 0.5 m, f/13.5 Cassegrain telescope. Our instrument is based on the common dual-beam design that utilizes a rotatable half-wave plate and Wollaston prism to image starlight onto a CCD detector after it has passed through a broadband filter. The usable field of view is lsim10'' and the operational range of the instrument is 400-700 nm. Measurements of unpolarized stars demonstrate that the instrumental polarization is lsim0.05%. Observations of seven standard stars were in agreement with their accepted values by an order of Δp(%) lsim 0.23 for the degree of polarization and Δθ(°) lsim 0.94 for the position angle.

  10. Polarization Measurement of Spin-Polarized Electrons by Optical Electron Polarimeter

    Institute of Scientific and Technical Information of China (English)

    DING Hai-Bing; PANG Wen-Ning; LIU Yi-Bao; SHANG Ren-Cheng

    2005-01-01

    @@ The polarization of spin-polarized electrons, produced from a new GaAs spin-polarized electron source, is determined by an optical electron polarimeter. The He 3 3p → 23S1 (388.9nm) transition is used for the optical electron polarimetry. The structure and performance of the experimental setup of spin-polarized electron source and optical electron polarimeter are described. The result of polarization of 30.8% averaged spin-up and spindown polarized electrons is obtained and presented.

  11. MHD marking using the MSE polarimeter optics in ILW JET plasmas

    Science.gov (United States)

    Reyes Cortes, S.; Alper, B.; Alves, D.; Baruzzo, M.; Bernardo, J.; Buratti, P.; Coelho, R.; Challis, C.; Chapman, I.; Hawkes, N.; Hender, T. C.; Hobirk, J.; Joffrin, E.

    2016-11-01

    In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

  12. Architecture and performance of astronomical adaptive optics systems

    Science.gov (United States)

    Bloemhof, E.

    2002-01-01

    In recent years the technological advances of adaptive optics have enabled a great deal of innovative science. In this lecture I review the system-level design of modern astronomical AO instruments, and discuss their current capabilities.

  13. Optical layout and mechanical structure of polarimeter-interferometer system for Experimental Advanced Superconducting Tokamak.

    Science.gov (United States)

    Zou, Z Y; Liu, H Q; Jie, Y X; Ding, W X; Brower, D L; Wang, Z X; Shen, J S; An, Z H; Yang, Y; Zeng, L; Wei, X C; Li, G S; Zhu, X; Lan, T

    2014-11-01

    A Far-InfaRed (FIR) three-wave POlarimeter-INTerferometer (POINT) system for measurement current density profile and electron density profile is under development for the EAST tokamak. The FIR beams are transmitted from the laser room to the optical tower adjacent to EAST via ∼20 m overmoded dielectric waveguide and then divided into 5 horizontal chords. The optical arrangement was designed using ZEMAX, which provides information on the beam spot size and energy distribution throughout the optical system. ZEMAX calculations used to optimize the optical layout design are combined with the mechanical design from CATIA, providing a 3D visualization of the entire POINT system.

  14. Optical Alignment of the Chromospheric Lyman-Alpha SpectroPolarimeter using Sophisticated Methods to Minimize Activities under Vacuum

    Science.gov (United States)

    Giono, G.; Katsukawa, Y.; Ishikawa, R.; Narukage, N.; Kano, R.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.; Winebarger, A.; Kobayashi, K.

    2016-01-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding-rocket instrument developed at the National Astronomical Observatory of Japan (NAOJ) as a part of an international collaboration. The in- strument main scientific goal is to achieve polarization measurement of the Lyman-alpha line at 121.56 nm emitted from the solar upper-chromosphere and transition region with an unprecedented 0.1% accuracy. For this purpose, the optics are composed of a Cassegrain telescope coated with a "cold mirror" coating optimized for UV reflection and a dual-channel spectrograph allowing for simultaneous observation of the two orthogonal states of polarization. Although the polarization sensitivity is the most important aspect of the instrument, the spatial and spectral resolutions of the instrument are also crucial to observe the chromospheric features and resolve the Ly- pro les. A precise alignment of the optics is required to ensure the resolutions, but experiments under vacuum conditions are needed since Ly-alpha is absorbed by air, making the alignment experiments difficult. To bypass this issue, we developed methods to align the telescope and the spectrograph separately in visible light. We will explain these methods and present the results for the optical alignment of the CLASP telescope and spectrograph. We will then discuss the combined performances of both parts to derive the expected resolutions of the instrument, and compare them with the flight observations performed on September 3rd 2015.

  15. On the influence of the Illuminati in astronomical adaptive optics

    CERN Document Server

    Morzinski, Katie M

    2012-01-01

    Astronomical adaptive optics (AO) has come into its own. Major O/IR telescopes are achieving diffraction-limited imaging; major facilities are being built with AO as an integral part. To the layperson, it may seem that AO has developed along a serpentine path. However, with a little illumination, the mark of Galileo's heirs becomes apparent in explaining the success of AO.

  16. A Soft X-ray Beam-splitting Multilayer Optic for the NASA GEMS Bragg Reflection Polarimeter

    OpenAIRE

    Allured, Ryan; Fernandez-Perea, Monica; Soufli, Regina; Alameda, Jennifer B.; Pivovaroff, Michael J.; Gullikson, Eric M.; Kaaret, Philip

    2013-01-01

    A soft X-ray, beam-splitting, multilayer optic has been developed for the Bragg Reflection Polarimeter (BRP) on the NASA Gravity and Extreme Magnetism Small Explorer Mission (GEMS). The optic is designed to reflect 0.5 keV X-rays through a 90 degree angle to the BRP detector, and transmit 2-10 keV X-rays to the primary polarimeter. The transmission requirement prevents the use of a thick substrate, so a 2 micron thick polyimide membrane was used. Atomic force microscopy has shown the membrane...

  17. Calibration method for division of focal plane polarimeters in the optical and near-infrared regime

    Science.gov (United States)

    York, Timothy; Gruev, Viktor

    2011-06-01

    Advances in nanofabrication allow for the creation of metallic nanowires acting as linear polarizers in the visible and near infrared regime. The monolithic integration of silicon detectors and pixelated nanowire metallic polarization filters allows for an efficient realization of high resolution polarization imaging sensors. These silicon sensors, known as division of focal plane polarimeters, capture polarization information of the imaged environment from ~400nm to 1050nm wavelength. The performance of the polarization sensor can be degraded by both irregularities in the fabrication of the nanowires and possible misalignment errors during the final deposition of the optical nanowire filters on the surface of the imaging sensor. In addition, electronic offsets due to the readout circuitry, electronic crosstalk, and optical crosstalk will also negatively affect the quality of the polarization information. Partial compensation for many of these post-fabrication errors can be accomplished through the use of a camera calibration routine. This paper will describe one such routine, and show how its application can increase the quality of measurements in both the degree of linear polarization and angle of polarization in the visible spectrum. The imaging array of the division of focal plane polarimeter is segmented into two by two blocks of superpixels. The calibration method chooses one of the four pixels as a reference, and then a gain and offset for each of the remaining three is computed based on this reference. The output is a calibration matrix for each pixel in the image array.

  18. Astronomical optical interferometry, II: Astrophysical results

    Directory of Open Access Journals (Sweden)

    Jankov S.

    2011-01-01

    Full Text Available Optical interferometry is entering a new age with several ground- based long-baseline observatories now making observations of unprecedented spatial resolution. Based on a great leap forward in the quality and quantity of interferometric data, the astrophysical applications are not limited anymore to classical subjects, such as determination of fundamental properties of stars; namely, their effective temperatures, radii, luminosities and masses, but the present rapid development in this field allowed to move to a situation where optical interferometry is a general tool in studies of many astrophysical phenomena. Particularly, the advent of long-baseline interferometers making use of very large pupils has opened the way to faint objects science and first results on extragalactic objects have made it a reality. The first decade of XXI century is also remarkable for aperture synthesis in the visual and near-infrared wavelength regimes, which provided image reconstructions from stellar surfaces to Active Galactic Nuclei. Here I review the numerous astrophysical results obtained up to date, except for binary and multiple stars milliarcsecond astrometry, which should be a subject of an independent detailed review, taking into account its importance and expected results at microarcsecond precision level. To the results obtained with currently available interferometers, I associate the adopted instrumental settings in order to provide a guide for potential users concerning the appropriate instruments which can be used to obtain the desired astrophysical information.

  19. Astronomical Optical Interferometry. I. Methods and Instrumentation

    Directory of Open Access Journals (Sweden)

    Jankov, S.

    2010-12-01

    Full Text Available Previous decade has seen an achievement of large interferometricprojects including 8-10m telescopes and 100m class baselines. Modern computerand control technology has enabled the interferometric combination of lightfrom separate telescopes also in the visible and infrared regimes. Imagingwith milli-arcsecond (mas resolution and astrometry with micro-arcsecond($mu$as precision have thus become reality. Here, I review the methods andinstrumentation corresponding to the current state in the field ofastronomical optical interferometry. First, this review summarizes thedevelopment from the pioneering works of Fizeau and Michelson. Next, thefundamental observables are described, followed by the discussion of the basicdesign principles of modern interferometers. The basic interferometrictechniques such as speckle and aperture masking interferometry, aperture synthesisand nulling interferometry are disscused as well. Using the experience ofpast and existing facilities to illustrate important points, I considerparticularly the new generation of large interferometers that has beenrecently commissioned (most notably, the CHARA, Keck, VLT and LBTInterferometers. Finally, I discuss the longer-term future of opticalinterferometry, including the possibilities of new large-scale ground-based projects and prospects for space interferometry.

  20. A real-time simulation facility for astronomical adaptive optics

    CERN Document Server

    Basden, Alastair

    2014-01-01

    In this paper we introduce the concept of real-time hardware-in-the-loop simulation for astronomical adaptive optics, and present the case for the requirement for such a facility. This real-time simulation, when linked with an adaptive optics real-time control system, provides an essential tool for the validation, verification and integration of the Extremely Large Telescope real-time control systems prior to commissioning at the telescope. We demonstrate that such a facility is crucial for the success of the future extremely large telescopes.

  1. Integration of a thermo-structural analysis with an optical model for PEPSI polarimeter

    Science.gov (United States)

    Di Varano, Igor; Strassmeier, Klaus G.; Ilyin, Ilya; Woche, Manfred; Kaercher, Hans J.

    2011-09-01

    The two spectropolarimeters for PEPSI (Potsdam Echelle Polarimetric and Spectroscopic Instrument) have been de¬signed in order to reconstruct the full Stokes vector measuring linear and circular polarization simultaneously with a re¬solving power of 120,000. The polarimeters will be attached to the Gregorian focus of the so far largest LBT 2x8.4m telescope and will feed together with permanent focus stations the spectrograph via 44m long fibers connection. The spectrograph will be located in a pressure-temperature controlled chamber within the telescope pier. We present hereafter the last results from combined structural and CFD analyses in order to fulfill the optical requirements.

  2. Test facility for astronomical x-ray optics

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Lewis, Robert A.; Bordas, J.

    1990-01-01

    Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earth's atmosphere. These devices require a large collection aperture and the imaging of an x-ray source that is essentially placed at infinity. The ideal testing system for these optical elements has...... to approximate that encountered under working conditions; however, the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area while still retaining...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes, is described. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  3. A Test Facility For Astronomical X-Ray Optics

    DEFF Research Database (Denmark)

    Lewis, R. A.; Bordas, J.; Christensen, Finn Erland

    1989-01-01

    Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earths atmosphere. These devices require a large collection aperture and the imaging of an x-ray source which is essentially placed at infinity. The ideal testing system for these optical elements has...... to approximate that encountered under working conditions, however the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron Radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area whilst still retaining...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes is described below. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  4. Temperature control system for optical elements in astronomical instrumentation

    Science.gov (United States)

    Verducci, Orlando; de Oliveira, Antonio C.; Ribeiro, Flávio F.; Vital de Arruda, Márcio; Gneiding, Clemens D.; Fraga, Luciano

    2014-07-01

    Extremely low temperatures may damage the optical components assembled inside of an astronomical instrument due to the crack in the resin or glue used to attach lenses and mirrors. The environment, very cold and dry, in most of the astronomical observatories contributes to this problem. This paper describes the solution implemented at SOAR for remotely monitoring and controlling temperatures inside of a spectrograph, in order to prevent a possible damage of the optical parts. The system automatically switches on and off some heat dissipation elements, located near the optics, as the measured temperature reaches a trigger value. This value is set to a temperature at which the instrument is not operational to prevent malfunction and only to protect the optics. The software was developed with LabVIEWTM and based on an object-oriented design that offers flexibility and ease of maintenance. As result, the system is able to keep the internal temperature of the instrument above a chosen limit, except perhaps during the response time, due to inertia of the temperature. This inertia can be controlled and even avoided by choosing the correct amount of heat dissipation and location of the thermal elements. A log file records the measured temperature values by the system for operation analysis.

  5. A Soft X-ray Beam-splitting Multilayer Optic for the NASA GEMS Bragg Reflection Polarimeter

    CERN Document Server

    Allured, Ryan; Soufli, Regina; Alameda, Jennifer B; Pivovaroff, Michael J; Gullikson, Eric M; Kaaret, Philip

    2013-01-01

    A soft X-ray, beam-splitting, multilayer optic has been developed for the Bragg Reflection Polarimeter (BRP) on the NASA Gravity and Extreme Magnetism Small Explorer Mission (GEMS). The optic is designed to reflect 0.5 keV X-rays through a 90 degree angle to the BRP detector, and transmit 2-10 keV X-rays to the primary polarimeter. The transmission requirement prevents the use of a thick substrate, so a 2 micron thick polyimide membrane was used. Atomic force microscopy has shown the membrane to possess high spatial frequency roughness less than 0.2 nm rms, permitting adequate X-ray reflectance. A multilayer thin film was especially developed and deposited via magnetron sputtering with reflectance and transmission properties that satisfy the BRP requirements and with near-zero stress. Reflectance and transmission measurements of BRP prototype elements closely match theoretical predictions, both before and after rigorous environmental testing.

  6. Silicon carbide optics for space and ground based astronomical telescopes

    Science.gov (United States)

    Robichaud, Joseph; Sampath, Deepak; Wainer, Chris; Schwartz, Jay; Peton, Craig; Mix, Steve; Heller, Court

    2012-09-01

    Silicon Carbide (SiC) optical materials are being applied widely for both space based and ground based optical telescopes. The material provides a superior weight to stiffness ratio, which is an important metric for the design and fabrication of lightweight space telescopes. The material also has superior thermal properties with a low coefficient of thermal expansion, and a high thermal conductivity. The thermal properties advantages are important for both space based and ground based systems, which typically need to operate under stressing thermal conditions. The paper will review L-3 Integrated Optical Systems - SSG’s (L-3 SSG) work in developing SiC optics and SiC optical systems for astronomical observing systems. L-3 SSG has been fielding SiC optical components and systems for over 25 years. Space systems described will emphasize the recently launched Long Range Reconnaissance Imager (LORRI) developed for JHU-APL and NASA-GSFC. Review of ground based applications of SiC will include supporting L-3 IOS-Brashear’s current contract to provide the 0.65 meter diameter, aspheric SiC secondary mirror for the Advanced Technology Solar Telescope (ATST).

  7. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chuyu [Peking Univ., Beijing (China)

    2012-12-31

    difficulty of diagnostics. For most cases, intercepting measurements are no longer acceptable, and nonintercepting method like synchrotron radiation monitor can not be applied to linear accelerators. The development of accelerator technology asks for simutanous diagnostics innovations, to expand the performance of diagnostic tools to meet the requirements of the next generation accelerators. Diffraction radiation and inverse Compton scattering are two of the most promising techniques, their nonintercepting nature avoids perturbance to the beam and damage to the instrumentation. This thesis is divided into two parts, beam size measurement by optical diffraction radiation and Laser system for Compton polarimeter. Diffraction radiation, produced by the interaction between the electric field of charged particles and the target, is related to transition radiation. Even though the theory of diffraction radiation has been discussed since 1960s, there are only a few experimental studies in recent years. The successful beam size measurement by optical diffraction radiation at CEBAF machine is a milestone: First of all, we have successfully demonstrated diffraction radiation as an effective nonintercepting diagnostics; Secondly, the simple linear relationship between the diffraction radiation image size and the actual beam size improves the reliability of ODR measurements; And, we measured the polarized components of diffraction radiation for the first time and I analyzed the contribution from edge radiation to diffraction radiation.

  8. Synthetic Modeling of Astronomical Closed Loop Adaptive Optics

    CERN Document Server

    Jolissaint, Laurent

    2010-01-01

    We present an analytical model of a single natural guide star astronomical adaptive optics system, in closed loop mode. The model is used to simulate the long exposure system point spread function, using the spatial frequency (or Fourier) approach, and complement an initial open loop model. Applications range from system design, science case analysis and AO data reduction. All the classical phase errors have been included: deformable mirror fitting error, wavefront sensor spatial aliasing, wavefront sensor noise, and the correlated anisoplanatic and servo-lag error. The model includes the deformable mirror spatial transfer function, and the actuator array geometry can be different from the wavefront sensor lenslet array geometry. We also include the dispersion between the sensing and the correction wavelengths. Illustrative examples are given at the end of the paper.

  9. PEM-based polarimeters for industrial applications

    Science.gov (United States)

    Wang, Baoliang

    2010-11-01

    A polarimeter is an optical instrument used in the transmissive mode for determining the polarization state of a light beam, or the polarization-altering properties of a sample, such as diattenuation, retardation and depolarizion.1 (Reflective "polarimeters" are typically called ellipsometers.) Polarimeters can, thus, be broadly categorized as either light-measuring polarimeters or sample-measuring polarimeters. A light-measuring polarimeter is also known as a Stokes polarimeter, which measures the polarization state of a light beam as described by the Stokes parameters. A sample-measuring polarimeter is also known as a Mueller polarimeter, which measures the complete set or a subset of polarization-altering properties of a sample. Polarimeters can also be categorized by whether they measure the complete set of polarization properties. If a Stokes polarimeter measures all four Stokes parameters, it is called a complete Stokes polarimeter; otherwise, an incomplete or a special Stokes polarimeter. Similarly, there are complete and incomplete Mueller polarimeters. Nearly all samplemeasuring polarimeters are incomplete or special polarimeters, particularly for industrial applications. These special polarimeters bear different names. For example, a circular dichroism spectrometer, which measures the differential absorption between left and right circularly polarized light (▵A= AL - AR), is a special polarimeter for measuring the circular diattenuation of a sample; a linear birefringence measurement system is a special polarimeter for measuring the linear retardation of a sample. Polarimeters have a broad range of applications in both academic research and industrial metrology. Polarimeters are applied to chemistry, biology, physics, astronomy, material science and many other scientific areas. Polarimeters are used as metrology tools in the semiconductor, fiber telecommunication, flat panel display, pharmaceutical and many other industries. Different branches of

  10. Multistage spectral polarimeter based on integrated acousto-optical Ti:LiNbO3 TE-TM converters for WDM system monitoring

    Science.gov (United States)

    Noe, Reinhold; Maucher, A.; Ricken, Raimund

    1999-04-01

    A 4-stage spectral polarimeter based on Ti:LiNbO3 acousto- optical TE-TM converters has been realized. It has about 20 dB stopband suppression and can measure polarimetric spectra as well as the time evolution of the state of polarization. A simple optical spectrum analyzer is also proposed.

  11. Geometric optics theory and design of astronomical optical systems using Mathematica

    CERN Document Server

    Romano, Antonio

    2016-01-01

    This text, now in its second edition, presents the mathematical background needed to design many optical combinations that are used in astronomical telescopes and cameras. It uses a novel approach to third-order aberration theory based on Fermat’s principle and the use of particular optical paths (called stigmatic paths) instead of rays, allowing for easier derivation of third-order formulae. Each optical combination analyzed is accompanied by a downloadable Mathematica® notebook that automates its third-order design, eliminating the need for lengthy calculations. The essential aspects of an optical system with an axis of rotational symmetry are introduced first, along with a development of Gaussian optics from Fermat’s principal. A simpler approach to third-order monochromatic aberrations based on both Fermat’s principle and stigmatic paths is then described, followed by a new chapter on fifth-order aberrations and their classification. Several specific optical devices are discussed and analyzed, incl...

  12. UV Written Integrated Optical Beam Combiner for Near Infrared Astronomical Interferometry

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Olivero, Massimo; Jocou, Laurent;

    2006-01-01

    A near infrared integrated optical beam combiner for astronomical interferometry is demonstrated for the first time by direct UV writing. High fringe contrast >95%, low total loss (0.7 dB), low crosstalk and broadband performance is demonstrated.......A near infrared integrated optical beam combiner for astronomical interferometry is demonstrated for the first time by direct UV writing. High fringe contrast >95%, low total loss (0.7 dB), low crosstalk and broadband performance is demonstrated....

  13. Integrated optics for astronomical interferometry; 2, First laboratory white-light interferograms

    CERN Document Server

    Berger, J P; Kern, P; Malbet, M; Schanen-Duport, J P; Reynaud, P; Haguenauer, P; Benech, P

    1999-01-01

    We report first white-light interferograms obtained with an integrated optics beam combiner on a glass plate. These results demonstrate the feasability of single-mode interferometric beam combination with integrated optics technology presented and discussed in paper I. The demonstration is achieved in laboratory with off-the-shelves components coming from micro-sensor applications, not optimized for astronomical use. These two-telescope beam combiners made by ion exchange technique on glass substrate provide laboratory white-light interferograms simultaneously with photometric calibration. A dedicated interferometric workbench using optical fibers is set up to characterize these devices. Despite the rather low match of the component parameters to astronomical constraints, we obtain stable contrasts higher than 93% with a 1.54-\\micron laser source and up to 78% with a white-light source in the astronomical H band. Global throughput of 27% for a potassium ion exchange beam combiner and of 43% for a silver one a...

  14. Optical linear polarization of 74 white dwarfs with the RoboPol polarimeter

    CERN Document Server

    Żejmo, M; Krzeszowski, K; Reig, P; Blinov, D

    2016-01-01

    We present the first linear polarimetric survey of white dwarfs (WDs). Our sample consists of WDs of DA and DC spectral types in the SDSS r magnitude range from 13 to 17. We performed polarimetric observations with the RoboPol polarimeter attached to the 1.3-m telescope at the Skinakas Observatory. We have 74 WDs in our sample, of which almost all are low polarized WDs with polarization degree (PD) smaller than 1%, while only 2 have PD higher than 1%. There is an evidence that on average the isolated WDs of DC type have higher PD (with median PD of 0.78%) than the isolated DA type WDs (with median PD of 0.36%). On the other hand, the median PD of isolated DA type WDs is almost the same, i.e. 0.36% as the median PD of DA type white dwarfs in binary systems with red dwarfs (dM type), i.e. 0.33%. This shows, as expected, that there is no contribution to the PD from the companion if the WD companion is the red dwarf, which is the most common situation for WDs binary systems. We do not find differences in the pola...

  15. POET: POlarimeters for Energetic Transients

    CERN Document Server

    Hill, J E; Bloser, P; Legere, J; Macri, J; Ryan, J; Barthelmy, S; Angelini, L; Sakamoto, T; Black, J K; Hartmann, D H; Kaaret, Philip; Zhang, B; Ioka, K; Nakamura, T; Toma, K; Yamazaki, R; Wu, X

    2008-01-01

    POET (Polarimeters for Energetic Transients) is a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment -- GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The POET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. POET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  16. Simulation of Astronomical Images from Optical Survey Telescopes using a Comprehensive Photon Monte Carlo Approach

    CERN Document Server

    Peterson, J R; Kahn, S M; Rasmussen, A P; Peng, E; Ahmad, Z; Bankert, J; Chang, C; Claver, C; Gilmore, D K; Grace, E; Hannel, M; Hodge, M; Lorenz, S; Lupu, A; Meert, A; Nagarajan, S; Todd, N; Winans, A; Young, M

    2015-01-01

    We present a comprehensive methodology for the simulation of astronomical images from optical survey telescopes. We use a photon Monte Carlo approach to construct images by sampling photons from models of astronomical source populations, and then simulating those photons through the system as they interact with the atmosphere, telescope, and camera. We demonstrate that all physical effects for optical light that determine the shapes, locations, and brightnesses of individual stars and galaxies can be accurately represented in this formalism. By using large scale grid computing, modern processors, and an efficient implementation that can produce 400,000 photons/second, we demonstrate that even very large optical surveys can be now be simulated. We demonstrate that we are able to: 1) construct kilometer scale phase screens necessary for wide-field telescopes, 2) reproduce atmospheric point-spread-function moments using a fast novel hybrid geometric/Fourier technique for non-diffraction limited telescopes, 3) ac...

  17. Analysis of astronomical data from optical superconducting tunnel junctions

    CERN Document Server

    De Bruijne, J H J; Perryman, M A C; Favata, F; Peacock, A; Bruijne, Jos H.J. de; Reynolds, Alastair P; Perryman, Michael .A.C.; Favata, Fabio; Peacock, Anthony

    2001-01-01

    Currently operating optical superconducting tunnel junction (STJ) detectors, developed in ESA, can simultaneously measure the wavelength (delta lambda = 50 nm at 500 nm) and arrival time (to within ~5 micros) of individual photons in the range 310-720 nm with an efficiency of ~70%, and with count rates of order 5,000 photons per second per junction. A number of STJ junctions placed in an array format generates four-dimensional data: photon arrival time, energy, and array element (X,Y). Such STJ cameras are ideally suited for, e.g., high time- resolution spectrally-resolved monitoring of variable sources or low-resolution spectroscopy of faint extragalactic objects. The reduction of STJ data involves detector efficiency correction, atmo- spheric extinction correction, sky background subtraction, and, unlike that of data from CCD-based systems, a more complex energy calibration, barycentric arrival time correction, energy range selection, and time binning; these steps are, in many respects, analogous to procedu...

  18. New Methods of Optical Modeling for Astronomical Instrumentation

    Science.gov (United States)

    Sutin, B.

    1996-05-01

    A new raytracing program written by the author is being used to model the Keck II telescope and two new instruments currently being built at UCO/Lick Observatory, DEIMOS and ESI. Optical systems are written as programs in a block-structured programming language which includes arbitrary mathematical expressions. Full three-dimensional models of the telescope and instruments are raytraced, and a complete description of the final system can be written as an AutoCAD file for mechanical engineering purposes. Detailed spectral format, distortion, image diameters, and beam "footprints" at any surface are easily displayed. Light losses from surface reflections and internal absorption in refractive elements and vignetting are calculated. Examples of each of these uses are given for either the DEIMOS or ESI instruments.

  19. Astronomical phenomena: events with high impact factor in teaching optics and photonics

    Science.gov (United States)

    Curticapean, Dan

    2014-07-01

    Astronomical phenomena fascinate people from the very beginning of mankind up to today. They have a enthusiastic effect, especially on young people. Among the most amazing and well-known phenomena are the sun and moon eclipses. The impact factor of such events is very high, as they are being covered by mass media reports and the Internet, which provides encyclopedic content and discussion in social networks. The principal optics and photonics topics that can be included in such lessons originate from geometrical optics and the basic phenomena of reflection, refraction and total internal reflection. Lenses and lens systems up to astronomical instruments also have a good opportunity to be presented. The scientific content can be focused on geometrical optics but also diffractive and quantum optics can be incorporated successfully. The author will present how live streams of the moon eclipses can be used to captivate the interest of young listeners for optics and photonics. The gathered experience of the last two moon eclipses visible from Germany (on Dec, 21 2010 and Jun, 15 2011) will be considered. In an interactive broadcast we reached visitors from more than 135 countries.

  20. SIMULATION OF ASTRONOMICAL IMAGES FROM OPTICAL SURVEY TELESCOPES USING A COMPREHENSIVE PHOTON MONTE CARLO APPROACH

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, J. R.; Peng, E.; Ahmad, Z.; Bankert, J.; Grace, E.; Hannel, M.; Hodge, M.; Lorenz, S.; Lupu, A.; Meert, A.; Nagarajan, S.; Todd, N.; Winans, A.; Young, M. [Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907 (United States); Jernigan, J. G. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Kahn, S. M.; Rasmussen, A. P.; Chang, C.; Gilmore, D. K. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Claver, C., E-mail: peters11@purdue.edu [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)

    2015-05-15

    We present a comprehensive methodology for the simulation of astronomical images from optical survey telescopes. We use a photon Monte Carlo approach to construct images by sampling photons from models of astronomical source populations, and then simulating those photons through the system as they interact with the atmosphere, telescope, and camera. We demonstrate that all physical effects for optical light that determine the shapes, locations, and brightnesses of individual stars and galaxies can be accurately represented in this formalism. By using large scale grid computing, modern processors, and an efficient implementation that can produce 400,000 photons s{sup −1}, we demonstrate that even very large optical surveys can be now be simulated. We demonstrate that we are able to (1) construct kilometer scale phase screens necessary for wide-field telescopes, (2) reproduce atmospheric point-spread function moments using a fast novel hybrid geometric/Fourier technique for non-diffraction limited telescopes, (3) accurately reproduce the expected spot diagrams for complex aspheric optical designs, and (4) recover system effective area predicted from analytic photometry integrals. This new code, the Photon Simulator (PhoSim), is publicly available. We have implemented the Large Synoptic Survey Telescope design, and it can be extended to other telescopes. We expect that because of the comprehensive physics implemented in PhoSim, it will be used by the community to plan future observations, interpret detailed existing observations, and quantify systematics related to various astronomical measurements. Future development and validation by comparisons with real data will continue to improve the fidelity and usability of the code.

  1. Optical Characterization of the BICEP3 CMB Polarimeter at the South Pole

    CERN Document Server

    Karkare, K S; Ahmed, Z; Alexander, K D; Amiri, M; Barkats, D; Benton, S J; Bischoff, C A; Bock, J J; Boenish, H; Bowens-Rubin, R; Buder, I; Bullock, E; Buza, V; Connors, J; Filippini, J P; Fliescher, S T; Grayson, J A; Halpern, M; Harrison, S A; Hilton, G C; Hristov, V V; Hui, H; Irwin, K D; Kang, J H; Karpel, E; Kefeli, S; Kernasovskiy, S A; Kovac, J M; Kuo, C L; Leitch, E M; Lueker, M; Megerian, K G; Monticue, V; Namikawa, T; Netterfield, C B; Nguyen, H T; O'Brient, R; Ogburn, R W; Pryke, C; Reintsema, C D; Richter, S; Germaine, M T St; Schwarz, R; Sheehy, C D; Staniszewski, Z K; Steinbach, B; Teply, G P; Thompson, K L; Tolan, J E; Tucker, C; Turner, A D; Vieregg, A G; Wandui, A; Weber, A; Willmert, J; Wong, C L; Wu, W L K; Yoon, K W

    2016-01-01

    BICEP3 is a small-aperture refracting cosmic microwave background (CMB) telescope designed to make sensitive polarization maps in pursuit of a potential B-mode signal from inflationary gravitational waves. It is the latest in the BICEP/Keck Array series of CMB experiments at the South Pole, which has provided the most stringent constraints on inflation to date. For the 2016 observing season, BICEP3 was outfitted with a full suite of 2400 optically coupled detectors operating at 95 GHz. In these proceedings we report on the far field beam performance using calibration data taken during the 2015-2016 summer deployment season in situ with a thermal chopped source. We generate high-fidelity per-detector beam maps, show the array-averaged beam profile, and characterize the differential beam response between co-located, orthogonally polarized detectors which contributes to the leading instrumental systematic in pair differencing experiments. We find that the levels of differential pointing, beamwidth, and elliptici...

  2. Novel optical designs for consumer astronomical telescopes and their application to professional imaging

    Science.gov (United States)

    Wise, Peter; Hodgson, Alan

    2006-06-01

    Since the launch of the Hubble Space Telescope there has been widespread popular interest in astronomy. A further series of events, most notably the recent Deep Impact mission and Mars oppositions have served to fuel further interest. As a result more and more amateurs are coming into astronomy as a practical hobby. At the same time more sophisticated optical equipment is becoming available as the price to performance ratio become more favourable. As a result larger and better optical telescopes are now in use by amateurs. We also have the explosive growth in digital imaging technologies. In addition to displacing photographic film as the preferred image capture modality it has made the capture of high quality astronomical imagery more accessible to a wider segment of the astronomy community. However, this customer requirement has also had an impact on telescope design. There has become a greater imperative for wide flat image fields in these telescopes to take advantage of the ongoing advances in CCD imaging technology. As a result of these market drivers designers of consumer astronomical telescopes are now producing state of the art designs that result in wide, flat fields with optimal spatial and chromatic aberrations. Whilst some of these designs are not scalable to the larger apertures required for professional ground and airborne telescope use there are some that are eminently suited to make this transition.

  3. Daytime Use of Astronomical Telescopes for Deep-Space Optical Links

    Science.gov (United States)

    Roberts, W. Thomas; Ortiz, Gerard G.; Boyd, Tim A.

    2006-01-01

    Tests at the 200-inch Hale Telescope on Palomar Mountain have demonstrated this telescope's ability to withstand considerable thermal stress, and subsequently produce remarkably unaffected results. During the day of June 29,2005, the Hale telescope dome was left open, and the telescope was exposed to outside air and direct sunlight for 8 hours. During this time, portions of the telescope structure in the telescope's optical path experienced temperature elevations of 30 C, while the primary mirror experienced unprecedented heating of over 3 C. The telescope's measured blind pointing accuracy after this exposure was not noticeably degraded from the measurements taken before exposure. More remarkably, the telescope consistently produced stellar images which were significantly better after exposure of the telescope (1.2 arcsec) than before (1.6 arcsec), even though the conditions of observation were similar. This data is the first step in co-opting astronomical telescopes for daytime use as astronomical receivers, and supports the contention that deleterious effects from daytime exposure of the telescope can be held to an acceptable level for interleaved communications and astronomy.

  4. Ultraviolet spectrometer and polarimeter for the Solar Maximum Mission.

    Science.gov (United States)

    Miller, M S; Caruso, A J; Woodgate, B E; Sterk, A A

    1981-11-01

    The detailed optical design of the Solar Maximum Mission-Ultraviolet Spectrometer and Polarimeter is discussed in conjunction with the scientific objectives that led to the design. The instrument consists of a 1.8-m effective focal length aplanatic Gregorian telescope followed by a 1-m Ebert spectrometer. The design of the Stokes polarimeter is also discussed. PMID:20372263

  5. Development of thermally formed glass optics for astronomical hard X-ray telescopes

    DEFF Research Database (Denmark)

    Craig, W.W.; Hailey, C.J.; Jimenez-Garate, M.;

    2000-01-01

    . The recent development of depth-graded multilayer coatings has made the design of telescopes for this bandpass practical, however the ability to manufacture inexpensive substrates with appropriate surface quality and figure to achieve sub-arcminute performance has remained an elusive goal. In this paper, we......The next major observational advance in hard X-ray/soft gamma-ray astrophysics will come with the implementation of telescopes capable of focusing 10-200 keV radiation. Focusing allows high signal-to-noise imaging and spectroscopic observations of many sources in this band for the first time...... report on new, thermally-formed glass micro-sheet optics capable of meeting the requirements of the next-generation of astronomical hard X-ray telescopes....

  6. LWIR Snapshot Imaging Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Robert E Sampson

    2009-04-01

    This report describes the results of a phase 1 STTR to design a longwave infrared imaging polarimeter. The system design, expected performance and components needed to construct the imaging polarimeter are described. Expected performance is modeled and sytem specifications are presented.

  7. The AGS CNI polarimeter

    International Nuclear Information System (INIS)

    A new polarimeter is being installed in the Brookhaven AGS, based on the successful proton-carbon polarimeters in RHIC. The polarimeter will measure the left-right asymmetry for proton-carbon elastic scattering in the Coulomb-nuclear interference (CNI) region, for vertically polarized protons in the AGS. The polarimeter offers a much higher figure of merit than the existing AGS polarimeter which is based on larger angle proton-proton elastic scattering. We expect to measure the polarization in the AGS with a single or a few acceleration cycles. We also plan to measure the polarization in 2 ms bins during the AGS acceleration ramp. Multiple ramps will be necessary, probably over 30 minutes to an hour

  8. Astronomical optical frequency comb generation and test in a fiber-fed MUSE spectrograph

    Science.gov (United States)

    Chavez Boggio, J. M.; Fremberg, T.; Moralejo, B.; Rutowska, M.; Hernandez, E.; Zajnulina, M.; Kelz, A.; Bodenmüller, D.; Sandin, C.; Wysmolek, M.; Sayinc, H.; Neumann, J.; Haynes, R.; Roth, M. M.

    2014-07-01

    We here report on recent progress on astronomical optical frequency comb generation at innoFSPEC-Potsdam and present preliminary test results using the fiber-fed Multi Unit Spectroscopic Explorer (MUSE) spectrograph. The frequency comb is generated by propagating two free-running lasers at 1554.3 and 1558.9 nm through two dispersionoptimized nonlinear fibers. The generated comb is centered at 1590 nm and comprises more than one hundred lines with an optical-signal-to-noise ratio larger than 30 dB. A nonlinear crystal is used to frequency double the whole comb spectrum, which is efficiently converted into the 800 nm spectral band. We evaluate first the wavelength stability using an optical spectrum analyzer with 0.02 nm resolution and wavelength grid of 0.01 nm. After confirming the stability within 0.01 nm, we compare the spectra of the astro-comb and the Ne and Hg calibration lamps: the astro-comb exhibits a much larger number of lines than lamp calibration sources. A series of preliminary tests using a fiber-fed MUSE spectrograph are subsequently carried out with the main goal of assessing the equidistancy of the comb lines. Using a P3d data reduction software we determine the centroid and the width of each comb line (for each of the 400 fibers feeding the spectrograph): equidistancy is confirmed with an absolute accuracy of 0.4 pm.

  9. Laser-based capillary polarimeter.

    Science.gov (United States)

    Swinney, K; Hankins, J; Bornhop, D J

    1999-01-01

    A laser-based capillary polarimeter has been configured to allow for the detection of optically active molecules in capillary tubes with a characteristic inner diameter of 250 microm and a 39-nL (10(-9)) sample volume. The simple optical configuration consists of a HeNe laser, polarizing optic, fused-silica capillary, and charge-coupled device (CCD) camera in communication with a laser beam analyzer. The capillary scale polarimeter is based on the interaction between a polarized laser beam and a capillary tube, which results in a 360 degree fan of scattered light. This array of scattered light contains a set of interference fringe, which respond in a reproducible manner to changes in solute optical activity. The polarimetric utility of the instrument will be demonstrated by the analysis of two optically active solutes, R-mandelic acid and D-glucose, in addition to the nonoptically active control, glycerol. The polarimetric response of the system is quantifiable with detection limits facilitating 1.7 x 10(-3) M or 68 x 10(-12) nmol (7 psi 10(-9) g) sensitivity. PMID:11315158

  10. About study of radiation flux carried out on the stand, which is designed for testing of space ultraviolet polarimeter

    Science.gov (United States)

    Nevodovskiy, P. V.; Vidmachenko, A. P.; Geraimchuk, M. D.; Ivahiv, O. V.

    2016-08-01

    In the Main Astronomical Observatory of NAS of Ukraine, National Technical University of Ukraine "KPI" and National University "Lviv Polytechnic" over the many years has accumulated considerable experience of work on the design and development of polarimeters, and created a working model of compact an onboard ultraviolet polarimeter (UFP) [1-6]. For debugging, research and testing as the entire layout of UFP and its individual parts we have created a special stand with complex equipment that allows carrying the following works. The structural construction of the stand allows obtaining characteristics as a whole unit, and its individual parts; obtaining spectral dependences and counting characteristics signal of the light radiation, and of dark signal; carry out the polarization measurements and more. For this stand developed a number of special techniques to study various parameters of all UFP appliance and its individual parts. Thus, for control - characteristics and calibration of elements of photo-detector system of electro-optical equipment, must use the reference emitters. But they are complicated and expensive. Therefore for simplified calibration and configuration of optical devices, it is expedient to use cheap and small in size, but specially selected LEDs. For this, developed for testing of UFP stand, has been modernized. Thus, the selection was carried out, and then carefully studied the sources of radiation, that will be used for calibration of polarimeters. More information on this work expounded in the report. References. 1. P. Nevodovskyi, O. Morozhenko, A. Vidmachenko, O. Ivakhiv, M. Geraimchuk, O. Zbrutskyi. Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation // Proceedings of 8th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS'2015). 24-26 September 2015, Proceedings. Warsaw, Poland. Vol.81, p. 28-32. 2. Nevodovsksiy P. V., Morozhenko A. V

  11. The Submillimeter Array Polarimeter

    OpenAIRE

    Marrone, Daniel P.; Rao, Ramprasad

    2008-01-01

    We describe the Submillimeter Array (SMA) Polarimeter, a polarization converter and feed multiplexer installed on the SMA. The polarimeter uses narrow-band quarter-wave plates to generate circular polarization sensitivity from the linearly-polarized SMA feeds. The wave plates are mounted in rotation stages under computer control so that the polarization handedness of each antenna is rapidly selectable. Positioning of the wave plates is found to be highly repeatable, better than 0.2 degrees. A...

  12. Affordable and Lightweight High-Resolution X-ray Optics for Astronomical Missions

    Science.gov (United States)

    Zhang, W. W.; Biskach, M. P.; Bly, V. T.; Carter, J. M.; Chan, K. W.; Gaskin, J. A.; Hong, M.; Hohl, B. R.; Jones, W. D.; Kolodziejczak, J. J.

    2014-01-01

    Future x-ray astronomical missions require x-ray mirror assemblies that provide both high angular resolution and large photon collecting area. In addition, as x-ray astronomy undertakes more sensitive sky surveys, a large field of view is becoming increasingly important as well. Since implementation of these requirements must be carried out in broad political and economical contexts, any technology that meets these performance requirements must also be financially affordable and can be implemented on a reasonable schedule. In this paper we report on progress of an x-ray optics development program that has been designed to address all of these requirements. The program adopts the segmented optical design, thereby is capable of making both small and large mirror assemblies for missions of any size. This program has five technical elements: (1) fabrication of mirror substrates, (2) coating, (3) alignment, (4) bonding, and (5) mirror module systems engineering and testing. In the past year we have made progress in each of these five areas, advancing the angular resolution of mirror modules from 10.8 arc-seconds half-power diameter reported (HPD) a year ago to 8.3 arc-seconds now. These mirror modules have been subjected to and passed all environmental tests, including vibration, acoustic, and thermal vacuum. As such this technology is ready for implementing a mission that requires a 10-arc-second mirror assembly. Further development in the next two years would make it ready for a mission requiring a 5-arc-second mirror assembly. We expect that, by the end of this decade, this technology would enable the x-ray astrophysical community to compete effectively for a major x-ray mission in the 2020s that would require one or more 1-arc-second mirror assemblies for imaging, spectroscopic, timing, and survey studies.

  13. A subwavelength Stokes polarimeter on a silicon chip

    Science.gov (United States)

    Espinosa Soria, A.; Rodríguez-Fortuño, Francisco J.; Griol, Amadeu; Martínez, Alejandro

    2016-04-01

    Measuring the state of polarization (SoP) of light beams is of paramount importance in many scientific and technological disciplines, including chemistry, biosensing, astronomy and optical communications. Commercial polarimeters are built by using bulky and expensive optical elements, including half-wave plates or grid polarizers, with little prospect for miniaturization. Inspired by the concept of spin-orbit coupling, here we introduce a nanophotonic polarimeter that measures the full SoP - Stokes parameters - of a light beam over an ultrabroad wavelength range. The active region of the device, formed by a metallic nanoantenna on top of a silicon waveguide crossing, is less than a square wavelength, one order of magnitude smaller than polarimeters based on metasurfaces and many orders of magnitude smaller than commercial devices. Our approach is universal and therefore applicable to any wavelength regime and technological platform, opening a new route for miniaturized polarimeters.

  14. A convergent blind deconvolution method for post-adaptive-optics astronomical imaging

    International Nuclear Information System (INIS)

    In this paper, we propose a blind deconvolution method which applies to data perturbed by Poisson noise. The objective function is a generalized Kullback–Leibler (KL) divergence, depending on both the unknown object and unknown point spread function (PSF), without the addition of regularization terms; constrained minimization, with suitable convex constraints on both unknowns, is considered. The problem is non-convex and we propose to solve it by means of an inexact alternating minimization method, whose global convergence to stationary points of the objective function has been recently proved in a general setting. The method is iterative and each iteration, also called outer iteration, consists of alternating an update of the object and the PSF by means of a fixed number of iterations, also called inner iterations, of the scaled gradient projection (SGP) method. Therefore, the method is similar to other proposed methods based on the Richardson–Lucy (RL) algorithm, with SGP replacing RL. The use of SGP has two advantages: first, it allows one to prove global convergence of the blind method; secondly, it allows the introduction of different constraints on the object and the PSF. The specific constraint on the PSF, besides non-negativity and normalization, is an upper bound derived from the so-called Strehl ratio (SR), which is the ratio between the peak value of an aberrated versus a perfect wavefront. Therefore, a typical application, but not a unique one, is to the imaging of modern telescopes equipped with adaptive optics systems for the partial correction of the aberrations due to atmospheric turbulence. In the paper, we describe in detail the algorithm and we recall the results leading to its convergence. Moreover, we illustrate its effectiveness by means of numerical experiments whose results indicate that the method, pushed to convergence, is very promising in the reconstruction of non-dense stellar clusters. The case of more complex astronomical targets

  15. dst: Polarimeter data destriper

    Science.gov (United States)

    Zonca, Andrea

    2015-01-01

    Dst is a fully parallel Python destriping code for polarimeter data; destriping is a well-established technique for removing low-frequency correlated noise from Cosmic Microwave Background (CMB) survey data. The software destripes correctly formatted HDF5 datasets and outputs hitmaps, binned maps, destriped maps and baseline arrays.

  16. A Brief History of Astronomical Brightness Determination Methods at Optical Wavelengths

    CERN Document Server

    Krisciunas, K

    2001-01-01

    In this brief article I review the history of astronomical photometry, touching on observations made by the ancient Chinese, Hipparchus and Ptolemy, the development of the concept (and definition) of magnitude, the endeavors of Argelander and Zoellner, work at Harvard at the end of the 19th century, and the development of photography, photomultipliers, and CCD's and their application to astronomy.

  17. Optimization of system parameters for a complete multispectral polarimeter

    International Nuclear Information System (INIS)

    We optimize a general class of complete multispectral polarimeters with respect to signal-to-noise ratio, stability against alignment errors, and the minimization of errors regarding a given set of polarization states. The class of polarimeters that are dealt with consists of at least four polarization optics each with a multispectral detector. A polarization optic is made of an azimuthal oriented wave plate and a polarizing filter. A general, but not unique, analytic solution that minimizes signal-to-noise ratio is introduced for a polarimeter that incorporates four simultaneous measurements with four independent optics. The optics consist of four sufficient wave plates, where at least one is a quarter-wave plate. The solution is stable with respect to the retardance of the quarter-wave plate; therefore, it can be applied to real-world cases where the retardance deviates from λ/4. The solution is a set of seven rotational parameters that depends on the given retardances of the wave plates. It can be applied to a broad range of real world cases. A numerical method for the optimization of arbitrary polarimeters of the type discussed is also presented and applied for two cases. First, the class of polarimeters that were analytically dealt with are further optimized with respect to stability and error performance with respect to linear polarized states. Then a multispectral case for a polarimeter that consists of four optics with real achromatic wave plates is presented. This case was used as the theoretical background for the development of the Airborne Multi-Spectral Sunphoto- and Polarimeter (AMSSP), which is an instrument for the German research aircraft HALO.

  18. The new 2meter RCC Telescope in the Northern CAucasus (3100m) for Modern Astronomical Research

    Science.gov (United States)

    Tarady, V.; Yatskiv, Ya.

    A new 2 meter Ritchey-Chretien-Coude telescope in the Northern Caucasus is expected to be ready for astronomical research in late 1995. The telescope is located on the Terskol peak (near Elbrus) with the altitude of 3100 meter. The low atmospheric water vapour content and the high air transparency in the ultraviolet region allow us to infer that the Terskol peak is one of the best sites in Europe for astronomical ground observation. The mean seeing is about 1 arcsec at the Terskol peak. The main parameters of the optical system are as follows: * equivalent focal length is 16000 mm for the Ritchey-Chretien system and 72000 mm for the Coude system; * diameter of the field free from vignetting is 108' for the Ritchey-Chretien system and 5' for another one; *spot concentration is 80% inside the 0.5" circle. The new telescope will be used in investigating the fundamental problems of the star brightness variability, physics of stars and galaxies, studying the planet and satellite atmosphere dynamics. The precise astrometrical problems can also be solved with this telescope. The telescope will be equiped with the following detectors: -CCD Echelle spectrograph in the Coude focus; - astronomical infrared Fourie spectrometre; -digital panoramic polarimeter; -panoramic spectrophotometer with Fabry-Perot interferometer. This project is realized by the joint efforts of the Main Astronomical Observatory in Kiev (Ukrainian Academy of Sciences) and the International Centre for Astronomical and Medical-Ecological Investigations. Proposals for Scientific observation at the Terskol Observatory are encouraged.

  19. Better Alternative to "Astronomical Silicate": Laboratory-Based Optical Functions of Chondritic/Solar Abundance Glass With Application to HD161796

    CERN Document Server

    Speck, A K; Hofmeister, A M

    2015-01-01

    "Astronomical" or "circumstellar" silicate optical functions (real and imaginary indices of refraction n and k have been previously derived from compositionally and structurally disparate samples; past values were compiled from different sources in the literature, and are essentially kluges of observational, laboratory, and extrapolated or interpolated values. These synthetic optical functions were created because astronomers lack the quantitative data on amorphous silicates at all wavelengths needed for radiative transfer modeling. This paper provides optical functions that (1) are created with a consistent methodology, (2) use the same sample across all wavelengths, and (3) minimize interpolation and extrapolation wherever possible. We present electronic data tables of optical functions derived from mid-ultraviolet to far-infrared laboratory transmission spectra for two materials: iron-free glass with chondritic/solar atmospheric abundances, and metallic iron. We compare these optical functions to other pop...

  20. A Far Infrared Polarimeter

    CERN Document Server

    Catalano, A

    2004-01-01

    We describe an experiment to measure calibration sources, the polarization of Cosmic Microwave Background Radiation (CMBR) and the polarization induced on the CMBR from S-Z effects, using a polarimeter, MITOPol, that will be employed at the MITO telescope. Two modulation methods are presented and compared: an amplitude modulation with a Fresnel double rhomb and a phase modulation with a modified Martin-Puplett interferometer. A first light is presented from the campaign (summer 2003) that has permitted to estimate the instrument spurious polarization using the second modulation method.

  1. On testing of the photometer-polarimeter UVP layout using a telescope on Earth's surface

    Science.gov (United States)

    Nevodovskyi, P. V.; Vidmachenko, A. P.; Morozhenko, O. V.; Zbrutskyi, O.; Ivakhiv, O. V.

    2016-08-01

    One of the causes of climate change (changing of concentration of stratospheric ozone) - is variations due to aerosol optical thickness in the upper layers of Earth's atmosphere. To solve the problem is necessary to make a space experiment to receive polarization observational data. Their analysis will: determine the value of the real part of the refractive index, the size of the stratospheric aerosol, optical thickness of the stratospheric aerosol layer, investigate aerosol's layer horizontal structure and its changes over time. Main Astronomical Observatory of NAS of Ukraine jointly with the National Technical University of Ukraine "KPI" and National University "Lviv Polytechnic" for a long time working on the design of polarimeter to study the stratospheric layer of the Earth from board of artificial satellites. During this time accumulated a great experience in such work, and created a layout of compact board ultraviolet polarimeter UFP [1-4]. For testing of ground variant of layout of UFP, it is installed on the telescope AZT-2 of the Main Astronomical Observatory NAS of Ukraine (Kyiv). Using it we plan to investigate the possibility of determining the degree of polarization of the twilight glow of Earth's atmosphere, and implementation of this technique in the development of space experiment on investigation of the stratospheric aerosol from space. For this purpose we develop a special set of equipment that will adapt the layout for working of UFP with telescope AZT-2, and carry out the above mentioned work (see. in [5-7]). References. 1. P. Nevodovskyi, O. Morozhenko, A. Vidmachenko, O. Ivakhiv, M. Geraimchuk, O. Zbrutskyi. Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation // Proceedings of 8th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS'2015). 24-26 September 2015, Proceedings. Warsaw, Poland. Vol.81, p. 28-32. 2. Nevodovsksiy P. V., Morozhenko A

  2. Investigation of Power8 processors for astronomical adaptive optics real-time control

    CERN Document Server

    Basden, Alastair

    2015-01-01

    The forthcoming Extremely Large Telescopes all require adaptive optics systems for their successful operation. The real-time control for these systems becomes computationally challenging, in part limited by the memory bandwidths required for wavefront reconstruction. We investigate new POWER8 processor technologies applied to the problem of real-time control for adaptive optics. These processors have a large memory bandwidth, and we show that they are suitable for operation of first-light ELT instrumentation, and propose some potential real-time control system designs. A CPU-based real-time control system significantly reduces complexity, improves maintainability, and leads to increased longevity for the real-time control system.

  3. Using 50-mm electrostatic membrane deformable mirror in astronomical adaptive optics

    NARCIS (Netherlands)

    Tokovinin, A.; Thomas, S.; Vdovin, G.

    2004-01-01

    Membrane micro-machined deformable mirrors (MMDM) feature low cost, low power consumption, small size and absence of hysteresis. Interested in using such a device for the adaptive optics system at the SOAR 4.1-m telescope, we evaluated the performance of a 79-channel 50-mm (pupil size 35mm) MMDM fro

  4. Ly-alpha polarimeter design for CLASP rocket experiment

    CERN Document Server

    Watanabe, H; Kubo, M; Ishikawa, R; Bando, T; Kano, R; Tsuneta, S; Kobayashi, K; Ichimoto, K; Trujillo-Bueno, J

    2014-01-01

    A sounding-rocket program called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is proposed to be launched in the summer of 2014. CLASP will observe the solar chromosphere in Ly-alpha (121.567 nm), aiming to detect the linear polarization signal produced by scattering processes and the Hanle effect for the first time. The polarimeter of CLASP consists of a rotating half-waveplate, a beam splitter, and a polarization analyzer. Magnesium Fluoride (MgF2) is used for these optical components, because MgF2 exhibits birefringent property and high transparency at ultraviolet wavelength.

  5. Analyzing the Data from X-ray Polarimeters with Stokes Parameters

    CERN Document Server

    Kislat, F; Beilicke, M; Krawczynski, H

    2014-01-01

    X-ray polarimetry promises to deliver unique information about the geometry of the inner accretion flow of astrophysical black holes and the nature of matter and electromagnetism in and around neutron stars. In this paper, we discuss the possibility to use Stokes parameters - a commonly used tool in radio, infrared, and optical polarimetry - to analyze the data from X-ray polarimeters such as scattering polarimeters and photoelectric effect polarimeters, which measure the linear polarization of the detected X-rays. Based on the azimuthal scattering angle (in the case of a scattering polarimeter) or the azimuthal component of the angle of the electron ejection (in the case of a photoelectric effect polarimeter), the Stokes parameters can be calculated for each event recorded in the detector. Owing to the additive nature of Stokes parameters, the analysis reduces to adding the Stokes parameters of the individual events and subtracting the Stokes parameters characterizing the background (if present). The main st...

  6. Infrared Spectra and Optical Constants of Astronomical Ices: II. Ethane and Ethylene

    CERN Document Server

    Hudson, R L; Moore, M H

    2015-01-01

    Infrared spectroscopic observations have established the presence of hydrocarbon ices on Pluto and other TNOs, but the abundances of such molecules cannot be deduced without accurate optical constants (n, k) and reference spectra. In this paper we present our recent measurements of near- and mid-infrared optical constants for ethane (C$_2$H$_6$) and ethylene (C$_2$H$_4$) in multiple ice phases and at multiple temperatures. As in our recent work on acetylene (C$_2$H$_2$), we also report new measurements of the index of refraction of each ice at 670 nm. Comparisons are made to earlier work where possible, and electronic versions of our new results are made available.

  7. Determining astronomical seeing conditions at Matjiesfontein by optical and turbulence methods

    Energy Technology Data Exchange (ETDEWEB)

    Nickola, M [Hartebeesthoek Radio Astronomy Observatory (HartRAO) Space Geodesy Programme, PO Box 443, Krugersdorp 1740 (South Africa); Esau, I [G.C. Rieber Climate Institute of the Nansen Environmental and Remote Sensing Center (NERSC), Thoermohlensgate 47, N-5006 Bergen (Norway); Djolov, G [University of Pretoria, Department of Geography, Geoinformatics and Meteorology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0002 (South Africa)

    2010-08-15

    Matjiesfontein in the Karoo has been proposed as a suitable location for a new fundamental space geodetic observatory. On-site geodetic equipment will include a Lunar Laser Ranger (LLR). LLR requires sub-arcsecond optical seeing conditions for delivery of high quality and quantity data. Seeing conditions at the Matjiesfontein site will be evaluated by making use of an automated seeing monitor and by modelling atmospheric turbulence with Large Eddy Simulation Nansen Center Improved Code (LESNIC).

  8. Optical Characterisation of Astronomical Submillimetre Receivers including ALMA Bands 5 and 9

    OpenAIRE

    Whale, Mark

    2010-01-01

    The primary concern of this thesis is the analysis of long wavelength quasioptical receiver systems operating within the Terahertz and submillimetre wavebands. Specific attention is paid to the front-end coupling optics of the Band 5 and Band 9 receiver channels of the Atacama Large Millimetre Array (ALMA). The theory of Gaussian Beam Mode Analysis (GBMA) is expanded and developed as the basic analytical tool for the work presented. This technique is utilised to model both clas...

