ACTPol: Status and preliminary CMB polarization results from the Atacama Cosmology Telescope

Science.gov (United States)

Koopman, Brian

2014-03-01

The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive upgrade for the Atacama Cosmology Telescope, located at an elevation of 5190 m on Cerro Toco in Chile. In summer 2013, ACTPol achieved first light with one third of the final detector configuration. The remaining two thirds of the detector array will be installed during spring 2014, enabling full sensitivity, high resolution, observations at both 90 GHz and 150 GHz. Using approximately 3,000 transition-edge sensor bolometers, ACTPol will enable measurements of small angular scale polarization anisotropies in the Cosmic Microwave Background (CMB). I will present a status update for the ACTPol receiver and some preliminary results. ACTPol measurements will allow us to probe the spectral index of inflation as well as to constrain early dark energy and the sum of neutrino masses.

ACCURATE POLARIZATION CALIBRATION AT 800 MHz WITH THE GREEN BANK TELESCOPE

Energy Technology Data Exchange (ETDEWEB)

Liao, Yu-Wei; Chang, Tzu-Ching; Kuo, Cheng-Yu [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astro-Math Building, AS/NTU, 1 Roosevelt Road Sec. 4, Taipei 10617, Taiwan (China); Masui, Kiyoshi Wesley [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (Canada); Oppermann, Niels; Pen, Ue-Li [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto ON, M5S 3H8 (Canada); Peterson, Jeffrey B., E-mail: ywliao@asiaa.sinica.edu.tw [McWilliams Center for Cosmology, Carnegie Mellon University, Department of Physics, 5000 Forbes Avenue, Pittsburgh PA 15213 (United States)

2016-12-20

Polarization leakage of foreground synchrotron emission is a critical issue in H i intensity mapping experiments. While the sought-after H i emission is unpolarized, polarized foregrounds such as Galactic and extragalactic synchrotron radiation, if coupled with instrumental impurity, can mimic or overwhelm the H i signals. In this paper, we present the methodology for polarization calibration at 700–900 MHz, applied on data obtained from the Green Bank Telescope (GBT). We use astrophysical sources, both polarized and unpolarized sources including quasars and pulsars, as calibrators to characterize the polarization leakage and control systematic effects in our GBT H i intensity mapping project. The resulting fractional errors on polarization measurements on boresight are well controlled to within 0.6%–0.8% of their total intensity. The polarized beam patterns are measured by performing spider scans across both polarized quasars and pulsars. A dominant Stokes I to V leakage feature and secondary features of Stokes I to Q and I to U leakages in the 700–900 MHz frequency range are identified. These characterizations are important for separating foreground polarization leakage from the H i 21 cm signal.

ACCURATE POLARIZATION CALIBRATION AT 800 MHz WITH THE GREEN BANK TELESCOPE

International Nuclear Information System (INIS)

Liao, Yu-Wei; Chang, Tzu-Ching; Kuo, Cheng-Yu; Masui, Kiyoshi Wesley; Oppermann, Niels; Pen, Ue-Li; Peterson, Jeffrey B.

2016-01-01

Polarization leakage of foreground synchrotron emission is a critical issue in H i intensity mapping experiments. While the sought-after H i emission is unpolarized, polarized foregrounds such as Galactic and extragalactic synchrotron radiation, if coupled with instrumental impurity, can mimic or overwhelm the H i signals. In this paper, we present the methodology for polarization calibration at 700–900 MHz, applied on data obtained from the Green Bank Telescope (GBT). We use astrophysical sources, both polarized and unpolarized sources including quasars and pulsars, as calibrators to characterize the polarization leakage and control systematic effects in our GBT H i intensity mapping project. The resulting fractional errors on polarization measurements on boresight are well controlled to within 0.6%–0.8% of their total intensity. The polarized beam patterns are measured by performing spider scans across both polarized quasars and pulsars. A dominant Stokes I to V leakage feature and secondary features of Stokes I to Q and I to U leakages in the 700–900 MHz frequency range are identified. These characterizations are important for separating foreground polarization leakage from the H i 21 cm signal.

THE PDS 66 CIRCUMSTELLAR DISK AS SEEN IN POLARIZED LIGHT WITH THE GEMINI PLANET IMAGER

International Nuclear Information System (INIS)

Wolff, Schuyler G.; Greenbaum, Alexandra Z.; Perrin, Marshall; Hines, Dean C.; Millar-Blanchaer, Maxwell A.; Nielsen, Eric L.; Wang, Jason; Dong, Ruobing; Duchêne, Gaspard; Graham, James R.; Kalas, Paul; Cardwell, Andrew; Chilcote, Jeffrey; Draper, Zachary H.; Fitzgerald, Michael P.; Hung, Li-Wei; Goodsell, Stephen J.; Grady, Carol A.; Hartung, Markus; Hibon, Pascale

2016-01-01

We present H- and K-band imaging polarimetry for the PDS 66 circumstellar disk obtained during the commissioning of the Gemini Planet Imager (GPI). Polarization images reveal a clear detection of the disk in to the 0.″12 inner working angle (IWA) in the H band, almost three times closer to the star than the previous Hubble Space Telescope (HST) observations with NICMOS and STIS (0.″35 effective IWA). The centro-symmetric polarization vectors confirm that the bright inner disk detection is due to circumstellar scattered light. A more diffuse disk extends to a bright outer ring centered at 80 AU. We discuss several physical mechanisms capable of producing the observed ring + gap structure. GPI data confirm enhanced scattering on the east side of the disk that is inferred to be nearer to us. We also detect a lateral asymmetry in the south possibly due to shadowing from material within the IWA. This likely corresponds to a temporally variable azimuthal asymmetry observed in HST/STIS coronagraphic imaging

THE PDS 66 CIRCUMSTELLAR DISK AS SEEN IN POLARIZED LIGHT WITH THE GEMINI PLANET IMAGER

Energy Technology Data Exchange (ETDEWEB)

Wolff, Schuyler G.; Greenbaum, Alexandra Z. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Perrin, Marshall; Hines, Dean C. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Millar-Blanchaer, Maxwell A. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Nielsen, Eric L. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Wang, Jason; Dong, Ruobing; Duchêne, Gaspard; Graham, James R.; Kalas, Paul [Astronomy Department, University of California, Berkeley, Berkeley, CA 94720 (United States); Cardwell, Andrew [LBT Observatory, University of Arizona, 933 N. Cherry Avenue, Room 552, Tucson, AZ 85721 (United States); Chilcote, Jeffrey [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Draper, Zachary H. [University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada); Fitzgerald, Michael P.; Hung, Li-Wei [Department of Physics and Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90095 (United States); Goodsell, Stephen J. [Gemini Observatory, 670 N. A’ohoku Place, Hilo, HI 96720 (United States); Grady, Carol A. [Eureka Scientific, 2452 Delmer, Suite 100, Oakland, CA 96002 (United States); Hartung, Markus; Hibon, Pascale, E-mail: swolff9@jh.edu [Gemini Observatory, Casilla 603, La Serena (Chile); and others

2016-02-10

We present H- and K-band imaging polarimetry for the PDS 66 circumstellar disk obtained during the commissioning of the Gemini Planet Imager (GPI). Polarization images reveal a clear detection of the disk in to the 0.″12 inner working angle (IWA) in the H band, almost three times closer to the star than the previous Hubble Space Telescope (HST) observations with NICMOS and STIS (0.″35 effective IWA). The centro-symmetric polarization vectors confirm that the bright inner disk detection is due to circumstellar scattered light. A more diffuse disk extends to a bright outer ring centered at 80 AU. We discuss several physical mechanisms capable of producing the observed ring + gap structure. GPI data confirm enhanced scattering on the east side of the disk that is inferred to be nearer to us. We also detect a lateral asymmetry in the south possibly due to shadowing from material within the IWA. This likely corresponds to a temporally variable azimuthal asymmetry observed in HST/STIS coronagraphic imaging.

POLARIZATION OBSERVATIONS OF 100 PULSARS AT 774 MHz BY THE GREEN BANK TELESCOPE

International Nuclear Information System (INIS)

Han, J. L.; Demorest, P. B.; Van Straten, W.; Lyne, A. G.

2009-01-01

We report on polarimetric observations of 100 pulsars centered on 774 MHz, made using the Green Bank Telescope, presenting their polarization profiles and polarized flux densities and comparing them with previous observations when possible. For 67 pulsars, these are the first such measurements made. Polarization profiles of 8 millisecond-pulsars in our sample show wide profiles and flat position-angle curves. Strong linear polarization, sometimes approaching 100% of the total intensity, has been detected in all or a part of the average pulse profiles of some pulsars. In general, circular polarization is very weak, although it is observed to be extremely strong in the leading component of PSR J1920+2650. Sense reversal of circular polarization as a function of pulse phase has been detected from both core and other components of more than 20 pulsars. Any relationship between the spin-down luminosity and the percentage of linear polarization is not evident in our data at this frequency.

Differential NICMOS Spectrophotometry at High S/N

Science.gov (United States)

Gilliland, Ronald L.

2006-01-01

Transiting extrasolar planets present an opportunity for probing atmospheric conditions and constituents by taking advantage of different apparent radii, hence transit depth as a function of wavelength. Strong near-IR bands should support detection of water vapor via G141 spectroscopy of the bright star HD 209458 (H=6.13) by comparing in- and out-of-transit ratios of in- and out-of-band spectral intensity ratios. The reduction and analysis of science observations in which the goal is to support 1 part in 10,000, or better, development of spectral diagnostics using NICMOS grism-based spectroscopy is discussed.

Deep UV to NIR Space Telescopes and Exoplanet Coronagraphs: A Trade Study on Throughput, Polarization, Mirror Coating Options and Requirements

Science.gov (United States)

Balasubramanian, Kunjithapatham; Shaklan, Stuart; Give'on, Amir; Cady, Eric; Marchen, Luis

2011-01-01

The NASA Exoplanet program and the Cosmic Origins program are exploring technical options to combine the visible to NIR performance requirements of a space coronagraph with the general astrophysics requirements of a space telescope covering the deep UV spectrum. Are there compatible options in terms of mirror coatings and telescope architecture to satisfy both goals? In this paper, we address some of the main concerns, particularly relating to polarization in the visible and throughput in the UV. Telescope architectures employing different coating options compatible with current technology are considered in this trade study.

Hubble Space Telescope Imaging and Spectral Analysis of Two Brown Dwarf Binaries at the L Dwarf/T Dwarf Transition

OpenAIRE

Burgasser, Adam J.; Gagliuffi, Daniella C. Bardalez; Gizis, John E.

2010-01-01

We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space Telescope/NICMOS show opposite trends in the relative colors of the components, with the secondary of 2MASS J0850+1057 being redder than its primary, while that of 2MASS J1728+3948 is bluer. We determine near-infrared component types by matching combined-lig...

EBEX: A Balloon-Borne Telescope for Measuring Cosmic Microwave Background Polarization

Science.gov (United States)

Chapman, Daniel

2015-05-01

EBEX is a long-duration balloon-borne (LDB) telescope designed to probe polarization signals in the cosmic microwave background (CMB). It is designed to measure or place an upper limit on the inflationary B-mode signal, a signal predicted by inflationary theories to be imprinted on the CMB by gravitational waves, to detect the effects of gravitational lensing on the polarization of the CMB, and to characterize polarized Galactic foreground emission. The payload consists of a pointed gondola that houses the optics, polarimetry, detectors and detector readout systems, as well as the pointing sensors, control motors, telemetry sytems, and data acquisition and flight control computers. Polarimetry is achieved with a rotating half-wave plate and wire grid polarizer. The detectors are sensitive to frequency bands centered on 150, 250, and 410 GHz. EBEX was flown in 2009 from New Mexico as a full system test, and then flown again in December 2012 / January 2013 over Antarctica in a long-duration flight to collect scientific data. In the instrumentation part of this thesis we discuss the pointing sensors and attitude determination algorithms. We also describe the real-time map making software, "QuickLook", that was custom-designed for EBEX. We devote special attention to the design and construction of the primary pointing sensors, the star cameras, and their custom-designed flight software package, "STARS" (the Star Tracking Attitude Reconstruction Software). In the analysis part of this thesis we describe the current status of the post-flight analysis procedure. We discuss the data structures used in analysis and the pipeline stages related to attitude determination and map making. We also discuss a custom-designed software framework called "LEAP" (the LDB EBEX Analysis Pipeline) that supports most of the analysis pipeline stages.

Confirmation and characterization of young planetary companions hidden in the HST NICMOS archive

Science.gov (United States)

Pueyo, Laurent

2013-10-01

We propose to conduct WFC3 high contrast observations of six faint planetary candidates orbiting young {1 to 100 Myrs} stars identified in archival HST NICMOS coronagraphic data as part of our team's program AR-12652. Such rare objects are of the utmost importance to comparative exo-planetology as their physical properties reflect the initial conditions of still poorly constrained planetary formation mechanisms. Moreover directly imaged systems are precious artifacts in the expanding exo-planetary treasure trove as they are readily available for spectroscopic characterization. Our statistical analysis, which combines population synthesis models and empirical inspections of the entire NICMOS field of view for all sources observed in coronaraphic mode, almost guarantees that one of these six faint candidates is associated with its putative host star. We will conduct our observation in four near infrared filter, F125W, F160W to establish the baseline luminosity of our candidates and in F127M and F139M in order to probe the depth their water absorption features, characteristic of substellar /exo-planetary like atmospheres. Because of the youth of our targets, this program, which only requires a modest 12 HST orbits, will almost certainly identify and image a young or adolescent exo-planet.

The Atacama Cosmology Telescope: CMB polarization at 200 < ℓ < 9000

Energy Technology Data Exchange (ETDEWEB)

Naess, Sigurd; Allison, Rupert; Calabrese, Erminia [Sub-Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Hasselfield, Matthew [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); McMahon, Jeff; Coughlin, Kevin; Datta, Rahul [Department of Physics, University of Michigan, Ann Arbor 48103 (United States); Niemack, Michael D.; De Bernardis, Francesco [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Addison, Graeme E.; Amiri, Mandana [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Ade, Peter A. R. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, Wales CF24 3AA (United Kingdom); Battaglia, Nick [McWilliams Center for Cosmology, Carnegie Mellon University, Department of Physics, 5000 Forbes Ave., Pittsburgh PA 15213 (United States); Beall, James A.; Britton, Joe; Cho, Hsiao-mei [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); Bond, J Richard [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Crichton, Devin [Dept. of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Das, Sudeep [Department of High Energy Physics, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL 60439 (United States); Devlin, Mark J., E-mail: sigurd.naess@astro.ox.ac.uk [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); and others

2014-10-01

We report on measurements of the cosmic microwave background (CMB) and celestial polarization at 146 GHz made with the Atacama Cosmology Telescope Polarimeter (ACTPol) in its first three months of observing. Four regions of sky covering a total of 270 square degrees were mapped with an angular resolution of 1.3'. The map noise levels in the four regions are between 11 and 17 μK-arcmin. We present TT, TE, EE, TB, EB, and BB power spectra from three of these regions. The observed E-mode polarization power spectrum, displaying six acoustic peaks in the range 200 < ℓ < 3000, is an excellent fit to the prediction of the best-fit cosmological models from WMAP9+ACT and Planck data. The polarization power spectrum, which mainly reflects primordial plasma velocity perturbations, provides an independent determination of cosmological parameters consistent with those based on the temperature power spectrum, which results mostly from primordial density perturbations. We find that without masking any point sources in the EE data at ℓ < 9000, the Poisson tail of the EE power spectrum due to polarized point sources has an amplitude less than 2.4 μ {sup 2} at ℓ = 3000 at 95% confidence. Finally, we report that the Crab Nebula, an important polarization calibration source at microwave frequencies, has 8.7% polarization with an angle of 150.7{sup o} ± 0.6{sup o} when smoothed with a 5' Gaussian beam.

The Atacama Cosmology Telescope: The Polarization-Sensitive ACTPol Instrument

Science.gov (United States)

Thornton, R. J.; Ade, P. A. R.; Aiola, S.; Angile, F. E.; Amiri, M.; Beall, J. A.; Becker, D. T.; Cho, H.-M.; Choi, S. K.; Corlies, P.;

The Atacama Cosmology Telescope: The Polarization-sensitive ACTPol Instrument

Science.gov (United States)

Thornton, R. J.; Ade, P. A. R.; Aiola, S.; Angilè, F. E.; Amiri, M.; Beall, J. A.; Becker, D. T.; Cho, H.-M.; Choi, S. K.; Corlies, P.; Coughlin, K. P.; Datta, R.; Devlin, M. J.; Dicker, S. R.; Dünner, R.; Fowler, J. W.; Fox, A. E.; Gallardo, P. A.; Gao, J.; Grace, E.; Halpern, M.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Hincks, A. D.; Ho, S. P.; Hubmayr, J.; Irwin, K. D.; Klein, J.; Koopman, B.; Li, Dale; Louis, T.; Lungu, M.; Maurin, L.; McMahon, J.; Munson, C. D.; Naess, S.; Nati, F.; Newburgh, L.; Nibarger, J.; Niemack, M. D.; Niraula, P.; Nolta, M. R.; Page, L. A.; Pappas, C. G.; Schillaci, A.; Schmitt, B. L.; Sehgal, N.; Sievers, J. L.; Simon, S. M.; Staggs, S. T.; Tucker, C.; Uehara, M.; van Lanen, J.; Ward, J. T.; Wollack, E. J.

2016-12-01

The Atacama Cosmology Telescope (ACT) makes high angular resolution measurements of anisotropies in the Cosmic Microwave Background (CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3° field of view, 100 mK cryogenics with continuous cooling, and meta material antireflection coatings. ACTPol comprises three arrays with separate cryogenic optics: two arrays at a central frequency of 148 GHz and one array operating simultaneously at both 97 GHz and 148 GHz. The combined instrument sensitivity, angular resolution, and sky coverage are optimized for measuring angular power spectra, clusters via the thermal Sunyaev–Zel’dovich (SZ) and kinetic SZ signals, and CMB lensing due to large-scale structure. The receiver was commissioned with its first 148 GHz array in 2013, observed with both 148 GHz arrays in 2014, and has recently completed its first full season of operations with the full suite of three arrays. This paper provides an overview of the design and initial performance of the receiver and related systems.

Status of the GroundBIRD Telescope

Science.gov (United States)

Choi, J.; Génova-Santos, R.; Hattori, M.; Hazumi, M.; Ishitsuka, H.; Kanno, F.; Karatsu, K.; Kiuchi, K.; Koyano, R.; Kutsuma, H.; Lee, K.; Mima, S.; Minowa, M.; Nagai, M.; Nagasaki, T.; Naruse, M.; Oguri, S.; Okada, T.; Otani, C.; Rebolo, R.; Rubiño-Martín, J.; Sekimoto, Y.; Suzuki, J.; Taino, T.; Tajima, O.; Tomita, N.; Uchida, T.; Won, E.; Yoshida, M.

2018-01-01

Our understanding of physics at very early Universe, as early as 10-35 s after the Big Bang, relies on the scenario known as the inflationary cosmology. Inflation predicts a particular polarization pattern in the cosmic microwave background, known as the B-mode yet the strength of such polarization pattern is extremely weak. To search for the B-mode of the polarization in the cosmic microwave background, we are constructing an off-axis rotating telescope to mitigate systematic effects as well as to maximize the sky coverage of the observation. We will discuss the present status of the GroundBIRD telescope.

New Results from the Magellan IMACS Spectroscopic Lyα Survey: NICMOS Observations of Lyα Emitters at z = 5.7

Science.gov (United States)

Henry, Alaina L.; Martin, Crystal L.; Dressler, Alan; McCarthy, Patrick; Sawicki, Marcin

2010-08-01

We present NICMOS J 110 (rest-frame 1200-2100 Å) observations of the three z = 5.7 Lyα emitters discovered in the blind multislit spectroscopic survey by Martin et al. These images confirm the presence of the two sources that were previously only seen in spectroscopic observations. The third source, which is undetected in our J 110 observations, has been detected in narrowband imaging of the Cosmic Origins Survey, so our non-detection implies a rest-frame equivalent width >146 Å (3σ). The two J 110-detected sources have more modest rest-frame equivalent widths of 30-40 Å, but all three are typical of high-redshift Lyα emitters. In addition, the J 110-detected sources have UV luminosities that are within a factor of 2 of L*UV, and sizes that appear compact (r hl~ 0farcs15) in our NIC2 images—consistent with a redshift of 5.7. We use these UV-continuum and Lyα measurements to estimate the i 775-z 850 colors of these galaxies and show that at least one and possibly all three would be missed by the i-dropout Lyman break galaxy selection. These observations help demonstrate the utility of multislit narrowband spectroscopy as a technique for finding faint emission-line galaxies. This work is based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained 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. These observations are associated with proposal 11183.

Status of the GroundBIRD Telescope

Directory of Open Access Journals (Sweden)

Choi J.

2018-01-01

Full Text Available Our understanding of physics at very early Universe, as early as 10−35 s after the Big Bang, relies on the scenario known as the inflationary cosmology. Inflation predicts a particular polarization pattern in the cosmic microwave background, known as the B-mode yet the strength of such polarization pattern is extremely weak. To search for the B-mode of the polarization in the cosmic microwave background, we are constructing an off-axis rotating telescope to mitigate systematic effects as well as to maximize the sky coverage of the observation. We will discuss the present status of the GroundBIRD telescope.

Detection of B-mode polarization in the cosmic microwave background with data from the South Pole Telescope.

Science.gov (United States)

Hanson, D; Hoover, S; Crites, A; Ade, P A R; Aird, K A; Austermann, J E; Beall, J A; Bender, A N; Benson, B A; Bleem, L E; Bock, J J; Carlstrom, J E; Chang, C L; Chiang, H C; Cho, H-M; Conley, A; Crawford, T M; de Haan, T; Dobbs, M A; Everett, W; Gallicchio, J; Gao, J; George, E M; Halverson, N W; Harrington, N; Henning, J W; Hilton, G C; Holder, G P; Holzapfel, W L; Hrubes, J D; Huang, N; Hubmayr, J; Irwin, K D; Keisler, R; Knox, L; Lee, A T; Leitch, E; Li, D; Liang, C; Luong-Van, D; Marsden, G; McMahon, J J; Mehl, J; Meyer, S S; Mocanu, L; Montroy, T E; Natoli, T; Nibarger, J P; Novosad, V; Padin, S; Pryke, C; Reichardt, C L; Ruhl, J E; Saliwanchik, B R; Sayre, J T; Schaffer, K K; Schulz, B; Smecher, G; Stark, A A; Story, K T; Tucker, C; Vanderlinde, K; Vieira, J D; Viero, M P; Wang, G; Yefremenko, V; Zahn, O; Zemcov, M

2013-10-04

Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7σ significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.

z ∼ 7 GALAXY CANDIDATES FROM NICMOS OBSERVATIONS OVER THE HDF-SOUTH AND THE CDF-SOUTH AND HDF-NORTH GOODS FIELDS

International Nuclear Information System (INIS)

Bouwens, Rychard J.; Illingworth, Garth D.; Gonzalez, Valentino; Holden, Brad; Magee, Dan; Labbe, Ivo; Franx, Marijn; Conselice, Christopher J.; Blakeslee, John; Van Dokkum, Pieter; Marchesini, Danilo; Zheng Wei

2010-01-01

We use ∼88 arcmin 2 of deep (∼>26.5 mag at 5σ) NICMOS data over the two GOODS fields and the HDF-South to conduct a search for bright z ∼> 7 galaxy candidates. This search takes advantage of an efficient preselection over 58 arcmin 2 of NICMOS H 160 -band data where only plausible z ∼> 7 candidates are followed up with NICMOS J 110 -band observations. ∼248 arcmin 2 of deep ground-based near-infrared data (∼>25.5 mag, 5σ) are also considered in the search. In total, we report 15 z 850 -dropout candidates over this area-7 of which are new to these search fields. Two possible z ∼ 9 J 110 -dropout candidates are also found, but seem unlikely to correspond to z ∼ 9 galaxies (given the estimated contamination levels). The present z ∼ 9 search is used to set upper limits on the prevalence of such sources. Rigorous testing is undertaken to establish the level of contamination of our selections by photometric scatter, low-mass stars, supernovae, and spurious sources. The estimated contamination rate of our z ∼ 7 selection is ∼24%. Through careful simulations, the effective volume available to our z ∼> 7 selections is estimated and used to establish constraints on the volume density of luminous (L* z =3 , or ∼-21 mag) galaxies from these searches. We find that the volume density of luminous star-forming galaxies at z ∼ 7 is 13 +8 -5 times lower than at z ∼ 4 and >25 times lower (1σ) at z ∼ 9 than at z ∼ 4. This is the most stringent constraint yet available on the volume density of ∼>L* z =3 galaxies at z ∼ 9. The present wide-area, multi-field search limits cosmic variance to ∼ 850 -dropout sample (18 candidates) identified from all NICMOS observations to date (over the two GOODS fields, the HUDF, galaxy clusters).

Hubble Space Telescope: The Telescope, the Observations & the Servicing Mission

Science.gov (United States)

1999-11-01

replaced by COSTAR. During the second Servicing Mission instruments and other equipment were repaired and updated. The Space Telescope Imaging Spectrograph (STIS) replaced the Goddard High Resolution Spectrograph (GHRS) and the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) replaced the Faint Object Spectrograph (FOS). Servicing mission 3A The original Servicing Mission 3 (initially planned for June 2000) has been split into two missions - SM3A and SM3B - due in part to its complexity, and in part to the urgent need to replace the failed gyroscopes on board. Three gyroscopes must function to meet the telescope's very precise pointing requirements. With only two new operational, observations have had to be suspended, but the telescope will remain safely in orbit until the servicing crew arrives. During this servicing mission * all six gyroscopes will be replaced, * a Fine Guidance Sensor will be replaced, * the spacecraft's computer will be replaced by a new one which will reduce the burden of flight software maintenance and significantly lower costs, * six voltage/temperature kits will be installed to protect spacecraft batteries from overcharging and overheating if the spacecraft enters safe mode, * a new S-Band Single Access Transmitter will replace a failed spare currently aboard the spacecraft, * a solid-state recorder will be installed to replace the tape recorder, * degraded telescope thermal insulation will be replaced if time allows; this insulation is necessary to control the internal temperature on HST. For the mission to be fully successful the gyroscopes, the Fine Guidance Sensor, the computer and the voltage/temperature kits must be installed. The minimum mission success criterion is that HST will have 5 operational gyros after the mission, 4 of them newly installed. The Future During SM3B (presently scheduled for 2001) the astronauts will replace the Faint Object Camera with the Advanced Camera for Surveys (ACS), install a cooling system for

THE SEARCH FOR PLANETARY MASS COMPANIONS TO FIELD BROWN DWARFS WITH HST/NICMOS

International Nuclear Information System (INIS)

Stumpf, M. B.; Brandner, W.; Joergens, V.; Henning, Th.; Bouy, H.; Koehler, R.; Kasper, M.

2010-01-01

We present the results of a high-resolution spectral differential imaging survey of 12 nearby, relatively young field L dwarfs (≤1 Gyr) carried out with the Hubble Space Telescope/NICMOS to search for planetary mass companions at small physical separations from their host. The survey resolved two brown dwarf binaries: the L dwarf system Kelu-1 AB and the newly discovered L/T transition system 2MASS 031059+164815 AB. For both systems, common proper motion has already been confirmed in follow-up observations which have been published elsewhere. The derived separations of the binaries are smaller than 6 AU and consistent with previous brown dwarf binary statistics. Their mass ratios of q ≥ 0.8 confirm the preference for equal-mass systems similar to a large number of other surveys. Furthermore, we found tentative evidence for a companion to the L4 dwarf 2MASSW 033703-175807, straddling the brown dwarf/planetary mass boundary and revealing an uncommonly low-mass ratio system (q ∼ 0.2) compared to the vast majority of previously found brown dwarf binaries. With a derived minimum mass of 10-15 M Jup a planetary nature of the secondary cannot be ruled out yet. However, it seems more likely to be a very low mass brown dwarf secondary at the border of the spectral T/Y transition regime, primarily due to its similarities to recently found very cool T dwarfs. This would make it one of the closest resolved brown dwarf binaries (0.''087 ± 0.''015, corresponding to 2.52 ± 0.44 AU at a distance of 29 pc) with the coolest (T eff ∼ 600-630 K) and least massive companion to any L or T dwarf.

Central Structural Parameters of Early-Type Galaxies as Viewed with Nicmos on the Hubble Space Telescope

Science.gov (United States)

Ravindranath, Swara; Ho, Luis C.; Peng, Chien Y.; Filippenko, Alexei V.; Sargent, Wallace L. W.

2001-08-01

We present surface photometry for the central regions of a sample of 33 early-type (E, S0, and S0/a) galaxies observed at 1.6 μm (H band) using the Hubble Space Telescope. Dust absorption has less of an impact on the galaxy morphologies in the near-infrared than found in previous work based on observations at optical wavelengths. When present, dust seems to be most commonly associated with optical line emission. We employ a new technique of two-dimensional fitting to extract quantitative parameters for the bulge light distribution and nuclear point sources, taking into consideration the effects of the point-spread function. By parameterizing the bulge profile with a Nuker law, we confirm that the central surface brightness distributions largely fall into two categories, each of which correlates with the global properties of the galaxies. ``Core'' galaxies tend to be luminous elliptical galaxies with boxy or pure elliptical isophotes, whereas ``power-law'' galaxies are preferentially lower luminosity systems with disky isophotes. The infrared surface brightness profiles are very similar to those in the optical, with notable exceptions being very dusty objects. Similar to the study of Faber et al., based on optical data, we find that galaxy cores obey a set of fundamental plane relations wherein more luminous galaxies with higher central stellar velocity dispersions generally possess larger cores with lower surface brightnesses. Unlike most previous studies, however, we do not find a clear gap in the distribution of inner cusp slopes; several objects have inner cusp slopes (0.3law galaxies. The nature of these intermediate objects is unclear. We draw attention to two objects in the sample that appear to be promising cases of galaxies with isothermal cores that are not the brightest members of a cluster. Unresolved nuclear point sources are found in ~50% of the sample galaxies, roughly independent of profile type, with magnitudes in the range mnucH=12.8 to 17.4 mag

Solar Spectral Lines with Special Polarization Properties for the Calibration of Instrument Polarization

Energy Technology Data Exchange (ETDEWEB)

Li, W.; Casini, R.; Alemán, T. del Pino; Judge, P. G. [High Altitude Observatory, National Center for Atmospheric Research 1, P.O. Box 3000, Boulder, CO 80307-3000 (United States)

2017-10-20

We investigate atomic transitions that have previously been identified as having zero polarization from the Zeeman effect. Our goal is to identify spectral lines that can be used for the calibration of instrumental polarization of large astronomical and solar telescopes, such as the Daniel K. Inouye Solar Telescope, which is currently under construction on Haleakala. We use a numerical model that takes into account the generation of scattering polarization and its modification by the presence of a magnetic field of arbitrary strength. We adopt values for the Landé factors from spectroscopic measurements or semi-empirical results, thus relaxing the common assumption of LS-coupling previously used in the literature. The mechanisms dominating the polarization of particular transitions are identified, and we summarize groups of various spectral lines useful for the calibration of spectropolarimetric instruments, classified according to their polarization properties.

Automated Polarimetry with Smaller Aperture Telescopes: The ROVOR Observatory

Directory of Open Access Journals (Sweden)

Joseph Moody

2017-10-01

Full Text Available To better understand possible blazar jet mechanisms and morphologies, brighter prototypical objects are regularly monitored for variability in optical broad-band light. If the monitoring filters are polarized, the position angles and polarization percentages can be measured and their evolution monitored over time. However, building up a statistically significant time base of polarization parameters requires the arduous task of monitoring sources for months or years to catch and follow interesting events such as flares. Fortunately, monitoring an object is easily done using remotely operated or robotic telescopes. The Remote Observatory for Variable Object Research (ROVOR is a small-aperture telescope that has monitored blazars in broad-band Johnson filters since 2009. Calibration data using a set of four plane-polarized filters suggest that it is suitable for polarimetric monitoring as well. We have successfully collected data on CTA 102 and are encouraged at the prospects of monitoring it and other similar objects. Long-term monitoring campaigns are a scientifically and educationally-effective use of underutilized smaller-aperture telescopes.

Optimal networks of future gravitational-wave telescopes

Science.gov (United States)

Raffai, Péter; Gondán, László; Heng, Ik Siong; Kelecsényi, Nándor; Logue, Josh; Márka, Zsuzsa; Márka, Szabolcs

2013-08-01

We aim to find the optimal site locations for a hypothetical network of 1-3 triangular gravitational-wave telescopes. We define the following N-telescope figures of merit (FoMs) and construct three corresponding metrics: (a) capability of reconstructing the signal polarization; (b) accuracy in source localization; and (c) accuracy in reconstructing the parameters of a standard binary source. We also define a combined metric that takes into account the three FoMs with practically equal weight. After constructing a geomap of possible telescope sites, we give the optimal 2-telescope networks for the four FoMs separately in example cases where the location of the first telescope has been predetermined. We found that based on the combined metric, placing the first telescope to Australia provides the most options for optimal site selection when extending the network with a second instrument. We suggest geographical regions where a potential second and third telescope could be placed to get optimal network performance in terms of our FoMs. Additionally, we use a similar approach to find the optimal location and orientation for the proposed LIGO-India detector within a five-detector network with Advanced LIGO (Hanford), Advanced LIGO (Livingston), Advanced Virgo, and KAGRA. We found that the FoMs do not change greatly in sites within India, though the network can suffer a significant loss in reconstructing signal polarizations if the orientation angle of an L-shaped LIGO-India is not set to the optimal value of ˜58.2°( + k × 90°) (measured counterclockwise from East to the bisector of the arms).

The Secret Lives of Galaxies

Science.gov (United States)

2001-01-01

The ground-based image in visible light locates the hub imaged with the Hubble Space Telescope. This barred galaxy feeds material into its hub, igniting star birth. The Hubble NICMOS instrument penetrates beneath the dust to reveal clusters of young stars. Footage shows ground-based, WFPC2, and NICMOS images of NGS 1365. An animation of a large spiral galaxy zooms from the edge to the galactic bulge.

Optimal networks of future gravitational-wave telescopes

International Nuclear Information System (INIS)

Raffai, Péter; Márka, Zsuzsa; Márka, Szabolcs; Gondán, László; Kelecsényi, Nándor; Heng, Ik Siong; Logue, Josh

2013-01-01

We aim to find the optimal site locations for a hypothetical network of 1–3 triangular gravitational-wave telescopes. We define the following N-telescope figures of merit (FoMs) and construct three corresponding metrics: (a) capability of reconstructing the signal polarization; (b) accuracy in source localization; and (c) accuracy in reconstructing the parameters of a standard binary source. We also define a combined metric that takes into account the three FoMs with practically equal weight. After constructing a geomap of possible telescope sites, we give the optimal 2-telescope networks for the four FoMs separately in example cases where the location of the first telescope has been predetermined. We found that based on the combined metric, placing the first telescope to Australia provides the most options for optimal site selection when extending the network with a second instrument. We suggest geographical regions where a potential second and third telescope could be placed to get optimal network performance in terms of our FoMs. Additionally, we use a similar approach to find the optimal location and orientation for the proposed LIGO-India detector within a five-detector network with Advanced LIGO (Hanford), Advanced LIGO (Livingston), Advanced Virgo, and KAGRA. We found that the FoMs do not change greatly in sites within India, though the network can suffer a significant loss in reconstructing signal polarizations if the orientation angle of an L-shaped LIGO-India is not set to the optimal value of ∼58.2°( + k × 90°) (measured counterclockwise from East to the bisector of the arms). (paper)

Novel optical scanning cryptography using Fresnel telescope imaging.

Science.gov (United States)

Yan, Aimin; Sun, Jianfeng; Hu, Zhijuan; Zhang, Jingtao; Liu, Liren

2015-07-13

We propose a new method called modified optical scanning cryptography using Fresnel telescope imaging technique for encryption and decryption of remote objects. An image or object can be optically encrypted on the fly by Fresnel telescope scanning system together with an encryption key. For image decryption, the encrypted signals are received and processed with an optical coherent heterodyne detection system. The proposed method has strong performance through use of secure Fresnel telescope scanning with orthogonal polarized beams and efficient all-optical information processing. The validity of the proposed method is demonstrated by numerical simulations and experimental results.

Polarization Properties of 24 Fermi-Detected Blazars

Science.gov (United States)

Linford, Justin; Taylor, G. B.; Schinzel, F. K.; Zavala, R. T.

2013-01-01

Gamma-ray emitting blazars have been shown to frequently have significant polarization at radio wavelengths. In early 2012, we obtained Very Long Baseline Array (VLBA) observations of 24 blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. These observations utilized the new 2 gigabit-per-second mode of the VLBA. We observed each source with full polarization at 8.4 GHz, 15 GHz, and 22 GHz with 256 MHz of total bandwidth per polarization. Our sample contains 14 flat-spectrum radio quasars (FSRQs) and 10 BL Lacertae objects (BL Lacs). We analyze the spectral index, rotation measure, and magnetic field structures of these 24 gamma-ray loud blazars.

Observing the Cosmic Microwave Background Polarization with Variable-delay Polarization Modulators for the Cosmology Large Angular Scale Surveyor

Science.gov (United States)

Harrington, Kathleen; CLASS Collaboration

2018-01-01

The search for inflationary primordial gravitational waves and the optical depth to reionization, both through their imprint on the large angular scale correlations in the polarization of the cosmic microwave background (CMB), has created the need for high sensitivity measurements of polarization across large fractions of the sky at millimeter wavelengths. These measurements are subjected to instrumental and atmospheric 1/f noise, which has motivated the development of polarization modulators to facilitate the rejection of these large systematic effects.Variable-delay polarization modulators (VPMs) are used in the Cosmology Large Angular Scale Surveyor (CLASS) telescopes as the first element in the optical chain to rapidly modulate the incoming polarization. VPMs consist of a linearly polarizing wire grid in front of a moveable flat mirror; varying the distance between the grid and the mirror produces a changing phase shift between polarization states parallel and perpendicular to the grid which modulates Stokes U (linear polarization at 45°) and Stokes V (circular polarization). The reflective and scalable nature of the VPM enables its placement as the first optical element in a reflecting telescope. This simultaneously allows a lock-in style polarization measurement and the separation of sky polarization from any instrumental polarization farther along in the optical chain.The Q-Band CLASS VPM was the first VPM to begin observing the CMB full time in 2016. I will be presenting its design and characterization as well as demonstrating how modulating polarization significantly rejects atmospheric and instrumental long time scale noise.

HUBBLE SPACE TELESCOPE IMAGING AND SPECTRAL ANALYSIS OF TWO BROWN DWARF BINARIES AT THE L DWARF/T DWARF TRANSITION

International Nuclear Information System (INIS)

Burgasser, Adam J.; Bardalez-Gagliuffi, Daniella C.; Gizis, John E.

2011-01-01

We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space Telescope/NICMOS shows opposite trends in the relative colors of the components, with the secondary of 2MASS J0850+1057 being redder than its primary, while that of 2MASS J1728+3948 is bluer. We determine near-infrared component types by matching combined-light, near-infrared spectral data to binary templates, with component spectra scaled to resolved NICMOS and K p photometry. Combinations of L7 + L6 for 2MASS J0850+1057 and L5 + L6.5 for 2MASS J1728+3948 are inferred. Remarkably, the primary of 2MASS J0850+1057 appears to have a later-type classification compared to its secondary, despite being 0.8-1.2 mag brighter in the near-infrared, while the primary of 2MASS J1728+3948 is unusually early for its combined-light optical classification. Comparison to absolute magnitude/spectral type trends also distinguishes these components, with 2MASS J0850+1057A being ∼1 mag brighter and 2MASS J1728+3948A ∼ 0.5 mag fainter than equivalently classified field counterparts. We deduce that thick condensate clouds are likely responsible for the unusual properties of 2MASS J1728+3948A, while 2MASS J0850+1057A is either an inflated young brown dwarf or a tight unresolved binary, making it potentially part of a wide, low-mass, hierarchical quintuple system.

Polarimeters for the AGS polarized-proton beam

Energy Technology Data Exchange (ETDEWEB)

Crabb, D.G.; Bonner, B.; Buchanan, J.

1983-01-01

This report describes the three polarimeters which will be used to measure the beam polarization at the AGS polarized beam facility. The beam polarization will be measured before injection into the AGS, during acceleration, and after extraction from the AGS. The 200-MeV polarimeter uses scintillation-counter telescopes to measure the asymmetry in p-carbon inclusive scattering. The internal polarimeter can measure the beam polarization at up to five selected times during acceleration. A continuously spooled nylon filament is swung into the beam at the appropriate time and the asymmetry in pp elastic scattering measured by two scintillation-counter telescopes. This is a relative polarimeter which can be calibrated by the absolute external polarimeter located in the D extracted-beam line. This polarimeter uses scintillation counters in two double-arm magnetic spectrometers to measure clearly the asymmetry in pp elastic scattering from a liquid hydrogen target. The specific features and operation of each polarimeter will be discussed.

Polarimeters for the AGS polarized-proton beam

International Nuclear Information System (INIS)

Crabb, D.G.; Bonner, B.; Buchanan, J.

1983-01-01

This report describes the three polarimeters which will be used to measure the beam polarization at the AGS polarized beam facility. The beam polarization will be measured before injection into the AGS, during acceleration, and after extraction from the AGS. The 200-MeV polarimeter uses scintillation-counter telescopes to measure the asymmetry in p-carbon inclusive scattering. The internal polarimeter can measure the beam polarization at up to five selected times during acceleration. A continuously spooled nylon filament is swung into the beam at the appropriate time and the asymmetry in pp elastic scattering measured by two scintillation-counter telescopes. This is a relative polarimeter which can be calibrated by the absolute external polarimeter located in the D extracted-beam line. This polarimeter uses scintillation counters in two double-arm magnetic spectrometers to measure clearly the asymmetry in pp elastic scattering from a liquid hydrogen target. The specific features and operation of each polarimeter will be discussed

Fast Fourier transform telescope

International Nuclear Information System (INIS)

Tegmark, Max; Zaldarriaga, Matias

2009-01-01

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

Telescopic observations - Visual, photographic, polarimetric. [of planet Mars

Science.gov (United States)

Martin, Leonard J.; James, Philip B.; Dollfus, Audouin; Iwasaki, Kyosuke; Beish, Jeffrey D.

1992-01-01

The paper divides the high points of telescopic observations of Mars into three time periods: historical, missions support (recent), and present. Particular attention is given to visual and photographic observations, with brief discussions of spectroscopic and polarization studies. Major topics of Martian phenomena included are albedo features, polar caps, dust storms, and white clouds. The interannual variability of the recessions of seasonal polar caps has been compared to dust storm activity, but this relationship remains uncertain. Only a very limited number of canals can be related to markings on the Viking images. The remainder are argued to be optical illusions created by observers pushing their perceived resolution beyond practical limits.

QUASAR PG1115+080 AND GRAVITATIONAL LENS

Science.gov (United States)

2002-01-01

Left: The light from the single quasar PG 1115+080 is split and distorted in this infrared image. PG 1115+080 is at a distance of about 8 billion light years in the constellation Leo, and it is viewed through an elliptical galaxy lens at a distance of 3 billion light years. The NICMOS frame is taken at a wavelength of 1.6 microns and it shows the four images of the quasar (the two on the left are nearly merging) surrounding the galaxy that causes the light to be lensed. The quasar is a variable light source and the light in each image travels a different path to reach the Earth. The time delay of the variations allows the distance scale to be measured directly. The linear streaks on the image are diffraction artifacts in the NICMOS instrument (NASA/Space Telescope Science Institute). Right: In this NICMOS image, the four quasar images and the lens galaxy have been subtracted, revealing a nearly complete ring of infrared light. This ring is the stretched and amplified starlight of the galaxy that contains the quasar, some 8 billion light years away. (NASA/Space Telescope Science Institute). Credit: Christopher D. Impey (University of Arizona)

Active control of the Chinese Giant Solar Telescope

Science.gov (United States)

Dai, Yichun; Yang, Dehua; Jin, Zhenyu; Liu, Zhong; Qin, Wei

2014-07-01

The Chinese Giant Solar Telescope (CGST) is the next generation solar telescope of China with diameter of 8 meter. The unique feature of CGST is that its primary is a ring, which facilitates the polarization detection and thermal control. In its present design and development phase, two primary mirror patterns are considered. For one thing, the primary mirror is expected to construct with mosaic mirror with 24 trapezoidal (or petal) segments, for another thing, a monolithic mirror is also a candidate for its primary mirror. Both of them depend on active control technique to maintain the optical quality of the ring mirror. As a solar telescope, the working conditions of the CGST are quite different from those of the stellar telescopes. To avoid the image deterioration due to the mirror seeing and dome seeing, especially in the case of the concentration of flux in a solar telescope, large aperture solar projects prefer to adopt open telescopes and open domes. In this circumstance, higher wind loads act on the primary mirror directly, which will cause position errors and figure errors of the primary with matters worse than those of the current 10-meter stellar telescopes with dome protect. Therefore, it gives new challenges to the active control capability, telescope structure design, and wind shielding design. In this paper, the study progress of active control of CGST for its mosaic and monolithic mirror are presented, and the wind effects on such two primary mirrors are also investigated.

Investigating circular patterns in linear polarization observations of Venus

NARCIS (Netherlands)

Mahapatra, G.; Stam, D.M.; Rossi, L.C.G.; Rodenhuis, M.; Snik, Frans; Keller, C.U.

2017-01-01

In this work, we analyse linear polarization data of the planet at a distance, obtained with the Extreme Polarimeter (ExPo) on the William Herschel Telescope
on La Palma. These spatially resolved, high-accuracy polarization observations of Venus show faint circular patterns centered on the

GREEN BANK TELESCOPE DETECTION OF POLARIZATION-DEPENDENT H I ABSORPTION AND H I OUTFLOWS IN LOCAL ULIRGs AND QUASARS

Energy Technology Data Exchange (ETDEWEB)

Teng, Stacy H. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Veilleux, Sylvain [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Baker, Andrew J., E-mail: stacy.h.teng@nasa.gov [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States)

2013-03-10

We present the results of a 21 cm H I survey of 27 local massive gas-rich late-stage mergers and merger remnants with the Robert C. Byrd Green Bank Telescope. These remnants were selected from the Quasar/ULIRG Evolution Study sample of ultraluminous infrared galaxies (ULIRGs; L{sub 8{sub -{sub 1000{sub {mu}m}}}} > 10{sup 12} L{sub Sun }) and quasars; our targets are all bolometrically dominated by active galactic nuclei (AGNs) and sample the later phases of the proposed ULIRG-to-quasar evolutionary sequence. We find the prevalence of H I absorption (emission) to be 100% (29%) in ULIRGs with H I detections, 100% (88%) in FIR-strong quasars, and 63% (100%) in FIR-weak quasars. The absorption features are associated with powerful neutral outflows that change from being mainly driven by star formation in ULIRGs to being driven by the AGN in the quasars. These outflows have velocities that exceed 1500 km s{sup -1} in some cases. Unexpectedly, we find polarization-dependent H I absorption in 57% of our spectra (88% and 63% of the FIR-strong and FIR-weak quasars, respectively). We attribute this result to absorption of polarized continuum emission from these sources by foreground H I clouds. About 60% of the quasars displaying polarized spectra are radio-loud, far higher than the {approx}10% observed in the general AGN population. This discrepancy suggests that radio jets play an important role in shaping the environments in these galaxies. These systems may represent a transition phase in the evolution of gas-rich mergers into ''mature'' radio galaxies.

The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

Science.gov (United States)

Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.;

The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

Science.gov (United States)

Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Hubmayr, J.; Koopman, B. J.; Lanen, J. V.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Ward, J. T.; Wollack, E. J.; Vavagiakis, E. M.

2016-08-01

The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive receiver for the 6-m Atacama Cosmology Telescope (ACT) and measures the small angular scale polarization anisotropies in the cosmic microwave background (CMB). The full focal plane is composed of three detector arrays, containing over 3000 transition edge sensors (TES detectors) in total. The first two detector arrays, observing at 146 GHz, were deployed in 2013 and 2014, respectively. The third and final array is composed of multichroic pixels sensitive to both 90 and 146 GHz and saw first light in February 2015. Fabricated at NIST, this dichroic array consists of 255 pixels, with a total of 1020 polarization sensitive bolometers and is coupled to the telescope with a monolithic array of broad-band silicon feedhorns. The detectors are read out using time-division SQUID multiplexing and cooled by a dilution refrigerator at 110 mK. We present an overview of the assembly and characterization of this multichroic array in the lab, and the initial detector performance in Chile. The detector array has a TES detector electrical yield of 85 %, a total array sensitivity of less than 10 \\upmu K√{ {s}}, and detector time constants and saturation powers suitable for ACT CMB observations.

Design considerations for large detector arrays on submillimeter-wave telescopes

Science.gov (United States)

Stark, Antony A.

2000-07-01

The emerging technology of large (approximately 10,000 pixel) submillimeter-wave bolometer arrays presents a novel optical design problem -- how can such arrays be fed by diffraction- limited telescope optics where the primary mirror is less than 100,000 wavelengths in diameter? Standard Cassegrain designs for radiotelescope optics exhibit focal surface curvature so large that detectors cannot be placed more than 25 beam diameters from the central ray. The problem is worse for Ritchey-Chretien designs, because these minimize coma while increasing field curvature. Classical aberrations, including coma, are usually dominated by diffraction in submillimeter- wave single dish telescopes. The telescope designer must consider (1) diffraction, (2) aberration, (3) curvature of field, (4) cross-polarization, (5) internal reflections, (6) the effect of blockages, (7) means of beam chopping on- and off-source, (8) gravitational and thermal deformations of the primary mirror, (9) the physical mounting of large detector packages, and (10) the effect of gravity and (11) vibration on those detectors. Simultaneous optimization of these considerations in the case of large detector arrays leads to telescopes that differ considerably from standard radiotelescope designs. Offset optics provide flexibility for mounting detectors, while eliminating blockage and internal reflections. Aberrations and cross-polarization can be the same as on-axis designs having the same diameter and focal length. Trade-offs include the complication of primary mirror homology and an increase in overall cost. A dramatic increase in usable field of view can be achieved using shaped optics. Solutions having one to six mirrors will be discussed, including possible six-mirror design for the proposed South Pole 10 m telescope.

Polarization modeling and predictions for DKIST part 2: application of the Berreman calculus to spectral polarization fringes of beamsplitters and crystal retarders

Science.gov (United States)

Harrington, David M.; Snik, Frans; Keller, Christoph U.; Sueoka, Stacey R.; van Harten, Gerard

2017-10-01

We outline polarization fringe predictions derived from an application of the Berreman calculus for the Daniel K. Inouye Solar Telescope (DKIST) retarder optics. The DKIST retarder baseline design used six crystals, single-layer antireflection coatings, thick cover windows, and oil between all optical interfaces. This tool estimates polarization fringes and optic Mueller matrices as functions of all optical design choices. The amplitude and period of polarized fringes under design changes, manufacturing errors, tolerances, and several physical factors can now be estimated. This tool compares well with observations of fringes for data collected with the spectropolarimeter for infrared and optical regions at the Dunn Solar Telescope using bicrystalline achromatic retarders as well as laboratory tests. With this tool, we show impacts of design decisions on polarization fringes as impacted by antireflection coatings, oil refractive indices, cover window presence, and part thicknesses. This tool helped DKIST decide to remove retarder cover windows and also recommends reconsideration of coating strategies for DKIST. We anticipate this tool to be essential in designing future retarders for mitigation of polarization and intensity fringe errors in other high spectral resolution astronomical systems.

Development of atmospheric polarization LIDAR System

International Nuclear Information System (INIS)

Ghalumyan, A.S.; Ghazaryan, V.R.

2016-01-01

LIDAR (Light Detection And Ranging) system sensitive to the polarization of the backscattered signal is being developed in Yerevan Physics Institute. The system is designed primarily for remote sensing of the atmospheric electric fields. At present, the system is being tuned for measuring vertical atmospheric backscatter profiles of aerosols and hydrometeors, analyze the depolarization ratio of elastic backscattered laser beams and investigate the influence of external factors on the beam polarization. In this paper, we describe the complete LIDAR system – the laser transmitter, receiving telescope and the polarization separator. The data acquisition and processing techniques are also described. (author)

Construction of the Advanced Technology Solar Telescope

Science.gov (United States)

Rimmele, T. R.; Keil, S.; McMullin, J.; Knölker, M.; Kuhn, J. R.; Goode, P. R.; Rosner, R.; Casini, R.; Lin, H.; Tritschler, A.; Wöger, F.; ATST Team

2012-12-01

The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. The project has entered its construction phase. Major subsystems have been contracted. As its highest priority science driver ATST shall provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. With its 4m aperture, ATST will resolve features at 0.″03 at visible wavelengths and obtain 0.″1 resolution at the magnetically highly sensitive near infrared wavelengths. A high order adaptive optics system delivers a corrected beam to the initial set of state-of-the-art, facility class instrumentation located in the Coudé laboratory facility. The initial set of first generation instruments consists of five facility class instruments, including imagers and spectro-polarimeters. The high polarimetric sensitivity and accuracy required for measurements of the illusive solar magnetic fields place strong constraints on the polarization analysis and calibration. Development and construction of a four-meter solar telescope presents many technical challenges, including thermal control of the enclosure, telescope structure and optics and wavefront control. A brief overview of the science goals and observational requirements of the ATST will be given, followed by a summary of the design status of the telescope and its instrumentation, including design status of major subsystems, such as the telescope mount assembly, enclosure, mirror assemblies, and wavefront correction

Science Flight Program of the Nuclear Compton Telescope

Science.gov (United States)

Boggs, Steven

This is the lead proposal for this program. We are proposing a 5-year program to perform the scientific flight program of the Nuclear Compton Telescope (NCT), consisting of a series of three (3) scientific balloon flights. NCT is a balloon-borne, wide-field telescope designed to survey the gamma-ray sky (0.2-5 MeV), performing high-resolution spectroscopy, wide-field imaging, and polarization measurements. NCT has been rebuilt as a ULDB payload under the current 2-year APRA grant. (In that proposal we stated our goal was to return at this point to propose the scientific flight program.) The NCT rebuild/upgrade is on budget and schedule to achieve flight-ready status in Fall 2013. Science: NCT will map the Galactic positron annihilation emission, shedding more light on the mysterious concentration of this emission uncovered by INTEGRAL. NCT will survey Galactic nucleosynthesis and the role of supernova and other stellar populations in the creation and evolution of the elements. NCT will map 26-Al and positron annihilation with unprecedented sensitivity and uniform exposure, perform the first mapping of 60-Fe, search for young, hidden supernova remnants through 44-Ti emission, and enable a host of other nuclear astrophysics studies. NCT will also study compact objects (in our Galaxy and AGN) and GRBs, providing novel measurements of polarization as well as detailed spectra and light curves. Design: NCT is an array of germanium gamma-ray detectors configured in a compact, wide-field Compton telescope configuration. The array is shielded on the sides and bottom by an active anticoincidence shield but is open to the 25% of the sky above for imaging, spectroscopy, and polarization measurements. The instrument is mounted on a zenith-pointed gondola, sweeping out ~50% of the sky each day. This instrument builds off the Compton telescope technique pioneered by COMPTEL on the Compton Gamma Ray Observatory. However, by utilizing modern germanium semiconductor strip detectors

Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

Directory of Open Access Journals (Sweden)

Alice K. Harding

2013-09-01

Full Text Available Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. Particle acceleration and high-energy emission from the polar caps is expected to occur in connection with electron-positron pair cascades. I will review acceleration and gamma-ray emission from the pulsar polar cap and associated slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting, population synthesis and phase-resolved spectroscopy.

A determination of H-0 with the class gravitational lens B1608+656. II. Mass models and the Hubble constant from lensing

NARCIS (Netherlands)

Koopmans, LVE; Fassnacht, CD

1999-01-01

We present mass models of the four-image gravitational lens system B1608 + 656, based on information obtained through VLBA imaging, VLA monitoring, and Hubble Space Telescope (HST) WFPC2 and NICMOS imaging. We have determined a mass model for the lens galaxies that reproduces (1) all image positions

Polarization and brightness of the blazar S5 0716+714 in 1991-2004

Science.gov (United States)

Doroshenko, V. T.; Kiselev, N. N.

2017-06-01

We investigate the photometric and polarimetric behavior of the blazar S5 0716+714 based on the observations carried out in 1991-2004 at the 125-cm Crimean Astrophysical Observatory telescope (AZT11) with a photopolarimeter that allows simultaneous polarization and brightness measurements to be made in the U BV RI bands. We also provide the U BV photometry for the blazar obtained in 2000-2009 with a 60-cm telescope at the Crimean Station of the Sternberg Astronomical Institute. The pattern of flux variability and the correlation between the brightness, color, and polarization variations have been investigated. In this time interval the blazar showed a significant brightness and polarization variability similar to noise processes.

Full-Stokes polarimetry with circularly polarized feeds. Sources with stable linear and circular polarization in the GHz regime

Science.gov (United States)

Myserlis, I.; Angelakis, E.; Kraus, A.; Liontas, C. A.; Marchili, N.; Aller, M. F.; Aller, H. D.; Karamanavis, V.; Fuhrmann, L.; Krichbaum, T. P.; Zensus, J. A.

2018-01-01

We present an analysis pipeline that enables the recovery of reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the effective treatment of the instrumental effects even before the computation of the Stokes parameters, contrary to conventionally used methods such as that based on the Müller matrix. For instance, instrumental linear polarization is corrected across the whole telescope beam and significant Stokes Q and U can be recovered even when the recorded signals are severely corrupted by instrumental effects. The accuracy we reach in terms of polarization degree is of the order of 0.1-0.2%. The polarization angles are determined with an accuracy of almost 1°. The presented methodology was applied to recover the linear and circular polarization of around 150 active galactic nuclei, which were monitored between July 2010 and April 2016 with the Effelsberg 100-m telescope at 4.85 GHz and 8.35 GHz with a median cadence of 1.2 months. The polarized emission of the Moon was used to calibrate the polarization angle measurements. Our analysis showed a small system-induced rotation of about 1° at both observing frequencies. Over the examined period, five sources have significant and stable linear polarization; three sources remain constantly linearly unpolarized; and a total of 11 sources have stable circular polarization degree mc, four of them with non-zero mc. We also identify eight sources that maintain a stable polarization angle. All this is provided to the community for future polarization observations reference. We finally show that our analysis method is conceptually different from those traditionally used and performs better than the Müller matrix method. Although it has been developed for a system equipped with circularly polarized feeds, it can easily be generalized to systems with linearly polarized feeds as well. The data used to create Fig. C.1 are only available at the CDS via anonymous ftp to http

INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE

Energy Technology Data Exchange (ETDEWEB)

Deming, Drake; Wilkins, Ashlee [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); McCullough, Peter; Crouzet, Nicolas [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Agol, Eric; Dobbs-Dixon, Ian [NASA Astrobiology Institute' s Virtual Planetary Laboratory (United States); Madhusudhan, Nikku [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Desert, Jean-Michel; Knutson, Heather A.; Line, Michael [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Haynes, Korey [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Magic, Zazralt [Max-Planck-Institut fuer Astrophysik, D-85741 Garching (Germany); Mandell, Avi M.; Clampin, Mark [NASA' s Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ranjan, Sukrit; Charbonneau, David [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Seager, Sara, E-mail: ddeming@astro.umd.edu [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); and others

2013-09-10

Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scan mode. Our errors are within 6% (XO-1) and 26% (HD 209458b) of the photon-limit at a resolving power of {lambda}/{delta}{lambda} {approx} 70, and are better than 0.01% per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 {mu}m. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD 209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 cm{sup 2} g{sup -1} account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and/or dust. However, the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.

Polarization of the changing-look quasar J1011+5442

Science.gov (United States)

Hutsemékers, D.; Agís González, B.; Sluse, D.; Ramos Almeida, C.; Acosta Pulido, J.-A.

2017-07-01

If the disappearance of the broad emission lines observed in changing-look quasars were caused by the obscuration of the quasar core through moving dust clouds in the torus, high linear polarization typical of type 2 quasars would be expected. We measured the polarization of the changing-look quasar J1011+5442 in which the broad emission lines have disappeared between 2003 and 2015. We found a polarization degree compatible with null polarization. This measurement suggests that the observed change of look is not due to a change of obscuration hiding the continuum source and the broad line region, and that the quasar is seen close to the system axis. Our results thus support the idea that the vanishing of the broad emission lines in J1011+5442 is due to an intrinsic dimming of the ionizing continuum source that is most likely caused by a rapid decrease in the rate of accretion onto the supermassive black hole. Based on observations made with the William Herschel telescope operated on the island of La Palma by the Isaac Newton Group of Telescopes in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

The Simons Array: expanding POLARBEAR to three multi-chroic telescopes

Science.gov (United States)

Arnold, K.; Stebor, N.; Ade, P. A. R.; Akiba, Y.; Anthony, A. E.; Atlas, M.; Barron, D.; Bender, A.; Boettger, D.; Borrill, J.; Chapman, S.; Chinone, Y.; Cukierman, A.; Dobbs, M.; Elleflot, T.; Errard, J.; Fabbian, G.; Feng, C.; Gilbert, A.; Goeckner-Wald, N.; Halverson, N. W.; Hasegawa, M.; Hattori, K.; Hazumi, M.; Holzapfel, W. L.; Hori, Y.; Inoue, Y.; Jaehnig, G. C.; Jaffe, A. H.; Katayama, N.; Keating, B.; Kermish, Z.; Keskitalo, R.; Kisner, T.; Le Jeune, M.; Lee, A. T.; Leitch, E. M.; Linder, E.; Matsuda, F.; Matsumura, T.; Meng, X.; Miller, N. J.; Morii, H.; Myers, M. J.; Navaroli, M.; Nishino, H.; Okamura, T.; Paar, H.; Peloton, J.; Poletti, D.; Raum, C.; Rebeiz, G.; Reichardt, C. L.; Richards, P. L.; Ross, C.; Rotermund, K. M.; Schenck, D. E.; Sherwin, B. D.; Shirley, I.; Sholl, M.; Siritanasak, P.; Smecher, G.; Steinbach, B.; Stompor, R.; Suzuki, A.; Suzuki, J.; Takada, S.; Takakura, S.; Tomaru, T.; Wilson, B.; Yadav, A.; Zahn, O.

2014-08-01

The Simons Array is an expansion of the POLARBEAR cosmic microwave background (CMB) polarization experiment currently observing from the Atacama Desert in Northern Chile. This expansion will create an array of three 3.5m telescopes each coupled to a multichroic bolometric receiver. The Simons Array will have the sensitivity to produce a >= 5σ detection of inationary gravitational waves with a tensor-to-scalar ratio r >= 0:01, detect the known minimum 58 meV sum of the neutrino masses with 3σ confidence when combined with a next-generation baryon acoustic oscillation measurement, and make a lensing map of large-scale structure over the 80% of the sky available from its Chilean site. These goals require high sensitivity and the ability to extract the CMB signal from contaminating astrophysical foregrounds; these requirements are met by coupling the three high-throughput telescopes to novel multichroic lenslet-coupled pixels each measuring CMB photons in both linear polarization states over multiple spectral bands. We present the status of this instrument already under construction, and an analysis of its capabilities.

ARNICA, the Arcetri near-infrared camera: Astronomical performance assessment.

Science.gov (United States)

Hunt, L. K.; Lisi, F.; Testi, L.; Baffa, C.; Borelli, S.; Maiolino, R.; Moriondo, G.; Stanga, R. M.

1996-01-01

The Arcetri near-infrared camera ARNICA was built as a users' instrument for the Infrared Telescope at Gornergrat (TIRGO), and is based on a 256x256 NICMOS 3 detector. In this paper, we discuss ARNICA's optical and astronomical performance at the TIRGO and at the William Herschel Telescope on La Palma. Optical performance is evaluated in terms of plate scale, distortion, point spread function, and ghosting. Astronomical performance is characterized by camera efficiency, sensitivity, and spatial uniformity of the photometry.

Directional sensitivity of MuSTAnG muon telescope

Directory of Open Access Journals (Sweden)

Ganeva Marina

2013-04-01

Full Text Available We investigate directional sensitivity of MuSTAnG muon telescope by deriving the distribution of secondary muons, which create the counting rate of telescope, by asymptotic directions of primary protons. This distribution, defined as “directivity function”, allows us to clarify protons appearing from which direction essentially contribute to counting rate of detector. Directivity function has different behavior for the muons falling on the telescope at different zenith and polar angles. Vertical, West, and East fluxes exhibit strong maximums near the asymptotic longitude about 61°, whereas North and South fluxes have larger spread distributions. About 65% of muons, which create the Vertical counting rate of MuSTAnG, are produced by the primary protons, coming in the interval of asymptotic longitudes about (50°, 80°. Using directivity function will allow one to more correctly determine the location of interplanetary disturbances. Analogous analysis, made for other muon detectors, will clarify their directional sensitivities, improving by this the forecasting capability of network of ground-based muon detectors.

Optical Correction Of Space-Based Telescopes Using A Deformable Mirror System

Science.gov (United States)

2016-12-01

492 DM. The quarter wave plates polarize the light so that as it reflects off the DM, the light is then redirected at the beam splitter to the one...1  II.  SPACE-BASED TELESCOPE DESIGN CONSIDERATIONS .......................3  A.  ADAPTIVE OPTICS...3  B.  DESIGN CONSTRAINTS

Optimal strategy for polarization modulation in the LSPE-SWIPE experiment

Science.gov (United States)

Buzzelli, A.; de Bernardis, P.; Masi, S.; Vittorio, N.; de Gasperis, G.

2018-01-01

Context. Cosmic microwave background (CMB) B-mode experiments are required to control systematic effects with an unprecedented level of accuracy. Polarization modulation by a half wave plate (HWP) is a powerful technique able to mitigate a large number of the instrumental systematics. Aims: Our goal is to optimize the polarization modulation strategy of the upcoming LSPE-SWIPE balloon-borne experiment, devoted to the accurate measurement of CMB polarization at large angular scales. Methods: We departed from the nominal LSPE-SWIPE modulation strategy (HWP stepped every 60 s with a telescope scanning at around 12 deg/s) and performed a thorough investigation of a wide range of possible HWP schemes (either in stepped or continuously spinning mode and at different azimuth telescope scan-speeds) in the frequency, map and angular power spectrum domain. In addition, we probed the effect of high-pass and band-pass filters of the data stream and explored the HWP response in the minimal case of one detector for one operation day (critical for the single-detector calibration process). We finally tested the modulation performance against typical HWP-induced systematics. Results: Our analysis shows that some stepped HWP schemes, either slowly rotating or combined with slow telescope modulations, represent poor choices. Moreover, our results point out that the nominal configuration may not be the most convenient choice. While a large class of spinning designs provides comparable results in terms of pixel angle coverage, map-making residuals and BB power spectrum standard deviations with respect to the nominal strategy, we find that some specific configurations (e.g., a rapidly spinning HWP with a slow gondola modulation) allow a more efficient polarization recovery in more general real-case situations. Conclusions: Although our simulations are specific to the LSPE-SWIPE mission, the general outcomes of our analysis can be easily generalized to other CMB polarization experiments.

Time-resolved Polarimetry of the Superluminous SN 2015bn with the Nordic Optical Telescope

DEFF Research Database (Denmark)

Leloudas, Giorgos; Maund, Justyn R.; Gal-Yam, Avishay

2017-01-01

We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between -20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs of spectropol......We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between -20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs...... of spectropolarimetry are also available. Based on field stars, we determine the interstellar polarization in the Galaxy to be negligible. The polarization of SN 2015bn shows a statistically significant increase during the last epochs, confirming previous findings. Our well-sampled imaging polarimetry series allows us...

Liverpool Telescope and Liverpool Telescope 2

Science.gov (United States)

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

2016-12-01

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

Polarization observations of four southern pulsars at 1560 MHz

Science.gov (United States)

Wu, Xin-Ji; Manchester, R. N.; Lyne, A. G.

1991-12-01

Some interesting results from the mean pulse polarization observations of four southern pulsars made at the Australian National Radio Astronomy Observatory, Parkes, using the 64-m telescope in June and July, 1988, are presented. The 2 x 16 x 5 MHz filter system from Jodrell Bank has proved excellent in dedispersing the pulse signals and measuring their polarization properties. Data for the four pulsars are given in some detail, and their spectral behavior is discussed.

The Atacama Cosmology Telescope: two-season ACTPol spectra and parameters

Energy Technology Data Exchange (ETDEWEB)

Louis, Thibaut [UPMC Univ Paris 06, UMR7095, Institut d' Astrophysique de Paris, F-75014, Paris (France); Grace, Emily; Aiola, Simone; Choi, Steve K. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Hasselfield, Matthew [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Lungu, Marius; Angile, Elio [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Maurin, Loïc [Instituto de Astrofísica and Centro de Astro-Ingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile); Addison, Graeme E. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Ade, Peter A. R. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, Wales, CF24 3AA (United Kingdom); Allison, Rupert; Calabrese, Erminia [Sub-Department of Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Amiri, Mandana [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z4 (Canada); Battaglia, Nicholas [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Beall, James A.; Britton, Joe; Cho, Hsiao-mei [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); De Bernardis, Francesco [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Bond, J Richard, E-mail: louis@iap.fr [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON, M5S 3H8 (Canada); and others

2017-06-01

We present the temperature and polarization angular power spectra measured by the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time data collected during 2013–14 using two detector arrays at 149 GHz, from 548 deg{sup 2} of sky on the celestial equator. We use these spectra, and the spectra measured with the MBAC camera on ACT from 2008–10, in combination with planck and wmap data to estimate cosmological parameters from the temperature, polarization, and temperature-polarization cross-correlations. We find the new ACTPol data to be consistent with the ΛCDM model. The ACTPol temperature-polarization cross-spectrum now provides stronger constraints on multiple parameters than the ACTPol temperature spectrum, including the baryon density, the acoustic peak angular scale, and the derived Hubble constant. The new ACTPol data provide information on damping tail parameters. The joint uncertainty on the number of neutrino species and the primordial helium fraction is reduced by 20% when adding ACTPol to Planck temperature data alone.