  9. Magnetic liquid deformable mirrors for astronomical applications:Active correction of optical aberrations from lower-grade optics and support system

    CERN Document Server

    Borra, E F

    2012-01-01

    Deformable mirrors are increasingly used in astronomy. However, they still are limited in stroke for active correction of high amplitude optical aberrations. Magnetic Liquid deformable mirrors (MLDMs) are a new technology that has advantages of high-amplitude deformations and low costs. In this paper we demonstrate extremely high strokes and inter-actuator strokes achievable by MLDMs which can be used in astronomical instrumentation. In particular, we consider the use of such a mirror to suggest an interesting application for the next generation of large telescopes. We present a prototype 91-actuator deformable mirror made of a magnetic liquid (ferrofluid). This mirror uses a technique that linearizes the response of such mirrors by superimposing a large and uniform magnetic field to the magnetic field produced by an array of small coils. We discuss experimental results that illustrate the performance of MLDMs. A most interesting application of MLDMs comes from the fact they could be used to correct the aberr...

  10. Astronomical Science with Laser Guide Star Adaptive Optics: A Brief Review, a Current Snapshot, and a Bright Future

    CERN Document Server

    Liu, M C

    2006-01-01

    We briefly discuss the past, present, and future state of astronomical science with laser guide star adaptive optics (LGS AO). We present a tabulation of refereed science papers from LGS AO, amounting to a total of 23 publications as of May 2006. The first decade of LGS AO science (1995-2004) was marked by modest science productivity (~1 paper/year), as LGS systems were being implemented and commissioned. The last two years have seen explosive science growth (~1 paper/month), largely due to the new LGS system on the Keck II 10-meter telescope, and point to an exciting new era for high angular resolution science. To illustrate the achievable on-sky performance, we present an extensive collection of Keck LGS performance measurements from the first year of our brown dwarf near-IR imaging survey. We summarize the current strengths and weaknesses of LGS compared to Hubble Space Telescope, offer a list of desired improvements, and look forward to a bright future for LGS given its wide-scale implementation on large ...

  11. Radiation studies of optical and electronic components used in astronomical satellite studies

    Science.gov (United States)

    Becher, J.; Kernell, R. L.

    1981-01-01

    The synchronous orbit of the IUE carries the satellite through Earth's outer electron belt. A 40 mCi Sr90 source was used to simulate these electrons. A 5 mCi source of Co60 was used to simulate bremmstrahlung. A 10 MeV electron Linac and a 1.7 MeV electron Van de Graaf wer used to investigate the energy dependence of radiation effects and to perform radiations at a high flux rate. A 100 MeV proton cyclotron was used to simulate cosmic rays. Results are presented for three instrument systems of the IUE and measurements for specific components are reported. The three instrument systems were the ultraviolet converter, the fine error sensor (FES), and the SEC vidicon camera tube. The components were optical glasses, electronic components, silicon photodiodes, and UV window materials.

  12. Astronomical Cybersketching

    CERN Document Server

    Grego, Peter

    2009-01-01

    Outlines the techniques involved in making observational sketches and more detailed 'scientific' drawings of a wide variety of astronomical subjects using modern digital equipment; primarily PDAs and tablet PCs. This book also discusses about choosing hardware and software

  13. The effect of airborne dust on astronomical polarization measurements

    Science.gov (United States)

    Bailey, Jeremy; Ulanowski, Z.; Lucas, P. W.; Hough, J. H.; Hirst, E.; Tamura, M.

    2008-05-01

    In the past, it has generally been assumed that polarization observations made with ground-based telescopes are unaffected by the passage of light through the Earth's atmosphere. Here, we report observations with a new high-sensitivity astronomical polarimeter (PlanetPol) made during a Saharan dust event over the La Palma observatory in 2005 May that show excess linear polarization in the horizontal direction due to the passage of the starlight through the dust. The polarization reached a maximum value of 4.8 × 10-5 at 56° zenith distance and varied over five nights in proportion to the change in dust optical depth. Polarization of transmitted light (dichroism) does not occur for spherical or randomly oriented non-spherical particles. Thus, these results imply that some fraction of the dust grain population aligns with a preferred orientation. We use T-matrix models to demonstrate that the observed polarization direction implies a vertical orientation for the long axis of the particles. We suggest a possible mechanism for vertical orientation resulting from the electric field in the atmosphere. These results will need to be taken into account in the design and use of future instruments for high-sensitivity astronomical polarimetry. The results also indicate possible new approaches to studying aerosol particles and their effects on the Earth's atmosphere.

  14. Adaptive distributed Kalman filtering with wind estimation for astronomical adaptive optics.

    Science.gov (United States)

    Massioni, Paolo; Gilles, Luc; Ellerbroek, Brent

    2015-12-01

    In the framework of adaptive optics (AO) for astronomy, it is a common assumption to consider the atmospheric turbulent layers as "frozen flows" sliding according to the wind velocity profile. For this reason, having knowledge of such a velocity profile is beneficial in terms of AO control system performance. In this paper we show that it is possible to exploit the phase estimate from a Kalman filter running on an AO system in order to estimate wind velocity. This allows the update of the Kalman filter itself with such knowledge, making it adaptive. We have implemented such an adaptive controller based on the distributed version of the Kalman filter, for a realistic simulation of a multi-conjugate AO system with laser guide stars on a 30 m telescope. Simulation results show that this approach is effective and promising and the additional computational cost with respect to the distributed filter is negligible. Comparisons with a previously published slope detection and ranging wind profiler are made and the impact of turbulence profile quantization is assessed. One of the main findings of the paper is that all flavors of the adaptive distributed Kalman filter are impacted more significantly by turbulence profile quantization than the static minimum mean square estimator which does not incorporate wind profile information.

  15. Adaptive distributed Kalman filtering with wind estimation for astronomical adaptive optics.

    Science.gov (United States)

    Massioni, Paolo; Gilles, Luc; Ellerbroek, Brent

    2015-12-01

    In the framework of adaptive optics (AO) for astronomy, it is a common assumption to consider the atmospheric turbulent layers as "frozen flows" sliding according to the wind velocity profile. For this reason, having knowledge of such a velocity profile is beneficial in terms of AO control system performance. In this paper we show that it is possible to exploit the phase estimate from a Kalman filter running on an AO system in order to estimate wind velocity. This allows the update of the Kalman filter itself with such knowledge, making it adaptive. We have implemented such an adaptive controller based on the distributed version of the Kalman filter, for a realistic simulation of a multi-conjugate AO system with laser guide stars on a 30 m telescope. Simulation results show that this approach is effective and promising and the additional computational cost with respect to the distributed filter is negligible. Comparisons with a previously published slope detection and ranging wind profiler are made and the impact of turbulence profile quantization is assessed. One of the main findings of the paper is that all flavors of the adaptive distributed Kalman filter are impacted more significantly by turbulence profile quantization than the static minimum mean square estimator which does not incorporate wind profile information. PMID:26831389

  16. Conceptual design report of a compton polarimeter for CEBAF hall A

    Energy Technology Data Exchange (ETDEWEB)

    Bardin, G.; Cavata, C.; Neyret, D.; Frois, B.; Jorda, J.P.; Legoff, J.M.; Platchkov, S.; Steinmetz, L.; Juillard, M.; Authier, M.; Mangeot, P.; Rebourgeard, P.; Colombel, N.; Girardot, P.; Martinot, J.; Sellier, J.C.; Veyssiere, C. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee; Berthot, J.; Bertin, P.Y.; Breton, V.; Fonvieille, H.; Roblin, Y. [Institut National de Physique Nucleaire et de Physique des Particules (IN2P3), 75 - Paris (France); Chen, J.P. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

    1996-12-31

    This report describes the design of the Compton polarimeter for the Cebaf electron beam in End Station A. The method of Compton polarimeter is first introduced. It is shown that at CEBAF beam intensities, the use of standard visible LASER light gives too low counting rates. An amplification scheme of the LASER beam based on a high finesse optical cavity is proposed. Expected luminosities with and without such a cavity are given. The polarimeter setup, including a 4 dipole magnet chicane, a photon and an electron detector, is detailed. The various sources of systematic error on the electron beam polarization measurement are discussed. (author). 82 refs.

  17. Soft x-ray polarimeter laboratory tests

    Science.gov (United States)

    Murphy, Kendrah D.; Marshall, Herman L.; Schulz, Norbert S.; Jenks, Kevin; Sommer, Sophie J. B.; Marshall, Eric A.

    2010-07-01

    Multilayer-coated optics can strongly polarize X-rays and are central to a new design of a broad-band, soft X-ray polarimeter. We have begun laboratory work to verify the performance of components that could be used in future soft X-ray polarimetric instrumentation. We have reconfigured a 17 meter beamline facility, originally developed for testing transmission gratings for Chandra, to include a polarized X-ray source, an X-ray-dispersing transmission grating, and a multilayer-coated optic that illuminates a CCD detector. The X-rays produced from a Manson Model 5, multi-anode source are polarized by a multilayer-coated flat mirror. The current configuration allows for a 180 degree rotation of the source in order to rotate the direction of polarization. We will present progress in source characterization and system modulation measurements as well as null and robustness tests.

  18. Astronomical Observatory

    Directory of Open Access Journals (Sweden)

    Mansi Khanna

    2014-03-01

    Full Text Available This photograph was taken at Jantar Mantar, one of India’s most famous astronomical observatories, located in Central Delhi. It was built in 1724 by Maharaja Jai Singh II of Jaipur, who then went on to build other observatories in Jaipur, Varanasi, and Mathura. It was used to make astronomical tables and predict movements of the planets and the sun. Its name is derived from yantra meaning instruments and mantar meaning formula.Due to the construction of several high rise buildings around the monument, it is no longer used for astronomical purposes. It however continues to be one of the biggest tourist attractions of the capital city. 

  19. Astronomical Polarimetry

    Science.gov (United States)

    Tinbergen, Jaap

    1996-09-01

    This handy volume provides a clear, comprehensive and concise introduction to astronomical polarimetry at all wavelengths. Starting from first principles and a simple physical picture of polarized radiation, the author introduces the reader to all the key topics, including Stokes parameters, applications of polarimetry in astronomy, polarization algebra, polarization errors and calibration methods, and a selection of instruments (from radio to X-ray). The author rounds off the book with a number of useful case studies, a collection of exercises, an extensive list of further reading and an informative index. This review of all aspects of astronomical polarization provides both an essential introduction for graduate students, and a valuable reference for practicing astronomers.

  20. Astronomical Receiver Modelling Using Scattering Matrices

    CERN Document Server

    King, O G; Copley, C; Davis, R J; Leahy, J P; Leech, J; Muchovej, S J C; Pearson, T J; Taylor, Angela C

    2014-01-01

    Proper modelling of astronomical receivers is vital: it describes the systematic errors in the raw data, guides the receiver design process, and assists data calibration. In this paper we describe a method of analytically modelling the full signal and noise behaviour of arbitrarily complex radio receivers. We use electrical scattering matrices to describe the signal behaviour of individual components in the receiver, and noise correlation matrices to describe their noise behaviour. These are combined to produce the full receiver model. We apply this approach to a specified receiver architecture: a hybrid of a continous comparison radiometer and correlation polarimeter designed for the C-Band All-Sky Survey. We produce analytic descriptions of the receiver Mueller matrix and noise temperature, and discuss how imperfections in crucial components affect the raw data. Many of the conclusions drawn are generally applicable to correlation polarimeters and continuous comparison radiometers.

  1. Astronomical Ecosystems

    Science.gov (United States)

    Neuenschwander, D. E.; Finkenbinder, L. R.

    2004-05-01

    Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

  2. DoFP polarimeter based polarization microscope for biomedical applications

    Science.gov (United States)

    Chang, Jintao; He, Honghui; He, Chao; Ma, Hui

    2016-03-01

    Polarization microscope is a useful technique to observe the optical anisotropic nature of biomedical specimens and provide more microstructural information than the conventional microscope. In this paper, we present a division of focal plane (DoFP) polarimeter based polarization microscope which is capable of imaging both the Stokes vector and the 3×4 Mueller matrix. The Mueller matrix measurement can help us completely understand the polarization properties of the sample and the Stokes vector measurement is a simultaneous technology. First, we calibrate a DoFP polarimeter using the polarization data reduction method for accurate Stokes vector measurements. Second, as the Stokes vector computation for all pixels using the calibrated instrument matrix is usually time consuming, we develop a GPU acceleration algorithm for real time Stokes vector calculations. Third, based on the accurate and fast Stokes vector calculation, we present an optimal 4-states of polarization (4-SoP) illumination scheme for Mueller matrix measurement using the DoFP polarimeter. Finally, we demonstrate the biomedical applications of the DoFP polarimeter based polarization microscope. Experiment results show that the characteristic features of many biomedical samples can be observed in the "polarization staining" images using the circularly polarized light as illumination. In this way, combined with GPU acceleration algorithm, the DoFP polarization microscope has the capacity for real time polarization monitoring of dynamic processes in biological samples.

  3. Feedhorn-coupled TES polarimeter camera modules at 150 GHz for CMB polarization measurements with SPTpol

    CERN Document Server

    Henning, J W; Aird, K A; Austermann, J E; Beall, J A; Becker, D; Benson, B A; Bleem, L E; Britton, J; Carlstrom, J E; Chang, C L; Cho, H -M; Crawford, T M; Crites, A T; Datesman, A; de Haan, T; Dobbs, M A; Everett, W; Ewall-Wice, A; George, E M; Halverson, N W; Harrington, N; Hilton, G C; Holzapfel, W L; Hubmayr, J; Irwin, K D; Karfunkle, M; Keisler, R; Kennedy, J; Lee, A T; Leitch, E; Li, D; Lueker, M; Marrone, D P; McMahon, J J; Mehl, J; Meyer, S S; Montgomery, J; Montroy, T E; Nagy, J; Natoli, T; Nibarger, J P; Niemack, M D; Novosad, V; Padin, S; Pryke, C; Reichardt, C L; Ruhl, J E; Saliwanchik, B R; Sayre, J T; Schaffer, K K; Shirokoff, E; Story, K; Tucker, C; Vanderlinde, K; Vieira, J D; Wang, G; Williamson, R; Yefremenko, V; Yoon, K W; Young, E; 10.1117/12.927172

    2012-01-01

    The SPTpol camera is a dichroic polarimetric receiver at 90 and 150 GHz. Deployed in January 2012 on the South Pole Telescope (SPT), SPTpol is looking for faint polarization signals in the Cosmic Microwave Background (CMB). The camera consists of 180 individual Transition Edge Sensor (TES) polarimeters at 90 GHz and seven 84-polarimeter camera modules (a total of 588 polarimeters) at 150 GHz. We present the design, dark characterization, and in-lab optical properties of the 150 GHz camera modules. The modules consist of photolithographed arrays of TES polarimeters coupled to silicon platelet arrays of corrugated feedhorns, both of which are fabricated at NIST-Boulder. In addition to mounting hardware and RF shielding, each module also contains a set of passive readout electronics for digital frequency-domain multiplexing. A single module, therefore, is fully functional as a miniature focal plane and can be tested independently. Across the modules tested before deployment, the detectors average a critical temp...

  4. The San Fernando Observatory video Stokes polarimeter

    Science.gov (United States)

    Richter, P. H.; Zeldin, L. K.; Loftin, T. A.

    1985-01-01

    A study was conducted to determine the suitability of the San Fernando Observatory's 61 cm (24 inch) aperture vacuum solar telescope and 3 m (118 inch) focal length vacuum spectroheliograph for Stokes Polarimetry measurements. The polarization characteristics of these two instruments was measured by determining their Mueller matrices as a function of telescope orientation, field angle, wavelength, grating type, and position of the measuring beam in the telescope entrance window. In general, the polarizing and depolarizing properties are small so that inversion of the system Mueller matrix will permit the accurate measurement of Stokes profiles for vector magnetic field determination. A proposed polarimeter design based on the use of a TV camera system to simultaneously scan six different polarization components of a given line profile is described. This design, which uses no rotating optics or electronic modulators and makes efficient use of the available irradiance, promises to yield high quality vector magnetograms.

  5. Field deployable pushbroom hyperspectral imagining polarimeter

    Science.gov (United States)

    Lowenstern, Mariano; Kudenov, Michael W.

    2016-05-01

    Hyperspectral polarimetry is demonstrated to measure the spectrum and polarization state of a scene. This information is important to identify material properties for applications such as remote sensing and agricultural monitoring, among others. We report the design and performance of a ruggedized, field deployable Hyperspectral Polarimeter Imaging (HPI) system over the VIS to NIR range (450-800 nm). An entrance slit was used to sample a scene in a pushbroom scanning mode, sampling over a 30 degree vertical by 110 degree horizontal field of view. Furthermore, athermalized achromatic retarders were implemented in a channel spectrum generator to measure the linear Stoke vectors. This paper reports the mechanical and optical layout of the system and its peripherals. We present preliminary spectral and polarimetry calibration techniques as well as testing results in field environments.

  6. Terrace retro-reflector array for poloidal polarimeter on ITER.

    Science.gov (United States)

    Imazawa, R; Kawano, Y; Ono, T; Kusama, Y

    2011-02-01

    A new concept of a terrace retro-reflector array (TERRA) as part of the poloidal polarimeter for ITER is proposed in this paper. TERRA reflects a laser light even from a high incident angle in the direction of the incident-light path, while a conventional retro-reflector array cannot. Besides, TERRA can be installed in a smaller space than a corner-cube retro-reflector. In an optical sense, TERRA is equivalent to a Littrow grating, the blaze angle of which varies, depending on the incident angle. The reflected light generates a bright and dark fringe, and the bright fringe is required to travel along the incident-light path to achieve the objects of laser-aided diagnostics. In order to investigate the propagation properties of laser light reflected by TERRA, we have developed a new diffraction formula. Conditions for the propagation of the bright fringe in the direction of the incident light have been obtained using the Littrow grating model and have been confirmed in a simulation applying the new diffraction formula. Finally, we have designed laser transmission optics using TERRA for the ITER poloidal polarimeter and have calculated the light propagation of the system. The optical design obtains a high transmission efficiency, with 88.6% of the incident power returned. These results demonstrate the feasibility of applying TERRA to the ITER poloidal polarimeter.

  7. Final Technical Report for Interagency Agreement No. DE-SC0005453 “Characterizing Aerosol Distributions, Types, and Optical and Microphysical Properties using the NASA Airborne High Spectral Resolution Lidar (HSRL) and the Research Scanning Polarimeter (RSP)”

    Energy Technology Data Exchange (ETDEWEB)

    Hostetler, Chris [NASA Langley Research Center, Hampton, VA (United States); Ferrare, Richard [NASA Langley Research Center, Hampton, VA (United States)

    2015-01-13

    Measurements of the vertical profile of atmospheric aerosols and aerosol optical and microphysical characteristics are required to: 1) determine aerosol direct and indirect radiative forcing, 2) compute radiative flux and heating rate profiles, 3) assess model simulations of aerosol distributions and types, and 4) establish the ability of surface and space-based remote sensors to measure the indirect effect. Consequently the ASR program calls for a combination of remote sensing and in situ measurements to determine aerosol properties and aerosol influences on clouds and radiation. As part of our previous DOE ASP project, we deployed the NASA Langley airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 King Air aircraft during major field experiments in 2006 (MILAGRO and MaxTEX), 2007 (CHAPS), 2009 (RACORO), and 2010 (CalNex and CARES). The HSRL provided measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm). These measurements were typically made in close temporal and spatial coincidence with measurements made from DOE-funded and other participating aircraft and ground sites. On the RACORO, CARES, and CalNEX missions, we also deployed the NASA Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP). RSP provided intensity and degree of linear polarization over a broad spectral and angular range enabling column-average retrievals of aerosol optical and microphysical properties. Under this project, we analyzed observations and model results from RACORO, CARES, and CalNex and accomplished the following objectives. 1. Identified aerosol types, characterize the vertical distribution of the aerosol types, and partition aerosol optical depth by type, for CARES and CalNex using HSRL data as we have done for previous missions. 2. Investigated aerosol microphysical and macrophysical properties using the RSP. 3. Used the aerosol backscatter and extinction profiles measured by the HSRL

  8. A multi-spectral band stellar photo-polarimeter

    CERN Document Server

    Srinivasulu, G; Muneer, S; Mekkaden, M V; Jayavel, N; Somashekar, M R; Sagayanathan, K; Ramamoorthy, S; Rosario, M J; Jayakumar, K

    2015-01-01

    We designed and built a new astronomical photo-polarimeter that can measure linear polarization simultaneously in three spectral bands. It has a Calcite beamdisplacement prism as the analyzer. The ordinary and extra-ordinary emerging beams in each spectral bands are quasi-simultaneously detected by the same photomultiplier by using a high speed rotating chopper. A rotating superachromatic Pancharatnam halfwave plate is used to modulate the light incident on the analyzer. The spectral bands are isolated using appropriate dichroic and glass filters. We show that the reduction of 50% in the efficiency of the polarimeter because of the fact that the intensities of the two beams are measured alternately is partly compensated by the reduced time to be spent on the observation of the sky background. The use of a beam-displacement prism as the analyzer completely removes the polarization of background skylight, which is a major source of error during moonlit nights, especially, in the case of faint stars. The field t...

  9. On the emissivity of wire-grid polarizers for astronomical observations at mm-wavelengths

    CERN Document Server

    Schillaci, Alessandro; Alessandro, Giuseppe D'; de Bernardis, Paolo; Masi, Silvia

    2012-01-01

    We have measured, using a custom setup, the emissivity of metallic wire-grids, suitable for polarimeters and interferometers at mm and far infrared wavelengths. We find that the effective emissivity of these devices is of the order of a few %, depending on fabrication technology and aging. We discuss their use in astronomical instruments, with special attention to Martin Puplett Interferometers in low-background applications, like astronomical observations of the Cosmic Microwave Background.

  10. Using commercial amateur astronomical spectrographs

    CERN Document Server

    Hopkins, Jeffrey L

    2014-01-01

    Amateur astronomers interested in learning more about astronomical spectroscopy now have the guide they need. It provides detailed information about how to get started inexpensively with low-resolution spectroscopy, and then how to move on to more advanced  high-resolution spectroscopy. Uniquely, the instructions concentrate very much on the practical aspects of using commercially-available spectroscopes, rather than simply explaining how spectroscopes work. The book includes a clear explanation of the laboratory theory behind astronomical spectrographs, and goes on to extensively cover the practical application of astronomical spectroscopy in detail. Four popular and reasonably-priced commercially available diffraction grating spectrographs are used as examples. The first is a low-resolution transmission diffraction grating, the Star Analyser spectrograph. The second is an inexpensive fiber optic coupled bench spectrograph that can be used to learn more about spectroscopy. The third is a newcomer, the ALPY ...

  11. Anti-aliasing Wiener filtering for wave-front reconstruction in the spatial-frequency domain for high-order astronomical adaptive-optics systems

    CERN Document Server

    Correia, Carlos M

    2014-01-01

    Computationally-efficient wave-front reconstruction techniques for astronomical adaptive optics systems have seen a great development in the past decade. Algorithms developed in the spatial-frequency (Fourier) domain have gathered large attention specially for high-contrast imaging systems. In this paper we present the Wiener filter (resulting in the maximization of the Strehl-ratio) and further develop formulae for the anti-aliasing Wiener filter that optimally takes into account high-order wave-front terms folded in-band during the sensing (i.e. discrete sampling) process. We employ a continuous spatial-frequency representation for the forward measurement operators and derive the Wiener filter when aliasing is explicitly taken into account. We further investigate and compare to classical estimates using least-squares filters the reconstructed wave-front, measurement noise and aliasing propagation coefficients as a function of the system order. Regarding high-contrast systems, we provide achievable performan...

  12. A high energy photon polarimeter for astrophysics

    OpenAIRE

    Eingorn, Maxim; Fernando, Lakma; Vlahovic, Branislav; Ilie, Cosmin; Wojtsekhowski, Bogdan; Urciuoli, Guido Maria; De Persio, Fulvio; Meddi, Franco

    2015-01-01

    A high-energy photon polarimeter for astrophysics studies in the energy range from 20 MeV to 1000 MeV is considered. The proposed concept uses a stack of silicon micro-strip detectors where they play the roles of both a converter and a tracker. The purpose of this paper is to outline the parameters of such a polarimeter and to estimate the productivity of measurements. Our study supported by a Monte Carlo simulation shows that with a one-year observation period the polarimeter will provide 6%...

  13. Novel Algorithms for Astronomical Plate Analyses

    Indian Academy of Sciences (India)

    Rene Hudec; Lukas Hudec

    2011-03-01

    Powerful computers and dedicated software allow effective data mining and scientific analyses in astronomical plate archives. We give and discuss examples of newly developed algorithms for astronomical plate analyses, e.g., searches for optical transients, as well as for major spectral and brightness changes.

  14. A high energy photon polarimeter for astrophysics

    CERN Document Server

    Eingorn, Maxim; Vlahovic, Branislav; Wojtsekhowski, Bogdan; Urciuoli, Guido Maria; De Persio, Fulvio; Meddi, Franco

    2015-01-01

    A high-energy photon polarimeter for astrophysics studies in the energy range from 20 MeV to 1000 MeV is considered. The proposed concept uses a stack of silicon micro-strip detectors where they play the roles of both a converter and a tracker. The purpose of this paper is to outline the parameters of such a polarimeter and to estimate the productivity of measurements. Our study supported by a Monte Carlo simulation shows that with a one-year observation period the polarimeter will provide 5.5 % accuracy of the polarization degree for a photon energy of 100 MeV, which would be a significant advance relative to the currently explored energy range of a few MeV. The proposed polarimeter design could easily be adjusted to the specific photon energy range to maximize efficiency if needed.

  15. Polarimeter for high energy photons

    Science.gov (United States)

    Wojtsekhowski, Bogdan; Vlahovic, Branislav; Tedeschi, David; Danagulian, Samuel; Litvienko, Vladimir; Pinayev, Igor

    1999-11-01

    The physics program at TJNAF includes fundamental experiments with polarized photon beam in few GeV energy range. Development of the Polarimeter for use in Hall B experiments is the subject of present abstract. We have proposed to take advantage of the recent progress in silicon micro strip detectors for measurement of the geometry and angle correlation in electron positron pair production from an amorphous converter. A detailed analysis of the setup including MC simulation shows an experimental asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of the photon energies. This asymmetry value is confirmed by our experimental results obtained using 100 percent polarized 40 MeV γ rays at Duke FEL.

  16. The Compton polarimeter at ELSA

    International Nuclear Information System (INIS)

    In order to measure the degree of transverse polarization of the stored electron beam in the Electron Stretcher Accelerator ELSA a compton polarimeter is built up. The measurement is based on the polarization dependent cross section for the compton scattering of circular polarized photons off polarized electrons. Using a high power laser beam and detecting the scattered photons a measuring time of two minutes with a statistical error of 5% is expected from numerical simulations. The design and the results of a computer controlled feedback system to enhance the laser beam stability at the interaction point in ELSA are presented. The detection of the scattered photons is based on a lead converter and a silicon-microstrip detector. The design and test results of the detector module including readout electronic and computer control are discussed. (orig.)

  17. Extended Commissioning and Calibration of the Dual-Beam Imaging Polarimeter

    CERN Document Server

    Masiero, Joseph; Harrington, David; Lin, Haosheng

    2008-01-01

    In our previous paper (Masiero et al. 2007) we presented the design and initial calibrations of the Dual-Beam Imaging Polarimeter (DBIP), a new optical instrument for the University of Hawaii's 2.2 m telescope on the summit of Mauna Kea, Hawaii. In this followup work we discuss our full-Stokes mode commissioning including crosstalk determination and our typical observing methodology.

  18. COMMISSIONING CNI PROTON POLARIMETERS IN RHIC

    International Nuclear Information System (INIS)

    Two polarimeters based on proton carbon elastic scattering in the Coulomb Nuclear Interference (CNI) region have been installed and commissioned in the Blue and Yellow rings of RHIC during the first RHIC polarized proton collider run. Each polarimeter consists of ultra-thin carbon targets and six silicon detectors. With newly developed wave form digitizers, they provide fast and reliable polarization information for both rings

  19. Next Generation X-ray Polarimeter

    Science.gov (United States)

    Hill-Kittle, Joe

    sources that were previously unobtainable within realistic observation times e.g. Active Galactic Nuclei (AGN). Standard photoelectric X-ray polarimeter designs are both quantum efficiency (QE) limited and challenging to calibrate due to diffusion of electron signal as it drifts through the gas. Drifting negative ions decreases diffusion to the thermal limit thereby decoupling sensitivity from drift distance and enabling larger detector areas that can be at the focus of larger diameter mirrors and single reflection concentrator optics. NITPCs also allow the selection of constituent gasses and pressures to be based on the optimization of modulation and QE rather than diffusion properties. This versatility enables a large improvement in sensitivity without driving cost and with only moderate increase to mass and power of the detector and/or instrument. Furthermore, the energy band of NGXP will be tunable to maximize the science return. Following the efforts of this proposal NGXP will be proposed as sounding rocket experiment and as a candidate instrument for future opportunities. The GSFC polarimeter group has demonstrated NITPCs for several detector concepts. This proposal leverages the previous effort and team expertise with goals to establish the NITPC as the baseline for narrow field observations of faint persistent sources and to improve the technology readiness of associated technologies such as stainless steel gas electron multipliers and finer readout pitch.

  20. Modelling of the signal processing electronics of JET interferometer-polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Gelfusa, M., E-mail: gelfusa@ing.uniroma2.i [Associazione EURATOM-ENEA - University of Rome ' Tor Vergata' , Roma (Italy); Brombin, M. [Consorzio RFX Associazione EURATOM-ENEA per la Fusione, Corso Stati Uniti 4, 35127 Padova (Italy); Padova University, Industrial Engineering Department, via Venezia 1, 35131 Padova (Italy); Gaudio, P. [Associazione EURATOM-ENEA - University of Rome ' Tor Vergata' , Roma (Italy); Boboc, A. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Murari, A. [Consorzio RFX Associazione EURATOM-ENEA per la Fusione, Corso Stati Uniti 4, 35127 Padova (Italy); Orsitto, F.P. [Associazione EURATOM - ENEA Centro Ricerche Frascati, 00044 Frascati (Italy)

    2010-11-11

    The present electronics of JET Far Infrared polarimeter was commissioned in 2002. Due to the fact that in the last years the diagnostic has been configured to measure routinely both the Faraday Rotation angle and the Cotton-Mouton angle with a different optical set-up, it becomes important to check the performance of the analog phase sensitive electronics that is the core of the polarimeter. Therefore a simulator for the JET FIR polarimeter analog electronics has been developed with Simulink and with Matlab in order to completely characterize its behaviour, assess its performance and determine its impact on the absolute calibration of the diagnostic. The presented results indicate the electronic devices are working within their design specifications.

  1. Choosing and using astronomical filters

    CERN Document Server

    Griffiths, Martin

    2014-01-01

    As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

  2. Biographical encyclopedia of astronomers

    CERN Document Server

    Trimble, Virginia; Williams, Thomas; Bracher, Katherine; Jarrell, Richard; Marché, Jordan; Palmeri, JoAnn; Green, Daniel

    2014-01-01

    The Biographical Encyclopedia of Astronomers is a unique and valuable resource for historians and astronomers alike. It includes approx. 1850 biographical sketches on astronomers from antiquity to modern times. It is the collective work of 430 authors edited by an editorial board of 8 historians and astronomers. This reference provides biographical information on astronomers and cosmologists by utilizing contemporary historical scholarship. The fully corrected and updated second edition adds approximately 300 biographical sketches. Based on ongoing research and feedback from the community, the new entries will fill gaps and provide expansions. In addition, greater emphasis on Russo phone astronomers and radio astronomers is given. Individual entries vary from 100 to 1500 words, including the likes of the super luminaries such as Newton and Einstein, as well as lesser-known astronomers like Galileo's acolyte, Mario Guiducci.

  3. Anti-aliasing Wiener filtering for wave-front reconstruction in the spatial-frequency domain for high-order astronomical adaptive-optics systems.

    Science.gov (United States)

    Correia, Carlos M; Teixeira, Joel

    2014-12-01

    Computationally efficient wave-front reconstruction techniques for astronomical adaptive-optics (AO) systems have seen great development in the past decade. Algorithms developed in the spatial-frequency (Fourier) domain have gathered much attention, especially for high-contrast imaging systems. In this paper we present the Wiener filter (resulting in the maximization of the Strehl ratio) and further develop formulae for the anti-aliasing (AA) Wiener filter that optimally takes into account high-order wave-front terms folded in-band during the sensing (i.e., discrete sampling) process. We employ a continuous spatial-frequency representation for the forward measurement operators and derive the Wiener filter when aliasing is explicitly taken into account. We further investigate and compare to classical estimates using least-squares filters the reconstructed wave-front, measurement noise, and aliasing propagation coefficients as a function of the system order. Regarding high-contrast systems, we provide achievable performance results as a function of an ensemble of forward models for the Shack-Hartmann wave-front sensor (using sparse and nonsparse representations) and compute point-spread-function raw intensities. We find that for a 32×32 single-conjugated AOs system the aliasing propagation coefficient is roughly 60% of the least-squares filters, whereas the noise propagation is around 80%. Contrast improvements of factors of up to 2 are achievable across the field in the H band. For current and next-generation high-contrast imagers, despite better aliasing mitigation, AA Wiener filtering cannot be used as a standalone method and must therefore be used in combination with optical spatial filters deployed before image formation actually takes place.

  4. A beam-displacement prism based, three band stellar photo-polarimeter

    CERN Document Server

    Raveendran, A V; Muneer, S; Mekkaden, M V; Jayavel, N; Somashekar, M R; Sagayanathan, K; Ramamoorthy, S; Rosario, M J; Jayakumar, K

    2015-01-01

    A new astronomical photo-polarimeter that can measure linear polarization of point sources simultaneously in three spectral bands was designed and built in Indian Institute of Astrophysics. The polarimeter has a Calcite beam-displacement prism as the analyzer. The ordinary and extra-ordinary emerging beams in each spectral band are quasi-simultaneously detected by the same photomultiplier by using a high speed rotating chopper. The effective chopping frequency can be set to as high as 200 Hz. A rotating superachromatic Pancharatnam halfwave plate is used to modulate the light incident on the analyzer. The spectral bands are isolated using appropriate dichroic and glass filters. A detailed analysis shows that the reduction of 50% in the efficiency of the polarimeter because of the fact that the intensities of the two beams are measured alternately is partly compensated by the reduced time to be spent on the observation of the sky background. The position angle of polarization produced by the Glan-Taylor prism ...

  5. Liquid Water Cloud Properties During the Polarimeter Definition Experiment (PODEX)

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Wasilewski, Andrzei P.; Ackerman, Andrew S.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Platnick, Steven; Arnold, George; Van Diedenhoven, Bastiaan; Chowdhary, Jacek; Ottaviani, Matteo; Knobelspiesse, Kirk D.

    2015-01-01

    We present retrievals of water cloud properties from the measurements made by the Research Scanning Polarimeter (RSP) during the Polarimeter Definition Experiment (PODEX) held between January 14 and February 6, 2013. The RSP was onboard the high-altitude NASA ER-2 aircraft based at NASA Dryden Aircraft Operation Facility in Palmdale, California. The retrieved cloud characteristics include cloud optical thickness, effective radius and variance of cloud droplet size distribution derived using a parameter-fitting technique, as well as the complete droplet size distribution function obtained by means of Rainbow Fourier Transform. Multi-modal size distributions are decomposed into several modes and the respective effective radii and variances are computed. The methodology used to produce the retrieval dataset is illustrated on the examples of a marine stratocumulus deck off California coast and stratus/fog over California's Central Valley. In the latter case the observed bimodal droplet size distributions were attributed to two-layer cloud structure. All retrieval data are available online from NASA GISS website.

  6. The Detector System for the Stratospheric Kinetic Inductance Polarimeter (SKIP)

    CERN Document Server

    Johnson, B R; Araujo, D; Bradford, K J; Chapman, D; Didier, J; Doyle, S; Eriksen, H K; Flanigan, D; Groppi, C; Hillbrand, S; Jones, G; Limon, M; Mauskopf, P; McCarrick, H; Miller, A; Mroczkowski, T; Reichborn-Kjennerud, B; Smiley, B; Sobrin, J; Wehus, I K; Zmuidzinas, J

    2013-01-01

    We discuss the detector system for the Stratospheric Kinetic Inductance Polarimeter (SKIP). SKIP is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background and Galactic dust emission by observing 1133 square degrees of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors (LEKIDs). The LEKIDs will be maintained at 100 mK with an adiabatic demagnetization refrigerator. The polarimeter operates in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcmin FWHM beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical ...

  7. PlanetPol: A Very High Sensitivity Polarimeter

    Science.gov (United States)

    Hough, J. H.; Lucas, P. W.; Bailey, J. A.; Tamura, M.; Hirst, E.; Harrison, D.; Bartholomew-Biggs, M.

    2006-09-01

    We have built and used on several occasions an optical broadband stellar polarimeter, PlanetPol, which employs photoelastic modulators and avalanche photodiodes and achieves a photon-noise-limited sensitivity of at least 1 in 106 in fractional polarization. Observations of a number of polarized standards taken from the literature show that the accuracy of polarization measurements is ~1%. We have developed a method for accurately measuring the polarization of altitude-azimuth mounted telescopes by observing bright nearby stars at different parallactic angles, and we find that the on-axis polarization of the William Herschel Telescope is typically ~15 × 10-6, measured with an accuracy of a few parts in 107. The nearby stars (distance less than 32 pc) are found to have very low polarizations, typically a few ×10-6, indicating that very little interstellar polarization is produced close to the Sun and that their intrinsic polarization is also low. Although the polarimeter can be used for a wide range of astronomy, the very high sensitivity was set by the goal of detecting the polarization signature of unresolved extrasolar planets.

  8. Design of channeled partial Mueller matrix polarimeters.

    Science.gov (United States)

    Alenin, Andrey S; Scott Tyo, J

    2016-06-01

    In this paper, we introduce a novel class of systems called channeled partial Mueller matrix polarimeters (c-pMMPs). Their analysis benefits greatly by drawing from the concepts of generalized construction of channeled polarimeters as described by the modulation matrix. The modulation matrix resembles that of the data reduction method of a conventional polarimeter, but instead of using Mueller vectors as the bases, attention is focused on the Fourier properties of the measurement conditions. By leveraging the understanding of the measurement's structure, its decomposition can be manipulated to reveal noise resilience and information about the polarimeter's ability to measure the aspect of polarization that are important for any given task. We demonstrate the theory with a numerical optimization that designs c-pMMPs for the task of monitoring the damage state of a material as presented earlier by Hoover and Tyo [Appl. Opt.46, 8364 (2007)APOPAI0003-693510.1364/AO.46.008364]. We select several example systems that produce a fewer-than-full-system number of channels yet retain the ability to discriminate objects of interest. Their respective trade-offs are discussed. PMID:27409432

  9. HAWCPol: a first-generation far-infrared polarimeter for SOFIA

    Science.gov (United States)

    Dowell, C. Darren; Cook, Brant T.; Harper, D. Al; Lin, Lung-Sheng; Looney, Leslie W.; Novak, Giles; Stephens, Ian; Berthoud, Marc; Chuss, David T.; Crutcher, Richard M.; Dotson, Jessie L.; Hildebrand, Roger H.; Houde, Martin; Jones, Terry J.; Krejny, Megan; Lazarian, Alexandre; Moseley, S. Harvey; Tassis, Kostas; Vaillancourt, John E.; Werner, Michael W.

    2010-07-01

    We describe our ongoing project to build a far-infrared polarimeter for the HAWC instrument on SOFIA. Far-IR polarimetry reveals unique information about magnetic fields in dusty molecular clouds and is an important tool for understanding star formation and cloud evolution. SOFIA provides flexible access to the infrared as well as good sensitivity to and angular resolution of continuum emission from molecular clouds. We are making progress toward outfitting HAWC, a first-generation SOFIA camera, with a four-band polarimeter covering 50 to 220 microns wavelength. We have chosen a conservative design which uses quartz half-wave plates continuously rotating at ~0.5 Hz, ball bearing suspensions, fixed wire-grid polarizers, and cryogenic motors. Design challenges are to fit the polarimeter into a volume that did not originally envision one, to minimize the heating of the cryogenic optics, and to produce negligible interference in the detector system. Here we describe the performance of the polarimeter measured at cryogenic temperature as well as the basic method we intend for data analysis. We are on track for delivering this instrument early in the operating lifetime of SOFIA.

  10. Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a Polarized Hard X-Ray Beam

    CERN Document Server

    Bloser, P F; McConnell, M L; Macri, J R; Bancroft, C M; Connor, T P; Ryan, J M

    2008-01-01

    The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module containing a single CsI(Na) calorimeter element, at the center of the MAPMT, surrounded by 60 plastic elements. The prototype has been combined with custom readout electronics and software to create a complete "engineering model" of the GRAPE...

  11. Atmospheric Scintillation in Astronomical Photometry

    CERN Document Server

    Osborn, J; Dhillon, V S; Wilson, R W

    2015-01-01

    Scintillation noise due to the Earth's turbulent atmosphere can be a dominant noise source in high-precision astronomical photometry when observing bright targets from the ground. Here we describe the phenomenon of scintillation from its physical origins to its effect on photometry. We show that Young's (1967) scintillation-noise approximation used by many astronomers tends to underestimate the median scintillation noise at several major observatories around the world. We show that using median atmospheric optical turbulence profiles, which are now available for most sites, provides a better estimate of the expected scintillation noise and that real-time turbulence profiles can be used to precisely characterise the scintillation noise component of contemporaneous photometric measurements. This will enable a better understanding and calibration of photometric noise sources and the effectiveness of scintillation correction techniques. We also provide new equations for calculating scintillation noise, including ...

  12. Astronomical pipeline processing using fuzzy logic

    Science.gov (United States)

    Shamir, Lior

    In the past few years, pipelines providing astronomical data have been becoming increasingly important. The wide use of robotic telescopes has provided significant discoveries, and sky survey projects such as SDSS and the future LSST are now considered among the premier projects in the field astronomy. The huge amount of data produced by these pipelines raises the need for automatic processing. Astronomical pipelines introduce several well-defined problems such as astronomical image compression, cosmic-ray hit rejection, transient detection, meteor triangulation and association of point sources with their corresponding known stellar objects. We developed and applied soft computing algorithms that provide new or improved solutions to these growing problems in the field of pipeline processing of astronomical data. One new approach that we use is fuzzy logic-based algorithms, which enables the automatic analysis of the astronomical pipelines and allows mining the data for not-yet-known astronomical discoveries such as optical transients and variable stars. The developed algorithms have been tested with excellent results on the NightSkyLive sky survey, which provides a pipeline of 150 astronomical pictures per hour, and covers almost the entire global night sky.

  13. 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.

  14. Fast Solar Polarimeter: First Light Results

    Science.gov (United States)

    Krishnappa, N.; Feller, A.; Iglesia, F. A.; Solanki, S.

    2013-12-01

    Accurate measurements of magnetic fields on the Sun are crucial to understand various physical processes that take place in the solar atmosphere such as solar eruptions, coronal heating, solar wind acceleration, etc. The Fast Solar Polarimeter (FSP) is a new instrument that is being developed to probe magnetic fields on the Sun. One of the main goals of this polarimeter is to carry out high precision spectropolarimetric observations with spatial resolution close to the telescope diffraction limit. The polarimeter is based on pnCCD technology with split frame transfer and simultaneous multi-channel readout, resulting in frame rate upto 1 kHz. The FSP prototype instrument uses a small format pnCCD of 264x264 pixels which has been developed by PNSensor and by the semiconductor lab of the Max Planck Society. The polarization modulator is based on two ferro-electric liquid crystals (FLCs) interlaced between two static retarders. The first solar observations have been carried out with this prototype during May-June, 2013 at German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands, Spain. Here we present the instrument performance assessments and the first results on the magnetic field measurements. Further, we briefly discuss about the next phase of FSP which will be a dual beam system with 1k x 1k CCDs.

  15. Fast Solar Polarimeter: Prototype Characterization and First Results

    Science.gov (United States)

    Iglesias, F. A.; Feller, A.; Krishnappa, N.; Solanki, S. K.

    2016-04-01

    Due to the differential and non-simultaneous nature of polarization measurements, seeing induced crosstalk (SIC) and seeing limited spatial resolution can easily counterbalance the benefits of solar imaging polarimetry from the ground. The development of instrumental techniques to treat these issues is necessary to fully exploit the next generation of large-aperture solar facilities, and maintain ground-based data at a competitive level with respect to its space-based counterpart. In particular, considering that many open questions in modern solar physics demand data with challenging specifications of resolution and polarimetric sensitivity that can only be achieved with large telescope apertures (Stenflo 1999). Even if state-of-the-art adaptive optics systems greatly improve image quality, their limited correction —due to finite bandwidth, mode number and seeing anisoplanat- ism— produces large residual values of SIC (Krishnappa & Feller 2012). Dual beam polarimeters are commonly used to reduce SIC between the intensity and polarization signals, however, they cannot compensate for the SIC introduced between circular and linear polarization, which can be relevant for high-precision polarimetry. It is known that fast modulation effectively reduces SIC, but the demodulation of the corresponding intensity signals imposes hard requirements on the frame rate of the associated cameras. One way to avoid a fast sensor, is to decouple the camera readout from the intensity demodulation step. This concept is the cornerstone of the very successful Zurich Imaging Polarimeter (ZIMPOL). Even though the ZIMPOL solution allows the detection of very faint signals (˜10-5), its design is not suitable for high-spatial-resolution applications. We are developing a polarimeter that focuses on both spatial resolution (package is similar to the SOLIS (Keller et al. 2003) design and optimized to have an achromatic total polarimetric efficiency above 80 % in the 400-700 nm wavelength

  16. Fast Solar Polarimeter: Prototype Characterization and First Results

    Science.gov (United States)

    Iglesias, F. A.; Feller, A.; Krishnappa, N.; Solanki, S. K.

    2016-04-01

    Due to the differential and non-simultaneous nature of polarization measurements, seeing induced crosstalk (SIC) and seeing limited spatial resolution can easily counterbalance the benefits of solar imaging polarimetry from the ground. The development of instrumental techniques to treat these issues is necessary to fully exploit the next generation of large-aperture solar facilities, and maintain ground-based data at a competitive level with respect to its space-based counterpart. In particular, considering that many open questions in modern solar physics demand data with challenging specifications of resolution and polarimetric sensitivity that can only be achieved with large telescope apertures (Stenflo 1999). Even if state-of-the-art adaptive optics systems greatly improve image quality, their limited correction —due to finite bandwidth, mode number and seeing anisoplanat- ism— produces large residual values of SIC (Krishnappa & Feller 2012). Dual beam polarimeters are commonly used to reduce SIC between the intensity and polarization signals, however, they cannot compensate for the SIC introduced between circular and linear polarization, which can be relevant for high-precision polarimetry. It is known that fast modulation effectively reduces SIC, but the demodulation of the corresponding intensity signals imposes hard requirements on the frame rate of the associated cameras. One way to avoid a fast sensor, is to decouple the camera readout from the intensity demodulation step. This concept is the cornerstone of the very successful Zurich Imaging Polarimeter (ZIMPOL). Even though the ZIMPOL solution allows the detection of very faint signals (˜10-5), its design is not suitable for high-spatial-resolution applications. We are developing a polarimeter that focuses on both spatial resolution (95%), have the double benefit of reducing seeing induced artifacts and improving the final spatial resolution by providing an optimal regime for the application of post

  17. Astronomical Video Suites

    Science.gov (United States)

    Francisco Salgado, Jose

    2010-01-01

    Astronomer and visual artist Jose Francisco Salgado has directed two astronomical video suites to accompany live performances of classical music works. The suites feature awe-inspiring images, historical illustrations, and visualizations produced by NASA, ESA, and the Adler Planetarium. By the end of 2009, his video suites Gustav Holst's The Planets and Astronomical Pictures at an Exhibition will have been presented more than 40 times in over 10 countries. Lately Salgado, an avid photographer, has been experimenting with high dynamic range imaging, time-lapse, infrared, and fisheye photography, as well as with stereoscopic photography and video to enhance his multimedia works.

  18. Multilayer-based soft X-ray polarimeter at the Beijing Synchrotron Radiation Facility

    Institute of Scientific and Technical Information of China (English)

    SUN Li-Juan; CUI Ming-Qi; ZHU Jie; ZHAO Yi-Dong; ZHENG Lei; WANG Zhan-Shan; ZHU Jing-Tao

    2013-01-01

    A compact high precision eight-axis automatism and two-axis manual soft-ray polarimeter with a multilayer has been designed,constructed,and installed in 3WlB at the Beijing Synchrotron Radiation Facility (BSRF).Four operational modes in the same device,which are double-reflection,double-transmission,front-reflection-behindtransmission and front-transmission-behind-reflection,have been realized.It can be used for the polarization analysis of synchrotron radiation.It also can be used to characterize the polarization properties of the optical elements in the soft X-ray energy range.Some experiments with Mo/Si and Cr/C multilayers have been performed by using this polarimeter with good results obtained.

  19. Optical design of Wolter-Ⅰ X-ray astronomical telescope%Wolter-Ⅰ型X射线天文望远镜的光学设计

    Institute of Scientific and Technical Information of China (English)

    刘宏颖; 穆宝忠; 王占山

    2012-01-01

    针对国内硬X射线天文观测的需求,研究了1~30 keV能段圆锥嵌套Wolter-Ⅰ型X射线天文望远镜的光学设计,推导了嵌套层之间的结构递推关系,给出了合理的望远镜初始结构.在最内层和最外层之间,设计了6组w/B4C宽带非周期多层膜,模拟得到系统的有效集光面积和分辨力.理论有效集光面积达到127 cm2(在2 keV处)和71 cm2(在30 keV处),系统角分辨力约10″.系统实际成像质量还受到公差的影响,引起像质下降的公差主要有辐条位置公差、镜面位置公差和镜面面形公差.目前演示实验方便改善的公差是辐条位置公差,给出了此公差的计算方法并对系统进行光线追迹,得到了成像点列图和分辨力改变情况.辐条位置公差从±15 μm缩小到±3 μm后,系统分辨力由1 ′提高到13″.%Optical design of nested conical Wolter-I X-ray telescope covering energy band from 1 to 30 keV was investigated. Recurrence relation of the nested structure was deduced. Depending on the needs for hard X-ray astronomical observations in China, the initial structure was presented, for which six groups of W/B4C aperiodic multilayers were designed between the innermost and the outermost shell of mirror. The simulation results showed that the effective area could achieve 127 cm2 (at 2 keV) and 71 cm2 (at 30 keV), and the resolution was estimated to be ~10" in half-power diameter. The actual image quality is also affected by tolerance. The main tolerances lowering image quality are position error, figure error and off-roundness. Tolerance to be improved most easily in the lab is off-roundness caused by bar. The spot diagram distribution and resolution was given after calculating off-roundness and ray tracing. When the bar position tolerance was changed from±15 μm to±3 μm, the responding resolution was improved from 1 to 13 .

  20. Sixteenth Century Astronomical Telescopy

    Science.gov (United States)

    Usher, P. D.

    2001-12-01

    Ophelia in Shakespeare's Hamlet is named for the ``moist star" which in mythology is the partner of Hamlet's royal Sun. Together the couple seem destined to rule on earth just as their celestial counterparts rule the heavens, but the tragedy is that they are afflicted, just as the Sun and Moon are blemished. In 1.3 Laertes lectures Ophelia on love and chastity, describing first Cytherean phases (crescent to gibbous) and then Lunar craters. Spots mar the Sun (1.1, 3.1). Also reported are Jupiter's Red Spot (3.4) and the resolution of the Milky Way into stars (2.2). These interpretations are well-founded and support the cosmic allegory. Observations must have been made with optical aid, probably the perspective glass of Leonard Digges, father of Thomas Digges. Notably absent from Hamlet is mention of the Galilean moons, owing perhaps to the narrow field-of-view of the telescope. That discovery is later celebrated in Cymbeline, published soon after Galileo's Siderius Nuncius in 1610. In 5.4 of Cymbeline the four ghosts dance ``in imitation of planetary motions" and at Jupiter's behest place a book on the chest of Posthumus Leonatus. His name identifies the Digges father and son as the source of data in Hamlet since Jupiter's moons were discovered after the deaths of Leonard (``leon+hart") and Thomas (the ``lion's whelp"). Lines in 5.4 urge us not to read more into the book than is contained between its covers; this is understandable because Hamlet had already reported the other data in support of heliocentricism and the cosmic model discussed and depicted by Thomas Digges in 1576. I conclude therefore that astronomical telescopy began in England before the last quarter of the sixteenth century.

  1. Observatory Sponsoring Astronomical Image Contest

    Science.gov (United States)

    2005-05-01

    Forget the headphones you saw in the Warner Brothers thriller Contact, as well as the guttural throbs emanating from loudspeakers at the Very Large Array in that 1997 movie. In real life, radio telescopes aren't used for "listening" to anything - just like visible-light telescopes, they are used primarily to make images of astronomical objects. Now, the National Radio Astronomy Observatory (NRAO) wants to encourage astronomers to use radio-telescope data to make truly compelling images, and is offering cash prizes to winners of a new image contest. Radio Galaxy Fornax A Radio Galaxy Fornax A Radio-optical composite image of giant elliptical galaxy NGC 1316, showing the galaxy (center), a smaller companion galaxy being cannibalized by NGC 1316, and the resulting "lobes" (orange) of radio emission caused by jets of particles spewed from the core of the giant galaxy Click on image for more detail and images CREDIT: Fomalont et al., NRAO/AUI/NSF "Astronomy is a very visual science, and our radio telescopes are capable of producing excellent images. We're sponsoring this contest to encourage astronomers to make the extra effort to turn good images into truly spectacular ones," said NRAO Director Fred K.Y. Lo. The contest, offering a grand prize of $1,000, was announced at the American Astronomical Society's meeting in Minneapolis, Minnesota. The image contest is part of a broader NRAO effort to make radio astronomical data and images easily accessible and widely available to scientists, students, teachers, the general public, news media and science-education professionals. That effort includes an expanded image gallery on the observatory's Web site. "We're not only adding new radio-astronomy images to our online gallery, but we're also improving the organization and accessibility of the images," said Mark Adams, head of education and public outreach (EPO) at NRAO. "Our long-term goal is to make the NRAO Image Gallery an international resource for radio astronomy imagery

  2. Astrophotonics: a new era for astronomical instruments

    CERN Document Server

    Bland-Hawthorn, J

    2009-01-01

    Astrophotonics lies at the interface of astronomy and photonics. This burgeoning field -- now formally recognized by the optics community -- has emerged over the past decade in response to the increasing demands of astronomical instrumentation. Early successes include: (i) planar waveguides to combine signals from widely spaced telescopes in stellar interferometry; (ii) frequency combs for ultra-high precision spectroscopy to detect planets around nearby stars; (iii) ultra-broadband fibre Bragg gratings to suppress unwanted background; (iv) photonic lanterns that allow single-mode behaviour within a multimode fibre; (v) planar waveguides to miniaturize astronomical spectrographs; (vi) large mode area fibres to generate artificial stars in the upper atmosphere for adaptive optics correction; (vii) liquid crystal polymers in optical vortex coronographs and adaptive optics systems. Astrophotonics, a field that has already created new photonic capabilities, is now extending its reach down to the Rayleigh scatteri...

  3. B-Machine Polarimeter: A Telescope to Measure the Polarization of the Cosmic Microwave Background

    CERN Document Server

    Williams, Brian D

    2013-01-01

    The B-Machine Telescope is the culmination of several years of development, construction, characterization and observation. The telescope is a departure from standard polarization chopping of correlation receivers to a half wave plate technique. Typical polarimeters use a correlation receiver to chop the polarization signal to overcome the $1/f$ noise inherent in HEMT amplifiers. B-Machine uses a room temperature half wave plate technology to chop between polarization states and measure the polarization signature of the CMB. The telescope has a demodulated $1/f$ knee of 5 mHz and an average sensitivity of 1.6 $\\mathrm{mK}\\sqrt{\\mathrm{s}}$. This document examines the construction, characterization, observation of astronomical sources, and data set analysis of B-Machine. Preliminary power spectra and sky maps with large sky coverage for the first year data set are included.

  4. B-machine polarimeter: A telescope to measure the polarization of the cosmic microwave background

    Science.gov (United States)

    Williams, Brian Dean

    The B-Machine Telescope is the culmination of several years of development, construction, characterization and observation. The telescope is a departure from standard polarization chopping of correlation receivers to a half wave plate technique. Typical polarimeters use a correlation receiver to chop the polarization signal to overcome the 1/f noise inherent in HEMT amplifiers. B-Machine uses a room temperature half wave plate technology to chop between polarization states and measure the polarization signature of the CMB. The telescope has a demodulated 1/f knee of 5 mHz and an average sensitivity of 1.6 mK s . This document examines the construction, characterization, observation of astronomical sources, and data set analysis of B-Machine. Preliminary power spectra and sky maps with large sky coverage for the first year data set are included.

  5. The innermost astronomical unit of protoplanetary disks

    CERN Document Server

    Kluska, J; Benisty, M

    2016-01-01

    Circumstellar disks around young stars are the birthsites of planets. It is thus fundamental to study the disks in which they form, their structure and the physical conditions therein. The first astronomical unit is of great interest because this is where the terrestrial-planets form and the angular momentum is controled via massloss through winds/jets. With its milli-arcsecond resolution, optical interferometry is the only technic able to spatially resolve the first few astronomical units of the disk. In this review, we will present a broad overview of studies of young stellar objects with interferometry, and discuss prospects for the future.

  6. Alternative Astronomical FITS imaging

    CERN Document Server

    Varsaki, Eleni E; Fotopoulos, Vassilis; Skodras, Athanassios N

    2012-01-01

    Astronomical radio maps are presented mainly in FITS format. Astronomical Image Processing Software (AIPS) uses a set of tables attached to the output map to include all sorts of information concerning the production of the image. However this information together with information on the flux and noise of the map is lost as soon as the image of the radio source in fits or other format is extracted from AIPS. This information would have been valuable to another astronomer who just uses NED, for example, to download the map. In the current work, we show a method of data hiding inside the radio map, which can be preserved under transformations, even for example while the format of the map is changed from fits to other lossless available image formats.

  7. Atlas of Astronomical Discoveries

    CERN Document Server

    Schilling, Govert

    2011-01-01

    Four hundred years ago in Middelburg, in the Netherlands, the telescope was invented. The invention unleashed a revolution in the exploration of the universe. Galileo Galilei discovered mountains on the Moon, spots on the Sun, and moons around Jupiter. Christiaan Huygens saw details on Mars and rings around Saturn. William Herschel discovered a new planet and mapped binary stars and nebulae. Other astronomers determined the distances to stars, unraveled the structure of the Milky Way, and discovered the expansion of the universe. And, as telescopes became bigger and more powerful, astronomers delved deeper into the mysteries of the cosmos. In his Atlas of Astronomical Discoveries, astronomy journalist Govert Schilling tells the story of 400 years of telescopic astronomy. He looks at the 100 most important discoveries since the invention of the telescope. In his direct and accessible style, the author takes his readers on an exciting journey encompassing the highlights of four centuries of astronomy. Spectacul...

  8. Astrobiology: An Astronomer's Perspective

    OpenAIRE

    Bergin, Edwin A.

    2013-01-01

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track th...

  9. Calibration of the Liverpool Telescope RINGO3 polarimeter

    CERN Document Server

    Słowikowska, Aga; Żejmo, Michał; Reig, Pablo; Steele, Iain

    2016-01-01

    We present an analysis of polarimetric observations of standard stars performed over the period of more than three years with the RINGO3 polarimeter mounted on the Liverpool Telescope. The main objective was to determine the instrumental polarisation of the RINGO3 polarimeter in three spectral energy ranges: blue (350--640~nm), green (650--760~nm) and red (770--1000~nm). The observations were conducted between 2012 and 2016. The total time span of 1126 days was split into five epochs due to the hardware changes to the observing system. Our results should be applied to calibrate all polarimetric observations performed with the RINGO3 polarimeter.

  10. A hard X-ray polarimeter utilizing Compton scattering

    Science.gov (United States)

    Sakurai, H.; Noma, M.; Niizeki, H.

    1991-01-01

    The paper describes a 50-cm-diam prototype of a novel Compton-scattering-type polarimeter for hard X-rays in the energy range 30-100 keV. The characteristics of the prototype polarimeter were investigated for various conditions. It was found that, with polarized X-rays from a simple polarizer, the detection efficiency and the modulation factor of the polarimeter with a 40-mm thick scatterer were 3.2 percent and 0.57 percent, respectively, at about 60 keV.

  11. Gamma-Ray Imager Polarimeter for Solar Flares Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose here to develop the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS), the next-generation instrument for high-energy solar observations. GRIPS will...

  12. A Pair Polarimeter for High Energy Photons

    Science.gov (United States)

    Tedeschi, David; Wojtsekhowski, B.; Abbott, D.; Vlahovic, B.; Hotta, T.; Kohri, H.; Matsumura, T.; Mibe, T.; Nakano, T.; Yurita, T.; Zegers, R.; Khandaker, M.; Feldman, G.; O'Rielly, G. V.; Wood, M.; Asai, G.; Rudge, A.; Weilhammer, P.

    2001-10-01

    The physics program at the Thomas Jefferson National Accelerator Facility includes fundamental experiments with polarized photon beams in the GeV energy range. To measure the degree of photon polarization, a photon polarimeter based on the detection of e^+e^- pairs has been developed for use in Hall B and was recently tested at the LEPS facility at SPring-8 in Japan. The use of silicon micro-strip detectors allows for the first time the measurement of the angle correlation in electron-positron pair production by high energy photons incident on an amorphous converter. Theoretical calculations of the pair production process show an asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of photon energies. Experimental results from the measurement of the pair asymmetry using 2 GeV photons from the SPring-8 facility will be presented.

  13. Development of two color laser diagnostics for the ITER poloidal polarimeter.

    Science.gov (United States)

    Kawahata, K; Akiyama, T; Tanaka, K; Nakayama, K; Okajima, S

    2010-10-01

    Two color laser diagnostics using terahertz laser sources are under development for a high performance operation of the Large Helical Device and for future fusion devices such as ITER. So far, we have achieved high power laser oscillation lines simultaneously oscillating at 57.2 and 47.7 μm by using a twin optically pumped CH(3)OD laser, and confirmed the original function, compensation of mechanical vibration, of the two color laser interferometer. In this article, application of the two color laser diagnostics to the ITER poloidal polarimeter and recent hardware developments will be described.

  14. Development of two color laser diagnostics for the ITER poloidal polarimeter

    International Nuclear Information System (INIS)

    Two color laser diagnostics using terahertz laser sources are under development for a high performance operation of the Large Helical Device and for future fusion devices such as ITER. So far, we have achieved high power laser oscillation lines simultaneously oscillating at 57.2 and 47.7 μm by using a twin optically pumped CH3OD laser, and confirmed the original function, compensation of mechanical vibration, of the two color laser interferometer. In this article, application of the two color laser diagnostics to the ITER poloidal polarimeter and recent hardware developments will be described.

  15. POLOCAM: a millimeter wavelength cryogenic polarimeter prototype for MUSIC-POL

    Science.gov (United States)

    Laurent, Glenn T.; Vaillancourt, John E.; Savini, Giorgio; Ade, Peter A. R.; Beland, Stephane; Glenn, Jason; Hollister, Matthew I.; Maloney, Philip R.; Sayers, Jack

    2012-09-01

    As a proof-of-concept, we have constructed and tested a cryogenic polarimeter in the laboratory as a prototype for the MUSIC instrument (Multiwavelength Sub/millimeter Kinetic Inductance Camera). The POLOCAM instrument consists of a rotating cryogenic polarization modulator (sapphire half-waveplate) and polarization analyzer (lithographed copper polarizers deposited on a thin film) placed into the optical path at the Lyot stop (4K cold pupil stop) in a cryogenic dewar. We present an overview of the project, design and performance results of the POLOCAM instrument (including polarization efficiencies and instrumental polarization), as well as future application to the MUSIC-POL instrument.

  16. Development of a Hard X-ray focal plane Compton Polarimeter: A compact polarimetric configuration with Scintillators and Si photomultipliers

    OpenAIRE

    Chattopadhyay, T.; Vadawale, S. V.; Goyal, S K; S., Mithun N. P.; Patel, A. R.; Shukla, R.; Ladiya, T.; M Shanmugam; Patel, V R; Ubale, G. P.

    2015-01-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane ...

  17. Astronomers as Software Developers

    Science.gov (United States)

    Pildis, Rachel A.

    2016-01-01

    Astronomers know that their research requires writing, adapting, and documenting computer software. Furthermore, they often have to learn new computer languages and figure out how existing programs work without much documentation or guidance and with extreme time pressure. These are all skills that can lead to a software development job, but recruiters and employers probably won't know that. I will discuss all the highly useful experience that astronomers may not know that they already have, and how to explain that knowledge to others when looking for non-academic software positions. I will also talk about some of the pitfalls I have run into while interviewing for jobs and working as a developer, and encourage you to embrace the curiosity employers might have about your non-standard background.

  18. Astronomical Surveys and Big Data

    CERN Document Server

    Mickaelian, A M

    2015-01-01

    Recent all-sky and large-area astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum are reviewed, from Gamma-ray to radio, such as Fermi-GLAST and INTEGRAL in Gamma-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and II based catalogues (APM, MAPS, USNO, GSC) in optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio and many others, as well as most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS) and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). An overall understanding of the coverage along the whole wavelength range and comparisons between various surveys are given: galaxy redshift surveys, QSO/AGN, radio, Galactic structure, and Dark Energy surveys. Astronomy has entered the Big Data era. Astrophysical Virtual Observatories and Computational Astrophysics play a...

  19. Astronomical surveys and big data

    Science.gov (United States)

    Mickaelian, Areg M.

    Recent all-sky and large-area astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum, from γ -rays to radio waves, are reviewed, including such as Fermi-GLAST and INTEGRAL in γ -ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and POSS II-based catalogues (APM, MAPS, USNO, GSC) in the optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio range, and many others, as well as the most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS), and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). An overall understanding of the coverage along the whole wavelength range and comparisons between various surveys are given: galaxy redshift surveys, QSO/AGN, radio, Galactic structure, and Dark Energy surveys. Astronomy has entered the Big Data era, with Astrophysical Virtual Observatories and Computational Astrophysics playing an important role in using and analyzing big data for new discoveries.

  20. The Biographical Encyclopedia of Astronomers

    CERN Document Server

    Hockey, Thomas; Williams, Thomas R; Bracher, Katherine; Jarrell, Richard A; Marché, Jordan D; Ragep, F. Jamil; Palmeri, JoAnn; Bolt, Marvin

    2007-01-01

    The Biographical Encyclopedia of Astronomers is a unique and valuable resource for historians and astronomers alike. The two volumes include approximately 1550 biographical sketches on astronomers from antiquity to modern times. It is the collective work of about 400 authors edited by an editorial board of 9 historians and astronomers, and provides additional details on the nature of an entry and some summary statistics on the content of entries. This new reference provides biographical information on astronomers and cosmologists by utilizing contemporary historical scholarship. Individual entries vary from 100 to 1500 words, including the likes of the superluminaries such as Newton and Einstein, as well as lesser-known astronomers like Galileo's acolyte, Mario Guiducci. A comprehensive contributor index helps researchers to identify the authors of important scientific topics and treatises.

  1. Destriping Cosmic Microwave Background Polarimeter data

    CERN Document Server

    Zonca, Andrea; Meinhold, Peter; Lubin, Philip

    2013-01-01

    Destriping is a well-established technique for removing low-frequency correlated noise from Cosmic Microwave Background (CMB) survey data. In this paper we present a destriping algorithm tailored to data from a polarimeter, i.e. an instrument where each channel independently measures the polarization of the input signal. We also describe a fully parallel implementation in Python released as Open Source software and analyze its results and performance on simulated datasets, both the design case of signal and correlated noise, and also with the addition of other systematic effects. Finally we apply the algorithm to 30 days of 40 GHz polarized microwave data gathered from the B-Machine experiment, developed at UCSB. The B-Machine data and destriped maps are publicly available. The purpose is the development of a scalable software tool to be applied to the upcoming 12 months of temperature and polarization data from LATTE (Low frequency All sky TemperaTure Experiment) at 8 GHz and to even larger datasets.

  2. Performance of the PRAXyS X-ray Polarimeter

    CERN Document Server

    Iwakiri, W B; Cole, R; Enoto, T; Hayato, A; Hill, J E; Jahoda, K; Kaaret, P; Kitaguchi, T; Kubota, M; Marlowe, H; McCurdy, R; Takeuchi, Y; Tamagawa, T

    2016-01-01

    The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2-10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

  3. Really Bad Astronomers

    Science.gov (United States)

    Hockey, Thomas A.

    2009-01-01

    What happens when even Percival Lowell stops believing in your Mars observations? History can be troubling. This I learned while editing the Biographical Encyclopedia of Astronomers (Springer, 2007). There have been astronomers who do not fit our commonly held, and clung to, conceptual model: a sociological system that sifts out generally like-minded and sensible colleagues. I refer to those individuals who (for at least a time) successfully entered the mainstream profession, but now disturb our worldview that says prosperity as a scientist usually is achieved by a rational being holding certain common values. My List of Shame includes examples from each of the last four centuries. Not "crack pot” cosmologists, these were hard-working observers for whom the end justified the means. And they all got away with it. Each person I discuss was vetted by the professional establishment of the day. Yet you will learn how to be fired from a major observatory, banned from prominent journals. But only after damage to the science is done. Be afraid.

  4. Grigor Narekatsi's astronomical insights

    Science.gov (United States)

    Poghosyan, Samvel

    2015-07-01

    What stand out in the solid system of Gr. Narekatsi's naturalistic views are his astronomical insights on the material nature of light, its high speed and the Sun being composed of "material air". Especially surprising and fascinating are his views on stars and their clusters. What astronomers, including great Armenian academician V. Ambartsumian (scattering of stellar associations), would understand and prove with much difficulty thousand years later, Narekatsi predicted in the 10th century: "Stars appear and disappear untimely", "You who gather and scatter the speechless constellations, like a flock of sheep". Gr. Narekatsti's reformative views were manifested in all the spheres of the 10th century social life; he is a reformer of church life, great language constructor, innovator in literature and music, freethinker in philosophy and science. His ideology is the reflection of the 10th century Armenian Renaissance. During the 9th-10th centuries, great masses of Armenians, forced to migrate to the Balkans, took with them and spread reformative ideas. The forefather of the western science, which originated in the period of Reformation, is considered to be the great philosopher Nicholas of Cusa. The study of Gr. Narekatsti's logic and naturalistic views enables us to claim that Gr. Narekatsti is the great grandfather of European science.

  5. Professional Ethics for Astronomers

    Science.gov (United States)

    Marvel, K. B.

    2005-05-01

    There is a growing recognition that professional ethics is an important topic for all professional scientists, especially physical scientists. Situations at the National Laboratories have dramatically proven this point. Professional ethics is usually only considered important for the health sciences and the legal and medical professions. However, certain aspects of the day to day work of professional astronomers can be impacted by ethical issues. Examples include refereeing scientific papers, serving on grant panels or telescope allocation committees, submitting grant proposals, providing proper references in publications, proposals or talks and even writing recommendation letters for job candidates or serving on search committees. This session will feature several speakers on a variety of topics and provide time for questions and answers from the audience. Confirmed speakers include: Kate Kirby, Director Institute for Theoretical Atomic and Molecular Physics - Professional Ethics in the Physical Sciences: An Overview Rob Kennicutt, Astrophysical Journal Editor - Ethical Issues for Publishing Astronomers Peggy Fischer, Office of the NSF Inspector General - Professional Ethics from the NSF Inspector General's Point of View

  6. MEASUREMENT OF LOW ENERGY DETECTION EFFICIENCY OF A PLASTIC SCINTILLATOR: IMPLICATIONS ON THE LOWER ENERGY LIMIT AND SENSITIVITY OF A HARD X-RAY FOCAL PLANE COMPTON POLARIMETER

    International Nuclear Information System (INIS)

    The polarization measurements in X-rays offer a unique opportunity for the study of physical processes under the extreme conditions prevalent at compact X-ray sources, including gravitation, magnetic field, and temperature. Unfortunately, there has been no real progress in observational X-ray polarimetry thus far. Although photoelectron tracking-based X-ray polarimeters provide realistic prospects of polarimetric observations, they are effective in the soft X-rays only. With the advent of hard X-ray optics, it has become possible to design sensitive X-ray polarimeters in hard X-rays based on Compton scattering. An important point that should be carefully considered for the Compton polarimeters is the lower energy threshold of the active scatterer, which typically consists of a plastic scintillator due to its lowest effective atomic number. Therefore, an accurate understanding of the plastic scintillators energy threshold is essential to make a realistic estimate of the energy range and sensitivity of any Compton polarimeter. In this context, we set up an experiment to investigate the plastic scintillators behavior for very low energy deposition events. The experiment involves the detection of Compton scattered photons from a long, thin, plastic scintillator (a similar configuration as the eventual Compton polarimeter) by a high resolution CdTe detector at different scattering angles. We find that it is possible to detect energy deposition well below 1 keV, though with decreasing efficiency. We present detailed semianalytical modeling of our experimental setup and discuss the results in the context of the energy range and sensitivity of the Compton polarimeter involving plastic scintillators

  7. Atomic and Molecular Aspects of Astronomical Spectra

    CERN Document Server

    Sochi, Taha

    2012-01-01

    In the first section we present the atomic part where a C2+ atomic target was prepared and used to generate theoretical data to investigate recombination lines arising from electron-ion collisions in thin plasma. R-matrix method was used to describe the C2+ plus electron system. Theoretical data concerning bound and autoionizing states were generated in the intermediate-coupling approximation. The data were used to generate dielectronic recombination data for C+ which include transition lines, oscillator strengths, radiative transition probabilities, emissivities and dielectronic recombination coefficients. The data were cast in a line list containing 6187 optically-allowed transitions which include many C II lines observed in astronomical spectra. This line list was used to analyze the spectra from a number of astronomical objects, mainly planetary nebulae, and identify their electron temperature. The electron temperature investigation was also extended to include free electron energy analysis to investigate...

  8. Proton Polarimeter Calibration between 82 and 217 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Glister, J; Lee, B; Beck, A; Brash, E; Camsonne, A; Choi, S; Dumas, J; Feuerbach, R; Gilman, R; Higinbotham, D W; Jiang, X; Jones, M K; May-Tal Beck, S; McCullough, E; Paolone, M; Piasetzky, E; Roche, J; Rousseau, Y; Sarty, A J; Sawatzky, B; Strauch, S

    2009-07-01

    The proton analyzing power in carbon has been measured for energies of 82 to 217 MeV and proton scattering angles of 5 to 41 degrees. The measurements were carried out using polarized protons from the elastic scattering H(pol. e, pol. p) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies.

  9. A Compton polarimeter for Parametric X-radiation

    CERN Document Server

    They, J; Kotthaus, R; Pugachev, D

    2001-01-01

    A compact 90 deg.-Compton scatter polarimeter has been developed to be used for energy resolved linear polarization analysis of Parametric X-radiation (PXR) in the energy range below 10 keV. The polarimeter employs thermoelectrically cooled silicon drift detectors. The polarization sensitivity and instrumental asymmetries of the polarimeter have been studied with synchrotron radiation at energies from 6 to 11 keV. The analyzing power is close to unity in agreement with expectations and Monte Carlo simulation results. Instrumental asymmetries of a few percent have been measured and corrected with residual statistical uncertainties of O (10 sup - sup 3). The orientation of the polarization plane is determined to be within 4 m.

  10. Astronomical tides and earthquakes

    Science.gov (United States)

    Wu, Xiaoping; Mao, Wei; Huang, Yong

    2001-03-01

    A review on the studies of correlation between astronomical tides and earthquakes is given in three categories, including (1) earthquakes and the relative locations of the sun, the moon and the earth, (2) earthquakes and the periods and phases of tides and (3) earthquakes and the tidal stress. The first two categories mainly investigate whether or not there exist any dominant pattern of the relative locations of the sun, the moon and the earth during earthquakes, whether or not the occurrences of earthquakes are clustered in any special phase during a tidal period, whether or not there exists any tidal periodic phenomenon in seismic activities, By empasizing the tidal stress in seismic focus, the third category investigates the relationship between various seismic faults and the triggering effects of tidal stress, which reaches the crux of the issue. Possible reasons to various inconsistent investigation results by using various methods and samples are analyzed and further investigations are proposed.

  11. The SIMBAD astronomical database

    CERN Document Server

    Wenger, M; Egret, D; Dubois, P; Bonnarel, F; Borde, S; Genova, F; Jasniewicz, G; Laloe, S; Lesteven, S; Monier, R; Wenger, Marc; Ochsenbein, Francois; Egret, Daniel; Dubois, Pascal; Bonnarel, Francois; Borde, Suzanne; Genova, Francoise; Jasniewicz, Gerard; Laloe, Suzanne; Lesteven, Soizick; Monier, Richard

    2000-01-01

    Simbad is the reference database for identification and bibliography ofastronomical objects. It contains identifications, `basic data', bibliography,and selected observational measurements for several million astronomicalobjects. Simbad is developed and maintained by CDS, Strasbourg. Building thedatabase contents is achieved with the help of several contributing institutes.Scanning the bibliography is the result of the collaboration of CDS withbibliographers in Observatoire de Paris (DASGAL), Institut d'Astrophysique deParis, and Observatoire de Bordeaux. When selecting catalogues and tables forinclusion, priority is given to optimal multi-wavelength coverage of thedatabase, and to support of research developments linked to large projects. Inparallel, the systematic scanning of the bibliography reflects the diversityand general trends of astronomical research. A WWW interface to Simbad is available at: http://simbad.u-strasbg.fr/Simbad

  12. Run-09 pC polarimeter analysis

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, I.; Aschenauer, E.; Atoyan, G.; Bazilevsky, A.; Gill, R.; Huang, H.; Lee, S.; Li, X.; Makdisi, Y.; Morozov, B.; Nakagawa, I.; Svirida, D.; Zelenski, A.

    2010-08-01

    Analysis of PC polarimeter data at {radical}s = 200 and 500 GeV from Run9 is presented. Final polarization results, fill-by-fill, for blue and yellow beams, as to be used by RHIC experiments (in collisions) are released and collected in http://www4.rcf.bnl.gov/cnipol/pubdocs/Run09Offline/. Global relative systematic uncertainties {delta}P/P (to be considered as correlated from fill to fill) are 4.7% for 100 GeV beams, and 8.3% (12.1%) for blue (yellow) 250 GeV beams. For a product of two beam polarizations P{sub B} {center_dot} P{sub Y} (used in double spin asymmetry measurements) the relative uncertainty {delta}(P{sub B} {center_dot} P{sub Y})/(P{sub B} {center_dot} P{sub Y}) 8.8% for 100 GeV beams and 18.5% for 250 GeV beams. For the average between two beam polarization (P{sub B} + P{sub Y})/2 (used in single spin asymmetry measurements, when data from two polarized beams are combined) the relative uncertainty is 4.4% for 100 GeV beams and 9.2% for 250 GeV beams. Larger uncertainties for 250 GeV beams relate to significant rate related systematic effects experienced in the first part of Run9 (due to thicker targets used and smaller trans. beam size at higher beam energy).

  13. DESIGN AND MEASUREMENT OF THE STOKES POLARIMETER FOR THE COSMO K-CORONAGRAPH

    International Nuclear Information System (INIS)

    We present the Stokes polarimeter for the new Coronal Solar Magnetism Observatory K-coronagraph. The polarimeter can be used in two modes. In observation mode, it is sensitive to linear polarization only and operates as a ''Stokes definition'' polarimeter. In the ideal case, such a modulator isolates a particular Stokes parameter in each modulation state. For calibrations, the polarimeter can diagnose the full Stokes vector. We present here the design process of the polarimeter, analyze its tolerances with a Monte Carlo method, develop a way to align the individual elements, and measure and evaluate its performance in both modes

  14. Two-dimensional solar spectropolarimetry with the KIS/IAA Visible Imaging Polarimeter

    CERN Document Server

    Beck, C; Kentischer, T J; Tritschler, A; Iniesta, J C del Toro

    2010-01-01

    Spectropolarimetry at high spatial and spectral resolution is a basic tool to characterize the magnetic properties of the solar atmosphere. We introduce the KIS/IAA Visible Imaging Polarimeter (VIP), a new post-focus instrument that upgrades the TESOS spectrometer at the German VTT into a full vector polarimeter. VIP is a collaboration between the KIS and the IAA. We describe the optical setup of VIP, the data acquisition procedure, and the calibration of the spectropolarimetric measurements. We show examples of data taken between 2005 and 2008 to illustrate the potential of the instrument. VIP is capable of measuring the four Stokes profiles of spectral lines in the range from 420 to 700 nm with a spatial resolution better than 0.5". Lines can be sampled at 40 wavelength positions in 60 s, achieving a noise level of about 2 x 10E-3 with exposure times of 300 ms and pixel sizes of 0.17" x 0.17" (2 x 2 binning). The polarization modulation is stable over periods of a few days, ensuring high polarimetric accura...

  15. Polarisation at HERA. Reanalysis of the HERA II polarimeter data

    Energy Technology Data Exchange (ETDEWEB)

    Sobloher, B.; Behnke, T.; Olsson, J.; Pitzl, D.; Schmitt, S.; Tomaszewska, J.; Fabbri, R.

    2012-01-15

    In this technical note we briefly present the analysis of the HERA polarimeters (transversal and longitudinal) as of summer 2011. We present the final reanalysis of the TPOL data, and discuss the systematic uncertainties. A procedure to combine and average LPOL and TPOL data is presented. (orig.)

  16. Far infrared polarimeter with very low instrumental polarization

    CERN Document Server

    Battistelli, E S; Lamagna, L; Maoli, R; Melchiorri, F; Palladino, E; Savini, G; Mauskopf, P D; Orlando, A E

    2002-01-01

    After a short analysis of the main problems involved in the construction of a Far Infrared polarimeter with very low instrumental noise, we describe the instrument that will be employed at MITO telescope to search for calibration sources and investigate polarization near the CMB anisotropy peaks in the next campaign (Winter 2002-03).

  17. Algorithms for classification of astronomical object spectra

    Science.gov (United States)

    Wasiewicz, P.; Szuppe, J.; Hryniewicz, K.

    2015-09-01

    Obtaining interesting celestial objects from tens of thousands or even millions of recorded optical-ultraviolet spectra depends not only on the data quality but also on the accuracy of spectra decomposition. Additionally rapidly growing data volumes demands higher computing power and/or more efficient algorithms implementations. In this paper we speed up the process of substracting iron transitions and fitting Gaussian functions to emission peaks utilising C++ and OpenCL methods together with the NOSQL database. In this paper we implemented typical astronomical methods of detecting peaks in comparison to our previous hybrid methods implemented with CUDA.

  18. UNI Astronomical Observatory - OAUNI: First light

    CERN Document Server

    Pereyra, Antonio; Meza, Erick; Cori, William; Ricra, José; Zevallos, Maria Isela

    2015-01-01

    We show the actual status of the project to implement the Astronomical Observatory of the National University of Engineering (OAUNI), including its first light. The OAUNI was installed with success at the site of the Huancayo Observatory on the peruvian central Andes. At this time, we are finishing the commissioning phase which includes the testing of all the instruments: optical tube, robotic mount, CCD camera, filter wheel, remote access system, etc. The first light gathered from a stellar field was very promissory. The next step will be to start the scientific programs and to bring support to the undergraduate courses in observational astronomy at the Faculty of Sciences of UNI.

  19. XEphem: Interactive Astronomical Ephemeris

    Science.gov (United States)

    Downey, Elwood Charles

    2011-12-01

    XEphem is a scientific-grade interactive astronomical ephemeris package for UNIX-like systems. Written in C, X11 and Motif, it is easily ported to systems. Among other things, XEphem: computes heliocentric, geocentric and topocentric information for all objects; has built-in support for all planets; the moons of Mars, Jupiter, Saturn, Uranus and Earth; central meridian longitude of Mars and Jupiter; Saturn's rings; and Jupiter's Great Red Spot; allows user-defined objects including stars, deepsky objects, asteroids, comets and Earth satellites; provides special efficient handling of large catalogs including Tycho, Hipparcos, GSC; displays data in configurable tabular formats in conjunction with several interactive graphical views; displays a night-at-a-glance 24 hour graphic showing when any selected objects are up; displays 3-D stereo Solar System views that are particularly well suited for visualizing comet trajectories; quickly finds all close pairs of objects in the sky; and sorts and prints all catalogs with very flexible criteria for creating custom observing lists. Its capabilities are listed more fully in the user manual introduction.

  20. Astronomical Observing Conditions at Xinglong Observatory from 2007 to 2014

    CERN Document Server

    Zhang, Ji-Cheng; Lu, Xiao-Meng; Cao, Zi-Huang; Chen, Xu; Mao, Yong-Na; Jiang, Xiao-Jun

    2016-01-01

    Xinglong Observatory of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC), is one of the major optical observatories in China, which hosts nine optical telescopes including the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the 2.16 m reflector. Scientific research from these telescopes is focused on stars, galaxies, and exoplanets using multicolor photometry and spectroscopic observations. Therefore, it is important to provide the observing conditions of the site, in detail, to the astronomers for an efficient use of these facilities. In this article, we present the characterization of observing conditions at Xinglong Observatory based on the monitoring of meteorology, seeing and sky brightness during the period from 2007 to 2014. Results suggest that Xinglong Observatory is still a good site for astronomical observations. Our analysis of the observing conditions at Xinglong Observatory can be used as a reference to the observers on targets selection, observi...

  1. Development of real-time rotating waveplate Stokes polarimeter using multi-order retardation for ITER poloidal polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Imazawa, R., E-mail: imazawa.ryota@jaea.go.jp; Kawano, Y.; Ono, T.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki (Japan)

    2016-01-15

    The rotating waveplate Stokes polarimeter was developed for ITER (International Thermonuclear Experimental Reactor) poloidal polarimeter. The generalized model of the rotating waveplate Stokes polarimeter and the algorithm suitable for real-time field-programmable gate array (FPGA) processing were proposed. Since the generalized model takes into account each component associated with the rotation of the waveplate, the Stokes parameters can be accurately measured even in unideal condition such as non-uniformity of the waveplate retardation. Experiments using a He-Ne laser showed that the maximum error and the precision of the Stokes parameter were 3.5% and 1.2%, respectively. The rotation speed of waveplate was 20 000 rpm and time resolution of measuring the Stokes parameter was 3.3 ms. Software emulation showed that the real-time measurement of the Stokes parameter with time resolution of less than 10 ms is possible by using several FPGA boards. Evaluation of measurement capability using a far-infrared laser which ITER poloidal polarimeter will use concluded that measurement error will be reduced by a factor of nine.

  2. Development of real-time rotating waveplate Stokes polarimeter using multi-order retardation for ITER poloidal polarimeter.

    Science.gov (United States)

    Imazawa, R; Kawano, Y; Ono, T; Itami, K

    2016-01-01

    The rotating waveplate Stokes polarimeter was developed for ITER (International Thermonuclear Experimental Reactor) poloidal polarimeter. The generalized model of the rotating waveplate Stokes polarimeter and the algorithm suitable for real-time field-programmable gate array (FPGA) processing were proposed. Since the generalized model takes into account each component associated with the rotation of the waveplate, the Stokes parameters can be accurately measured even in unideal condition such as non-uniformity of the waveplate retardation. Experiments using a He-Ne laser showed that the maximum error and the precision of the Stokes parameter were 3.5% and 1.2%, respectively. The rotation speed of waveplate was 20 000 rpm and time resolution of measuring the Stokes parameter was 3.3 ms. Software emulation showed that the real-time measurement of the Stokes parameter with time resolution of less than 10 ms is possible by using several FPGA boards. Evaluation of measurement capability using a far-infrared laser which ITER poloidal polarimeter will use concluded that measurement error will be reduced by a factor of nine.

  3. Islamic Astronomical Instruments and Observatories

    Science.gov (United States)

    Heidarzadeh, Tofigh

    This chapter is a brief survey of astronomical instruments being used and developed in Islamic territories from the eighth to the fifteenth centuries as well as a concise account of major observatories and observational programs in this period.

  4. A Millimeter-Wave Galactic Plane Survey With The BICEP Polarimeter

    CERN Document Server

    Bierman, E M; Dowell, C D; Keating, B G; Ade, P; Barkats, D; Barron, D; Battle, J O; Bock, J J; Chiang, H C; Culverhouse, T L; Duband, L; Hivon, E F; Holzapfel, W L; Hristov, V V; Kaufman, J P; Kovac, J M; Kuo, C L; Lange, A E; Leitch, E M; Mason, P V; Miller, N J; Nguyen, H T; Pryke, C; Richter, S; Rocha, G M; Sheehy, C; Takahashi, Y D; Yoon, K W

    2011-01-01

    In addition to its potential to probe the Inflationary cosmological paradigm, millimeter-wave polarimetry is a powerful tool for studying the Milky Way galaxy's composition and magnetic field structure. Towards this end, presented here are Stokes I, Q, and U maps of the Galactic plane from the millimeter-wave polarimeter BICEP covering the Galactic longitude range 260 - 340 degrees in three atmospheric transmission windows centered on 100, 150, and 220 GHz. The maps sample an optical depth 1 < AV < 30, and are consistent with previous characterizations of the Galactic millimeter-wave frequency spectrum and the large-scale magnetic field structure permeating the interstellar medium. Polarized emission is detected over the entire region within two degrees of the Galactic plane and indicates that the large-scale magnetic field is oriented parallel to the plane of the Galaxy. An observed trend of decreasing polarization fraction with increasing total intensity rules out the simplest model of a constant Gala...

  5. Imaging polarimeter/interferometer arrays for tokamak measurements. Technical progress report FY 84

    International Nuclear Information System (INIS)

    The Task IIIB program has continued to make significant strides during the last year. Laboratory test studies continued in our development efforts on imaging polarimeter and interferometer arrays in support of the tokamak measurements carried out under Task IIIA. This work ensures that the system optics and resolution are completely understood prior to attempting actual tokamak measurements. New microbolometer designs and fabrication techniques increased their sensitivity by over an order of magnitude compared with the previous devices. In addition, the development of sensitive monolithic integrated Schottky diode detector arrays has shown rapid progress. Heterodyne noise temperature of less than 90000K have already been achieved at 94 GHz with extension into the submillimeter region anticipated during the coming year

  6. A comparison of co-temporal magnetograms obtained with the Huairou magnetograph and the Spectro-Polarimeter on board Hinode

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We have compared a set of co-temporal magnetograms obtained with the Solar Magnetic Field Tele-scope (SMFT) of the Huairou Solar Observing Station (HSOS) and with the Spectro-Polarimeter of the Solar Optical Telescope (SP/SOT) on board Hinode to check the linear calibrations of SMFT vector magnetograms. The comparison shows that the currently used calibration coefficients of the SMFT have under-estimated the flux density and that a center-to-limb variation of the calibration coefficients was not taken into account by previous calibrations.

  7. Compton polarimeter as a focal plane detector for hard X-ray telescope: sensitivity estimation with Geant4 simulations

    Science.gov (United States)

    Chattopadhyay, T.; Vadawale, S. V.; Pendharkar, J.

    2013-04-01

    X-ray polarimetry can be an important tool for investigating various physical processes as well as their geometries at the celestial X-ray sources. However, X-ray polarimetry has not progressed much compared to the spectroscopy, timing and imaging mainly due to the extremely photon-hungry nature of X-ray polarimetry leading to severely limited sensitivity of X-ray polarimeters. The great improvement in sensitivity in spectroscopy and imaging was possible due to focusing X-ray optics which is effective only at the soft X-ray energy range. Similar improvement in sensitivity of polarisation measurement at soft X-ray range is expected in near future with the advent of GEM based photoelectric polarimeters. However, at energies >10 keV, even spectroscopic and imaging sensitivities of X-ray detector are limited due to lack of focusing optics. Thus hard X-ray polarimetry so far has been largely unexplored area. On the other hand, typically the polarisation degree is expected to increase at higher energies as the radiation from non-thermal processes is dominant fraction. So polarisation measurement in hard X-ray can yield significant insights into such processes. With the recent availability of hard X-ray optics (e.g. with upcoming NuSTAR, Astro-H missions) which can focus X-rays from 5 KeV to 80 KeV, sensitivity of X-ray detectors in hard X-ray range is expected to improve significantly. In this context we explore feasibility of a focal plane hard X-ray polarimeter based on Compton scattering having a thin plastic scatterer surrounded by cylindrical array scintillator detectors. We have carried out detailed Geant4 simulation to estimate the modulation factor for 100 % polarized beam as well as polarimetric efficiency of this configuration. We have also validated these results with a semi-analytical approach. Here we present the initial results of polarisation sensitivities of such focal plane Compton polarimeter coupled with the reflection efficiency of present era hard X

  8. Astronomical Surveys, Catalogs, Databases, and Archives

    Science.gov (United States)

    Mickaelian, A. M.

    2016-06-01

    All-sky and large-area astronomical surveys and their cataloged data over the whole range of electromagnetic spectrum are reviewed, from γ-ray to radio, such as Fermi-GLAST and INTEGRAL in γ-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and II based catalogues (APM, MAPS, USNO, GSC) in optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio and many others, as well as most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS) and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). Most important astronomical databases and archives are reviewed as well, including Wide-Field Plate DataBase (WFPDB), ESO, HEASARC, IRSA and MAST archives, CDS SIMBAD, VizieR and Aladin, NED and HyperLEDA extragalactic databases, ADS and astro-ph services. They are powerful sources for many-sided efficient research using Virtual Observatory tools. Using and analysis of Big Data accumulated in astronomy lead to many new discoveries.

  9. Enthusiastic Little Astronomers

    Science.gov (United States)

    Novak, Ines

    2016-04-01

    Younger primary school students often show great interest in the vast Universe hiding behind the starry night's sky, but don't have a way of learning about it and exploring it in regular classes. Some of them would search children's books, Internet or encyclopedias for information or facts they are interested in, but there are those whose hunger for knowledge would go unfulfilled. Such students were the real initiators of our extracurricular activity called Little Astronomers. With great enthusiasm they would name everything that interests them about the Universe that we live in and I would provide the information in a fun and interactive yet acceptable way for their level of understanding. In our class we learn about Earth and its place in the Solar System, we learn about the planets and other objects of our Solar System and about the Sun itself. We also explore the night sky using programs such as Stellarium, learning to recognize constellations and name them. Most of our activities are done using a PowerPoint presentation, YouTube videos, and Internet simulations followed by some practical work the students do themselves. Because of the lack of available materials and funds, most of materials are hand made by the teacher leading the class. We also use the school's galileoscope as often as possible. Every year the students are given the opportunity to go to an observatory in a town 90 km away so that they could gaze at the sky through the real telescope for the first time. Our goal is to start stepping into the world of astronomy by exploring the secrets of the Universe and understanding the process of rotation and revolution of our planet and its effects on our everyday lives and also to become more aware of our own role in our part of the Universe. The hunger for knowledge and enthusiasm these students have is contagious. They are becoming more aware of their surroundings and also understanding their place in the Universe that helps them remain humble and helps

  10. The New Amateur Astronomer

    Science.gov (United States)

    Mobberley, Martin

    Amateur astronomy has changed beyond recognition in less than two decades. The reason is, of course, technology. Affordable high-quality telescopes, computer-controlled 'go to' mountings, autoguiders, CCD cameras, video, and (as always) computers and the Internet, are just a few of the advances that have revolutionized astronomy for the twenty-first century. Martin Mobberley first looks at the basics before going into an in-depth study of what’s available commercially. He then moves on to the revolutionary possibilities that are open to amateurs, from imaging, through spectroscopy and photometry, to patrolling for near-earth objects - the search for comets and asteroids that may come close to, or even hit, the earth. The New Amateur Astronomer is a road map of the new astronomy, equally suitable for newcomers who want an introduction, or old hands who need to keep abreast of innovations. From the reviews: "This is one of several dozen books in Patrick Moore's "Practical Astronomy" series. Amid this large family, Mobberley finds his niche: the beginning high-tech amateur. The book's first half discusses equipment: computer-driven telescopes, CCD cameras, imaging processing software, etc. This market is changing every bit as rapidly as the computer world, so these details will be current for only a year or two. The rest of the book offers an overview of scientific projects that serious amateurs are carrying out these days. Throughout, basic formulas and technical terms are provided as needed, without formal derivations. An appendix with useful references and Web sites is also included. Readers will need more than this book if they are considering a plunge into high-tech amateur astronomy, but it certainly will whet their appetites. Mobberley's most valuable advice will save the book's owner many times its cover price: buy a quality telescope from a reputable dealer and install it in a simple shelter so it can be used with as little set-up time as possible. A poor

  11. Experimental study on helium optical electron polarimetry

    Institute of Scientific and Technical Information of China (English)

    Ding Hai-Bing; Pang Wen-Ning; Liu Yi-Bao; Shang Ren-Cheng

    2005-01-01

    Optical electron polarimetry is suitable for calibration of a spin-polarized electron source, especially for measurement of polarization of spin-polarized electron beam. In this paper, a new optical electron polarimeter is described,which is based on the circularly polarized He radiation induced by the bombarding of He atoms with spin-polarized electrons. The theoretical basis of the optical electron polarimetry and the structure of the optical electron polarimeter are discussed. The measurement of polarization of spin-polarized electrons produced from a new GaAs (100) spin-polarized electron source is carried out. The result of polarization of 30.8% for our spin-polarized electron source is obtained using the He optical electron polarimeter.

  12. Operation experience of p-Carbon polarimeter in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Alekseev, I. G. [Inst. of Theoretical and Experimental Physics (ITEP), Moscow (Russian Federation); Aschenauer, E. C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Atoian, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bazilevsky, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Eyser, O. [Brookhaven National Lab. (BNL), Upton, NY (United States); Kalinkin, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Kewisch, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Makdisi, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nemesure, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Poblaguev, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schmidke, W. B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Svirida, D. [Inst. of Theoretical and Experimental Physics (ITEP), Moscow (Russian Federation); Steski, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Webb, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zelenski, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tip, K. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    The spin physics program in Relativistic Heavy Ion Collider (RHIC) requires fast polarimeter to monitor the polarization evolution on the ramp and during stores. Over past decade, the polarimeter has evolved greatly to improve its performance. These include dual chamber design, monitoring camera, Si detector selection (and orientation), target quality control, and target frame modification. The preamp boards have been modified to deal with the high rate problem, too. The ultra thin carbon target lifetime is a concern. Simulations have been carried out on the target interaction with beam. Modification has also been done on the frame design. Extra caution has been put on RF shielding to deal with the pickup noises from the nearby stochastic cooling kickers. This paper summarizes the recent operation performance of this delicate device.

  13. Operation experience of p-Carbon polarimeter in RHIC

    International Nuclear Information System (INIS)

    The spin physics program in Relativistic Heavy Ion Collider (RHIC) requires fast polarimeter to monitor the polarization evolution on the ramp and during stores. Over past decade, the polarimeter has evolved greatly to improve its performance. These include dual chamber design, monitoring camera, Si detector selection (and orientation), target quality control, and target frame modification. The preamp boards have been modified to deal with the high rate problem, too. The ultra thin carbon target lifetime is a concern. Simulations have been carried out on the target interaction with beam. Modification has also been done on the frame design. Extra caution has been put on RF shielding to deal with the pickup noises from the nearby stochastic cooling kickers. This paper summarizes the recent operation performance of this delicate device.

  14. Development of a Thomson X-ray Polarimeter

    CERN Document Server

    V., Rishin P; R., Duraichelvan; James, Marykutty; Devasia, Jincy

    2010-01-01

    We describe the current status of the design and development of a Thomson X-ray polarimeter suitable for a small satellite mission. Currently we are considering two detector geometries, one using rectangular detectors placed on four sides of a scattering element and the other using a single cylindrical detector with the scattering element at the center. The rectangular detector configuration has been fabricated and tested. The cylindrical detector is currently under fabrication. In order to compensate any pointing offset of the satellite, a collimator with a flat topped response has been developed that provides a constant effective area over an angular range. We have also developed a double crystal monochromator/polariser for the purpose of test and calibration of the polarimeter. Preliminary test results from the developmental activities are presented here.

  15. Choosing and using astronomical eyepieces

    CERN Document Server

    Paolini, William

    2013-01-01

    This valuable reference fills a number of needs in the field of astronomical eyepieces, including that of a buyer's guide, observer's field guide and technical desk reference. It documents the past market for eyepieces and its evolution right up to the present day. In addition to appealing to practical astronomers - and potentially saving them money - it is useful both as a historical reference and as a detailed review of the current market place for this bustling astronomical consumer product. What distinguishes this book from other publications on astronomy is the involvement of observers from all aspects of the astronomical community, and also the major manufacturers of equipment. It not only catalogs the technical aspects of the many modern eyepieces but also documents amateur observer reactions and impressions of their utility over the years, using many different eyepieces. Eyepieces are the most talked-about accessories and collectible items available to the amateur astronomer. No other item of equi...

  16. Data acquisition system of Moller polarimeter hall a Jefferson lab

    International Nuclear Information System (INIS)

    The structure, parameters and test results of a new data acquisition system for Moller polarimeter based on flash- ADC are presented. Flash-ADC is electronic module in VME format that consists of high-speed multichannel ADC piped type and FPGA unit on board. The use of flash-ADC has a lot of advantages: reduce of cable interconnections, events registration with higher rate, considerable decreases of system deadtime and, as result, the accuracy of polarization measurements is increases.

  17. Demonstration of snapshot imaging polarimeter using modified Savart polariscopes.

    Science.gov (United States)

    Cao, Qizhi; Zhang, Jing; DeHoog, Edward; Zhang, Chunmin

    2016-02-10

    In an earlier publication, [Appl. Opt.51, 5791 (2012)] we demonstrated by theoretical analysis that a snapshot imaging polarimeter using modified Savart polariscopes (MSP-SIP) is comparable in carrier frequency, signal-to-noise ratio, and spatial resolution to a snapshot imaging polarimeter using conventional Savart polariscopes. In this investigation, numerical simulation is used to demonstrate the feasibility of MSP-SIP and investigate the limitation of the filtration and the Fourier analysis decoupling the polarization information encoded through the spatial modulation. In addition, a laboratory experiment is conducted to demonstrate the validity of MSP-SIP. The MSP-SIP operates on the principle of encoding polarization information within the spatial modulation of the image. This unique technology allows all Stokes parameters to be simultaneously recorded from every spatial position in an image with a single integration period of the imaging system. The device contains no moving parts and requires no scanning, allowing it to acquire data without the motion artifacts normally associated with a scanning polarimeter. In addition to snapshot imaging and static (no moving parts) capabilities, image processing is simple, and the device is compact and miniature. Therefore, we believe that MSP-SIP will be useful in many applications, such as remote sensing and bioscience.

  18. RHIC PC CNI POLARIMETER: EXPERIMENTAL SETUP AND PHYSICS RESULTS

    International Nuclear Information System (INIS)

    Acceleration of polarized proton beams and experiments with them at RHIC require fast and reliable measurements of the polarization. The polarimeter presented here uses very high figure of merit of the elastic pC scattering at very low momenta transfer since the cross section is large. Small (a few percent) analyzing power of the reaction makes it necessary to collect about 107 events per measurement. A deadtimeless DAQ system for the polarimeter is discussed in this paper. It is based on the waveform digitizer modules with ''on-board''' event analysis, resulting in typical polarization measurement times of several tens of seconds. During winter 2001/2002 RHIC polarized run several dedicated data runs were taken by the polarimeter to extract the form of the analyzing power dependence as a function of the momentum transferred at beam energies 24 and 100 GeV. This dependence is extremely important for the theoretical understanding of the CNI process including the contribution of the spin-flip hadronic amplitude. The new data may become an input to some theoretical models predicting the energy dependence of the analyzing power

  19. Astronomical Image and Data Analysis

    CERN Document Server

    Starck, J.-L

    2006-01-01

    With information and scale as central themes, this comprehensive survey explains how to handle real problems in astronomical data analysis using a modern arsenal of powerful techniques. It treats those innovative methods of image, signal, and data processing that are proving to be both effective and widely relevant. The authors are leaders in this rapidly developing field and draw upon decades of experience. They have been playing leading roles in international projects such as the Virtual Observatory and the Grid. The book addresses not only students and professional astronomers and astrophysicists, but also serious amateur astronomers and specialists in earth observation, medical imaging, and data mining. The coverage includes chapters or appendices on: detection and filtering; image compression; multichannel, multiscale, and catalog data analytical methods; wavelets transforms, Picard iteration, and software tools. This second edition of Starck and Murtagh's highly appreciated reference again deals with to...

  20. Two amateur astronomers at Berkeley

    CERN Document Server

    Sparavigna, Amelia Carolina

    2012-01-01

    The book on Mechanics of the Physics at Berkeley, by C. Kittel, W.D. Knight and M.A. Ruderman, is proposing at the end of its first chapter some problems of simple astronomy within the solar system. The discussion begins with two amateur astronomers who set for themselves the goal of determining the diameter and mass of the Sun. Here we discuss the problems proposed by the book and some other matters on ancient and modern astronomical studies of the solar system.

  1. Polarimeter Arrays with Comprehensive Frequency Coverage for the Next Generation of Precision Microwave Background Experiments

    Science.gov (United States)

    Austermann, Jason Edward; Beall, James; Becker, Dan; Cho, Hsiao-Mei; Duff, Shannon; gao, jiansong; Hilton, Gene; Hubmayr, Johannes; Irwin, Kent; li, dale; McKenney, Christopher; Ullom, Joel; van lanen, jeffrey; Vissers, Michael

    2016-06-01

    Spectral resolution at (sub-)millimeter wavelengths is now understood to be crucially important in precision measurements of the cosmic microwave background (CMB). Recent results from the Planck and BICEP/KECK experiments have established that measurements of the CMB polarization signal is limited, in part, by polarized foreground emission. In particular, polarized emission from galactic dust has been found to dominate and obscure potential signals of cosmic inflation, even in regions of the sky specifically identified as having relatively low galactic emission. Current and future experiments aim to address foreground contamination by conducting high-sensitivity observations with broad spectral coverage that will allow for differentiation within the measured signal between foreground sources of polarization and that of the CMB, which each have distinct spectral characteristics. To efficiently achieve these goals within a limited focal plane area, NIST-Boulder has developed multi-band TES-based polarimeters that simultaneously measure multiple spectral bands in each of two orthogonal polarizations. This acts to both increase pixel sensitivity through an increased total bandwidth, as well as providing broad spectral information for differentiation of emission sources. Here, we describe recent achievements and ongoing efforts at NIST-Boulder in the development of millimeter and sub-millimeter detector and focal plane technologies for future experiments, including the stage-IV CMB experiment, CMB-S4. NIST-Boulder provides critical cryogenic components to a large number of current and in-development CMB experiments. Recent milestones include the fielding of the first broadband multi-chroic mm-wave polarimeters in the ACTPol experiment, multi-band array fabrication on large-format 150 mm wafers, and development of matching 150 mm silicon platelet feedhorn arrays. We also review several related development efforts in detector, optical coupling, and readout technologies

  2. Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a polarized hard X-ray beam

    International Nuclear Information System (INIS)

    The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50-500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module containing a single CsI(Na) calorimeter element, at the center of the MAPMT, surrounded by 60 plastic elements. The prototype has been combined with custom readout electronics and software to create a complete 'engineering model' of the GRAPE instrument. This engineering model has been calibrated using a nearly 100% polarized hard X-ray beam at the Advanced Photon Source at Argonne National Laboratory. We find modulation factors of 0.46±0.06 and 0.48±0.03 at 69.5 and 129.5 keV, respectively, in good agreement with Monte Carlo simulations. In this paper we present details of the beam test, data analysis, and simulations, and discuss the implications of our results for the further development of the GRAPE concept.

  3. Australian sites of astronomical heritage

    Science.gov (United States)

    Stevenson, T.; Lomb, N.

    2015-03-01

    The heritage of astronomy in Australia has proven an effective communication medium. By interpreting science as a social and cultural phenomenon new light is thrown on challenges, such as the dispersal of instruments and problems identifying contemporary astronomy heritage. Astronomers are asked to take note and to consider the communication of astronomy now and in the future through a tangible heritage legacy.

  4. AIPY: Astronomical Interferometry in PYthon

    Science.gov (United States)

    Parsons, Aaron

    2016-09-01

    AIPY collects together tools for radio astronomical interferometry. In addition to pure-python phasing, calibration, imaging, and deconvolution code, this package includes interfaces to MIRIAD (ascl:1106.007) and HEALPix (ascl:1107.018), and math/fitting routines from SciPy.

  5. An Astronomical Data Analyzing Monitor

    Science.gov (United States)

    Teuber, D.

    ThP need for exchange of programmes and data between astronomical facilities is generally recognized, but practicable concepts concerning its realization are rare. Standardization of data formats through FITS is widely accepted; for (interactive) programs, however, identical hardware configurations seem to be the favoured solution. As an alternative, a software approach to the problem is presented.

  6. Combined retrievals of boreal forest fire aerosol properties with a polarimeter and lidar

    Directory of Open Access Journals (Sweden)

    K. Knobelspiesse

    2011-07-01

    Full Text Available Absorbing aerosols play an important, but uncertain, role in the global climate. Much of this uncertainty is due to a lack of adequate aerosol measurements. While great strides have been made in observational capability in the previous years and decades, it has become increasingly apparent that this development must continue. Scanning polarimeters have been designed to help resolve this issue by making accurate, multi-spectral, multi-angle polarized observations. This work involves the use of the Research Scanning Polarimeter (RSP. The RSP was designed as the airborne prototype for the Aerosol Polarimetery Sensor (APS, which was due to be launched as part of the (ultimately failed NASA Glory mission. Field observations with the RSP, however, have established that simultaneous retrievals of aerosol absorption and vertical distribution over bright land surfaces are quite uncertain. We test a merger of RSP and High Spectral Resolution Lidar (HSRL data with observations of boreal forest fire smoke, collected during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS. During ARCTAS, the RSP and HSRL instruments were mounted on the same aircraft, and validation data were provided by instruments on an aircraft flying a coordinated flight pattern. We found that the lidar data did indeed improve aerosol retrievals using an optimal estimation method, although not primarily because of the contraints imposed on the aerosol vertical distribution. The more useful piece of information from the HSRL was the total column aerosol optical depth, which was used to select the initial value (optimization starting point of the aerosol number concentration. When ground based sun photometer network climatologies of number concentration were used as an initial value, we found that roughly half of the retrievals had unrealistic sizes and imaginary indices, even though the retrieved spectral optical depths agreed within

  7. Development of a hard x-ray focal plane compton polarimeter: a compact polarimetric configuration with scintillators and Si photomultipliers

    Science.gov (United States)

    Chattopadhyay, T.; Vadawale, S. V.; Goyal, S. K.; Mithun, N. P. S.; Patel, A. R.; Shukla, R.; Ladiya, T.; Shanmugam, M.; Patel, V. R.; Ubale, G. P.

    2016-02-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm × 5 mm × 150 mm) which are read by Si Photomultiplier (SiPM). Use of the new generation SiPMs ensures the compactness of the instrument which is essential for the design of focal plane detectors. The expected sensitivity of such polarimetric configuration and complete characterization of the plastic scatterer, specially at lower energies have been discussed in [11, 13]. In this paper, we characterize the CsI(Tl) absorbers coupled to SiPM. We also present the experimental results from the fully assembled configuration of the Compton polarimeter.

  8. The 270 MeV deuteron beam polarimeter at the Nuclotron Internal Target Station

    Energy Technology Data Exchange (ETDEWEB)

    Kurilkin, P.K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Moscow State Institute of Radio-engineering Electronics and Automation (Technical University), Moscow (Russian Federation); Ladygin, V.P., E-mail: vladygin@jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Moscow State Institute of Radio-engineering Electronics and Automation (Technical University), Moscow (Russian Federation); Uesaka, T. [Center for Nuclear Study, University of Tokyo, Tokyo 113-0033 (Japan); Suda, K. [RIKEN Nishina Center, Saitama (Japan); Gurchin, Yu.V.; Isupov, A.Yu. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Itoh, K. [Department of Physics, Saitama University, Saitama (Japan); Janek, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Physics Department, University of Zilina, 010 26 Zilina (Slovakia); Karachuk, J.-T. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Advanced Research Institute for Electrical Engineering, Bucharest (Romania); Kawabata, T. [Center for Nuclear Study, University of Tokyo, Tokyo 113-0033 (Japan); Khrenov, A.N.; Kiselev, A.S.; Kizka, V.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kliman, J. [Institute of Physics of Slovak Academy of Sciences, Bratislava (Slovakia); Krasnov, V.A.; Livanov, A.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Nuclear Research, Moscow (Russian Federation); Maeda, Y. [Kyushi University, Hakozaki (Japan); Malakhov, A.I. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Matousek, V.; Morhach, M. [Institute of Physics of Slovak Academy of Sciences, Bratislava (Slovakia)

    2011-06-21

    A deuteron beam polarimeter has been constructed at the Internal Target Station at the Nuclotron of JINR. The polarimeter is based on spin-asymmetry measurements in the d-p elastic scattering at large angles and the deuteron kinetic energy of 270 MeV. It allows to measure vector and tensor components of the deuteron beam polarization simultaneously.

  9. Analysis of polarimeter data for the 2001-2002 RHIC run

    International Nuclear Information System (INIS)

    The results of several studies of the 200-MeV (LINAC), AGS (E880), and RHIC polarimeter data from the polarized proton run in 2001/2002 are presented. Much of this work occurred during or immediately after the run. Some of these analyses have implications for the understanding of the performance of the polarized ion source, AGS, and RHIC with polarized protons. Some of the conclusions include: (A) A recalibration of the 200-MeV polarimeter gives results consistent with the older calibration, but high rates in the 200-MeV polarimeter are still a problem. (B) No evidence of sizable systematic effects was found in several tests of the AGS polarimeter with a thin carbon fiber target. (C) Significant polarization loss in the AGS was observed above Gγ = 7.5 but not between injection and Gγ = 7.5. (D) The magnitude of the flattop asymmetry in the RHIC polarimeters decreases with time in a fill. (E) The RHIC polarimeter analyzing power on flattop is greater than or equal to that at injection. (F) Unexplained systematic effects were observed in the RHIC polarimeter, but the implications for the measured polarization asymmetry are not clear. These effects were not isolated events, but occurred throughout the run. Conceivably the data could indicate that the present RHIC polarimeter design will not be able to achieve a goal of a ± 5% measurement of the beam polarization

  10. A New Cost-Effective Diode Laser Polarimeter Apparatus Constructed by Undergraduate Students

    Science.gov (United States)

    Lisboa, Pedro; Sotomayor, Joo; Ribeiro, Paulo

    2010-01-01

    The construction of a diode laser polarimeter apparatus by undergraduate students is described. The construction of the modular apparatus by undergraduate students gives them an insight into how it works and how the measurement of a physical or chemical property is conducted. The students use the polarimeter to obtain rotation angle values for the…

  11. Engaging Students through Astronomically Inspired Music

    Science.gov (United States)

    Whitehouse, M.

    2011-09-01

    This paper describes a lesson outline in which astronomically inspired musical compositions are used to teach astronomical concepts via an introductory activity, close listening, and critical/creative reflection.

  12. The astronomical tables of Giovanni Bianchini

    CERN Document Server

    Chabas, Jose

    2009-01-01

    This book describes and analyses, for the first time, the astronomical tables of Giovanni Bianchini of Ferrara (d. after 1469), explains their context, inserts them into an astronomical tradition that began in Toledo, and addresses their diffusion.