The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and Parameters

Science.gov (United States)

Louis, Thibaut; Grace, Emily; Hasselfield, Matthew; Lungu, Marius; Maurin, Loic; Addison, Graeme E.; Adem Peter A. R.; Aiola, Simone; Allison, Rupert; Amiri, Mandana;

Optical modeling and polarization calibration for CMB measurements with ACTPol and Advanced ACTPol

Science.gov (United States)

Koopman, Brian; Austermann, Jason; Cho, Hsiao-Mei; Coughlin, Kevin P.; Duff, Shannon M.; Gallardo, Patricio A.; Hasselfield, Matthew; Henderson, Shawn W.; Ho, Shuay-Pwu Patty; Hubmayr, Johannes; Irwin, Kent D.; Li, Dale; McMahon, Jeff; Nati, Federico; Niemack, Michael D.; Newburgh, Laura; Page, Lyman A.; Salatino, Maria; Schillaci, Alessandro; Schmitt, Benjamin L.; Simon, Sara M.; Vavagiakis, Eve M.; Ward, Jonathan T.; Wollack, Edward J.

2016-07-01

The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive upgrade to the Atacama Cosmology Telescope, located at an elevation of 5190 m on Cerro Toco in Chile. ACTPol uses transition edge sensor bolometers coupled to orthomode transducers to measure both the temperature and polarization of the Cosmic Microwave Background (CMB). Calibration of the detector angles is a critical step in producing polarization maps of the CMB. Polarization angle offsets in the detector calibration can cause leakage in polarization from E to B modes and induce a spurious signal in the EB and TB cross correlations, which eliminates our ability to measure potential cosmological sources of EB and TB signals, such as cosmic birefringence. We calibrate the ACTPol detector angles by ray tracing the designed detector angle through the entire optical chain to determine the projection of each detector angle on the sky. The distribution of calibrated detector polarization angles are consistent with a global offset angle from zero when compared to the EB-nulling offset angle, the angle required to null the EB cross-correlation power spectrum. We present the optical modeling process. The detector angles can be cross checked through observations of known polarized sources, whether this be a galactic source or a laboratory reference standard. To cross check the ACTPol detector angles, we use a thin film polarization grid placed in front of the receiver of the telescope, between the receiver and the secondary reflector. Making use of a rapidly rotating half-wave plate (HWP) mount we spin the polarizing grid at a constant speed, polarizing and rotating the incoming atmospheric signal. The resulting sinusoidal signal is used to determine the detector angles. The optical modeling calibration was shown to be consistent with a global offset angle of zero when compared to EB nulling in the first ACTPol results and will continue to be a part of our calibration implementation. The first

Ghost telescope and ghost Fourier telescope with thermal light

International Nuclear Information System (INIS)

Gong Wenlin; Han Shensheng

2011-01-01

As important observation tools, telescopes are very useful in remote observations. We report a proof-of-principle experimental demonstration of ghost telescope scheme and show that, by measuring the intensity correlation of two light fields and only changing the position of the detector in the reference path, ghost telescope and ghost Fourier telescope can be obtained even if a single-pixel detector is fixed in Fresnel region of the object. Differences between conventional telescope and ghost telescope are also discussed.

Early optical polarization of a gamma-ray burst afterglow.

Science.gov (United States)

Mundell, Carole G; Steele, Iain A; Smith, Robert J; Kobayashi, Shiho; Melandri, Andrea; Guidorzi, Cristiano; Gomboc, Andreja; Mottram, Chris J; Clarke, David; Monfardini, Alessandro; Carter, David; Bersier, David

2007-03-30

We report the optical polarization of a gamma-ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma-rays from GRB 060418, using a ring polarimeter on the robotic Liverpool Telescope. Our robust (2sigma) upper limit on the percentage of polarization, less than 8%, coincides with the fireball deceleration time at the onset of the afterglow. The combination of the rate of decay of the optical brightness and the low polarization at this critical time constrains standard models of GRB ejecta, ruling out the presence of a large-scale ordered magnetic field in the emitting region.

Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

Science.gov (United States)

Harding, Alice K.

2012-01-01

Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. I will review acceleration and gamma-ray emission from the pulsar polar cap and slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting and population synthesis.

A balloon borne telescope for planetary observations with a fine pointing technology

Science.gov (United States)

Shoji, Yasuhiro; Onishi, Tomoya; Battazzo, Steve; Yoshimura, Atsushi; Sakamoto, Yuji; Yoshida, Kazuya; Takahashi, Yukihiro; Taguchi, Makoto

A balloon borne telescope is one of the effective observation methods for planets under space environment. A telescope is carried up to the stratosphere at an altitude of higher than 32 km where the air density is as thin as 1/100 of that at the ground. The thin atmosphere gives a telescope better observation conditions: fine seeing, stable weather, and high transmittance especially in the infrared region. Moreover there is a chance that a planet can be continuously seen for a window longer than 24 hours from the polar stratosphere. The authors have been developing a balloon borne telescope system for years to take finer images of planets in the solar system., The first object is Venus, of which atmospheric motions are derived by tracking the changes of cloud patterns with bands of UV, visible and NIR. Highly precise pointing control within the error of sub-arcseconds is required so that the balloon borne telescope achieves its diffraction-limited spatial resolution. The flight system is equipped with a three-stage attitude and pointing control system in order to realize the desired pointing control precision. In 2009, the flight system was built and tested in various ground tests and an actual balloon flight. Although the balloon experiment failed due to trouble with an onboard computer, the ground tests before the flight operation have verified that the pointing control system can achieve pointing error of less than 0.2 arcseconds. The balloon borne telescope is being redesigned for a sequential observation of Venus, Mars and Jupiter in the summer of 2011. This flight will be a step for a long-duration observation in the polar stratosphere. Additionally, an observation of the sodium tail of Mercury with a small telescope and a wide field of view has been under consideration. Mercury has very thin atmosphere called a surface-bounded exosphere. Past observations by spacecraft and ground-based telescopes revealed that one of the atmospheric components, gaseous

A Pair Production Telescope for Medium-Energy Gamma-Ray Polarimetry

Science.gov (United States)

Hunter, Stanley D.; Bloser, Peter F.; Depaola, Gerardo; Dion, Michael P.; DeNolfo, Georgia A.; Hanu, Andrei; Iparraguirre, Marcos; Legere, Jason; Longo, Francesco; McConnell, Mark L.;

ATST telescope mount: telescope of machine tool

Science.gov (United States)

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

2012-09-01

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

Prime focus architectures for large space telescopes: reduce surfaces to save cost

Science.gov (United States)

Breckinridge, J. B.; Lillie, C. F.

2016-07-01

Conceptual architectures are now being developed to identify future directions for post JWST large space telescope systems to operate in the UV Optical and near IR regions of the spectrum. Here we show that the cost of optical surfaces within large aperture telescope/instrument systems can exceed $100M/reflection when expressed in terms of the aperture increase needed to over come internal absorption loss. We recommend a program in innovative optical design to minimize the number of surfaces by considering multiple functions for mirrors. An example is given using the Rowland circle imaging spectrometer systems for UV space science. With few exceptions, current space telescope architectures are based on systems optimized for ground-based astronomy. Both HST and JWST are classical "Cassegrain" telescopes derived from the ground-based tradition to co-locate the massive primary mirror and the instruments at the same end of the metrology structure. This requirement derives from the dual need to minimize observatory dome size and cost in the presence of the Earth's 1-g gravitational field. Space telescopes, however function in the zero gravity of space and the 1- g constraint is relieved to the advantage of astronomers. Here we suggest that a prime focus large aperture telescope system in space may have potentially have higher transmittance, better pointing, improved thermal and structural control, less internal polarization and broader wavelength coverage than Cassegrain telescopes. An example is given showing how UV astronomy telescopes use single optical elements for multiple functions and therefore have a minimum number of reflections.

Cryogen-free dilution refrigerator for ACTPOL polarization- sensitive receiver

Science.gov (United States)

Shvarts, V.; Zhao, Z.; Devlin, M. J.; Klein, J.; Lungu, M.; Schmitt, B.; Thornton, R.

2014-12-01

We present a new cryogenic receiver for the Atacama Cosmology Telescope (ACT), a six-meter diameter off-axis Gregorian telescope located at an altitude of 5,200 meters (17,000 ft.) on Cerro Toco, in Northern Chile. The focal plane contains 3000 polarization-sensitive transition edge sensor (TES) bolometers, and is cooled to below 100 mK with a removable pulse-tube based customised JDry-100 dilution refrigerator insert. The optical tubes and the rest of the receiver are cooled with a dedicated pulse tube to below 3 K. Details of the receiver- to-telescope integration and first season on-site operation are described, including detector base temperature stability in vertical and tilted position as well as remote operation via Ethernet link.

Cryogen-free dilution refrigerator for ACTPOL polarization- sensitive receiver

International Nuclear Information System (INIS)

Shvarts, V; Zhao, Z; Devlin, M J; Klein, J; Lungu, M; Schmitt, B; Thornton, R

2014-01-01

We present a new cryogenic receiver for the Atacama Cosmology Telescope (ACT), a six-meter diameter off-axis Gregorian telescope located at an altitude of 5,200 meters (17,000 ft.) on Cerro Toco, in Northern Chile. The focal plane contains 3000 polarization-sensitive transition edge sensor (TES) bolometers, and is cooled to below 100 mK with a removable pulse-tube based customised JDry-100 dilution refrigerator insert. The optical tubes and the rest of the receiver are cooled with a dedicated pulse tube to below 3 K. Details of the receiver- to-telescope integration and first season on-site operation are described, including detector base temperature stability in vertical and tilted position as well as remote operation via Ethernet link

A Millimeter Polarimeter for the 45-m Telescope at Nobeyama

Science.gov (United States)

Shinnaga, Hiroko; Tsuboi, Masato; Kasuga, Takashi

1999-04-01

We have designed and constructed a tunable polarimeter to cover frequencies from 35 GHz to 250 GHz (8.6 mm and 1.2 mm in wavelength) for the 45-m telescope at Nobeyama Radio Observatory. Both circular and linear polarizations can be measured by the polarimeter. The insertion loss was measured to be 0.14 +/- 0.05 dB in the 100-GHz band. The overall instrumental polarization of the system in the 100 GHz band is as low as VY Canis Majoris. The observation revealed that the J = 2--1 emission in the v = 0 state of the object is highly linear polarized, which suggests that the emission originates through maser action in the circumstellar region. The details of the design, construction, and tests are presented. Nobeyama Radio Observatory is a branch of the National Astronomical Observatory, operated by the Ministry of Education, Science, Sports and Culture.

Far Sidelobe Effects from Panel Gaps of the Atacama Cosmology Telescope

Science.gov (United States)

Fluxa, Pedro R.; Duenner, Rolando; Maurin, Loiec; Choi, Steve K.; Devlin, Mark J.; Gallardo, Patricio A.; Shuay-Pwu, P. Ho; Koopman, Brian J.; Louis, Thibaut; Wollack, Edward J.

2016-01-01

The Atacama Cosmology Telescope is a 6 meter diameter CMB telescope located at 5200 meters in the Chilean desert. ACT has made arc-minute scale maps of the sky at 90 and 150 GHz which have led to precise measurements of the fine angular power spectrum of the CMB fluctuations in temperature and polarization. One of the goals of ACT is to search for the B-mode polarization signal from primordial gravity waves, and thus extending ACT's data analysis to larger angular scales. This goal introduces new challenges in the control of systematic effects, including better understanding of far sidelobe effects that might enter the power spectrum at degree angular scales. Here we study the effects of the gaps between panels of the ACT primary and secondary reflectors in the worst case scenario in which the gaps remain open. We produced numerical simulations of the optics using GRASP up to 8 degrees away from the main beam and simulated timestreams for observations with this beam using real pointing information from ACT data. Maps from these simulated timestreams showed leakage from the sidelobes, indicating that this effect must be taken into consideration at large angular scales.

THE STRUCTURES AND TOTAL (MINOR + MAJOR) MERGER HISTORIES OF MASSIVE GALAXIES UP TO z {approx} 3 IN THE HST GOODS NICMOS SURVEY: A POSSIBLE SOLUTION TO THE SIZE EVOLUTION PROBLEM

Energy Technology Data Exchange (ETDEWEB)

Bluck, Asa F. L. [Gemini Observatory, Northern Operations Center, Hilo, Hawaii 96720 (United States); Conselice, Christopher J.; Buitrago, Fernando; Gruetzbauch, Ruth; Hoyos, Carlos; Mortlock, Alice [Centre for Astronomy and Particle Theory, School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Bauer, Amanda E., E-mail: abluck@gemini.edu, E-mail: conselice@nottingham.ac.uk, E-mail: abauer@aa0.gov.au [Australian Astronomical Observatory, Epping, NSW 1710 (Australia)

2012-03-01

We investigate the total major (>1:4 by stellar mass) and minor (>1:100 by stellar mass) merger history of a population of 80 massive (M{sub *} > 10{sup 11} M{sub Sun }) galaxies at high redshifts (z = 1.7-3). We utilize extremely deep and high-resolution Hubble Space Telescope H-band imaging from the GOODS NICMOS Survey, which corresponds to rest-frame optical wavelengths at the redshifts probed. We find that massive galaxies at high redshifts are often morphologically disturbed, with a CAS (concentration, C; asymmetry, A; clumpiness, S) deduced merger fraction f{sub m} = 0.23 {+-} 0.05 at z = 1.7-3. We find close accord between close pair methods (within 30 kpc apertures) and CAS methods for deducing major merger fractions at all redshifts. We deduce the total (minor + major) merger history of massive galaxies with M{sub *} > 10{sup 9} M{sub Sun} galaxies, and find that this scales roughly linearly with log-stellar-mass and magnitude range. We test our close pair methods by utilizing mock galaxy catalogs from the Millennium Simulation. We compute the total number of mergers to be (4.5 {+-} 2.9)/({tau}{sub m}) from z = 3 to the present, to a stellar mass sensitivity threshold of {approx}1:100 (where {tau}{sub m} is the merger timescale in Gyr which varies as a function of mass). This corresponds to an average mass increase of (3.4 {+-} 2.2) Multiplication-Sign 10{sup 11} M{sub Sun} over the past 11.5 Gyr due to merging. We show that the size evolution observed for these galaxies may be mostly explained by this merging.

THE STRUCTURES AND TOTAL (MINOR + MAJOR) MERGER HISTORIES OF MASSIVE GALAXIES UP TO z ∼ 3 IN THE HST GOODS NICMOS SURVEY: A POSSIBLE SOLUTION TO THE SIZE EVOLUTION PROBLEM

International Nuclear Information System (INIS)

Bluck, Asa F. L.; Conselice, Christopher J.; Buitrago, Fernando; Grützbauch, Ruth; Hoyos, Carlos; Mortlock, Alice; Bauer, Amanda E.

2012-01-01

We investigate the total major (>1:4 by stellar mass) and minor (>1:100 by stellar mass) merger history of a population of 80 massive (M * > 10 11 M ☉ ) galaxies at high redshifts (z = 1.7-3). We utilize extremely deep and high-resolution Hubble Space Telescope H-band imaging from the GOODS NICMOS Survey, which corresponds to rest-frame optical wavelengths at the redshifts probed. We find that massive galaxies at high redshifts are often morphologically disturbed, with a CAS (concentration, C; asymmetry, A; clumpiness, S) deduced merger fraction f m = 0.23 ± 0.05 at z = 1.7-3. We find close accord between close pair methods (within 30 kpc apertures) and CAS methods for deducing major merger fractions at all redshifts. We deduce the total (minor + major) merger history of massive galaxies with M * > 10 9 M ☉ galaxies, and find that this scales roughly linearly with log-stellar-mass and magnitude range. We test our close pair methods by utilizing mock galaxy catalogs from the Millennium Simulation. We compute the total number of mergers to be (4.5 ± 2.9)/(τ m ) from z = 3 to the present, to a stellar mass sensitivity threshold of ∼1:100 (where τ m is the merger timescale in Gyr which varies as a function of mass). This corresponds to an average mass increase of (3.4 ± 2.2) × 10 11 M ☉ over the past 11.5 Gyr due to merging. We show that the size evolution observed for these galaxies may be mostly explained by this merging.

π--induced single charge exchange on polarized 3He

International Nuclear Information System (INIS)

Zhao, Q.; Burleson, S.; Blanchard, T.

1995-01-01

Asymmetries, A y , for the (π - ,π 0 ) reaction on polarized 3 He were measured using the pion beam of the P3W channel at LAMPF. The π 0 were detected with the new Neutral Meson Spectrometer (NMS) in coincidence with recoiling tritons. The recoil detector consisted of scintillation-counter telescopes and a wire chamber that provided energy-loss and direction information, respectively. The polarized gaseous 3 He target developed at TRIUMF was modified and run with the use of two diode lasers. Polarizations were typically 50%. The A y taken at T π = 200 MeV between 60 and 105 degrees were found to be strongly angle-dependent. The results will be compared with the theoretical predictions

A New Limit on CMB Circular Polarization from SPIDER

Science.gov (United States)

Nagy, J. M.; Ade, P. A. R.; Amiri, M.; Benton, S. J.; Bergman, A. S.; Bihary, R.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Doré, O.; Duivenvoorden, A. J.; Eriksen, H. K.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Freese, K.; Galloway, M.; Gambrel, A. E.; Gandilo, N. N.; Ganga, K.; Gudmundsson, J. E.; Halpern, M.; Hartley, J.; Hasselfield, M.; Hilton, G.; Holmes, W.; Hristov, V. V.; Huang, Z.; Irwin, K. D.; Jones, W. C.; Kuo, C. L.; Kermish, Z. D.; Li, S.; Mason, P. V.; Megerian, K.; Moncelsi, L.; Morford, T. A.; Netterfield, C. B.; Nolta, M.; Padilla, I. L.; Racine, B.; Rahlin, A. S.; Reintsema, C.; Ruhl, J. E.; Runyan, M. C.; Ruud, T. M.; Shariff, J. A.; Soler, J. D.; Song, X.; Trangsrud, A.; Tucker, C.; Tucker, R. S.; Turner, A. D.; Van Der List, J. F.; Weber, A. C.; Wehus, I. K.; Wiebe, D. V.; Young, E. Y.

2017-08-01

We present a new upper limit on cosmic microwave background (CMB) circular polarization from the 2015 flight of Spider, a balloon-borne telescope designed to search for B-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the nonzero circular-to-linear polarization coupling of the half-wave plate polarization modulators, data from Spider's 2015 Antarctic flight provide a constraint on Stokes V at 95 and 150 GHz in the range 33< {\\ell }< 307. No other limits exist over this full range of angular scales, and Spider improves on the previous limit by several orders of magnitude, providing 95% C.L. constraints on {\\ell }({\\ell }+1){C}{\\ell }{VV}/(2π ) ranging from 141 to 255 μK2 at 150 GHz for a thermal CMB spectrum. As linear CMB polarization experiments become increasingly sensitive, the techniques described in this paper can be applied to obtain even stronger constraints on circular polarization.

A New Limit on CMB Circular Polarization from SPIDER

Energy Technology Data Exchange (ETDEWEB)

Nagy, J. M.; Ade, P. A. R.; Amiri, M.; Benton, S. J.; Bergman, A. S.; Bihary, R.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Doré, O.; Duivenvoorden, A. J.; Eriksen, H. K.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Freese, K.; Galloway, M.; Gambrel, A. E.; Gandilo, N. N.; Ganga, K.; Gudmundsson, J. E.; Halpern, M.; Hartley, J.; Hasselfield, M.; Hilton, G.; Holmes, W.; Hristov, V. V.; Huang, Z.; Irwin, K. D.; Jones, W. C.; Kuo, C. L.; Kermish, Z. D.; Li, S.; Mason, P. V.; Megerian, K.; Moncelsi, L.; Morford, T. A.; Netterfield, C. B.; Nolta, M.; Padilla, I. L.; Racine, B.; Rahlin, A. S.; Reintsema, C.; Ruhl, J. E.; Runyan, M. C.; Ruud, T. M.; Shariff, J. A.; Soler, J. D.; Song, X.; Trangsrud, A.; Tucker, C.; Tucker, R. S.; Turner, A. D.; List, J. F. Van Der; Weber, A. C.; Wehus, I. K.; Wiebe, D. V.; Young, E. Y.

2017-08-01

We present a new upper limit on CMB circular polarization from the 2015 flight of SPIDER, a balloon-borne telescope designed to search for $B$-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the non-zero circular-to-linear polarization coupling of the HWP polarization modulators, data from SPIDER's 2015 Antarctic flight provides a constraint on Stokes $V$ at 95 and 150 GHz from $33<\\ell<307$. No other limits exist over this full range of angular scales, and SPIDER improves upon the previous limit by several orders of magnitude, providing 95% C.L. constraints on $\\ell (\\ell+1)C_{\\ell}^{VV}/(2\\pi)$ ranging from 141 $\\mu K ^2$ to 203 $\\mu K ^2$ at 150 GHz for a thermal CMB spectrum. As linear CMB polarization experiments become increasingly sensitive, the techniques described in this paper can be applied to obtain stronger constraints on circular polarization.

Development of the Advanced Energetic Pair Telescope (AdEPT) for Medium-Energy Gamma-Ray Astronomy

Science.gov (United States)

Hunter, Stanley D.; Bloser, Peter F.; Dion, Michael P.; McConnell, Mark L.; deNolfo, Georgia A.; Son, Seunghee; Ryan, James M.; Stecker, Floyd W.

2011-01-01

Progress in high-energy gamma-ray science has been dramatic since the launch of INTEGRAL, AGILE and FERMI. These instruments, however, are not optimized for observations in the medium-energy (approx.0.3< E(sub gamma)< approx.200 MeV) regime where many astrophysical objects exhibit unique, transitory behavior, such as spectral breaks, bursts, and flares. We outline some of the major science goals of a medium-energy mission. These science goals are best achieved with a combination of two telescopes, a Compton telescope and a pair telescope, optimized to provide significant improvements in angular resolution and sensitivity. In this paper we describe the design of the Advanced Energetic Pair Telescope (AdEPT) based on the Three-Dimensional Track Imager (3-DTI) detector. This technology achieves excellent, medium-energy sensitivity, angular resolution near the kinematic limit, and gamma-ray polarization sensitivity, by high resolution 3-D electron tracking. We describe the performance of a 30x30x30 cm3 prototype of the AdEPT instrument.

Using modern imaging techniques to old HST data: a summary of the ALICE program.

Science.gov (United States)

Choquet, Elodie; Soummer, Remi; Perrin, Marshall; Pueyo, Laurent; Hagan, James Brendan; Zimmerman, Neil; Debes, John Henry; Schneider, Glenn; Ren, Bin; Milli, Julien; Wolff, Schuyler; Stark, Chris; Mawet, Dimitri; Golimowski, David A.; Hines, Dean C.; Roberge, Aki; Serabyn, Eugene

2018-01-01

Direct imaging of extrasolar systems is a powerful technique to study the physical properties of exoplanetary systems and understand their formation and evolution mechanisms. The detection and characterization of these objects are challenged by their high contrast with their host star. Several observing strategies and post-processing algorithms have been developed for ground-based high-contrast imaging instruments, enabling the discovery of directly-imaged and spectrally-characterized exoplanets. The Hubble Space Telescope (HST), pioneer in directly imaging extrasolar systems, has yet been often limited to the detection of bright debris disks systems, with sensitivity limited by the difficulty to implement an optimal PSF subtraction stategy, which is readily offered on ground-based telescopes in pupil tracking mode.The Archival Legacy Investigations of Circumstellar Environments (ALICE) program is a consistent re-analysis of the 10 year old coronagraphic archive of HST's NICMOS infrared imager. Using post-processing methods developed for ground-based observations, we used the whole archive to calibrate PSF temporal variations and improve NICMOS's detection limits. We have now delivered ALICE-reprocessed science products for the whole NICMOS archival data back to the community. These science products, as well as the ALICE pipeline, were used to prototype the JWST coronagraphic data and reduction pipeline. The ALICE program has enabled the detection of 10 faint debris disk systems never imaged before in the near-infrared and several substellar companion candidates, which we are all in the process of characterizing through follow-up observations with both ground-based facilities and HST-STIS coronagraphy. In this publication, we provide a summary of the results of the ALICE program, advertise its science products and discuss the prospects of the program.

Testing of polarimeter UVP layout on telescope AZT-2

Science.gov (United States)

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

2018-05-01

Layout of on-board small-sized ultraviolet polarimeter was created. On its basis a ground version of the layout was prepared. It was installed on the AZT-2 telescope for carrying out special tests. With this device we investigated the possibility of determining the degree of polarization of the twilight glow of the Earth's atmosphere, and also worked out the observation methodology required for such work, and the basic principles of the implementation of this method. For this purpose, a special complex of auxiliary equipment was developed.

CONTEMPORANEOUS VLBA 5 GHz OBSERVATIONS OF LARGE AREA TELESCOPE DETECTED BLAZARS

Energy Technology Data Exchange (ETDEWEB)

Linford, J. D.; Taylor, G. B. [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131-0001 (United States); Romani, R. W. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Helmboldt, J. F. [Naval Research Laboratory, Code 7213, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Readhead, A. C. S.; Reeves, R.; Richards, J. L. [Astronomy Department, California Institute of Technology, Mail Code 247-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2012-01-10

The radio properties of blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA). In total, 232 sources were observed with the VLBA. Ninety sources that were previously observed as part of the VLBA Imaging and Polarimetry Survey (VIPS) have been included in the sample, as well as 142 sources not found in VIPS. This very large, 5 GHz flux-limited sample of active galactic nuclei (AGNs) provides insights into the mechanism that produces strong {gamma}-ray emission. In particular, we see that {gamma}-ray emission is related to strong, uniform magnetic fields in the cores of the host AGN. Included in this sample are non-blazar AGNs such as 3C84, M82, and NGC 6251. For the blazars, the total VLBA radio flux density at 5 GHz correlates strongly with {gamma}-ray flux. The LAT BL Lac objects tend to be similar to the non-LAT BL Lac objects, but the LAT flat-spectrum radio quasars (FSRQs) are significantly different from the non-LAT FSRQs. Strong core polarization is significantly more common among the LAT sources, and core fractional polarization appears to increase during LAT detection.

CONTEMPORANEOUS VLBA 5 GHz OBSERVATIONS OF LARGE AREA TELESCOPE DETECTED BLAZARS

International Nuclear Information System (INIS)

Linford, J. D.; Taylor, G. B.; Romani, R. W.; Helmboldt, J. F.; Readhead, A. C. S.; Reeves, R.; Richards, J. L.

2012-01-01

The radio properties of blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA). In total, 232 sources were observed with the VLBA. Ninety sources that were previously observed as part of the VLBA Imaging and Polarimetry Survey (VIPS) have been included in the sample, as well as 142 sources not found in VIPS. This very large, 5 GHz flux-limited sample of active galactic nuclei (AGNs) provides insights into the mechanism that produces strong γ-ray emission. In particular, we see that γ-ray emission is related to strong, uniform magnetic fields in the cores of the host AGN. Included in this sample are non-blazar AGNs such as 3C84, M82, and NGC 6251. For the blazars, the total VLBA radio flux density at 5 GHz correlates strongly with γ-ray flux. The LAT BL Lac objects tend to be similar to the non-LAT BL Lac objects, but the LAT flat-spectrum radio quasars (FSRQs) are significantly different from the non-LAT FSRQs. Strong core polarization is significantly more common among the LAT sources, and core fractional polarization appears to increase during LAT detection.

Contemporaneous VLBA 5 GHz Observations of Large Area Telescope Detected Blazars

Science.gov (United States)

Linford, J. D.; Taylor, G. B.; Romani, R. W.; Helmboldt, J. F.; Readhead, A. C. S.; Reeves, R.; Richards, J. L.

2012-01-01

The radio properties of blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA). In total, 232 sources were observed with the VLBA. Ninety sources that were previously observed as part of the VLBA Imaging and Polarimetry Survey (VIPS) have been included in the sample, as well as 142 sources not found in VIPS. This very large, 5 GHz flux-limited sample of active galactic nuclei (AGNs) provides insights into the mechanism that produces strong γ-ray emission. In particular, we see that γ-ray emission is related to strong, uniform magnetic fields in the cores of the host AGN. Included in this sample are non-blazar AGNs such as 3C84, M82, and NGC 6251. For the blazars, the total VLBA radio flux density at 5 GHz correlates strongly with γ-ray flux. The LAT BL Lac objects tend to be similar to the non-LAT BL Lac objects, but the LAT flat-spectrum radio quasars (FSRQs) are significantly different from the non-LAT FSRQs. Strong core polarization is significantly more common among the LAT sources, and core fractional polarization appears to increase during LAT detection.

ipole: Semianalytic scheme for relativistic polarized radiative transport

Science.gov (United States)

Moscibrodzka, Monika; Gammie, Charles F.

2018-04-01

ipole is a ray-tracing code for covariant, polarized radiative transport particularly useful for modeling Event Horizon Telescope sources, though may also be used for other relativistic transport problems. The code extends the ibothros scheme for covariant, unpolarized transport using two representations of the polarized radiation field: in the coordinate frame, it parallel transports the coherency tensor, and in the frame of the plasma, it evolves the Stokes parameters under emission, absorption, and Faraday conversion. The transport step is as spacetime- and coordinate- independent as possible; the emission, absorption, and Faraday conversion step is implemented using an analytic solution to the polarized transport equation with constant coefficients. As a result, ipole is stable, efficient, and produces a physically reasonable solution even for a step with high optical depth and Faraday depth.

The Polatron: A Millimeter-Wave Cosmic Microwave Background Polarimeter for the OVRO 5.5 m Telescope

OpenAIRE

Philhour, B. J.; Keating, B. G.; Ade, P. A. R.; Bhatia, R. S.; Bock, J. J.; Church, S. E.; Glenn, J.; Hinderks, J. R.; Hristov, V. V.; Jones, W. C.; Kamionkowski, M.; Kumar, D. E.; Lange, A. E.; Leong, J. R.; Marrone, D. P.

2001-01-01

We describe the development of a bolometric receiver designed to measure the arcminute-scale polarization of the cosmic microwave background (CMB). The Polatron will be mounted at the Cassegrain focus of the 5.5 m telescope at the Owens Valley Radio Observatory (OVRO). The receiver will measure both the Q and U Stokes parameters over a 20% pass-band centered near 100 GHz, with the input polarization signal modulated at ~0.6 Hz by a rotating, birefringent, quartz half-wave plate. In six months...

Direct Detection of Polarized, Scattered Light from Exoplanets

Science.gov (United States)

Laughlin, Gregory

We propose to radically advance the state of exoplanet characterization, which lags dramatically behind exoplanet discovery. We propose to directly detect scattered light from the atmospheres of close-in, highly eccentric, and extended/non-spherical exoplanets and thereby determine the following: orbital inclination (and therefore masses free of the M sin i mass ambiguity), geometric albedo, presence or lack of hazes and cloud layers, and scattering particle size and composition. Such measurements are crucial to the understanding of exoplanet atmospheres, because observations with NASA s Hubble, Spitzer, and Kepler space telescopes present the following questions: 1) Do exoplanets have highly reflective haze layers? 2) How does the upper atmospheric composition differ between exoplanets with and without thermal inversions? 3) What are the optical manifestations of the extreme heating of highly eccentric exoplanets? 4) Are the atmospheres of certain exoplanets truly escaping their Roche lobes? Using the POLISH2 polarimeter developed by the Postdoctoral Associate (Wiktorowicz) for the Lick 3-m telescope, we propose to monitor the linear polarization state of exoplanet host stars at the part per million level. POLISH2 consistently delivers nearly photon shot noise limited measurements with this precision. In addition, the simultaneous full-Stokes measurements of POLISH2 and the equatorial mount of the Lick 3-m telescope ensure that systematic effects are mitigated to the part per million level. Indeed, we find the accuracy of the POLISH2 polarimeter to be 0.1 parts per million. This instrument and telescope represent the highest precision polarimeter in the world for exoplanet research. We present potential detection of polarized, scattered light from the HD 189733b, Tau Boo b, and WASP-12b exoplanets. We propose to observe hot Jupiters on circular orbits, highly eccentric exoplanets, exoplanets with extended or non-spherical scattering surfaces, and 55 Cnc e, the

Polarized Gamma-Ray Emission from the Galactic Black Hole Cygnus X-1

Science.gov (United States)

Laurent, P.; Rodriquez, J.; Wilms, J.; Bel, M. Cadolle; Pottschmidt, K.; Grinberg, V.

2011-01-01

Because of their inherently high flux allowing the detection of clear signals, black hole X-ray binaries are interesting candidates for polarization studies, even if no polarization signals have been observed from them before. Such measurements would provide further detailed insight into these sources' emission mechanisms. We measured the polarization of the gamma-ray emission from the black hole binary system Cygnus X-I with the INTEGRAL/IBIS telescope. Spectral modeling ofthe data reveals two emission mechanisms: The 250-400 keY data are consistent with emission dominated by Compton scattering on thermal electrons and are weakly polarized. The second spectral component seen in the 400keV-2MeV band is by contrast strongly polarized, revealing that the MeV emission is probably related to the jet first detected in the radio band.

SUBMILLIMETER POLARIZATION SPECTRUM IN THE VELA C MOLECULAR CLOUD

Energy Technology Data Exchange (ETDEWEB)

Gandilo, Natalie N. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street Toronto, ON M5S 3H4 (Canada); Ade, Peter A. R.; Pascale, Enzo [Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom); Angilè, Francesco E.; Devlin, Mark J.; Dober, Bradley; Galitzki, Nicholas; Klein, Jeffrey [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA, 19104 (United States); Ashton, Peter; Fissel, Laura M.; Matthews, Tristan G.; Novak, Giles [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Benton, Steven J. [Department of Physics, Princeton University, Jadwin Hall, Princeton, NJ 08544 (United States); Fukui, Yasuo [Department of Physics and Astrophysics, Nagoya University, Nagoya 464-8602 (Japan); Korotkov, Andrei L. [Department of Physics, Brown University, 182 Hope Street, Providence, RI, 02912 (United States); Li, Zhi-Yun [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Martin, Peter G. [CITA, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Moncelsi, Lorenzo [California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA, 91125 (United States); Nakamura, Fumitaka [National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Netterfield, Calvin B., E-mail: ngandil1@jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, 3701 San Martin Drive, Baltimore, Maryland (United States); and others

2016-06-20

Polarization maps of the Vela C molecular cloud were obtained at 250, 350, and 500 μ m during the 2012 flight of the balloon-borne telescope BLASTPol. These measurements are used in conjunction with 850 μ m data from Planck to study the submillimeter spectrum of the polarization fraction for this cloud. The spectrum is relatively flat and does not exhibit a pronounced minimum at λ ∼ 350 μ m as suggested by previous measurements of other molecular clouds. The shape of the spectrum does not depend strongly on the radiative environment of the dust, as quantified by the column density or the dust temperature obtained from Herschel data. The polarization ratios observed in Vela C are consistent with a model of a porous clumpy molecular cloud being uniformly heated by the interstellar radiation field.