  13. Interactive Visualization and Simulation of Astronomical Nebulae

    CERN Document Server

    Wenger, Stephan; Steffen, Wolfgang; Koning, Nico; Weiskopf, Daniel; Magnor, Marcus

    2012-01-01

    Interactive visualization and simulation of astrophysical phenomena help astronomers and enable digital planetariums and television documentaries to take their spectators on a journey into deep space to explore the astronomical wonders of our universe in 3D.

  14. Environmental effects on lunar astronomical observatories

    Science.gov (United States)

    Johnson, Stewart W.; Taylor, G. Jeffrey; Wetzel, John P.

    1992-01-01

    The Moon offers a stable platform with excellent seeing conditions for astronomical observations. Some troublesome aspects of the lunar environment will need to be overcome to realize the full potential of the Moon as an observatory site. Mitigation of negative effects of vacuum, thermal radiation, dust, and micrometeorite impact is feasible with careful engineering and operational planning. Shields against impact, dust, and solar radiation need to be developed. Means of restoring degraded surfaces are probably essential for optical and thermal control surfaces deployed in long-lifetime lunar facilities. Precursor missions should be planned to validate and enhance the understanding of the lunar environment (e.g., dust behavior without and with human presence) and to determine environmental effects on surfaces and components. Precursor missions should generate data useful in establishing keepout zones around observatory facilities where rocket launches and landings, mining, and vehicular traffic could be detrimental to observatory operation.

  15. Learning Vector Quantization for Classifying Astronomical Objects

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The sizes of astronomical surveys in different wavebands are increas-ing rapidly. Therefore, automatic classification of objects is becoming ever moreimportant. We explore the performance of learning vector quantization (LVQ) inclassifying multi-wavelength data. Our analysis concentrates on separating activesources from non-active ones. Different classes of X-ray emitters populate distinctregions of a multidimensional parameter space. In order to explore the distributionof various objects in a multidimensional parameter space, we positionally cross-correlate the data of quasars, BL Lacs, active galaxies, stars and normal galaxiesin the optical, X-ray and infrared bands. We then apply LVQ to classify them withthe obtained data. Our results show that LVQ is an effective method for separatingAGNs from stars and normal galaxies with multi-wavelength data.

  16. Optimization, tolerance analysis and implementation of a Stokes polarimeter based on the conical refraction phenomenon.

    Science.gov (United States)

    Peinado, Alba; Lizana, Angel; Turpín, Alejandro; Iemmi, Claudio; Kalkandjiev, Todor K; Mompart, Jordi; Campos, Juan

    2015-03-01

    Recently, we introduced the basic concepts behind a new polarimeter device based on conical refraction (CR), which presents several appealing features compared to standard polarimeters. To name some of them, CR polarimeters retrieve the polarization state of an input light beam with a snapshot measurement, allow for substantially enhancing the data redundancy without increasing the measuring time, and avoid instrumental errors owing to rotating elements or phase-to-voltage calibration typical from dynamic devices. In this article, we present a comprehensive study of the optimization, robustness and parameters tolerance of CR based polarimeters. In addition, a particular CR based polarimetric architecture is experimentally implemented, and some concerns and recommendations are provided. Finally, the implemented polarimeter is experimentally tested by measuring different states of polarization, including fully and partially polarized light.

  17. Astronomical calibration of the Maastrichtian (Late Cretaceous)

    DEFF Research Database (Denmark)

    Husson, Dorothée; Galbrun, Bruno; Laskar, Jacques;

    2011-01-01

    Recent improvements to astronomical modeling of the Solar System have contributed to important refinements of the Cenozoic time scale through astronomical calibration of sedimentary series. We extend this astronomical calibration into the Cretaceous, on the base of the 405 ka orbital eccentricity...

  18. A cylindrically symmetric "micro-Mott" electron polarimeter.

    Science.gov (United States)

    Clayburn, N B; Brunkow, E; Burtwistle, S J; Rutherford, G H; Gay, T J

    2016-05-01

    A small, novel, cylindrically symmetric Mott electron polarimeter is described. The effective Sherman function, Seff, or analyzing power, for 20 kV Au target bias with a 1.3 keV energy loss window is 0.16 ± 0.01, where uncertainty in the measurement is due primarily to uncertainty in the incident electron polarization. For an energy loss window of 0.5 keV, Seff reaches its maximum value of 0.24 ± 0.02. The device's maximum efficiency, I/Io, defined as the detected count rate divided by the incident particle rate, is 3.7 ± 0.2 × 10(-4) at 20 keV. The figure-of-merit of the device, η, is defined as Seff (2)IIo and equals 9.0 ± 1.6 × 10(-6). Potential sources of false asymmetries due to detector electronic asymmetry and beam misalignment have been investigated. The new polarimeter's performance is compared to published results for similar compact retarding-field Mott polarimeters, and it is concluded that this device has a relatively large Seff and low efficiency. SIMION(®) electron trajectory simulations and Sherman function calculations are presented to explain the differences in performance between this device and previous designs. This design has an Seff that is insensitive to spatial beam fluctuations and, for an energy loss window >0.5 keV, negligible background due to spurious ion and X-ray production at the target. PMID:27250409

  19. Hard X-ray Imaging Polarimeter for PolariS

    Science.gov (United States)

    Hayashida, Kiyoshi

    2016-07-01

    We present the current status of development of hard X-ray imaging polarimeters for the small satellite mission PolariS. The primary aim of PolariS is hard X-ray (10-80keV) polarimetry of sources brighter than 10mCrab. Its targets include stellar black holes, neutron stars, super nova remnants, and active galactic nuclei. This aim is enabled with three sets of hard X-ray telescopes and imaging polarimeters installed on their focal planes. The imaging polarimeter consists of two kinds of (plastic and GSO) scintillator pillars and multi-anode photo multiplier tubes (MAPMTs). When an X-ray photon incident to a plastic scintillator cause a Compton scattering, a recoiled electron makes a signal on the corresponding MAPMT pixel, and a scatted X-rays absorbed in surrounding GSO makes another signal. This provide information on the incident position and the scattered direction. The latter information is employed for polarimetry. For 20keV X-ray incidence, the recoiled electron energy is as low as 1keV. Thus, the performance of this imaging polarimeter is primarily determined by the efficiency that we can detect low level signal of recoiled electrons generated in plastic scintillators. The efficiency could depend on multiple factors, e.g. quenching of light in scintillators, electric noise, pedestal error, cross talk of the lights to adjacent MAPMT pixels, MAPMT dark current etc. In this paper, we examined these process experimentally and optimize the event selection algorithm, in which single photo-electron events are selected. We then performed an X-ray (10-80keV monochromatic polarized beam) irradiation test at a synchrotron facility. The modulation contrast (M) is about 60% in 15-80keV range. We succeeded in detecting recoiled electrons for 10-80keV X-ray incidence, though detection efficiency is lower at lowest end of the energy range. Expected MDP will also be shown.

  20. Overdetermined broadband spectroscopic Mueller matrix polarimeter designed by genetic algorithms.

    Science.gov (United States)

    Aas, Lars Martin Sandvik; Ellingsen, Pål Gunnar; Fladmark, Bent Even; Letnes, Paul Anton; Kildemo, Morten

    2013-04-01

    This paper reports on the design and implementation of a liquid crystal variable retarder based overdetermined spectroscopic Mueller matrix polarimeter, with parallel processing of all wavelengths. The system was designed using a modified version of a recently developed genetic algorithm [Letnes et al. Opt. Express 18, 22, 23095 (2010)]. A generalization of the eigenvalue calibration method is reported that allows the calibration of such overdetermined polarimetric systems. Out of several possible designs, one of the designs was experimentally implemented and calibrated. It is reported that the instrument demonstrated good performance, with a measurement accuracy in the range of 0.1% for the measurement of air. PMID:23571964

  1. National Astronomical Observatory of Japan

    CERN Document Server

    Haubold, Hans J; UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan

    2010-01-01

    This book represents Volume II of the Proceedings of the UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan, Tokyo, 18 - 22 June, 2007. It covers two programme topics explored in this and past workshops of this nature: (i) non-extensive statistical mechanics as applicable to astrophysics, addressing q-distribution, fractional reaction and diffusion, and the reaction coefficient, as well as the Mittag-Leffler function and (ii) the TRIPOD concept, developed for astronomical telescope facilities. The companion publication, Volume I of the proceedings of this workshop, is a special issue in the journal Earth, Moon, and Planets, Volume 104, Numbers 1-4, April 2009.

  2. Geopulsation, Volcanism and Astronomical Periods

    Institute of Scientific and Technical Information of China (English)

    Yang Xuexiang; Chen Dianyou; Yang Xiaoying; Yang Shuchen

    2000-01-01

    Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.

  3. Astronomical Signatures of Dark Matter

    OpenAIRE

    Paul Gorenstein; Wallace Tucker

    2014-01-01

    Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitti...

  4. Euler: Genius Blind Astronomer Mathematician

    OpenAIRE

    Musielak, Dora

    2014-01-01

    Leonhard Euler, the most prolific mathematician in history, contributed to advance a wide spectrum of topics in celestial mechanics. At the Saint Petersburg Observatory, Euler observed sunspots and tracked the movements of the Moon. Combining astronomical observations with his own mathematical genius, he determined the orbits of planets and comets. Euler laid the foundations of the methods of planetary perturbations and solved many of the Newtonian mechanics problems of the eighteenth century...

  5. Armenian Astronomical Society Annual Activities in 2014

    Science.gov (United States)

    Mickaelian, A. M.

    2015-07-01

    A report is given on the achievements of the Armenian astronomy during the last year and on the present activities of the Armenian Astronomical Society (ArAS). ArAS membership, ArAS electronic newsletters (ArASNews), ArAS webpage, annual meetings, Annual Prize for Young Astronomers (Yervant Terzian Prize) and other awards, international relations, presence in international organizations, summer schools, astronomical Olympiads and other events, matters related to astronomical education, astronomical heritage, astronomy outreach and ArAS further projects are discussed. The present meeting, BAO Science Camp, ArAS School lectures are among 2014 events as well.

  6. Conceptual approach to astronomical problems

    Science.gov (United States)

    Skvortsov, N. A.; Avvakumova, E. A.; Bryukhov, D. O.; Vovchenko, A. E.; Vol'nova, A. A.; Dluzhnevskaya, O. B.; Kaigorodov, P. V.; Kalinichenko, L. A.; Kniazev, A. Yu.; Kovaleva, D. A.; Malkov, O. Yu.; Pozanenko, A. S.; Stupnikov, S. A.

    2016-01-01

    New technical capabilities have brought about the sweeping growth of the amount of data acquired by the astronomers from observations with different instruments in various parts of the electromagnetic spectrum. We consider conceptual approach to be a promising tool to efficiently deal with these data. It uses problem domain knowledge to formulate the tasks and develop problem-solving algorithms and data analysis methods in terms of domain concepts without reference to particular data sources, and thereby allows solving certain problems in general form. We demonstrate the benefits of conceptual approach by using it to solve problems related to search for secondary photometric standard candidates, determination of galaxy redshifts, creation of a binary and multiple star repository based on inhomogeneous databases, and classification of eclipsing binaries.We formulate and solve these problems over specifications of astronomical knowledge units such as photometric systems, astronomical objects, multiple stars, etc., and define them in terms of the corresponding problem domains independently of the existing data resources.

  7. Development of a Hard X-ray focal plane Compton Polarimeter: A compact polarimetric configuration with Scintillators and Si photomultipliers

    CERN Document Server

    Chattopadhyay, T; Goyal, S K; S., Mithun N P; Patel, A R; Shukla, R; Ladiya, T; Shanmugam, M; Patel, V R; Ubale, G P

    2015-01-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm x...

  8. Internal magnetic field measurements by laser-based POlarimeter-INTerferometer (POINT) system on EAST

    Science.gov (United States)

    Liu, H. Q.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Zou, Z. Y.; Qian, J. P.; Li, W. M.; Yang, Y.; Zeng, L.; Zhang, S. B.; Lan, T.; Wang, S. X.; Hanada, K.; Wei, X. C.; Hu, L. Q.; Wan, B. N.

    2016-01-01

    A multi-channel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for fully diagnosing the internal magnetic field in the EAST tokamak. Double-pass, horizontal, radially-viewing chords access the plasma via an equatorial port. The laser source consists of three CW formic acid (HCOOH) FIR lasers at nominal wavelength 432.5 μm which are optically pumped by independent infrared CO2 lasers. Output power is more than 30 mW of per cavity. Novel molybdenum retro-reflectors, can with withstand baking temperature up to 350°C and discharge duration more than 1000 s, are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which provide real-time Faraday rotation angle and density phase shift output for plasma control, have been developed for the POINT system. Reliability of both polarimetric and interferometric measurement are obtained in 22 s long pulse H mode discharge and 8 s NBI H mode discharge, indicating the POINT system works for any heating scheme on EAST so far. The electron line-integrated density resolution of POINT is less than 1 × 1016 m-2 (implemented in the plasma control system in the future.

  9. GRAPE - A Balloon-Borne Gamma-Ray Polarimeter Experiment

    CERN Document Server

    Bloser, P F; Macri, J R; McConnell, M L; Narita, T; Ryan, J M

    2005-01-01

    This paper reviews the development status of GRAPE (the Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The purpose of GRAPE is to measure the polarization of hard X-rays in the 50-300 keV energy range. We are particularly interested in X-rays that are emitted from solar flares and gamma-ray bursts (GRBs), although GRAPE could also be employed in the study of other astrophysical sources. Accurately measuring the polarization of the emitted radiation will lead to a better understating of both emission mechanisms and source geometries. The GRAPE design consists of an array of plastic scintillators surrounding a central high-Z crystal scintillator. The azimuthal distribution of photon scatters from the plastic array into the central calorimeter provides a measure of the polarization fraction and polarization angle of the incident radiation. The design of the detector provides sensitivity over a large field-of-view (>pi steradian). The design facilitates the fabrication of large area arrays w...

  10. A Cosmic Microwave Background Radiation Polarimeter Using Superconducting Bearings

    CERN Document Server

    Hanany, S; Johnson, B; Jones, T; Hull, J R; Ma, K B

    2003-01-01

    Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured the coefficient of friction as a function of several parameters including temperature between 15 and 80 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm, and ambient pressure between 10^{-7} and 1 torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.

  11. Unique electron polarimeter analyzing power comparison and precision spin-based energy measurement

    International Nuclear Information System (INIS)

    Precision measurements of the relative analyzing powers of five electron beam polarimeters, based on Compton, Moller, and Mott scattering, have been performed using the CEBAF accelerator at the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory). A Wien filter in the 100 keV beamline of the injector was used to vary the electron spin orientation exiting the injector. High statistical precision measurements of the scattering asymmetry as a function of the spin orientation were made with each polarimeter. Since each polarimeter receives beam with the same magnitude of polarization, these asymmetry measurements permit a high statistical precision comparison of the relative analyzing powers of the five polarimeters. This is the first time a precise comparison of the analyzing powers of Compton, Moller, and Mott scattering polarimeters has been made. Statistically significant disagreements among the values of the beam polarization calculated from the asymmetry measurements made with each polarimeter reveal either errors in the values of the analyzing power, or failure to correctly include all systematic effects. The measurements reported here represent a first step toward understanding the systematic effects of these electron polarimeters. Such studies are necessary to realize high absolute accuracy (ca. 1%) electron polarization measurements, as required for some parity violation measurements planned at Jefferson Laboratory. Finally, a comparison of the value of the spin orientation exiting the injector that provides maximum longitudinal polarization in each experimental hall leads to an independent and very precise (better than 10-4) absolute measurement of the final electron beam energy

  12. Preliminary Neutronics Analysis of the ITER Toroidal Interferometer and Polarimeter Diagnostic Corner Cube Retroreflectors

    Energy Technology Data Exchange (ETDEWEB)

    Tresemer, K. R.

    2015-07-01

    ITER is an international project under construction in France that will demonstrate nuclear fusion at a power plant-relevant scale. The Toroidal Interferometer and Polarimeter (TIP) Diagnostic will be used to measure the plasma electron line density along 5 laser-beam chords. This line-averaged density measurement will be input to the ITER feedback-control system. The TIP is considered the primary diagnostic for these measurements, which are needed for basic ITER machine control. Therefore, system reliability & accuracy is a critical element in TIP’s design. There are two major challenges to the reliability of the TIP system. First is the survivability and performance of in-vessel optics and second is maintaining optical alignment over long optical paths and large vessel movements. Both of these issues greatly depend on minimizing the overall distortion due to neutron & gamma heating of the Corner Cube Retroreflectors (CCRs). These are small optical mirrors embedded in five first wall locations around the vacuum vessel, corresponding to certain plasma tangency radii. During the development of the design and location of these CCRs, several iterations of neutronics analyses were performed to determine and minimize the total distortion due to nuclear heating of the CCRs. The CCR corresponding to TIP Channel 2 was chosen for analysis as a good middle-road case, being an average distance from the plasma (of the five channels) and having moderate neutron shielding from its blanket shield housing. Results show that Channel 2 meets the requirements of the TIP Diagnostic, but barely. These results suggest other CCRs might be at risk of exceeding thermal deformation due to nuclear heating.

  13. Astronomical measurement a concise guide

    CERN Document Server

    Lawrence, Andy

    2014-01-01

    This book on astronomical measurement takes a fresh approach to teaching the subject. After discussing some general principles, it follows the chain of measurement through atmosphere, imaging, detection, spectroscopy, timing, and hypothesis testing. The various wavelength regimes are covered in each section, emphasising what is the same, and what is different. The author concentrates on the physics of detection and the principles of measurement, aiming to make this logically coherent. The book is based on a short self contained lecture course for advanced undergraduate students developed and taught by the author over several years.

  14. Visualizing Astronomical Data with Blender

    Science.gov (United States)

    Kent, Brian R.

    2014-01-01

    We present methods for using the 3D graphics program Blender in the visualization of astronomical data. The software's forte for animating 3D data lends itself well to use in astronomy. The Blender graphical user interface and Python scripting capabilities can be utilized in the generation of models for data cubes, catalogs, simulations, and surface maps. We review methods for data import, 2D and 3D voxel texture applications, animations, camera movement, and composite renders. Rendering times can be improved by using graphic processing units (GPUs). A number of examples are shown using the software features most applicable to various kinds of data paradigms in astronomy.

  15. Focus on astronomical predictable events

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2006-01-01

    At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...... the public and makes a point of interest in a small exhibit area. A countdown clock can be simple, but it is possible to expand the concept to an eye-catching part of a museum....

  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. astroplan: Observation Planning for Astronomers

    Science.gov (United States)

    Morris, Brett

    2016-03-01

    Astroplan is an observation planning package for astronomers. It is an astropy-affiliated package which began as a Google Summer of Code project. Astroplan facilitates convenient calculation of common observational quantities, like target altitudes and azimuths, airmasses, and rise/set times. Astroplan also computes when targets are observable given various extensible observing constraints, for example: within a range of airmasses or altitudes, or at a given separation from the Moon. Astroplan is taught in the undergraduate programming for astronomy class, and enables observational Pre- MAP projects at the University of Washington. In the near future, we plan to implement scheduling capabilities in astroplan on top of the constraints framework.

  18. Explanatory supplement to the astronomical almanac

    CERN Document Server

    Urban, Sean E

    2013-01-01

    The Explanatory Supplement to the Astronomical Almanac offers explanatory material, supplemental information and detailed descriptions of the computational models and algorithms used to produce The Astronomical Almanac, which is an annual publication prepared jointly by the US Naval Observatory and Her Majesty's Nautical Almanac Office in the UK. Like The Astronomical Almanac, The Explanatory Supplement provides detailed coverage of modern positional astronomy. Chapters are devoted to the celestial and terrestrial reference frames, orbital ephemerides, precession, nutation, Earth rotation, and coordinate transformations. These topics have undergone substantial revisions since the last edition was published. Astronomical positions are intertwined with timescales and relativity in The Astronomical Almanac, so related chapters are provided in The Explanatory Supplement. The Astronomical Almanac also includes information on lunar and solar eclipses, physical ephemerides of solar system bodies, and calendars, so T...

  19. The Infrared Astronomical Mission AKARI

    CERN Document Server

    Murakami, H; Barthel, P; Clements, D L; Cohen, M; Doi, Y; Enya, K; Figueredo, E; Fujishiro, N; Fujiwara, H; Fujiwara, M; García-Lario, P; Goto, T; Hasegawa, S; Hibi, Y; Hirao, T; Hiromoto, N; Hong, S S; Imai, K; Ishigaki, M; Ishiguro, M; Ishihara, D; Ita, Y; Jeong, W -S; Jeong, K S; Kaneda, H; Kataza, H; Kawada, M; Kawai, T; Kawamura, A; Kessler, M F; Kester, Do; Kii, T; Kim, D C; Kim, W; Kobayashi, H; Koo, B C; Kwon, S M; Lee, H M; Lorente, R; Makiuti, S; Matsuhara, H; Matsumoto, T; Matsuo, H; Matsuura, S; Müller, T G; Murakami, N; Nagata, H; Nakagawa, T; Naoi, T; Narita, M; Noda, M; Oh, S H; Ohnishi, A; Ohyama, Y; Okada, Y; Okuda, H; Oliver, S; Onaka, T; Ootsubo, T; Oyabu, S; Pak, S; Park, Y S; Pearson, C P; Rowan-Robinson, M; Saitô, T; Sakon, I; Salama, A; Sato, S; Savage, R S; Serjeant, S; Shibai, H; Shirahata, M; Sohn, J J; Suzuki, T; Takagi, T; Takahashi, H; Tanabé, T; Takeuchi, T T; Takita, S; Thomson, M; Uemizu, K; Ueno, M; Usui, F; Verdugo, E; Wada, T; Wang, L; Watabe, T; Watarai, H; White, G J; Yamamura, I; Yamauchi, C; Yasuda, A

    2007-01-01

    AKARI, the first Japanese satellite dedicated to infrared astronomy, was launched on 2006 February 21, and started observations in May of the same year. AKARI has a 68.5 cm cooled telescope, together with two focal-plane instruments, which survey the sky in six wavelength bands from the mid- to far-infrared. The instruments also have the capability for imaging and spectroscopy in the wavelength range 2 - 180 micron in the pointed observation mode, occasionally inserted into the continuous survey operation. The in-orbit cryogen lifetime is expected to be one and a half years. The All-Sky Survey will cover more than 90 percent of the whole sky with higher spatial resolution and wider wavelength coverage than that of the previous IRAS all-sky survey. Point source catalogues of the All-Sky Survey will be released to the astronomical community. The pointed observations will be used for deep surveys of selected sky areas and systematic observations of important astronomical targets. These will become an additional ...

  20. Processing Color in Astronomical Imagery

    CERN Document Server

    Arcand, Kimberly K; Rector, Travis; Levay, Zoltan G; DePasquale, Joseph; Smarr, Olivia

    2013-01-01

    Every year, hundreds of images from telescopes on the ground and in space are released to the public, making their way into popular culture through everything from computer screens to postage stamps. These images span the entire electromagnetic spectrum from radio waves to infrared light to X-rays and gamma rays, a majority of which is undetectable to the human eye without technology. Once these data are collected, one or more specialists must process the data to create an image. Therefore, the creation of astronomical imagery involves a series of choices. How do these choices affect the comprehension of the science behind the images? What is the best way to represent data to a non-expert? Should these choices be based on aesthetics, scientific veracity, or is it possible to satisfy both? This paper reviews just one choice out of the many made by astronomical image processors: color. The choice of color is one of the most fundamental when creating an image taken with modern telescopes. We briefly explore the ...

  1. LGBT Workplace Issues for Astronomers

    Science.gov (United States)

    Kay, Laura E.; Danner, R.; Sellgren, K.; Dixon, V.; GLBTQastro

    2011-01-01

    Federal Equal Employment Opportunity laws and regulations do not provide protection from discrimination on the basis of sexual orientation or gender identity or gender expression. Sexual minority astronomers (including lesbian, gay, bisexual and transgender people; LGBT) can face additional challenges at school and work. Studies show that LGBT students on many campuses report experiences of harassment. Cities, counties, and states may or may not have statutes to protect against such discrimination. There is wide variation in how states and insurance plans handle legal and medical issues for transgender people. Federal law does not acknowledge same-sex partners, including those legally married in the U.S. or in other countries. Immigration rules in the U.S. (and many other, but not all) countries do not recognize same-sex partners for visas, employment, etc. State `defense of marriage act' laws have been used to remove existing domestic partner benefits at some institutions, or benefits can disappear with a change in governor. LGBT astronomers who change schools, institutions, or countries during their career may experience significant differences in their legal, medical, and marital status.

  2. Astronomers in the Chemist's War

    Science.gov (United States)

    Trimble, Virginia L.

    2012-01-01

    World War II, with radar, rockets, and "atomic" bombs was the physicists' war. And many of us know, or think we know, what our more senior colleagues did during it, with Hubble and Hoffleit at Aberdeen; M. Schwarzschild on active duty in Italy; Bondi, Gold, and Hoyle hunkered down in Dunsfeld, Surrey, talking about radar, and perhaps steady state; Greenstein and Henyey designing all-sky cameras; and many astronomers teaching navigation. World War I was The Chemists' War, featuring poison gases, the need to produce liquid fuels from coal on one side of the English Channel and to replace previously-imported dyesstuffs on the other. The talke will focus on what astronomers did and had done to them between 1914 and 1919, from Freundlich (taken prisoner on an eclipse expedition days after the outbreak of hostilities) to Edwin Hubble, returning from France without ever having quite reached the front lines. Other events bore richer fruit (Hale and the National Research Council), but very few of the stories are happy ones. Most of us have neither first nor second hand memories of The Chemists' War, but I had the pleasure of dining with a former Freundlich student a couple of weeks ago.

  3. Astronomical Signatures of Dark Matter

    Directory of Open Access Journals (Sweden)

    Paul Gorenstein

    2014-01-01

    Full Text Available Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of dark matter consistent with other estimates. The unambiguous detection of dark matter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century.

  4. Astronomical Image Compression Techniques Based on ACC and KLT Coder

    Directory of Open Access Journals (Sweden)

    J. Schindler

    2011-01-01

    Full Text Available This paper deals with a compression of image data in applications in astronomy. Astronomical images have typical specific properties — high grayscale bit depth, size, noise occurrence and special processing algorithms. They belong to the class of scientific images. Their processing and compression is quite different from the classical approach of multimedia image processing. The database of images from BOOTES (Burst Observer and Optical Transient Exploring System has been chosen as a source of the testing signal. BOOTES is a Czech-Spanish robotic telescope for observing AGN (active galactic nuclei and the optical transient of GRB (gamma ray bursts searching. This paper discusses an approach based on an analysis of statistical properties of image data. A comparison of two irrelevancy reduction methods is presented from a scientific (astrometric and photometric point of view. The first method is based on a statistical approach, using the Karhunen-Loeve transform (KLT with uniform quantization in the spectral domain. The second technique is derived from wavelet decomposition with adaptive selection of used prediction coefficients. Finally, the comparison of three redundancy reduction methods is discussed. Multimedia format JPEG2000 and HCOMPRESS, designed especially for astronomical images, are compared with the new Astronomical Context Coder (ACC coder based on adaptive median regression.

  5. Astronomical Symbolism in Australian Aboriginal Rock Art

    CERN Document Server

    Norris, Ray P

    2010-01-01

    Traditional Aboriginal Australian cultures include a significant astronomical component, perpetuated through oral tradition and ceremony. This knowledge has practical navigational and calendrical functions, and sometimes extends to a deep understanding of the motion of objects in the sky. Here we explore whether this astronomical tradition is reflected in the rock art of Aboriginal Australians. We find several plausible examples of depictions of astronomical figures and symbols, and also evidence that astronomical observations were used to set out stone arrangements. However, we recognise that the case is not yet strong enough to make an unequivocal statement, and describe our plans for further research.

  6. Preflight performance studies of the PoGOLite hard X-ray polarimeter

    CERN Document Server

    Chauvin, M; Kawano, T; Kiss, M; Kole, M; Mikhalev, V; Moretti, E; Takahashi, H; Pearce, M

    2015-01-01

    Polarimetric studies of astrophysical sources can make important contributions to resolve the geometry of the emitting region and determine the photon emission mechanism. PoGOLite is a balloon-borne polarimeter operating in the hard X-ray band (25-240 keV), with a Pathfinder mission focussing on Crab observations. Within the polarimeter, the distribution of Compton scattering angles is used to determine the polarisation fraction and angle of incident photons. To assure an unbiased measurement of the polarisation during a balloon flight it is crucial to characterise the performance of the instrument before the launch. This paper presents the results of the PoGOLite calibration tests and simulations performed before the 2013 balloon flight. The tests performed confirm that the polarimeter does not have any intrinsic asymmetries and therefore does not induce bias into the measurements. Generally, good agreement is found between results from test data and simulations which allows the polarimeter performance to be...

  7. The Hertz/VPM polarimeter: Design and first light observations

    CERN Document Server

    Krejny, Megan; d'Aubigny, Christian Drouet; Golish, Dathon; Houde, Martin; Hui, Howard; Kulesa, Craig; Loewenstein, Robert F; Moseley, S Harvey; Novak, Giles; Voellmer, George; Walker, Chris; Wollack, Ed

    2008-01-01

    We present first results of Hertz/VPM, the first submillimeter polarimeter employing the dual Variable-delay Polarization Modulator (dual-VPM). This device differs from previously used polarization modulators in that it operates in translation rather than mechanical rotation. We discuss the basic theory behind this device, and its potential advantages over the commonly used half wave plate (HWP). The dual-VPM was tested both at the Submillimeter Telescope Observatory (SMTO) and in the lab. In each case we present a detailed description of the setup. We discovered nonideal behavior in the system. This is at least in part due to properties of the VPM wire grids (diameter, spacing) employed in our experiment. Despite this, we found that the dual-VPM system is robust, operating with high efficiency and low instrumental polarization. This device is well suited for air and space-borne applications.

  8. Foreground-Induced Biases in CMB Polarimeter Self-Calibration

    CERN Document Server

    Abitbol, M H; Johnson, B R

    2015-01-01

    Precise polarisation measurements of the cosmic microwave background (CMB) require accurate knowledge of the instrument orientation relative to the sky frame used to define the cosmological Stokes parameters. Suitable celestial calibration sources that could be used to measure the polarimeter orientation angle are limited, so current experiments commonly `self-calibrate.' The self-calibration method exploits the theoretical fact that the $EB$ and $TB$ cross-spectra of the CMB vanish in the standard cosmological model, so any detected $EB$ and $TB$ signals must be due to systematic errors. However, this assumption neglects the fact that polarized Galactic foregrounds in a given portion of the sky may have non-zero $EB$ and $TB$ cross-spectra. If these foreground signals remain in the observations, then they will bias the self-calibrated telescope polarisation angle and produce a spurious $B$-mode signal. In this paper we estimate the foreground-induced bias for various instrument configurations and then expand...

  9. Two-dimensional solar spectropolarimetry with the KIS/IAA Visible Imaging Polarimeter

    Science.gov (United States)

    Beck, C.; Bellot Rubio, L. R.; Kentischer, T. J.; Tritschler, A.; Del Toro Iniesta, J. C.

    2010-09-01

    Context. Spectropolarimetry at high spatial and spectral resolution is a basic tool to characterize the magnetic properties of the solar atmosphere. Aims: We introduce the KIS/IAA Visible Imaging Polarimeter (VIP), a new post-focus instrument that upgrades the TESOS spectrometer at the German Vacuum Tower Telescope (VTT) into a full vector polarimeter. VIP is a collaboration between the Kiepenheuer Institut für Sonnenphysik (KIS) and the Instituto de Astrofísica de Andalucía (IAA-CSIC). Methods: We describe the optical setup of VIP, the data acquisition procedure, and the calibration of the spectropolarimetric measurements. We show examples of data taken between 2005 and 2008 to illustrate the potential of the instrument. Results: VIP is capable of measuring the four Stokes profiles of spectral lines in the range from 420 to 700 nm with a spatial resolution better than 0farcs5. Lines can be sampled at 40 wavelength positions in 60 s, achieving a noise level of about 2 × 10-3 with exposure times of 300 ms and pixel sizes of 0farcs17 × 0farcs17 (2 × 2 binning). The polarization modulation is stable over periods of a few days, ensuring high polarimetric accuracy. The excellent spectral resolution of TESOS allows the use of sophisticated data analysis techniques such as Stokes inversions. One of the first scientific results of VIP presented here is that the ribbon-like magnetic structures of the network are associated with a distinct pattern of net circular polarization away from disk center. Conclusions: VIP performs spectropolarimetric measurements of solar magnetic fields at a spatial resolution that is only slightly worse than that of the Hinode spectropolarimeter, while providing a 2D field field of view and the possibility to observe up to four spectral regions sequentially with high cadence. VIP can be used as a stand-alone instrument or in combination with other spectropolarimeters and imaging systems of the VTT for extended wavelength coverage.

  10. Multichannel spin polarimeter for energy- and angle-dispersive photoemission measurements

    International Nuclear Information System (INIS)

    Spin polarization measurements of free electrons remain challenging since their first realization by Mott. The relevant quantity of a spin polarimeter is its figure of merit, FoM=S2I/I0, with the asymmetry function S and the ratio between scattered and primary intensity I/I0. State-of-the-art devices are based on single-channel scattering (spin-orbit or exchange interaction) which is characterized by FoM ≅10-4. On the other hand, modern hemispherical analyzers feature an efficient multichannel detection of spin-integral intensity with more than 104 data points simultaneously. In comparison between spin-resolved and spin-integral electron spectroscopy we are thus faced with a difference in counting efficiency by 8 orders of magnitude. The present work concentrates on the development and investigation of a novel technique for increasing the efficiency in spin-resolved electron spectroscopy by multichannel detection. The spin detector was integrated in a μ-metal shielded UHV-chamber and mounted behind a conventional hemispherical analyzer. The electrostatic lens system's geometry was determined by electron-optical simulations. The basic concept is the k parallel -conserving elastic scattering of the (0,0)-beam on a W(100) scattering crystal under 45 impact angle. It could be demonstrated that app. 960 data points (15 energy and 64 angular points) could be displayed simultaneously on a delayline detector in an energy interval of ≅3 eV. This leads to a two-dimensional figure of merit of FoM2D=1.7. Compared to conventional spin detectors, the new type is thus characterized by a gain in efficiency of 4 orders of magnitude. The operational reliability of the new spin polarimeter could be proven by measurements with a Fe/MgO(100) and O p(1 x 1)/Fe(100)-sample, where results from the literature were reproduced with strongly decreased measuring time. Due to the high intensity it becomes possible, to investigate strongly reactive samples in a short time. This advantage

  11. New data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer

    International Nuclear Information System (INIS)

    This paper describes a new data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer at the Research Center for Nuclear Physics (RCNP) in Osaka, Japan. Data are acquired by a Creative Electronic Systems (CES) Starburst, which is a CAMAC auxiliary crate controller equipped with a Digital Equipment Corporation (DEC) J11 microprocessor., The data on the Starburst are transferred to a VME single-board computer. A VME reflective memory module broadcasts the data to other systems through a fiber-optic link. A data transfer rate of 2.0 Mbytes/s between VME modules has been achieved by reflective memories. This rate includes the overhead of buffer management. The overall transfer rate, however, is limited by the performance of the Starburst to about 160 Kbytes/s at maximum. In order to further improve the system performance, the authors developed a new readout module called the Rapid Data Transfer Module (RDTM). RDTM's transfer data from LeCroy PCOS III's or 4298's, and FERA/FERET's directly to CES 8170 High Speed Memories (HSM) in VME crates. The data transfer rate of the RDTM from PCOS III's to the HSM is about 4 Mbytes/s

  12. The imaging properties of the Gas Pixel Detector as a focal plane polarimeter

    CERN Document Server

    Fabiani, S; Del Monte, E; Muleri, F; Soffitta, P; Rubini, A; Bellazzini, R; Brez, A; de Ruvo, L; Minuti, M; Pinchera, M; Sgrò, C; Spandre, G; Spiga, D; Tagliaferri, G; Pareschi, G; Basso, S; Citterio, O; Burwitz, V; Burkert, W; Menz, B; Hartner, G

    2014-01-01

    X-rays are particularly suited to probe the physics of extreme objects. However, despite the enormous improvements of X-ray Astronomy in imaging, spectroscopy and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as an instrument candidate to fill the gap of more than thirty years of lack of measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time and the polarization angle of every single photon, allows to perform polarimetry of subsets of data singled out from the spectrum, the light curve or the image of source. The GPD has an intrinsic very fine imaging capability and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray test facility of the Max-Planck-Institut f\\"ur extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it to a JET-X optics module wit...

  13. The Primordial Inflation Explorer (PIXIE): A Nulling Polarimeter for Cosmic Microwave Background Observations

    Science.gov (United States)

    Kogut, Alan J.; Fixsen, D. J.; Chuss, D. T.; Dotson, J.; Dwek, E.; Halpern, M.; Hinshaw, G. F.; Meyer, S. M.; Moseley, S. H.; Seiffert, M. D.; Spergel, D. N.; Wollack, E. J.

    2011-01-01

    The Primordial Inflation Explorer (PIXIE) is a concept for an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. The instrument consists of a polarizing Michelson interferometer configured as a nulling polarimeter to measure the difference spectrum between orthogonal linear polarizations from two co-aligned beams. Either input can view the sky or a temperature-controlled absolute reference blackbody calibrator. Rhe proposed instrument can map the absolute intensity and linear polarization (Stokes I, Q, and U parameters) over the full sky in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded optics provide background-limited sensitivity using only 4 detectors, while the highly symmetric design and multiple signal modulations provide robust rejection of potential systematic errors. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy.

  14. The Primordial Inflation Explorer (PIXIE): a nulling polarimeter for cosmic microwave background observations

    International Nuclear Information System (INIS)

    The Primordial Inflation Explorer (PIXIE) is a concept for an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. The instrument consists of a polarizing Michelson interferometer configured as a nulling polarimeter to measure the difference spectrum between orthogonal linear polarizations from two co-aligned beams. Either input can view the sky or a temperature-controlled absolute reference blackbody calibrator. Rhe proposed instrument can map the absolute intensity and linear polarization (Stokes I, Q, and U parameters) over the full sky in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 μm wavelength). Multi-moded optics provide background-limited sensitivity using only 4 detectors, while the highly symmetric design and multiple signal modulations provide robust rejection of potential systematic errors. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r −3 at 5 standard deviations. The rich PIXIE data set can also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy

  15. Demonstration of a snapshot full-Stokes division-of-aperture imaging polarimeter using Wollaston prism array

    Science.gov (United States)

    Mu, Tingkui; Zhang, Chunmin; Liang, Rongguang

    2015-12-01

    A snapshot full-Stokes division-of-aperture imaging polarimeter using a Wollaston prism array (WPA) is theoretically described and experimentally demonstrated. Two-dimensional spatial distributions of six polarization eigenstates, linear (0°, 90°, 45°, 135°), and left and right circular polarization states, are identified and separated by the WPA simultaneously and projected onto the six portions of a single focal-plane array by a lens array. The conditions of the measurement matrix formed by the six polarization modulation channels are naturally superior for immunity to Gaussian and Poisson noise. The unique properties of the WPA, such as its high extinction ratio, optical efficiency and transmittance, can further ensure the achievement of immunity. The snapshot principle and the conditions of the measurement matrix are discussed. A proof-of-concept system using a complementary metal oxide semiconductor (CMOS) sensor for visible light is built and validated using laboratory and outdoor measurements.

  16. The Effects of Improper Lighting on Professional Astronomical Observations

    CERN Document Server

    Patat, F

    2010-01-01

    Europe and a number of countries in the world are investing significant amounts of public money to operate and maintain large, ground-based astronomical facilities. Even larger projects are under development to observe the faintest and most remote astrophysical sources in the universe. As of today, on the planet there are very few sites that satisfy all the demanding criteria for such sensitive and expensive equipment, including a low level of light pollution. Because of the uncontrolled growth of incorrect illumination, even these protected and usually remote sites are at risk. Although the reasons for intelligent lighting reside in energy saving and environmental effects, the impact on scientific research cannot be neglected or underestimated, because of its high cultural value for the progress of the whole mankind. After setting the stage, in this paper I review the effects of improper lighting on professional optical and near-UV astronomical data, and discuss the possible solutions to both preserve the ni...

  17. Astronomical observation tasks short-term scheduling using PDDS algorithm

    Science.gov (United States)

    Kornilov, M. V.

    2016-07-01

    A concept of the ground-based optical astronomical observation efficiency is considered in this paper. We believe that a telescope efficiency can be increased by properly allocating observation tasks with respect to the current environment state and probability to obtain the data with required properties under the current conditions. An online observations scheduling is assumed to be an essential part for raising the efficiency. The short-term online scheduling is treated as the discrete optimisation problems which are stated using several abstraction levels. The optimisation problems are solved using the parallel depth-bounded discrepancy search (PDDS) algorithm by Moisan et al. (2014). Some aspects of the algorithm performance are discussed. The presented algorithm is a core of open-source chelyabinsk C++ library which is planned to be used at 2.5 m telescope of Sternberg Astronomical Institute of Lomonosov Moscow State University.

  18. Analysis of AGS polarimeter data at G gamma=7.5.

    CERN Document Server

    Huang, H; Spinka, H M; Underwood, D G

    2003-01-01

    Data were collected with the AGS internal polarimeter at G gamma = 7.5 during the recent FY02 polarized proton run. The addition of new forward scintillation counters permitted an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized, and the polarization measured at G gamma = 7.5 is compared to that at 200 MeV.

  19. Advances in infrared and imaging fibres for astronomical instrumentation

    CERN Document Server

    Haynes, R; Marcel, J; Jovanovic, N; Haynes, Roger; Namara, Pam Mc; Marcel, Jackie; Jovanovic, Nemanja

    2006-01-01

    Optical fibres have already played a huge part in ground based astronomical instrumentation, however, with the revolution in photonics currently taking place new fibre technologies and integrated optical devices are likely to have a profound impact on the way we manipulate light in the future. The Anglo-Australian Observatory, along with partners at the Optical Fibre Technology Centre of the University of Sydney, is investigating some of the developing technologies as part of our Astrophotonics programme. In this paper we discuss the advances that have been made with infrared transmitting fibre, both conventional and microstructured, in particular those based on flouride glasses. Flouride glasses have a particularly wide transparent region from the UV through to around 7um, whereas silica fibres, commonly used in astronomy, only transmit out to about 2um. We discuss the impact of advances in fibre manufacture that have greatly improved the optical, chemical resistance and physical properties of the flouride f...

  20. Christopher Clavius astronomer and mathematician

    CERN Document Server

    Sigismondi, Costantino

    2012-01-01

    The Jesuit scientist Christopher Clavius (1538-1612) has been the most influential teacher of the renaissance. His contributions to algebra, geometry, astronomy and cartography are enormous. He paved the way, with his texts and his teaching for 40 years in the the Collegio Romano, to the development of these sciences and their fruitful spread all around the World, along the commercial paths of Portugal, which become also the missionary paths for the Jesuits. The books of Clavius were translated into Chinese, by one of his students Matteo Ricci "Li Madou" (1562-1610), and his influence for the development of science in China was crucial. The Jesuits become skilled astronomers, cartographers and mathematicians thanks to the example and the impulse given by Clavius. This success was possible also thanks to the contribution of Clavius in the definition of the Ratio Studiorum, the program of studies, in the Jesuit colleges, so influential for the whole history of modern Europe and all western World.

  1. IAU Public Astronomical Organisations Network

    Science.gov (United States)

    Canas, Lina; Cheung, Sze Leung

    2015-08-01

    The Office for Astronomy Outreach has devoted intensive means to create and support a global network of public astronomical organisations around the world. Focused on bringing established and newly formed amateur astronomy organizations together, providing communications channels and platforms for disseminating news to the global community and the sharing of best practices and resources among these associations around the world. In establishing the importance that these organizations have for the dissemination of activities globally and acting as key participants in IAU various campaigns social media has played a key role in keeping this network engaged and connected. Here we discuss the implementation process of maintaining this extensive network, the processing and gathering of information and the interactions between local active members at a national and international level.

  2. Ancient Astronomical Monuments of Athens

    Science.gov (United States)

    Theodossiou, E.; Manimanis, V. N.

    2010-07-01

    In this work, four ancient monuments of astronomical significance found in Athens and still kept in the same city in good condition are presented. The first one is the conical sundial on the southern slope of the Acropolis. The second one is the Tower of the Winds and its vertical sundials in the Roman Forum of Athens, a small octagonal marble tower with sundials on all 8 of its sides, plus a water-clock inside the tower. The third monument-instrument is the ancient clepsydra of Athens, one of the findings from the Ancient Agora of Athens, a unique water-clock dated from 400 B.C. Finally, the fourth one is the carved ancient Athenian calendar over the main entrance of the small Byzantine temple of the 8th Century, St. Eleftherios, located to the south of the temple of the Annunciation of Virgin Mary, the modern Cathedral of the city of Athens.

  3. Astronomical arguments in Newton's Chronology

    CERN Document Server

    Naze, Yael

    2012-01-01

    In his Chronology, Newton uses astronomical "evidence" to support its extreme rejuvenation of ancient times. These elements, having a scientific varnish, provide some credibility to the work. They have been fiercely debated for a century, with a gradual undermining of Newton's assumptions. However, this has not dented the prestige of the English scientist. ----- Dans sa Chronologie, Newton utilise des "preuves" astronomiques pour appuyer son rajeunissement extreme des epoques anciennes. Ces elements, au vernis scientifique, donnent une credibilite certaine a l'ensemble. Ils ont donc ete aprement discutes, les debats sapant petit a petit les hypotheses du savant anglais pour finalement porter un coup mortel a l'ensemble. Cela n'a toutefois pas entame le prestige du savant anglais.

  4. Old Star's "Rebirth" Gives Astronomers Surprises

    Science.gov (United States)

    2005-04-01

    Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope are taking advantage of a once-in-a-lifetime opportunity to watch an old star suddenly stir back into new activity after coming to the end of its normal life. Their surprising results have forced them to change their ideas of how such an old, white dwarf star can re-ignite its nuclear furnace for one final blast of energy. Sakurai's Object Radio/Optical Images of Sakurai's Object: Color image shows nebula ejected thousands of years ago. Contours indicate radio emission. Inset is Hubble Space Telescope image, with contours indicating radio emission; this inset shows just the central part of the region. CREDIT: Hajduk et al., NRAO/AUI/NSF, ESO, StSci, NASA Computer simulations had predicted a series of events that would follow such a re-ignition of fusion reactions, but the star didn't follow the script -- events moved 100 times more quickly than the simulations predicted. "We've now produced a new theoretical model of how this process works, and the VLA observations have provided the first evidence supporting our new model," said Albert Zijlstra, of the University of Manchester in the United Kingdom. Zijlstra and his colleagues presented their findings in the April 8 issue of the journal Science. The astronomers studied a star known as V4334 Sgr, in the constellation Sagittarius. It is better known as "Sakurai's Object," after Japanese amateur astronomer Yukio Sakurai, who discovered it on February 20, 1996, when it suddenly burst into new brightness. At first, astronomers thought the outburst was a common nova explosion, but further study showed that Sakurai's Object was anything but common. The star is an old white dwarf that had run out of hydrogen fuel for nuclear fusion reactions in its core. Astronomers believe that some such stars can undergo a final burst of fusion in a shell of helium that surrounds a core of heavier nuclei such as carbon and oxygen. However, the

  5. Astronomical Data in Undergraduate courses

    Science.gov (United States)

    Clarkson, William I.; Swift, Carrie; Hughes, Kelli; Burke, Christopher J. F.; Burgess, Colin C.; Elrod, Aunna V.; Howard, Brittany; Stahl, Lucas; Matzke, David; Bord, Donald J.

    2016-06-01

    We present status and plans for our ongoing efforts to develop data analysis and problem-solving skills through Undergraduate Astronomy instruction. While our initiatives were developed with UM-Dearborn’s student body primarily in mind, they should be applicable for a wide range of institution and of student demographics. We focus here on two strands of our effort.Firstly, students in our Introductory Astronomy (ASTR 130) general-education course now perform several “Data Investigations”, in which they interrogate the Hubble Legacy Archive to illustrate important course concepts. This was motivated in part by the realization that typical public data archives now include tools to interrogate the observations that are sufficiently accessible that introductory astronomy students can use them to perform real science, albeit mostly at a descriptive level. We are continuing to refine these investigations, and, most importantly, to critically assess their effectiveness in terms of the student learning outcomes we wish to achieve. This work is supported by grant HST-EO-13758, provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.Secondly, at the advanced-undergraduate level, students taking courses in our Astronomy minor are encouraged to gain early experience in techniques of astronomical observation and analysis that are used by professionals. We present two example projects from the Fall 2015 iteration of our upper-division course ASTR330 (The Cosmic Distance Ladder), one involving Solar System measurements, the second producing calibrated aperture photometry. For both projects students conducted, analysed, and interpreted observations using our 0.4m campus telescope, and used many of the same analysis tools as professional astronomers. This work is supported partly from a Research Initiation and Seed grant from the

  6. Coronagraphic demonstration experiment using aluminum mirrors for space infrared astronomical observations

    CERN Document Server

    Oseki, Shinji; Ishihara, Daisuke; Enya, Keigo; Haze, Kanae; Kotani, Takayuki; Kaneda, Hidehiro; Nishiyama, Miho; Abe, Lyu; Yamamuro, Tomoyasu

    2015-01-01

    For future space infrared astronomical coronagraphy, we perform experimental studies on the application of aluminum mirrors to a coronagraph. Cooled reflective optics is required for broad-band mid-infrared observations in space, while high-precision optics is required for coronagraphy. For the coronagraph instrument originally proposed for the next-generation infrared astronomical satellite project SPICA (SCI: SPICA Coronagraph Instrument), we fabricated and evaluated the optics consisting of high-precision aluminum off-axis mirrors with diamond-turned surfaces, and conducted a coronagraphic demonstration experiment using the optics with a coronagraph mask. We first measured the wave front errors (WFEs) of the aluminum mirrors with a He-Ne Fizeau interferometer to confirm that the power spectral densities of the WFEs satisfy the SCI requirements. Then we integrated the mirrors into an optical system and evaluated the overall performance of the system. As a result, we estimate the total WFE of the optics to b...

  7. THE IMAGING PROPERTIES OF THE GAS PIXEL DETECTOR AS A FOCAL PLANE POLARIMETER

    Energy Technology Data Exchange (ETDEWEB)

    Fabiani, S.; Costa, E.; Del Monte, E.; Muleri, F.; Soffitta, P.; Rubini, A. [INAF-IAPS, via del Fosso del Cavaliere 100, I-00133 Roma (Italy); Bellazzini, R.; Brez, A.; De Ruvo, L.; Minuti, M.; Pinchera, M.; Sgró, C.; Spandre, G. [INFN Sezione di Pisa, Largo B. Pontecorvo, 3, I-56127 Pisa (Italy); Spiga, D.; Tagliaferri, G.; Pareschi, G.; Basso, S.; Citterio, O. [INAF-Osservatorio Astronomico di Brera, via Brera 28, I-20121 Milano (Italy); Burwitz, V.; Burkert, W., E-mail: sergio.fabiani@iaps.inaf.it [Max-Planck-Institut für extraterrestrische Physik, Gautinger Str. 45, D-82061 Neuired (Germany); and others

    2014-06-01

    X-rays are particularly suited to probing the physics of extreme objects. However, despite the enormous improvements of X-ray astronomy in imaging, spectroscopy, and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as a candidate instrument to fill the gap created by more than 30 yr without measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time, and the polarization angle of every single photon, it allows us to perform polarimetry of subsets of data singled out from the spectrum, the light curve, or an image of the source. The GPD has an intrinsic, very fine imaging capability, and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray testing facility of the Max-Planck-Institut für extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it with a JET-X optics module with a focal length of 3.5 m and an angular resolution of 18 arcsec at 4.5 keV. This configuration was proposed in 2012 aboard the X-ray Imaging Polarimetry Explorer (XIPE) in response to the ESA call for a small mission. We derived the imaging and polarimetric performance for extended sources like pulsar wind nebulae and supernova remnants as case studies for the XIPE configuration and also discuss possible improvements by coupling the detector with advanced optics that have a finer angular resolution and larger effective areas to study extended objects with more detail.

  8. The Imaging Properties of the Gas Pixel Detector as a Focal Plane Polarimeter

    Science.gov (United States)

    Fabiani, S.; Costa, E.; Del Monte, E.; Muleri, F.; Soffitta, P.; Rubini, A.; Bellazzini, R.; Brez, A.; de Ruvo, L.; Minuti, M.; Pinchera, M.; Sgró, C.; Spandre, G.; Spiga, D.; Tagliaferri, G.; Pareschi, G.; Basso, S.; Citterio, O.; Burwitz, V.; Burkert, W.; Menz, B.; Hartner, G.

    2014-06-01

    X-rays are particularly suited to probing the physics of extreme objects. However, despite the enormous improvements of X-ray astronomy in imaging, spectroscopy, and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as a candidate instrument to fill the gap created by more than 30 yr without measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time, and the polarization angle of every single photon, it allows us to perform polarimetry of subsets of data singled out from the spectrum, the light curve, or an image of the source. The GPD has an intrinsic, very fine imaging capability, and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray testing facility of the Max-Planck-Institut für extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it with a JET-X optics module with a focal length of 3.5 m and an angular resolution of 18 arcsec at 4.5 keV. This configuration was proposed in 2012 aboard the X-ray Imaging Polarimetry Explorer (XIPE) in response to the ESA call for a small mission. We derived the imaging and polarimetric performance for extended sources like pulsar wind nebulae and supernova remnants as case studies for the XIPE configuration and also discuss possible improvements by coupling the detector with advanced optics that have a finer angular resolution and larger effective areas to study extended objects with more detail.

  9. A SURVEY OF ASTRONOMICAL RESEARCH: A BASELINE FOR ASTRONOMICAL DEVELOPMENT

    International Nuclear Information System (INIS)

    Measuring scientific development is a difficult task. Different metrics have been put forward to evaluate scientific development; in this paper we explore a metric that uses the number of peer-reviewed, and when available non-peer-reviewed, research articles as an indicator of development in the field of astronomy. We analyzed the available publication record, using the Smithsonian Astrophysical Observatory/NASA Astrophysics Database System, by country affiliation in the time span between 1950 and 2011 for countries with a gross national income of less than 14,365 USD in 2010. This represents 149 countries. We propose that this metric identifies countries in ''astronomical development'' with a culture of research publishing. We also propose that for a country to develop in astronomy, it should invest in outside expert visits, send its staff abroad to study, and establish a culture of scientific publishing. Furthermore, we propose that this paper may be used as a baseline to measure the success of major international projects, such as the International Year of Astronomy 2009

  10. A Survey of Astronomical Research: A Baseline for Astronomical Development

    Science.gov (United States)

    Ribeiro, V. A. R. M.; Russo, P.; Cárdenas-Avendaño, A.

    2013-12-01

    Measuring scientific development is a difficult task. Different metrics have been put forward to evaluate scientific development; in this paper we explore a metric that uses the number of peer-reviewed, and when available non-peer-reviewed, research articles as an indicator of development in the field of astronomy. We analyzed the available publication record, using the Smithsonian Astrophysical Observatory/NASA Astrophysics Database System, by country affiliation in the time span between 1950 and 2011 for countries with a gross national income of less than 14,365 USD in 2010. This represents 149 countries. We propose that this metric identifies countries in "astronomical development" with a culture of research publishing. We also propose that for a country to develop in astronomy, it should invest in outside expert visits, send its staff abroad to study, and establish a culture of scientific publishing. Furthermore, we propose that this paper may be used as a baseline to measure the success of major international projects, such as the International Year of Astronomy 2009.

  11. Astronomical Polarimetry : new concepts, new instruments, new measurements & observations

    NARCIS (Netherlands)

    Snik, F.

    2009-01-01

    All astronomical sources are polarized to some degree. Polarimetry is therefore a powerful astronomical technique. It furnishes unique diagnostics of e.g. magnetic fields and scattering media. This thesis presents new polarimetric concepts, instruments, and measurements targeting astronomical scienc

  12. Young Galaxy's Magnetism Surprises Astronomers

    Science.gov (United States)

    2008-10-01

    Astronomers have made the first direct measurement of the magnetic field in a young, distant galaxy, and the result is a big surprise. Looking at a faraway protogalaxy seen as it was 6.5 billion years ago, the scientists measured a magnetic field at least 10 times stronger than that of our own Milky Way. They had expected just the opposite. The GBT Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF The scientists made the discovery using the National Science Foundation's ultra-sensitive Robert C. Byrd Green Bank Telescope (GBT) in West Virginia. "This new measurement indicates that magnetic fields may play a more important role in the formation and evolution of galaxies than we have realized," said Arthur Wolfe, of the University of California-San Diego (UCSD). At its great distance, the protogalaxy is seen as it was when the Universe was about half its current age. According to the leading theory, cosmic magnetic fields are generated by the dynamos of rotating galaxies -- a process that would produce stronger fields with the passage of time. In this scenario, the magnetic fields should be weaker in the earlier Universe, not stronger. The new, direct magnetic-field measurement comes on the heels of a July report by Swiss and American astronomers who made indirect measurements that also implied strong magnetic fields in the early Universe. "Our results present a challenge to the dynamo model, but they do not rule it out," Wolfe said. There are other possible explanations for the strong magnetic field seen in the one protogalaxy Wolfe's team studied. "We may be seeing the field close to the central region of a massive galaxy, and we know such fields are stronger toward the centers of nearby galaxies. Also, the field we see may have been amplified by a shock wave caused by the collision of two galaxies," he said. The protogalaxy studied with the GBT, called DLA-3C286, consists of gas with little or no star formation occurring in it. The astronomers suspect that

  13. Automatic astronomical coordinate determination using digital zenith cameras

    Directory of Open Access Journals (Sweden)

    S Farzaneh

    2009-12-01

    Full Text Available Celestial positioning has been used for navigation purposes for many years. Stars as the extra-terrestrial benchmarks provide unique opportunity in absolute point positioning. However, astronomical field data acquisition and data processing of the collected data is very time-consuming. The advent of the Global Positioning System (GPS nearly made the celestial positioning system obsolete. The new satellite-based positioning system has been very popular since it is very efficient and convenient for many daily life applications. Nevertheless, the celestial positioning method is never replaced by satellite-based positioning in absolute point positioning sense. The invention of electro-optical devices at the beginning of the 21st century was really a rebirth in geodetic astronomy. Today, the digital cameras with relatively high geometric and radiometric accuracy has opened a new insight in satellite attitude determination and the study of the Earth's surface geometry and physics of its interior, i.e., computation of astronomical coordinates and the vertical deflection components. This method or the so-called astrogeodetic vision-based method help us to determine astronomical coordinates with an accuracy better than 0.1 arc second. The theoretical background, an innovative transformation approach and the preliminary numerical results are addressed in this paper.