SHOES-Supernovae, HO, for the Equation of State of Dark energy

Science.gov (United States)

Riess, Adam

2006-07-01

The present uncertainty in the value of the Hubble constant {resulting in anuncertainty in Omega_M} and the paucity of Type Ia supernovae at redshiftsexceeding 1 are now the leading obstacles to determining the nature of darkenergy. We propose a single, integrated set of observations for Cycle 15 thatwill provide a 40% improvement in constraints on dark energy. This programwill observe known Cepheids in six reliable hosts of Type Ia supernovae withNICMOS, reducing the uncertainty in H_0 by a factor of two because of thesmaller dispersion along the instability strip, the diminished extinction, andthe weaker metallicity dependence in the infrared. In parallel with ACS, atthe same time the NICMOS observations are underway, we will discover andfollow a sample of Type Ia supernovae at z > 1. Together, these measurements,along with prior constraints from WMAP, will provide a great improvement inHST's ability to distinguish between a static, cosmological constant anddynamical dark energy. The Hubble Space Telescope is the only instrument inthe world that can make these IR measurements of Cepheids beyond the LocalGroup, and it is the only telescope in the world that can be used to find andfollow supernovae at z > 1. Our program exploits both of these uniquecapabilities of HST to learn more about one of the greatest mysteries inscience.

Observing the Sun with Coronado telescopes telescopes

CERN Document Server

Pugh, Philip

2007-01-01

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

Ultraviolet spectropolarimetry of high-redshift quasars with the Hubble Space Telescope

Science.gov (United States)

Impey, C. D.; Malkan, Matthew A.; Webb, Wayne; Petry, C. E.

1995-01-01

Ultraviolet spectropolarimetry of three bright high-redshift low-polarization quasars (LPQs) was obtained with the Faint Object Spectrograph of the Hubble Space Telescope (HST). Two of the quasars, PG 1634+706 and PG 2302+029, had polarizations p approximately = 0.5%-1.0% throughout the ultraviolet, and showed no significant variation of polarization amplitude or position angle with wavelength. PG 2302+029 was also marginally (2.4 sigma) circularly polarized in the optical continuum. For the highest redshift quasar, PG 1222+228 (Ton 1530), the polarization was measured down to rest wavelengths below 800 A. Although the continuum of PG 1222+228 was weakened by Lyman limit absorption from an intergalactic gas cloud, the polarization increased sharply from 1% to about 4.5%, a change of 4 sigma significance. This abrupt rise in polarization does not appear attributable to any known instrumental artifact. These UV polarizations were only slightly less than those previously observed for these same objects in the optical. The polarization spectra were flat with a typical slope of the polarized flux pF(sub nu) proportional to nu(exp -0.8 +/- 0.5). Unlike the case of several high luminosity Seyfert 1 nuclei studied previously, polarization caused by scattering from dust grains does not provide the best fit to the polarization spectra of these luminous quasars. These observed spectra are consistent with a wavelength-independent polarization proportional to the total nonstellar light or, possibly, to the contribution of the blue thermal component. The polarization spectra have insufficient signal-to-noise to locate the scatterers with respect to the continuum source and the much larger broad line region. A decrease in amplitude and rotation of the position angle of the polarization vector at the shortest wavelengths, which could result from general relativistic effects near a spinning black hole, was not observed. In fact, in PG 1222+228, the polarization was observed to

Development and calibration of the tracking Compton/Pair telescope MEGA

International Nuclear Information System (INIS)

Kanbach, G.; Andritschke, R.; Zoglauer, A.; Ajello, M.; McConnell, M.L.; Macri, J.R.; Ryan, J.M.; Bloser, P.; Hunter, S.; DiCocco, G.; Kurfess, J.; Reglero, V.

2005-01-01

We describe the development and tests of the prototype for a new telescope for Medium Energy Gamma-ray Astronomy (MEGA) in the energy band 0.4-50 MeV. As a successor to COMPTEL and EGRET (at low energies), MEGA aims to improve the sensitivity for astronomical sources by at least an order of magnitude. It could thus fill the severe sensitivity gap between scheduled or operating hard-X-ray and high-energy gamma-ray missions and open the way for a future Advanced Compton Telescope. MEGA records and images γ-rays by completely tracking Compton and Pair creation events in a stack of double-sided Si-strip track detectors surrounded by a pixelated CsI calorimeter. A scaled down prototype has been built and we describe technical details of its design and properties. Results from calibrations using radioactive sources and from measurements with an accelerator generated, fully polarized, γ-ray beam are presented and an outlook to future plans with MEGA is given

Single-Dish Radio Polarimetry in the F-GAMMA Program with the Effelsberg 100-m Radio Telescope

Directory of Open Access Journals (Sweden)

Beuchert Tobias

2013-12-01

Full Text Available Studying the variability of polarized AGN jet emission in the radio band is crucial for understanding the dynamics of moving shocks as well as the structure of the underlying magnetic field. The 100-m Effelsberg Telescope is a high-quality instrument for studying the long-term variability of both total and polarized intensity as well as the electric-vector position angle. Since 2007, the F-GAMMA program has been monitoring the linear polarized emission of roughly 60 blazars at 11 frequencies between 2.7 and 43 GHz. Here, we describe the calibration of the polarimetric data at 5 and 10 GHz and the resulting F-GAMMA full-Stokes light curves for the exemplary case of the radio galaxy 3C 111.

Preliminary optical design of polarization splitter box for ITER ECE diagnostic system

International Nuclear Information System (INIS)

Kumar, Ravinder; Danani, Suman; Pandya, Hitesh Kumar; Kumar, Vinay

2015-01-01

In tokamak, electron cyclotron emission (ECE) leaves the magnetically confined plasma with two polarizing modes, one with electric field parallel to magnetic field known as ordinary mode or O-Mode polarization, and other with the electric field perpendicular to magnetic field, extraordinary Mode or X-Mode. These radiation modes will be collected simultaneously in the ITER ECE measurement line. Therefore, it is necessary to split the radiation into O and X-mode polarizations before transmission otherwise there might be polarization mixing during transmission of the ECE radiation from tokamak to the measurement instruments. Proposed design of the polarization splitter box consists of two Gaussian beam telescopes built from three ellipsoidal mirrors and one flat mirror. A wire grid beam splitter separates the O and X-Mode polarization emission. The box is covered with microwave absorber to minimize scattering of the radiation. The design is being optimized by simulation using the Gaussian beam Mode software to achieve the desired performance, details will be discussed

Radio Telescope Focal Container for the Russian VLBI Network of New Generation

Science.gov (United States)

Ipatov, Alexander; Mardyshkin, Vyacheslav; Cherepanov, Andrey; Chernov, Vitaly; Diky, Dmitry; Khvostov, Evgeny; Yevstigneyev, Alexander

2010-01-01

This article considers the development of the structure of receivers for Russian radio telescopes. The development of these radio telescopes is undertaken within the project for creating a Russian small-antenna-based radio interferometer of new generation. It is shown that for small antennas (10. 12 meter) the principal unit, which provides the best SNR, is the so-called focal container placed at primary focus. It includes the primary feed, HEMT LNA, and cryogenic cooling system down to 20. K. A new multi-band feed based on traveling wave resonators is used. It has small dimensions, low weight, and allows working with circular polarizations. Thus it can be placed into focal container and cooled with the LNA. A sketch of the focal container, with traveling-wave-resonator feed, and calculations of the expected parameters of the multi-band receiver are presented.

Optical characterization and polarization calibration for rigid endoscopes

Science.gov (United States)

Garcia, Missael; Gruev, Viktor

2017-02-01

Polarization measurements give orthogonal information to spectral images making them a great tool in the characterization of environmental parameters in nature. Thus, polarization imagery has proven to be remarkably useful in a vast range of biomedical applications. One such application is the early diagnosis of flat cancerous lesions in murine colorectal tumor models, where polarization data complements NIR fluorescence analysis. Advances in nanotechnology have led to compact and precise bio-inspired imaging sensors capable of accurately co-registering multidimensional spectral and polarization information. As more applications emerge for these imagers, the optics used in these instruments get very complex and can potentially compromise the original polarization state of the incident light. Here we present a complete optical and polarization characterization of three rigid endoscopes of size 1.9mm x 10cm (Karl Storz, Germany), 5mm x 30cm, and 10mm x 33cm (Olympus, Germany), used in colonoscopy for the prevention of colitis-associated cancer. Characterization results show that the telescope optics act as retarders and effectively depolarize the linear component. These incorrect readings can cause false-positives or false-negatives leading to an improper diagnosis. In this paper, we offer a polarization calibration scheme for these endoscopes based on Mueller calculus. By modeling the optical properties from training data as real-valued Mueller matrices, we are able to successfully reconstruct the initial polarization state acquired by the imaging system.

The polarization of the decimeter radiation and the magnetic field of jupiter

International Nuclear Information System (INIS)

Neidhoefer, J.

1977-01-01

In the frame of polarization measurements with the newly developed Double-Channel-Korrelation-System, there were measurements conducted of the decimeter radiation of Jupiter at wavelengths of 11 and 18cm with the 100m telescope of the MPIFR. The operating mode, the construction, influences of errors and their elimination during operation described in such a receiving system. The most important particular components are investigated including their limits of performance. Measurement of antenna properties of the Effelsberg-telescope are presented at three wavelengths (18, 11 and 3.3 cm) including high-sensitivity antenna diagrams for all Stokes-parameter. (orig./WL) [de

FRONT-END ASIC FOR A SILICON COMPTON TELESCOPE.

Energy Technology Data Exchange (ETDEWEB)

DE GERONIMO,G.; FRIED, J.; FROST, E.; PHLIPS, B.; VERNON, E.; WULF, E.A.

2007-10-27

We describe a front-end application specific integrated circuit (ASIC) developed for a silicon Compton telescope. Composed of 32 channels, it reads out signals in both polarities from each side of a Silicon strip sensor, 2 mm thick 27 cm long, characterized by a strip capacitance of 30 pF. Each front-end channel provides low-noise charge amplification, shaping with a stabilized baseline, discrimination, and peak detection with an analog memory. The channels can process events simultaneously, and the read out is sparsified. The charge amplifier makes uses a dual-cascode configuration and dual-polarity adaptive reset, The low-hysteresis discriminator and the multi-phase peak detector process signals with a dynamic range in excess of four hundred. An equivalent noise charge (ENC) below 200 electrons was measured at 30 pF, with a slope of about 4.5 electrons/pF at a peaking time of 4 {micro}s. With a total dissipated power of 5 mW the channel covers an energy range up to 3.2 MeV.

The impact of Faraday effects on polarized black hole images of Sagittarius A*.

Science.gov (United States)

Jiménez-Rosales, Alejandra; Dexter, Jason

2018-05-01

We study model images and polarization maps of Sagittarius A* at 230 GHz. We post-process GRMHD simulations and perform a fully relativistic radiative transfer calculation of the emitted synchrotron radiation to obtain polarized images for a range of mass accretion rates and electron temperatures. At low accretion rates, the polarization map traces the underlying toroidal magnetic field geometry. At high accretion rates, we find that Faraday rotation internal to the emission region can depolarize and scramble the map. We measure the net linear polarization fraction and find that high accretion rate "jet-disc" models are heavily depolarized and are therefore disfavoured. We show how Event Horizon Telescope measurements of the polarized "correlation length" over the image provide a model-independent upper limit on the strength of these Faraday effects, and constrain plasma properties like the electron temperature and magnetic field strength.

Highly polarized emission from the E-hotspot in DA240

International Nuclear Information System (INIS)

Tsien, S.C.; Saunders, R.

1982-01-01

The hotspot in the eastern lobe of the nearby giant radio galaxy DA240 (z=0.0356) provides a rare opportunity to examine the detailed polarization structure of a hotspot. Maps have been made with the Cambridge 5-km telescope at 2.7 and 5.0 GHz and the 5.0-GHz maps are shown here. The main characteristics are discussed briefly. (Auth.)

The DAG project, a 4m class telescope: the telescope main structure performances

Science.gov (United States)

Marchiori, G.; Busatta, A.; Ghedin, L.; Marcuzzi, E.; Manfrin, C.; Battistel, C.; Pirnay, O.; Flebus, Carlo; Yeşilyaprak, C.; Keskin, O.; Yerli, S.

2016-07-01

Dogu Anatolu Gözlemevi (DAG-Eastern Anatolia Observatory) Project is a 4m class optical, near-infrared Telescope and suitable enclosure which will be located at an altitude of 3.170m in Erzurum, Turkey. The DAG telescope is a project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope - ATASAM. The Project is being developed by the Belgian company AMOS (project leader), which is also the optics supplier and EIE GROUP, the Telescope Main Structure supplier and responsible for the final site integration. The design of the Telescope Main Structure fits in the EIE TBO Program which aims at developing a Dome/Telescope systemic optimization process for both performances and competitive costs based on previous project commitments like NTT, VLT, VST and ASTRI. The optical Configuration of the DAG Telescope is a Ritchey-Chretien with two Nasmyth foci and a 4m primary thin mirror controlled in shape and position by an Active Optic System. The main characteristics of the Telescope Main Structure are an Altitude-Azimuth light and rigid structure system with Direct Drive Systems for both axis, AZ Hydrostatic Bearing System and Altitude standard bearing system; both axes are equipped with Tape Encoder System. An innovative Control System characterizes the telescope performance.

Polar ring galaxies in the Galaxy Zoo

Science.gov (United States)

Finkelman, Ido; Funes, José G.; Brosch, Noah

2012-05-01

We report observations of 16 candidate polar-ring galaxies (PRGs) identified by the Galaxy Zoo project in the Sloan Digital Sky Survey (SDSS) data base. Deep images of five galaxies are available in the SDSS Stripe82 data base, while to reach similar depth we observed the remaining galaxies with the 1.8-m Vatican Advanced Technology Telescope. We derive integrated magnitudes and u-r colours for the host and ring components and show continuum-subtracted Hα+[N II] images for seven objects. We present a basic morphological and environmental analysis of the galaxies and discuss their properties in comparison with other types of early-type galaxies. Follow-up photometric and spectroscopic observations will allow a kinematic confirmation of the nature of these systems and a more detailed analysis of their stellar populations.

ANTI-CORRELATED OPTICAL FLUX AND POLARIZATION VARIABILITY IN BL LAC

Energy Technology Data Exchange (ETDEWEB)

Gaur, Haritma [Inter-University Centre for Astronomy and Astrophysics (IUCAA), Ganeshkhind, Pune 411 007 (India); Gupta, Alok C. [Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital 263 129 (India); Wiita, Paul J. [Department of Physics, The College of New Jersey, P.O. Box 7718, Ewing, NJ 08628-0718 (United States); Uemura, Makoto; Itoh, Ryosuke; Sasada, Mahito, E-mail: haritma@iucaa.ernet.in [Hiroshima Astrophysical Science Center, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan)

2014-01-20

We present the results of photometric (V band) and polarimetric observations of the blazar BL Lac during 2008-2010 using TRISPEC attached to the KANATA 1.5 m telescope in Japan. The data reveal a great deal of variability ranging from days to months with detection of strong variations in fractional polarization. The V band flux strongly anticorrelates with the degree of polarization during the first of two observing seasons but not during the second. The direction of the electric vector, however, remained roughly constant during all of our observations. These results are consistent with a model with at least two emission regions being present, with the more variable component having a polarization direction nearly perpendicular to that of the relatively quiescent region so that a rising flux can produce a decline in degree of polarization. We also computed models involving helical jet structures and single transverse shocks in jets and show that they might also be able to agree with the anticorrelations between flux and fractional polarization.

Design review of the Brazilian Experimental Solar Telescope

Science.gov (United States)

Dal Lago, A.; Vieira, L. E. A.; Albuquerque, B.; Castilho, B.; Guarnieri, F. L.; Cardoso, F. R.; Guerrero, G.; Rodríguez, J. M.; Santos, J.; Costa, J. E. R.; Palacios, J.; da Silva, L.; Alves, L. R.; Costa, L. L.; Sampaio, M.; Dias Silveira, M. V.; Domingues, M. O.; Rockenbach, M.; Aquino, M. C. O.; Soares, M. C. R.; Barbosa, M. J.; Mendes, O., Jr.; Jauer, P. R.; Branco, R.; Dallaqua, R.; Stekel, T. R. C.; Pinto, T. S. N.; Menconi, V. E.; Souza, V. M. C. E. S.; Gonzalez, W.; Rigozo, N.

2015-12-01

The Brazilian's National Institute for Space Research (INPE), in collaboration with the Engineering School of Lorena/University of São Paulo (EEL/USP), the Federal University of Minas Gerais (UFMG), and the Brazilian's National Laboratory for Astrophysics (LNA), is developing a solar vector magnetograph and visible-light imager to study solar processes through observations of the solar surface magnetic field. The Brazilian Experimental Solar Telescope is designed to obtain full disk magnetic field and line-of-sight velocity observations in the photosphere. Here we discuss the system requirements and the first design review of the instrument. The instrument is composed by a Ritchey-Chrétien telescope with a 500 mm aperture and 4000 mm focal length. LCD polarization modulators will be employed for the polarization analysis and a tuning Fabry-Perot filter for the wavelength scanning near the Fe II 630.25 nm line. Two large field-of-view, high-resolution 5.5 megapixel sCMOS cameras will be employed as sensors. Additionally, we describe the project management and system engineering approaches employed in this project. As the magnetic field anchored at the solar surface produces most of the structures and energetic events in the upper solar atmosphere and significantly influences the heliosphere, the development of this instrument plays an important role in advancing scientific knowledge in this field. In particular, the Brazilian's Space Weather program will benefit most from the development of this technology. We expect that this project will be the starting point to establish a strong research program on Solar Physics in Brazil. Our main aim is to progressively acquire the know-how to build state-of-art solar vector magnetograph and visible-light imagers for space-based platforms.

THE VARIABLE NEAR-INFRARED COUNTERPART OF THE MICROQUASAR GRS 1758–258

International Nuclear Information System (INIS)

Luque-Escamilla, Pedro L.; Martí, Josep; Muñoz-Arjonilla, Álvaro J.

2014-01-01

We present a new study of the microquasar system GRS 1758–258 in the near-infrared domain based on archival observations with the Hubble Space Telescope and the NICMOS camera. In addition to confirming the near-infrared counterpart pointed out by Muñoz-Arjonilla et al., we show that this object displays significant photometric variability. From its average magnitudes, we also find that GRS 1758–258 fits well within the correlation between the optical/near-infrared and X-ray luminosity known to exist for low-mass, black-hole candidate X-ray binaries in a hard state. Moreover, the spectral energy distribution built using all radio, near-infrared, and X-ray data available closest in time to the NICMOS observations can be reasonably interpreted in terms of a self-absorbed radio jet and an irradiated accretion disk model around a stellar-mass black hole. All these facts match the expected behavior of a compact binary system and strengthen our confidence in the counterpart identification

The large binocular telescope.

Science.gov (United States)

Hill, John M

2010-06-01

The Large Binocular Telescope (LBT) Observatory is a collaboration among institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio, and Virginia. The telescope on Mount Graham in Southeastern Arizona uses two 8.4 m diameter primary mirrors mounted side by side. A unique feature of the LBT is that the light from the two Gregorian telescope sides can be combined to produce phased-array imaging of an extended field. This cophased imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65 m aperture and a collecting area equivalent to an 11.8 m circular aperture. This paper describes the design, construction, and commissioning of this unique telescope. We report some sample astronomical results with the prime focus cameras. We comment on some of the technical challenges and solutions. The telescope uses two F/15 adaptive secondaries to correct atmospheric turbulence. The first of these adaptive mirrors has completed final system testing in Firenze, Italy, and is planned to be at the telescope by Spring 2010.

Cryogenic implications of orbit selection of the Space Infrared Telescope Facility (SIRTF)

International Nuclear Information System (INIS)

Lee, J.H.; Brooke, W.F.; Maa, S.

1986-01-01

The Infrared Astronomical Satellite (IRAS) which completed the first all sky survey in the infrared demonstrated the tremendous advantage of space-based infrared astronomy. The ability to cool the telescope optics and focal plane to liquid helium temperatures and the absence of atmospheric disturbances which cause ''seeing'' effects resulted in the discovery of 250,000 IR sources and many interesting phenomena including dust clouds around Vega and the infrared ''cirrus'' at 100 μm. To realize the true benefit of space infrared astronomy, NASA is now studying the Space Infrared Telescope Facility, a long-life space-based observatory, to follow up on the survey results of IRAS. The choice of orbits is a critical program decision. The objective of this paper is to compare the performance of an all superfluid helium SIRTF system in the two possible orbit inclinations, polar orbit (99 0 ) and the low inclination orbit (28.5 0 )

LINEAR POLARIZATION OF CLASS I METHANOL MASERS IN MASSIVE STAR-FORMING REGIONS

International Nuclear Information System (INIS)

Kang, Ji-hyun; Byun, Do-Young; Kim, Kee-Tae; Kim, Jongsoo; Lyo, A-Ran; Vlemmings, W. H. T.

2016-01-01

Class I methanol masers are found to be good tracers of the interaction between outflows from massive young stellar objects with their surrounding media. Although polarization observations of Class II methanol masers have been able to provide information about magnetic fields close to the central (proto)stars, polarization observations of Class I methanol masers are rare, especially at 44 and 95 GHz. We present the results of linear polarization observations of 39 Class I methanol maser sources at 44 and 95 GHz. These two lines are observed simultaneously with one of the 21 m Korean VLBI Network telescopes in single-dish mode. Approximately 60% of the observed sources have fractional polarizations of a few percent in at least one transition. This is the first reported detection of linear polarization of the 44 GHz methanol maser. The two maser transitions show similar polarization properties, indicating that they trace similar magnetic environments, although the fraction of the linear polarization is slightly higher at 95 GHz. We discuss the association between the directions of polarization angles and outflows. We also discuss some targets having different polarization properties at both lines, including DR21(OH) and G82.58+0.20, which show the 90° polarization angle flip at 44 GHz.

IPOLE - semi-analytic scheme for relativistic polarized radiative transport

Science.gov (United States)

Mościbrodzka, M.; Gammie, C. F.

2018-03-01

We describe IPOLE, a new public ray-tracing code for covariant, polarized radiative transport. The code extends the IBOTHROS scheme for covariant, unpolarized transport using two representations of the polarized radiation field: In the coordinate frame, it parallel transports the coherency tensor; in the frame of the plasma it evolves the Stokes parameters under emission, absorption, and Faraday conversion. The transport step is implemented to be as spacetime- and coordinate- independent as possible. The emission, absorption, and Faraday conversion step is implemented using an analytic solution to the polarized transport equation with constant coefficients. As a result, IPOLE is stable, efficient, and produces a physically reasonable solution even for a step with high optical depth and Faraday depth. We show that the code matches analytic results in flat space, and that it produces results that converge to those produced by Dexter's GRTRANS polarized transport code on a complicated model problem. We expect IPOLE will mainly find applications in modelling Event Horizon Telescope sources, but it may also be useful in other relativistic transport problems such as modelling for the IXPE mission.

A Decade of MWC 758 Disk Images: Where Are the Spiral-arm-driving Planets?

Science.gov (United States)

Ren, Bin; Dong, Ruobing; Esposito, Thomas M.; Pueyo, Laurent; Debes, John H.; Poteet, Charles A.; Choquet, Élodie; Benisty, Myriam; Chiang, Eugene; Grady, Carol A.; Hines, Dean C.; Schneider, Glenn; Soummer, Rémi

2018-04-01

Large-scale spiral arms have been revealed in scattered light images of a few protoplanetary disks. Theoretical models suggest that such arms may be driven by and corotate with giant planets, which has called for remarkable observational efforts to look for them. By examining the rotation of the spiral arms for the MWC 758 system over a 10 year timescale, we are able to provide dynamical constraints on the locations of their perturbers. We present reprocessed Hubble Space Telescope (HST)/NICMOS F110W observations of the target in 2005, and the new Keck/NIRC2 L‧-band observations in 2017. MWC 758's two well-known spiral arms are revealed in the NICMOS archive at the earliest observational epoch. With additional Very Large Telescope (VLT)/SPHERE data, our joint analysis leads to a pattern speed of 0\\buildrel{\\circ}\\over{.} {6}-0\\buildrel{\\circ\\over{.} 6}+3\\buildrel{\\circ\\over{.} 3} {yr}}-1 at 3σ for the two major spiral arms. If the two arms are induced by a perturber on a near-circular orbit, its best-fit orbit is at 89 au (0.″59), with a 3σ lower limit of 30 au (0.″20). This finding is consistent with the simulation prediction of the location of an arm-driving planet for the two major arms in the system.

A 16-m Telescope for the Advanced Technology Large Aperture Telescope (ATLAST) Mission

Science.gov (United States)

Lillie, Charles F.; Dailey, D. R.; Polidan, R. S.

2010-01-01

Future space observatories will require increasingly large telescopes to study the earliest stars and galaxies, as well as faint nearby objects. Technologies now under development will enable telescopes much larger than the 6.5-meter diameter James Webb Space Telescope (JWST) to be developed at comparable costs. Current segmented mirror and deployable optics technology enables the 6.5 meter JWST telescope to be folded for launch in the 5-meter diameter Ariane 5 payload fairing, and deployed autonomously after reaching orbit. Late in the next decade, when the Ares V Cargo Launch Vehicle payload fairing becomes operational, even larger telescope can be placed in orbit. In this paper we present our concept for a 16-meter JWST derivative, chord-fold telescope which could be stowed in the 10-m diameter Ares V fairing, plus a description of the new technologies that enable ATLAST to be developed at an affordable price.

A 4-m evolvable space telescope configured for NASA's HabEx Mission: the initial stage of LUVOIR

Science.gov (United States)

Lillie, Charles F.; MacEwen, Howard A.; Polidan, Ronald S.; Breckinridge, James B.

2017-09-01

Previous papers have described our concept for a large telescope that would be assembled in space in several stages (in different configurations) over a period of fifteen to 20 years. Spreading the telescope development, launch and operations cost over 20 years would minimize the impact on NASA's annual budget and drastically shorten the time between program start and "first light" for this space observatory. The first Stage of this Evolvable Space Telescope (EST) would consist of an instrument module located at the prime focus of three 4-meter hexagonal mirrors arranged in a semi-circle to form one-half of a 12-m segmented mirror. After several years three additional 4-m mirrors would be added to create a 12-m filled aperture. Later, twelve more 4-m mirrors will be added to this Stage 2 telescope to create a 20-m filled aperture space telescope. At each stage the telescope would have an unparalleled capability for UVOIR observations, and the results of these observations will guide the evolution of the telescope and its instruments. In this paper we describe our design concept for an initial configuration of our Evolvable Space Telescope that can meet the requirements of the 4-m version of the HabEx spacecraft currently under consideration by NASA's Habitable Exoplanet Science and Technology Definition Team. This "Stage Zero" configuration will have only one 4-m mirror segment with the same 30-m focal length and a prime focus coronagraph with normal incidence optics to minimize polarization effects. After assembly and checkout in cis-lunar space, the telescope would transfer to a Sun-Earth L2 halo orbit and obtain high sensitivity, high resolution, high contrast UVOIR observations that address the scientific objectives of the Habitable-Exoplanet Imaging Missions.

Operating performance of the gamma-ray Cherenkov telescope: An end-to-end Schwarzschild–Couder telescope prototype for the Cherenkov Telescope Array

Energy Technology Data Exchange (ETDEWEB)

Dournaux, J.L., E-mail: jean-laurent.dournaux@obspm.fr [GEPI, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Paris Cité, Université Paris Diderot, Place J. Janssen, 92190 Meudon (France); De Franco, A. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Laporte, P. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Paris Cité, Université Paris Diderot, Place J. Janssen, 92190 Meudon (France); White, R. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Greenshaw, T. [University of Liverpool, Oliver Lodge Laboratory, P.O. Box 147, Oxford Street, Liverpool L69 3BX (United Kingdom); Sol, H. [LUTH, Observatoire de Paris, PSL Research University, CNRS, Université Paris Diderot, Place J. Janssen, 92190 Meudon (France); Abchiche, A. [CNRS, Division technique DT-INSU, 1 Place Aristide Briand, 92190 Meudon (France); Allan, D. [Department of Physics and Centre for Advanced Instrumentation, Durham University, South Road, Durham DH1 3LE (United Kingdom); Amans, J.P. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Paris Cité, Université Paris Diderot, Place J. Janssen, 92190 Meudon (France); Armstrong, T.P. [Department of Physics and Centre for Advanced Instrumentation, Durham University, South Road, Durham DH1 3LE (United Kingdom); Balzer, A.; Berge, D. [GRAPPA, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Boisson, C. [LUTH, Observatoire de Paris, PSL Research University, CNRS, Université Paris Diderot, Place J. Janssen, 92190 Meudon (France); and others

2017-02-11

The Cherenkov Telescope Array (CTA) consortium aims to build the next-generation ground-based very-high-energy gamma-ray observatory. The array will feature different sizes of telescopes allowing it to cover a wide gamma-ray energy band from about 20 GeV to above 100 TeV. The highest energies, above 5 TeV, will be covered by a large number of Small-Sized Telescopes (SSTs) with a field-of-view of around 9°. The Gamma-ray Cherenkov Telescope (GCT), based on Schwarzschild–Couder dual-mirror optics, is one of the three proposed SST designs. The GCT is described in this contribution and the first images of Cherenkov showers obtained using the telescope and its camera are presented. These were obtained in November 2015 in Meudon, France.

Radio Frequency Interference Site Survey for Thai Radio Telescopes

Science.gov (United States)

Jaroenjittichai, P.; Punyawarin, S.; Singwong, D.; Somboonpon, P.; Prasert, N.; Bandudej, K.; Kempet, P.; Leckngam, A.; Poshyachinda, S.; Soonthornthum, B.; Kramer, B.

2017-09-01

Radio astronomical observations have increasingly been threaten by the march of today telecommunication and wireless technology. Performance of radio telescopes lies within the fact that astronomical sources are extremely weak. National Astronomy Research Institute of Thailand (NARIT) has initiated a 5-year project, known as the Radio Astronomy Network and Geodesy for Development (RANGD), which includes the establishment of 40-meter and 13-meter radio telescopes. Possible locations have been narrowed down to three candidates, situated in the Northern part of Thailand, where the atmosphere is sufficiently dry and suitable for 22 and 43 GHz observations. The Radio Frequency Interference (RFI) measurements were carried out with a DC spectrum analyzer and directional antennas at 1.5 meter above ground, from 20 MHz to 6 GHz with full azimuth coverage. The data from a 3-minute pointing were recorded for both horizontal and vertical polarizations, in maxhold and average modes. The results, for which we used to make preliminary site selection, show signals from typical broadcast and telecommunication services and aeronautics applications. The signal intensity varies accordingly to the presence of nearby population and topography of the region.

TADPOL: A 1.3 mm Survey of Dust Polarization in Star-forming Cores and Regions

OpenAIRE

Hull, Charles L. H.; Plambeck, Richard L.; Kwon, Woojin; Bower, Geoffrey C.; Carpenter, John M.; Crutcher, Richard M.; Fiege, Jason D.; Franzmann, Erica; Hakobian, Nicholas S.; Heiles, Carl; Houde, Martin; Hughes, A. Meredith; Lamb, James W.; Looney, Leslie W.; Marrone, Daniel P.

2014-01-01

We present λ 1.3 mm Combined Array for Research in Millimeter-wave Astronomy observations of dust polarization toward 30 star-forming cores and eight star-forming regions from the TADPOL survey. We show maps of all sources, and compare the ~2".5 resolution TADPOL maps with ~20" resolution polarization maps from single-dish submillimeter telescopes. Here we do not attempt to interpret the detailed B-field morphology of each object. Rather, we use average B-field orientations to derive conclusi...

A satellite born charged particles telescope for the study of cosmic ray nuclei

Energy Technology Data Exchange (ETDEWEB)

De Pascale, M.P. [Rome Univ. `Tor Vergata` (Italy)]|[INFN, Rome (Italy); Bocciolini, M. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Barbiellini, G.; Boezio, M. [Trieste Univ. (Italy)]|[INFN, Trieste (Italy); Bellotti, R.; Cafagna, F. [Bari Univ. (Italy)]|[INFN, Bari (Italy)

1995-09-01

The description of the high energy particle telescope NINA for the study of cosmic ray nuclei is presented. The instrument will be installed on board of the Resource 01 satellite and will fly on a polar orbit at 690 Km. The telescope consists on a pile of 16 detecting planes each of them is composed by two silicon strip detectors with perpendicular strips and has a total area of 60x60mm{sup 2}. The experiment goals are the study of cosmic ray protons and nuclei in the energy range 12-100 MeV/amu. It will be sensitive to the anomalous component and will also make the observation of the large solar flare events and geophysical phenomena as well. This experiment is the first step of the program RIM whose goal is the satellite study of anti particles in primary cosmic rays.

MAGNETIC FIELD STRUCTURE OF THE LARGE MAGELLANIC CLOUD FROM FARADAY ROTATION MEASURES OF DIFFUSE POLARIZED EMISSION

Energy Technology Data Exchange (ETDEWEB)

Mao, S. A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); McClure-Griffiths, N. M.; McConnell, D. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Epping, NSW 1710 (Australia); Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Haverkorn, M. [Department of Astrophysics, Radboud University, P.O. Box 9010, 6500-GL Nijmegen (Netherlands); Beck, R. [Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn (Germany); Wolleben, M. [Square Kilometre Array South Africa, The Park, Pinelands 7405 (South Africa); Stanimirovic, S. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Dickey, J. M. [Physics Department, University of Tasmania, Hobart, TAS 7001 (Australia); Staveley-Smith, L., E-mail: mao@astro.wisc.edu [International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia, Crawley, WA 6009 (Australia)

2012-11-01

We present a study of the magnetic field of the Large Magellanic Cloud (LMC), carried out using diffuse polarized synchrotron emission data at 1.4 GHz acquired at the Parkes Radio Telescope and the Australia Telescope Compact Array. The observed diffuse polarized emission is likely to originate above the LMC disk on the near side of the galaxy. Consistent negative rotation measures (RMs) derived from the diffuse emission indicate that the line-of-sight magnetic field in the LMC's near-side halo is directed coherently away from us. In combination with RMs of extragalactic sources that lie behind the galaxy, we show that the LMC's large-scale magnetic field is likely to be of quadrupolar geometry, consistent with the prediction of dynamo theory. On smaller scales, we identify two brightly polarized filaments southeast of the LMC, associated with neutral hydrogen arms. The filaments' magnetic field potentially aligns with the direction toward the Small Magellanic Cloud (SMC). We suggest that tidal interactions between the SMC and the LMC in the past 10{sup 9} years are likely to have shaped the magnetic field in these filaments.