  14. Promotion Method of the Mission Concerning an Astronomical Observation

    Science.gov (United States)

    Okuda, Haruyuki

    1996-01-01

    Astronomical observation from space station can utilize big resource and there are possibilities of repairing parts and instruments. On the other hand, there are drawbacks such as strong limitation to the observing posture, difficulty in precise pointing and reduction of optical system function due to exhaust emission contamination. From these point of view, the following mission are listed as the candidate: (1) whole sky monitor observation by X rays and gamma rays; (2) high energy cosmic rays observation; (3) sun observation; and (4) cosmic dust experiment. The space station plan are not only big but also worldwide international cooperation work. So there are still many factors not cleared yet.

  15. Tuneable Heterodyne Infrared Spectrometer for atmospheric and astronomical studies.

    Science.gov (United States)

    Sonnabend, Guido; Wirtz, Daniel; Schmülling, Frank; Schieder, Rudolf

    2002-05-20

    The transportable setup of the Cologne Tuneable Heterodyne Infrared Spectrometer (THIS) is presented. Frequency tuneability over a wide range provided by the use of tuneable diode lasers as local oscillators (LO) allows a variety of molecules in the mid-infrared to be observed. Longtime integration, which is essential for astronomical observations, is possible owing to tight frequency control of the LO with optical feedback from an external cavity. THIS is developed to fly on the Stratospheric Observatory for Infrared Astronomy beginning in 2006 but can also be used on different types of ground-based telescopes.

  16. Virtual Observatory for Astronomers: Where Are We Now?

    CERN Document Server

    Chilingarian, Igor

    2009-01-01

    After several years of intensive technological development Virtual Observatory resources have reached a level of maturity sufficient for their routine scientific exploitation. The Virtual Observatory is starting to be used by astronomers in a transparent way. In this article I will review several research projects making use of the VO at different levels of importance. I will present two projects going further than data mining: (1) studies of environmental effects on galaxy evolution, where VO resources and services are used in connection with dedicated observations using a large telescope and numerical simulations, and (2) a study of optical and near-infrared colours of nearby galaxies complemented by the spectroscopic data.

  17. Virtual Observatory for Astronomers: Where Are We Now?

    Science.gov (United States)

    Chilingarian, I. V.

    2009-07-01

    After several years of intensive technological development Virtual Observatory resources have reached a level of maturity sufficient for their routine scientific exploitation. The Virtual Observatory is starting to be used by astronomers in a transparent way. In this article I will review several research projects making use of the VO at different levels of importance. I will present two projects going further than data mining: (1) studies of environmental effects on galaxy evolution, where VO resources and services are used in connection with dedicated observations using a large telescope and numerical simulations, and (2) a study of optical and near-infrared colours of nearby galaxies complemented by the spectroscopic data.

  18. Training telescope operators and support astronomers at Paranal

    CERN Document Server

    Boffin, Henri M J; Anderson, Joe; Pino, Andres; de Wit, Willem-Jan; Girard, Julien H V

    2016-01-01

    The operations model of the Paranal Observatory relies on the work of efficient staff to carry out all the daytime and nighttime tasks. This is highly dependent on adequate training. The Paranal Science Operations department (PSO) has a training group that devises a well-defined and continuously evolving training plan for new staff, in addition to broadening and reinforcing courses for the whole department. This paper presents the training activities for and by PSO, including recent astronomical and quality control training for operators, as well as adaptive optics and interferometry training of all staff. We also present some future plans.

  19. Astronomical Knowledge in Holy Books

    Science.gov (United States)

    Farmanyan, Sona V.; Mickaelian, Areg M.

    2015-08-01

    We investigate religious myths related to astronomy from different cultures in an attempt to identify common subjects and characteristics. The paper focuses on astronomy in religion. The initial review covers records from Holy books about sky related superstitious beliefs and cosmological understanding. The purpose of this study is to introduce sky related religious and national traditions (particularly based on different calendars; Solar or Lunar). We carried out a comparative study of astronomical issues contained in a number of Holy books: Ancient Egyptian Religion (Pyramid Texts), Zoroastrianism (Avesta), Hinduism (Vedas), Buddhism (Tipitaka), Confucianism (Five Classics), Sikhism (Guru Granth Sahib), Christianity (Bible), Islam (Quran), Druidism (Mabinogion) and Maya Religion (Popol Vuh). These books include various information on the creation of the Universe, Sun and Moon, the age of the Universe, Cosmic sizes, understanding about the planets, stars, Milky Way and description of the Heavens in different religions. We come to the conclusion that the perception of celestial objects varies from culture to culture, and from religion to religion and preastronomical views had a significant impact on humankind, particularly on religious diversities. We prove that Astronomy is the basis of cultures, and that national identity and mythology and religion were formed due to the special understanding of celestial objects.

  20. VEGAS: VErsatile GBT Astronomical Spectrometer

    Science.gov (United States)

    Bussa, Srikanth; VEGAS Development Team

    2012-01-01

    The National Science Foundation Advanced Technologies and Instrumentation (NSF-ATI) program is funding a new spectrometer backend for the Green Bank Telescope (GBT). This spectrometer is being built by the CICADA collaboration - collaboration between the National Radio Astronomy Observatory (NRAO) and the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California Berkeley.The backend is named as VErsatile GBT Astronomical Spectrometer (VEGAS) and will replace the capabilities of the existing spectrometers. This backend supports data processing from focal plane array systems. The spectrometer will be capable of processing up to 1.25 GHz bandwidth from 8 dual polarized beams or a bandwidth up to 10 GHz from a dual polarized beam.The spectrometer will be using 8-bit analog to digital converters (ADC), which gives a better dynamic range than existing GBT spectrometers. There will be 8 tunable digital sub-bands within the 1.25 GHz bandwidth, which will enhance the capability of simultaneous observation of multiple spectral transitions. The maximum spectral dump rate to disk will be about 0.5 msec. The vastly enhanced backend capabilities will support several science projects with the GBT. The projects include mapping temperature and density structure of molecular clouds; searches for organic molecules in the interstellar medium; determination of the fundamental constants of our evolving Universe; red-shifted spectral features from galaxies across cosmic time and survey for pulsars in the extreme gravitational environment of the Galactic Center.

  1. Franklin Edward Kameny (1925-2011, Astronomer)

    Science.gov (United States)

    Wright, Jason

    2012-01-01

    Dr. Frank Kameny is best known today as one of the most important members of the gay rights movement in the United States, but he was also a PhD astronomer. In fact, it was his firing from his civil service position as astronomer for the US Army Map Service on the grounds of homosexuality that sparked his lifelong career of activism. Here, I explore some aspects of his short but interesting astronomical career and the role of the AAS in his life.

  2. Astronomical problems an introductory course in astronomy

    CERN Document Server

    Vorontsov-Vel'Yaminov, B A

    1969-01-01

    Astronomical Problems: An Introductory Course in Astronomy covers astronomical problems, together with a summary of the theory and the formula to be exercised. The book discusses the types of problems solved with the help of the celestial globe and how to solve astronomical problems. The text tackles problems on interpolation, the celestial sphere, systems of celestial coordinates, and culmination. Problems about the rising and setting of a heavenly body, precession, planetary movement, and parallax and aberration are also considered. The book presents problems about refraction, the apparent m

  3. High resolution confocal polarimeter for the living human retina

    Science.gov (United States)

    Lara, D.; Paterson, C.

    2011-09-01

    There is strong evidence that the living human retina has polarization signatures that could be linked to the presence of Glaucoma, an ocular disease that is the second cause of blindness in the western world. In a polarization sensitive ophthalmoscope, the amount of light that can be used is limited for the safety of the subject, and the return is typically a small fraction of the light used for illumination, of the order of 10-6. Furthermore, the acquisition rates have to be sufficiently fast to avoid eye-movement artifacts. The light-budget available to produce a polarization image with a scanning laser ophthalmoscope is typically in the order of 10 nW, and pixel acquisition sampling rates are of several MHz. We are currently developing an imaging instrument for vision research and clinical vision applications and aim to introduce it to the medical and clinical environment using objective methods of image quality assessment. Here we discuss the stringent imaging requirements, polarimeter design, and show high resolution polarization retinal images.

  4. Building blocks for a polarimeter-on-a-chip

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, Thomas R. [NASA/Goddard Space Flight Center, Code 553, Greenbelt, MD 20771 (United States)]. E-mail: Thomas.R.Stevenson@nasa.gov; Hsieh, W.-T. [NASA/Goddard Space Flight Center, Code 553, Greenbelt, MD 20771 (United States); Schneider, Gideon [NASA/Goddard Space Flight Center, Code 553, Greenbelt, MD 20771 (United States); Travers, Douglas [NASA/Goddard Space Flight Center, Code 553, Greenbelt, MD 20771 (United States); Cao, Nga [NASA/Goddard Space Flight Center, Code 553, Greenbelt, MD 20771 (United States); Wollack, Edward [NASA/Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Limon, Michele [NASA/Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Kogut, Alan [NASA/Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)

    2006-04-15

    For the 'Primordial Anisotropy Polarization Pathfinder Array (PAPPA)' balloon flight project, we have designed and made thin-film niobium microstrip circuits as building blocks for a 'polarimeter-on-a-chip' in which superconducting transmission lines are used to couple millimeter wave signals from planar antennas to superconducting transition edge sensor (TES) detectors. Our goal is to demonstrate technology for precision measurements of the polarization of the cosmic microwave background. To enable characterization and verification of our microstrip components, we have incorporated waveguide probes on each chip that can bring millimeter wave signals from a room temperature vector network analyzer to the superconducting circuits on the chip and back again for S-parameter measurements. We have designed a planar antenna and RF choke on the probes to efficiently couple radiation between waveguide and thin-film microstrip. To support the probe antennas in waveguides, we sculpted thin silicon cantilevers that extend from an edge of each silicon chip into a pair of waveguides within a specially designed split-block mount. This technique will allow us to make calibrated measurements at low temperatures of the velocity, impedance, and loss properties of our niobium transmission lines, the frequency response of microstrip filters, hybrid couplers, or terminations, and the performance of integrated detectors.

  5. Progress in Airborne Polarimeter Inter Comparison for the NASA Aerosols-Clouds-Ecosystems (ACE) Mission

    Science.gov (United States)

    Knobelspiesse, Kirk; Redemann, Jens

    2014-01-01

    The Aerosols-Clouds-Ecosystems (ACE) mission, recommended by the National Research Council's Decadal Survey, calls for a multi-angle, multi-spectral polarimeter devoted to observations of atmospheric aerosols and clouds. In preparation for ACE, NASA funds the deployment of airborne polarimeters, including the Airborne Multiangle SpectroPolarimeter Imager (AirMSPI), the Passive Aerosol and Cloud Suite (PACS) and the Research Scanning Polarimeter (RSP). These instruments have been operated together on NASA's ER-2 high altitude aircraft as part of field campaigns such as the POlarimeter DEfinition EXperiment (PODEX) (California, early 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, California and Texas, summer 2013). Our role in these efforts has been to serve as an assessment team performing level 1 (calibrated radiance, polarization) and level 2 (retrieved geophysical parameter) instrument intercomparisons, and to promote unified and generalized calibration, uncertainty assessment and retrieval techniques. We will present our progress in this endeavor thus far and describe upcoming research in 2015.

  6. Airborne Polarimeter Intercomparison for the NASA Aerosols-Clouds-Ecosystems (ACE) Mission

    Science.gov (United States)

    Knobelspiesse, Kirk; Redemann, Jens

    2014-01-01

    The Aerosols-Clouds-Ecosystems (ACE) mission, recommended by the National Research Council's Decadal Survey, calls for a multi-angle, multi-spectral polarimeter devoted to observations of atmospheric aerosols and clouds. In preparation for ACE, NASA funds the deployment of airborne polarimeters, including the Airborne Multi-angle SpectroPolarimeter Imager (AirMSPI), the Passive Aerosol and Cloud Suite (PACS) and the Research Scanning Polarimeter (RSP). These instruments have been operated together on NASA's ER-2 high altitude aircraft as part of field campaigns such as the POlarimeter DEfinition EXperiment (PODEX) (California, early 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, California and Texas, summer 2013). Our role in these efforts has been to serve as an assessment team performing level 1 (calibrated radiance, polarization) and level 2 (retrieved geophysical parameter) instrument intercomparisons, and to promote unified and generalized calibration, uncertainty assessment and retrieval techniques. We will present our progress in this endeavor thus far and describe upcoming research in 2015.

  7. Run05 Proton Beam Polarization Measurements by pC-Polarimeter (ver. 1.1)

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa,I.; Alekseev, I.; Bazilevsky, A.; Bravar, A.; Bunce, G.; Dhawan, S.; Eyser, K.O.; Gill, R.; Haeberli, W.; Huang, H.; Makdisi, Y.; Nass, A.; Okada, H.; Stephenson, E.; Svirida, D.N.; Wise, T.; Wood, J.; Yip, K.; Zelenski, A.

    2008-07-01

    The polarization of the proton beams [1, 2] at the Relativistic Heavy Ion Collider (RHIC)[3] RHIC ring. The H-Jet polarimeter is located at the collision point allowing measurements of absolute normalization is provided by the hydrogen polarimeter, which measures over 1 {approx} 2 another measurement rather than measuring the absolute polarization. both beams. Two identical pC-polarimeters are equipped in the yellow and blue rings, where carbon ribbon target, providing fast feedback to beam operations and experiments. The days to obtain {approx} 5% statistical uncertainty (in Run05). Thus, the operation of the carbon is measured using both an atomic beam source hydrogen gas jet (H-Jet)[4, 5] and proton-carbon polarimeters was focused on better control of relative stability between one measurement to statistical accuracy within 20 to 30 seconds using an ultra-thin (typically 6 {approx} 8 {micro}g/cm{sup 2}) the rings are separated. The pC-polarimeter measures relative polarization to a few percent.

  8. Combined retrievals of boreal forest fire aerosol properties with a polarimeter and lidar

    Directory of Open Access Journals (Sweden)

    K. Knobelspiesse

    2011-03-01

    Full Text Available Absorbing aerosols play an important, but uncertain, role in the global climate. Much of this uncertainty is due to a lack of adequate aerosol measurements. The Aerosol Polarimetery Sensor (APS, which is on the NASA Glory satellite scheduled for launch in the spring of 2011, is designed to help resolve this issue by making accurate, multi-spectral, multi-angle polarized observations. Field observations with the Research Scanning Polarimeter (RSP, the APS airborne prototype, however, have established that simultaneous retrievals of aerosol absorption and vertical distribution over bright land surfaces are quite uncertain. We test a merger of RSP and High Spectral Resolution Lidar (HSRL data with observations of boreal forest fire smoke, collected during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS. During ARCTAS, the RSP and HSRL instruments were mounted on the same aircraft, and validation data were provided by instruments on an aircraft flying a coordinated flight pattern. We found that the lidar data did indeed improve aerosol retrievals using an optimal estimation method, although not primarily because of the contraints imposed on the aerosol vertical distribution. The more useful piece of information from the HSRL was the total column aerosol optical depth, which was used to select the initial value (optimization starting point of the aerosol number concentration. When ground based sun photometer network climatologies of number concentration were used as an initial value, we found that roughly half of the retrievals had unrealistic sizes and imaginary indices, even though the retrieved spectral optical depths agreed within uncertainties to independent observations. The convergence to an unrealistic local minimum by the optimal estimator is related to the relatively low sensitivity to particles smaller than 0.1 µm at large optical thicknesses. Thus, optimization algorithms used for

  9. Astronomers find distant planet like Jupiter

    CERN Multimedia

    2003-01-01

    Astronomers searching for planetary systems like our solar system have found a planet similar to Jupiter orbiting a nearby star similar to our Sun, about 90 light-years from Earth, according to researchers (1/2 page).

  10. Longwave Imaging for Astronomical Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a compact portable longwave camera for astronomical applications. In Phase 1, we will develop and deliver the focal plane array (FPA) - a...

  11. Astronomers no longer in the dark

    CERN Multimedia

    MacMillan, L

    2002-01-01

    In a significant breakthrough, British and US astronomers have begun to pin down the most elusive material in the universe. They have made a map of dark matter - the heavy, invisible stuff that gives the galaxies their shape (1 page).

  12. Longwave Imaging for Astronomical Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a compact portable longwave camera for astronomical applications. In Phase 1, we successfully developed the eye of the camera, i.e. the focal...

  13. Astronomical data bases and retrieval systems

    Science.gov (United States)

    Mead, J. M.; Nagy, T. A.; Warren, W. H., Jr.

    1981-01-01

    The status of the development of machine-readable stellar and extragalactic data bases is summarized, including several examples of astronomical applications using these data sets. The creation of a computerized bibliographical data base for cometary research is described.

  14. Astronomers Unveiling Life's Cosmic Origins

    Science.gov (United States)

    2009-02-01

    Processes that laid the foundation for life on Earth -- star and planet formation and the production of complex organic molecules in interstellar space -- are yielding their secrets to astronomers armed with powerful new research tools, and even better tools soon will be available. Astronomers described three important developments at a symposium on the "Cosmic Cradle of Life" at the annual meeting of the American Association for the Advancement of Science in Chicago, IL. Chemistry Cycle The Cosmic Chemistry Cycle CREDIT: Bill Saxton, NRAO/AUI/NSF Full Size Image Files Chemical Cycle Graphic (above image, JPEG, 129K) Graphic With Text Blocks (JPEG, 165K) High-Res TIFF (44.2M) High-Res TIFF With Text Blocks (44.2M) In one development, a team of astrochemists released a major new resource for seeking complex interstellar molecules that are the precursors to life. The chemical data released by Anthony Remijan of the National Radio Astronomy Observatory (NRAO) and his university colleagues is part of the Prebiotic Interstellar Molecule Survey, or PRIMOS, a project studying a star-forming region near the center of our Milky Way Galaxy. PRIMOS is an effort of the National Science Foundation's Center for Chemistry of the Universe, started at the University of Virginia (UVa) in October 2008, and led by UVa Professor Brooks H. Pate. The data, produced by the NSF's Robert C. Byrd Green Bank Telescope (GBT) in West Virginia, came from more than 45 individual observations totalling more than nine GigaBytes of data and over 1.4 million individual frequency channels. Scientists can search the GBT data for specific radio frequencies, called spectral lines -- telltale "fingerprints" -- naturally emitted by molecules in interstellar space. "We've identified more than 720 spectral lines in this collection, and about 240 of those are from unknown molecules," Remijan said. He added, "We're making available to all scientists the best collection of data below 50 GHz ever produced for

  15. Publication and citation statistics for UK astronomers

    CERN Document Server

    Blustin, A J

    2007-01-01

    This article presents a survey of publication and citation statistics for 835 UK professional astronomers: the majority of academics and contract researchers within the UK astronomical community. I provide histograms of these bibliometrics for the whole sample as well as of the median values for the individual departments. I discuss the distribution of top bibliometric performers in the sample, and make some remarks on the usage of bibliometrics in a real-world assessment exercise.

  16. Astronomical Plate Archives and Binary Blazars Studies

    Indian Academy of Sciences (India)

    Rene Hudec

    2011-03-01

    There are about 3 million astronomical photographic plates around the globe, representing an important data source for various aspects of astrophysics. The main advantage is the large time coverage of 100 years or even more. Recent digitization efforts, together with the development of dedicated software, enables for the first time, effective data mining and data analyses by powerful computers with these archives. Examples of blazars proposed and/or investigated on the astronomical plates are presented and discussed.

  17. Bayesian mixture models for Poisson astronomical images

    OpenAIRE

    Guglielmetti, Fabrizia; Fischer, Rainer; Dose, Volker

    2012-01-01

    Astronomical images in the Poisson regime are typically characterized by a spatially varying cosmic background, large variety of source morphologies and intensities, data incompleteness, steep gradients in the data, and few photon counts per pixel. The Background-Source separation technique is developed with the aim to detect faint and extended sources in astronomical images characterized by Poisson statistics. The technique employs Bayesian mixture models to reliably detect the background as...

  18. Conceptual design of the tangentially viewing combined interferometer-polarimeter for ITER density measurements.

    Science.gov (United States)

    Van Zeeland, M A; Boivin, R L; Brower, D L; Carlstrom, T N; Chavez, J A; Ding, W X; Feder, R; Johnson, D; Lin, L; O'Neill, R C; Watts, C

    2013-04-01

    One of the systems planned for the measurement of electron density in ITER is a multi-channel tangentially viewing combined interferometer-polarimeter (TIP). This work discusses the current status of the design, including a preliminary optical table layout, calibration options, error sources, and performance projections based on a CO2/CO laser system. In the current design, two-color interferometry is carried out at 10.59 μm and 5.42 μm and a separate polarimetry measurement of the plasma induced Faraday effect, utilizing the rotating wave technique, is made at 10.59 μm. The inclusion of polarimetry provides an independent measure of the electron density and can also be used to correct the conventional two-color interferometer for fringe skips at all densities, up to and beyond the Greenwald limit. The system features five chords with independent first mirrors to reduce risks associated with deposition, erosion, etc., and a common first wall hole to minimize penetration sizes. Simulations of performance for a projected ITER baseline discharge show the diagnostic will function as well as, or better than, comparable existing systems for feedback density control. Calculations also show that finite temperature effects will be significant in ITER even for moderate temperature plasmas and can lead to a significant underestimate of electron density. A secondary role TIP will fulfill is that of a density fluctuation diagnostic; using a toroidal Alfvén eigenmode as an example, simulations show TIP will be extremely robust in this capacity and potentially able to resolve coherent mode fluctuations with perturbed densities as low as δn∕n ≈ 10(-5).

  19. Conceptual design of the tangentially viewing combined interferometer-polarimeter for ITER density measurements

    Energy Technology Data Exchange (ETDEWEB)

    Van Zeeland, M. A.; Boivin, R. L.; Carlstrom, T. N.; Chavez, J. A.; O' Neill, R. C. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Brower, D. L.; Ding, W. X.; Lin, L. [University of California-Los Angeles, P.O. Box 957099, Los Angeles, California 90095-7099 (United States); Feder, R.; Johnson, D. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); Watts, C. [ITER Organization, 13115 St Paul Lez Durance, Cedex (France)

    2013-04-15

    One of the systems planned for the measurement of electron density in ITER is a multi-channel tangentially viewing combined interferometer-polarimeter (TIP). This work discusses the current status of the design, including a preliminary optical table layout, calibration options, error sources, and performance projections based on a CO{sub 2}/CO laser system. In the current design, two-color interferometry is carried out at 10.59 {mu}m and 5.42 {mu}m and a separate polarimetry measurement of the plasma induced Faraday effect, utilizing the rotating wave technique, is made at 10.59 {mu}m. The inclusion of polarimetry provides an independent measure of the electron density and can also be used to correct the conventional two-color interferometer for fringe skips at all densities, up to and beyond the Greenwald limit. The system features five chords with independent first mirrors to reduce risks associated with deposition, erosion, etc., and a common first wall hole to minimize penetration sizes. Simulations of performance for a projected ITER baseline discharge show the diagnostic will function as well as, or better than, comparable existing systems for feedback density control. Calculations also show that finite temperature effects will be significant in ITER even for moderate temperature plasmas and can lead to a significant underestimate of electron density. A secondary role TIP will fulfill is that of a density fluctuation diagnostic; using a toroidal Alfven eigenmode as an example, simulations show TIP will be extremely robust in this capacity and potentially able to resolve coherent mode fluctuations with perturbed densities as low as {delta}n/n Almost-Equal-To 10{sup -5}.

  20. The RHIC p-Carbon CNI Polarimeter Upgrade For The Beam Polarization And Intensity Measurements

    International Nuclear Information System (INIS)

    Proton polarization measurements in the AGS and RHIC (Relativistic Heavy Ion Collider at the beam energies 24-250 GeV) are based on proton-carbon and proton-proton elastic scattering in the Coulomb Nuclear Interference (CNI) region. Polarimeter operation in the scanning mode also gives polarization profile and beam intensity profile (beam emittance) measurements. Bunch by bunch emittance measurement is a very powerful tool for machine setup. Presently, the polarization and beam intensity profile measurements (in both vertical and horizontal planes) are restricted by the long target switching time and possible target destruction during this complicated motion. The RHIC polarimeters were operated near the limit of the counting rate for present silicon strip detectors. The ongoing polarimeter upgrade for the 2009 run will address all these problems. The upgrade should allow significant reduction of the polarization measurement errors by making feasible the complete polarization measurements, which includes polarization profiles in both the horizontal and vertical planes.

  1. Astronomers celebrate a year of new Hubble results

    Science.gov (United States)

    1995-02-01

    to reach the telescope, had indeed passed through helium, and not only that, the helium was of just the right variety to match the established theory. Dr Jakobsen has spent more than 20 years working on this subject. His recent efforts concentrated on seeking out a quasar unobscured by clouds of hydrogen, which block the tell-tale signature of helium. His search drew him to the Space Telescope project and during the telescope's early years in orbit he studied 25 likely quasars and found one promising candidate. Dr Jacobsen then had to wait for the telescope's new optics before he could get the quality of data he needed to prove the existence of helium. "We were looking for a break in the cloud cover, so to speak," the astronomer said. "We had a tantalising glimpse of the quasar with the aberrated telescope but it was only after we fixed it that we could really get a clear answer. One of the first things that we did once we had the corrective optics in place was look at this object and it was exactly as we'd hoped." Getting the Universe to measure up When it comes to studying the expansion of the Universe, however, the telescope has raised morn; questions than answers. By determining how fast the Universe is expanding astronomers will be able to calculate its age and size. It may then become possible to discover what is the ultimate fate of the Universe; will it simply continue to expand until it evaporates? Will the expansion come to a complete stop? Or will the Universe stop expanding, start contracting and end in a "big crunch"? The rate at which the Universe expands is known as the Hubble Constant or H0. To measure this value, astronomers need to calculate how far away a galaxy is and how fast it is moving away from us. The former is difficult to determine because reliable distance indicators, sometimes known as "cosmic yardsticks ", such as variable stars and supernovae, must be found in the galaxies. An international team of astronomers recently used the Hubble

  2. Astronomical Site in the Ukraine: Current Status and Problems of Preservation

    Science.gov (United States)

    Vavilova, I. B.; Karetnikov, V. G.; Konovalenko, A. A.; Logvinenko, O. O.; Pinigin, G. I.; Steshenko, N. V.; Tarady, V. K.; Yatskiv, Ya. S.

    The present status of optical and radio astronomical sites in Ukraine and the problems of preservation are briefly reviewed. The problems of light pollution and the influence of thechnology can be solved using scientific and engeneering methods. However the main problem of preservation is the economic one of maintaining the infrastructure.

  3. Polishers around the globe: an overview on the market of large astronomical mirrors

    Science.gov (United States)

    Döhring, Thorsten

    2014-07-01

    Astronomical mirrors are key elements in modern optical telescopes, their dimensions are usually large and their specifications are demanding. Only a limited number of skilled companies respectively institutions around the world are able to master the challenge to polish an individual astronomical mirror, especially in dimensions above one meter. This paper presents an overview on the corresponding market including a listing of polishers around the globe. Therefore valuable information is provided to the astronomical community: Polishers may use the information as a global competitor database, astronomers and project managers may get more transparency on potential suppliers, and suppliers of polishing equipment may learn about unknown potential customers in other parts of the world. An evaluation of the historical market demand on large monolithic astronomical mirrors is presented. It concluded that this is still a niche market with a typical mean rate of 1-2 mirrors per year. Polishing of such mirrors is an enabling technology with impact on the development of technical know-how, public relation, visibility and reputation of the supplier. Within a corresponding technical discussion different polishing technologies are described. In addition it is demonstrated that strategic aspects and political considerations are influencing the selection of the optical finisher.

  4. Foreground-induced biases in CMB polarimeter self-calibration

    Science.gov (United States)

    Abitbol, Maximilian H.; Hill, James; Johnson, Bradley

    2016-06-01

    Precise polarization measurements of the cosmic microwave background (CMB) require accurate knowledge of the instrument orientation relative to the sky frame used to define the cosmological Stokes parameters. Suitable celestial calibration sources that could be used to measure the polarimeter orientation angle are limited, so current experiments commonly `self-calibrate.' The self-calibration method exploits the theoretical fact that the EB and TB cross-spectra of the CMB vanish in the standard cosmological model, so any detected EB and TB signals must be due to systematic errors. However, this assumption neglects the fact that polarized Galactic foregrounds in a given portion of the sky may have non-zero EB and TB cross-spectra. If these foreground signals remain in the observations, then they will bias the self-calibrated telescope polarization angle and produce a spurious B-mode signal. In this paper, we estimate the foreground-induced bias for various instrument configurations and then expand the self-calibration formalism to account for polarized foreground signals. Assuming the EB correlation signal for dust is in the range constrained by angular power spectrum measurements from Planck at 353 GHz (scaled down to 150 GHz), then the bias is negligible for high angular resolution experiments, which have access to CMB-dominated high 'ell' modes with which to self-calibrate. Low-resolution experiments observing particularly dusty sky patches can have a bias as large as 0.5°. A miscalibration of this magnitude generates a spurious BB signal corresponding to a tensor-to-scalar ratio of approximately r ~ 2 × 10-3, within the targeted range of planned experiments.

  5. The project of installing a ZIMPOL_3 polarimeter at GREGOR in Tenerife

    Science.gov (United States)

    Bianda, M.; Ramelli, R.; Stenflo, J.; Berdyugina, S.; Gisler, D.; Defilippis, I.; Bello González, N.

    A project of collaboration between Kiepenheuer Institut für Sonnenphysik, KIS, and Istituto Ricerche Solari Locarno, IRSOL, includes the installation of a ZIMPOL_3 high resolution polarimeter at the 1.5 meter aperture solar telescope GREGOR in Tenerife. Important scientific topics are expected to be investigated, in particular in the case of events showing faint amplitude polarization signatures like scattering polarization effects, and the Hanle effect. This project has also a technical importance, this combination can be used as test bench for future polarimeters to be installed on the new generation solar telescopes.

  6. A precise in situ calibration of the RHIC H-Jet polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Poblaguev, A. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-03-05

    Two new methods of calibration of the hydrogen jet target polarimeter (H-Jet) at RHIC are discussed. First method is based on the measurement of low amplitude signal time of fast particles penetrating through detector. The second, geometry based, method employs correlation between z-coordinate of the recoil proton and its kinetic energy. Both methods can be used for in situ calibration of the H-Jet polarimeter. These two methods are compared with a traditional calibration of the H-Jet which uses α-sources.

  7. Multilayer based soft-x-ray polarimeter at MAX IV Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Grizolli, Walan; Laksman, Joakim; Hennies, Franz; Jensen, Brian Norsk; Nyholm, Ralf; Sankari, Rami, E-mail: rami.sankari@maxlab.lu.se [MAX IV Laboratory, P.O. Box 118, SE-22100 Lund (Sweden)

    2016-02-15

    A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B{sub 4}C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.

  8. Multilayer based soft-x-ray polarimeter at MAX IV Laboratory

    Science.gov (United States)

    Grizolli, Walan; Laksman, Joakim; Hennies, Franz; Jensen, Brian Norsk; Nyholm, Ralf; Sankari, Rami

    2016-02-01

    A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B4C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.

  9. Scalable Machine Learning for Massive Astronomical Datasets

    Science.gov (United States)

    Ball, Nicholas M.; Gray, A.

    2014-04-01

    We present the ability to perform data mining and machine learning operations on a catalog of half a billion astronomical objects. This is the result of the combination of robust, highly accurate machine learning algorithms with linear scalability that renders the applications of these algorithms to massive astronomical data tractable. We demonstrate the core algorithms kernel density estimation, K-means clustering, linear regression, nearest neighbors, random forest and gradient-boosted decision tree, singular value decomposition, support vector machine, and two-point correlation function. Each of these is relevant for astronomical applications such as finding novel astrophysical objects, characterizing artifacts in data, object classification (including for rare objects), object distances, finding the important features describing objects, density estimation of distributions, probabilistic quantities, and exploring the unknown structure of new data. The software, Skytree Server, runs on any UNIX-based machine, a virtual machine, or cloud-based and distributed systems including Hadoop. We have integrated it on the cloud computing system of the Canadian Astronomical Data Centre, the Canadian Advanced Network for Astronomical Research (CANFAR), creating the world's first cloud computing data mining system for astronomy. We demonstrate results showing the scaling of each of our major algorithms on large astronomical datasets, including the full 470,992,970 objects of the 2 Micron All-Sky Survey (2MASS) Point Source Catalog. We demonstrate the ability to find outliers in the full 2MASS dataset utilizing multiple methods, e.g., nearest neighbors. This is likely of particular interest to the radio astronomy community given, for example, that survey projects contain groups dedicated to this topic. 2MASS is used as a proof-of-concept dataset due to its convenience and availability. These results are of interest to any astronomical project with large and/or complex

  10. Large astronomical catalog management for telescope operations

    Science.gov (United States)

    Baruffolo, Andrea; Benacchio, Leopoldo

    1998-07-01

    Large astronomical catalogues containing from a million up to hundreds of millions records are currently available, even larger catalogues will be released in the near future. They will have an important operational role since they will be used throughout the observing cycle of next generation large telescopes, for proposal and observation preparation, telescope scheduling, selection of guide stars, etc. These large databases pose new problems for fast and general access. Solutions based on custom software or on customized versions of specific catalogues have been proposed, but the problem will benefit from a more general database approach. While traditional database technologies have proven to be inadequate for this task, new technologies are emerging, in particular that of Object Relational DBMSs, that seem to be suitable to solve the problem. In this paper we describe our experiences in experimenting with ORDBMSs for the management of large astronomical catalogues. We worked especially on the database query language and access methods. In the first field to extend the database query language capabilities with astronomical functionalities and to support typical astronomical queries.In the second, to speed up the execution of queries containing astronomical predicates.

  11. How Astronomers View Education and Public Outreach

    CERN Document Server

    Dang, Lisa

    2015-01-01

    Over the past few years, there have been a few studies on the development of an interest in science and scientists' views on public outreach. Yet, to date, there has been no global study regarding astronomers' views on these matters. Through the completion of our survey by 155 professional astronomers online and in person during the 28th International Astronomical Union General Assembly in 2012, we explored their development of and an interest for astronomy and their views on time constraints and budget restriction regarding public outreach activities. We find that astronomers develop an interest in astronomy between the ages of 4-6 but that the decision to undertake a career in astronomy often comes during late adolescence. We also discuss the claim that education and public outreach is regarded an optional task rather than a scientist's duty. Our study revealed that many astronomers think there should be a larger percentage of their research that should be invested into outreach activities, calling for a ch...

  12. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  13. Career situation of female astronomers in Germany

    CERN Document Server

    Fohlmeister, J; 10.1002/asna.201211656

    2012-01-01

    We survey the job situation of women in astronomy in Germany and of German women abroad and review indicators for their career development. Our sample includes women astronomers from all academic levels from doctoral students to professors, as well as female astronomers who have left the field. We find that networking and human support are among the most important factors for success. Experience shows that students should carefully choose their supervisor and collect practical knowledge abroad. We reflect the private situation of female German astronomers and find that prejudices are abundant, and are perceived as discriminating.We identify reasons why women are more likely than men to quit astronomy after they obtain their PhD degree. We give recommendations to young students on what to pay attention to in order to be on the successful path in astronomy.

  14. Thirteenth Joint European and National Astronomical Meeting

    CERN Document Server

    Iniesta, J C

    2006-01-01

    The book gathers the invited talks to the XIII JENAM conference, organized this time by the European Astronomical Society (EAS) and the Spanish Astronomical Society (SEA), and hosted by the Instituto de Astrofísica de Andalucía (CSIC). All branches of astrophysics are encompassed from the largest scales and cosmology to the solar system and the Sun, through the galaxies and the stars, including a section on astronomical instrumentation. Very relevant experts from all over the world speak in a single book about the most recent, exciting results from their fields in a way which is useful for both researchers in these fields and colleagues working in other disciplines. The book is accompanied by a CD-ROM including the remaining contributions of the meeting in PDF format, hence opening a wide panorama of what is going on in astrophysics nowadays.

  15. Decoding the mechanisms of Antikythera astronomical device

    CERN Document Server

    Lin, Jian-Liang

    2016-01-01

    This book presents a systematic design methodology for decoding the interior structure of the Antikythera mechanism, an astronomical device from ancient Greece. The historical background, surviving evidence and reconstructions of the mechanism are introduced, and the historical development of astronomical achievements and various astronomical instruments are investigated. Pursuing an approach based on the conceptual design of modern mechanisms and bearing in mind the standards of science and technology at the time, all feasible designs of the six lost/incomplete/unclear subsystems are synthesized as illustrated examples, and 48 feasible designs of the complete interior structure are presented. This approach provides not only a logical tool for applying modern mechanical engineering knowledge to the reconstruction of the Antikythera mechanism, but also an innovative research direction for identifying the original structures of the mechanism in the future. In short, the book offers valuable new insights for all...

  16. Making Access to Astronomical Software More Efficient

    CERN Document Server

    Grosbol, P

    2010-01-01

    Access to astronomical data through archives and VO is essential but does not solve all problems. Availability of appropriate software for analyzing the data is often equally important for the efficiency with which a researcher can publish results. A number of legacy systems (e.g. IRAF, MIDAS, Starlink, AIPS, Gipsy), as well as others now coming online are available but have very different user interfaces and may no longer be fully supported. Users may need multiple systems or stand-alone packages to complete the full analysis which introduces significant overhead. The OPTICON Network on `Future Astronomical Software Environments' and the USVAO have discussed these issues and have outlined a general architectural concept that solves many of the current problems in accessing software packages. It foresees a layered structure with clear separation of astronomical code and IT infrastructure. By relying on modern IT concepts for messaging and distributed execution, it provides full scalability from desktops to cl...

  17. Exploring a possible origin of a 14 deg y-normal spin tilt at RHIC polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-06-15

    A possible origin of a 14 deg y-normal spin n0 tilt at the polarimeter is in snake angle defects. This possible cause is investigated by scanning the snake axis angle µ, and the spin rotation angle at the snake, φ, in the vicinity of their nominal values.

  18. A Novel Spin-Light Polarimeter for the Electron Ion Collider

    CERN Document Server

    Mohanmurthy, Prajwal

    2013-01-01

    A novel precision polarimeter will go a long way in satisfying the requirements of the precision experiments being planned for a future facility such as the Electron Ion Collider. A polarimeter based on the asymmetry in the spacial distribution of the spin light component of synchrotron radiation will make for a fine addition to the existing-conventional M{\\o}ller and Compton polarimeters. The spin light polarimeter consists of a set of wriggler magnet along the beam that generate synchrotron radiation. The spacial distribution of synchrotron radiation will be measured by an ionization chamber after being collimated. The up-down spacial asymmetry in the transverse plane is used to quantify the polarization of the beam. As a part of the design process, firstly, a rough calculation was drawn out to establish the validity of such an idea. Secondly, the fringe fields of the wriggler magnet was simulated using a 2-D magnetic field simulation toolkit called Poisson Superfish, which is maintained by Los Alamos Natio...

  19. Readout system with on-board demodulation for CMB polarization experiments using coherent polarimeter arrays

    CERN Document Server

    Ishidoshiro, Koji; Higuchi, Takeo; Hasegawa, Masaya; Hazumi, Masashi; Ikeno, Masahiro; Tajima, Osamu; Tanaka, Manobu; Uchida, Tomohisa

    2011-01-01

    B-modes are special patterns in cosmic microwave background (CMB) polarization. The detection of them is a smoking-gun signature of primordial gravitational waves. The generic strategy of the CMB polarization experiments is to employ a large number of polarimeters for improving the statistics. The Q/U Imaging ExperimenT-II (QUIET-II) has been proposed to detect the B-modes using the world's largest coherent polarimeter array (2,000 channels). An unique detection technique using QUIET's polarimeters, which is a modula- tion/demodulation scheme, enables us directly extracting the polarization signal. The extracted signal is free from non- polarized components and intrinsic 1/f noise. We developed a data readout system with on-board demodulation functions for the QUIET-II experiment. We employed a "master" clock strategy. This strategy guarantees phase matching between the modulation by the polarimeters and the demodulation by ADC modules. The single master generates all carrier clocks and distributes them to ea...

  20. RHIC pC CNI Polarimeter: Status and Performance from the First Collider Run

    International Nuclear Information System (INIS)

    Polarimeters using the proton carbon elastic scattering process in Coulomb Nuclear Interference (CNI) region were installed in two RHIC rings. Polarization measurements were successfully carried out with the high energy polarized proton beams for the first polarized pp collision run. The physics principles, performance, and polarization measurements are presented

  1. RHIC PC CNI POLARIMETER:STATUS AND PERFORMANCE from THE FIRST COLLIDER RUN

    International Nuclear Information System (INIS)

    Polarimeters using the proton carbon elastic scattering process in Coulomb Nuclear Interference (CNI) region were installed in two RHIC rings. Polarization measurements were successfully carried out with the high energy polarized proton beams for the first polarized pp collision run. The physics principles, performance, and polarization measurements are presented

  2. EPOL: the exoplanet polarimeter for EPICS at the E-ELT

    NARCIS (Netherlands)

    Snik, F.; Keller, C.U.; Schmid, H. M.; Venema, L.B.; Hanenburg, H.; Jager, R.; Kasper, M.; Martinez, P.; Rigal, F.; de Juan Ovelar, M.; Rodenhuis, M.; Korkiakoski, V.A.; Min, M.; Canovas Cabrera, H.; Roelfsema, R.; Verinaud, C.; Yaitskova, N.

    2010-01-01

    EPOL is the imaging polarimeter part of EPICS (Exoplanet Imaging Camera and Spectrograph) for the 42-m E-ELT. It is based on sensitive imaging polarimetry to differentiate between linearly polarized light from exoplanets and unpolarized, scattered starlight and to characterize properties of exoplane

  3. Anomalous Post-Newtonian terms and the secular increase of the Astronomical Unit

    CERN Document Server

    Acedo, L

    2014-01-01

    In the last decade a major debate has emerged on the astrophysics community concerning the anomalous behaviour of the astronomical unit, the fundamental scale of distances in the Solar system. Several independent studies have combined radar ranging and optical data from the last four decades to come to the conclusion that the astronomical unit is increasing by several meters per century. It is abundantly clear that General Relativity cannot account for this new effect, although an still undefined angular momentum transfer mechanism could provide the simpler and more conventional explanation. Here we investigate several anomalous post-newtonian terms containing only the product of the mass and angular momentum of the Sun as well as its Schwarzschild radius in order to determine if they could explain the secular increase of the astronomical unit and the recently reported increase of Lunar eccentricity. If these anomalies are confirmed, searching for a modification of General Relativity predicting these terms co...

  4. Water-Powered Astronomical Clock Tower

    Science.gov (United States)

    Sun, Xiaochun

    The construction of water-powered astronomical instruments was a long tradition of instrument making that started in the second century AD with Zhang Heng's water-powered celestial globe. The technology reached a peak when, in the eleventh century, Su Song and his team constructed the Water-Powered Astronomical Clock Tower which combined the armillary sphere, the celestial globe, and the time-keeping mechanism into a large automatic structure. Su Song's instrument contained a mechanism for controlling the water-powered movements of its wheels that amounts to an "escapement mechanism" for a mechanical clock. A new reconstruction of the mechanism is introduced in this chapter.

  5. A Novel Semantic Software for Astronomical Concepts

    CERN Document Server

    Heydari-Malayeri, M; Petit, F Le

    2012-01-01

    We have created a new semantic tool called AstroConcepts, providing definitions of astronomical concepts present on Web pages. This tool is a Google Chrome plug-in that interrogates the Etymological Dictionary of Astronomy and Astrophysics, developed at Paris Observatory. Thanks to this tool, if one selects an astronomical concept on a web page, a pop-up window will display the definition of the available English or French terms. Another expected use of this facility could be its implementation in Virtual Observatory services.

  6. 432-μm laser's beam-waist measurement for the polarimeter / interferometer on the EAST Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z. X.; Liu, H. Q.; Jie, Y. X. [Chinese Academy of Sciences, Anhui (China); and others

    2014-10-15

    A far-infrared (FIR) polarimeter / interferometer (PI) system is under development for measurements of the current-density and the electron-density profiles in the EAST tokamak. The system will utilize three identical 432-μm CHCOOH lasers pumped by a CO{sub 2} laser. Measurements of the laser beam's waist size and position are basic works. This paper will introduce three methods with a beam profiler and several focusing optical elements. The beam profiler can be used to show the spatial energy distribution of the laser beam. The active area of the profiler is 12.4 x 12.4 mm{sup 2}. Some focusing optical elements are needed to focus the beam in order for the beam profiler to receive the entire laser beam. Two principles and three methods are used in the measurement. The first and the third methods are based on the same principle, and the second method adopts an other principle. Due to the fast and convenient measurement, although the first method is a special form of the third and it can only give the size of beam waist, it is essential to the development of the experiment and it can provide guidance for the choices of the sizes of the optical elements in the next step. A concave mirror, a high-density polyethylene (HDPE) lens and a polymethylpentene (TPX) lens are each used in the measurement process. The results of these methods are close enough for the design of PI system's optical path.

  7. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  8. Critical factors for a successful astronomical research program in a developing country

    Science.gov (United States)

    Hearnshaw, John B.

    I discuss the critical conditions for undertaking a successful research program in a developing country. There are many important factors, all or most of which have to be satisfied: funding, library holdings, computing access, Internet access (e-mail, WWW, ftp, telnet), collaboration with astronomers in developed countries, provision of proper offices for staff, supply of graduate students, access to travel for conferences, ability to publish in international journals, critical mass of researchers, access to a telescope (for observational astronomers), support from and interaction with national electronics, optics and precision engineering industries, a scientific culture backed by a national scientific academy, and lack of inter-institutional rivalry. I make a list of a total of 15 key factors and rank them in order of importance, and discuss the use of an astronomical research index (ARI) suitable for measuring the research potential of a given country or institution. I also discuss whether astronomers in developing countries in principle fare better in a university or in the environment of a government national observatory or research institution, and topics such as the effect of the cost of page charges and journal subscriptions on developing countries. Finally I present some statistics on astronomy in developing countries and relate the numbers of astronomers to the size of the economy and population in each country.

  9. The upgrade of a high dispersion spectro-polarimeter, VESPolA: new circular polarimetry mode and extremely high resolution mode

    Science.gov (United States)

    Arasaki, Takayuki; Ikeda, Yuji; Akika, Nakamichi; Kawakita, Hideyo

    2014-08-01

    VESPolA is a high dispersion spectro-polarimeter, mounted on the 1.3m Araki telescope at Koyama Astronomical Observatory of Kyoto Sangyo University. It employs an echelle type spectrograph and a non-ripple super-achromatic half wave plate, resulting in the highly polarimetric accuracy of δP circular polarimetry mode for this study, to VESPolA. We employ an alumina (Al2O3) slit as the new slit for the high resolution mode to minimize the instrumental polarization generated at the edge of the slit. However, because the slit width should be very narrow (= 35μm), it is technically difficult to realize the smooth slit without burr or chipping. We are trying the various processing methods, machining, etching, laser cutting, and so on. The circular polarimetry mode can be realized with a new non-ripple super-achromatic quarter wave plate and the high precision rotary unit, which is located just below the existing the half wave plate unit. We will finish the update within 2015 and start the science observations.

  10. ASTRONOMICAL OBSERVING SYSTEM OVER THE ELECTROMAGNETIC SPECTRUM

    Directory of Open Access Journals (Sweden)

    A. B. BHATTACHARYA,

    2010-09-01

    Full Text Available The astronomical instruments over the electromagnetic spectrum that had been brought towards perfection owing to sudden arrival of radio astronomy are outlined. Improved techniques of observations from space,in situ exploration of the solar system as well as the advent of computer technologies have directed lines of new possibilities, which have been critically examined.

  11. Astroquery: querying astronomical web forms and databases

    OpenAIRE

    Sipocz, Brigitta

    2016-01-01

    Astroquery is an Astropy affiliated package for a set of tools for querying astronomical web forms and databases. In this lightning talk I give an overview of the available services and the usage of the package including a live demo of a typical use case.

  12. Astroquery: querying astronomical web forms and databases

    Science.gov (United States)

    Sipocz, Brigitta

    2016-03-01

    Astroquery is an Astropy affiliated package for a set of tools for querying astronomical web forms and databases. In this lightning talk I give an overview of the available services and the usage of the package including a live demo of a typical use case.

  13. Astronomía en la cultura

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    La Astronomía en la Cultura es el estudio interdisciplinario a nivel global de la astronomía prehistórica, antigua y tradicional, en el marco de su contexto cultural. Esta disciplina abarca cualquier tipo de estudios o líneas de investigación en que se relacione a la astronomía con las ciencias humanas o sociales. En ella se incluyen tanto fuentes escritas, relatos orales como fuentes arqueológicas, abarcando entre otros, los siguientes temas: calendarios, observación práctica, cultos y mitos, representación simbólica de eventos, conceptos y objetos astronómicos, orientación astronómica de tumbas, templos, santuarios y centros urbanos, cosmología tradicional y la aplicación ceremonial de tradiciones astronómicas, la propia historia de la astronomía y la etnoastronomía (Krupp, 1989) (Iwaniszewski, 1994). En nuestro trabajo abordamos la historia y situación actual de esta disciplina, sus métodos y sus relaciones con otras áreas de investigación.

  14. Professional Astronomers in Service to the AAVSO

    Science.gov (United States)

    Saladyga, M.; Waagen, E. O.

    2012-06-01

    (Abstract only) Throughout its 100-year history, the American Association of Variable Star Observers (AAVSO) has welcomed professional astronomers to its membership ranks, and has encouraged their participation as organization leaders. The AAVSO has been fortunate to have over 60 distinguished professionals serve as officers (Directors, Presidents, Council), and as participants in its various scientific and organizational committees.

  15. astLib: Tools for research astronomers

    Science.gov (United States)

    Hilton, Matt; Boada, Steven

    2016-07-01

    astLib is a set of Python modules for performing astronomical plots, some statistics, common calculations, coordinate conversions, and manipulating FITS images with World Coordinate System (WCS) information through PyWCSTools, a simple wrapping of WCSTools (ascl:1109.015).

  16. The Virtual Astronomical Observatory Users Forum

    Science.gov (United States)

    Muench, August A.; Emery Bunn, S.; Astronomical Observatory, Virtual

    2013-01-01

    We present the online forum astrobabel.com, which has the goal of being a gathering place for the collective community intelligence about astronomical computing. The audience for this forum is anyone engaged in the analysis of astronomical or planetary data, whether that data be observational or theoretical. It is a free, community driven site where discussions are formulated primarily around the "question and answer" format. Current topics on the forum range from “Is there a photometry package in Python?” to “Where are the support forums for astronomy software packages?” and “Why is my SDSS SkyQuery query missing galaxies?” The poster will detail the full scope of discussions in the forum, and provide some basic guidelines for ensuring high quality forum posts. We will highlight the ways astronomers can discover and participate in discussions. Further, we view this as an excellent opportunity to gather feedback and feature requests from AAS221 attendees. Acknowledgement: The Virtual Astronomical Observatory (VAO) is managed by the VAO, LLC, a non-profit company established as a partnership of the Associated Universities, Inc. and the Association of Universities for Research in Astronomy, Inc. The VAO is sponsored by the National Science Foundation and the National Aeronautics and Space Administration.

  17. He2-90'S APPEARANCE DECEIVES ASTRONOMERS

    Science.gov (United States)

    2002-01-01

    Astronomers using NASA's Hubble Space Telescope have stumbled upon a mysterious object that is grudgingly yielding clues to its identity. A quick glance at the Hubble picture at top shows that this celestial body, called He2-90, looks like a young, dust-enshrouded star with narrow jets of material streaming from each side. But it's not. The object is classified as a planetary nebula, the glowing remains of a dying, lightweight star. But the Hubble observations suggest that it may not fit that classification, either. The Hubble astronomers now suspect that this enigmatic object may actually be a pair of aging stars masquerading as a single youngster. One member of the duo is a bloated red giant star shedding matter from its outer layers. This matter is then gravitationally captured in a rotating, pancake-shaped accretion disk around a compact partner, which is most likely a young white dwarf (the collapsed remnant of a sun-like star). The stars cannot be seen in the Hubble images because a lane of dust obscures them. The Hubble picture at top shows a centrally bright object with jets, appearing like strings of beads, emanating from both sides of center. (The other streaks of light running diagonally from He2-90 are artificial effects of the telescope's optical system.) Each jet possesses at least six bright clumps of gas, which are speeding along at rates estimated to be at least 375,000 miles an hour (600,000 kilometers an hour). These gaseous salvos are being ejected into space about every 100 years, and may be caused by periodic instabilities in He2-90's accretion disk. The jets from very young stars behave in a similar way. Deep images taken from terrestrial observatories show each jet extending at least 100,000 astronomical units (one astronomical unit equals the Earth-Sun distance, 93 million miles). The jets' relatively modest speed implies that one member of the duo is a white dwarf. Observations by the Compton Gamma-Ray Observatory, however, discovered a

  18. Netware Environment at the Astronomical Institute of the ST. Petersburg University

    Science.gov (United States)

    Titov, V. B.

    1997-03-01

    The local network of the Astronomical Institute (AI) of the St. Petersburg State University, supported by the Netware environment, integrates several dozens of computers and provides a connection to Internet. The astronomical data, maintained at AI (Database of Radio-astronomical Catalogs -- RAC DB, Galaxies data), are accessible to all local users. Most of the data is accessible through the Internet as well. The development of RAC DB was started in 1994. At present the RAC DB consists of several dozens of well known radio astronomical catalogs and some catalogs of radio sources in galaxy clusters, produced at AI. Galaxies database, which is available at present only for the local users, includes: active galaxy nuclei data (optical polarimetric time series, optical light curves since 1967--1968), polar ring galaxies data (6-meter telescope images and rotation curves), data related to interaction of galaxies. Three access methods are available for RAC DB users: FTP-access, on-line access and access via World Wide Web.

  19. DAQ system for high energy polarimeter at the LHE, JINR: implementation based on the qdpb (data processing with branchpoints) system

    International Nuclear Information System (INIS)

    Online data acquisition (DAQ) system's implementation for the High Energy Polarimeter (HEP) at the LHE, JINR is described. HEP DAQ is based on the qdpb system. Software modules specific for such implementation (HEP data and hardware dependent) are discussed

  20. Relativistic scaling of astronomical quantities and the system of astronomical units

    OpenAIRE

    Klioner, Sergei A.

    2005-01-01

    For relativistic modelling of high-accuracy astronomical data several time scales are used: barycentric and geocentric coordinate times, TCB and TCG, as well as two additional time scales, TDB and TT, that are defined as linear functions of TCB and TCG, respectively. The paper is devoted to a concise but still detailed explanation of the reasons and the implications of the relativistic scalings of astronomical quantities induced by the time scales TDB and TT. We consequently distinguish betwe...

  1. A new photoelectron imager for X-ray astronomical polarimetry

    International Nuclear Information System (INIS)

    A new photoelectron imager for X-ray astronomical polarimetry (PIAP) has been developed and tested at the Frascati (Rome, Italy) National Laboratories of National Institute of Nuclear Physics (LNF-INFN). A charge-coupled device (CCD) is placed on one of the two conjugate foci of a Cassegrain reflective optics onto which are focused UV photons emitted by means of gas scintillation. This X-ray detector has been built to image the angular distribution of the photoelectron tracks, whose anisotropy measures the X-ray polarization. First tests, performed by using mixtures based on argon gas and benzene at low pressure, show events which are candidate tracks of photoelectrons and Auger electrons produced by a 55Fe source

  2. A new photoelectron imager for X-ray astronomical polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    La Monaca, A. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Costa, E; Soffitta, P.; Di Persio, G.; Manzan, M.; Martino, B.; Patria, G. [CNR, Rome (Italy). Ist. di Astrofisica Spaziale; Cappuccio, G. [CNR, Monterotondo (Italy). Ist. di Strutturistica Chimica]|[INFN, Laboratori Nazionali di Frascati, Rome (Italy); Zema, N. [CNR, Rome (Italy). Ist. di Struttura della Materia

    1998-04-01

    A new photoelectron imager for X-ray astronomical polarimetry (PIAP) has been developed and tested at the Frascati (Rome, Italy) National Laboratories of National Institute of Nuclear Physics (LNF-INFN). A charge-coupled device (CCD) is placed on one of the two conjugate foci of a Cassegrain reflective optics onto which are focused UV photons emitted by means of gas scintillation. This X-ray detector has been built to image the angular distribution of the photoelectron tracks, whose anisotropy measures the X-ray polarization. First tests, performed by using mixtures based on argon gas and benzene at low pressure, show events which are candidate tracks of photoelectrons and Auger electrons produced by a {sup 55}Fe source.