An innovative telescope control system architecture for SST-GATE telescopes at the CTA Observatory

Science.gov (United States)

Fasola, Gilles; Mignot, Shan; Laporte, Philippe; Abchiche, Abdel; Buchholtz, Gilles; Jégouzo, Isabelle

2014-07-01

SST-GATE (Small Size Telescope - GAmma-ray Telescope Elements) is a 4-metre telescope designed as a prototype for the Small Size Telescopes (SST) of the Cherenkov Telescope Array (CTA), a major facility for the very high energy gamma-ray astronomy of the next three decades. In this 100-telescope array there will be 70 SSTs, involving a design with an industrial view aiming at long-term service, low maintenance effort and reduced costs. More than a prototype, SST-GATE is also a fully functional telescope that shall be usable by scientists and students at the Observatoire de Meudon for 30 years. The Telescope Control System (TCS) is designed to work either as an element of a large array driven by an array controller or in a stand-alone mode with a remote workstation. Hence it is built to be autonomous with versatile interfacing; as an example, pointing and tracking —the main functions of the telescope— are managed onboard, including astronomical transformations, geometrical transformations (e.g. telescope bending model) and drive control. The core hardware is a CompactRIO (cRIO) featuring a real-time operating system and an FPGA. In this paper, we present an overview of the current status of the TCS. We especially focus on three items: the pointing computation implemented in the FPGA of the cRIO —using CORDIC algorithms— since it enables an optimisation of the hardware resources; data flow management based on OPCUA with its specific implementation on the cRIO; and the use of an EtherCAT field-bus for its ability to provide real-time data exchanges with the sensors and actuators distributed throughout the telescope.

PALOMA: A Magnetic CV between Polars and Intermediate Polars

Science.gov (United States)

Joshi, Arti; Pandey, J. C.; Singh, K. P.; Agrawal, P. C.

2016-10-01

We present analyses of archival X-ray data obtained from the XMM-Newton satellite and optical photometric data obtained from 1 m class telescopes of ARIES, Nainital of a magnetic cataclysmic variable (MCV) Paloma. Two persistent periods at 156 ± 1 minutes and 130 ± 1 minutes are present in the X-ray data, which we interpret as the orbital and spin periods, respectively. These periods are similar to those obtained from the previous as well as new optical photometric observations. The soft-X-ray excess seen in the X-ray spectrum of Paloma and the averaged X-ray spectra are well fitted by two-temperature plasma models with temperatures of {0.10}-0.01+0.02 and {13.0}-0.5+0.5 keV with an Fe Kα line and an absorbing column density of 4.6 × 1022 cm-2. This material partially covers 60 ± 2% of the X-ray source. We also present the orbital and spin-phase-resolved spectroscopy of Paloma in the 0.3{--}10.0 {keV} energy band and find that the X-ray spectral parameters show orbital and spin-phase dependencies. New results obtained from optical and X-ray studies of Paloma indicate that it belongs to a class of a few magnetic CVs that seem to have the characteristics of both the polars and the intermediate polars.

Classic Telescopes A Guide to Collecting, Restoring, and Using Telescopes of Yesteryear

CERN Document Server

English, Neil

2013-01-01

Classic Telescopes explores the exciting world of telescopes past, as well as the possibilities involved in acquiring these instruments. What are classic telescopes? First, the book takes a look at the more traditional telescopes built by the great instrument makers of the eighteenth and nineteenth centuries and the dynastic houses founded by the likes of John Dollond, Alvan Clark, Thomas Cooke & Sons and Carl Zeiss, plus some lesser-known luminaries, including John Brashear, John Calver, and Henry Fitz. Instruments constructed from the 1950s until as recently as the early 1990s are now also considered 'classic.' There is thus a very active market for buying and selling these 'modern' classics. The author examines some of the most talked about instruments on the amateur Internet forums, including the Unitron refractors, the Questar 90, a classic 6-inch reflector, the RV-6; a 3-inch F/15 achromat by Fullerscopes; the time-honored AstroScan Richfield reflector; and many, many more. Classic telescopes are of...

Alignment and phasing of deployable telescopes

Science.gov (United States)

Woolf, N. J.; Ulich, B. L.

1983-01-01

The experiences in coaligning and phasing the Multi-Mirror Telescope (MMT), together with studies in setting up radio telescopes, are presented. These experiences are discussed, and on the basis they furnish, schemes are suggested for coaligning and phasing four large future telescopes with complex primary mirror systems. These telescopes are MT2, a 15-m-equivalent MMT, the University of California Ten Meter Telescope, the 10 m sub-mm wave telescope of the University of Arizona and the Max Planck Institute for Radioastronomy, and the Large Deployable Reflector, a future space telescope for far-IR and sub-mm waves.

OVERVIEW OF THE ATACAMA COSMOLOGY TELESCOPE: RECEIVER, INSTRUMENTATION, AND TELESCOPE SYSTEMS

International Nuclear Information System (INIS)

Swetz, D. S.; Devlin, M. J.; Dicker, S. R.; Ade, P. A. R.; Amiri, M.; Battistelli, E. S.; Burger, B.; Halpern, M.; Hasselfield, M.; Appel, J. W.; Essinger-Hileman, T.; Fisher, R. P.; Fowler, J. W.; Hincks, A. D.; Jarosik, N.; Chervenak, J.; Doriese, W. B.; Hilton, G. C.; Irwin, K. D.; Duenner, R.

2011-01-01

The Atacama Cosmology Telescope was designed to measure small-scale anisotropies in the cosmic microwave background and detect galaxy clusters through the Sunyaev-Zel'dovich effect. The instrument is located on Cerro Toco in the Atacama Desert, at an altitude of 5190 m. A 6 m off-axis Gregorian telescope feeds a new type of cryogenic receiver, the Millimeter Bolometer Array Camera. The receiver features three 1000-element arrays of transition-edge sensor bolometers for observations at 148 GHz, 218 GHz, and 277 GHz. Each detector array is fed by free space millimeter-wave optics. Each frequency band has a field of view of approximately 22' x 26'. The telescope was commissioned in 2007 and has completed its third year of operations. We discuss the major components of the telescope, camera, and related systems, and summarize the instrument performance.

Overview of the Atacama Cosmology Telescope: Receiver, Instrumentation, and Telescope Systems

Science.gov (United States)

Swetz, D. S.; Ade, P. A. R.; Amiri, M.; Appel, J. W.; Battistelli, E. S.; Burger, B.; Chervenak, J.; Devlin, M. J.; Dicker, S. R.; Doriese, W. B.; Dünner, R.; Essinger-Hileman, T.; Fisher, R. P.; Fowler, J. W.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Hincks, A. D.; Irwin, K. D.; Jarosik, N.; Kaul, M.; Klein, J.; Lau, J. M.; Limon, M.; Marriage, T. A.; Marsden, D.; Martocci, K.; Mauskopf, P.; Moseley, H.; Netterfield, C. B.; Niemack, M. D.; Nolta, M. R.; Page, L. A.; Parker, L.; Staggs, S. T.; Stryzak, O.; Switzer, E. R.; Thornton, R.; Tucker, C.; Wollack, E.; Zhao, Y.

2011-06-01

The Atacama Cosmology Telescope was designed to measure small-scale anisotropies in the cosmic microwave background and detect galaxy clusters through the Sunyaev-Zel'dovich effect. The instrument is located on Cerro Toco in the Atacama Desert, at an altitude of 5190 m. A 6 m off-axis Gregorian telescope feeds a new type of cryogenic receiver, the Millimeter Bolometer Array Camera. The receiver features three 1000-element arrays of transition-edge sensor bolometers for observations at 148 GHz, 218 GHz, and 277 GHz. Each detector array is fed by free space millimeter-wave optics. Each frequency band has a field of view of approximately 22' × 26'. The telescope was commissioned in 2007 and has completed its third year of operations. We discuss the major components of the telescope, camera, and related systems, and summarize the instrument performance.

LIMITS ON OPTICAL POLARIZATION DURING THE PROMPT PHASE OF GRB 140430A

Energy Technology Data Exchange (ETDEWEB)

Kopac, D.; Mundell, C. G.; Arnold, D. M.; Steele, I. A.; Kobayashi, S.; Lamb, G. P.; Smith, R. J.; Virgili, F. J. [Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool, L3 5RF (United Kingdom); Japelj, J.; Gomboc, A. [Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Guidorzi, C.; Dichiara, S. [Department of Physics and Earth Sciences, University of Ferrara, via Saragat 1, I-44122, Ferrara (Italy); Harrison, R. M. [Department of Astrophysics, School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Melandri, A. [INAF—Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Italy); Castro-Tirado, A. J.; Gorosabel, J.; Sánchez-Ramírez, R.; Oates, S. R. [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Järvinen, A. [AIP—Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Jelínek, M., E-mail: drejc.kopac@fmf.uni-lj.si [ASU-CAS—Astronomical Institute of the Czech Academy of Sciences, Fričova 298, 251 65 Ondřejov (Czech Republic)

2015-11-01

Gamma-ray burst GRB 140430A was detected by the Swift satellite and observed promptly with the imaging polarimeter RINGO3 mounted on the Liverpool Telescope, with observations beginning while the prompt γ-ray emission was still ongoing. In this paper, we present densely sampled (10-s temporal resolution) early optical light curves (LCs) in 3 optical bands and limits to the degree of optical polarization. We compare optical, X-ray, and gamma-ray properties and present an analysis of the optical emission during a period of high-energy flaring. The complex optical LC cannot be explained merely with a combination of forward and reverse shock emission from a standard external shock, implying additional contribution of emission from internal shock dissipation. We estimate an upper limit for time averaged optical polarization during the prompt phase to be as low as P < 12% (1σ). This suggests that the optical flares and early afterglow emission in this GRB are not highly polarized. Alternatively, time averaging could mask the presence of otherwise polarized components of distinct origin at different polarization position angles.

LIMITS ON OPTICAL POLARIZATION DURING THE PROMPT PHASE OF GRB 140430A

International Nuclear Information System (INIS)

Kopac, D.; Mundell, C. G.; Arnold, D. M.; Steele, I. A.; Kobayashi, S.; Lamb, G. P.; Smith, R. J.; Virgili, F. J.; Japelj, J.; Gomboc, A.; Guidorzi, C.; Dichiara, S.; Harrison, R. M.; Melandri, A.; Castro-Tirado, A. J.; Gorosabel, J.; Sánchez-Ramírez, R.; Oates, S. R.; Järvinen, A.; Jelínek, M.

2015-01-01

Gamma-ray burst GRB 140430A was detected by the Swift satellite and observed promptly with the imaging polarimeter RINGO3 mounted on the Liverpool Telescope, with observations beginning while the prompt γ-ray emission was still ongoing. In this paper, we present densely sampled (10-s temporal resolution) early optical light curves (LCs) in 3 optical bands and limits to the degree of optical polarization. We compare optical, X-ray, and gamma-ray properties and present an analysis of the optical emission during a period of high-energy flaring. The complex optical LC cannot be explained merely with a combination of forward and reverse shock emission from a standard external shock, implying additional contribution of emission from internal shock dissipation. We estimate an upper limit for time averaged optical polarization during the prompt phase to be as low as P < 12% (1σ). This suggests that the optical flares and early afterglow emission in this GRB are not highly polarized. Alternatively, time averaging could mask the presence of otherwise polarized components of distinct origin at different polarization position angles

Alt-Az Spacewatch Telescope

Science.gov (United States)

Gehrels, Tom

1997-01-01

This grant funded about one third of the cost of the construction of a telescope with an aperture 1.8 meters in diameter to discover asteroids and comets and investigate the statistics of their populations and orbital distributions. This telescope has been built to the PI's specifications and installed in a dome on Kitt Peak mountain in Arizona. Funds for the dome and building were provided entirely by private sources. The dome building and telescope were dedicated in a ceremony at the site on June 7, 1997. The attached abstract describes the parameters of the telescope. The telescope is a new item of capital property. It is permanently located in University of Arizona building number 910 in the Steward Observatory compound on Kitt Peak mountain in the Tohono O'odham Nation, Arizona. fts property tag number is A252107. This grant did not include funds for the coma corrector lens, instrument derotator, CCD detector, detector electronics, or computers to acquire or process the data. It also did not include funds to operate the telescope or conduct research with it. Funds for these items and efforts are pending from NASA and other sources.

The great Melbourne telescope

CERN Document Server

Gillespie, Richard

2011-01-01

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

Lensing reconstruction from a patchwork of polarization maps

International Nuclear Information System (INIS)

Namikawa, Toshiya; Nagata, Ryo

2014-01-01

The lensing signals involved in CMB polarization maps have already been measured with ground-based experiments such as SPTpol and POLARBEAR, and would become important as a probe of cosmological and astrophysical issues in the near future. Sizes of polarization maps from ground-based experiments are, however, limited by contamination of long wavelength modes of observational noise. To further extract the lensing signals, we explore feasibility of measuring lensing signals from a collection of small sky maps each of which is observed separately by a ground-based large telescope, i.e., lensing reconstruction from a patchwork map of large sky coverage organized from small sky patches. We show that, although the B-mode power spectrum obtained from the patchwork map is biased due to baseline uncertainty, bias on the lensing potential would be negligible if the B-mode on scales larger than the blowup scale of 1/f noise is removed in the lensing reconstruction. As examples of cosmological applications, we also show 1) the cross-correlations between the reconstructed lensing potential and full-sky temperature/polarization maps from satellite missions such as PLANCK and LiteBIRD, and 2) the use of the reconstructed potential for delensing B-mode polarization of LiteBIRD observation

Scientific Performance Analysis of the SYZ Telescope Design versus the RC Telescope Design

Science.gov (United States)

Ma, Donglin; Cai, Zheng

2018-02-01

Recently, Su et al. propose an innovative design, referred as the “SYZ” design, for China’s new project of a 12 m optical-infrared telescope. The SYZ telescope design consists of three aspheric mirrors with non-zero power, including a relay mirror below the primary mirror. SYZ design yields a good imaging quality and has a relatively flat field curvature at Nasmyth focus. To evaluate the science-compatibility of this three-mirror telescope, in this paper, we thoroughly compare the performance of SYZ design with that of Ritchey–Chrétien (RC) design, a conventional two-mirror telescope design. Further, we propose the Observing Information Throughput (OIT) as a metric for quantitatively evaluating the telescopes’ science performance. We find that although a SYZ telescope yields a superb imaging quality over a large field of view, a two-mirror (RC) telescope design holds a higher overall throughput, a better diffraction-limited imaging quality in the central field of view (FOV < 5‧) which is better for the performance of extreme Adaptive Optics (AO), and a generally better scientific performance with a higher OIT value. D. Ma & Z. Cai contributed equally to this paper.

Testing the existence of optical linear polarization in young brown dwarfs

Science.gov (United States)

Manjavacas, E.; Miles-Páez, P. A.; Zapatero-Osorio, M. R.; Goldman, B.; Buenzli, E.; Henning, T.; Pallé, E.; Fang, M.

2017-07-01

Linear polarization can be used as a probe of the existence of atmospheric condensates in ultracool dwarfs. Models predict that the observed linear polarization increases with the degree of oblateness, which is inversely proportional to the surface gravity. We aimed to test the existence of optical linear polarization in a sample of bright young brown dwarfs, with spectral types between M6 and L2, observable from the Calar Alto Observatory, and cataloged previously as low gravity objects using spectroscopy. Linear polarimetric images were collected in I and R band using CAFOS at the 2.2-m telescope in Calar Alto Observatory (Spain). The flux ratio method was employed to determine the linear polarization degrees. With a confidence of 3σ, our data indicate that all targets have a linear polarimetry degree in average below 0.69 per cent in the I band, and below 1.0 per cent in the R band, at the time they were observed. We detected significant (I.e. P/σ ≥ 3) linear polarization for the young M6 dwarf 2MASS J04221413+1530525 in the R band, with a degree of p* = 0.81 ± 0.17 per cent.

Polarizing a stored proton beam by spin-flip?

International Nuclear Information System (INIS)

Oellers, Dieter Gerd Christian

2010-01-01

The present thesis discusses the extraction of the electron-proton spin-flip cross-section. The experimental setup, the data analysis and the results are pictured in detail. The proton is described by a QCD-based parton model. In leading twist three functions are needed. The quark distribution, the helicity distribution and the transversity distribution. While the first two are well-known, the transversity distribution is largely unknown. A self-sufficient measurement of the transversity is possible in double polarized proton-antiproton scattering. This rises the need of a polarized antiproton beam. So far spin filtering is the only tested method to produce a polarized proton beam, which may be capable to hold also for antiprotons. In-situ polarization build-up of a stored beam either by selective removal or by spin-flip of a spin-(1)/(2) beam is mathematically described. A high spin-flip cross-section would create an effective method to produce a polarized antiproton beam by polarized positrons. Prompted by conflicting calculations, a measurement of the spin-flip cross-section in low-energy electron-proton scattering was carried out. This experiment uses the electron beam of the electron cooler at COSY as an electron target. The depolarization of the stored proton beam is detected. An overview of the experiment is followed by detailed descriptions of the cycle setup, of the electron target and the ANKE silicon tracking telescopes acting as a beam polarimeter. Elastic protondeuteron scattering is the analyzing reaction. The event selection is depicted and the beam polarization is calculated. Upper limits of the two electron-proton spin-flip cross-sections σ parallel and σ perpendicular to are deduced using the likelihood method. (orig.)

Southern Fireworks above ESO Telescopes

Science.gov (United States)

1999-05-01

New Insights from Observations of Mysterious Gamma-Ray Burst International teams of astronomers are now busy working on new and exciting data obtained during the last week with telescopes at the European Southern Observatory (ESO). Their object of study is the remnant of a mysterious cosmic explosion far out in space, first detected as a gigantic outburst of gamma rays on May 10. Gamma-Ray Bursters (GRBs) are brief flashes of very energetic radiation - they represent by far the most powerful type of explosion known in the Universe and their afterglow in optical light can be 10 million times brighter than the brightest supernovae [1]. The May 10 event ranks among the brightest one hundred of the over 2500 GRB's detected in the last decade. The new observations include detailed images and spectra from the VLT 8.2-m ANTU (UT1) telescope at Paranal, obtained at short notice during a special Target of Opportunity programme. This happened just over one month after that powerful telescope entered into regular service and demonstrates its great potential for exciting science. In particular, in an observational first, the VLT measured linear polarization of the light from the optical counterpart, indicating for the first time that synchrotron radiation is involved . It also determined a staggering distance of more than 7,000 million light-years to this GRB . The astronomers are optimistic that the extensive observations will help them to better understand the true nature of such a dramatic event and thus to bring them nearer to the solution of one of the greatest riddles of modern astrophysics. A prime example of international collaboration The present story is about important new results at the front-line of current research. At the same time, it is also a fine illustration of a successful collaboration among several international teams of astronomers and the very effective way modern science functions. It began on May 10, at 08:49 hrs Universal Time (UT), when the Burst

Performance of a Highly Sensitive, 19-element, Dual-polarization, Cryogenic L-band Phased-array Feed on the Green Bank Telescope

Science.gov (United States)

Roshi, D. Anish; Shillue, W.; Simon, B.; Warnick, K. F.; Jeffs, B.; Pisano, D. J.; Prestage, R.; White, S.; Fisher, J. R.; Morgan, M.; Black, R.; Burnett, M.; Diao, J.; Ruzindana, M.; van Tonder, V.; Hawkins, L.; Marganian, P.; Chamberlin, T.; Ray, J.; Pingel, N. M.; Rajwade, K.; Lorimer, D. R.; Rane, A.; Castro, J.; Groves, W.; Jensen, L.; Nelson, J. D.; Boyd, T.; Beasley, A. J.

2018-05-01

A new 1.4 GHz, 19-element, dual-polarization, cryogenic phased-array feed (PAF) radio astronomy receiver has been developed for the Robert C. Byrd Green Bank Telescope (GBT) as part of the Focal L-band Array for the GBT (FLAG) project. Commissioning observations of calibrator radio sources show that this receiver has the lowest reported beam-formed system temperature (T sys) normalized by aperture efficiency (η) of any phased-array receiver to date. The measured T sys/η is 25.4 ± 2.5 K near 1350 MHz for the boresight beam, which is comparable to the performance of the current 1.4 GHz cryogenic single-feed receiver on the GBT. The degradation in T sys/η at ∼4‧ (required for Nyquist sampling) and ∼8‧ offsets from the boresight is, respectively, ∼1% and ∼20% of the boresight value. The survey speed of the PAF with seven formed beams is larger by a factor between 2.1 and 7 compared to a single-beam system, depending on the observing application. The measured performance, both in frequency and offset from the boresight, qualitatively agrees with predictions from a rigorous electromagnetic model of the PAF. The astronomical utility of the receiver is demonstrated by observations of the pulsar B0329+54 and an extended H II region, the Rosette Nebula. The enhanced survey speed with the new PAF receiver will enable the GBT to carry out exciting new science, such as more efficient observations of diffuse, extended neutral hydrogen emission from galactic inflows and searches for fast radio bursts.

McDonald 2.1-m and CRTS Photometry of Eclipsing Polars

Science.gov (United States)

Wells, Natalie; Mason, Paul

2018-01-01

We present broadband optical photometry of five polars made using the 2.1-m telescope of McDonald Observatory. Four of the polars are eclipsing (EP Dra, FL Cet, V2301 Oph, and a Catalina Sky Survey (CSS) polar candidate). In addition, a pre-polar (MQ Dra) was observed. Typical integration times were 1-3 seconds with no dead time. At this time resolution, eclipse structure can be seen in both one- and two-pole accretors. McDonald 2.1-m data over several years is phased together with CSS photometry covering up to 7 years, in search of indications of period variation. Combining the high-resolution, high-speed photometry obtained using the ProEm camera on the McDonald 2.1-m with the sparse, but high-quality multi-year baseline photometry of the CSS places strong constraints on the time variability of the eclipse periods in these binary systems. In most cases, eclipse variations do not perfectly fit a linear ephemeris. We investigate the source of variations using standard O-C diagram techniques and period search algorithms.

First Observation of the Submillimeter Polarization Spectrum in a Translucent Molecular Cloud

Science.gov (United States)

Ashton, Peter C.; Ade, Peter A. R.; Angilè, Francesco E.; Benton, Steven J.; Devlin, Mark J.; Dober, Bradley; Fissel, Laura M.; Fukui, Yasuo; Galitzki, Nicholas; Gandilo, Natalie N.; Klein, Jeffrey; Korotkov, Andrei L.; Li, Zhi-Yun; Martin, Peter G.; Matthews, Tristan G.; Moncelsi, Lorenzo; Nakamura, Fumitaka; Netterfield, Calvin B.; Novak, Giles; Pascale, Enzo; Poidevin, Frédérick; Santos, Fabio P.; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A.; Soler, Juan D.; Thomas, Nicholas E.; Tucker, Carole E.; Tucker, Gregory S.; Ward-Thompson, Derek

2018-04-01

Polarized emission from aligned dust is a crucial tool for studies of magnetism in the ISM, but a troublesome contaminant for studies of cosmic microwave background polarization. In each case, an understanding of the significance of the polarization signal requires well-calibrated physical models of dust grains. Despite decades of progress in theory and observation, polarized dust models remain largely underconstrained. During its 2012 flight, the balloon-borne telescope BLASTPol obtained simultaneous broadband polarimetric maps of a translucent molecular cloud at 250, 350, and 500 μm. Combining these data with polarimetry from the Planck 850 μm band, we have produced a submillimeter polarization spectrum, the first for a cloud of this type. We find the polarization degree to be largely constant across the four bands. This result introduces a new observable with the potential to place strong empirical constraints on ISM dust polarization models in a previously inaccessible density regime. Compared to models by Draine & Fraisse, our result disfavors two of their models for which all polarization arises due only to aligned silicate grains. By creating simple models for polarized emission in a translucent cloud, we verify that extinction within the cloud should have only a small effect on the polarization spectrum shape, compared to the diffuse ISM. Thus, we expect the measured polarization spectrum to be a valid check on diffuse ISM dust models. The general flatness of the observed polarization spectrum suggests a challenge to models where temperature and alignment degree are strongly correlated across major dust components.

Deriving the polarization behavior of many-layer mirror coatings

Science.gov (United States)

White, Amanda J.; Harrington, David M.; Sueoka, Stacey R.

2018-06-01

End-to-end models of astronomical instrument performance are becoming commonplace to demonstrate feasibility and guarantee performance at large observatories. Astronomical techniques like adaptive optics and high contrast imaging have made great strides towards making detailed performance predictions, however, for polarimetric techniques, fundamental tools for predicting performance do not exist. One big missing piece is predicting the wavelength and field of view dependence of a many-mirror articulated optical system particularly with complex protected metal coatings. Predicting polarization performance of instruments requires combining metrology of mirror coatings, tools to create mirror coating models, and optical modeling software for polarized beam propagation. The inability to predict instrument induced polarization or to define polarization performance expectations has far reaching implications for up and coming major observatories, such as the Daniel K. Inouye Solar Telescope (DKIST), that aim to take polarization measurements at unprecedented sensitivity and resolution.Here we present a method for modelling the wavelength dependent refractive index of an optic using Berreman calculus - a mathematical formalism that describes how an electromagnetic field propagates through a birefringent medium. From Berreman calculus, we can better predict the Mueller matrix, diattenuation, and retardance of an arbitrary thicknesses of amorphous many-layer coatings as well as stacks of birefringent crystals from laboratory measurements. This will allow for the wavelength dependent refractive index to be accurately determined and the polarization behavior to be derived for a given optic.

Power spectrum analysis of polarized emission from the Canadian galactic plane survey

Energy Technology Data Exchange (ETDEWEB)

Stutz, R. A.; Rosolowsky, E. W. [University of British Columbia Okanagan, 3333 University Way, Kelowna BC, V1V 1V7 (Canada); Kothes, R.; Landecker, T. L. [National Research Council Canada, Dominion Radio Astrophysical Observatory, Box 248, Penticton, BC, V2A 6J9 (Canada)

2014-05-20

Angular power spectra are calculated and presented for the entirety of the Canadian Galactic Plane Survey polarization data set at 1.4 GHz covering an area of 1060 deg{sup 2}. The data analyzed are a combination of data from the 100 m Effelsberg Telescope, the 26 m Telescope at the Dominion Radio Astrophysical Observatory, and the Synthesis Telescope at the Dominion Radio Astrophysical Observatory, allowing all scales to be sampled down to arcminute resolution. The resulting power spectra cover multipoles from ℓ ≈ 60 to ℓ ≈ 10{sup 4} and display both a power-law component at low multipoles and a flattening at high multipoles from point sources. We fit the power spectrum with a model that accounts for these components and instrumental effects. The resulting power-law indices are found to have a mode of 2.3, similar to previous results. However, there are significant regional variations in the index, defying attempts to characterize the emission with a single value. The power-law index is found to increase away from the Galactic plane. A transition from small-scale to large-scale structure is evident at b = 9°, associated with the disk-halo transition in a 15° region around l = 108°. Localized variations in the index are found toward H II regions and supernova remnants, but the interpretation of these variations is inconclusive. The power in the polarized emission is anticorrelated with bright thermal emission (traced by Hα emission) indicating that the thermal emission depolarizes background synchrotron emission.

Virtual Telescope Alignment System

Data.gov (United States)

National Aeronautics and Space Administration — Next-generation space telescopes require two spacecraft to fly in a coordinated fashion in space forming a virtual telescope. Achieving and maintaining this precise...

James Webb Space Telescope Optical Telescope Element Mirror Development History and Results

Science.gov (United States)

Feinber, Lee D.; Clampin, Mark; Keski-Kuha, Ritva; Atkinson, Charlie; Texter, Scott; Bergeland, Mark; Gallagher, Benjamin B.

2012-01-01

In a little under a decade, the James Webb Space Telescope (JWST) program has designed, manufactured, assembled and tested 21 flight beryllium mirrors for the James Webb Space Telescope Optical Telescope Element. This paper will summarize the mirror development history starting with the selection of beryllium as the mirror material and ending with the final test results. It will provide an overview of the technological roadmap and schedules and the key challenges that were overcome. It will also provide a summary or the key tests that were performed and the results of these tests.

Advanced Source Deconvolution Methods for Compton Telescopes

Science.gov (United States)

Zoglauer, Andreas

The next generation of space telescopes utilizing Compton scattering for astrophysical observations is destined to one day unravel the mysteries behind Galactic nucleosynthesis, to determine the origin of the positron annihilation excess near the Galactic center, and to uncover the hidden emission mechanisms behind gamma-ray bursts. Besides astrophysics, Compton telescopes are establishing themselves in heliophysics, planetary sciences, medical imaging, accelerator physics, and environmental monitoring. Since the COMPTEL days, great advances in the achievable energy and position resolution were possible, creating an extremely vast, but also extremely sparsely sampled data space. Unfortunately, the optimum way to analyze the data from the next generation of Compton telescopes has not yet been found, which can retrieve all source parameters (location, spectrum, polarization, flux) and achieves the best possible resolution and sensitivity at the same time. This is especially important for all sciences objectives looking at the inner Galaxy: the large amount of expected sources, the high background (internal and Galactic diffuse emission), and the limited angular resolution, make it the most taxing case for data analysis. In general, two key challenges exist: First, what are the best data space representations to answer the specific science questions? Second, what is the best way to deconvolve the data to fully retrieve the source parameters? For modern Compton telescopes, the existing data space representations can either correctly reconstruct the absolute flux (binned mode) or achieve the best possible resolution (list-mode), both together were not possible up to now. Here we propose to develop a two-stage hybrid reconstruction method which combines the best aspects of both. Using a proof-of-concept implementation we can for the first time show that it is possible to alternate during each deconvolution step between a binned-mode approach to get the flux right and a

Rapid radio polarization variability in the quasar 0917 + 624

Energy Technology Data Exchange (ETDEWEB)

Quirrenbach, A.; Witzel, A.; Qian, S.J.; Krichbaum, T.; Hummel, C.A.; Alberdi, A. (Max-Planck-Institut fuer Radioastronomie, Bonn 1 (DE))

1989-12-01

We have made measurements of the total flux density and the polarization of the quasar 0917+624 with a sampling of {approx} 1 hour using the 100 m telescope of the Max-Planck-Institut fuer Radioastronomie (MPIfR) at 6 and 11 cm wavelength. The total flux density showed variations with an amplitude of {approx} 25% and a typical time scale of {approx} 1 day at both wavelengths. The polarized flux density P showed even more dramatic variations with an amplitude of a factor {approx} 3, correlated with the variability of the total flux density S, P being high whenever S was low and vice versa. At 6 cm wavelength a swing of the polarization position angle {chi} of 180{sup 0} wasobserved at a time when the total flux density showed a maximum. These findings make any extrinsic explanations of the effect (e.g. scattering in the interstellar medium) very unlikely. We discuss a model which gives an explanation of the observed variability in terms of shocks propagating in a magnetized jet.

IS THE POLAR REGION DIFFERENT FROM THE QUIET REGION OF THE SUN?

International Nuclear Information System (INIS)

Ito, Hiroaki; Shiota, Daikou; Tokumaru, Munetoshi; Fujiki, Ken'ichi; Tsuneta, Saku

2010-01-01

Observations of the polar region of the Sun are critically important for understanding the solar dynamo and the acceleration of solar wind. We carried out precise magnetic observations on both the north polar region and the quiet Sun at the east limb with the spectropolarimeter of the Solar Optical Telescope aboard Hinode to characterize the polar region with respect to the quiet Sun. The average area and the total magnetic flux of the kilo-Gauss magnetic concentrations in the polar region appear to be larger than those of the quiet Sun. The magnetic field vectors classified as vertical in the quiet Sun have symmetric histograms around zero in the strengths, showing balanced positive and negative fluxes, while the histogram in the north polar region is clearly asymmetric, showing a predominance of the negative polarity. The total magnetic flux of the polar region is larger than that of the quiet Sun. In contrast, the histogram of the horizontal magnetic fields is exactly the same for both the polar region and the quiet Sun. This is consistent with the idea that a local dynamo process is responsible for the horizontal magnetic fields. A high-resolution potential field extrapolation shows that the majority of magnetic field lines from the kG-patches in the polar region are open with a fanning-out structure very low in the atmosphere, while in the quiet Sun, almost all the field lines are closed.

Mechanical design of SST-GATE, a dual-mirror telescope for the Cherenkov Telescope Array

Science.gov (United States)

Dournaux, Jean-Laurent; Huet, Jean-Michel; Amans, Jean-Philippe; Dumas, Delphine; Laporte, Philippe; Sol, Hélène; Blake, Simon

2014-07-01

The Cherenkov Telescope Array (CTA) project aims to create the next generation Very High Energy (VHE) gamma-ray telescope array. It will be devoted to the observation of gamma rays over a wide band of energy, from a few tens of GeV to more than 100 TeV. Two sites are foreseen to view the whole sky where about 100 telescopes, composed of three different classes, related to the specific energy region to be investigated, will be installed. Among these, the Small Size class of Telescopes, SSTs, are devoted to the highest energy region, to beyond 100 TeV. Due to the large number of SSTs, their unit cost is an important parameter. At the Observatoire de Paris, we have designed a prototype of a Small Size Telescope named SST-GATE, based on the dual-mirror Schwarzschild-Couder optical formula, which has never before been implemented in the design of a telescope. Over the last two years, we developed a mechanical design for SST-GATE from the optical and preliminary mechanical designs made by the University of Durham. The integration of this telescope is currently in progress. Since the early stages of mechanical design of SST-GATE, finite element method has been used employing shape and topology optimization techniques to help design several elements of the telescope. This allowed optimization of the mechanical stiffness/mass ratio, leading to a lightweight and less expensive mechanical structure. These techniques and the resulting mechanical design are detailed in this paper. We will also describe the finite element analyses carried out to calculate the mechanical deformations and the stresses in the structure under observing and survival conditions.

Photometric intensity and polarization measurements of the solar corona.

Science.gov (United States)

Mcdougal, D. S.

1971-01-01

Use of a satellite photometric observatory (SPO) to measure the solar corona from Miahuatlan, Mexico during the Mar. 7, 1970, total eclipse of the sun. The SPO is equipped with a 24-in. Cassegrainian telescope, a four-channel photoelectric photometer, a Wollaston prism, and a rotating half-wave plate. Simultaneous measurements were made of the two orthogonal components of coronal light in the B and R bands of the UBVRI system. A 1-minute arc aperture was scanned from the lunar disk center out to five solar radii in a series of spirals of gradually increasing radius. For the first time, simultaneous multicolor intensity, degree, and angle of polarization profiles are computed from photoelectric measurements. Comparison of the variations of the measurements for each spiral scan yield a detailed picture of the intensity and polarization features in the K corona.