  3. Detection and Removal of Artifacts in Astronomical Images

    CERN Document Server

    Desai, Shantanu; Bertin, Emmanuel; Kummel, Martin; Wetzstein, Michael

    2016-01-01

    Astronomical images from optical photometric surveys are typically contaminated with transient artifacts such as cosmic rays, satellite trails and scattered light. We have developed and tested an algorithm that removes these artifacts using a deep, artifact free, static sky coadd image built up through the median combination of point spread function (PSF) homogenized, overlapping single epoch images. Transient artifacts are detected and masked in each single epoch image through comparison with an artifact free, PSF-matched simulated image that is constructed using the PSF-corrected, model fitting catalog from the artifact free coadd image together with the position variable PSF model of the single epoch image. This approach works well not only for cleaning single epoch images with worse seeing than the PSF homogenized coadd, but also the traditionally much more challenging problem of cleaning single epoch images with better seeing. In addition to masking transient artifacts, we have developed an interpolation...

  4. Multichannel spin polarimeter for energy- and angle-dispersive photoemission measurements; Vielkanal-Spinpolarimeter fuer energie- und winkeldispersive Photoemissionsmessungen

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, Michaela

    2011-09-09

    Spin polarization measurements of free electrons remain challenging since their first realization by Mott. The relevant quantity of a spin polarimeter is its figure of merit, FoM=S{sup 2}I/I{sub 0}, with the asymmetry function S and the ratio between scattered and primary intensity I/I{sub 0}. State-of-the-art devices are based on single-channel scattering (spin-orbit or exchange interaction) which is characterized by FoM {approx_equal}10{sup -4}. On the other hand, modern hemispherical analyzers feature an efficient multichannel detection of spin-integral intensity with more than 10{sup 4} data points simultaneously. In comparison between spin-resolved and spin-integral electron spectroscopy we are thus faced with a difference in counting efficiency by 8 orders of magnitude. The present work concentrates on the development and investigation of a novel technique for increasing the efficiency in spin-resolved electron spectroscopy by multichannel detection. The spin detector was integrated in a {mu}-metal shielded UHV-chamber and mounted behind a conventional hemispherical analyzer. The electrostatic lens system's geometry was determined by electron-optical simulations. The basic concept is the k {sub parallel} -conserving elastic scattering of the (0,0)-beam on a W(100) scattering crystal under 45 impact angle. It could be demonstrated that app. 960 data points (15 energy and 64 angular points) could be displayed simultaneously on a delayline detector in an energy interval of {approx_equal}3 eV. This leads to a two-dimensional figure of merit of FoM{sub 2D}=1.7. Compared to conventional spin detectors, the new type is thus characterized by a gain in efficiency of 4 orders of magnitude. The operational reliability of the new spin polarimeter could be proven by measurements with a Fe/MgO(100) and O p(1 x 1)/Fe(100)-sample, where results from the literature were reproduced with strongly decreased measuring time. Due to the high intensity it becomes possible, to

  5. Astronomical photonics in the context of infrared interferometry and high-resolution spectroscopy

    CERN Document Server

    Labadie, Lucas; Cvetojevic, Nick; Haynes, Roger; Harris, Robert; Jovanovic, Nemanja; Lacour, Sylvestre; Martin, Guillermo; Minardi, Stefano; Perrin, Guy; Roth, Martin; Thomson, Robert R

    2016-01-01

    We review the potential of Astrophotonics, a relatively young field at the interface between photonics and astronomical instrumentation, for spectro-interferometry. We review some fundamental aspects of photonic science that drove the emer- gence of astrophotonics, and highlight the achievements in observational astrophysics. We analyze the prospects for further technological development also considering the potential synergies with other fields of physics (e.g. non-linear optics in condensed matter physics). We also stress the central role of fiber optics in routing and transporting light, delivering complex filters, or interfacing instruments and telescopes, more specifically in the context of a growing usage of adaptive optics.

  6. Division of focal plane polarimeter-based 3 × 4 Mueller matrix microscope: a potential tool for quick diagnosis of human carcinoma tissues

    Science.gov (United States)

    Chang, Jintao; He, Honghui; Wang, Ye; Huang, Yi; Li, Xianpeng; He, Chao; Liao, Ran; Zeng, Nan; Liu, Shaoxiong; Ma, Hui

    2016-05-01

    A polarization microscope is a useful tool to reveal the optical anisotropic nature of a specimen and can provide abundant microstructural information about samples. We present a division of focal plane (DoFP) polarimeter-based polarization microscope capable of simultaneously measuring both the Stokes vector and the 3×4 Mueller matrix with an optimal polarization illumination scheme. The Mueller matrix images of unstained human carcinoma tissue slices show that the m24 and m34 elements can provide important information for pathological observations. The characteristic features of the m24 and m34 elements can be enhanced by polarization staining under illumination by a circularly polarized light. Hence, combined with a graphics processing unit acceleration algorithm, the DoFP polarization microscope is capable of real-time polarization imaging for potential quick clinical diagnoses of both standard and frozen slices of human carcinoma tissues.

  7. Astronomical Observing Conditions at Xinglong Observatory from 2007 to 2014

    Science.gov (United States)

    Zhang, Ji-Cheng; Ge, Liang; Lu, Xiao-Meng; Cao, Zi-Huang; Chen, Xu; Mao, Yong-Na; Jiang, Xiao-Jun

    2015-12-01

    Xinglong Observatory of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC), is one of the major optical observatories in China, which hosts nine optical telescopes including the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the 2.16 m reflector. Scientific research from these telescopes is focused on stars, galaxies, and exoplanets using multicolor photometry and spectroscopic observations. Therefore, it is important to provide the observing conditions of the site, in detail, to the astronomers for an efficient use of these facilities. In this article, we present the characterization of observing conditions at Xinglong Observatory based on the monitoring of meteorology, seeing and sky brightness during the period from 2007 to 2014. Meteorological data were collected from a commercial Automatic Weather Station (AWS), calibrated by China Meteorological Administration. Mean and median wind speed are almost constant during the period analyzed and ranged from 1.0 to 3.5 m s-1. However, high wind speed (>=15 m s-1) interrupts observations, mainly, during the winter and spring. Statistical analysis of air temperature showed the temperature difference between daytime and nighttime, which can be solved by opening the ventilation device and the slit of the dome at least 1 hr before observations. Analysis resulted in average percentage of photometric nights and spectroscopic nights are 32% and 63% per year, respectively. The distribution of photometric nights and spectroscopic nights has a significant seasonal tendency, worse in summer due to clouds, dust, and high humidity. Seeing measurements were obtained using the Differential Image Motion Monitor (DIMM). Mean and median values of seeing over 1 year are around 1.9'' and 1.7'', respectively. Eighty percent of nights with seeing values are below 2.6'', whereas the distribution peaks around 1.8''. The measurements of sky brightness are acquired from the Sky Quality Meter (SQM

  8. Public Perception of Astronomers: Revered, Reviled and Ridiculed

    OpenAIRE

    West, Michael J.

    2009-01-01

    Society's view of astronomers has changed over time and from culture to culture. This review discusses some of the many ways that astronomers have been perceived by their societies and suggests ways that astronomers can influence public perception of ourselves and our profession in the future.

  9. Revista Mexicana de Astronomía y Astrofísica, a real option for astronomical publication

    Science.gov (United States)

    Torres-Peimbert, S.; Allen, C.

    2011-10-01

    We present statistical data about the Revista Mexicana de Astronomía y Astrofísica. We consider that this journal is well positioned in the international astronomical literature. Similarly we present information about the Serie de Conferencias, which also has a wide level of acceptance by the astronomical community.

  10. Identifying seasonal stars in Kaurna astronomical traditions

    Science.gov (United States)

    Hamacher, Duane W.

    2015-03-01

    Early ethnographers and missionaries recorded Aboriginal languages and oral traditions across Australia. Their general lack of astronomical training resulted in misidentifications, transcription errors and omissions in these records. In western Victoria and southeast South Australia many astronomical traditions were recorded but, cur- iously, some of the brightest stars in the sky were omitted. Scholars claimed these stars did not feature in Aboriginal traditions. This continues to be repeated in the literature, but current research shows that these stars may in fact feature in Aboriginal traditions and could be seasonal calendar markers. This paper uses established techniques to identify seasonal stars in the traditions of the Kaurna Aboriginal people of the Adelaide Plains, South Australia.

  11. Statistical methods for astronomical data analysis

    CERN Document Server

    Chattopadhyay, Asis Kumar

    2014-01-01

    This book introduces “Astrostatistics” as a subject in its own right with rewarding examples, including work by the authors with galaxy and Gamma Ray Burst data to engage the reader. This includes a comprehensive blending of Astrophysics and Statistics. The first chapter’s coverage of preliminary concepts and terminologies for astronomical phenomenon will appeal to both Statistics and Astrophysics readers as helpful context. Statistics concepts covered in the book provide a methodological framework. A unique feature is the inclusion of different possible sources of astronomical data, as well as software packages for converting the raw data into appropriate forms for data analysis. Readers can then use the appropriate statistical packages for their particular data analysis needs. The ideas of statistical inference discussed in the book help readers determine how to apply statistical tests. The authors cover different applications of statistical techniques already developed or specifically introduced for ...

  12. International Astronomical Union Sympoisum No.50

    CERN Document Server

    Westerlund, B

    1973-01-01

    Dr J. Landi Dessy, Director of the Astronomical Observatory, Cordoba, Argentina, invited the International Astronomical Union to hold a Symposium in Cordoba in connection with the celebration of the Centennial of the Cordoba Observatory; the date of foundation is October 24, 1871. He proposed that the Symposium should deal with Spectral Classification and Multicolour Photometry as seven years had elapsed since the Symposium No. 24 in Saltsj6baden, and much development had occurred in the field. The invitation and the proposal were accepted by the IAU, and the Symposium was held in Villa Carlos Paz, near Cordoba, between October 18 and October 24, 1971. It was attended by about 50 scientists representing Argentina, Canada, Chile, Den­ mark, France, Germany, Italy, Mexico, Sweden, Switzerland, U.K., U.S.A., Vatican City State and Venezuela. The Symposium was divided into four sessions: 1. Classification of slit spectra, 2. Classification of objective-prism spectra, 3. Photometric classification, 4. Catalogues ...

  13. Carriers of the astronomical 2175 ? extinction feature

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, J; Dai, Z; Ernie, R; Browning, N; Graham, G; Weber, P; Smith, J; Hutcheon, I; Ishii, H; Bajt, S; Floss, C; Stadermann, F

    2004-07-20

    The 2175 {angstrom} extinction feature is by far the strongest spectral signature of interstellar dust observed by astronomers. Forty years after its discovery the origin of the feature and the nature of the carrier remain controversial. The feature is enigmatic because although its central wavelength is almost invariant its bandwidth varies strongly from one sightline to another, suggesting multiple carriers or a single carrier with variable properties. Using a monochromated transmission electron microscope and valence electron energy-loss spectroscopy we have detected a 5.7 eV (2175 {angstrom}) feature in submicrometer-sized interstellar grains within interplanetary dust particles (IDPs) collected in the stratosphere. The carriers are organic carbon and amorphous silicates that are abundant and closely associated with one another both in IDPs and in the interstellar medium. Multiple carriers rather than a single carrier may explain the invariant central wavelength and variable bandwidth of the astronomical 2175 {angstrom} feature.

  14. Recruitment and Retention of LGBTIQ Astronomers

    Science.gov (United States)

    Dixon, William Van Dyke

    2012-01-01

    While lesbian, gay, bisexual, transgender, intersex, or questioning (LGBTIQ) astronomers face many of the same workplace challenges as women and racial/ethnic minorities, from implicit bias to overt discrimination, other challenges are unique to this group. An obvious example is the absence at many institutions of health insurance and other benefits for the same-sex domestic partners of their employees. More subtle is the psychological toll paid by LGBTIQ astronomers who remain "in the closet," self-censoring every statement about their personal lives. Paradoxically, the culture of the physical sciences, in which sexuality, gender identity, and gender expression are considered irrelevant, can discourage their discussion, further isolating LGBTIQ researchers. Addressing these challenges is not just a matter of fairness; it is an essential tool in the recruitment and retention of the brightest researchers and in assuring their productivity. We will discuss these issues and what individuals and departments can to make their institutions more welcoming to their LGBTIQ colleagues.

  15. Extracting Knowledge From Massive Astronomical Data Sets

    CERN Document Server

    Brescia, Massimo; Djorgovski, S G; Donalek, Ciro; Longo, Giuseppe; Paolillo, Maurizio

    2011-01-01

    The exponential growth of astronomical data collected by both ground based and space borne instruments has fostered the growth of Astroinformatics: a new discipline laying at the intersection between astronomy, applied computer science, and information and computation (ICT) technologies. At the very heart of Astroinformatics is a complex set of methodologies usually called Data Mining (DM) or Knowledge Discovery in Data Bases (KDD). In the astronomical domain, DM/KDD are still in a very early usage stage, even though new methods and tools are being continuously deployed in order to cope with the Massive Data Sets (MDS) that can only grow in the future. In this paper, we briefly outline some general problems encountered when applying DM/KDD methods to astrophysical problems, and describe the DAME (DAta Mining & Exploration) web application. While specifically tailored to work on MDS, DAME can be effectively applied also to smaller data sets. As an illustration, we describe two application of DAME to two di...

  16. Detecting Diffuse Sources in Astronomical Images

    CERN Document Server

    Butler-Yeoman, T; Hollitt, C P; Hogg, D W; Johnston-Hollitt, M

    2016-01-01

    We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended sources often have no bright points and are only detectable when viewed as a whole, so a more sophisticated approach is required. Our algorithm operates at all scales simultaneously by considering a tree of nested candidate bounding boxes, and inverts a hierarchical Bayesian generative model to obtain the probability of sources existing at given locations and sizes. This model naturally accommodates the detection of nested sources, and no prior knowledge of the distribution of a source, or even the background, is required. The algorithm scales nearly linear with the number of pixels making it feasible to run on large images, and requires minimal parameter tweaking to be effective. We demonstrate the algorithm on several types of astronomical and artificial images.

  17. Division B Commission 6: Astronomical Telegrams

    Science.gov (United States)

    Yamaoka, H.; Green, D. W. E.; Samus, N. N.; Aksnes, K.; Gilmore, A. C.; Nakano, S.; Sphar, T.; Tichá, J.; Williams, G. V.

    2016-04-01

    IAU Commission 6 ``Astronomical Telegrams'' had a single business meeting during Honolulu General Assembly of the IAU. It took place on Tuesday, 11 August 2015. The meeting was attended by Hitoshi Yamaoka (President), Daniel Green (Director of the Central Bureau for Astronomical Telegrams, CBAT, via Skype), Steven Chesley (JPL), Paul Chodas (JPL), Alan Gilmore (Canterbury University), Shinjiro Kouzuma (Chukyo University), Paolo Mazzali (Co-Chair of the Supernova Working Group), Elena Pian (Scuola Normale Superiore di Pisa), Marion Schmitz (chair IAU Working Group Designations + NED), David Tholen (University of Hawaii), Jana Ticha (Klet Observatory), Milos Tichy (Klet Observatory), Giovanni Valsecchi (INAF\\slash Italy), Gareth Williams (Minor Planet Center). Apologies: Nikolai Samus (General Catalogue of Variable Stars, GCVS).

  18. Compression of interferometric radio-astronomical data

    CERN Document Server

    Offringa, A R

    2016-01-01

    The volume of radio-astronomical data is a considerable burden in the processing and storing of radio observations with high time and frequency resolutions and large bandwidths. Lossy compression of interferometric radio-astronomical data is considered to reduce the volume of visibility data and to speed up processing. A new compression technique named "Dysco" is introduced that consists of two steps: a normalization step, in which grouped visibilities are normalized to have a similar distribution; and a quantization and encoding step, which rounds values to a given quantization scheme using a dithering scheme. Several non-linear quantization schemes are tested and combined with different methods for normalizing the data. Four data sets with observations from the LOFAR and MWA telescopes are processed with different processing strategies and different combinations of normalization and quantization. The effects of compression are measured in image plane. The noise added by the lossy compression technique acts ...

  19. Astronomía Mocoví

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    El presente trabajo, es una revisión crítica de la astronomía en la cultura Mocoví, aportando a lo realizado previamente por Lehmann Nistche (Lehmann Nistche, 1924 y 1927) el resultado de nuestro trabajo de campo. Un mayor conocimiento de las cosmovisiones de las etnias de esta área es fundamental para una mejor comprensión de la dispersión de las ideas cosmológicas entre los pueblos aborígenes americanos, dada la importancia del corredor chaqueño como conexión entre las altas culturas andinas, la mesopotamia y la región pampeana (Susnik, 1972). Para ello se realiza una comparación con otras cosmovisiones del área americana. Nuestro aporte se enmarca dentro de las actuales líneas de trabajo mundialmente en desarrollo en Astronomía en la Cultura.

  20. Training the Next Generation of Astronomers

    CERN Document Server

    Williams, Peter K G; Maness, Holly; Modjaz, Maryam; Shapiro, Kristen L; Silverman, Jeffrey M; Strubbe, Linda; Adams, Betsey; Alatalo, Katherine; Chiu, Kuenley; Claire, Mark; Cobb, Bethany; Cruz, Kelle; Desroches, Louis-Benoit; Enoch, Melissa; Hull, Chat; Jang-Condell, Hannah; Law, Casey; McConnell, Nicholas; Meijerink, Rowin; Offner, Stella; Parejko, John K; Pober, Jonathan; Pontoppidan, Klaus; Poznanski, Dovi; Seth, Anil; Stahler, Steven; Walkowicz, Lucianne; West, Andrew A; Wetzel, Andrew; Whysong, David

    2009-01-01

    While both society and astronomy have evolved greatly over the past fifty years, the academic institutions and incentives that shape our field have remained largely stagnant. As a result, the astronomical community is faced with several major challenges, including: (1) the training that we provide does not align with the skills that future astronomers will need, (2) the postdoctoral phase is becoming increasingly demanding and demoralizing, and (3) our jobs are increasingly unfriendly to families with children. Solving these problems will require conscious engineering of our profession. Fortunately, this Decadal Review offers the opportunity to revise outmoded practices to be more effective and equitable. The highest priority of the Subcommittee on the State of the Profession should be to recommend specific, funded activities that will ensure the field meets the challenges we describe.

  1. Renewal Strings for Cleaning Astronomical Databases

    CERN Document Server

    Storkey, Amos J; Williams, Christopher K I; Mann, Robert G

    2014-01-01

    Large astronomical databases obtained from sky surveys such as the SuperCOSMOS Sky Surveys (SSS) invariably suffer from a small number of spurious records coming from artefactual effects of the telescope, satellites and junk objects in orbit around earth and physical defects on the photographic plate or CCD. Though relatively small in number these spurious records present a significant problem in many situations where they can become a large proportion of the records potentially of interest to a given astronomer. In this paper we focus on the four most common causes of unwanted records in the SSS: satellite or aeroplane tracks, scratches fibres and other linear phenomena introduced to the plate, circular halos around bright stars due to internal reflections within the telescope and diffraction spikes near to bright stars. Accurate and robust techniques are needed for locating and flagging such spurious objects. We have developed renewal strings, a probabilistic technique combining the Hough transform, renewal...

  2. Local sparse representation for astronomical image denoising

    Institute of Scientific and Technical Information of China (English)

    杨阿锋; 鲁敏; 滕书华; 孙即祥

    2013-01-01

    Motivated by local coordinate coding(LCC) theory in nonlinear manifold learning, a new image representation model called local sparse representation(LSR) for astronomical image denoising was proposed. Borrowing ideas from surrogate function and applying the iterative shrinkage-thresholding algorithm(ISTA), an iterative shrinkage operator for LSR was derived. Meanwhile, a fast approximated LSR method by first performing a K-nearest-neighbor search and then solving a l1optimization problem was presented under the guarantee of denoising performance. In addition, the LSR model and adaptive dictionary learning were incorporated into a unified optimization framework, which explicitly established the inner connection of them. Such processing allows us to simultaneously update sparse coding vectors and the dictionary by alternating optimization method. The experimental results show that the proposed method is superior to the traditional denoising method and reaches state-of-the-art performance on astronomical image.

  3. Bad pixel modified interpolation for astronomical images

    CERN Document Server

    Popowicz, A; Filus, Z

    2013-01-01

    We present a new method of interpolation for the pixel brightness estimation in astronomical images. Our new method is simple and easily implementable. We show the comparison of this method with the widely used linear interpolation and other interpolation algorithms using one thousand astronomical images obtained from the Sloan Digital Sky Survey. The comparison shows that our method improves bad pixels brightness estimation with four times lower mean error than the presently most popular linear interpolation and has a better performance than any other examined method. The presented idea is flexible and can be also applied to presently used and future interpolation methods. The proposed method is especially useful for large sky surveys image reduction but can be also applied to single image correction.

  4. Astronomical Image Denoising Using Dictionary Learning

    CERN Document Server

    Beckouche, Simon; Fadili, Jalal

    2013-01-01

    Astronomical images suffer a constant presence of multiple defects that are consequences of the intrinsic properties of the acquisition equipments, and atmospheric conditions. One of the most frequent defects in astronomical imaging is the presence of additive noise which makes a denoising step mandatory before processing data. During the last decade, a particular modeling scheme, based on sparse representations, has drawn the attention of an ever growing community of researchers. Sparse representations offer a promising framework to many image and signal processing tasks, especially denoising and restoration applications. At first, the harmonics, wavelets, and similar bases and overcomplete representations have been considered as candidate domains to seek the sparsest representation. A new generation of algorithms, based on data-driven dictionaries, evolved rapidly and compete now with the off-the-shelf fixed dictionaries. While designing a dictionary beforehand leans on a guess of the most appropriate repre...

  5. Identifying seasonal stars in Kaurna astronomical traditions

    CERN Document Server

    Hamacher, Duane W

    2015-01-01

    Early ethnographers and missionaries recorded Aboriginal languages and oral traditions across Australia. Their general lack of astronomical training resulted in misidentifications, transcription errors, and omissions in these records. Additionally, many of these early records are fragmented. In western Victoria and southeast South Australia, many astronomical traditions were recorded, but curiously, some of the brightest stars in the sky were omitted. Scholars claimed these stars did not feature in Aboriginal traditions. This under-representation continues to be repeated in the literature, but current research shows that some of these stars may in fact feature in Aboriginal traditions and could be seasonal calendar markers. This paper uses established techniques in cultural astronomy to identify seasonal stars in the traditions of the Kaurna Aboriginal people of the Adelaide Plains, South Australia.

  6. The la Plata Astronomical Data Center

    Science.gov (United States)

    Marraco, H. G.

    1990-11-01

    RESUMEN. El Centro de Datos Astron6micos tiene su sede en la Facuitad de Ciencias Astron6micas y Geofisicas d la Universidad Nacional de La Plata y funciona por convenio entre esta facultad y el Centre des Stellaires de la Universite' Louis Pasteur en Estrasburgo (CDS), Francia. La finalidad de este centro es la de proveer a los astr6nomos del area con copias de los alrededor de 500 acumulados y/o preparados por el CDS a la vez que promover la producci6n y/o acumulaci6n de en el rea. Para la realizaci6n de esta tarea se cuenta con el apoyo del Centro Superior para el Procesamiento de la Informaci6n (CESPI) de la UNLP cuyos equipos se describen. Las tareas que se estan realizando incluyen la distribuci6n de SIMBAD a los astr6nomos argentinos y se efectuan ensayos de distribuci6n en linea de CD-ROM TEST DISK del Astronomical Data Center (ADC) de la NASA que contiene los 31 mas solicitados por los astr6nomos de todo el mundo. ABSTRACl The La Plata Astronomical Data Center operates by an agreement between the Facultad de Ciencias Astron6micas y Geofisicas at La Plata University and the Centre des Donnees Stellaires of Louis Pasteur University at Strasbourg (CDS), France. The purpose of the Center is to provide to the area astronomers with copies of the catalogs they need amongst those stored and/or prepared at CDS. At the same time the center will act of the astronomical data produced within its area. K words: DATA ANALYSIS

  7. Astronomy Legacy Project - Pisgah Astronomical Research Institute

    Science.gov (United States)

    Barker, Thurburn; Castelaz, Michael W.; Rottler, Lee; Cline, J. Donald

    2016-01-01

    Pisgah Astronomical Research Institute (PARI) is a not-for-profit public foundation in North Carolina dedicated to providing hands-on educational and research opportunities for a broad cross-section of users in science, technology, engineering and math (STEM) disciplines. In November 2007 a Workshop on a National Plan for Preserving Astronomical Photographic Data (2009ASPC,410,33O, Osborn, W. & Robbins, L) was held at PARI. The result was the establishment of the Astronomical Photographic Data Archive (APDA) at PARI. In late 2013 PARI began ALP (Astronomy Legacy Project). ALP's purpose is to digitize an extensive set of twentieth century photographic astronomical data housed in APDA. Because of the wide range of types of plates, plate dimensions and emulsions found among the 40+ collections, plate digitization will require a versatile set of scanners and digitizing instruments. Internet crowdfunding was used to assist in the purchase of additional digitization equipment that were described at AstroPlate2014 Plate Preservation Workshop (www.astroplate.cz) held in Prague, CZ, March, 2014. Equipment purchased included an Epson Expression 11000XL scanner and two Nikon D800E cameras. These digital instruments will compliment a STScI GAMMA scanner now located in APDA. GAMMA will be adapted to use an electroluminescence light source and a digital camera with a telecentric lens to achieve high-speed high-resolution scanning. The 1μm precision XY stage of GAMMA will allow very precise positioning of the plate stage. Multiple overlapping CCD images of small sections of each plate, tiles, will be combined using a photo-mosaic process similar to one used in Harvard's DASCH project. Implementation of a software pipeline for the creation of a SQL database containing plate images and metadata will be based upon APPLAUSE as described by Tuvikene at AstroPlate2014 (www.astroplate.cz/programs/).

  8. Astronomical orientations in sanctuaries of Daunia

    CERN Document Server

    Antonello, E; Sisto, A M Tunzi; LoZupone, M

    2013-01-01

    Prehistoric sanctuaries of Daunia date back several thousand years. During the Neolithic and Bronze Age the farmers in that region dug hypogea and holes whose characteristics suggest a ritual use. In the present note we summarize the results of the astronomical analysis of the orientation of the row holes in three different sites, and we point out the possible use of the setting of the stars of Centaurus. An interesting archaeological confirmation of an archaeoastronomical prediction is also reported.

  9. An Astronomer's View of Climate Change

    CERN Document Server

    Morton, Donald C

    2014-01-01

    This paper describes some of the astronomical effects that could be important for understanding the ice ages, historic climate changes and the recent temperature increase. These include changes in the sun's luminosity, periodic changes in the earth's orbital parameters, the sun's orbit around our galaxy, the variability of solar activity and the anticorrelation of cosmic ray flux with that activity. Finally recent trends in solar activity and global temperatures are compared with the predictions of climate models.

  10. A Polarimeter for GeV Linearly-polarized Photon Beams

    Science.gov (United States)

    Wood, M. H.; Tedeschi, D.; Wojtsekhowski, B.; Abbott, D.; Nelyubin, V.; Vlahovic, B.; Asai, J.; Feldman, G.; O'Rielly, G.; Khandaker, Mahbub; Hotta, T.; Kohri, H.; Matsumura, T.; Mibe, T.; Nakano, T.; Yorita, T.; Rudge, A.; Weilhammer, P.; Zegers, R.

    2003-04-01

    We have built a polarimeter for linearly-polarized photon beams in the few GeV photon-energy range. The technique is to detect an electron-positron pair produced from a photon incident on a thin converter. The orientation and the distance separating the e^+ and e^- are measured accurately with silicon-microstrip detectors. The polarimeter was calibrated at the SPring-8 facility using a compton-backscattered photon beam in the energy range of 1.5 GeV ≤ E_γ ≤ 2.4 GeV. This measurement was the first made for the process at these energies. Results will be presented of the measured asymmetry between horizontally and vertically polarized beams.

  11. Measurements of the Polarization Properties of Foam Materials Useful for mm-wave Polarimeters Windows

    Science.gov (United States)

    Coppi, G.; Marchetti, T.; de Bernardis, P.; Masi, S.

    2016-08-01

    We have measured in the W-band, using a custom setup, the absorption and polarization properties in transmission of foam materials (elyfoamⓇ, styrodurⓇ, plastazoteⓇ, and propozoteⓇ) useful for windows of mm-wave photometers and polarimeters. The levels of the induced polarization degree and of the absorption are very small, and difficult to measure accurately. We find induced polarization degrees lower than 0.6 %, and transmissions higher than 97 % for few centimeter thicknesses of our samples. We describe the instrumental setup, the measurements, and the impact of our findings in the design of precision polarimeters for Cosmic Microwave Background measurements. All these materials, with the exception of black plastazoteⓇ, feature transmissions higher than 99 %, and induced polarizations lower than ˜1 % for sample thicknesses around 2-3 cm.

  12. A novel comparison of M{\\o}ller and Compton electron-beam polarimeters

    CERN Document Server

    Magee, J A; Jones, D; Beminiwattha, R; Cornejo, J C; Dalton, M M; Deconinck, W; Dutta, D; Gaskell, D; Martin, J W; Paschke, K D; Tvaskis, V; Asaturyan, A; Benesch, J; Cates, G; Cavness, B S; Dillon-Townes, L A; Hays, G; Hoskins, J; Ihloff, E; Jones, R; King, P M; Kowalski, S; Kurchaninov, L; Lee, L; McCreary, A; McDonald, M; Micherdzinska, A; Mkrtchyan, A; Mkrtchyan, H; Nelyubin, V; Page, S; Ramsay, W D; Solvignon, P; Storey, D; Tobias, W A; Urban, E; Vidal, C; Waidyawansa, B; Wang, P; Zhamkotchyan, S

    2016-01-01

    We have performed a novel comparison between electron-beam polarimeters based on M{\\o}ller and Compton scattering. A sequence of electron-beam polarization measurements were performed at low beam currents ($<$ 5 $\\mu$A) during the $Q_{\\rm weak}$ experiment in Hall C at Jefferson Lab. These low current measurements were bracketed by the regular high current (180 $\\mu$A) operation of the Compton polarimeter. All measurements were found to be consistent within experimental uncertainties of 1% or less, demonstrating that electron polarization does not depend significantly on the beam current. This result lends confidence to the common practice of applying M{\\o}ller measurements made at low beam currents to physics experiments performed at higher beam currents. The agreement between two polarimetry techniques based on independent physical processes sets an important benchmark for future precision asymmetry measurements that require sub-1% precision in polarimetry.

  13. An imaging spectro-polarimeter for measuring hemispherical spectrally resolved down-welling sky polarization

    Science.gov (United States)

    Chenault, David B.; Pezzaniti, J. L.; Roche, Michael; Hyatt, Brian

    2016-05-01

    A full sky imaging spectro-polarimeter has been developed that measures spectrally resolved (~2.5 nm resolution) radiance and polarization (𝑠0, 𝑠1, 𝑠2 Stokes Elements) of natural sky down-welling over approximately 2π sr between 400nm and 1000nm. The sensor is based on a scanning push broom hyperspectral imager configured with a continuously rotating polarizer (sequential measurement in time polarimeter). Sensor control and processing software (based on Polaris Sensor Technologies Grave' camera control software) has a straight-forward and intuitive user interface that provides real-time updated sky down-welling spectral radiance/polarization maps and statistical analysis tools.

  14. A correlation polarimeter for noise-like signals. [optimum estimation of linearly polarized electromagnetic wave

    Science.gov (United States)

    Ohlson, J. E.

    1976-01-01

    Optimum estimation (tracking) of the polarization plane of a linearly polarized electromagnetic wave is determined when the signal is a narrow-band Gaussian random process with a polarization plane angle which is also a Gaussian random process. This model is compared to previous work and is applicable to space communication. The estimator performs a correlation operation similar to an amplitude-comparison monopulse angle tracker, giving the name correlation polarimeter. Under large signal-to-noise ratio (SNR), the estimator is causal. Performance of the causal correlation polarimeter is evaluated for arbitrary SNR. Optimum precorrelation filtering is determined. With low SNR, the performance of this system is far better than that of previously developed systems. Practical implementation is discussed. A scheme is given to reduce the effect of linearly polarized noise.

  15. Analysis of Data from the Balloon Borne Gamma RAy Polarimeter Experiment (GRAPE)

    Science.gov (United States)

    Wasti, Sambid K.; Bloser, Peter F.; Legere, Jason S.; McConnell, Mark L.; Ryan, James M.

    2016-04-01

    The Gamma Ray Polarimeter Experiment (GRAPE), a balloon borne polarimeter for 50~300 keV gamma rays, successfully flew in 2011 and 2014. The main goal of these balloon flights was to measure the gamma ray polarization of the Crab Nebula. Analysis of data from the first two balloon flights of GRAPE has been challenging due to significant changes in the background level during each flight. We have developed a technique based on the Principle Component Analysis (PCA) to estimate the background for the Crab observation. We found that the background depended mostly on the atmospheric depth, pointing zenith angle and instrument temperatures. Incorporating Anti-coincidence shield data (which served as a surrogate for the background) was also found to improve the analysis. Here, we present the calibration data and describe the analysis done on the GRAPE 2014 flight data.

  16. A high-sensitivity polarimeter using a ferro-electric liquid crystal modulator

    CERN Document Server

    Bailey, Jeremy; Cotton, Daniel; Bott, Kimberly; Hough, J H; Lucas, P W

    2015-01-01

    We describe the HIgh Precision Polarimetric Instrument (HIPPI), a polarimeter built at UNSW Australia and used on the Anglo-Australian Telescope (AAT). HIPPI is an aperture polarimeter using a ferro-electric liquid crystal modulator. HIPPI measures the linear polarization of starlight with a sensitivity in fractional polarization of ~4 x 10$^{-6}$ on low polarization objects and a precision of better than 0.01% on highly polarized stars. The detectors have a high dynamic range allowing observations of the brightest stars in the sky as well as much fainter objects. The telescope polarization of the AAT is found to be 48 $\\pm$ 5 x 10$^{-6}$ in the g' band.

  17. The White Mountain Polarimeter Telescope and an Upper Limit on CMB Polarization

    CERN Document Server

    Levy, Alan R; Ansmann, Markus; Bersanelli, Marco; Childers, Jeffery; Cole, Terrence D; D'Arcangelo, Ocleto; Davis, G Vietor; Lubin, Philip M; Marvil, Joshua; Meinhold, Peter R; Miller, Gerald; O`Neill, Hugh; Stavola, Fabrizio; Stebor, Nathan C; Timbie, Peter T; van der Heide, Maarten; Villa, Fabrizio; Villela, Thyrso; Williams, Brian D; Wuensche, Carlos A

    2008-01-01

    The White Mountain Polarimeter (WMPol) is a dedicated ground-based microwave telescope and receiver system for observing polarization of the Cosmic Microwave Background. WMPol is located at an altitude of 3880 meters on a plateau in the White Mountains of Eastern California, USA, at the Barcroft Facility of the University of California White Mountain Research Station. Presented here is a description of the instrument and the data collected during April through October 2004. We set an upper limit on $E$-mode polarization of 14 $\\mu\\mathrm{K}$ (95% confidence limit) in the multipole range $170<\\ell<240$. This result was obtained with 422 hours of observations of a 3 $\\mathrm{deg}^2$ sky area about the North Celestial Pole, using a 42 GHz polarimeter. This upper limit is consistent with $EE$ polarization predicted from a standard $\\Lambda$-CDM concordance model.

  18. AWOB: A Collaborative Workbench for Astronomers

    Science.gov (United States)

    Kim, J. W.; Lemson, G.; Bulatovic, N.; Makarenko, V.; Vogler, A.; Voges, W.; Yao, Y.; Kiefl, R.; Koychev, S.

    2015-09-01

    We present the Astronomers Workbench (AWOB1), a web-based collaboration and publication platform for a scientific project of any size, developed in collaboration between the Max-Planck institutes of Astrophysics (MPA) and Extra-terrestrial Physics (MPE) and the Max-Planck Digital Library (MPDL). AWOB facilitates the collaboration between geographically distributed astronomers working on a common project throughout its whole scientific life cycle. AWOB does so by making it very easy for scientists to set up and manage a collaborative workspace for individual projects, where data can be uploaded and shared. It supports inviting project collaborators, provides wikis, automated mailing lists, calendars and event notification and has a built in chat facility. It allows the definition and tracking of tasks within projects and supports easy creation of e-publications for the dissemination of data and images and other resources that cannot be added to submitted papers. AWOB extends the project concept to larger scale consortia, within which it is possible to manage working groups and sub-projects. The existing AWOB instance has so far been limited to Max-Planck members and their collaborators, but will be opened to the whole astronomical community. AWOB is an open-source project and its source code is available upon request. We intend to extend AWOB's functionality also to other disciplines, and would greatly appreciate contributions from the community.

  19. GalileoMobile: Astronomical activities in schools

    Science.gov (United States)

    Dasi Espuig, Maria; Vasquez, Mayte; Kobel, Philippe

    GalileoMobile is an itinerant science education initiative run on a voluntary basis by an international team of astronomers, educators, and science communicators. Our team's main goal is to make astronomy accessible to schools and communities around the globe that have little or no access to outreach actions. We do this by performing teacher workshops, activities with students, and donating educational material. Since the creation of GalileoMobile in 2008, we have travelled to Chile, Bolivia, Peru, India, and Uganda, and worked with 56 schools in total. Our activities are centred on the GalileoMobile Handbook of Activities that comprises around 20 astronomical activities which we adapted from many different sources, and translated into 4 languages. The experience we gained in Chile, Bolivia, Peru, India, and Uganda taught us that (1) bringing experts from other countries was very stimulating for children as they are naturally curious about other cultures and encourages a collaboration beyond borders; (2) high-school students who were already interested in science were always very eager to interact with real astronomers doing research to ask for career advice; (3) inquiry-based methods are important to make the learning process more effective and we have therefore, re-adapted the activities in our Handbook according to these; (4) local teachers and university students involved in our activities have the potential to carry out follow-up activities, and examples are those from Uganda and India.

  20. AAS Publishing News: Astronomical Software Citation Workshop

    Science.gov (United States)

    Kohler, Susanna

    2015-07-01

    Do you write code for your research? Use astronomical software? Do you wish there were a better way of citing, sharing, archiving, or discovering software for astronomy research? You're not alone! In April 2015, AAS's publishing team joined other leaders in the astronomical software community in a meeting funded by the Sloan Foundation, with the purpose of discussing these issues and potential solutions. In attendance were representatives from academic astronomy, publishing, libraries, for-profit software sharing platforms, telescope facilities, and grantmaking institutions. The goal of the group was to establish “protocols, policies, and platforms for astronomical software citation, sharing, and archiving,” in the hopes of encouraging a set of normalized standards across the field. The AAS is now collaborating with leaders at GitHub to write grant proposals for a project to develop strategies for software discoverability and citation, in astronomy and beyond. If this topic interests you, you can find more details in this document released by the group after the meeting: http://astronomy-software-index.github.io/2015-workshop/ The group hopes to move this project forward with input and support from the broader community. Please share the above document, discuss it on social media using the hashtag #astroware (so that your conversations can be found!), or send private comments to julie.steffen@aas.org.

  1. David Gill - Magnificent and Desirable Astronomer

    CERN Document Server

    Reid, John S

    2016-01-01

    This paper was given to mark the centenary of the death of David Gill, the foremost British astronomer in the last quarter of the 19th century and into the 20th century. Gill abandoned a successful career as a clock and watchmaker. His speciality was in astrometry, an area of astronomy of both practical and scientific importance that tended to be eclipsed in the 20th century by the rise of astrophysics. As Her Majesty's Astronomer at the Cape of Good Hope for 27 years, David Gill was admired for his prolific contribution to highly accurate and trustworthy results. David Gill's collaboration was desired by leading astronomers of the day and he was the only southern hemisphere representative on the hugely important Conference Internationale des Etoiles Fondamentales of 1896. He created with Jacobus Kapetyn the first extensive star catalogue derived from photographic plates (the CPD), including over 450,000 stars. He was an initiator of the biggest multi-national and multi-observatory project of the century, tak...

  2. Astrobiology: An astronomer's perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bergin, Edwin A. [University of Michigan, Department of Astronomy, 500 Church Street, Ann Arbor, MI 48109 (United States)

    2014-12-08

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track the gaseous and solid molecular carriers of these volatiles throughout the process of star and planet formation. It is now clear that the early stages of star formation fosters the creation of water and simple organic molecules with enrichments of heavy isotopes. These molecules are found as ice coatings on the solid materials that represent microscopic beginnings of terrestrial worlds. Based on the meteoritic and cometary record, the process of planet formation, and the local environment, lead to additional increases in organic complexity. The astronomical connections towards this stage are only now being directly made. Although the exact details are uncertain, it is likely that the birth process of star and planets likely leads to terrestrial worlds being born with abundant water and organics on the surface.

  3. Astrobiology: An astronomer's perspective

    International Nuclear Information System (INIS)

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track the gaseous and solid molecular carriers of these volatiles throughout the process of star and planet formation. It is now clear that the early stages of star formation fosters the creation of water and simple organic molecules with enrichments of heavy isotopes. These molecules are found as ice coatings on the solid materials that represent microscopic beginnings of terrestrial worlds. Based on the meteoritic and cometary record, the process of planet formation, and the local environment, lead to additional increases in organic complexity. The astronomical connections towards this stage are only now being directly made. Although the exact details are uncertain, it is likely that the birth process of star and planets likely leads to terrestrial worlds being born with abundant water and organics on the surface

  4. On the Astronomical Records and Babylonian Chronology

    CERN Document Server

    Gurzadyan, V G

    2000-01-01

    We outline the priority of high quality data of astronomical content as our strategy for the analysis of the ancient astronomical records in the search of the absolute chronology of the Near East in II millennium BC. The correspondingly defined set of data for two lunar eclipses of EAE 20 and 21 tablets linked to Ur III period enables us the choice of eclipses of 27 June 1954 BC and 17 March 1912 BC; here the information on the exit position of the darkening of the lunar disk acts as a crucial informator survived in the records. We then discuss why the 56/64 year Venus cycle cannot be traced in the Venus Tablet and therefore cannot serve as an anchor for the search of chronologies. The month length method is discussed as well. In sum the available data support the Ultra-Low Chronology proposed in the book by H.Gasche, J.A.Armstrong, S.W.Cole and V.G.Gurzadyan, "Dating the Fall of Babylon" (1998) and, particularly, leave no astronomical background for the High Chronology. Ultra-Low Chronology is supported also...

  5. Waveform dependence on signal amplitude in the RHIC H-Jet polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Poblaguev, A. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-02-25

    A simulation of the signal waveform in the H-Jet polarimeter is discussed. The simulation includes a model of charge collection in the silicon detector and a response functions of the H-Jet front end electronics. Results of the simulation are compared with experimental data. It is shown that an analysis of the signal shape may help to suppress background in the H-Jet polarization measurements.

  6. Compton polarimeter for 10–30 keV x rays

    Energy Technology Data Exchange (ETDEWEB)

    Weber, S.; Beilmann, C.; Shah, C.; Tashenov, S. [Physics Institute, Heidelberg University, 69120 Heidelberg (Germany)

    2015-09-15

    We present a simple and versatile polarimeter for x rays in the energy range of 10–30 keV. It uses Compton scattering in low-Z materials such as beryllium or boron carbide. The azimuthal distribution of the scattered x rays is sampled by an array of 12 silicon PIN diodes operated at room temperature. We evaluated the polarimetry performance using Monte-Carlo simulations and show experimental results.

  7. Compton polarimeter for 10-30 keV x rays

    Science.gov (United States)

    Weber, S.; Beilmann, C.; Shah, C.; Tashenov, S.

    2015-09-01

    We present a simple and versatile polarimeter for x rays in the energy range of 10-30 keV. It uses Compton scattering in low-Z materials such as beryllium or boron carbide. The azimuthal distribution of the scattered x rays is sampled by an array of 12 silicon PIN diodes operated at room temperature. We evaluated the polarimetry performance using Monte-Carlo simulations and show experimental results.

  8. POMME-HYPOM: a vector and tensor deuteron polarimeter up to 2 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Tomasi-Gustafsson, E.; Ball, J.; Boivin, M.; Kunne, R.; Ladygin, V.P.; Yonnet, J. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Bimbot, L.; Bisson, Y.; Boyard, J.L.; Courtat, PH.; Gacougnolle, R.; Slowron, R.; Hennino, T.; Morlet, M. [Centre National de la Recherche Scientifique (CNRS), 91 - Orsay (France). Lab. de l`Horloge Atomique; Cheung, N.E.; Jones, M.K.; Perdrisat, C.F. [College of William and Mary, Williamsburg, VA (United States); Punjabi, V. [Norfolk State Univ., VA (United States); Borzunov, Y.; Golovanov, L.; Ladygin, V.P.; Piskunov, N.M.; Sitnik, I.M.; Strokovsky, E.A.; Tsvinev, A.P.

    1996-12-31

    We present the last results obtained at Saturne on the measurement of vector and tensor analyzing powers of deuterons at high energy. The calibration of the effective analyzing powers of POMME has been completed up to 1.8 GeV. Moreover a tensor deuteron polarimeter HYPOM based on d,p elastic scattering, has been tested under beam at 1.6 GeV. (authors). 7 refs.

  9. Calibration of the polarimeter POMME with polarized deuterons at 1.8 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Tomasi-Gustafsson, E. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Ladygin, V.P. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Boivin, M. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Boyard, J.L. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 -Gif-sur-Yvette (France); Jaeckle, V. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Morsch, P. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Kunne, R. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Plouin, F. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Wurzinger, R. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Bimbot, L. [CNRS/IN2P3 IPN, 91400 Orsay (France); Djalali, C. [CNRS/IN2P3 IPN, 91400 Orsay (France); Farhi, L. [CNRS/IN2P3 IPN, 91400 Orsay (France); Hennino, T. [CNRS/IN2P3 IPN, 91400 Orsay (France); Jourdain, J.C. [CNRS/IN2P3 IPN, 91400 Orsay (France); Morlet, M. [CNRS/IN2P3 IPN, 91400 Orsay (France); Ramstein, B. [CNRS/IN2P3 IPN, 91400 Orsay (France); Rosier, L.H. [CNRS/IN2P3 IPN, 91400 Orsay (France); Roy-Stephan, M. [CNRS/IN2P3 IPN, 91400 Orsay (France); Wiele, J. van de [CNRS/IN2P3 IPN, 91400 Orsay (France); Jones, M.K. [College of William and Mary, Williamsburg, VA (United States); Perdrisat, C.F. [College of William and Mary, Williamsburg, VA (United States); Punjabi, V. [Norfolk State Univ., VA (United States); Glashausser, C. [Rutgers - the State Univ., New Brunswick, NJ (United States); Piskunov, N.M. [Joint Inst. for Nuclear Research, Dubna (Russian Federation); Sitnik, I.M. [Joint Inst. for Nuclear Research, Dubna (Russian Federation); Strokovsky, E.A. [Joint Inst. for Nuclear Research, Dubna (Russian Federation)

    1995-11-21

    We report here the results of the calibration of the polarimeter POMME for vector polarized deuterons at an energy of 1.8 GeV. The results show that inclusive deuteron-carbon scattering has substantial vector analyzing power even at this high energy. The results obtained on two analyzers, carbon, which is generally used and a lighter material, paraffin, are found to be similar. (orig.).

  10. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz Detector Array of Bolometric Polarimeters

    Science.gov (United States)

    Appel, John W.; Ali, Aamir; Amiri, Mandana; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Kogut, Alan J..; Miller, Nathan; Moseley, Samuel H.; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  11. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz detector array of bolometric polarimeters

    CERN Document Server

    Appel, John W; Amiri, Mandana; Araujo, Derek; Bennett, Charles L; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Hilton, Gene; Hinshaw, Gary F; Huang, Caroline; Irwin, Kent; Jones, Glenn; Karakla, John; Kogut, Alan J; Larson, David; Limon, Michele; Lowry, Lindsay; Marriage, Tobias; Mehrle, Nicholas; Miller, Amber D; Miller, Nathan; Moseleyb, Samuel H; Novakh, Giles; Reintsemad, Carl; Rostemab, Karwan; Stevensonb, Thomas; Towner, Deborah; U-Yen, Kongpop; Wagner, Emily; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  12. The low Q$^2$ chicane and Compton polarimeter at the JLab EIC

    Energy Technology Data Exchange (ETDEWEB)

    Camsonne, Alexandre [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-03-01

    The JLAB EIC (JLEIC) design includes a chicane after the interaction point to detect electron associated with production of quasi-real photon at the interaction. This chicane layout can also be used for Compton polarimetry to measure the electron beam polarization. This proceeding will present the layout of the low Q^2 chicane and the implementation and current R&D; of a Compton polarimeter which would be located in the middle of this chicane.

  13. Polarized H- Jet Polarimeter For Absolute Proton Polarization Measurements in RHIC

    International Nuclear Information System (INIS)

    Status of the H-jet polarimeter development is reviewed. A number of design issues are discussed including vacuum system, integration into the RHIC storage ring, scattering chamber, and uniform vertical holding field magnet design. The absolute proton polarization of the atomic hydrogen-jet target will be measured to 3% accuracy by a Breit- systematic error contribution to the jet-target polarization measurements is also discussed

  14. A three-cell liquid hydrogen target for an extended focal plane polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Golovanov, L.B.; Borzounov, Yu.T.; Piskunov, N.M.; Tsvinev, A.P. [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of High Energy; Ball, J.; Chesny, Ph.; Gheller, J.M.; Guillier, G.; Ladygin, V.P.; Theure, Ph.; Tomasi-Gustafsson, E. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1996-12-31

    This article describes the design and working principle of a 3-cell liquid hydrogen target produced for the high-energy deuteron polarimeter HYPOM. This target uses liquid Helium as a cooling agent. After a general description of the apparatus, tests and operating modes are thoroughly explained. In particular the air controlled self regulation of Helium flow in the cryostat to stabilize the liquid hydrogen level is presented. (author). 12 refs.; Submitted to Nuclear Instruments and Methods, A (NL).

  15. Polarization Aberrations in Astronomical Telescopes: The Point Spread Function

    Science.gov (United States)

    Breckinridge, James B.; Lam, Wai Sze T.; Chipman, Russell A.

    2015-05-01

    Detailed knowledge of the image of the point spread function (PSF) is necessary to optimize astronomical coronagraph masks and to understand potential sources of errors in astrometric measurements. The PSF for astronomical telescopes and instruments depends not only on geometric aberrations and scalar wave diffraction but also on those wavefront errors introduced by the physical optics and the polarization properties of reflecting and transmitting surfaces within the optical system. These vector wave aberrations, called polarization aberrations, result from two sources: (1) the mirror coatings necessary to make the highly reflecting mirror surfaces, and (2) the optical prescription with its inevitable non-normal incidence of rays on reflecting surfaces. The purpose of this article is to characterize the importance of polarization aberrations, to describe the analytical tools to calculate the PSF image, and to provide the background to understand how astronomical image data may be affected. To show the order of magnitude of the effects of polarization aberrations on astronomical images, a generic astronomical telescope configuration is analyzed here by modeling a fast Cassegrain telescope followed by a single 90° deviation fold mirror. All mirrors in this example use bare aluminum reflective coatings and the illumination wavelength is 800 nm. Our findings for this example telescope are: (1) The image plane irradiance distribution is the linear superposition of four PSF images: one for each of the two orthogonal polarizations and one for each of two cross-coupled polarization terms. (2) The PSF image is brighter by 9% for one polarization component compared to its orthogonal state. (3) The PSF images for two orthogonal linearly polarization components are shifted with respect to each other, causing the PSF image for unpolarized point sources to become slightly elongated (elliptical) with a centroid separation of about 0.6 mas. This is important for both astrometry

  16. Enhanced Management of Personal Astronomical Data with FITSManager

    CERN Document Server

    Cui, Chenzhou; Zhao, Yongheng; Kembhavi, Ajit; He, Boliang; Cao, Zihuang; Li, Jian; Nandrekar, Deoyani

    2011-01-01

    Although the roles of data centers and computing centers are becoming more and more important, and on-line research is becoming the mainstream for astronomy, individual research based on locally hosted data is still very common. With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer's personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their ...

  17. Development of a Hydrogen Møller Polarimeter for Precision Parity-Violating Electron Scattering

    Science.gov (United States)

    Gray, Valerie M.

    2013-10-01

    Parity-violating electron scattering experiments allow for testing the Standard Model at low energy accelerators. Future parity-violating electron scattering experiments, like the P2 experiment at the Johannes Gutenberg University, Mainz, Germany, and the MOLLER and SoLID experiments at Jefferson Lab will measure observables predicted by the Standard Model to high precision. In order to make these measurements, we will need to determine the polarization of the electron beam to sub-percent precision. The present way of measuring the polarization, with Møller scattering in iron foils or using Compton laser backscattering, will not easily be able to reach this precision. The novel Hydrogen Møller Polarimeter presents a non-invasive way to measure the electron polarization by scattering the electron beam off of atomic hydrogen gas polarized in a 7 Tesla solenoidal magnetic trap. This apparatus is expected to be operational by 2016 in Mainz. Currently, simulations of the polarimeter are used to develop the detection system at College of William & Mary, while the hydrogen trap and superconducting solenoid magnet are being developed at the Johannes Gutenberg University, Mainz. I will discuss the progress of the design and development of this novel polarimeter system. This material is based upon work supported by the National Science Foundation under Grant No. PHY-1206053.

  18. Studies and proposed changes to the RHIC p-Carbon polarimeters for the upcoming RUN-11

    Energy Technology Data Exchange (ETDEWEB)

    Makdisi, Y.; Alekseev, I.; Aschenauer, E.; Atoian, G.; Bazilevsky, A.; Gill, R.; Huang, H.; Morozov, B.; Svirida, D.; Yip, K.; Zelenski, A.

    2010-09-27

    The RHIC polarized proton complex utilizes polarimeters in each of the Blue and Yellow beams that measure the beam polarization through the p-Carbon elastic scattering process in the Coulomb Nuclear Interference kinematic region. This along with a Polarized Hydrogen Jet Target that utilizes the proton-proton elastic scattering process to first measure the analyzing power of the reaction and using the reverse process to measure the beam polarization. The latter is used to calibrate the p-Carbon polarimeters at the desired beam energy. In Run 9 RHIC ran with beams at center-of-mass energies of 200 and 500 GeV respectively. The higher beam intensities as well as the fact that the 250 GeV beam size is much smaller than that at 100 GeV resulted in significantly higher rates seen by the polarimeters and led to observed instability. In this paper, we will discuss the problems encountered and the tests that were carried out using the AGS as a proxy in an attempt to solve the problems and the path forward we took towards the upcoming polarized proton Run11.

  19. Studies and proposed changes to the RHIC p-Carbon polarimeters for the upcoming RUN-11

    International Nuclear Information System (INIS)

    The RHIC polarized proton complex utilizes polarimeters in each of the Blue and Yellow beams that measure the beam polarization through the p-Carbon elastic scattering process in the Coulomb Nuclear Interference kinematic region. This along with a Polarized Hydrogen Jet Target that utilizes the proton-proton elastic scattering process to first measure the analyzing power of the reaction and using the reverse process to measure the beam polarization. The latter is used to calibrate the p-Carbon polarimeters at the desired beam energy. In Run 9 RHIC ran with beams at center-of-mass energies of 200 and 500 GeV respectively. The higher beam intensities as well as the fact that the 250 GeV beam size is much smaller than that at 100 GeV resulted in significantly higher rates seen by the polarimeters and led to observed instability. In this paper, we will discuss the problems encountered and the tests that were carried out using the AGS as a proxy in an attempt to solve the problems and the path forward we took towards the upcoming polarized proton Run11.

  20. RHIC pC CNI Polarimeter: Experimental Setup and Physics Results

    International Nuclear Information System (INIS)

    Acceleration of polarized proton beams and experiments with them at RHIC require fast and reliable measurements of the polarization. The polarimeter presented here uses very high figure of merit of the elastic pC scattering at very low momenta transfer since the cross section is large. Small (a few percent) analysing power of the reaction makes it necessary to collect about 107 events per measurement. A deadtimeless DAQ system for the polarimeter is discussed in this paper. It is based on the waveform digitizer modules with 'on-board' event analysis, resulting in typical polarization measurement times of several tens of seconds. During winter 2001/2002 RHIC polarized run several dedicated data runs were taken by the polarimeter to extract the form of the analyzing power dependence as a function of the momentum transferred at beam energies 24 and 100 GeV. This dependence is extremely important for the theoretical understanding of the CNI process including the contribution of the spin-flip hadronic amplitude. The new data may become an input to some theoretical models predicting the energy dependence of the analyzing power

  1. System and method for partial LCVR Stokes polarimeter thermal drift compensation

    Directory of Open Access Journals (Sweden)

    Devlaminck V.

    2010-06-01

    Full Text Available In this paper we deal with the problem of thermal drift when using a LCVR (liquid crystal variable retarder Stokes polarimeter. We address this problem in the restricted case of using a polarimeter to estimate partially linearly polarized light (that corresponds for example to the reflection of an unpolarized incident light on manufactured objects. Usually, the three parameters (S0, S1 and S2 are estimated by observing the reflected light wave, with a CCD sensor, through the LCVR polarimeter. The accuracy of the Stokes parameters estimate is then directly related to precise adjustment of the retardation. The problem is that the retardation introduced by a liquid crystal, variable retarder is strongly dependent on external factors (i.e. temperature. So, it is almost impossible to guarantee the reliability of the retardation in time and in practice it is either necessary to calibrate the LCVR just before carrying out measurement or use a thermostatic control. So, in this paper we propose a solution that does not care about the thermal drift of the LCVR to estimate accurately partially linearly polarized light without thermostatic control.

  2. Education and Outreach Opportunities in New Astronomical Facilities

    Science.gov (United States)

    Mould, J. R.; Pompea, S.