Cosmic microwave background polarization results from QUIET

International Nuclear Information System (INIS)

Buder, I.

2014-01-01

Despite the success of precision cosmology, cosmologists cannot fully explain the initial conditions of the Universe. Inflation, an exponential expansion in the first ∼ 10 -36 s, is a promising potential explanation. A generic prediction of inflation is odd-parity (B-mode) polarization in the cosmic microwave background (CMB). Q/U Imaging Experiment (QUIET) aimed at limiting or detecting this polarization. We built a pseudo-correlation microwave polarimeter as an array of mass-produced modules in the focal plane of a 1.4 m telescope. We used rotation around the absorbing ground screen, a new time-stream double-demodulation technique, and optimized optics in the design to reduce instrumental polarization. We observed with this instrument at the Atacama Plateau in Chile between October 2008 and December 2010. This paper describes the analysis and results of these observations from one of 2 parallel pipelines. We developed noise modeling, filtering and data selection following a blind-analysis strategy. Central to this strategy was a suite of null test, each motivated by a possible instrumental problem or systematic effect. We evaluated the systematic errors in the blind stage of the analysis before the result was known. We calculated the CMB power spectra using a pseudo-C l cross-correlation technique that suppressed contamination and made the result insensitive to noise bias. We measured the first 3 peaks of the E-mode spectrum at high significance and limited B-mode polarization. We measured the CMB polarization power at 25 ≤ l ≤ 975. We found no statistically significant deviation from ΛCDM model, and our results are consistent with zero BB and EB power. Systematic errors were well below our B-mode polarization limits. This systematic-error reduction was a strong demonstration of technology for application in more sensitive, next generation CMB experiments. (author)

Polarizing a stored proton beam by spin-flip?

Energy Technology Data Exchange (ETDEWEB)

Oellers, Dieter Gerd Christian

2010-04-15

The present thesis discusses the extraction of the electron-proton spin-flip cross-section. The experimental setup, the data analysis and the results are pictured in detail. The proton is described by a QCD-based parton model. In leading twist three functions are needed. The quark distribution, the helicity distribution and the transversity distribution. While the first two are well-known, the transversity distribution is largely unknown. A self-sufficient measurement of the transversity is possible in double polarized proton-antiproton scattering. This rises the need of a polarized antiproton beam. So far spin filtering is the only tested method to produce a polarized proton beam, which may be capable to hold also for antiprotons. In-situ polarization build-up of a stored beam either by selective removal or by spin-flip of a spin-(1)/(2) beam is mathematically described. A high spin-flip cross-section would create an effective method to produce a polarized antiproton beam by polarized positrons. Prompted by conflicting calculations, a measurement of the spin-flip cross-section in low-energy electron-proton scattering was carried out. This experiment uses the electron beam of the electron cooler at COSY as an electron target. The depolarization of the stored proton beam is detected. An overview of the experiment is followed by detailed descriptions of the cycle setup, of the electron target and the ANKE silicon tracking telescopes acting as a beam polarimeter. Elastic protondeuteron scattering is the analyzing reaction. The event selection is depicted and the beam polarization is calculated. Upper limits of the two electron-proton spin-flip cross-sections {sigma} {sub parallel} and {sigma} {sub perpendicular} {sub to} are deduced using the likelihood method. (orig.)

Circular polarization of light by planet Mercury and enantiomorphism of its surface minerals.

Science.gov (United States)

Meierhenrich, Uwe J; Thiemann, Wolfram H P; Barbier, Bernard; Brack, André; Alcaraz, Christian; Nahon, Laurent; Wolstencroft, Ray

2002-04-01

Different mechanisms for the generation of circular polarization by the surface of planets and satellites are described. The observed values for Venus, the Moon, Mars, and Jupiter obtained by photo-polarimetric measurements with Earth based telescopes, showed accordance with theory. However, for planet Mercury asymmetric parameters in the circular polarization were measured that do not fit with calculations. For BepiColombo, the ESA cornerstone mission 5 to Mercury, we propose to investigate this phenomenon using a concept which includes two instruments. The first instrument is a high-resolution optical polarimeter, capable to determine and map the circular polarization by remote scanning of Mercury's surface from the Mercury Planetary Orbiter MPO. The second instrument is an in situ sensor for the detection of the enantiomorphism of surface crystals and minerals, proposed to be included in the Mercury Lander MSE.

A synthetic aperture radio telescope for ICME observations as a potential payload of SPORT

Science.gov (United States)

Zhang, C.; Sun, W.; Liu, H.; Xiong, M.; Liu, Y. D.; Wu, J.

2013-12-01

We introduce a potential payload for the Solar Polar ORbit Telescope (SPORT), a space weather mission proposed by the National Space Science Center, Chinese Academy of Sciences. This is a synthetic aperture radio imager designed to detect radio emissions from interplanetary coronal mass ejections (ICMEs), which is expected to be an important instrument to monitor the propagation and evolution of ICMEs. The radio telescope applies a synthetic aperture interferometric technique to measure the brightness temperature of ICMEs. Theoretical calculations of the brightness temperature utilizing statistical properties of ICMEs and the background solar wind indicate that ICMEs within 0.35 AU from the Sun are detectable by a radio telescope at a frequency <= 150 MHz with a sensitivity of <=1 K. The telescope employs a time shared double rotation scan (also called a clock scan), where two coplanar antennas revolve around a fixed axis at different radius and speed, to fulfill sampling of the brightness temperature. An array of 4+4 elements with opposite scanning directions are developed for the radio telescope to achieve the required sensitivity (<=1K) within the imaging refreshing time (~30 minutes). This scan scheme is appropriate for a three-axis stabilized spacecraft platform while keeping a good sampling pattern. We also discuss how we select the operating frequency, which involves a trade-off between the engineering feasibility and the scientific goal. Our preliminary results indicate that the central frequency of 150 MHz with a bandwidth of 20 MHz, which requires arm lengths of the two groups of 14m and 16m, respectively, gives an angular resolution of 2°, a field of view of ×25° around the Sun, and a time resolution of 30 minutes.

NEAR-INFRARED LINEAR POLARIZATION OF ULTRACOOL DWARFS

International Nuclear Information System (INIS)

Zapatero Osorio, M. R.; Bejar, V. J. S.; Rebolo, R.; Acosta-Pulido, J. A.; Manchado, A.; Pena Ramirez, K.; Goldman, B.; Caballero, J. A.

2011-01-01

We report on near-infrared J- and H-band linear polarimetric photometry of eight ultracool dwarfs (two late-M, five L0-L7.5, and one T2.5) with known evidence for photometric variability due to dust clouds, anomalous red infrared colors, or low-gravity atmospheres. The polarimetric data were acquired with the LIRIS instrument on the William Herschel Telescope. We also provide mid-infrared photometry in the interval 3.4-24 μm for some targets obtained with Spitzer and WISE, which has allowed us to confirm the peculiar red colors of five sources in the sample. We can impose modest upper limits of 0.9% and 1.8% on the linear polarization degree for seven targets with a confidence of 99%. Only one source, 2MASS J02411151-0326587 (L0), appears to be strongly polarized (P ∼ 3%) in the J band with a significance level of P/σ P ∼ 10. The likely origin of its linearly polarized light and rather red infrared colors may reside in a surrounding disk with an asymmetric distribution of grains. Given its proximity (66 ± 8 pc), this object becomes an excellent target for the direct detection of the disk.

The first telescope of the HEGRA air Cherenkov imaging telescope array

International Nuclear Information System (INIS)

Mirzoyan, R.; Kankanian, R.; Krennrich, F.; Mueller, N.; Sander, H.; Sawallisch, P.; Aharonian, F.; Akhperjanian, A.; Beglarian, A.; Fernandez, J.; Fonseca, V.; Grewe, W.; Heusler, A.; Konopelko, A.K.; Lorenz, E.; Merck, M.; Plyasheshnikov, A.V.; Renker, D.; Samorski, M.; Sauerland, K.; Smarsch, E.; Stamm, W.; Ulrich, M.; Wiedner, C.A.; Wirth, H.

1994-01-01

In search of VHE γ ray emission from cosmic point sources a system of imaging Cherenkov telescopes is constructed at present on the Canarian island of La Palma; the first telescope has been operational since 1992. The Cherenkov light from air shower particles is collected by a 5 m 2 reflector. The camera at the focus contains 37 photomultipliers which sample the images of the Cherenkov flashes. The subsequent image analysis allows the discrimination of γ ray induced events from the much more abundant charged cosmic ray induced showers. The telescope has an effective energy threshold for γ showers of about 1.5 TeV. During the first year of operation a signal from the Crab nebula was detected. ((orig.))

First results of the Test-Bed Telescopes (TBT) project: Cebreros telescope commissioning

Science.gov (United States)

Ocaña, Francisco; Ibarra, Aitor; Racero, Elena; Montero, Ángel; Doubek, Jirí; Ruiz, Vicente

2016-07-01

The TBT project is being developed under ESA's General Studies and Technology Programme (GSTP), and shall implement a test-bed for the validation of an autonomous optical observing system in a realistic scenario within the Space Situational Awareness (SSA) programme of the European Space Agency (ESA). The goal of the project is to provide two fully robotic telescopes, which will serve as prototypes for development of a future network. The system consists of two telescopes, one in Spain and the second one in the Southern Hemisphere. The telescope is a fast astrograph with a large Field of View (FoV) of 2.5 x 2.5 square-degrees and a plate scale of 2.2 arcsec/pixel. The tube is mounted on a fast direct-drive mount moving with speed up to 20 degrees per second. The focal plane hosts a 2-port 4K x 4K back-illuminated CCD with readout speeds up to 1MHz per port. All these characteristics ensure good survey performance for transients and fast moving objects. Detection software and hardware are optimised for the detection of NEOs and objects in high Earth orbits (objects moving from 0.1-40 arcsec/second). Nominal exposures are in the range from 2 to 30 seconds, depending on the observational strategy. Part of the validation scenario involves the scheduling concept integrated in the robotic operations for both sensors. Every night it takes all the input needed and prepares a schedule following predefined rules allocating tasks for the telescopes. Telescopes are managed by RTS2 control software, that performs the real-time scheduling of the observation and manages all the devices at the observatory.1 At the end of the night the observing systems report astrometric positions and photometry of the objects detected. The first telescope was installed in Cebreros Satellite Tracking Station in mid-2015. It is currently in the commissioning phase and we present here the first results of the telescope. We evaluate the site characteristics and the performance of the TBT Cebreros

Infrared up-conversion telescope

DEFF Research Database (Denmark)

2014-01-01

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

Cosmology from CMB Polarization with POLARBEAR and the Simons Array

Science.gov (United States)

Barron, Darcy; POLARBEAR Collaboration

2018-01-01

POLARBEAR is a cosmic microwave background (CMB) polarization experiment located in the Atacama desert in Chile. The science goals of the POLARBEAR project are to do a deep search for CMB B-mode polarization created by inflationary gravitational waves, as well as characterize the CMB B-mode signal from gravitational lensing. POLARBEAR-1 started observations in 2012, and the POLARBEAR team has published a series of results from its first season of observations, including the first measurement of a non-zero B-mode polarization angular power spectrum, measured at sub-degree scales where the dominant signal is gravitational lensing of the CMB. Recently, we released an improved measurement of the B-mode polarization power spectrum, improving our band-power uncertainties by a factor of two, by adding new data from our second observing season and re-analyzing the combined data set.To further improve on these measurements, POLARBEAR is expanding to include an additional two telescopes with multi-chroic receivers observing at 95, 150, 220, and 270 GHz, known as the Simons Array. With high sensitivity and large sky coverage, the Simons Array will create a detailed survey of B-mode polarization, and its spectral information will be used to extract the CMB signal from astrophysical foregrounds. We will present the latest POLARBEAR results, as well as the status of development of the Simons Array and its expected capabilities.

Polarization Monitoring of the Lens System JVAS B0218+357

Directory of Open Access Journals (Sweden)

Andrew Biggs

2017-10-01

Full Text Available Monitoring of the lens system JVAS B0218+357 with the Fermi Gamma-ray Space Telescope measured a different time delay to that derived from radio observations. We have re-analysed three months of archival Very Large Array data to produce variability curves with an average sampling of one epoch per day in total flux, polarized flux and polarization position angle (PPA at 15, 8.4 and 5 GHz. The variability is particularly strong in polarized flux. Dense sampling and improved subtraction of the Einstein ring has allowed us to produce superior variability curves and a preliminary analysis has resulted in a time delay (11.5 days which agrees well with the γ -ray value. Both images of 0218+357 are subject to strong Faraday rotation and depolarization as a result of the radio waves passing through the interstellar medium of the spiral lens galaxy. Our data reveal frequency-dependent variations in the PPA that are different in each image and which must therefore result from variable Faraday rotation in the lens galaxy on timescales of a few days. Our analysis has revealed systematic errors in the polarization position angle measurements that strongly correlate with hour angle. Although we have been able to correct for these, we caution that all VLA polarization observations are potentially affected.

Parametric cost models for space telescopes

Science.gov (United States)

Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtnay

2017-11-01

Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.

Parametric Cost Models for Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtney

2010-01-01

Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.

Development of a mid-sized Schwarzschild-Couder Telescope for the Cherenkov Telescope Array

Energy Technology Data Exchange (ETDEWEB)

Cameron, Robert A.

2012-06-28

The Cherenkov Telescope Array (CTA) is a ground-based observatory for very high-energy (10 GeV to 100 TeV) gamma rays, planned for operation starting in 2018. It will be an array of dozens of optical telescopes, known as Atmospheric Cherenkov Telescopes (ACTs), of 8 m to 24 m diameter, deployed over an area of more than 1 square km, to detect flashes of Cherenkov light from showers initiated in the Earth's atmosphere by gamma rays. CTA will have improved angular resolution, a wider energy range, larger fields of view and an order of magnitude improvement in sensitivity over current ACT arrays such as H.E.S.S., MAGIC and VERITAS. Several institutions have proposed a research and development program to eventually contribute 36 medium-sized telescopes (9 m to 12 m diameter) to CTA to enhance and optimize its science performance. The program aims to construct a prototype of an innovative, Schwarzschild-Couder telescope (SCT) design that will allow much smaller and less expensive cameras and much larger fields of view than conventional Davies-Cotton designs, and will also include design and testing of camera electronics for the necessary advances in performance, reliability and cost. We report on the progress of the mid-sized SCT development program.

A telescope with augmented reality functions

Science.gov (United States)

Hou, Qichao; Cheng, Dewen; Wang, Qiwei; Wang, Yongtian

2016-10-01

This study introduces a telescope with virtual reality (VR) and augmented reality (AR) functions. In this telescope, information on the micro-display screen is integrated to the reticule of telescope through a beam splitter and is then received by the observer. The design and analysis of telescope optical system with AR and VR ability is accomplished and the opto-mechanical structure is designed. Finally, a proof-of-concept prototype is fabricated and demonstrated. The telescope has an exit pupil diameter of 6 mm at an eye relief of 19 mm, 6° field of view, 5 to 8 times visual magnification , and a 30° field of view of the virtual image.

Balloon-Borne Observations of the Polarization of the Cosmic Microwave Background

Science.gov (United States)

2003-01-01

This final report is confined to the sub-contract to Caltech, and does not cover work at the PI institution (PI John Ruhl, Case Western Reserve University). In our original proposal, we planned to fly BOOMERANG twice, in the 2000 / 2001 and 2002 / 2003 Austral LDB seasons. The first flight was to have used a newly developed detector technology: the Polarization Sensitive Bolometer (PSB). The second flight was to have used a yet more sophisticated technology: a polarization sensitive, antenna-coupled array (CAMWA). The development of both technologies proceeded more slowly than anticipated. In the end, we were successful in developing the PSB technology to maturity, integrating it into the payload, and flying the payload once during the 2002/2003 Austral season. The payload performed well during this flight, and analysis of the data is in progress. As originally proposed, we have also continued to work on analysis of the data from the 1998 flight, and several publications have resulted. Sufficient progress has been made on the CAMWA technology that we expect to be able to field it into an instrument in 2 to 3 years. However, ground-based telescopes now appear to be a more attractive platform for CMB polarimetry, owing to the longer integration times available. We thus anticipate first implementing CAMWA on a ground-based telescope at South Pole.

The Gemini 8-Meter Telescopes Project

Science.gov (United States)

Boroson, Todd A.

1995-05-01

The Gemini 8-Meter Telescopes Project is an international partnership to build and operate two 8-meter telescopes, one on Mauna Kea, Hawaii, and one on Cerro Pachon, Chile. The telescopes will be international facilities, open to the scientific communities of the six member countries, the United States (50%), the United Kingdom (25%), Canada (15%), Chile (5%), Argentina (2.5%), and Brazil (2.5%). The telescopes are designed to exploit the best atmospheric conditions at these excellent sites. Near diffraction limited performance will be delivered at 2.2 microns and longward, with minimal degradation of the best seeing conditions at shorter wavelengths. The telescopes and facilities are designed to achieve emissivity opportunity. First light for the Mauna Kea telescope is expected in late 1998, and for the Cerro Pachon telescope in mid-2000. This talk will report on construction progress, the instrumental capabilities, and operations strategies being considered. The Gemini 8-meter Telescopes Project is managed by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation which serves as executive agency for the Gemini partner countries. U.S. participation in the project is through the U.S. Gemini Program, a division of the National Optical Astronomy Observatories. NOAO is operated by AURA, Inc. under cooperative agreement with the National Science Foundation.

Pre-selecting muon events in the camera server of the ASTRI telescopes for the Cherenkov Telescope Array

Science.gov (United States)

Maccarone, Maria C.; Mineo, Teresa; Capalbi, Milvia; Conforti, Vito; Coffaro, Martina

2016-08-01

The Cherenkov Telescope Array (CTA) represents the next generation of ground based observatories for very high energy gamma ray astronomy. The CTA will consist of two arrays at two different sites, one in the northern and one in the southern hemisphere. The current CTA design foresees, in the southern site, the installation of many tens of imaging atmospheric Cherenkov telescopes of three different classes, namely large, medium, and small, so defined in relation to their mirror area; the northern hemisphere array would consist of few tens of the two larger telescope types. The telescopes will be equipped with cameras composed either of photomultipliers or silicon photomultipliers, and with different trigger and read-out electronics. In such a scenario, several different methods will be used for the telescopes' calibration. Nevertheless, the optical throughput of any CTA telescope, independently of its type, can be calibrated analyzing the characteristic image produced by local atmospheric highly energetic muons that induce the emission of Cherenkov light which is imaged as a ring onto the focal plane if their impact point is relatively close to the telescope optical axis. Large sized telescopes would be able to detect useful muon events under stereo coincidence and such stereo muon events will be directly addressed to the central CTA array data acquisition pipeline to be analyzed. For the medium and small sized telescopes, due to their smaller mirror area and large inter-telescope distance, the stereo coincidence rate will tend to zero; nevertheless, muon events will be detected by single telescopes that must therefore be able to identify them as possible useful calibration candidates, even if no stereo coincidence is available. This is the case for the ASTRI telescopes, proposed as pre-production units of the small size array of the CTA, which are able to detect muon events during regular data taking without requiring any dedicated trigger. We present two fast

Cost Modeling for Space Telescope

Science.gov (United States)

Stahl, H. Philip

2011-01-01

Parametric cost models are an important tool for planning missions, compare concepts and justify technology investments. This paper presents on-going efforts to develop single variable and multi-variable cost models for space telescope optical telescope assembly (OTA). These models are based on data collected from historical space telescope missions. Standard statistical methods are used to derive CERs for OTA cost versus aperture diameter and mass. The results are compared with previously published models.

Wide Field Infrared Survey Telescope [WFIRST]: telescope design and simulated performance

Science.gov (United States)

Goullioud, R.; Content, D. A.; Kuan, G. M.; Moore, J. D.; Chang, Z.; Sunada, E. T.; Villalvazo, J.; Hawk, J. P.; Armani, N. V.; Johnson, E. L.; Powell, C. A.

2012-09-01

The Wide Field Infrared Survey Telescope (WFIRST) mission concept was ranked first in new space astrophysics missions by the Astro2010 Decadal Survey, incorporating the Joint Dark Energy Mission payload concept and multiple science white papers. This mission is based on a space telescope at L2 studying exoplanets [via gravitational microlensing], probing dark energy, and surveying the near infrared sky. Since the release of the Astro2010 Decadal Survey, the team has been working with the WFIRST Science Definition Team to refine mission and payload concepts. We present the current interim reference mission point design of the payload, based on the use of a 1.3m unobscured aperture three mirror anastigmat form, with focal imaging and slit-less spectroscopy science channels. We also present the first results of Structural/Thermal/Optical performance modeling of the telescope point design.

Hartman Testing of X-Ray Telescopes

Science.gov (United States)

Saha, Timo T.; Biskasch, Michael; Zhang, William W.

2013-01-01

Hartmann testing of x-ray telescopes is a simple test method to retrieve and analyze alignment errors and low-order circumferential errors of x-ray telescopes and their components. A narrow slit is scanned along the circumference of the telescope in front of the mirror and the centroids of the images are calculated. From the centroid data, alignment errors, radius variation errors, and cone-angle variation errors can be calculated. Mean cone angle, mean radial height (average radius), and the focal length of the telescope can also be estimated if the centroid data is measured at multiple focal plane locations. In this paper we present the basic equations that are used in the analysis process. These equations can be applied to full circumference or segmented x-ray telescopes. We use the Optical Surface Analysis Code (OSAC) to model a segmented x-ray telescope and show that the derived equations and accompanying analysis retrieves the alignment errors and low order circumferential errors accurately.

SCIENTIFIC EFFICIENCY OF GROUND-BASED TELESCOPES

International Nuclear Information System (INIS)

Abt, Helmut A.

2012-01-01

I scanned the six major astronomical journals of 2008 for all 1589 papers that are based on new data obtained from ground-based optical/IR telescopes worldwide. Then I collected data on numbers of papers, citations to them in 3+ years, the most-cited papers, and annual operating costs. These data are assigned to four groups by telescope aperture. For instance, while the papers from telescopes with an aperture >7 m average 1.29 more citations than those with an aperture of 2 to 7 m) telescopes. I wonder why the large telescopes do so relatively poorly and suggest possible reasons. I also found that papers based on archival data, such as the Sloan Digital Sky Survey, produce 10.6% as many papers and 20.6% as many citations as those based on new data. Also, the 577.2 papers based on radio data produced 36.3% as many papers and 33.6% as many citations as the 1589 papers based on optical/IR telescopes.

The SUrvey for Pulsars and Extragalactic Radio Bursts III: Polarization properties of FRBs 160102 & 151230

Science.gov (United States)

Caleb, M.; Keane, E. F.; van Straten, W.; Kramer, M.; Macquart, J. P.; Bailes, M.; Barr, E. D.; Bhat, N. D. R.; Bhandari, S.; Burgay, M.; Farah, W.; Jameson, A.; Jankowski, F.; Johnston, S.; Petroff, E.; Possenti, A.; Stappers, B.; Tiburzi, C.; Krishnan, V. Venkatraman

2018-05-01

We report on the polarization properties of two fast radio bursts (FRBs): 151230 and 160102 discovered in the SUrvey for Pulsars and Extragalactic Radio Bursts (SUPERB) at the Parkes radio telescope. FRB 151230 is observed to be 6 ± 11% circularly polarized and 35 ± 13 % linearly polarized with a rotation measure (RM) consistent with zero. Conversely, FRB 160102 is observed to have a circular polarization fraction of 30 ± 11 %, linear polarization fraction of 84 ± 15 % for RM =-221(6) rad m-2 and the highest measured DM (2596.1 ± 0.3 pc cm-3) for an FRB to date. We examine possible progenitor models for FRB 160102 in extragalactic, non-cosmological and cosmological scenarios. After accounting for the Galactic foreground contribution, we estimate the intrinsic RM to be -256(9) rad m-2 in the low-redshift case and ˜-2.4 × 102 rad m-2 in the high-redshift case. We assess the relative likeliness of these scenarios and how each can be tested. We also place constraints on the scattering measure and study the impact of scattering on the signal's polarization position angle.

Robotic and Survey Telescopes

Science.gov (United States)

Woźniak, Przemysław

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

Amateur Telescope Making

Science.gov (United States)

Tonkin, Stephen

Many amateur astronomers make their own instruments, either because of financial considerations or because they are just interested. Amateur Telescope Making offers a variety of designs for telescopes, mounts and drives which are suitable for the home-constructor. The designs range from simple to advanced, but all are within the range of a moderately well-equipped home workshop. The book not only tells the reader what he can construct, but also what it is sensible to construct given what time is available commercially. Thus each chapter begins with reasons for undertaking the project, then looks at theoretical consideration before finishing with practical instructions and advice. An indication is given as to the skills required for the various projects. Appendices list reputable sources of (mail order) materials and components. The telescopes and mounts range from "shoestring" (very cheap) instruments to specialist devices that are unavailable commercially.

Review of lunar telescope studies at MSFC

Science.gov (United States)

Hilchey, John D.; Nein, Max E.

1993-09-01

In the near future astronomers can take advantage of the lunar surface as the new 'high ground' from which to study the universe. Optical telescopes placed and operated on the lunar surface would be successors to NASA's Great Observatories. Four telescopes, ranging in aperture from a 16-m, IR/Vis/UV observatory down to a 1-m, UV 'transit' instrument, have been studied by the Lunar Telescope Working Group and the LUTE (lunar telescope ultraviolet experiment) Task Team of the Marshall Space Flight Center (MSFC). This paper presents conceptual designs of the telescopes, provides descriptions of the telescope subsystem options selected for each concept, and outlines the potential evolution of their science capabilities.

The Submillimeter Telescope (SMT) project

International Nuclear Information System (INIS)

Martin, R.N.; Baars, J.W.M.

1990-01-01

To exploit the potential of submillimeter astronomy, the Submillimeter Telescope (SMT) will be located at an altitude of 3178 meters on Emerald Peak 75 miles northeast of Tucson in Southern Arizona. The instrument is an altazimuth mounted f/13.8 Cassegrain homology telescope with two Nasmyth and bent Cassegrain foci. It will have diffraction limited performance at a wavelength of 300 microns and an operating overall figure accuracy of 15 microns rms. An important feature of the SMT is the construction of the primary and secondary reflectors out of aluminum-core CFRP face sheet sandwich panels, and the reflector backup structure and secondary support out of CFRP structural elements. This modern technology provides both a means for reaching the required precision of the SMT for both night and day operation (basically because of the low coefficient of thermal expansion and high strength-to-weight ratio of CFRP) and a potential route for the realization of lightweight telescopes of even greater accuracy in the future. The SMT will be the highest accuracy radio telescope ever built (at least a factor of 2 more accurate than existing telescopes). In addition, the SMT will be the first 10 m-class submillimeter telescope with a surface designed for efficient measurements at the important 350 microns wavelength atmospheric window. 9 refs

History of Robotic and Remotely Operated Telescopes

Science.gov (United States)

Genet, Russell M.

2011-03-01

While automated instrument sequencers were employed on solar eclipse expeditions in the late 1800s, it wasn't until the 1960s that Art Code and associates at Wisconsin used a PDP minicomputer to automate an 8-inch photometric telescope. Although this pioneering project experienced frequent equipment failures and was shut down after a couple of years, it paved the way for the first space telescopes. Reliable microcomputers initiated the modern era of robotic telescopes. Louis Boyd and I applied single board microcomputers with 64K of RAM and floppy disk drives to telescope automation at the Fairborn Observatory, achieving reliable, fully robotic operation in 1983 that has continued uninterrupted for 28 years. In 1985 the Smithsonian Institution provided us with a suburb operating location on Mt. Hopkins in southern Arizona, while the National Science Foundation funded additional telescopes. Remote access to our multiple robotic telescopes at the Fairborn Observatory began in the late 1980s. The Fairborn Observatory, with its 14 fully robotic telescopes and staff of two (one full and one part time) illustrates the potential for low operating and maintenance costs. As the information capacity of the Internet has expanded, observational modes beyond simple differential photometry opened up, bringing us to the current era of real-time remote access to remote observatories and global observatory networks. Although initially confined to smaller telescopes, robotic operation and remote access are spreading to larger telescopes as telescopes from afar becomes the normal mode of operation.

Prospects for γ-ray imaging telescopes

International Nuclear Information System (INIS)

Carter, J.N.; Dean, A.J.; Ramsden, D.

1981-01-01

Apart from the requirement for a new, high angular-resolution gamma-ray telescope for the more precise location of known COS-B gamma-ray sources, there is also a need for another instrument that can be used in a search for the gamma-ray emission from specific X-ray-emitting objects. If there is to be any hope of relating gamma ray emission to specific candidate X-ray objects, then an angular resolution of typically a few minutes of arc is required to resolve adjacent sources in crowded regions of the sky such as the galactic centre. Efforts to improve the angular resolution of track-chamber telescopes are compared. For energies close to 1 MeV telescopes have either used collimators to restrict the field of view or have made use of the kinematics of the Compton scattering process to determine the direction of the incident photon. The use of coded aperture techniques in high angular resolution X-ray astronomy telescopes is reviewed. A practical telescope for astronomy at high energies described by Carter is mentioned. At low energies an imaging telescope could be constructed by making use of position-sensitive detectors initially developed for use in medical physics. Such a telescope is outlined in general terms and its benefits and uses given. (U.K.)

HUBBLE SPACE TELESCOPE PRE-PERIHELION ACS/WFC IMAGING POLARIMETRY OF COMET ISON (C/2012 S1) AT 3.81 AU

Energy Technology Data Exchange (ETDEWEB)

Hines, Dean C.; Mutchler, Max; Hammer, Derek [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Videen, Gorden; Sitko, Michael L.; Yanamandra-Fisher, Padmavati A. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Zubko, Evgenij; Muinonen, Karri [Department of Physics, P.O. Box 64, FI-00014 University of Helsinki (Finland); Shkuratov, Yuriy; Kaydash, Vadim G. [Astronomical Institute of V. N. Karazin University, Kharkov, 61058 (Ukraine); Knight, Matthew M. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Lisse, Carey M. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States)

2014-01-10

We present polarization images of Comet ISON (C/2012 S1) taken with the Hubble Space Telescope (HST) on UTC 2013 May 8 (r {sub h} = 3.81 AU, Δ = 4.34 AU), when the phase angle was α ≈ 12.°16. This phase angle is approximately centered in the negative polarization branch for cometary dust. The region beyond 1000 km (∼0.32 arcsec ≈ 6 pixels) from the nucleus shows a negative polarization amplitude of p% ∼ –1.6%. Within 1000 km of the nucleus, the polarization position angle rotates to be approximately perpendicular to the scattering plane, with an amplitude p% ∼ +2.5%. Such positive polarization has been observed previously as a characteristic feature of cometary jets, and we show that Comet ISON does indeed harbor a jet-like feature. These HST observations of Comet ISON represent the first visible light, imaging polarimetry with subarcsecond spatial resolution of a Nearly Isotropic Comet beyond 3.8 AU from the Sun at a small phase angle. The observations provide an early glimpse of the properties of the cometary dust preserved in this Oort-Cloud comet.

Status of the MAGIC telescopes

Energy Technology Data Exchange (ETDEWEB)

Colin, Pierre; Carmona, Emiliano; Schweizer, Thomas; Sitarek, Julian [Max-Planck-Institut fuer Physik, Werner-Heisenberg Institut, Muenchen (Germany)

2010-07-01

MAGIC is a system of two 17-m Cherenkov telescopes located on La Palma (Canary islands),sensitive to gamma-rays above 30 GeV. It has been recently upgraded by a second telescope which strongly improves the sensitivity, particularly at low energy. Here we present the status of the MAGIC telescopes and an overview of the recent results obtained in single or stereoscopic mode. We also discuss the real performance of the new stereoscopic system based on Crab Nebula observations.

Performance of the Multi-Spectral Solar Telescope Array. III - Optical characteristics of the Ritchey-Chretien and Cassegrain telescopes

Science.gov (United States)

Hoover, Richard B.; Baker, Phillip C.; Hadaway, James B.; Johnson, R. B.; Peterson, Cynthia; Gabardi, David R.; Walker, Arthur B., Jr.; Lindblom, J. F.; Deforest, Craig; O'Neal, R. H.

1991-12-01

The Multi-Spectral Solar Telescope Array (MSSTA), which is a sounding-rocket-borne observatory for investigating the sun in the soft X-ray/EUV and FUV regimes of the electromagnetic spectrum, utilizes single reflection multilayer coated Herschelian telescopes for wavelengths below 100 A, and five doubly reflecting multilayer coated Ritchey-Chretien and two Cassegrain telescopes for selected wavelengths in the EUV region between 100 and 1000 A. The paper discusses the interferometric alignment, testing, focusing, visible light testing, and optical performance characteristics of the Ritchey-Chretien and Cassegrain telescopes of MSSTA. A schematic diagram of the MSSTA Ritchey-Chretien telescope is presented together with diagrams of the system autocollimation testing.

Telescopes and Techniques

CERN Document Server

Kitchin, C R

2013-01-01

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

The South Pole Telescope

Energy Technology Data Exchange (ETDEWEB)

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

2004-11-04

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

Commissioning and first tests of the MAGIC telescope

Science.gov (United States)

Baixeras, C.; Bastieri, D.; Bigongiari, C.; Blanch, O.; Blanchot, G.; Bock, R.; Bretz, T.; Chilingarian, A.; Coarasa, J. A.; Colombo, E.; Contreras, J. C.; Corti, D.; Cortina, J.; Domingo, C.; Domingo, E.; Ferenc, D.; Fernández, E.; Flix, J.; Fonseca, V.; Font, L.; Galante, N.; Gaug, M.; Garczarczyk, M.; Gebauer, J.; Giller, M.; Goebel, F.; Hengstebeck, T.; Jacone, P.; de Jager, O. C.; Kalekin, O.; Kestel, M.; Kneiske, T.; Laille, A.; López, M.; López, J.; Lorenz, E.; Mannheim, K.; Mariotti, M.; Martínez, M.; Mase, K.; Merck, M.; Meucci, M.; Miralles, L.; Mirzoyan, R.; Moralejo, A.; Wilhelmi, E. Oña; Orduña, R.; Paneque, D.; Paoletti, R.; Pascoli, D.; Pavel, N.; Pegna, R.; Peruzzo, L.; Piccioli, A.; Roberts, A.; Reyes, R.; Saggion, A.; Sánchez, A.; Sartori, P.; Scalzotto, V.; Schweizer, T.; Sillanpaa, A.; Sobczynska, D.; Stamerra, A.; Stepanian, A.; Stiehler, R.; Takalo, L.; Teshima, M.; Tonello, N.; Torres, A.; Turini, N.; Vitale, V.; Volkov, S.; Wagner, R. M.; Wibig, T.; Wittek, W.

2004-02-01

Major Atmospheric Gamma Imaging Cherenkov telescope is starting its operations with a set of engineering runs to tune the telescope subsystem elements to be ready for the first physics campaign. Many technical improvements have been developed and implemented in several elements of the telescope to reach the lowest energy threshold ever obtained by an Imaging Atmospheric Cherenkov Telescope. A general description of the telescope is presented. The commissioning of the telescope's elements is described and the expected performances are reviewed with the final detector set-up.

The Green Bank Telescope: Transformational Science for the Next Decade.

Science.gov (United States)

Wootten, Al; GBO Staff

2018-01-01

The Robert C Byrd Green Bank Telescope has met its design goal of providing high-quality observations at 115 GHz. The accurate small beam of the telescope at high frequencies is leveraged by deployment of multi beam receivers. An overview is presented. Observers now have access to the new, 16-pixel, 3-mm Argus receiver, which is providing high-dynamic range images over wide fields for the multitude of spectral lines between 85 and 115 GHz. The successful performance of Argus, and its modular design, demonstrates that receivers with many more pixels could be built for the GBT. A 12 x 12 array of the Argus design would have mapping speeds about nine times faster than Argus without suffering any degradation in performance for the outer pixels in the array. The Observatory plans to build the next-generation Argus instrument (Argus+) with 144-pixels, a footprint 5'x5', and 7" resolution at 110 GHz. The project will be a collaboration between the Green Bank Observatory and university groups, who will supply key components. The key science drivers for Argus+ are studies of molecular filaments in the Milky Way, studies of molecular clouds in nearby galaxies, and the observations of rapidly evolving solar system objects. Observers also have access to MUSTANG-2, a 223-feedhorn bolometer camera which was commissioned on the GBT in spring 2016, and was offered for observations on a shared risk basis, in collaboration with the instrument team, in the 2018A GBO proposal call. Several features distinguish it from its predecessor, MUSTANG: A new, microstrip-coupled detector design yields higher sensitivity and less susceptibility to environmental microphonics. Detectors are feedhorn coupled, with the sum of two linear polarizations measured by a single TES per feed. The instantaneous field of view is 4 arcminutes (vs 42 arcseconds for MUSTANG) The receiver design incorporates a tilted refrigerator and receiver rotator, resulting in much lower dependence of cooling performance on

SOUTH POL: Revealing the Polarized Southern Sky

Science.gov (United States)

Magalhaes, Antonio Mario Mario; Ramírez, Edgar; Ribeiro, Nadili; Seriacopi, Daiane; Rubinho, Marcelo; Ferrari, Tiberio; Rodrigues, Claudia; Schoenell, William; Herpich, Fabio; Pereyra, Antonio

2018-01-01

SOUTH POL will be a survey of the Southern sky in optical polarized light. It will use a newly built polarimeter for T80-S, an 84 cm robotic telescope installed at Cerro Tololo (CTIO), Chile. It will initially cover the sky South of declination -15 deg with a polarimetric accuracy Solar System.The polarimeter has just been commissioned in mid-November, 2017. The data reduction pipeline has already been built. We will describe the instrument and the data reduction, as well as a few of the science cases. The survey is expected to begin midway through the 1st semester of 2018. Both catalog data and raw images will be made available.

European Extremely Large Telescope: progress report

Science.gov (United States)

Tamai, R.; Spyromilio, J.

2014-07-01

The European Extremely Large Telescope is a project of the European Southern Observatory to build and operate a 40-m class optical near-infrared telescope. The telescope design effort is largely concluded and construction contracts are being placed with industry and academic/research institutes for the various components. The siting of the telescope in Northern Chile close to the Paranal site allows for an integrated operation of the facility providing significant economies. The progress of the project in various areas is presented in this paper and references to other papers at this SPIE meeting are made.

Preliminary Cost Model for Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Prince, F. Andrew; Smart, Christian; Stephens, Kyle; Henrichs, Todd

2009-01-01

Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. However, great care is required. Some space telescope cost models, such as those based only on mass, lack sufficient detail to support such analysis and may lead to inaccurate conclusions. Similarly, using ground based telescope models which include the dome cost will also lead to inaccurate conclusions. This paper reviews current and historical models. Then, based on data from 22 different NASA space telescopes, this paper tests those models and presents preliminary analysis of single and multi-variable space telescope cost models.

MASTER OPTICAL POLARIZATION VARIABILITY DETECTION IN THE MICROQUASAR V404 CYG/GS 2023+33

Energy Technology Data Exchange (ETDEWEB)

Lipunov, Vladimir M.; Kornilov, V.; Vlasenko, D. [M.V. Lomonosov Moscow State University, Physics Department, Leninskie gory, GSP-1, Moscow, 119991 (Russian Federation); Gorbovskoy, E.; Tiurina, N.; Balanutsa, P.; Kuznetsov, A. [M.V. Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr., 13, Moscow, 119234 (Russian Federation); Krushinskiy, V. [Kourovka Astronomical Observatory, Ural Federal University, Lenin ave. 51, Ekaterinburg 620000 (Russian Federation); Budnev, N.; Gress, O.; Ivanov, K.; Yazev, S. [Applied Physics Institute, Irkutsk State University, 20, Gagarin blvd, 664003, Irkutsk (Russian Federation); Tlatov, A. [Kislovodsk Solar Station of the Main (Pulkovo) Observatory RAS, P.O. Box 45, ul. Gagarina 100, Kislovodsk 357700 (Russian Federation); Rebolo Lopez, R.; Serra-Ricart, M.; Israelyan, G.; Lodieu, N. [Instituto de Astrofsica de Canarias, C/Via Lctea, s/n E-38205, La Laguna, Tenerife (Spain); Buckley, D. A. H. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935, Cape Town (South Africa); Sergienko, Yu.; Gabovich, A. [Blagoveschensk State Pedagogical University, Lenin str., 104, Amur Region, Blagoveschensk 675000 (Russian Federation); and others

2016-12-20

On 2015 June 15, the Swift space observatory discovered that the Galactic black hole candidate V404 Cyg was undergoing another active X-ray phase, after 25 years of inactivity. The 12 telescopes of the MASTER Global Robotic Net located at six sites across four continents were the first ground-based observatories to start optical monitoring of the microquasar after its gamma-ray wake up at 18{sup h} 34{sup m} 09{sup s} U.T. on 2015 June 15. In this paper, we report, for the first time, the discovery of variable optical linear polarization, changing by 4%–6% over a timescale of ∼1 hr, on two different epochs. We can conclude that the additional variable polarization arises from the relativistic jet generated by the black hole in V404 Cyg. The polarization variability correlates with optical brightness changes, increasing when the flux decreases.

Merz telescopes a global heritage worth preserving

CERN Document Server

2017-01-01

This book comprises a fascinating collection of contributions on the Merz telescopes in Italy that collectively offer the first survey on historical large refracting telescopes in the country, drawing on original documents and photographs. It opens with a general introduction on the importance of Merz telescopes in the history of astronomy and analyses of the local and international contexts in which the telescopes were made. After examination of an example of the interaction between the maker and the astronomer in the construction and maintenance of these refractors, the history of the Merz telescopes at the main Italian observatories in the nineteenth century is described in detail. Expert testimony is also provided on how these telescopes were successfully used until the second half of the twentieth century for research purposes, thus proving their excellent optical qualities.

SEPIA - a new single pixel receiver at the APEX telescope

Science.gov (United States)

Belitsky, V.; Lapkin, I.; Fredrixon, M.; Meledin, D.; Sundin, E.; Billade, B.; Ferm, S.-E.; Pavolotsky, A.; Rashid, H.; Strandberg, M.; Desmaris, V.; Ermakov, A.; Krause, S.; Olberg, M.; Aghdam, P.; Shafiee, S.; Bergman, P.; Beck, E. De; Olofsson, H.; Conway, J.; Breuck, C. De; Immer, K.; Yagoubov, P.; Montenegro-Montes, F. M.; Torstensson, K.; Pérez-Beaupuits, J.-P.; Klein, T.; Boland, W.; Baryshev, A. M.; Hesper, R.; Barkhof, J.; Adema, J.; Bekema, M. E.; Koops, A.

2018-04-01

Context. We describe the new Swedish-ESO PI Instrument for APEX (SEPIA) receiver, which was designed and built by the Group for Advanced Receiver Development (GARD), at Onsala Space Observatory (OSO) in collaboration with ESO. It was installed and commissioned at the APEX telescope during 2015 with an ALMA Band 5 receiver channel and updated with a new frequency channel (ALMA Band 9) in February 2016. Aim. This manuscript aims to provide, for observers who use the SEPIA receiver, a reference in terms of the hardware description, optics and performance as well as the commissioning results. Methods: Out of three available receiver cartridge positions in SEPIA, the two current frequency channels, corresponding to ALMA Band 5, the RF band 158-211 GHz, and Band 9, the RF band 600-722 GHz, provide state-of-the-art dual polarization receivers. The Band 5 frequency channel uses 2SB SIS mixers with an average SSB noise temperature around 45 K with IF (intermediate frequency) band 4-8 GHz for each sideband providing total 4 × 4 GHz IF band. The Band 9 frequency channel uses DSB SIS mixers with a noise temperature of 75-125 K with IF band 4-12 GHz for each polarization. Results: Both current SEPIA receiver channels are available to all APEX observers.

A coherent polarimeter array for the Large Scale Polarization Explorer balloon experiment

OpenAIRE

Bersanelli, M.; Mennella, A.; Morgante, G.; Zannoni, M.; Addamo, G.; Baschirotto, A.; Battaglia, P.; Baù, A.; Cappellini, B.; Cavaliere, F.; Cuttaia, F.; Del Torto, F.; Donzelli, S.; Farooqui, Z.; Frailis, M.

2012-01-01

We discuss the design and expected performance of STRIP (STRatospheric Italian Polarimeter), an array of coherent receivers designed to fly on board the LSPE (Large Scale Polarization Explorer) balloon experiment. The STRIP focal plane array comprises 49 elements in Q band and 7 elements in W-band using cryogenic HEMT low noise amplifiers and high performance waveguide components. In operation, the array will be cooled to 20 K and placed in the focal plane of a $\\sim 0.6$ meter telescope prov...

Open principle for large high-resolution solar telescopes

NARCIS (Netherlands)

Hammerschlag, R.H.; Bettonvil, F.C.M.; Jägers, A.P.L.; Sliepen, G.

2009-01-01

Vacuum solar telescopes solve the problem of image deterioration inside the telescope due to refractive index fluctuations of the air heated by the solar light. However, such telescopes have a practical diameter limit somewhat over 1 m. The Dutch Open Telescope (DOT) was the pioneering demonstrator

Optical Design of the STAR-X Telescope

Science.gov (United States)

Saha, Timo T.; Zhang, William W.; McClelland, Ryan S.

2017-01-01

Top-level science goals of the Survey and Time-domain Astrophysical Research eXplorer (STAR-X) include: investigations of most violent explosions in the universe, study of growth of black holes across cosmic time and mass scale, and measure how structure formation heats majority of baryons in the universe. To meet these goals, the field-of-view of the telescope should be about 1 square-degree, the angular resolution should be 5 arc-seconds or below across large part of the field-of-view. The on-axis effective area at 1 KeV should be about 2,000 sq cm. Payload cost and launch considerations limit the outer diameter, focal length, and mass to 1.3 meters, 5 meters, and 250 kilograms, respectively. Telescope design is based on a segmented meta-shell approach we have developed at Goddard Space Flight Center for the STAR-X telescope. The telescope shells are divided into 30-degree segments. Individual telescopes and meta-shells are nested inside each other to meet the effective area requirements in 0.5 - 6.0 KeV range. We consider Wolter-Schwarzschild, and Modified-Wolter-Schwarzschild telescope designs as basic building blocks of the nested STAR-X telescope. These designs offer an excellent resolution over a large field of views. Nested telescopes are vulnerable to stray light problems. We have designed a multi-component baffle system to eliminate direct and single-reflection light paths inside the telescopes. Large number of internal and external baffle vane structures are required to prevent stray rays from reaching the focal plane. We have developed a simple ray-trace based tool to determine the dimensions and locations of the baffles. In this paper, we present the results of our trade studies, baffle design studies, and optical performance analyses of the STAR-X telescope.

Optical polarization of high-energy BL Lacertae objects

Science.gov (United States)

Hovatta, T.; Lindfors, E.; Blinov, D.; Pavlidou, V.; Nilsson, K.; Kiehlmann, S.; Angelakis, E.; Fallah Ramazani, V.; Liodakis, I.; Myserlis, I.; Panopoulou, G. V.; Pursimo, T.

2016-12-01

Context. We investigate the optical polarization properties of high-energy BL Lac objects using data from the RoboPol blazar monitoring program and the Nordic Optical Telescope. Aims: We wish to understand if there are differences between the BL Lac objects that have been detected with the current-generation TeV instruments and those objects that have not yet been detected. Methods: We used a maximum-likelihood method to investigate the optical polarization fraction and its variability in these sources. In order to study the polarization position angle variability, we calculated the time derivative of the electric vector position angle (EVPA) change. We also studied the spread in the Stokes Q/I-U/I plane and rotations in the polarization plane. Results: The mean polarization fraction of the TeV-detected BL Lacs is 5%, while the non-TeV sources show a higher mean polarization fraction of 7%. This difference in polarization fraction disappears when the dilution by the unpolarized light of the host galaxy is accounted for. The TeV sources show somewhat lower fractional polarization variability amplitudes than the non-TeV sources. Also the fraction of sources with a smaller spread in the Q/I-U/I plane and a clumped distribution of points away from the origin, possibly indicating a preferred polarization angle, is larger in the TeV than in the non-TeV sources. These differences between TeV and non-TeV samples seem to arise from differences between intermediate and high spectral peaking sources instead of the TeV detection. When the EVPA variations are studied, the rate of EVPA change is similar in both samples. We detect significant EVPA rotations in both TeV and non-TeV sources, showing that rotations can occur in high spectral peaking BL Lac objects when the monitoring cadence is dense enough. Our simulations show that we cannot exclude a random walk origin for these rotations. Conclusions: These results indicate that there are no intrinsic differences in the

Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. IV. Measurement for Sculptor

Science.gov (United States)

Piatek, Slawomir; Pryor, Carlton; Bristow, Paul; Olszewski, Edward W.; Harris, Hugh C.; Mateo, Mario; Minniti, Dante; Tinney, Christopher G.

2006-03-01

This article presents a measurement of the proper motion of the Sculptor dwarf spheroidal galaxy determined from images taken with the Hubble Space Telescope using the Space Telescope Imaging Spectrograph in the imaging mode. Each of two distinct fields contains a quasi-stellar object that serves as the ``reference point.'' The measured proper motion of Sculptor, expressed in the equatorial coordinate system, is (μα, μδ)=(9+/-13, 2+/-13) mas century-1. Removing the contributions from the motion of the Sun and the motion of the local standard of rest produces the proper motion in the Galactic rest frame: (μGrfα, μGrfδ)=(-23+/-13, 45+/-13) mas century-1. The implied space velocity with respect to the Galactic center has a radial component of Vr=79+/-6 km s-1 and a tangential component of Vt=198+/-50 km s-1. Integrating the motion of Sculptor in a realistic potential for the Milky Way produces orbital elements. The perigalacticon and apogalacticon are 68 (31, 83) and 122 (97, 313) kpc, respectively, where the values in the parentheses represent the 95% confidence interval derived from Monte Carlo experiments. The eccentricity of the orbit is 0.29 (0.26, 0.60), and the orbital period is 2.2 (1.5, 4.9) Gyr. Sculptor is on a polar orbit around the Milky Way: the angle of inclination is 86° (83°, 90°). Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Technological Aspects of Creating Large-size Optical Telescopes

Directory of Open Access Journals (Sweden)

V. V. Sychev

2015-01-01

Full Text Available A concept of the telescope creation, first of all, depends both on a choice of the optical scheme to form optical radiation and images with minimum losses of energy and information and on a choice of design to meet requirements for strength, stiffness, and stabilization characteristics in real telescope operation conditions. Thus, the concept of creating large-size telescopes, certainly, involves the use of adaptive optics methods and means.The level of technological capabilities to realize scientific and engineering ideas define a successful development of large-size optical telescopes in many respects. All developers pursue the same aim that is to raise an amount of information by increasing a main mirror diameter of the telescope.The article analyses the adaptive telescope designs developed in our country. Using a domestic ACT-25 telescope as an example, it considers creation of large-size optical telescopes in terms of technological aspects. It also describes the telescope creation concept features, which allow reaching marginally possible characteristics to ensure maximum amount of information.The article compares a wide range of large-size telescopes projects. It shows that a domestic project to create the adaptive ACT-25 super-telescope surpasses its foreign counterparts, and there is no sense to implement Euro50 (50m and OWL (100m projects.The considered material gives clear understanding on a role of technological aspects in development of such complicated optic-electronic complexes as a large-size optical telescope. The technological criteria of an assessment offered in the article, namely specific informational content of the telescope, its specific mass, and specific cost allow us to reveal weaknesses in the project development and define a reserve regarding further improvement of the telescope.The analysis of results and their judgment have shown that improvement of optical largesize telescopes in terms of their maximum

Measurement of the circular polarization of gamma radiation from heavy ion collisions

International Nuclear Information System (INIS)

Lauterbach, C.

1981-01-01

For the nuclear reactions 16 O + 27 Al, 16 O + 58 Ni, 16 O + 62 Ni, 40 Ar + sup(nat)Ag, 86 Kr + sup(nat)Ag, and 86 Kr + 197 Au at incident energies of about 7 MeV/nucleon the circular polarization of the #betta# radiation emitted by the reaction products was measured. The projectile - like reaction products were detected by a δE-E telescope at a fixed angle of 35 0 relative to the beam axis. It is shown that the sign of the scattering angle for the classical orbit of the reaction partners can be determined by the experimental detection of circularly polarized #betta#-radiation from the decay of the highly excited reaction products. In the performed experiments for the first time extensive polarization phenomena in deep inelastic reactions were observed. The dominance of negative scattering angles was verified for a large range of light and medium-heavy systems. The results are compared with the predictions of theoretical models in which statistical or quantum mechanical fluctuations of the dynamical quantities are regarded. (orig./HSI) [de

Neutrino telescopes in the World

International Nuclear Information System (INIS)

Ernenwein, J.-P.

2007-01-01

Neutrino astronomy has rapidly developed these last years, being the only way to get specific and reliable information about astrophysical objects still poorly understood.Currently two neutrino telescopes are operational in the World: BAIKAL, in the lake of the same name in Siberia, and AMANDA, in the ices of the South Pole. Two telescopes of the same type are under construction in the Mediterranean Sea: ANTARES and NESTOR. All these telescopes belong to a first generation, with an instrumented volume smaller or equal to 0.02 km3. Also in the Mediterranean Sea, the NEMO project is just in its starting phase, within the framework of a cubic kilometer size neutrino telescope study. Lastly, the ICECUBE detector, with a volume reaching about 1 km3, is under construction on the site of AMANDA experiment, while an extension of the BAIKAL detector toward km3 is under study. We will present here the characteristics of these experiments, as well as the results of their observations

THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF RADIO SOURCES AT 43 AND 95 GHz

Energy Technology Data Exchange (ETDEWEB)

Huffenberger, K. M. [Department of Physics, Florida State University, P.O. Box 3064350, Tallahassee, FL 32306-4350 (United States); Araujo, D.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bischoff, C.; Buder, I. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Chinone, Y.; Hasegawa, M. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Blvd M/C 249-17, Pasadena, CA 91125 (United States); Kusaka, A. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Monsalve, R. [School of Earth and Space Exploration, Arizona State University, 781 E. Terrace Road, Tempe, AZ 85287 (United States); Næss, S. K. [Department of Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Newburgh, L. B. [Dunlap Institute, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Reeves, R. [CePIA, Departamento de Astronomía, Universidad de Concepción (Chile); Ruud, T. M.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Wehus, I. K.; Gaier, T. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Dickinson, C. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Gundersen, J. O., E-mail: huffenbe@physics.fsu.edu [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Collaboration: QUIET Collaboration; and others

2015-06-10

We present polarization measurements of extragalactic radio sources observed during the cosmic microwave background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼480 such sources within QUIET’s four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30–40 mJy per Stokes parameter. At signal-to-noise ratio > 3 significance, we detect linear polarization for seven sources in Q-band and six in W-band; only 1.3 ± 1.1 detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization measurements of the same sources from the literature. For the four sources with WMAP and Planck intensity measurements >1 Jy, the polarization fractions are above 1% in both QUIET bands. At high significance, we compute polarization fractions as much as 10%–20% for some sources, but the effects of source variability may cut that level in half for contemporaneous comparisons. Our results indicate that simple models—ones that scale a fixed polarization fraction with frequency—are inadequate to model the behavior of these sources and their contributions to polarization maps.

The Liverpool Telescope: rapid follow-up observation of targets of opportunity with a 2 m robotic telescope

International Nuclear Information System (INIS)

Gomboc, Andreja; Bode, Michael F.; Carter, David; Mundell, Carol G.; Newsam, Andrew; Smith, Robert J.; Steele, Iain A.

2004-01-01

The Liverpool Telescope, situated at Roque de los Muchachos Observatory, La Palma, Canaries, is the first 2-m, fully instrumented robotic telescope. It recently began observations. Among Liverpool Telescope's primary scientific goals is to monitor variable objects on all timescales from seconds to years. An additional benefit of its robotic operation is rapid reaction to unpredictable phenomena and their systematic follow up, simultaneous or coordinated with other facilities. The Target of Opportunity Programme of the Liverpool Telescope includes the prompt search for and observation of GRB and XRF counterparts. A special over-ride mode implemented for GRB/XRF follow-up enables observations commencing less than a minute after the alert, including optical and near infrared imaging and spectroscopy. In particular, the moderate aperture and rapid automated response make the Liverpool Telescope excellently suited to help solving the mystery of optically dark GRBs and for the investigation of currently unstudied short bursts and XRFs

HIGH-TIME-RESOLUTION MEASUREMENTS OF THE POLARIZATION OF THE CRAB PULSAR AT 1.38 GHz

Energy Technology Data Exchange (ETDEWEB)

Słowikowska, Agnieszka [Kepler Institute of Astronomy, University of Zielona Góra, Lubuska 2, 65-265 Zielona Góra (Poland); Stappers, Benjamin W. [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom); Harding, Alice K. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); O' Dell, Stephen L.; Elsner, Ronald F.; Weisskopf, Martin C. [Astrophysics Office, NASA Marshall Space Flight Center, ZP12, Huntsville, AL 35812 (United States); Van der Horst, Alexander J. [Astronomical Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands)

2015-01-20

Using the Westerbork Synthesis Radio Telescope, we obtained high-time-resolution measurements of the full polarization of the Crab pulsar. At a resolution of 1/8192 of the 34 ms pulse period (i.e., 4.1 μs), the 1.38 GHz linear-polarization measurements are in general agreement with previous lower-time-resolution 1.4 GHz measurements of linear polarization in the main pulse (MP), in the interpulse (IP), and in the low-frequency component (LFC). We find the MP and IP to be linearly polarized at about 24% and 21% with no discernible difference in polarization position angle. However, contrary to theoretical expectations and measurements in the visible, we find no evidence for significant variation (sweep) in the polarization position angle over the MP, the IP, or the LFC. We discuss the implications, which appear to be in contradiction to theoretical expectations. We also detect weak circular polarization in the MP and IP, and strong (≈20%) circular polarization in the LFC, which also exhibits very strong (≈98%) linear polarization at a position angle of 40° from that of the MP or IP. The properties are consistent with the LFC, which is a low-altitude component, and the MP and IP, which are high-altitude caustic components. Current models for the MP and IP emission do not readily account for the absence of pronounced polarization changes across the pulse. We measure IP and LFC pulse phases relative to the MP consistent with recent measurements, which have shown that the phases of these pulse components are evolving with time.

GREEN BANK TELESCOPE AND SWIFT X-RAY TELESCOPE OBSERVATIONS OF THE GALACTIC CENTER RADIO MAGNETAR SGR J1745–2900

Energy Technology Data Exchange (ETDEWEB)

Lynch, Ryan S.; Archibald, Robert F.; Kaspi, Victoria M.; Scholz, Paul, E-mail: rlynch@physics.mcgill.ca [Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8 (Canada)

2015-06-20

We present results from eight months of Green Bank Telescope 8.7 GHz observations and nearly 18 months of Swift X-ray telescope observations of the radio magnetar SGR J1745–2900. We tracked the radio and X-ray flux density, polarization properties, profile evolution, rotation, and single-pulse behavior. We identified two main periods of activity. The first is characterized by approximately 5.5 months of relatively stable evolution in radio flux density, rotation, and profile shape, while in the second these properties varied substantially. Specifically, a third profile component emerged and the radio flux also became more variable. The single pulse properties also changed, most notably with a larger fraction of pulses with pulse widths ∼5–20 ms in the erratic state. Bright single pulses are well described by a log-normal energy distribution at low energies, but with an excess at high energies. The 2–10 keV flux decayed steadily since the initial X-ray outburst, while the radio flux remained stable to within ∼20% during the stable state. A joint pulsar timing analysis of the radio and X-ray data shows a level of timing noise unprecedented in a radio magnetar, though during the time covered by the radio data alone the timing noise was at a level similar to that observed in other radio magnetars. While SGR J1745–2900 is similar to other radio magnetars in many regards, it differs by having experienced a period of relative stability in the radio that now appears to have ended, while the X-ray properties evolved independently.

IPHAS J062746.41+014811.3: A DEEPLY ECLIPSING INTERMEDIATE POLAR

International Nuclear Information System (INIS)

Aungwerojwit, A.; Gänsicke, B. T.; Wheatley, P. J.; Pyrzas, S.; Staels, B.; Krajci, T.; Rodríguez-Gil, P.

2012-01-01

We present time-resolved photometry of a cataclysmic variable discovered in the Isaac Newton Telescope Photometric Hα Survey of the northern galactic plane, IPHAS J062746.41+014811.3, and classify the system as the fourth deeply eclipsing intermediate polar known with an orbital period of P orb = 8.16 hr and a spin period of P spin = 2210 s. The system shows mild variations of its brightness that appear to be accompanied by a change in the amplitude of the spin modulation at optical wavelengths and a change in the morphology of the eclipse profile. The inferred magnetic moment of the white dwarf is μ wd ∼ (6-7) × 10 33 G cm 3 , and in this case IPHAS J062746.41+014811.3 will evolve either into a short-period EX Hya-like intermediate polar with a large P spin /P orb ratio or, perhaps more likely, into a synchronized polar. Swift observations show that the system is an ultraviolet and X-ray source, with a hard X-ray spectrum that is consistent with those seen in other intermediate polars. The ultraviolet light curve shows orbital modulation and an eclipse, while the low signal-to-noise ratio X-ray light curve does not show a significant modulation on the spin period. The measured X-ray flux is about an order of magnitude lower than would be expected from scaling by the optical fluxes of well-known X-ray-selected intermediate polars.

ANTARES: The first undersea neutrino telescope

Science.gov (United States)

Ageron, M.; Aguilar, J. A.; Al Samarai, I.; Albert, A.; Ameli, F.; André, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Arnaud, K.; Aslanides, E.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J.-J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Becherini, Y.; Beltramelli, J.; Bersani, A.; Bertin, V.; Beurthey, S.; Biagi, S.; Bigongiari, C.; Billault, M.; Blaes, R.; Bogazzi, C.; de Botton, N.; Bou-Cabo, M.; Boudahef, B.; Bouwhuis, M. C.; Brown, A. M.; Brunner, J.; Busto, J.; Caillat, L.; Calzas, A.; Camarena, F.; Capone, A.; Caponetto, L.; Cârloganu, C.; Carminati, G.; Carmona, E.; Carr, J.; Carton, P. H.; Cassano, B.; Castorina, E.; Cecchini, S.; Ceres, A.; Chaleil, Th.; Charvis, Ph.; Chauchot, P.; Chiarusi, T.; Circella, M.; Compère, C.; Coniglione, R.; Coppolani, X.; Cosquer, A.; Costantini, H.; Cottini, N.; Coyle, P.; Cuneo, S.; Curtil, C.; D'Amato, C.; Damy, G.; van Dantzig, R.; de Bonis, G.; Decock, G.; Decowski, M. P.; Dekeyser, I.; Delagnes, E.; Desages-Ardellier, F.; Deschamps, A.; Destelle, J.-J.; di Maria, F.; Dinkespiler, B.; Distefano, C.; Dominique, J.-L.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drogou, J.-F.; Drouhin, D.; Druillole, F.; Durand, D.; Durand, R.; Eberl, T.; Emanuele, U.; Engelen, J. J.; Ernenwein, J.-P.; Escoffier, S.; Falchini, E.; Favard, S.; Fehr, F.; Feinstein, F.; Ferri, M.; Ferry, S.; Fiorello, C.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J.-L.; Galatá, S.; Galeotti, S.; Gay, P.; Gensolen, F.; Giacomelli, G.; Gojak, C.; Gómez-González, J. P.; Goret, Ph.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Hartmann, B.; Heijboer, A. J.; Heine, E.; Hello, Y.; Henry, S.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; Hogenbirk, J.; Hsu, C. C.; Hubbard, J. R.; Jaquet, M.; Jaspers, M.; de Jong, M.; Jourde, D.; Kadler, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Karg, T.; Karkar, S.; Karolak, M.; Katz, U.; Keller, P.; Kestener, P.; Kok, E.; Kok, H.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Kruijer, A.; Kuch, S.; Kulikovskiy, V.; Lachartre, D.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lahonde-Hamdoun, C.; Lamare, P.; Lambard, G.; Languillat, J.-C.; Larosa, G.; Lavalle, J.; Le Guen, Y.; Le Provost, H.; Levansuu, A.; Lefèvre, D.; Legou, T.; Lelaizant, G.; Lévéque, C.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Lyashuk, V.; Magnier, P.; Mangano, S.; Marcel, A.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Masullo, R.; Mazéas, F.; Mazure, A.; Meli, A.; Melissas, M.; Migneco, E.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Neff, M.; Niess, V.; Nooren, G. J. L.; Oberski, J. E. J.; Olivetto, C.; Palanque-Delabrouille, N.; Palioselitis, D.; Papaleo, R.; Păvălaş, G. E.; Payet, K.; Payre, P.; Peek, H.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Picq, C.; Piret, Y.; Poinsignon, J.; Popa, V.; Pradier, T.; Presani, E.; Prono, G.; Racca, C.; Raia, G.; van Randwijk, J.; Real, D.; Reed, C.; Réthoré, F.; Rewiersma, P.; Riccobene, G.; Richardt, C.; Richter, R.; Ricol, J. S.; Rigaud, V.; Roca, V.; Roensch, K.; Rolin, J.-F.; Rostovtsev, A.; Rottura, A.; Roux, J.; Rujoiu, M.; Ruppi, M.; Russo, G. V.; Salesa, F.; Salomon, K.; Sapienza, P.; Schmitt, F.; Schöck, F.; Schuller, J.-P.; Schüssler, F.; Sciliberto, D.; Shanidze, R.; Shirokov, E.; Simeone, F.; Sottoriva, A.; Spies, A.; Spona, T.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Streeb, K.; Sulak, L.; Taiuti, M.; Tamburini, C.; Tao, C.; Tasca, L.; Terreni, G.; Tezier, D.; Toscano, S.; Urbano, F.; Valdy, P.; Vallage, B.; van Elewyck, V.; Vannoni, G.; Vecchi, M.; Venekamp, G.; Verlaat, B.; Vernin, P.; Virique, E.; de Vries, G.; van Wijk, R.; Wijnker, G.; Wobbe, G.; de Wolf, E.; Yakovenko, Y.; Yepes, H.; Zaborov, D.; Zaccone, H.; Zornoza, J. D.; Zúñiga, J.

2011-11-01

The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given.

ANTARES: The first undersea neutrino telescope

International Nuclear Information System (INIS)

Ageron, M.; Aguilar, J.A.; Al Samarai, I.; Albert, A.; Ameli, F.; Andre, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Arnaud, K.; Aslanides, E.; Assis Jesus, A.C.; Astraatmadja, T.; Aubert, J.-J.; Auer, R.; Barbarito, E.; Baret, B.

2011-01-01

The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given.

The Dutch Open Telescope: History, Status, Prospects

NARCIS (Netherlands)

Rutten, R.J.

1999-01-01

After many years of persistent telescope design and telescope construction, R.H. Hammerschlag has installed his Dutch Open Telescope (DOT) on La Palma. I brie y review its history and design. The future of optical solar physics at Utrecht hinges on a recently-funded three- year DOT science

A virtual reality environment for telescope operation

Science.gov (United States)

Martínez, Luis A.; Villarreal, José L.; Ángeles, Fernando; Bernal, Abel

2010-07-01

Astronomical observatories and telescopes are becoming increasingly large and complex systems, demanding to any potential user the acquirement of great amount of information previous to access them. At present, the most common way to overcome that information is through the implementation of larger graphical user interfaces and computer monitors to increase the display area. Tonantzintla Observatory has a 1-m telescope with a remote observing system. As a step forward in the improvement of the telescope software, we have designed a Virtual Reality (VR) environment that works as an extension of the remote system and allows us to operate the telescope. In this work we explore this alternative technology that is being suggested here as a software platform for the operation of the 1-m telescope.

LSST telescope and site status

Science.gov (United States)

Gressler, William J.

2016-07-01

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

Automatic Photoelectric Telescope Service

International Nuclear Information System (INIS)

Genet, R.M.; Boyd, L.J.; Kissell, K.E.; Crawford, D.L.; Hall, D.S.; BDM Corp., McLean, VA; Kitt Peak National Observatory, Tucson, AZ; Dyer Observatory, Nashville, TN)

1987-01-01

Automatic observatories have the potential of gathering sizable amounts of high-quality astronomical data at low cost. The Automatic Photoelectric Telescope Service (APT Service) has realized this potential and is routinely making photometric observations of a large number of variable stars. However, without observers to provide on-site monitoring, it was necessary to incorporate special quality checks into the operation of the APT Service at its multiple automatic telescope installation on Mount Hopkins. 18 references

The ATHENA telescope and optics status

Science.gov (United States)

Bavdaz, Marcos; Wille, Eric; Ayre, Mark; Ferreira, Ivo; Shortt, Brian; Fransen, Sebastiaan; Collon, Maximilien; Vacanti, Giuseppe; Barriere, Nicolas; Landgraf, Boris; Haneveld, Jeroen; van Baren, Coen; Zuknik, Karl-Heintz; Della Monica Ferreira, Desiree; Massahi, Sonny; Christensen, Finn; Krumrey, Michael; Burwitz, Vadim; Pareschi, Giovanni; Spiga, Daniele; Valsecchi, Giuseppe; Vernani, Dervis; Oliver, Paul; Seidel, André

2017-08-01

The work on the definition and technological preparation of the ATHENA (Advanced Telescope for High ENergy Astrophysics) mission continues to progress. In parallel to the study of the accommodation of the telescope, many aspects of the X-ray optics are being evolved further. The optics technology chosen for ATHENA is the Silicon Pore Optics (SPO), which hinges on technology spin-in from the semiconductor industry, and uses a modular approach to produce large effective area lightweight telescope optics with a good angular resolution. Both system studies and the technology developments are guided by ESA and implemented in industry, with participation of institutional partners. In this paper an overview of the current status of the telescope optics accommodation and technology development activities is provided.