    2002-12-01

    Astronomy presents extraordinary opportunities for engaging young people in science from an early age. The National Optical Astronomy Observatory (NOAO), supported by the National Science Foundation, leverages the attraction of astronomy with a suite of formal and informal education programs that engage our scientists and education and public outreach professionals in effective, strategic programs that capitalize on NOAO's role as a leader in science and in the design of new astronomical facilities. The core of the science education group at NOAO in Tucson consists of a group of Ph.D.-level scientists with experience in educational program management, curriculum and instructional materials development, teacher/scientist partnerships, and teacher professional development. This core group of scientist/educators hybrids has a strong background in earth and space science education as well as experience in working with and teaching about the technology that has enabled new astronomical discoveries. NOAO has a vigorous public affairs/media program and a history of effectively working locally, regionally, and nationally with the media, schools, science centers, and, planetaria. In particular, NOAO has created successful programs exploring how research data and tools can be used most effectively in the classroom. For example, the Teacher Leaders in Research Based Science Education explores how teachers can most effectively integrate astronomical research on novae, active galactic nuclei, and the Sun into classroom-based investigations. With immersive summer workshops at Kitt Peak National Observatory and the National Solar Observatory at Sacramento Peak, teachers learn research and instrumentation skills and how to encourage and maintain research activities in their classrooms. Some of the new facilities proposed in the recent decadal plan, Astronomy and Astrophysics in the New Millennium (National Academy Press), can provide extended opportunities for incorporating

  3. The Undergraduate Research Resources at the Pisgah Astronomical Research Institute

    Science.gov (United States)

    Cline, J. Donald; Castelaz, Michael W.

    2016-01-01

    Pisgah Astronomical Research Institute (PARI), a former NASA tracking station located in western North Carolina, has been offering programs, campus, and instrument use for undergraduate research and learning experiences since 2000. Over these years, PARI has collaborated with universities and colleges in the Southeastern U.S. Sharing its campus with institutions of higher learning is a priority for PARI as part of its mission to "to providing hands-on educational and research opportunities for a broad cross-section of users in science, technology, engineering and math (STEM) disciplines."PARI is a 200 acre campus for environmental, earth, geological, physical, and astronomical sciences. For example, the PARI 26-m and 4.6-m radio telescopes are excellent for teaching electromagnetic theory, spectroscopy, atomic and molecular emission processes, and general physics and astronomy concepts. The PARI campus has lab and office space, data centers with high speed internet, distance learning capabilities, radio and optical telescopes, earth science sensors, housing and cafeteria.Also, the campus is in an excellent spot for environmental and biological sciences lab and classroom experiences for students. The campus has the capability to put power and Internet access almost anywhere on its 200 acre campus so experiments can be set up in a protected area of a national forest. For example, Earthscope operates a Plate Boundary Observatory sensor on campus to measure plate tectonic motion. And, Clemson University has an instrument measuring winds and temperatures in the Thermsophere. The use of thePARI campus is limited only by the creativity faculty to provide a rich educational environment for their students. An overview of PARI will be presented along with a summary of programs, and a summary of undergraduate research experiences over the past 15 years. Access to PARI and collaboration possibilities will be presented.

  4. The Palomar Kernel Phase Experiment: Testing Kernel Phase Interferometry for Ground-based Astronomical Observations

    CERN Document Server

    Pope, Benjamin; Hinkley, Sasha; Ireland, Michael J; Greenbaum, Alexandra; Latyshev, Alexey; Monnier, John D; Martinache, Frantz

    2015-01-01

    At present, the principal limitation on the resolution and contrast of astronomical imaging instruments comes from aberrations in the optical path, which may be imposed by the Earth's turbulent atmosphere or by variations in the alignment and shape of the telescope optics. These errors can be corrected physically, with active and adaptive optics, and in post-processing of the resulting image. A recently-developed adaptive optics post-processing technique, called kernel phase interferometry, uses linear combinations of phases that are self-calibrating with respect to small errors, with the goal of constructing observables that are robust against the residual optical aberrations in otherwise well-corrected imaging systems. Here we present a direct comparison between kernel phase and the more established competing techniques, aperture masking interferometry, point spread function (PSF) fitting and bispectral analysis. We resolve the alpha Ophiuchi binary system near periastron, using the Palomar 200-Inch Telesco...

  5. Balloon UV Experiments for Astronomical and Atmospheric Observations

    CERN Document Server

    Sreejith, A G; Sarpotdar, Mayuresh; Nirmal, K; Ambily, S; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

    2016-01-01

    The ultraviolet (UV) window has been largely unexplored through balloons for astronomy. We discuss here the development of a compact near-UV spectrograph with ?ber optics input for balloon ights. It is a modi?ed Czerny-Turner system built using o?-the-shelf components. The system is portable and scalable to di?erent telescopes. The use of re ecting optics reduces the transmission loss in the UV. It employs an image-intensi?ed CMOS sensor, operating in photon counting mode, as the detector of choice. A lightweight pointing system developed for stable pointing to observe astronomical sources is also discussed, together with the methods to improve its accuracy, e.g. using the in-house build star sensor and others. Our primary scienti?c objectives include the observation of bright Solar System objects such as visible to eye comets, Moon and planets. Studies of planets can give us valuable information about the planetary aurorae, helping to model and compare atmospheres of other planets and the Earth. The other ma...

  6. Young Astronomers' Observe with ESO Telescopes

    Science.gov (United States)

    1995-11-01

    Today, forty 16-18 year old students and their teachers are concluding a one-week, educational `working visit' to the ESO Headquarters in Garching (See ESO Press Release 14/95 of 8 November 1995). They are the winners of the Europe-wide contest `Europe Towards the Stars', organised by ESO with the support of the European Union, under the auspices of the Third European Week for Scientific and Technological Culture. From November 14-20, they have worked with professional ESO astronomers in order to get insight into the methods and principles of modern astronomy and astrophysics, as carried out at one of the world's foremost international centres. This included very successful remote observations with the ESO 3.5-m New Technology Telescope (NTT) and the 1.4-m Coude Auxiliary Telescope (CAT) via a satellite link between the ESO Headquarters and the La Silla observatory in Chile, 12,000 kilometres away. After a general introduction to modern astronomy on the first day of the visit, the participants divided into six teams, according to their interests. Some chose to observe distant galaxies, others prefered to have a closer look on binary stars, and one team decided to investigate a star which is thought to be surrounded by a proto-planetary system. Each team was supported by an experienced ESO astronomer. Then followed the observations at the remote consoles during three nights, the first at the NTT and the following at the CAT. Each team had access to the telescope during half a night. Although the work schedule - exactly as in `real' science - was quite hard, especially during the following data reduction and interpretative phase, all teams managed extremely well and in high spirits. The young astronomers' observations were favoured by excellent atmospheric conditions. At the NTT, the seeing was better than 0.5 arcsecond during several hours, an exceptional value that allows very good images to be obtained. All observations represent solid and interesting science, and

  7. The Focal Plane Package for the Solar Optical Telescope on Solar-B

    Science.gov (United States)

    Tarbell, T. D.

    2005-05-01

    Solar-B is a space science mission of the Japanese Aerospace Exploration Agency (JAXA) and a NASA Solar Terrestrial Probes mission. It includes the 50-cm aperture Solar Optical Telescope (SOT), with its Focal Plane Package (FPP) designed for high resolution photospheric and chromospheric imaging and spectro-polarimetry. There are also two coronal instruments, the X-Ray Telescope and Extreme-ultraviolet Imaging Spectrometer. Solar-B will be launched into a Sun-synchronous polar orbit in August, 2006. The SOT is provided by JAXA and is being built by the National Astronomical Observatory of Japan (NAOJ) and Mitsubishi Electric Co. A team of Lockheed Martin, High Altitude Observatory (HAO), and NAOJ scientists and engineers have built the FPP instrument. This paper gives an overview of the science goals of the FPP as well as the instrument performance characteristics. The primary goal is to understand the coupling between the fine magnetic structures in the photosphere and dynamic processes and heating in the chromosphere and corona. The FPP consists of a narrow-band tunable birefringent filter imager, broad-band interference filter imager, and spectro-polarimeter (SP), essentially a space version of the HAO Advanced Stokes Polarimeter. The image is stabilized by a correlation tracker and active tilt mirror. The SP makes vector magnetic measurements from Stokes spectra of the Fe I lines 630.1 and 630.2 nm, with 0.16 arcsec pixels and field of view up to 164 x 328 arcsec. The broad-band system takes diffraction-limited images (0.05 arcsec pixels) in the Ca II H line, CN and G bandheads, and continuum bands. The narrow-band system makes filtergrams, magnetograms, Dopplergrams, and Stokes images in several photospheric lines, Mg b, Na D, and H-alpha, similar to the SOUP filter at La Palma. It has 0.08 arcsec pixels and field-of-view same as that of the SP. SOT and FPP have been calibrated in great detail and have observed the sun in two end-to-end tests at NAOJ. Sample

  8. An astronomical survey conducted in Belgium

    CERN Document Server

    Naze, Yael

    2013-01-01

    This article presents the results of the first survey conducted in Belgium about the interest and knowledge in astronomy. Two samples were studied, the public at large (667 questionnaires) and students (2589 questionnaires), but the results are generally similar in both samples. We evaluated people's interest, main information source, and attitudes towards astronomy, as well as their supposed and actual knowledge of the subject. The main conclusion is that, despite a poor self-confidence, people do know the basic astronomical concepts. However, that knowledge is not deeply rooted, as reasoning questions show well-spread misconceptions and/or misunderstandings.

  9. American Astronomical Society Honors NRAO Scientist

    Science.gov (United States)

    2005-01-01

    The American Astronomical Society (AAS) has awarded its prestigious George Van Biesbroeck Prize to Dr. Eric Greisen of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico. The society cited Greisen's quarter-century as "principal architect and tireless custodian" of the Astronomical Image Processing System (AIPS), a massive software package used by astronomers around the world, as "an invaluable service to astronomy." Dr. Eric Greisen Dr. Eric Greisen CREDIT: NRAO/AUI/NSF (Click on image for larger version) The Van Biesbroeck Prize "honors a living individual for long-term extraordinary or unselfish service to astronomy, often beyond the requirements of his or her paid position." The AAS, with about 7,000 members, is the major organization of professional astronomers in North America. " The Very Large Array (VLA) is the most productive ground-based telescope in the history of astronomy, and most of the more than 10,000 observing projects on the VLA have depended upon the AIPS software to produce their scientific results," said Dr. James Ulvestad, NRAO's Director of New Mexico Operations. "This same software package also has been the principal tool for scientists using the Very Long Baseline Array and numerous other radio telescopes around the world," Ulvestad added. Greisen, who received a Ph.D in astronomy from the California Institute of Technology, joined the NRAO in 1972. He moved from the observatory's headquarters in Charlottesville, Virginia, to its Array Operations Center in Socorro in 2000. Greisen, who learned of the award in a telephone call from the AAS President, Dr. Robert Kirschner of Harvard University, said, "I'm pleased for the recognition of AIPS and also for the recognition of the contributions of radio astronomy to astronomy as a whole." He added that "it wasn't just me who did AIPS. There were many others." The AIPS software package grew out of the need for an efficient tool for producing images with the VLA, which was being

  10. Division XII: Commission 6: Astronomical Telegrams

    Science.gov (United States)

    Samus, N. N.; Yamaoka, H.; Gilmore, A. C.; Aksnes, K.; Green, D. W. E.; Marsden, B. G.; Nakano, S.; Lara, Martin; Pitjeva, Elena V.; Sphar, T.; Ticha, J.; Williams, G.

    2015-08-01

    IAU Commission 6 ``Astronomical Telegrams'' had a single business meeting during the Beijing General Assembly of the IAU. It took place on Friday, August 24, 2012. The meeting was attended by five C6 members (N. N. Samus; D. W. E. Green; S. Nakano; J. Ticha; and H. Yamaoka). Also present was Prof. F. Genova as a representative of the IAU Division B. She told the audience about the current restructuring of IAU Commissions and Divisions and consequences for the future of C6.

  11. Le Verrier magnificent and detestable astronomer

    CERN Document Server

    Lequeux, James

    2013-01-01

    Le Verrier was a superb scientist. His discovery of Neptune in 1846 made him the most famous astronomer of his time. He produced a complete theory of the motions of the planets which served as a basis for planetary ephemeris for a full century. Doing this, he discovered an anomaly in the motion of Mercury which later became the first proof of General Relativity. He also founded European meteorology. However his arrogance and bad temper created many enemies, and he was even fired from his position of Director of the Paris Observatory.

  12. The astronomical revolution Copernicus, Kepler, Borelli

    CERN Document Server

    Koyre, Alexandre

    2013-01-01

    Originally published in English in 1973. This volume traces the development of the revolution which so drastically altered man's view of the universe in the sixteenth and seventeenth centuries. The ""astronomical revolution"" was accomplished in three stages, each linked with the work of one man. With Copernicus, the sun became the centre of the universe. With Kepler, celestial dynamics replaced the kinematics of circles and spheres used by Copernicus. With Borelli the unification of celestial and terrestrial physics was completed by abandonment of the circle in favour the straight line to inf

  13. Beam Test of a Prototype Detector Array for the PoGO Astronomical Hard X-Ray/Soft Gamma-Ray Polarimeter

    CERN Document Server

    Mizuno, T; Ng, J S T; Tajima, H; Mitchell, J W; Streitmatter, R E; Fernholz, R C; Groth, E; Fukazawa, Y

    2005-01-01

    Polarization measurements in the X-ray and gamma-ray energy range can provide crucial information on massive compact objects such as black holes and neutron stars. The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne instrument designed to measure polarization from astrophysical objects in the 30-100 keV range, under development by an international collaboration with members from United States, Japan, Sweden and France. To examine PoGO's capability, a beam test of a simplified prototype detector array was conducted at the Argonne National Laboratory Advanced Photon Source. The detector array consisted of seven plastic scintillators, and was irradiated by polarized photon beams at 60, 73, and 83 keV. The data showed a clear polarization signal, with a measured modulation factor of $0.42 \\pm 0.01$. This was successfully reproduced at the 10% level by the computer simulation package Geant4 after modifications to its implementation of polarized Compton/Rayleigh scattering. Details of the beam test and t...

  14. InnoPOL: an EMCCD imaging polarimeter and 85-element curvature AO system on the 3.6-m AEOS telescope for cost effective polarimetric speckle suppression

    CERN Document Server

    Harrington, David; Chun, Mark; Ftaclas, Christ; Gisler, Daniel; Kuhn, Jeff

    2016-01-01

    The Hokupa'a-85 curvature adaptive optics system components have been adapted to create a new AO-corrected coud\\'{e} instrument at the 3.67m Advanced Electro-Optical System (AEOS) telescope. This new AO-corrected optical path is designed to deliver an f/40 diffraction-limited focus at wavelengths longer than 800nm. A new EMCCD-based dual-beam imaging polarimeter called InnoPOL has been designed and is presently being installed behind this corrected f/40 beam. The InnoPOL system is a flexible platform for optimizing polarimetric performance using commercial solutions and for testing modulation strategies. The system is designed as a technology test and demonstration platform as the coud\\'{e} path is built using off-the-shelf components wherever possible. Models of the polarimetric performance after AO correction show that polarization modulation at rates as slow as 200Hz can cause speckle correlations in brightness and focal plane location sufficient enough to change the speckle suppression behavior of the mod...

  15. Relativistic scaling of astronomical quantities and the system of astronomical units

    Science.gov (United States)

    Klioner, S. A.

    2008-02-01

    Context: For relativistic modeling of high-accuracy astronomical data, several time scales are used: barycentric and geocentric coordinate times (TCB and TCG) and two additional time scales (TDB and TT), which are defined as linear functions of TCB and TCG, respectively. Aims: The paper is devoted to a concise, but still detailed, explanation of the reasons and the implications of the relativistic scalings of astronomical quantities induced by the time scales TDB and TT. Methods: We consequently distinguish between quantities and their numerical values expressed in some units. Results: It is argued that the scaled time scales, the scaled spatial coordinates, and the scaled masses should be considered as distinct quantities that can be expressed themselves in any units and not as numerical values of the same quantities expressed in some different, non-SI units (“TDB units” and “TT units”). Along the same lines, the system of astronomical units is discussed in the relativistic framework. The whole freedom in the definitions of the systems of astronomical units for TCB and TDB is demonstrated. A number of possible ways to freeze the freedom are shown and discussed. It is argued that in the future one should think about converting AU into a defined quantity by fixing its value in SI meters.

  16. Care of astronomical telescopes and accessories a manual for the astronomical observer and amateur telescope maker

    CERN Document Server

    Pepin, M Barlow

    2006-01-01

    This is complete guide for anyone who wants to understand more than just the basics of astronomical telescopes and accessories, and how to maintain them in the peak of condition. The latest on safely adjusting, cleaning, and maintaining your equipment is combined with thoroughly updated methods from the old masters.

  17. Staring/focusing lobster-eye hard x-ray imaging for non-astronomical objects

    Science.gov (United States)

    Gertsenshteyn, Michael; Jannson, Tomasz; Savant, Gajendra

    2005-08-01

    A new approach to hard X-ray imaging is proposed, based on staring optics consisting of a lobster-eye lens. This new Staring Imaging Lobster-Eye X-Ray approach is especially suited to X-ray lobster-eye imaging of non-astronomical objects at finite distances, because the staring optics replacing the standard scanning optics, result in an extremely efficient power budget, making possible not only the use of low-efficiency Compton backscattering but also operation with low-flux X-ray beams, increasing operator safety. The lobster-eye optics, consisting of square-cross-section microchannels, transmit an X-ray beam by total external reflection. This mode of operation has already been verified for viewing astronomical objects. Its major challenge is minimizing image defocusing by apodization. For this purpose, a new lens imaging equation is derived, and a new local optical axis concept is defined. Applications include medical imaging, cargo inspection, non-destructive testing, industrial and security safeguards, and surveillance.

  18. Astronomers Make First Images With Space Radio Telescope

    Science.gov (United States)

    1997-07-01

    from orbiting radio telescopes. "We would be skeptical of a complex image if we had not been able to obtain a good point image first," Romney added. A second observing target, the quasar 1156+295, observed on June 5, made a more interesting picture. Seen by ground-based radio observatories, this object, at a distance of 6.5 billion light years, has been known to show an elongation in its structure to the northeast of the core. However, seen with the space-ground system, it is clearly shown to have both a core and a complex "jet" emerging from the core. Such jets, consisting of subatomic particles moving near the speed of light, are seen in many quasars and active galaxies throughout the universe. In fact, 1156+295 is one of a class of objects recently found by NASA's Compton Gamma-Ray Observatory to exhibit powerful gamma-ray emission; such objects are among the most compact and energetic known in the universe. "By showing that this object actually is a core-jet system, HALCA has produced its first new scientific information, and demonstrates its imaging capabilities for a variety of astrophysical investigations," Romney said. "This image shows that the jet extends much closer to the core, or 'central engine' of the quasar than is shown by ground-only imaging," Romney added. "This is an exciting and historical achievement for radio astronomy," said Miller Goss, NRAO's VLA/VLBA Director. "At NRAO, we have seen our colleagues -- scientists, electrical engineers, computer programmers and technicians in Socorro and Green Bank -- work for years on this project. Now, they can take pride in their success." Radio astronomers, like astronomers using visible light, usually seek to make images of the objects at which they aim their telescopes. Because radio waves are much longer than light waves, a radio telescope must be much larger than an optical instrument in order to see the same amount of detail. Greater ability to see detail, called resolving power, has been a quest of

  19. Sketching the moon an astronomical artist's guide

    CERN Document Server

    Handy, Richard; McCague, Thomas; Rix, Erika; Russell, Sally

    2012-01-01

    Soon after you begin studying the sky through your small telescope or binoculars, you will probably be encouraged by others to make sketches of what you see. Sketching is a time-honored tradition in amateur astronomy and dates back to the earliest times, when telescopes were invented. Even though we have lots of new imaging technologies nowadays, including astrophotography, most observers still use sketching to keep a record of what they see, make them better observers, and in hopes of perhaps contributing something to the body of scientific knowledge about the Moon. Some even sketch because it satisfies their artistic side. The Moon presents some unique challenges to the astronomer-artist, the Moon being so fond of tricks of the light. Sketching the Moon: An Astronomical Artist’s Guide, by five of the best lunar observer-artists working today, will guide you along your way and help you to achieve really high-quality sketches. All the major types of lunar features are covered, with a variety of sketching te...

  20. Powerful Radio Burst Indicates New Astronomical Phenomenon

    Science.gov (United States)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  1. Digitization of Archives of Astronomical Plates

    Science.gov (United States)

    Omizzolo, Alessandro; Cesare, Barbieri; Blanco, Carlo; Bucciarelli, Beatrice; di Paola, Andrea; Nesci, Roberto

    The photographic plate archives of telescopes around the world contain a veritable treasury of astronomical data. Unfortunately the emulsion is a volatile support and full exploitation of the scientific content is more and more difficult. A large-scale two-year project to digitize the archive of plates of the Italian Astronomical Observatories and of the Specola Vaticana has been started in 2002 with funds from the Ministry of the University and Research following a pilot program funded by the University of Padova in 2001. Identical systems composed by a high quality commercial scanner plus dedicated personal computers and acquisition software (developed initially at DLR Berlin) have been installed in all participating Institutes. Three main goals make up the total project: to provide high quality photometric sequences with the Campo Imperatore telescopes to be used on the scanned plates to perform astrometric measures taking advantage of the large span of time covered by the plates and to distribute the digitized information to all interested researchers via the international Web. This paper presents some of the activities carried out and results obtained so far

  2. Automated object detection for astronomical images

    Science.gov (United States)

    Orellana, Sonny; Zhao, Lei; Boussalis, Helen; Liu, Charles; Rad, Khosrow; Dong, Jane

    2005-10-01

    Sponsored by the National Aeronautical Space Association (NASA), the Synergetic Education and Research in Enabling NASA-centered Academic Development of Engineers and Space Scientists (SERENADES) Laboratory was established at California State University, Los Angeles (CSULA). An important on-going research activity in this lab is to develop an easy-to-use image analysis software with the capability of automated object detection to facilitate astronomical research. This paper presented a fast object detection algorithm based on the characteristics of astronomical images. This algorithm consists of three steps. First, the foreground and background are separated using histogram-based approach. Second, connectivity analysis is conducted to extract individual object. The final step is post processing which refines the detection results. To improve the detection accuracy when some objects are blocked by clouds, top-hat transform is employed to split the sky into cloudy region and non-cloudy region. A multi-level thresholding algorithm is developed to select the optimal threshold for different regions. Experimental results show that our proposed approach can successfully detect the blocked objects by clouds.

  3. Powerful Radio Burst Indicates New Astronomical Phenomenon

    Science.gov (United States)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  4. Conducting Original, Hands-On Astronomical Research in the Classroom

    Science.gov (United States)

    Corneau, M. J.

    2009-12-01

    teachers to convey moderately complex computer science, optical, geographic, mathematical, informational and physical principles through hands-on telescope operations. In addition to the general studies aspects of classroom internet-based astronomy, Tzec Maun supports real science by enabling operators precisely point telescopes and acquire extremely faint, magnitude 19+ CCD images. Thanks to the creative Team of Photometrica (photometrica.org), my teams now have the ability to process and analyze images online and produce results in short order. Normally, astronomical data analysis packages cost greater than thousands of dollars for single license operations. Free to my team members, Photometrica allows students to upload their data to a cloud computing server and read precise photometric and/or astrometric results. I’m indebted to Michael and Geir for their support. The efficacy of student-based research is well documented. The Council on Undergraduate Research defines student research as, "an inquiry or investigation conducted by an undergraduate that makes an original intellectual or creative contribution to the discipline." (http://serc.carleton.edu/introgeo/studentresearch/What. Teaching from Tzec Maun in the classroom is the most original teaching research I can imagine. I very much look forward to presenting this program to the convened body.

  5. Progress on the New York State Observatory: a new 12-meter astronomical telescope

    Science.gov (United States)

    Sebring, T.; O'Dea, C.; Baum, S.; Teran, J.; Loewen, N.; Stutzki, C.; Egerman, R.; Bonomi, G.

    2014-07-01

    Over the past two years, the New York Astronomical Corporation (NYAC), the business arm of the Astronomical Society of New York (ASNY), has continued planning and technical studies toward construction of a 12-meter class optical telescope for the use of all New York universities and research institutions. Four significant technical studies have been performed investigating design opportunities for the facility, the dome, the telescope optics, and the telescope mount. The studies were funded by NYAC and performed by companies who have provided these subsystems for large astronomical telescopes in the past. In each case, innovative and cost effective approaches were identified, developed, analyzed, and initial cost estimates developed. As a group, the studies show promise that this telescope could be built at historically low prices. As the project continues forward, NYAC intends to broaden the collaboration, pursue funding, to continue to develop the telescope and instrument designs, and to further define the scientific mission. The vision of a historically large telescope dedicated to all New York institutions continues to grow and find new adherents.

  6. Astronomical observation devices CIAO and COMICS for Telescope Subaru; Sugbaru boenkyo kansoku sochi CIAO/COMICS

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-20

    Described herein are astronomical observation devices, a coronagraph imaging device (CIAO) and intermediate-infrared imaging spectrometer (COMICS), delivered to National Astronomical Observatory in October 1999. These devices are for the focal section of Telescope Subaru, completed in Hawaii in 1999 (devices for the first stage project), to observe various celestial objects by imaging and spectroscopically processing the infrared ray data collected by the telescope. This company has developed these devices jointly with National Astronomical Observatory as the orderer. They have been in service since December 1999 when they were set in the telescope (the attached photograph shows COMICS). Its major specifications are dimensions: 2,000 mm long, 2,000 mm wide and 1900 mm high, weight: 1,300 kg (CIAO) and 1640 kg (COMICS), and detector temperature: 35K (-238 degrees C) for CIAO and 5K (-268 degrees C) for COMICS. They are featured by the infrared sensor and optical system cooled by a system which uses a refrigerator to prevent heat radiation (infrared ray) from the ambient; and the optical system being insulated and supported by a tension strap structure to keep its performance unaffected by cooling or slanting ({+-}70 degrees). (translated by NEDO)

  7. Angular Resolution of a Photoelectric Polarimeter in the Focus of an Optical System

    OpenAIRE

    Lazzarotto, Francesco; Fabiani, Sergio; Costa, Enrico; Muleri, Fabio; Soffitta, Paolo; Di Cosimo, Sergio; Di Persio, Giuseppe; Rubini, Alda; Bellazzini, Ronaldo; Brez, Alessandro; Spandre, Gloria; Cotroneo, Vincenzo; Moretti, Alberto; Pareschi, Giovanni; Tagliaferri, Giampiero

    2009-01-01

    The INFN and INAF Italian research institutes developed a space-borne X-Ray polarimetry experiment based on a X-Ray telescope, focussing the radiation on a Gas Pixel Detector (GPD). The instrument obtains the polarization angle of the absorbed photons from the direction of emission of the photoelectrons as visualized in the GPD. Here we will show how we compute the angular resolution of such an instrument.

  8. Grid-Enabled Interactive Data Language for Astronomical Data Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Grid technologies provide a valuable solution for data intensive scientific applications but are not readily available for astronomical data and Interactive Data...

  9. The First Astronomical Observatory in Cluj-Napoca

    Science.gov (United States)

    Szenkovits, Ferenc

    2008-09-01

    One of the most important cities of Romania is Cluj-Napoca (Kolozsvár, Klausenburg). This is a traditional center of education, with many universities and high schools. From the second half of the 18th century the University of Cluj has its own Astronomical Observatory, serving for didactical activities and scientific researches. The famous astronomer Maximillian Hell was one of those Jesuits who put the base of this Astronomical Observatory. Our purpose is to offer a short history of the beginnings of this Astronomical Observatory.

  10. Progress toward a Soft X-ray Polarimeter

    CERN Document Server

    Marshall, Herman L; Remlinger, Brian; Gentry, Eric S; Windt, David L; Gullikson, Eric M

    2013-01-01

    We are developing instrumentation for a telescope design capable of measuring linear X-ray polarization over a broad-band using conventional spectroscopic optics. Multilayer-coated mirrors are key to this approach, being used as Bragg reflectors at the Brewster angle. By laterally grading the multilayer mirrors and matching to the dispersion of a spectrometer, one may take advantage of high multilayer reflectivities and achieve modulation factors over 50% over the entire 0.2-0.8 keV band. We present progress on laboratory work to demonstrate the capabilities of an existing laterally graded multilayer coated mirror pair. We also present plans for a suborbital rocket experiment designed to detect a polarization level of 12-17% for an active galactic nucleus in the 0.1-1.0 keV band.

  11. A photoelastic-modulator-based motional Stark effect polarimeter for ITER that is insensitive to polarized broadband background reflections

    Science.gov (United States)

    Thorman, A.; Michael, C.; De Bock, M.; Howard, J.

    2016-07-01

    A motional Stark effect polarimeter insensitive to polarized broadband light is proposed. Partially polarized background light is anticipated to be a significant source of systematic error for the ITER polarimeter. The proposed polarimeter is based on the standard dual photoelastic modulator approach, but with the introduction of a birefringent delay plate, it generates a sinusoidal spectral filter instead of the usual narrowband filter. The period of the filter is chosen to match the spacing of the orthogonally polarized Stark effect components, thereby increasing the effective signal level, but resulting in the destructive interference of the broadband polarized light. The theoretical response of the system to an ITER like spectrum is calculated and the broadband polarization tolerance is verified experimentally.

  12. $\\mathtt{ComEst}$: a Completeness Estimator of Source Extraction on Astronomical Imaging

    CERN Document Server

    Chiu, I-Non; Liu, Jiayi

    2016-01-01

    The completeness of source detection is critical for analyzing the photometric and spatial properties of the population of interest observed by astronomical imaging. We present a software package $\\mathtt{ComEst}$, which calculates the completeness of source detection on charge-coupled device (CCD) images of astronomical observations, especially for the optical and near-infrared (NIR) imaging of galaxies and point sources. The completeness estimator $\\mathtt{ComEst}$ is designed for the source finder $\\mathtt{SExtractor}$ used on the CCD images saved in the Flexible Image Transport System (FITS) format. Specifically, $\\mathtt{ComEst}$ estimates the completeness of the source detection by deriving the detection rate of synthetic point sources and galaxies simulated on the observed CCD images. In order to capture any observational artifacts or noise properties while deriving the completeness, $\\mathtt{ComEst}$ directly carries out the detection of simulated sources on the observed images. Given an observed CCD ...

  13. The 2006 SPIE Symposium on Astronomical Telescopes and Instrumentation ? Observing the Universe from Ground and Space

    Science.gov (United States)

    Moorwood, A.

    2006-06-01

    The most recent of these biennial SPIE (The International Society for Optical Engineering) Symposia was held from 24-31 May in the Orlando World Center Marriott Resort & Convention Center in Florida, USA. Over the last decade, these meetings have grown to become the main forum for presenting and discussing all aspects of ground-based, airborne and space telescopes and their instrumentation, including associated advances in technology, software, operations and even astronomical results. As a consequence the meetings are large and well attended by people at all levels in the process of initiating, approving, implementing and operating astronomical projects and facilities. This year there were ~ 1700 registered participants who presented ~ 1600 papers and posters in the following 12 parallel conferences which formed the heart of the meeting.

  14. Identification of Potential Sites for Astronomical Observations in Northern South-America

    CERN Document Server

    Pinzón, G; Hernández, J

    2015-01-01

    In this study we describe an innovative method to determine potential sites for optical and infrared astronomical observations in the Andes region of northern South America. The method computes the Clear sky fraction (CSF) from Geostationary Observational Environmental Satellite (GOES) data for the years 2008-12 through a comparison with temperatures obtained from long-term records of weather stations and atmospheric temperature profiles from radiosonde. Criteria for sky clearance were established for two infrared GOES channels in order to determine potential sites in the Andes region of northern South-America. The method was validated using the reported observed hours at Observatorio Nacional de Llano del Hato in Venezuela. Separate CSF percentages were computed for dry and rainy seasons for both, photometric and spectroscopic night qualities. Twelve sites with five year averages of CSF for spectroscopic nights larger than 30% during the dry seasons were found to be suitable for astronomical observations. Th...

  15. Established Designs For Advanced Ground Based Astronomical Telescopes In The 1-meter To 4-meter Domain

    Science.gov (United States)

    Hull, Anthony B.; Barentine, J.; Legters, S.

    2012-01-01

    The same technology and analytic approaches that led to cost-effective unmitigated successes for the spaceborne Kepler and WISE telescopes are now being applied to meter-class to 4-meter-class ground telescopes, providing affordable solutions to ground astronomy, with advanced features as needed for the application. The range of optical and mechanical performance standards and features that can be supplied for ground astronomy shall be described. Both classical RC designs, as well as unobscured designs are well represented in the IOS design library, allowing heritage designs for both night time and day time operations, the latter even in the proximity of the sun. In addition to discussing this library of mature features, we will also describe a process for working with astronomers early in the definition process to provide the best-value solution. Solutions can include remote operation and astronomical data acquisition and transmission.

  16. Big Data analytics and Cognitive Computing: future opportunities for Astronomical research

    CERN Document Server

    Garrett, Michael

    2014-01-01

    The days of the lone astronomer with his optical telescope and photographic plates are long gone: Astronomy in 2025 will not only be multi-wavelength, but multi-messenger, and dominated by huge data sets and matching data rates. Catalogues listing detailed properties of billions of objects will in themselves require a new industrial-scale approach to scientific discovery, requiring the latest techniques of advanced data analytics and an early engagement with the first generation of cognitive computing systems. Astronomers have the opportunity to be early adopters of these new technologies and methodologies: the impact can be profound and highly beneficial to effecting rapid progress in the field. Areas such as SETI research might favourably benefit from cognitive intelligence that does not rely on human bias and preconceptions.

  17. ISO Results Presented at International Astronomical Union

    Science.gov (United States)

    1997-08-01

    Some of the work being presented is collected in the attached ESA Information Note N 25-97, ISO illuminates our cosmic ancestry. A set of six colour images illustrating various aspects have also been released and are available at http://www.estec.esa.nl/spdwww/iso1808.htm or in hard copy from ESA Public Relations Paris (fax:+33.1.5369.7690). These pictures cover: 1. Distant but powerful infrared galaxies 2. A scan across the milky way 3. Helix nebula: the shroud of a dead star 4. Supernova remnant Cassiopeia A 5. Trifid nebula: a dusty birthplace of stars 6. Precursors of stars and planets The International Astronomical Union provides a forum where astronomers from all over the world can develop astronomy in all its aspects through international co-operation. General Assemblies are held every three years. It is expected that over 1600 astronomers will attend this year's meeting, which is being held in Kyoto, Japan from 18-30 August. Further information on the meeting can be found at: www.tenmon.or.jp/iau97/ . ISO illuminates our cosmic ancestry The European Space Agency's Infrared Space Observatory, ISO, is unmatched in its ability to explore and analyse many of the universal processes that made our existence possible. We are children of the stars. Every atom in our bodies was created in cosmic space and delivered to the Sun's vicinity in time for the Earth's formation, during a ceaseless cycle of birth, death and rebirth among the stars. The most creative places in the sky are cool and dusty, and opaque even to the Hubble Space Telescope. Infrared rays penetrating the dust reveal to ISO hidden objects, and the atoms and molecules of cosmic chemistry. "ISO is reading Nature's recipe book," says Roger Bonnet, ESA's director of science. "As the world's only telescope capable of observing the Universe over a wide range of infrared wavelengths, ISO plays an indispensable part in astronomical discoveries that help to explain how we came to exist." This Information Note

  18. Upgraded photon calorimeter with integrating readout for the Hall A Compton polarimeter at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Friend, M., E-mail: mfriend@andrew.cmu.edu [Carnegie Mellon University, Department of Physics, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States); Parno, D. [Carnegie Mellon University, Department of Physics, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States); University of Washington, Center for Experimental Nuclear Physics and Astrophysics and Department of Physics, Seattle, WA 98195 (United States); Benmokhtar, F. [Carnegie Mellon University, Department of Physics, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States); Christopher Newport University, Department of Physics, Computer Science and Engineering, 1 University Place, Newport News, VA 23606 (United States); Camsonne, A. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave, Newport News, VA 23606 (United States); Dalton, M.M. [University of Virginia, Department of Physics, 382 McCormick Rd, Charlottesville, VA 22904 (United States); Franklin, G.B.; Mamyan, V. [Carnegie Mellon University, Department of Physics, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States); Michaels, R.; Nanda, S. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave, Newport News, VA 23606 (United States); Nelyubin, V.; Paschke, K. [University of Virginia, Department of Physics, 382 McCormick Rd, Charlottesville, VA 22904 (United States); Quinn, B. [Carnegie Mellon University, Department of Physics, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States); Rakhman, A.; Souder, P. [Syracuse University, Department of Physics, Syracuse, NY 13244 (United States); Tobias, A. [University of Virginia, Department of Physics, 382 McCormick Rd, Charlottesville, VA 22904 (United States)

    2012-06-01

    The photon arm of the Compton polarimeter in Hall A of Jefferson Lab has been upgraded to allow for electron beam polarization measurements with better than 1% accuracy. The data acquisition (DAQ) system now includes an integrating mode, which eliminates several systematic uncertainties inherent in the original counting-DAQ setup. The photon calorimeter has been replaced with a Ce-doped Gd{sub 2}SiO{sub 5} crystal, which has a bright output and fast response, and works well for measurements using the new integrating method at electron beam energies from 1 to 6 GeV.

  19. Upgraded photon calorimeter with integrating readout for Hall A Compton Polarimeter at Jefferson Lab

    CERN Document Server

    Friend, M; Benmokhtar, F; Camsonne, A; Dalton, M; Franklin, G B; Mamyan, V; Michaels, R; Nanda, S; Nelyubin, V; Paschke, K; Quinn, B; Rakhman, A; Souder, P; Tobias, A

    2011-01-01

    The photon arm of the Compton polarimeter in Hall A of Jefferson Lab has been upgraded to allow for electron beam polarization measurements with better than 1% accuracy. The data acquisition system (DAQ) now includes an integrating mode, which eliminates several systematic uncertainties inherent in the original counting-DAQ setup. The photon calorimeter has been replaced with a Ce-doped GSO crystal, which has a bright output and fast response, and works well for measurements using the new integrating method at electron beam energies from 1 to 6 GeV.

  20. Imaging molecular structure with Stokes-polarimeter based second harmonic generation microscopy

    Science.gov (United States)

    Mazumder, Nirmal; Qiu, Jianjun; Hu, Chih-Wei; Kao, Fu-Jen

    2013-02-01

    We analyzed the polarization states of second harmonic generation (SHG) signals from starch granules and type I collagen through a four-channel photon counting based Stokes-polarimeter. The 2D SHG images of samples are reconstructed using various polarization parameters, such as the degree of polarization (DOP), the degree of linear polarization (DOLP), the degree of circular polarization (DOCP), as well as the anisotropy from the acquired Stokes parameters. Furthermore, we have demonstrated that the polarization parameters are changes at different input polarizations and focusing depths.

  1. Laser polarimeter LP101M and its applications in liquid cromatography

    Science.gov (United States)

    Fajer, V.; Rodriguez, C.; Gonzalez, R.; Cossio, G.; Martinez, M.; Bravo, O.

    1996-02-01

    A high sensitivity laser polarimeter LP101M employing a He-Ne laser has been designed and constructed as a detector for liquid chromatography achieving a sensitivity better than 0.001 degree. The operation principle and technical characteristics of this instrument are described. A liquid gel chromatography column system suitable for sugar cane juice analysis was also designed and calibrated. It separated and analyzed the medium molecular weight carbohydrates and demonstrated the strong influence of these substances in the conventional polarimetric determinations.

  2. Design and tests of the hard X-ray polarimeter X-Calibur

    Energy Technology Data Exchange (ETDEWEB)

    Beilicke, M., E-mail: beilicke@physics.wustl.edu [Washington University, St. Louis, MO (United States); Baring, M.G. [Rice University, TX (United States); Barthelmy, S. [Goddard Space Flight Center, MD (United States); Binns, W.R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q. [Washington University, St. Louis, MO (United States); Haba, Y. [Nagoya University (Japan); Israel, M.H. [Washington University, St. Louis, MO (United States); Kunieda, H. [Nagoya University (Japan); Lee, K. [Washington University, St. Louis, MO (United States); Matsumoto, H.; Miyazawa, T. [Nagoya University (Japan); Okajima, T.; Schnittman, J. [Goddard Space Flight Center, MD (United States); Tamura, K. [Nagoya University (Japan); Tueller, J. [Goddard Space Flight Center, MD (United States); Krawczynski, H. [Washington University, St. Louis, MO (United States)

    2012-11-11

    X-ray polarimetry will give qualitatively new information about high-energy astrophysical sources. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC{mu}S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10-80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

  3. Measurement of low energy longitudinal polarised positron beams via a Bhabha polarimeter

    CERN Document Server

    Alexander, G; Alexander, Gideon; Reinherz-Aronis, Erez

    2005-01-01

    The introduction of a longitudinal polarised positron beam in an $e^+e^-$ linear collider calls for its polarisation monitoring and measurement at low energies near its production location. Here it is shown that a relatively simple Bhabha scattering polarimeter allows, at energies below 5000 MeV, a more than adequate positron beam longitudinal polarisation measurement by using only the final state electrons. It is further shown that out of the three, 10, 250 or 5000 MeV positron beam energy locations, where the polarisationmeasurement in the TESLA linear collider can be performed, the 250 MeV site is best suited for this task.

  4. Parity of the band head at 3710 keV in 99Rh using clover detector as Compton polarimeter

    Indian Academy of Sciences (India)

    R Palit; H C Jain; P K Joshi; S Nagaraj; B V T Rao; S N Chintalapudi; S S Ghugre

    2000-03-01

    Clover detector has been used as a Compton polarimeter to measure the linear polarization of -rays produced in heavy ion fusion reaction. The polarization sensitivity of the clover detector has been measured over -ray energies ranging from 386 to 1368 keV. The E1 multipolarity of the 1117 keV transition in 99Rh has been established using this polarimeter. This has resulted in the assignment of negative parity to the band head at 3710 keV in 99Rh.

  5. Young astronomer in Denmark 1946 to 1958

    CERN Document Server

    Høg, Erik

    2015-01-01

    This is a personal account of how I became an astronomer. Fascinated by the stars and planets in the dark sky over Lolland, an island 100 km south of Copenhagen, the interest in astronomy was growing. Encouraged by my teachers, I polished mirrors and built telescopes with generous help from the local blacksmith and I observed light curves of variable stars. Studies at the Copenhagen University from 1950 gradually led me deeper into astronomy, especially astrometry (the astronomy of positions), guided by professor Bengt Str\\"omgren and my mentor dr. phil. Peter Naur. I was lucky to take part in the buildup of the new observatory at Brorfelde during the first difficult years and the ideas I gathered there have contributed to the two astrometry satellites Hipparcos and Gaia launched by the European Space Agency (ESA) in respectively 1989 and 2013.

  6. Thirty years of astronomical discovery with UKIRT

    CERN Document Server

    Davies, John; Robson, Ian; The Scientific Achievement of the United Kingdom InfraRed Telescope

    2013-01-01

    These are the proceedings of an international meeting hosted by the Royal Observatory, Edinburgh, to commemorate the 30th anniversary of the dedication of the UKIRT, the United Kingdom InfraRed Telescope. The volume comprises 31 professional level papers. The first part of the book has 10 thorough reviews of the conception, design and build of the telescope, as well as accounts of some its key instruments such as IRCAM (the common-user infrared camera), CGS4 (the fourth Cooled Grating Spectrometer) and the Wide Field Camera. The second part of the book comprises 14 reviews of scientific achievements during its twenty years of visitor mode operations. The final part of the book is a series of 7 reviews of the results from the multiple surveys being done as part of UKIDSS (UKIRT Infrared Deep Sky Survey). The authors are all experts in their respective fields, for example instrument scientists, operations staff and leading astronomers.

  7. Library & Information Services as Astronomer's Wishlist

    CERN Document Server

    Andernach, H

    1998-01-01

    I review some of the past and current methods for retrieval of literature and other published information, excluding commercial services. Much of this is a personal view and based on experience made at various institutions, some of them neither with an adequately complete astronomy library, nor with a professional astronomy librarian. Rather than describing current retrieval methods, a few of their weaknesses are identified which merit future improval. Despite the availability of powerful electronic tools, we need to improve efforts in safeguarding published numerical and textual information in a format readily usable by astronomers. Comments are made on a user-friendly arrangement of a library, and on useful tasks for librarians with available time.

  8. Bonaparte and the astronomers of Brera Observatory

    CERN Document Server

    Antonello, E

    2014-01-01

    In Northern Italy, between 1796 and 1814, Napoleon Bonaparte formed a Republic, and then a Kingdom, controlled by France. Milan was the capital of the State, and the Brera Palace was the main cultural centre, as regards both the arts and the sciences. Bonaparte probably intended to strengthen this characteristic of Brera, aiming at increasing its Italian and European relevance. We will discuss in detail in which way he interacted with the astronomers of Brera Observatory, and in particular with Barnaba Oriani, that was considered the local main representative of the 'republique des lettres', that is, the world of literature, arts and sciences. We propose a possible reconstruction of the effects of those complicated historical events on the Italian astronomy and on its relations with the European one.

  9. Die Gerling Sternwarte (Gerling Astronomical Observatory)

    CERN Document Server

    Schrimpf, Andreas

    2015-01-01

    Christian Ludwig Gerling's 1817 appointment as Professor for Mathematics, Physics and Astronomy resulted in the foundation of the Mathematical and Physical Institute of the Philipps University. In 1838, Gerling moved onto new premises in the main building of the former D\\"ornberger Hof in Renthof Street where the Philipps University's astronomical observatory was installed in the upper part of the old tower in 1841. The most important device at that time was a transit instrument which served to measure the transit times of stars in the meridian. Precise alignment required the use of a meridian stone, an artificial point of reference exactly north of and at about four kilometers' distance from the observatory. The scientists observed planets and their moons, the asteroids that were only discovered at the beginning of the 19th century, and some fainter stars in order to improve stellar charts. The Gerling Observatory is the first place in Hesse, where positions of asteroids were read.

  10. Astronomical research at the Hopkins PHOENIX Observatory

    Science.gov (United States)

    Hopkins, J. L.

    1985-09-01

    After trying astrophotography and radio astronomy it was decided that the best way to do meaningful astronomical research at a small private observatory was by doing photoelectric photometry. Having the observatory located in the back yard of a private residence affors the luxury of observing any time the sky conditions permit. Also modest equipment is all that is needed to do accurate UBV photometry of stars 8th magnitude and brighter. Since beginning in 1980 the Hopkins Phoenix Observatory has published papers on several RS CVn star systems, 31 Cygni, 22 Vul, 18 Tau Per, and has followed the 1982-1984 eclipse of Epsilon Aurigae from its start to the present with over 1000 UBV measurements. In addition the Hopkins Phoenix Observatory has developed several pieces of photometry equipment including the HPO PEPH-101 photometer head and photon counting electronics.

  11. AstroVis: Visualizing astronomical data cubes

    Science.gov (United States)

    Finniss, Stephen; Tyler, Robin; Questiaux, Jacques

    2016-08-01

    AstroVis enables rapid visualization of large data files on platforms supporting the OpenGL rendering library. Radio astronomical observations are typically three dimensional and stored as data cubes. AstroVis implements a scalable approach to accessing these files using three components: a File Access Component (FAC) that reduces the impact of reading time, which speeds up access to the data; the Image Processing Component (IPC), which breaks up the data cube into smaller pieces that can be processed locally and gives a representation of the whole file; and Data Visualization, which implements an approach of Overview + Detail to reduces the dimensions of the data being worked with and the amount of memory required to store it. The result is a 3D display paired with a 2D detail display that contains a small subsection of the original file in full resolution without reducing the data in any way.

  12. Simon Newcomb: America's Unofficial Astronomer Royal

    Science.gov (United States)

    Graham, John

    2007-10-01

    Bill Carter and Merri Sue Carter Mantazas; xiii + 213 pp.; ISBN 1-59113-803-5 2006; $26.95 This book introduced me to a commanding figure in American science from the late nineteenth century: Simon Newcomb. Newcomb has been called the nineteenth-century equivalent of Carl Sagan and Albert Einstein. He rose from humble beginnings to be the preeminent American astronomer of his generation. He made basic, far-reaching, and enduring contributions to positional astronomy and planetary dynamics. On the more practical side, he determined a remarkably accurate value for the velocity of light, one within 0.01% of the value accepted today. His work provided an experimental grounding for the special and general theories of relativity to be formulated by Einstein in the coming twentieth century.

  13. Are Supernovae Recorded in Indigenous Astronomical Traditions?

    CERN Document Server

    Hamacher, Duane W

    2014-01-01

    Novae and supernovae are rare astronomical events that would have had an influence on the sky-watching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral and material culture, and claims from around the world are discussed to determine if they meet these criteria. Australian Aboriginal traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Indigenous traditions, and an account of a nova in Aboriginal traditions has been confirmed, there are currently no confirmed accounts of supernovae in Indigenous oral or material traditions.

  14. VOStat: A Statistical Web Service for Astronomers

    CERN Document Server

    Chakraborty, Arnab; Babu, G Jogesh

    2013-01-01

    VOStat is a Web service providing interactive statistical analysis of astronomical tabular datasets. It is integrated into the suite of analysis and visualization tools associated with the international Virtual Observatory (VO) through the SAMP communication system. A user supplies VOStat with a dataset extracted from the VO, or otherwise acquired, and chooses among $\\sim 60$ statistical functions. These include data transformations, plots and summaries, density estimation, one- and two-sample hypothesis tests, global and local regressions, multivariate analysis and clustering, spatial analysis, directional statistics, survival analysis (for censored data like upper limits), and time series analysis. The statistical operations are performed using the public domain {\\bf R} statistical software environment, including a small fraction of its $>4000$ {\\bf CRAN} add-on packages. The purpose of VOStat is to facilitate a wider range of statistical analyses than are commonly used in astronomy, and to promote use of m...

  15. Using the Galileoscope in astronomical observations

    CERN Document Server

    Oliveira, V A

    2015-01-01

    This project aims to attract school students and teachers from the state education system from Ca\\c{c}apava do Sul - RS to Sciences and specially to Astronomy. We made astronomical observations using a Galileoscope choosing the Moon as a primary target. We also observed others objects that present high brightness in the night sky. The selection of targets, and their identification during the observations were carried out by a free software of planetary simulation, Stellarium. The results were in qualitative form and they show the great interest demonstrated by those participating in the project. Furthermore, this project helped to improve the understanding of the physical proprieties of the night sky objects (e.g. color). Finally, the project has showed that using a simple equipment and of relatively low cost it is possible to bring more people, specially the young students, to the Science World and to Astronomy.

  16. Multinational History of Strasbourg Astronomical Observatory

    CERN Document Server

    Heck, André

    2005-01-01

    Strasbourg Astronomical Observatory is quite an interesting place for historians: several changes of nationality between France and Germany, high-profile scientists having been based there, big projects born or installed in its walls, and so on. Most of the documents circulating on the history of the Observatory and on related matters have however been so far poorly referenced, if at all. This made necessary the compilation of a volume such as this one, offering fully-documented historical facts and references on the first decades of the Observatory history, authored by both French and German specialists. The experts contributing to this book have done their best to write in a way understandable to readers not necessarily hyperspecialized in astronomy nor in the details of European history. After an introductory chapter by the Editor, contributions by Wolfschmidt and by Duerbeck respectively deal extensively with the German periods and review people and instrumentation, while another paper by Duerbeck is more...

  17. An Astronomer's View of Climate Change

    Science.gov (United States)

    Morton, Donald C.

    2014-01-01

    There are several astronomical effects that could be important for understanding climate changes such as the ice ages, the Medieval Maximum, the Little Ice Age, the 20th century temperature rise and the small decrease during the past 15 years. These effects include variations in the sun's luminosity, periodic changes in the earth's orbital parameters, the sun's orbit around our galaxy, the solar wind, the variability of solar activity and the anticorrelation of the galactic cosmic ray flux with that activity. With the publication of the Fifth Assessment Report to the Intergoverment Panel on Climate Change, it is useful to review these effects and the extent to which that report and previoius ones have recognized them. This paper also discusses recent trends in solar activity and global temperatures and compares the latter with the predictions of climate models.

  18. Integral Programme of Basic Astronomic Literacy Development

    Science.gov (United States)

    Tignanelli, H.

    2009-05-01

    We discuss the development and optimization of an ongoing educational project involving the whole population of the province of San Luis, Argentina. The core of the project includes activities and resources that capture formal curricular aspects directed towards all levels of teaching. The educational activities related to this project have been benefited by the acquisition of two planetariums made in Argentina, a MEADE 16'' telescope to be operated by remote control from any school-room in San Luis, and a naked-eye observatory with more than 30 pre-telescopic instruments, and other didactic tools specially designed for the teaching of Astronomy. Furthermore, an Internet site to upload all the astronomical activities suggested that has been developed along with a number of didactic and general-interest publications.

  19. Astronomers Gain Clues About Fundamental Physics

    Science.gov (United States)

    2005-12-01

    An international team of astronomers has looked at something very big -- a distant galaxy -- to study the behavior of things very small -- atoms and molecules -- to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time. The Green Bank Telescope The Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF (Click on image for GBT gallery) "The fundamental constants of physics are expected to remain fixed across space and time; that's why they're called constants! Now, however, new theoretical models for the basic structure of matter indicate that they may change. We're testing these predictions." said Nissim Kanekar, an astronomer at the National Radio Astronomy Observatory (NRAO), in Socorro, New Mexico. So far, the scientists' measurements show no change in the constants. "We've put the most stringent limits yet on some changes in these constants, but that's not the end of the story," said Christopher Carilli, another NRAO astronomer. "This is the exciting frontier where astronomy meets particle physics," Carilli explained. The research can help answer fundamental questions about whether the basic components of matter are tiny particles or tiny vibrating strings, how many dimensions the Universe has, and the nature of "dark energy." The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant. These values, considered fundamental physical constants, once were "taken as time independent, with values given once and forever" said German particle physicist Christof Wetterich. However, Wetterich explained, "the viewpoint of modern particle theory has changed in recent years," with ideas such as

  20. Daytime School Guided Visits to an Astronomical Observatory in Brazil

    Science.gov (United States)

    Colombo, Pedro Donizete, Jr.; Silva, Cibelle Celestino; Aroca, Silvia Calbo

    2010-01-01

    This article analyzes the activity "Daytime School Guided Visits" at an astronomical observatory in Brazil with pupils from primary school. The adopted research methodology relied on questionnaire applications and semistructured interviews. The objectives were to identify the influences of the visits on learning of astronomical concepts and on…

  1. Using Modern Technologies to Capture and Share Indigenous Astronomical Knowledge

    OpenAIRE

    Nakata, N. M.; Hamacher, D. W.; Warren, J.; Byrne, A; Pagnucco, M.; Harley, R.; Venugopal, S.; Thorpe, K.; Neville, R.; Bolt, R.

    2014-01-01

    Indigenous Knowledge is important for Indigenous communities across the globe and for the advancement of our general scientific knowledge. In particular, Indigenous astronomical knowledge integrates many aspects of Indigenous Knowledge, including seasonal calendars, navigation, food economics, law, ceremony, and social structure. We aim to develop innovative ways of capturing, managing, and disseminating Indigenous astronomical knowledge for Indigenous communities and the general public for t...

  2. The lamps of Atlantis: an astronomical detective story

    Science.gov (United States)

    Roy, Archie E.

    1986-11-01

    The origin of the stellar constellations familiar to western astronomers from ancient times is discussed using astronomical, literary, and archaeological evidence. The precession of the equinoxes, the zone of avoidance and the orientation of the constellations, and early Greek and Minoan astronomy are considered.

  3. The challengers of an astronomer being a journalist

    Science.gov (United States)

    Podorvanyuk, N.

    2015-03-01

    As the weakness of russian astronomers in observational astronomy became chronic Russia should enter European Southern Observatory. But the Russian government is still not providing any financing of the entrance of Russia to ESO. The author states this situation as an example of his experience of work as an astronomer and as a journalist at the same time.

  4. Software Package for Preparing and Processing of an Astronomical Observation

    Science.gov (United States)

    Vaduvescu, Ovidiu; Birlan, Mirel

    This paper presents an astronomical software package which draws celestial charts. It was conceived taking into account the technical possibilities available for the Romanian astronomers and the actual trend of the observational astronomy. The software package, now to its third version, comes to decrease the time to prepare an observation and to perform accurate charts for searching and identification.

  5. Astronomical Books and Charts in the Book of Bibliographie Coreenne

    Science.gov (United States)

    Lee, Ki-Won; Yang, Hong-Jin; Park, Myeong-Gu

    2008-06-01

    We investigate astronomical materials listed in the book of Bibliographie Coréenne written by Maurice Courant. He classified ancient Korean books into nine Divisions (?) and thirty six Classes (?), and published them as three volumes (ranging from 1894 to 1896) and one supplement (in 1901). In total, 3,821 books including astronomical ones are listed together with information on physical size, possessional place, bibliographical note, and so forth. Although this book is an essential one in the field of Korea bibliography and contains many astronomical materials such as Cheon-Mun-Ryu-Cho ????, Si-Heon-Seo ??????, and Cheon-Sang-Yeol-Cha-Bun-Ya-Ji-Do ????????, it has not been well known to the public nor to astronomical society. Of 3,821 catalogues, we found that about 50 Items (?) are related to astronomy or astrology, and verified that most ! of them are located in the Kyujanggak Royal Library ???. We also found an unknown astronomical chart, Hon-Cheon-Chong-Seong-Yeol-Cha-Bun-Ya-Ji-Do ??????????. Because those astronomical materials are not well known to international astronomical community and there have been few studies on the materials in Korea, we here introduce and review them, particularly with the astronomical viewpoint.

  6. The Virtual Astronomical Observatory: Re-engineering Access to Astronomical Data

    CERN Document Server

    Hanisch, R J; Lazio, T J W; Bunn, S Emery; Evans, J; McGlynn, T A; Plante, R

    2015-01-01

    The U.S. Virtual Astronomical Observatory was a software infrastructure and development project designed both to begin the establishment of an operational Virtual Observatory (VO) and to provide the U.S. coordination with the international VO effort. The concept of the VO is to provide the means by which an astronomer is able to discover, access, and process data seamlessly, regardless of its physical location. This paper describes the origins of the VAO, including the predecessor efforts within the U.S. National Virtual Observatory, and summarizes its main accomplishments. These accomplishments include the development of both scripting toolkits that allow scientists to incorporate VO data directly into their reduction and analysis environments and high-level science applications for data discovery, integration, analysis, and catalog cross-comparison. Working with the international community, and based on the experience from the software development, the VAO was a major contributor to international standards ...

  7. Detection and removal of artifacts in astronomical images

    Science.gov (United States)

    Desai, S.; Mohr, J. J.; Bertin, E.; Kümmel, M.; Wetzstein, M.

    2016-07-01

    Astronomical images from optical photometric surveys are typically contaminated with transient artifacts such as cosmic rays, satellite trails and scattered light. We have developed and tested an algorithm that removes these artifacts using a deep, artifact free, static sky coadd image built up through the median combination of point spread function (PSF) homogenized, overlapping single epoch images. Transient artifacts are detected and masked in each single epoch image through comparison with an artifact free, PSF-matched simulated image that is constructed using the PSF-corrected, model fitting catalog from the artifact free coadd image together with the position variable PSF model of the single epoch image. This approach works well not only for cleaning single epoch images with worse seeing than the PSF homogenized coadd, but also the traditionally much more challenging problem of cleaning single epoch images with better seeing. In addition to masking transient artifacts, we have developed an interpolation approach that uses the local PSF and performs well in removing artifacts whose widths are smaller than the PSF full width at half maximum, including cosmic rays, the peaks of saturated stars and bleed trails. We have tested this algorithm on Dark Energy Survey Science Verification data and present performance metrics. More generally, our algorithm can be applied to any survey which images the same part of the sky multiple times.

  8. Astronomical Site Ranking Based on Tropospheric Wind Statistics

    CERN Document Server

    García-Lorenzo, B; Muñoz-Tunón, C; Mendizabal, E

    2004-01-01

    We present comprehensive and reliable statistics of high altitude wind speeds and the tropospheric flows at the location of five important astronomical observatories. Statistical analysis exclusively of high altitude winds point to La Palma as the most suitable site for adaptive optics, with a mean value of 22.13 m/s at the 200 mbar pressure level. La Silla is at the bottom of the ranking, with the largest average value 200 mbar wind speed(33.35 m/s). We have found a clear annual periodicity of high altitude winds for the five sites in study. We have also explored the connection of high to low altitude atmospheric winds as a first approach of the linear relationship between the average velocity of the turbulence and high altitude winds (Sarazin & Tokovinin 2001). We may conclude that high and low altitude winds show good linear relationships at the five selected sites. The highest correlation coefficients correspond to Paranal and San Pedro Martir, while La Palma and La Silla show similar high to low alti...

  9. Astronomical site selection for Turkey using GIS techniques

    Science.gov (United States)

    Aksaker, N.; Yerli, S. K.; Erdoğan, M. A.; Erdi, E.; Kaba, K.; Ak, T.; Aslan, Z.; Bakış, V.; Demircan, O.; Evren, S.; Keskin, V.; Küçük, İ.; Özdemir, T.; Özışık, T.; Selam, S. O.

    2015-10-01

    A site selection of potential observatory locations in Turkey have been carried out by using Multi-Criteria Decision Analysis (MCDA) coupled with Geographical Information Systems (GIS) and satellite imagery which in turn reduced cost and time and increased the accuracy of the final outcome. The layers of cloud cover, digital elevation model, artificial lights, precipitable water vapor, aerosol optical thickness and wind speed were studied in the GIS system. In conclusion of MCDA, the most suitable regions were found to be located in a strip crossing from southwest to northeast including also a diverted region in southeast of Turkey. These regions are thus our prime candidate locations for future on-site testing. In addition to this major outcome, this study has also been applied to locations of major observatories sites. Since no goal is set for the best, the results of this study is limited with a list of positions. Therefore, the list has to be further confirmed with on-site tests. A national funding has been awarded to produce a prototype of an on-site test unit (to measure both astronomical and meteorological parameters) which might be used in this list of locations.

  10. The Double Didactic Astronomical Quadrant for the XIII International Astronomical Olympiad

    OpenAIRE

    Maris, Michele; Corte, Claudio; Boehm, Conrad; Iafrate, Giulia; Ramella, Massimo

    2010-01-01

    Here we present the development of a simplified version of double astronomical quadrant, designed for educational aims and realized on the occasion of the observational round of the XIII International Astronomy Olympiad, held in Trieste (Italy) October 13-21, 2008. (Italia: In questo contributo illustriamo il progetto di una versione semplificata di doppio quadrante astronomico, progettato per fini didattici e realizzato in occasione dello svolgimento della gara osservativa delle XIII Olimpia...

  11. Performance Verification of the Gravity and Extreme Magnetism Small Explorer GEMS X-Ray Polarimeter

    Science.gov (United States)

    Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kanako, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Kenward, David

    2014-01-01

    olarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor greater than or equal to 35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, approximately 20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

  12. A Transmissive X-ray Polarimeter Design For Hard X-ray Focusing Telescopes

    CERN Document Server

    Li, Hong; Ji, Jianfeng; Deng, Zhi; He, Li; Zeng, Ming; Li, Tenglin; Liu, Yinong; Heng, Peiyin; Wu, Qiong; Han, Dong; Dong, Yongwei; Lu, Fangjun; Zhang, Shuangnan

    2015-01-01

    The X-ray Timing and Polarization (XTP) is a mission concept for a future space borne X-ray observatory and is currently selected for early phase study. We present a new design of X-ray polarimeter based on the time projection gas chamber. The polarimeter, placed above the focal plane, has an additional rear window that allows hard X-rays to penetrate (a transmission of nearly 80% at 6 keV) through it and reach the detector on the focal plane. Such a design is to compensate the low detection efficiency of gas detectors, at a low cost of sensitivity, and can maximize the science return of multilayer hard X-ray telescopes without the risk of moving focal plane instruments. The sensitivity in terms of minimum detectable polarization, based on current instrument configuration, is expected to be 3% for a 1mCrab source given an observing time of 10^5 s. We present preliminary test results, including photoelectron tracks and modulation curves, using a test chamber and polarized X-ray sources in the lab.

  13. Gas Gain Measurements from a Negative Ion TPC X-ray Polarimeter

    CERN Document Server

    Prieskorn, Z; Kaaret, P E; Black, J K; Jahoda, K

    2011-01-01

    Gas-based time projection chambers (TPCs) have been shown to be highly sensitive X-ray polarimeters having excellent quantum efficiency while at the same time achieving large modulation factors. To observe polarization of the prompt X-ray emission of a Gamma-ray burst (GRB), a large area detector is needed. Diffusion of the electron cloud in a standard TPC could be prohibitive to measuring good modulation when the drift distance is large. Therefore, we propose using a negative ion TPC (NITPC) with Nitromethane (CH3NO2) as the electron capture agent. The diffusion of negative ions is reduced over that of electrons due to the thermal coupling of the negative ions to the surrounding gas. This allows for larger area detectors as the drift distance can be increased without degrading polarimeter modulation. Negative ions also travel ~200 times slower than electrons, allowing the readout electronics to operate slower, resulting in a reduction of instrument power. To optimize the NITPC design, we have measured gas ga...

  14. Spin-Filter Polarimeter: On-line Proton and Deuteron Polarimetry in Real Time

    Science.gov (United States)

    Ropera, B.; Mendez, C.; Dunham, B.; Clegg, C.

    1996-05-01

    The Spin-Filter Polarimeter system (SFP)(A.J. Mendez, et al.), submitted to Rev. of Scientific Instruments monitors the nuclear polarization of the H^± or D^± ions produced by the Atomic Beam Polarized Ion Source (ABPIS) at Triangle Universities Nuclear Laboratory (TUNL). This system is based on the "spin-filter," a rf cavity designed for use in the Lamb-shift polarized ion source developed at Los Alamos National Laboratory(J.L. McKibben, et al.), Phys. Rev. Lett. 20, 1180 (1968). The SFP determines the polarization of the H^± or D^± ions by measuring the relative hyperfine state populations of the 2S_1/2 metastable H or D atoms produced as a by-product of the negative ionization process (H^+ + 2e^-arrow H^-) in the ABPIS. SFP polarization measurements taken concurrently with calibrated nuclear polarimeters resulted in absolute rms differences of 0.023 or less. Principle of operation, description of hardware, comparison measurements, and impressions gained from the use of the SFP as a real time tuning device and absolute polarization monitor will be discussed.

  15. On the operation of X-ray polarimeters with a large field of view

    CERN Document Server

    Muleri, Fabio

    2013-01-01

    The measurement of the linear polarization is one of the hot topics of High Energy Astrophysics. Gas detectors based on photoelectric effect have paved the way for the design of sensitive instruments and mission proposals based on them have been presented in the last few years in the energy range from about 2 keV to a few tens of keV. As well, a number of polarimeters based on Compton scattering are approved or discussed for launch on-board balloons or space satellites at higher energies. These instruments are typically dedicated to pointed observations with narrow field of view telescopes or collimators, but there are also projects aimed at the polarimetry of bright transient sources, like Soft Gamma Repeaters or the prompt emission of Gamma Ray Bursts. Given the erratic appearance of such events in the sky, these polarimeters have a large field of view to catch a reasonable number of them and, as a result, photons may impinge on the detector off-axis. This changes dramatically the response of the instrument...

  16. Microphysical Properties of Aerosols Encountered During the 2012 TCAP Campaign Using the Research Scanning Polarimeter

    Science.gov (United States)

    Stamnes, S.; Ferrare, R. A.; Hostetler, C. A.; Burton, S. P.; Liu, X.; Cairns, B.

    2015-12-01

    The Two-Column Aerosol Project (TCAP) campaign was conducted during the summer of 2012, off the East coast of the United States by Cape Cod. The NASA GISS Research Scanning Polarimeter, a multi-angle, multi-spectral polarimeter measured the upwelling polarized radiances from a B200 aircraft over a period of several weeks and over a distance of several hundred kilometers. A new algorithm based on optimal estimation that can retrieve aerosol microphysical properties using highly accurate radiative transfer and Mie calculations is presented. First, results for synthetic simulated data are discussed. The algorithm is then applied to real data collected during TCAP to retrieve the aerosol microphysical state vector and corresponding uncertainty for the aerosols that were encountered. Simultaneous measurements were also made by the NASA Langley airborne High Spectral Resolution Lidar (HSRL2), which provided extinction and backscatter profiles. The RSP-retrieved microphysical properties are compared to the extinction and backscatter products, and to the HSRL2-retrieved microphysical products.

  17. Optimization of the Design of the Hard X-ray Polarimeter X-Calibur

    CERN Document Server

    Guo, Qingzhen; Garson, Alfred; Kislat, Fabian; Fleming, David; Krawczynski, Henric; 10.1016/j.astropartphys.2012.11.006

    2012-01-01

    We report on the optimization of the hard X-ray polarimeter X-Calibur for a high-altitude balloon-flight in the focal plane of the InFOC{\\mu}S X-ray telescope from Fort Sumner (NM) in Fall 2013. X-Calibur combines a low-Z scintillator slab to Compton-scatter photons with a high-Z Cadmium Zinc Telluride (CZT) detector assembly to photo-absorb the scattered photons. The detector makes use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity and reaches a sensitivity close to the best theoretically possible. In this paper, we discuss the optimization of the design of the instrument based on Monte Carlo simulations of polarized and unpolarized X-ray beams and of the most important background components. We calculate the sensitivity of the polarimeter for the upcoming balloon flight from Fort Sumner and for additional longer balloon flights with higher throughput mirrors. We conclude by empha...

  18. A polarimeter for GeV protons of recirculating synchrotron beams

    CERN Document Server

    Bauer, F

    1999-01-01

    A polarimeter for use in recirculating beams of proton synchrotrons with energies from 300 MeV up to several GeV has been developed. The polarimetry is based on the asymmetry measurement of elastic p->p scattering on an internal CH sub 2 fiber target. The forward going protons are detected with two scintillator systems on either side of the beam pipe close to the angle THETA sub f of maximum analyzing power A sub N. Each one operates in coincidence with a broad (DELTA THETA sub b =21.4 deg. ), segmented detector system for the recoil proton of kinematically varying direction THETA sub b; this position resolution is also used for a concurrent measurement of the p->C and nonelastic p->p background. The CH sub 2 fiber can be replaced by a carbon fiber for detailed background studies; 'false' asymmetries are accounted for with a rotation of the polarimeter around the beam axis. Polarimetry has been performed in the internal beam of the Cooler Synchrotron COSY at fixed energies as well as during proton acceleratio...

  19. A high-contrast imaging polarimeter with a stepped-transmission filter based coronagraph

    Science.gov (United States)

    Liu, Cheng-Chao; Ren, De-Qing; Zhu, Yong-Tian; Dou, Jiang-Pei; Guo, Jing

    2016-05-01

    The light reflected from planets is polarized mainly due to Rayleigh scattering, but starlight is normally unpolarized. Thus it provides an approach to enhance the imaging contrast by inducing the imaging polarimetry technique. In this paper, we propose a high-contrast imaging polarimeter that is optimized for the direct imaging of exoplanets, combined with our recently developed stepped-transmission filter based coronagraph. Here we present the design and calibration method of the polarimetry system and the associated test of its high-contrast performance. In this polarimetry system, two liquid crystal variable retarders (LCVRs) act as a polarization modulator, which can extract the polarized signal. We show that our polarimeter can achieve a measurement accuracy of about 0.2% at a visible wavelength (632.8 nm) with linearly polarized light. Finally, the whole system demonstrates that a contrast of 10‑9 at 5λ/D is achievable, which can be used for direct imaging of Jupiter-like planets with a space telescope.

  20. Systematic and Performance Tests of the Hard X-ray Polarimeter X-Calibur

    Science.gov (United States)

    Endsley, Ryan; Beilicke, Matthias; Kislat, Fabian; Krawczynski, Henric; X-Calibur/InFOCuS

    2015-01-01

    X-ray polarimetry has great potential to reveal new astrophysical information about the emission processes of high energy sources such as black hole environments, X-ray binary systems, and active galactic nuclei. Here we present the results and conclusions of systematic and performance measurements of the hard X-ray polarimeter, X-Calibur. Designed to be flown on a balloon-borne X-ray telescope, X-Calibur will achieve unprecedented sensitivity and makes use of the fact that polarized X-rays preferentially Compton-scatter perpendicular to their E-field vector. Extensive laboratory measurements taken at Washington University and the Cornell High-Energy Synchrotron Source (CHESS) indicate that X-Calibur combines a detection efficiency on the order of unity with a high modulation factor of µ ≈ 0.5 averaged over the whole detector assembly, and with values up to µ ≈ 0.7 for select subsections of the polarimeter. Additionally, we are able to suppress background flux by more than two orders of magnitude by utilizing an active shield and scintillator coincidence. Comparing laboratory data with Monte Carlo simulations of both polarized and unpolarized hard X-ray beams illustrate that we have an exceptional understanding of the detector response.

  1. Astronomers Discover Fastest-Spinning Pulsar

    Science.gov (United States)

    2006-01-01

    Astronomers using the National Science Foundation's Robert C. Byrd Green Bank Telescope have discovered the fastest-spinning neutron star ever found, a 20-mile-diameter superdense pulsar whirling faster than the blades of a kitchen blender. Their work yields important new information about the nature of one of the most exotic forms of matter known in the Universe. Pulsar Graphic Pulsars Are Spinning Neutron Stars CREDIT: Bill Saxton, NRAO/AUI/NSF (Click on image for larger version) "We believe that the matter in neutron stars is denser than an atomic nucleus, but it is unclear by how much. Our observations of such a rapidly rotating star set a hard upper limit on its size, and hence on how dense the star can be.," said Jason Hessels, a graduate student at McGill University in Montreal. Hessels and his colleagues presented their findings to the American Astronomical Society's meeting in Washington, DC. Pulsars are spinning neutron stars that sling "lighthouse beams" of radio waves or light around as they spin. A neutron star is what is left after a massive star explodes at the end of its "normal" life. With no nuclear fuel left to produce energy to offset the stellar remnant's weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name "neutron star." "Neutron stars are incredible laboratories for learning about the physics of the fundamental particles of nature, and this pulsar has given us an important new limit," explained Scott Ransom, an astronomer at the National Radio Astronomy Observatory and one of Hessels' collaborators on this work. The scientists discovered the pulsar, named PSR J1748-2446ad, in a globular cluster of stars called Terzan 5, located some 28,000 light-years from Earth in the constellation Sagittarius. The newly-discovered pulsar is spinning 716 times per second, or at 716 Hertz (Hz), readily beating the previous record of 642 Hz from a pulsar

  2. NRAO Astronomer Wins Prestigious Guggenheim Fellowship

    Science.gov (United States)

    2010-04-01

    Dr. Dale Frail, an astronomer at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, has been awarded a prestigious Guggenheim Fellowship, according to the John Simon Guggenheim Memorial Foundation. The Guggenheim Foundation describes its fellowships as "mid-career" awards "intended for men and women who have already demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the arts." Frail, 48, has worked at the NRAO for more than 20 years, first as a postdoctoral fellow, and then as a staff scientist. He received his bachelor's degree in physics from Acadia University in Nova Scotia, and his Ph.D in astronomy from the University of Toronto. Frail is best known for his landmark contributions to the understanding of gamma ray bursts, making critical measurements that provided key insights into the mechanisms of these superenergetic and once-mysterious explosions. He also has made important contributions to the understanding of other astronomical phenomena, including pulsars and their neighborhoods, supernova remnants, and magnetars. In 1992, he was the co-discoverer, with Alex Wolszczan, of the first planets outside our own solar system. "We congratulate Dale on this well-deserved honor that recognizes not only his past achievements but also his potential for exciting scientific work in the future," said Dr. Fred K.Y. Lo, NRAO Director. "We're very proud to see one of our scientists receive such a great honor," Lo added. Frail is one of 180 recipients of this year's Guggenheim Fellowships, chosen from some 3,000 applicants. The fellowships were established in 1925 and past recipients include photographer Ansel Adams, author Saul Bellow, former Secretary of State Henry Kissinger, and chemist Linus Pauling. 102 Guggenheim Fellows have subsequently won Nobel Prizes, and others have received Pulitzer Prizes and other honors. As a Guggenheim Fellow, Frail intends to intensify his research in the areas of pulsars

  3. Optical Design and Active Optics Methods in Astronomy

    CERN Document Server

    Lemaitre, Gerard R

    2013-01-01

    Optical designs for astronomy involve implementation of active optics and adaptive optics from X-ray to the infrared. Developments and results of active optics methods for telescopes, spectrographs and coronagraph planet finders are presented. The high accuracy and remarkable smoothness of surfaces generated by active optics methods also allow elaborating new optical design types with high aspheric and/or non-axisymmetric surfaces. Depending on the goal and performance requested for a deformable optical surface analytical investigations are carried out with one of the various facets of elasticity theory: small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, weakly conical shell theory. The resulting thickness distribution and associated bending force boundaries can be refined further with finite element analysis. Keywords: active optics, optical design, elasticity theory, astronomical optics, diffractive optics, X-ray optics

  4. Optimization of graded multilayer designs for astronomical x-ray telescopes

    DEFF Research Database (Denmark)

    Mao, P.H.; Harrison, F.A.; Windt, D.L.;

    1999-01-01

    We developed a systematic method for optimizing the design of depth-graded multilayers for astronomical hard-x-ray and soft-gamma-ray telescopes based on the instrument's bandpass and the field of view. We apply these methods to the design of the conical-approximation Wolter I optics employed...... by the balloon-borne High Energy Focusing Telescope, using W/Si as the multilayer materials. In addition, we present optimized performance calculations of mirrors, using other material pairs that are capable of extending performance to photon energies above the W K-absorption edge (69.5 keV), including Pt/C, Ni...

  5. CLaSPS: A NEW METHODOLOGY FOR KNOWLEDGE EXTRACTION FROM COMPLEX ASTRONOMICAL DATA SETS

    Energy Technology Data Exchange (ETDEWEB)

    D' Abrusco, R.; Fabbiano, G.; Laurino, O. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Djorgovski, G.; Donalek, C.; Longo, G. [Department of Astronomy, California Institute of Technology, MC 249-17 1200 East California Blvd, Pasadena, CA 91125 (United States)

    2012-08-20

    In this paper, we present the Clustering-Labels-Score Patterns Spotter (CLaSPS), a new methodology for the determination of correlations among astronomical observables in complex data sets, based on the application of distinct unsupervised clustering techniques. The novelty in CLaSPS is the criterion used for the selection of the optimal clusterings, based on a quantitative measure of the degree of correlation between the cluster memberships and the distribution of a set of observables, the labels, not employed for the clustering. CLaSPS has been primarily developed as a tool to tackle the challenging complexity of the multi-wavelength complex and massive astronomical data sets produced by the federation of the data from modern automated astronomical facilities. In this paper, we discuss the applications of CLaSPS to two simple astronomical data sets, both composed of extragalactic sources with photometric observations at different wavelengths from large area surveys. The first data set, CSC+, is composed of optical quasars spectroscopically selected in the Sloan Digital Sky Survey data, observed in the x-rays by Chandra and with multi-wavelength observations in the near-infrared, optical, and ultraviolet spectral intervals. One of the results of the application of CLaSPS to the CSC+ is the re-identification of a well-known correlation between the {alpha}{sub OX} parameter and the near-ultraviolet color, in a subset of CSC+ sources with relatively small values of the near-ultraviolet colors. The other data set consists of a sample of blazars for which photometric observations in the optical, mid-, and near-infrared are available, complemented for a subset of the sources, by Fermi {gamma}-ray data. The main results of the application of CLaSPS to such data sets have been the discovery of a strong correlation between the multi-wavelength color distribution of blazars and their optical spectral classification in BL Lac objects and flat-spectrum radio quasars, and a

  6. Book Review: Scientific Writing for Young Astronomers

    Science.gov (United States)

    Uyttenhove, Jos

    2011-12-01

    EDP Sciences, Les Ulis, France. Part 1 : 162 pp. € 35 ISBN 978-2-7598-0506-8 Part 2 : 298 pp. € 60 ISBN 978-2-7598-0639-3 The journal Astronomy & Astrophysics (A&A) and EDP Sciences decided in 2007 to organize a School on the various aspects of scientific writing and publishing. In 2008 and 2009 Scientific Writing for Young Astronomers (SWYA) Schools were held in Blankenberge (B) under the direction of Christiaan Sterken (FWO-VUB). These two books (EAS publication series, Vol. 49 and 50) reflect the outcome of these Schools. Part 1 contains a set of contributions that discuss various aspects of scientific publication; it includes A&A Editors' view of the peer review and publishing process. A very interesting short paper by S.R. Pottasch (Kapteyn Astronomical Institute, Groningen, and one of the two first Editors-in Chief of A&A) deals with the history of the creation of the journal Astronomy & Astrophysics. Two papers by J. Adams et al. (Observatoire de Paris) discuss language editing, including a detailed guide for any non-native user of the English language. In 2002 the Board of Directors decided that all articles in A&A must be written in clear and correct English. Part 2 consists of three very extensive and elaborated papers by Christiaan Sterken, supplying guidelines to PhD students and postdoctoral fellows to help them compose scientific papers for different forums (journals, proceedings, thesis, etc.). This part is of interest not only for young astronomers but it is very useful for scholars of all ages and disciplines. Paper I "The writing process" (60 pp.) copes with the preparation of manuscripts, with communicating with editors and referees and with avoiding common errors. Delicate problems on authorship, refereeing, revising multi-authored papers etc. are treated in 26 FAQ's. Paper II "Communication by graphics" (120 pp.) is entirely dedicated to the important topic of communication with images, graphs, diagrams, tables etc. Design types of graphs

  7. Model based systems engineering for astronomical projects

    Science.gov (United States)

    Karban, R.; Andolfato, L.; Bristow, P.; Chiozzi, G.; Esselborn, M.; Schilling, M.; Schmid, C.; Sommer, H.; Zamparelli, M.

    2014-08-01

    Model Based Systems Engineering (MBSE) is an emerging field of systems engineering for which the System Modeling Language (SysML) is a key enabler for descriptive, prescriptive and predictive models. This paper surveys some of the capabilities, expectations and peculiarities of tools-assisted MBSE experienced in real-life astronomical projects. The examples range in depth and scope across a wide spectrum of applications (for example documentation, requirements, analysis, trade studies) and purposes (addressing a particular development need, or accompanying a project throughout many - if not all - its lifecycle phases, fostering reuse and minimizing ambiguity). From the beginnings of the Active Phasing Experiment, through VLT instrumentation, VLTI infrastructure, Telescope Control System for the E-ELT, until Wavefront Control for the E-ELT, we show how stepwise refinements of tools, processes and methods have provided tangible benefits to customary system engineering activities like requirement flow-down, design trade studies, interfaces definition, and validation, by means of a variety of approaches (like Model Checking, Simulation, Model Transformation) and methodologies (like OOSEM, State Analysis)

  8. Astronomical Forcing of Salt Marsh Biogeochemical Cascades

    Science.gov (United States)

    Morris, J. T.; Sundberg, K.

    2008-12-01

    Astronomically forced changes in the hydroperiod of a salt marsh affect the rate of marsh primary production leading to a biogeochemical cascade. For example, salt marsh primary production and biogeochemical cycles in coastal salt marshes are sensitive to the 18.6-year lunar nodal cycle, which alters the tidal amplitude by about 5 cm. For marshes that are perched high in the tidal frame, a relatively small increase in tidal amplitude and flooding lowers sediment salinity and stimulates primary production. Porewater sulfide concentrations are positively correlated with tidal amplitude and vary on the same cycle as primary production. Soluble reactive phosphate and ammonium concentrations in pore water also vary on this 18.6- year cycle. Phosphate likely responds to variation in the reaction of sulfide with iron-phosphate compounds, while the production of ammonium in sediments is coupled to the activity of diazotrophs that are carbon- limited and, therefore, are regulated by primary productivity. Ammonium also would accumulate when sulfides block nitrification. These dependencies work as a positive feedback between primary production and nutrient supply and are predictive of the near-term effects of sea-level rise.

  9. Is astronomical research appropriate for developing countries?

    Science.gov (United States)

    Snowden, Michael S.

    An unproductive 45-cm astronomical telescope, given by JICA (Japan) to Sri Lanka, raises general questions as to the reasons for unproductive pure science in developing countries. Before installation, site, maintenance, and scientific objectives were discussed. The facility was launched with a conference organised by the UN Office for Outer Space Affairs. Unfortunately, no research or significant education has resulted after four years. The annual operating cost is U.S. $5000 per year, including salary for a trainee, maintenance, and a modest promotional programme. Comparison with a similar installation in Auckland suggests lack of funding or technical competence do not explain the failure in Sri Lanka. The facility in New Zealand, on the roof of Auckland University's Physics Department, has a slightly smaller budget but has led to modest but useful research and teaching. Lack of financial backing and expertise are often blamed for weak science in developing countries, but examination shows most of these countries have adequately skilled people, and plenty of resources for religion and military. General lack of motivation for science appears to be the principal reason. This lack of interest and highly inefficient bureaucracies are common to scientifically unproductive countries. They mostly lack the cultural and philosophical base of the European Renaissance that motivate the pursuit of modern science, an activity that violates human preferences. There are excellent facilities (ESO, SAAO, Cerro Tololo, and GONG) in some of these same countries, when administered from the West.

  10. Compact Stirling cooling of astronomical detectors

    CERN Document Server

    Raskin, Gert; Pessemier, Wim; Padilla, Jesus Perez; Vandersteen, Jeroen

    2013-01-01

    MAIA, a three-channel imager targeting fast cadence photometry, was recently installed on the Mercator telescope (La Palma, Spain). This instrument observes a 9.4 x 14.1 arcmin field of view simultaneously in three color bands ($u$, $g$ and $r$), using three of the largest (un-) available frame-transfer CCDs, namely the 2k x 6k CCD42-C0 from e2v. As these detectors are housed in three separate cryostats, compact cooling devices are required that offer sufficient power to cool the large chips to a temperature of 165K. We explored a broad spectrum of cooling options and technologies to cool the MAIA detectors. Finally, compact free-piston Stirling coolers were selected, namely the CryoTel MT cryo-coolers from SUNPOWER, that can extract 5W of heat at a temperature of 77K. In this contribution we give details of the MAIA detector cooling solution. We also discuss the general usability of this type of closed-cycle cryo-coolers for astronomical detectors. They offer distinct advantages but the vibrations caused by ...

  11. The Taiwan Extragalactic Astronomical Data Center

    CERN Document Server

    Foucaud, Sébastien; Tsai, Meng-Feng; Kamennoff, Nicolas

    2012-01-01

    Founded in 2010, the Taiwan Extragalactic Astronomical Data Center (TWEA-DC) has for goal to propose access to large amount of data for the Taiwanese and International community, focusing its efforts on Extragalactic science. In continuation with individual efforts in Taiwan over the past few years, this is the first steppingstone towards the building of a National Virtual Observatory. Taking advantage of our own fast indexing algorithm (BLINK), based on a octahedral meshing of the sky coupled with a very fast kd-tree and a clever parallelization amongst available resources, TWEA-DC will propose from spring 2013 a service of "on-the-fly" matching facility, between on-site and user-based catalogs. We will also offer access to public and private raw and reducible data available to the Taiwanese community. Finally, we are developing high-end on-line analysis tools, such as an automated photometric redshifts and SED fitting code (APz), and an automated groups and clusters finder (APFoF).

  12. The Research Use of Astronomical Monographs

    Science.gov (United States)

    Abt, Helmut A.

    2014-04-01

    I explored the use of astronomical monographs used for research. After scanning 135 monographs (excluding conference proceedings and textbooks) listed in 2000-2003 issues of Physics Today and counting citations of them in 2000-2013 in ADS (Astrophysics Data System), I found that 67% of the monographs received fewer than 2 citations per year. The average citation rate for the 135 monographs is statistically the same as for ApJ papers. In contrast, only 41% of the ApJ papers produce fewer than 2 citations per year. ADS also counts the number of times each book or paper is read on-line. The average in 14 years is 181 ± 27 times for the monographs and 633 ± 47 times for ApJ papers. The total numbers of citations in 14 years for the monographs ranged from 0 to 711. I explored reasons for this range and only learned that it did not depend on (1) the numbers of book reviews published or (2) the scientific stature of the authors. I am unable to predict whether a monograph will be successful or not. The decreasing of references to monographs seems to be due to (1) monographs becoming so expensive that individuals and libraries cannot afford many of them, (2) readers seeming to prefer concise reviews, such as online searches and the Annual Reviews, and (3) most of the monographs having not been available free online.

  13. First Visiting Astronomers at VLT KUEYEN

    Science.gov (United States)

    2000-04-01

    A Deep Look into the Universal Hall of Mirrors Starting in the evening of April 1, 2000, Ghislain Golse and Francisco Castander from the Observatoire Midi-Pyrénées (Toulouse, France) [1] were the first "visiting astronomers" at Paranal to carry out science observations with the second 8.2-m VLT Unit Telescope, KUEYEN . Using the FORS2 multi-mode instrument as a spectrograph, they measured the distances to a number of very remote galaxies, located far out in space behind two clusters of galaxies. Such observations may help to determine the values of cosmological parameters that define the geometry and fate of the Universe. After two nights of observations, the astronomers came away from Paranal with a rich harvest of data and a good feeling. "We are delighted that the telescope performed so well. It is really impressive how far out one can reach with the VLT, compared to the `smaller' 4-meter telescopes with which we previously observed. It opens a new window towards the distant, early Universe. Now we are eager to start reducing and analysing these data!" , Francisco Castander said. Measuring the Geometry of the Universe with Multiple Images in Cluster Lenses The present programme is typical of the fundamental cosmological studies that are now being undertaken with the ESO Very Large Telescope (VLT). Clusters of galaxies are very massive objects. Their gravitational fields intensify ("magnify") and distort the images of galaxies behind them. The magnification factor for the faint background galaxy population seen within a few arcminutes of the centre of a massive cluster at intermediate distance (redshift z ~ 0.2 - 0.4, i.e., corresponding to a look-back time of approx. 2 - 4 billion years) is typically larger than 2, and occasionally much larger. The clusters thus function as gravitational lenses . They may be regarded as "natural telescopes" that help us to see fainter objects further out into space than would otherwise be possible with our own telescopes. In a

  14. The Virtual Astronomical Observatory: Re-engineering access to astronomical data

    Science.gov (United States)

    Hanisch, R. J.; Berriman, G. B.; Lazio, T. J. W.; Emery Bunn, S.; Evans, J.; McGlynn, T. A.; Plante, R.

    2015-06-01

    The US Virtual Astronomical Observatory was a software infrastructure and development project designed both to begin the establishment of an operational Virtual Observatory (VO) and to provide the US coordination with the international VO effort. The concept of the VO is to provide the means by which an astronomer is able to discover, access, and process data seamlessly, regardless of its physical location. This paper describes the origins of the VAO, including the predecessor efforts within the US National Virtual Observatory, and summarizes its main accomplishments. These accomplishments include the development of both scripting toolkits that allow scientists to incorporate VO data directly into their reduction and analysis environments and high-level science applications for data discovery, integration, analysis, and catalog cross-comparison. Working with the international community, and based on the experience from the software development, the VAO was a major contributor to international standards within the International Virtual Observatory Alliance. The VAO also demonstrated how an operational virtual observatory could be deployed, providing a robust operational environment in which VO services worldwide were routinely checked for aliveness and compliance with international standards. Finally, the VAO engaged in community outreach, developing a comprehensive web site with on-line tutorials, announcements, links to both US and internationally developed tools and services, and exhibits and hands-on training at annual meetings of the American Astronomical Society and through summer schools and community days. All digital products of the VAO Project, including software, documentation, and tutorials, are stored in a repository for community access. The enduring legacy of the VAO is an increasing expectation that new telescopes and facilities incorporate VO capabilities during the design of their data management systems.

  15. The Double Didactic Astronomical Quadrant for the XIII International Astronomical Olympiad

    CERN Document Server

    Maris, Michele; Boehm, Conrad; Iafrate, Giulia; Ramella, Massimo

    2010-01-01

    Here we present the development of a simplified version of double astronomical quadrant, designed for educational aims and realized on the occasion of the observational round of the XIII International Astronomy Olympiad, held in Trieste (Italy) October 13-21, 2008. (Italia: In questo contributo illustriamo il progetto di una versione semplificata di doppio quadrante astronomico, progettato per fini didattici e realizzato in occasione dello svolgimento della gara osservativa delle XIII Olimpiadi Internazionali di Astronomia (XIII International Astronomy Olympiad, XIII IAO), Trieste (I), 13-21 ottobre 2008))

  16. Relying on electronic journals: Reading patterns of astronomers

    Science.gov (United States)

    Tenopir, Carol; King, Donald W.; Boyce, Peter; Grayson, Matt; Paulson, Keri-Lynn

    2005-06-01

    Surveys of the members of the American Astronomical Society identify how astronomers use journals and what features and formats they prefer. While every work field is distinct, the patterns of use by astronomers may provide a glimpse of what to expect of journal patterns and use by other scientists. Astronomers, like other scientists, continue to invest a large amount of their time in reading articles and place a high level of importance on journal articles. They use a wide variety of formats and means to get access to materials that are essential to their work in teaching, service, and research. They select access means that are convenient - whether those means be print, electronic, or both. The availability of a mature electronic journals system from their primary professional society has surely influenced their early adoption of e-journals.

  17. The Persian-Toledan Astronomical Connection and the European Renaissance

    CERN Document Server

    Heydari-Malayeri, M

    2007-01-01

    This paper aims at presenting a brief overview of astronomical exchanges between the Eastern and Western parts of the Islamic world from the 8th to 14th century. These cultural interactions were in fact vaster involving Persian, Indian, Greek, and Chinese traditions. I will particularly focus on some interesting relations between the Persian astronomical heritage and the Andalusian (Spanish) achievements in that period. After a brief introduction dealing mainly with a couple of terminological remarks, I will present a glimpse of the historical context in which Muslim science developed. In Section 3, the origins of Muslim astronomy will be briefly examined. Section 4 will be concerned with Khwarizmi, the Persian astronomer/mathematician who wrote the first major astronomical work in the Muslim world. His influence on later Andalusian astronomy will be looked into in Section 5. Andalusian astronomy flourished in the 11th century, as will be studied in Section 6. Among its major achievements were the Toledan Tab...

  18. A Multilingual on-line Dictionary of Astronomical Concepts

    CERN Document Server

    Heydari-Malayeri, M

    2009-01-01

    On the occasion of the International Year of Astronomy (IYA2009), we present a new interactive dictionary of astronomy and astrophysics, which contains about 7000 entries. This interdisciplinary and multicultural work is intended for professional and amateur astronomers, university students in astrophysics, as well as terminologists and linguists. A new approach is pursued in the formation of a scientific dictionary, which aims to display additional dimensions of astronomical concepts. Although Virtual Observatories recognize the necessity of efforts to define basic astronomical concepts and establish their reciprocal relations, so far they have mainly been confined to archiving observational data. The present dictionary could be an incipient contribution to cover and inter-relate the whole astronomical lexicon beyond subfields.

  19. Lessons from the masters current concepts in astronomical image processing

    CERN Document Server

    2013-01-01

    There are currently thousands of amateur astronomers around the world engaged in astrophotography at increasingly sophisticated levels. Their ranks far outnumber professional astronomers doing the same and their contributions both technically and artistically are the dominant drivers of progress in the field today. This book is a unique collaboration of individuals, all world-renowned in their particular area, and covers in detail each of the major sub-disciplines of astrophotography. This approach offers the reader the greatest opportunity to learn the most current information and the latest techniques directly from the foremost innovators in the field today.   The book as a whole covers all types of astronomical image processing, including processing of eclipses and solar phenomena, extracting detail from deep-sky, planetary, and widefield images, and offers solutions to some of the most challenging and vexing problems in astronomical image processing. Recognized chapter authors include deep sky experts su...

  20. The Educational Activities of the Astronomical Society of the Pacific.

    Science.gov (United States)

    Fraknoi, Andrew

    1981-01-01

    Describes educational activities of the Astronomical Society of the Pacific including learning packets on various astronomy concepts, Morrison lectures, newspaper columns, teacher workshops, cosponsoring astronomy oriented lectures, and providing speakers for various groups. (DS)

  1. PPARC: Grid technology helps astronomers keep pace with the Universe

    CERN Multimedia

    2003-01-01

    "Intelligent Agent" computer programs are roaming the Internet and watching the skies. These programs, using Grid computing technology, will help astronomers detect some of the most dramatic events in the universe, such as massive supernova explosions (1 page).

  2. Astronomical Software Wants To Be Free: A Manifesto

    CERN Document Server

    Weiner, Benjamin J; Coil, Alison L; Cooper, Michael C; Davé, Romeel; Hogg, David W; Holden, Bradford P; Jonsson, Patrik; Kassin, Susan A; Lotz, Jennifer M; Moustakas, John; Newman, Jeffrey A; Prochaska, J X; Teuben, Peter J; Tremonti, Christy A; Willmer, Christopher N A

    2009-01-01

    Astronomical software is now a fact of daily life for all hands-on members of our community. Purpose-built software for data reduction and modeling tasks becomes ever more critical as we handle larger amounts of data and simulations. However, the writing of astronomical software is unglamorous, the rewards are not always clear, and there are structural disincentives to releasing software publicly and to embedding it in the scientific literature, which can lead to significant duplication of effort and an incomplete scientific record. We identify some of these structural disincentives and suggest a variety of approaches to address them, with the goals of raising the quality of astronomical software, improving the lot of scientist-authors, and providing benefits to the entire community, analogous to the benefits provided by open access to large survey and simulation datasets. Our aim is to open a conversation on how to move forward. We advocate that: (1) the astronomical community consider software as an integra...

  3. Expected performance of a hard X-ray polarimeter (POLAR) by Monte Carlo Simulation

    CERN Document Server

    Xiong, Shaolin; Wu, Bobing

    2009-01-01

    Polarization measurements of the prompt emission in Gamma-ray Bursts (GRBs) can provide diagnostic information for understanding the nature of the central engine. POLAR is a compact polarimeter dedicated to the polarization measurement of GRBs between 50-300 keV and is scheduled to be launched aboard the Chinese Space Laboratory about year 2012. A preliminary Monte Carlo simulation has been accomplished to attain the expected performance of POLAR, while a prototype of POLAR is being constructed at the Institute of High Energy Physics, Chinese Academy of Sciences. The modulation factor, efficiency and effective area, background rates and Minimum Detectable Polarization (MDP) were calculated for different detector configurations and trigger strategies. With the optimized detector configuration and trigger strategy and the constraint of total weight less than 30 kg, the primary science goal to determine whether most GRBs are strongly polarized can be achieved, and about 9 GRBs/yr can be detected with MDP < 10...

  4. Advanced ACTPol Multichroic Polarimeter Array Fabrication Process for 150 mm Wafers

    Science.gov (United States)

    Duff, S. M.; Austermann, J.; Beall, J. A.; Becker, D.; Datta, R.; Gallardo, P. A.; Henderson, S. W.; Hilton, G. C.; Ho, S. P.; Hubmayr, J.; Koopman, B. J.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Pappas, C. G.; Salatino, M.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Van Lanen, J.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-08-01

    Advanced ACTPol (AdvACT) is a third-generation cosmic microwave background receiver to be deployed in 2016 on the Atacama Cosmology Telescope (ACT). Spanning five frequency bands from 25 to 280 GHz and having just over 5600 transition-edge sensor (TES) bolometers, this receiver will exhibit increased sensitivity and mapping speed compared to previously fielded ACT instruments. This paper presents the fabrication processes developed by NIST to scale to large arrays of feedhorn-coupled multichroic AlMn-based TES polarimeters on 150-mm diameter wafers. In addition to describing the streamlined fabrication process which enables high yields of densely packed detectors across larger wafers, we report the details of process improvements for sensor (AlMn) and insulator (SiN_x) materials and microwave structures, and the resulting performance improvements.

  5. Far-forward collective scattering measurements by FIR polarimeter-interferometer on J-TEXT tokamak

    Science.gov (United States)

    Shi, P.; Chen, J.; Gao, L.; Liu, Y.; Liu, H.; Zhou, Y. N.; Zhuang, G.

    2016-11-01

    The multi-channel three-wave polarimeter-interferometer system on J-TEXT tokamak has been exploited to measure far-forward collective scattering from electron density fluctuations. The diagnostic utilizes far infrared lasers operated at 432 μm with 17-channel vertical chords (3 cm chord spacing), covering the entire cross section of plasma. Scattering laser power is measured using a high-sensitivity Schottky planar diode mixer which can also detect polarimetric and interferometric phase simultaneously. The system provides a line-integrated measurement of density fluctuations with maximum measurable wave number: k⊥max ≤ 2 cm-1 and time response up to 350 kHz. Feasibility of the diagnostic has been tested, showing higher sensitivity to detect fluctuation than interferometric measurement. Capability of providing spatial-resolved information of fluctuation has also been demonstrated in preliminary experimental applications.

  6. Preliminary design of the Visible Spectro-Polarimeter for the Advanced Technology Solar Telescope

    CERN Document Server

    de Wijn, Alfred G; Nelson, Peter G; Huang, Pei

    2012-01-01

    The Visible Spectro-Polarimeter (ViSP) is one of the first light instruments for the Advanced Technology Solar Telescope (ATST). It is an echelle spectrograph designed to measure three different regions of the solar spectrum in three separate focal planes simultaneously between 380 and 900 nm. It will use the polarimetric capabilities of the ATST to measure the full Stokes parameters across the line profiles. By measuring the polarization in magnetically sensitive spectral lines the magnetic field vector as a function of height in the solar atmosphere can be obtained, along with the associated variation of the thermodynamic properties. The ViSP will have a spatial resolution of 0.04 arcsec over a 2 arcmin field of view (at 600 nm). The minimum spectral resolving power for all the focal planes is 180,000. The spectrograph supports up to 4 diffraction gratings and is fully automated to allow for rapid reconfiguration.

  7. Derivation of Cumulus Cloud Dimensions and Shape from the Airborne Measurements by the Research Scanning Polarimeter

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; Ottaviani, Matteo; Wasilewski, Andrzej P.

    2016-01-01

    The Research Scanning Polarimeter (RSP) is an airborne instrument, whose measurements have been extensively used for retrievals of microphysical properties of clouds. In this study we show that for cumulus clouds the information content of the RSP data can be extended by adding the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground. This extension is possible by virtue of the high angular resolution and high frequency of the RSP measurements, which allow for geometric constraint of the cloud's 2D cross section between a number of tangent lines of view. The retrieval method is tested on realistic 3D radiative transfer simulations and applied to actual RSP data.

  8. Tokamak Plasmas : Internal magnetic field measurement in tokamak plasmas using a Zeeman polarimeter

    Indian Academy of Sciences (India)

    M Jagadeeshwari; J Govindarajan

    2000-11-01

    In a tokamak plasma, the poloidal magnetic field profile closely depends on the current density profile. We can deduce the internal magnetic field from the analysis of circular polarization of the spectral lines emitted by the plasma. The theory of the measurement and a detailed design of the Zeeman polarimeter constructed to measure the poloidal field profile in the ADITYA tokamak are presented. The Fabry-Perot which we have employed in our design, with photodiode arrays followed by lock-in detection of the polarization signal, allows the measurement of the fractional circular polarization. In this system He-II line with wavelength 4686 Å is adopted as the monitoring spectral line. The line emission used in the present measurement is not well localized in the plasma, necessiating the use of a spatial inversion procedure to obtain the local values of the field.

  9. In-line phase retarder and polarimeter for conversion of linear to circular polarization

    Energy Technology Data Exchange (ETDEWEB)

    Kortright, J.B.; Smith, N.V.; Denlinger, J.D. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    An in-line polarimeter including phase retarder and linear polarizer was designed and commissioned on undulator beamline 7.0 for the purpose of converting linear to circular polarization for experiments downstream. In commissioning studies, Mo/Si multilayers at 95 eV were used both as the upstream, freestanding phase retarder and the downstream linear polarized. The polarization properties of the phase retarder were characterized by direct polarimetry and by collecting MCD spectra in photoemission from Gd and other magnetic surfaces. The resonant birefringence of transmission multilayers results from differing distributions of s- and p-component wave fields in the multilayer when operating near a structural (Bragg) interference condition. The resulting phase retardation is especially strong when the interference is at or near the Brewster angle, which is roughly 45{degrees} in the EUV and soft x-ray ranges.

  10. Design and Tests of the Hard X-Ray Polarimeter X-Calibur

    Science.gov (United States)

    Beilicke, M.; Baring, M. G.; Barthelmy, S.; Binns, W. R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q.; Haba, Y.; Israel, M. H.; Kunieda, H.; Lee, K.; Matsumoto, H.; Miyazawa, T.; Okajima, T.; Schnittman, J.; Tamura, K.; Tueller, J.; Krawczynski, H.

    2012-01-01

    X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC(mu)S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10 - 80 keY X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

  11. Young Astronomers' Observe with ESO Telescopes

    Science.gov (United States)

    1995-11-01

    Today, forty 16-18 year old students and their teachers are concluding a one-week, educational `working visit' to the ESO Headquarters in Garching (See ESO Press Release 14/95 of 8 November 1995). They are the winners of the Europe-wide contest `Europe Towards the Stars', organised by ESO with the support of the European Union, under the auspices of the Third European Week for Scientific and Technological Culture. From November 14-20, they have worked with professional ESO astronomers in order to get insight into the methods and principles of modern astronomy and astrophysics, as carried out at one of the world's foremost international centres. This included very successful remote observations with the ESO 3.5-m New Technology Telescope (NTT) and the 1.4-m Coude Auxiliary Telescope (CAT) via a satellite link between the ESO Headquarters and the La Silla observatory in Chile, 12,000 kilometres away. After a general introduction to modern astronomy on the first day of the visit, the participants divided into six teams, according to their interests. Some chose to observe distant galaxies, others prefered to have a closer look on binary stars, and one team decided to investigate a star which is thought to be surrounded by a proto-planetary system. Each team was supported by an experienced ESO astronomer. Then followed the observations at the remote consoles during three nights, the first at the NTT and the following at the CAT. Each team had access to the telescope during half a night. Although the work schedule - exactly as in `real' science - was quite hard, especially during the following data reduction and interpretative phase, all teams managed extremely well and in high spirits. The young astronomers' observations were favoured by excellent atmospheric conditions. At the NTT, the seeing was better than 0.5 arcsecond during several hours, an exceptional value that allows very good images to be obtained. All observations represent solid and interesting science, and

  12. Some early astronomical sites in the Kashmir region

    Science.gov (United States)

    Iqbal, Naseer; Vahia, M. N.; Masood, Tabasum; Ahmad, Aijaz

    2009-03-01

    We discuss a number of early rock art sites in the Kashmir Valley in northern India and neighbouring Pakistan, and suggest that some of these contain depictions of astronomical objects or events. The sites are in the Srinagar and Sopore regions and in or near the Ladakh region, and date to Neolithic or Upper Paleolithic times. Our studies suggest that during this period some of the ancient astronomers recorded supernovae, meteorite impacts, the Sun, the Moon and the seasons in their rock art.

  13. Real-time earthquake warning for astronomical observatories

    CERN Document Server

    Coughlin, Michael; Barrientos, Sergio; Claver, Chuck; Harms, Jan; Smith, Christopher; Warner, Michael

    2014-01-01

    Early earthquake warning is a rapidly developing capability that has significant ramifications for many fields, including astronomical observatories. In this work, we describe the susceptibility of astronomical facilities to seismic events, including large telescopes as well as second-generation ground-based gravitational-wave interferometers. We describe the potential warning times for observatories from current seismic networks and propose locations for future seismometers to maximize warning times.

  14. A Survey for Transient Astronomical Radio Emission at 611 MHz

    OpenAIRE

    Katz, C. A.; Hewitt, J. N.; Corey, B. E.; Moore, C. B.

    2003-01-01

    We have constructed and operated the Survey for Transient Astronomical Radio Emission (STARE) to detect transient astronomical radio emission at 611 MHz originating from the sky over the northeastern United States. The system is sensitive to transient events on timescales of 0.125 s to a few minutes, with a typical zenith flux density detection threshold of approximately 27 kJy. During 18 months of around-the-clock observing with three geographically separated instruments, we detected a total...

  15. Blowing bubbles in the cosmos astronomical winds, jets, and explosions

    CERN Document Server

    Hartquist, T W; Ruffle, D P

    2004-01-01

    1. The First Discoveries of Astronomical Winds2. The Magnitudes of Astronomical Quantities3. Stellar Evolution4. Basic Structures of Winds and Windblown Bubbles5. Star Formation and Low-Mass Young Stellar Objects6. Regions of High-Mass Star Formation7. Winds from Main-Sequence and Post-Main-Sequence Stars8. Supernovae and Their Remnants9. Galactic Winds, Starburst Superwinds, and the Epoch of Galaxy Formation10. Active Galaxies and Their Nuclei11. Some Other Windy and Explosive Sources

  16. ASTRONOMICAL ALGORITHMS OF EGYPTIAN PYRAMIDS SLOPES AND THEIR MODULES DIVIDER

    OpenAIRE

    Aboulfotouh, Hossam M. K.

    2015-01-01

    This paper is an attempt to show the astronomical design principles that are encoded in the geometrical forms of the largest five pyramids of the fourth Egyptian dynasty, in Giza and Dahshur plateaus, based on using the pyramids’ design-modules that are mentioned in the so-called Rhind Mathematical Papyrus. It shows the astronomical algorithms for quantifying the slopes of pyramids, with reference to specific range of earth’s axial tilt, within spherical co-ordinates system. Besid...

  17. New developments at the NASA Astronomical Data Center

    Science.gov (United States)

    Warren, W. H., Jr.

    1985-01-01

    The need for a compilation catalog containing a large variety of astronomical data for the Astronomical Data Base of NASA is considered. It is suggested that the catalog should be prepared directly from the SIMBAD data base by processing through a single software program and made available for distribution on magnetic tape or microfilm. Annual updating is recommended to ensure the quality of the catalog. Data recommended for inclusion in the compilation catalog are listed in a table.

  18. Testing Quantum Mechanics and Bell's Inequality with Astronomical Observations

    Science.gov (United States)

    Friedman, Andrew S.; Kaiser, David I.; Gallicchio, Jason; Team 1: University of Vienna, InstituteQuantum Optics and Quantum Information; Team 2: UC San Diego Cosmology Group; Team 3: NASA/JPL/Caltech

    2016-06-01

    We report on an in progress "Cosmic Bell" experiment that will leverage cosmology to test quantum mechanics and Bell's inequality using astronomical observations. Different iterations of our experiment will send polarization-entangled photons through the open air to detectors ~1-100 kilometers apart, whose settings would be rapidly chosen using real-time telescopic observations of Milky Way stars, and eventually distant, causally disconnected, cosmological sources - such as pairs of quasars or patches of the cosmic microwave background - all while the entangled pair is still in flight. This would, for the first time, attempt to fully close the so-called "setting independence" or "free will" loophole in experimental tests of Bell's inequality, whereby an alternative theory could mimic the quantum predictions if the experimental settings choices shared even a small correlation with unknown, local, causal influences a mere few milliseconds prior to the experiment. A full Cosmic Bell test would push any such influence all the way back to the hot big bang, since the end of any period of inflation, 13.8 billion years ago, an improvement of 20 orders of magnitude compared to the best previous experiments. Redshift z > 3.65 quasars observed at optical wavelengths are the optimal candidate source pairs using present technology. Our experiment is partially funded by the NSF INSPIRE program, in collaboration with MIT, UC San Diego, Harvey Mudd College, NASA/JPL/Caltech, and the University of Vienna. Such an experiment has implications for our understanding of nature at the deepest level. By testing quantum mechanics in a regime never before explored, we would at the very least extend our confidence in quantum theory, while at the same time severely constraining large classes of alternative theories. If the experiment were to uncover discrepancies from the quantum predictions, there could be crucial implications for early-universe cosmology, the security of quantum encryption

  19. The three-wave laser polarimeter-interferometer on J-TEXT tokamak

    Science.gov (United States)

    Zhuang, G.; Liu, Y.; Chen, J.; Gao, L.; Li, Q.; Xiong, C. Y.; Shi, P.; Zhou, Y. N.

    2016-02-01

    Motivated by increasing demands on high-quality measurement of interior magnetic field in tokamak plasma, a far-infrared laser-based polarimeter-interferometer system has been developed on J-TEXT. Three formic acid lasers separately pumped by three CO2 lasers are used as sources, providing more than 90 mW output power in total. High laser power along with usage of newly developed planar Schottky diode mixer enable high phase resolution cross-section of the plasma to provide high spatial resolution measurement. With this system, MHD equilibrium of the J-TEXT plasma has been reconstructed. Obscure perturbations on magnetic topology and electron density associated with MHD instabilities, e.g. sawteeth and tearing modes have also been observed. In particular, some interesting features of disruptions in high-density discharges are identified by carefully interpreting the measured polarimeter-interferometer data. In the density ramp-up phase of a high density discharge, asymmetry in both electron density and current density profiles between the Low-Field-Side (LFS) edge (r > 0.8a) and the High-Field-Side (HFS) edge (r < -0.8a) would appear and extend gradually toward the center region. At the same time, a low-frequency (< 1 kHz) density perturbation suddenly occurs at the HFS edge and also gradually propagates into the center region. The disruption takes place when the electron density asymmetry/perturbation reaches the location nearly the m/n = 2/1 (where m and n are the toroidal mode number and the poloidal one, respectively) resonant surface. Evolution of the reconstructed electron density and current density profiles present the details on the asymmetrical behaviors and provide a possible explanation for the high density disruption.

  20. FPGA-Based X-Ray Detection and Measurement for an X-Ray Polarimeter

    Science.gov (United States)

    Gregory, Kyle; Hill, Joanne; Black, Kevin; Baumgartner, Wayne

    2013-01-01

    This technology enables detection and measurement of x-rays in an x-ray polarimeter using a field-programmable gate array (FPGA). The technology was developed for the Gravitational and Extreme Magnetism Small Explorer (GEMS) mission. It performs precision energy and timing measurements, as well as rejection of non-x-ray events. It enables the GEMS polarimeter to detect precisely when an event has taken place so that additional measurements can be made. The technology also enables this function to be performed in an FPGA using limited resources so that mass and power can be minimized while reliability for a space application is maximized and precise real-time operation is achieved. This design requires a low-noise, charge-sensitive preamplifier; a highspeed analog to digital converter (ADC); and an x-ray detector with a cathode terminal. It functions by computing a sum of differences for time-samples whose difference exceeds a programmable threshold. A state machine advances through states as a programmable number of consecutive samples exceeds or fails to exceed this threshold. The pulse height is recorded as the accumulated sum. The track length is also measured based on the time from the start to the end of accumulation. For track lengths longer than a certain length, the algorithm estimates the barycenter of charge deposit by comparing the accumulator value at the midpoint to the final accumulator value. The design also employs a number of techniques for rejecting background events. This innovation enables the function to be performed in space where it can operate autonomously with a rapid response time. This implementation combines advantages of computing system-based approaches with those of pure analog approaches. The result is an implementation that is highly reliable, performs in real-time, rejects background events, and consumes minimal power.