Hard x-ray telescope mission

DEFF Research Database (Denmark)

Gorenstein, P.; Worrall, D.; Joensen, K.D.

1996-01-01

The Hard X-Ray Telescope was selected for study as a possible new intermediate size mission for the early 21st century. Its principal attributes are: (1) multiwavelength observing with a system of focussing telescopes that collectively observe from the UV to over 1 MeV, (2) much higher sensitivity...

Cryogenic and thermal design for the Space Infrared Telescope Facility (SIRTF)

Science.gov (United States)

Lee, J. H.; Brooks, W. F.

1984-01-01

The 1-meter class cryogenically cooled Space Infrared Telescope Facility (SIRTF) planned by NASA, is scheduled for a 1992 launch. SIRTF would be deployed from the Shuttle, and placed into a sun synchronous polar orbit of 700 km. The facility has been defined for a mission with a minimum initial lifetime of one year in orbit with mission extension that could be made possible through in-orbit servicing of the superfluid helium cryogenic system, and use of a thermal control system. The superfluid dewar would use an orbital disconnect system for the tank supports, and vapor cooling of the barrel baffle. The transient analysis of the design shows that the superfluid helium tank with no active feedback comes within temperature requirements for the nominal orbital aperture heat load, quiescent instrument, and chopper conditions.

21 CFR 886.5870 - Low-vision telescope.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Low-vision telescope. 886.5870 Section 886.5870...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5870 Low-vision telescope. (a) Identification. A low-vision telescope is a device that consists of an arrangement of lenses or mirrors intended for...

Time-resolved Polarimetry of the Superluminous SN 2015bn with the Nordic Optical Telescope

Energy Technology Data Exchange (ETDEWEB)

Leloudas, Giorgos; Gal-Yam, Avishay [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001 (Israel); Maund, Justyn R. [The Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Pursimo, Tapio [Nordic Optical Telescope, Apartado 474, E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Hsiao, Eric [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Malesani, Daniele; De Ugarte Postigo, Antonio [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen (Denmark); Patat, Ferdinando [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Sollerman, Jesper [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden); Stritzinger, Maximilian D. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Wheeler, J. Craig [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)

2017-03-01

We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between −20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs of spectropolarimetry are also available. Based on field stars, we determine the interstellar polarization in the Galaxy to be negligible. The polarization of SN 2015bn shows a statistically significant increase during the last epochs, confirming previous findings. Our well-sampled imaging polarimetry series allows us to determine that this increase (from ∼0.54% to ≳1.10%) coincides in time with rapid changes that took place in the optical spectrum. We conclude that the supernova underwent a “phase transition” at around +20 days, when the photospheric emission shifted from an outer layer, dominated by natal C and O, to a more aspherical inner core, dominated by freshly nucleosynthesized material. This two-layered model might account for the characteristic appearance and properties of Type I superluminous supernovae.

Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts

International Nuclear Information System (INIS)

Kaneda, K.; Misawa, H.; Tsuchiya, F.; Obara, T.; Iwai, K.; Katoh, Y.; Masuda, S.

2017-01-01

The polarization characteristics of zebra patterns (ZPs) in type IV solar bursts were studied. We analyzed 21 ZP events observed by the Assembly of Metric-band Aperture Telescope and Real-time Analysis System between 2010 and 2015 and identified the following characteristics: a degree of circular polarization (DCP) in the range of 0%–70%, a temporal delay of 0–70 ms between the two circularly polarized components (i.e., the right- and left-handed components), and dominant ordinary-mode emission in about 81% of the events. For most events, the relation between the dominant and delayed components could be interpreted in the framework of fundamental plasma emission and depolarization during propagation, though the values of DCP and delay were distributed across wide ranges. Furthermore, it was found that the DCP and delay were positively correlated (rank correlation coefficient R = 0.62). As a possible interpretation of this relationship, we considered a model based on depolarization due to reflections at sharp density boundaries assuming fundamental plasma emission. The model calculations of depolarization including multiple reflections and group delay during propagation in the inhomogeneous corona showed that the DCP and delay decreased as the number of reflections increased, which is consistent with the observational results. The dispersive polarization characteristics could be explained by the different numbers of reflections causing depolarization.

Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts

Energy Technology Data Exchange (ETDEWEB)

Kaneda, K.; Misawa, H.; Tsuchiya, F.; Obara, T. [Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Iwai, K. [National Institute of Information and Communications Technology, 4-2-1, Nukui-Kitamachi, Koganei, Tokyo 184-8795 (Japan); Katoh, Y. [Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Masuda, S., E-mail: k.kaneda@pparc.gp.tohoku.ac.jp [Institute for Space—Earth Environmental Research, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

2017-06-10

The polarization characteristics of zebra patterns (ZPs) in type IV solar bursts were studied. We analyzed 21 ZP events observed by the Assembly of Metric-band Aperture Telescope and Real-time Analysis System between 2010 and 2015 and identified the following characteristics: a degree of circular polarization (DCP) in the range of 0%–70%, a temporal delay of 0–70 ms between the two circularly polarized components (i.e., the right- and left-handed components), and dominant ordinary-mode emission in about 81% of the events. For most events, the relation between the dominant and delayed components could be interpreted in the framework of fundamental plasma emission and depolarization during propagation, though the values of DCP and delay were distributed across wide ranges. Furthermore, it was found that the DCP and delay were positively correlated (rank correlation coefficient R = 0.62). As a possible interpretation of this relationship, we considered a model based on depolarization due to reflections at sharp density boundaries assuming fundamental plasma emission. The model calculations of depolarization including multiple reflections and group delay during propagation in the inhomogeneous corona showed that the DCP and delay decreased as the number of reflections increased, which is consistent with the observational results. The dispersive polarization characteristics could be explained by the different numbers of reflections causing depolarization.

Scientific management of Space Telescope

Science.gov (United States)

Odell, C. R.

1981-01-01

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

Remote secure observing for the Faulkes Telescopes

Science.gov (United States)

Smith, Robert J.; Steele, Iain A.; Marchant, Jonathan M.; Fraser, Stephen N.; Mucke-Herzberg, Dorothea

2004-09-01

Since the Faulkes Telescopes are to be used by a wide variety of audiences, both powerful engineering level and simple graphical interfaces exist giving complete remote and robotic control of the telescope over the internet. Security is extremely important to protect the health of both humans and equipment. Data integrity must also be carefully guarded for images being delivered directly into the classroom. The adopted network architecture is described along with the variety of security and intrusion detection software. We use a combination of SSL, proxies, IPSec, and both Linux iptables and Cisco IOS firewalls to ensure only authenticated and safe commands are sent to the telescopes. With an eye to a possible future global network of robotic telescopes, the system implemented is capable of scaling linearly to any moderate (of order ten) number of telescopes.

Single particle detecting telescope system

International Nuclear Information System (INIS)

Yamamoto, I.; Tomiyama, T.; Iga, Y.; Komatsubara, T.; Kanada, M.; Yamashita, Y.; Wada, T.; Furukawa, S.

1981-01-01

We constructed the single particle detecting telescope system for detecting a fractionally charged particle. The telescope consists of position detecting counters, wall-less multi-cell chambers, single detecting circuits and microcomputer system as data I/0 processor. Especially, a frequency of double particle is compared the case of the single particle detecting with the case of an ordinary measurement

Building the Hubble Space Telescope

International Nuclear Information System (INIS)

O'dell, C.R.

1989-01-01

The development of the design for the Hubble Space Telescope (HST) is discussed. The HST optical system is described and illustrated. The financial and policy issues related to the development of the HST are considered. The actual construction of the HST optical telescope is examined. Also, consideration is given to the plans for the HST launch

Lee Sang Gak Telescope (LSGT): A Remotely Operated Robotic Telescope for Education and Research at Seoul National University

Science.gov (United States)

Im, Myungshin; Choi, Changsu; Kim, Kihyun

2015-08-01

We introduce the Lee Sang Gak Telescope (LSGT), a remotely operated, robotic 0.43-meter telescope. The telescope was installed at the Siding Spring Observatory, Australia, in 2014 October, to secure regular and exclusive access to the dark sky and excellent atmospheric conditions in the southern hemisphere from the Seoul National University (SNU) campus. Here, we describe the LSGT system and its performance, present example images from early observations, and discuss a future plan to upgrade the system. The use of the telescope includes (i) long-term monitoring observations of nearby galaxies, active galactic nuclei, and supernovae; (ii) rapid follow-up observations of transients such as gamma-ray bursts and gravitational wave sources; and (iii) observations for educational activities at SNU. Based on observations performed so far, we find that the telescope is capable of providing images to a depth of R=21.5 mag (point source detection) at 5-σ with 15 min total integration time under good obs-erving conditions.

HIGH-RESOLUTION LINEAR POLARIMETRIC IMAGING FOR THE EVENT HORIZON TELESCOPE

Energy Technology Data Exchange (ETDEWEB)

Chael, Andrew A.; Johnson, Michael D.; Narayan, Ramesh; Doeleman, Sheperd S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Wardle, John F. C. [Brandeis University, Physics Department, Waltham, MA 02454 (United States); Bouman, Katherine L., E-mail: achael@cfa.harvard.edu [Massachusetts Institute of Technology, Computer Science and Artificial Intelligence Laboratory, 32 Vassar Street, Cambridge, MA 02139 (United States)

2016-09-20

Images of the linear polarizations of synchrotron radiation around active galactic nuclei (AGNs) highlight their projected magnetic field lines and provide key data for understanding the physics of accretion and outflow from supermassive black holes. The highest-resolution polarimetric images of AGNs are produced with Very Long Baseline Interferometry (VLBI). Because VLBI incompletely samples the Fourier transform of the source image, any image reconstruction that fills in unmeasured spatial frequencies will not be unique and reconstruction algorithms are required. In this paper, we explore some extensions of the Maximum Entropy Method (MEM) to linear polarimetric VLBI imaging. In contrast to previous work, our polarimetric MEM algorithm combines a Stokes I imager that only uses bispectrum measurements that are immune to atmospheric phase corruption, with a joint Stokes Q and U imager that operates on robust polarimetric ratios. We demonstrate the effectiveness of our technique on 7 and 3 mm wavelength quasar observations from the VLBA and simulated 1.3 mm Event Horizon Telescope observations of Sgr A* and M87. Consistent with past studies, we find that polarimetric MEM can produce superior resolution compared to the standard CLEAN algorithm, when imaging smooth and compact source distributions. As an imaging framework, MEM is highly adaptable, allowing a range of constraints on polarization structure. Polarimetric MEM is thus an attractive choice for image reconstruction with the EHT.

Carbon Fiber Mirror for a CubeSat Telescope

Science.gov (United States)

Kim, Young-Soo; Jang, Jeong Gyun; Kim, Jihun; Nam, Uk Won

2017-08-01

Telescope mirrors made by carbon fibers have been increasingly used especially for space applications, and they may replace the traditional glass mirrors. Glass mirrors are easy to fabricate, but needed to be carefully handled as they are brittle. Other materials have also been considered for telescope mirrors, such as metals, plastics, and liquids even. However glass and glass ceramics are still commonly and dominantly used.Carbon fiber has mainly been used for mechanical supports like truss structure and telescope tubes, as it is stiff and light-weight. It can also be a good material for telescope mirrors, as it has additional merits of non-brittle and very low thermal expansion. Therefore, carbon fiber mirror would be suitable for space telescopes which should endure the harsh vibration conditions during launch.A light-weight telescope made by carbon fiber has been designed for a small satellite which would have much less weight than conventional ones. In this poster, mirror materials are reviewed, and a design of carbon fiber telescope is presented and discussed.

Optical and thermal design of 1.5-m aperture solar UV visible and IR observing telescope for Solar-C mission

Science.gov (United States)

Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.; Horiuchi, T.; Matsumoto, Y.; Takeyama, N.

2017-11-01

The next Japanese solar mission, SOLAR-C, which has been envisaged after successful science operation of Hinode (SOLAR-B) mission, is perusing two plans: plan-A and plan-B, and under extensive study from science objectives as well as engineering point of view. The plan-A aims at performing out-of-ecliptic observations for investigating, with helioseismic approach, internal structure and dynamo mechanisms of the Sun. It also explores polar regions where fast solar wind is believed to originate. A baseline orbit for plan-A is a circular orbit of 1 AU distance from the Sun with its inclination at around or greater than 40 degrees. The plan-B aims to study small-scale plasma processes and structures in the solar atmosphere which attract researchers' growing interest, followed by many Hinode discoveries [1], for understanding fully dynamism and magnetic nature of the atmosphere. With plan-B, high-angular-resolution investigation of the entire solar atmosphere (from the photosphere to the corona, including their interface layers, i.e., chromosphere and transition region) is to be performed with enhanced spectroscopic and spectro-polarimetric capability as compared with Hinode, together with enhanced sensitivity towards ultra-violet wavelengths. The orbit of plan-B is either a solar synchronous polar orbit of altitude around 600 km or a geosynchronous orbit to ensure continuous solar observations. After the decision of any one of the two plans, the SOLAR-C will be proposed for launch in mid-2010s. In this paper, we will present a basic design of one of major planned instrumental payload for the plan-B: the Solar Ultra-violet Visible and near IR observing Telescope (hereafter referred to as SUVIT). The basic concept in designing the SUVIT is to utilize as much as possible a heritage of successful telescope of the Solar Optical Telescope (SOT) aboard Hinode [2]. Major differences of SUVIT from SOT are the three times larger aperture of 1.5 m, which enables to collect one

A free market in telescope time?

Science.gov (United States)

Etherton, Jason; Steele, Iain A.; Mottram, Christopher J.

2004-09-01

As distributed systems are becoming more and more diverse in application there is a growing need for more intelligent resource scheduling. eSTAR Is a geographically distributed network of Grid-enabled telescopes, using grid middleware to provide telescope users with an authentication and authorisation method, allowing secure, remote access to such resources. The eSTAR paradigm is based upon this secure, single sign-on, giving astronomers or their agent proxies direct access to these telescopes. This concept, however, involves the complex issue of how to schedule observations stored within physically distributed media, on geographically distributed resources. This matter is complicated further by the varying degrees of constraints placed upon observations such as timeliness, atmospheric and meteorological conditions, and sky brightness to name a few. This paper discusses a free market approach to this scheduling problem, where astronomers are given credit, instead of time, from their respective TAGs to spend on telescopes as they see fit. This approach will ultimately provide a community-driven schedule, genuine indicators of the worth of specific telescope time and promote a more efficient use of that time, as well as demonstrating a 'survival of the fittest' type selection.

Polarization measurement for internal polarized gaseous targets

International Nuclear Information System (INIS)

Ye Zhenyu; Ye Yunxiu; Lv Haijiang; Mao Yajun

2004-01-01

The authors present an introduction to internal polarized gaseous targets, polarization method, polarization measurement method and procedure. To get the total nuclear polarization of hydrogen atoms (including the polarization of the recombined hydrogen molecules) in the target cell, authors have measured the parameters relating to atomic polarization and polarized hydrogen atoms and molecules. The total polarization of the target during our measurement is P T =0.853 ± 0.036. (authors)

Ground-Based Telescope Parametric Cost Model

Science.gov (United States)

Stahl, H. Philip; Rowell, Ginger Holmes

2004-01-01

A parametric cost model for ground-based telescopes is developed using multi-variable statistical analysis, The model includes both engineering and performance parameters. While diameter continues to be the dominant cost driver, other significant factors include primary mirror radius of curvature and diffraction limited wavelength. The model includes an explicit factor for primary mirror segmentation and/or duplication (i.e.. multi-telescope phased-array systems). Additionally, single variable models based on aperture diameter are derived. This analysis indicates that recent mirror technology advances have indeed reduced the historical telescope cost curve.

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

CERN Document Server

Pepin, M Barlow

2005-01-01

Commercially-made astronomical telescopes are better and less expensive than ever before, and their optical and mechanical performance can be superb. When a good-quality telescope fails to perform as well as it might, the reason is quite probably that it needs a little care and attention! Here is a 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. Here, too, are details of choosing new and used optics and accessories, along with enhancements you can make to extend their versatility and useful lifetime. This book is for you. Really. Looking after an astronomical telescope isn't only for the experts - although there are some things that only an expert should attempt - and every serious amateur astronomer will find invaluable information here, gleaned from ...

GRANITE- A steroscopic imaging Chernkov telescope system

International Nuclear Information System (INIS)

Shubnell, M.; Akerlof, C.W.; Cawley, M.F.; Chantell, M.; Fegan, D.J.; Fennell, S.; O'Flaherty, K.S.; Freeman, S.; Frishman, D.; Gaidos, J.A.; Hagan, J.; Harris, K.; Hillas, A.M.; Kerrick, A.D.; Lamb, R.C.; Lappin, T.; Lawrence, M.A.; Levy, H.; Lewis, D.A.; Meyer, D.I.; Mohanty, G.; Punch, M.; Reynolds, P.T.; Rovero, A.C.; Sembroski, G.; Weaverdyck, C.; Weekes, T.C.; Whitaker, T.; Wilson, C.

1993-01-01

A second 10 meter class imaging telescope was constructed on Mt. Hopkins, Arizona, the site of the original 10 meter Whipple Cherenkov telescope. The twin telescope system with a 140 meter base line will allow both a reduction in the energy threshold and an improvement in the rejection of the hardonic background. The new telescope started operation in December 1991. With the final completion of the first installation stage (GRANITE I) during spring 92, it is now operating simultaneously with the orginal reflector. We describe in this paper design and construction of the new instrument and demonstrate the capability of the experiment to record coincident events

Overdenture dengan Pegangan Telescopic Crown

Directory of Open Access Journals (Sweden)

Pambudi Santoso

2014-06-01

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

Trick or Treat and Telescopes

Science.gov (United States)

Buratti, Bonnie J.; Meinke, Bonnie K.; Schmude, Richard W.

2017-10-01

Based on an activity that DPS member Richard Schmude Jr. has been doing for years, with over 5000 children reached, DPS initiated in 2016 a pilot program entitled “Trick-or-Treat and Telescopes.” DPS encouraged its members to put out their telescopes during trick-or-treat time on Halloween, in their own lawns or in a neighbor’s lawn with better viewing (or more traffic). The program will be continued in 2017. This year should offer good viewing with a waxing gibbous moon and Saturn visible. The program was also advertised though the Night Sky Network, a consortium of astronomy clubs. The following website gives advice and connections to resources.https://dps.aas.org/education/trick-or-treat-and-telescopes acknowledged.

A decade of cost-reduction in very large telescopes - The SST as prototype of special-purpose telescopes

Science.gov (United States)

Smith, Harlan J.

1989-10-01

Many design and technical innovations over the past ten or fifteen years have reduced the costs of very large telescopes by nearly an order of magnitude over those of classical designs. Still a further order of magnitude reduction is possible if the telescope is specialized for on-axis spectroscopy, giving up especially the luxuries of wide field, multiple focal positions, and access to all the sky at will. The SST (Spectroscopic Survey Telescope) will use eighty-five 1-m circular mirrors mounted in a steel frame composed of hundreds of interlocking tetrahedrons, keeping a fixed elevation angle of 60 deg with rotation only in azimuth. Using an optical fiber it will feed as much light to spectrographs as can be done by a conventional 8-m telescope, yet has a target basic completion cost of only $6 million.

Performance of a continuously rotating half-wave plate on the POLARBEAR telescope

Energy Technology Data Exchange (ETDEWEB)

Takakura, Satoru [Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043 Japan (Japan); Aguilar, Mario [Departamento de Física, FCFM, Universidad de Chile, Blanco Encalada 2008, Santiago (Chile); Akiba, Yoshiki [SOKENDAI (The Graduate University for Advanced Studies), Hayama, Miura District, Kanagawa, 240-0115 Japan (Japan); Arnold, Kam; Elleflot, Tucker; Galitzki, Nicholas [Department of Physics, University of California, San Diego, CA, 92093-0424 (United States); Baccigalupi, Carlo [International School for Advanced Studies (SISSA), Via Bonomea 265, Trieste, I-34136 Italy (Italy); Barron, Darcy; Beckman, Shawn; Chinone, Yuji; Cukierman, Ari; Goeckner-Wald, Neil [Department of Physics, University of California, Berkeley, CA, 94720 (United States); Boettger, David [Centro de Astro-Ingeniería, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Santiago (Chile); Borrill, Julian [Computational Cosmology Center, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States); Chapman, Scott [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2 Canada (Canada); Ducout, Anne [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba, 277-8583 Japan (Japan); Errard, Josquin [Sorbonne Universités, Institut Lagrange de Paris (ILP), 98 bis Boulevard Arago, Paris, 75014 France (France); Fabbian, Giulio [Institut d' Astrophysique Spatiale, CNRS (UMR 8617), Université Paris-Sud, Université Paris-Saclay, bât. 121, Orsay, 91405 France (France); Fujino, Takuro, E-mail: takakura@vega.ess.sci.osaka-u.ac.jp [Yokohama National University, Yokohama, Kanagawa, 240-8501 Japan (Japan); and others

2017-05-01

A continuously rotating half-wave plate (CRHWP) is a promising tool to improve the sensitivity to large angular scales in cosmic microwave background (CMB) polarization measurements. With a CRHWP, single detectors can measure three of the Stokes parameters, I , Q and U , thereby avoiding the set of systematic errors that can be introduced by mismatches in the properties of orthogonal detector pairs. We focus on the implementation of CRHWPs in large aperture telescopes (i.e. the primary mirror is larger than the current maximum half-wave plate diameter of ∼0.5 m), where the CRHWP can be placed between the primary mirror and focal plane. In this configuration, one needs to address the intensity to polarization ( I → P ) leakage of the optics, which becomes a source of 1/f noise and also causes differential gain systematics that arise from CMB temperature fluctuations. In this paper, we present the performance of a CRHWP installed in the (\\scshape Polarbear) experiment, which employs a Gregorian telescope with a 2.5 m primary illumination pattern. The CRHWP is placed near the prime focus between the primary and secondary mirrors. We find that the I → P leakage is larger than the expectation from the physical properties of our primary mirror, resulting in a 1/f knee of 100 mHz. The excess leakage could be due to imperfections in the detector system, i.e. detector non-linearity in the responsivity and time-constant. We demonstrate, however, that by subtracting the leakage correlated with the intensity signal, the 1/f noise knee frequency is reduced to 32 mHz (ℓ ∼ 39 for our scan strategy), which is very promising to probe the primordial B-mode signal. We also discuss methods for further noise subtraction in future projects where the precise temperature control of instrumental components and the leakage reduction will play a key role.

The readout and control system of the mid-size telescope prototype of the Cherenkov telescope array

International Nuclear Information System (INIS)

Oya, I; Anguner, O; Birsin, E; Schwanke, U; Behera, B; Melkumyan, D; Schmidt, T; Sternberger, R; Wegner, P; Wiesand, S; Fuessling, M

2014-01-01

The Cherenkov Telescope Array (CTA) is one of the major ground-based astronomy projects being pursued and will be the largest facility for ground-based y-ray observations ever built. CTA will consist of two arrays: one in the Northern hemisphere composed of about 20 telescopes, and the other one in the Southern hemisphere composed of about 100 telescopes, both arrays containing telescopes of different type and size. A prototype for the Mid-Size Telescope (MST) with a diameter of 12 m has been installed in Berlin and is currently being commissioned. This prototype is composed of a mechanical structure, a drive system and mirror facets mounted with powered actuators to enable active control. Five Charge-Coupled Device (CCD) cameras, and a wide set of sensors allow the evaluation of the performance of the instrument. The design of the control software is following concepts and tools under evaluation within the CTA consortium in order to provide a realistic test-bed for the middleware: 1) The readout and control system for the MST prototype is implemented with the Atacama Large Millimeter/submillimeter Array (ALMA) Common Software (ACS) distributed control middleware; 2) the OPen Connectivity-Unified Architecture (OPC UA) is used for hardware access; 3) the document oriented MongoDB database is used for an efficient storage of CCD images, logging and alarm information: and 4) MySQL and MongoDB databases are used for archiving the slow control monitoring data and for storing the operation configuration parameters. In this contribution, the details of the implementation of the control system for the MST prototype telescope are described.

The readout and control system of the mid-size telescope prototype of the Cherenkov Telescope Array

Science.gov (United States)

Oya, I.; Anguner, O.; Behera, B.; Birsin, E.; Fuessling, M.; Melkumyan, D.; Schmidt, T.; Schwanke, U.; Sternberger, R.; Wegner, P.; Wiesand, S.; Cta Consortium,the

2014-06-01

The Cherenkov Telescope Array (CTA) is one of the major ground-based astronomy projects being pursued and will be the largest facility for ground-based y-ray observations ever built. CTA will consist of two arrays: one in the Northern hemisphere composed of about 20 telescopes, and the other one in the Southern hemisphere composed of about 100 telescopes, both arrays containing telescopes of different type and size. A prototype for the Mid-Size Telescope (MST) with a diameter of 12 m has been installed in Berlin and is currently being commissioned. This prototype is composed of a mechanical structure, a drive system and mirror facets mounted with powered actuators to enable active control. Five Charge-Coupled Device (CCD) cameras, and a wide set of sensors allow the evaluation of the performance of the instrument. The design of the control software is following concepts and tools under evaluation within the CTA consortium in order to provide a realistic test-bed for the middleware: 1) The readout and control system for the MST prototype is implemented with the Atacama Large Millimeter/submillimeter Array (ALMA) Common Software (ACS) distributed control middleware; 2) the OPen Connectivity-Unified Architecture (OPC UA) is used for hardware access; 3) the document oriented MongoDB database is used for an efficient storage of CCD images, logging and alarm information: and 4) MySQL and MongoDB databases are used for archiving the slow control monitoring data and for storing the operation configuration parameters. In this contribution, the details of the implementation of the control system for the MST prototype telescope are described.

Design and development of telescope control system and software for the 50/80 cm Schmidt telescope

Science.gov (United States)

Kumar, T. S.; Banavar, R. N.

2012-09-01

In this paper, we describe the details of telescope controller design for the 50/80 cm Schmidt telescope at the Aryabhatta Research Institute of observational sciencES. The GUI based software for commanding the telescope is developed in Visual C++. The hardware architecture features a distributed network of microcontrollers over CAN. The basic functionality can also be implemented using the dedicated RS232 port per board. The controller is able to perform with negligible rms velocity errors. At fine speeds limit cycles are exhibited due to nonlinear friction. At speeds over 3.90 × 10-02 radians/sec, the PI controller performs with peak errors less than 1%.

Simulation and track reconstruction for beam telescopes

CERN Document Server

Maqbool, Salman

2017-01-01

Beam telescopes are used for testing new detectors under development. Sensors are placed and a particle beam is passed through them. To test these novel detectors and determine their properties, the particle tracks need to be reconstructed from the known detectors in the telescope. Based on the reconstructed track, it’s predicted hits on the Device under Test (DUT) are compared with the actual hits on the DUT. Several methods exist for track reconstruction, but most of them don’t account for the effects of multiple scattering. General Broken Lines is one such algorithm which incorporates these effects during reconstruction. The aim of this project was to simulate the beam telescope and extend the track reconstruction framework for the FE-I4 telescope, which takes these effects into account. Section 1 introduces the problem, while section 2 focuses on beam telescopes. This is followed by the Allpix2 simulation framework in Section 3. And finally, Section 4 introduces the Proteus track reconstruction framew...

Habitable Exoplanet Imager Optical Telescope Concept Design

Science.gov (United States)

Stahl, H Philip

2017-01-01

The Habitable Exoplanet Imaging Mission (HabEx) is one of four missions under study for the 2020 Astrophysics Decadal Survey. Its goal is to directly image and spectroscopically characterize planetary systems in the habitable zone of Sun-like stars. Additionally, HabEx will perform a broad range of general astrophysics science enabled by 100 to 2500 nm spectral range and 3 x 3 arc-minute FOV. Critical to achieving the HabEx science goals is a large, ultra-stable UV/Optical/Near-IR (UVOIR) telescope. The baseline HabEx telescope is a 4-meter off-axis unobscured three-mirror-anastigmatic, diffraction limited at 400 nm with wavefront stability on the order of a few 10s of picometers. This paper summarizes the opto-mechanical design of the HabEx baseline optical telescope assembly, including a discussion of how science requirements drive the telescope's specifications, and presents analysis that the baseline telescope structure meets its specified tolerances.

Simulation and Track Reconstruction for Beam Telescopes

CERN Document Server

Maqbool, Salman

2017-01-01

Beam telescopes are an important tool to test new detectors under development in a particle beam. To test these novel detectors and determine their properties, the particle tracks need to be reconstructed from the known detectors in the telescope. Based on the reconstructed track, its predicted position on the Device under Test (DUT) are compared with the actual hits on the DUT. Several methods exist for track reconstruction, but most of them do not account for the effects of multiple scattering. General Broken Lines is one such algorithm which incorporates these effects during reconstruction. The aim of this project was to simulate the beam telescope and extend the track reconstruction framework for the FE-I4 telescope, which takes these effects into account. Section 1 introduces the problem, while section 2 focuses on beam telescopes. This is followed by the Allpix2 simulation framework in Section 3. And finally, Section 4 introduces the Proteus track reconstruction framework along with the General Broken ...

Habitable exoplanet imager optical telescope concept design

Science.gov (United States)

Stahl, H. Philip

2017-09-01

The Habitable Exoplanet Imaging Mission (HabEx) is one of four missions under study for the 2020 Astrophysics Decadal Survey. Its goal is to directly image and spectroscopically characterize planetary systems in the habitable zone of Sunlike stars. Additionally, HabEx will perform a broad range of general astrophysics science enabled by 100 to 2500 nm spectral range and 3 x 3 arc-minute FOV. Critical to achieving the HabEx science goals is a large, ultra-stable UV/Optical/Near-IR (UVOIR) telescope. The baseline HabEx telescope is a 4-meter off-axis unobscured three-mirroranastigmatic, diffraction limited at 400 nm with wavefront stability on the order of a few 10s of picometers. This paper summarizes the opto-mechanical design of the HabEx baseline optical telescope assembly, including a discussion of how science requirements drive the telescope's specifications, and presents analysis that the baseline telescope structure meets its specified tolerances.

Information and Communications Technology (ICT) Infrastructure for the ASTRI SST-2M telescope prototype for the Cherenkov Telescope Array

Science.gov (United States)

Gianotti, F.; Tacchini, A.; Leto, G.; Martinetti, E.; Bruno, P.; Bellassai, G.; Conforti, V.; Gallozzi, S.; Mastropietro, M.; Tanci, C.; Malaguti, G.; Trifoglio, M.

2016-08-01

The Cherenkov Telescope Array (CTA) represents the next generation of ground-based observatories for very high energy gamma-ray astronomy. The CTA will consist of two arrays at two different sites, one in the northern and one in the southern hemisphere. The current CTA design foresees, in the southern site, the installation of many tens of imaging atmospheric Cherenkov telescopes of three different classes, namely large, medium and small, so defined in relation to their mirror area; the northern hemisphere array would consist of few tens of the two larger telescope types. The Italian National Institute for Astrophysics (INAF) is developing the Cherenkov Small Size Telescope ASTRI SST- 2M end-to-end prototype telescope within the framework of the International Cherenkov Telescope Array (CTA) project. The ASTRI prototype has been installed at the INAF observing station located in Serra La Nave on Mt. Etna, Italy. Furthermore a mini-array, composed of nine of ASTRI telescopes, has been proposed to be installed at the Southern CTA site. Among the several different infrastructures belonging the ASTRI project, the Information and Communication Technology (ICT) equipment is dedicated to operations of computing and data storage, as well as the control of the entire telescope, and it is designed to achieve the maximum efficiency for all performance requirements. Thus a complete and stand-alone computer centre has been designed and implemented. The goal is to obtain optimal ICT equipment, with an adequate level of redundancy, that might be scaled up for the ASTRI mini-array, taking into account the necessary control, monitor and alarm system requirements. In this contribution we present the ICT equipment currently installed at the Serra La Nave observing station where the ASTRI SST-2M prototype will be operated. The computer centre and the control room are described with particular emphasis on the Local Area Network scheme, the computing and data storage system, and the

Space Telescope maintenance and refurbishment

Science.gov (United States)

Trucks, H. F.

1983-01-01

The Space Telescope (ST) represents a new concept regarding spaceborne astronomical observatories. Maintenance crews will be brought to the orbital worksite to make repairs and replace scientific instruments. For major overhauls the telescope can be temporarily returned to earth with the aid of the Shuttle. It will, thus, be possible to conduct astronomical studies with the ST for two decades or more. The five first-generation scientific instruments used with the ST include a wide field/planetary camera, a faint object camera, a faint object spectrograph, a high resolution spectrograph, and a high speed photometer. Attention is given to the optical telescope assembly, the support systems module, aspects of mission and science operations, unscheduled maintenance, contingency orbital maintenance, planned on-orbit maintenance, ground maintenance, ground refurbishment, and ground logistics.

Eyes on the sky a spectrum of telescopes

CERN Document Server

Graham-Smith, Francis

2016-01-01

Astronomy is experiencing a golden age, with a new generation of innovative telescopes yielding a flood of information on the Universe. This book traces the development of telescopes from Galileo to the present day, and explains the basic principles of telescopes that operate in different parts of electromagnetic spectrum.

Optical Design for a Survey X-Ray Telescope

Science.gov (United States)

Saha, Timo T.; Zhang, William W.; McClelland, Ryan S.

2014-01-01

Optical design trades are underway at the Goddard Space Flight Center to define a telescope for an x-ray survey mission. Top-level science objectives of the mission include the study of x-ray transients, surveying and long-term monitoring of compact objects in nearby galaxies, as well as both deep and wide-field x-ray surveys. In this paper we consider Wolter, Wolter-Schwarzschild, and modified Wolter-Schwarzschild telescope designs as basic building blocks for the tightly nested survey telescope. Design principles and dominating aberrations of individual telescopes and nested telescopes are discussed and we compare the off-axis optical performance at 1.0 KeV and 4.0 KeV across a 1.0-degree full field-of-view.

ANTARES : The first undersea neutrino telescope

NARCIS (Netherlands)

Ageron, M.; Aguilar, J. A.; Al Samarai, I.; Albert, A.; Ameli, F.; Andre, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Arnaud, K.; Aslanides, E.; Jesus, A. C. Assis; Astraatmadja, T.; Aubert, J. -J.; Auer, R.; Barbarito, E.; Baret, B.; Basa, S.; Bazzotti, M.; Becherini, Y.; Beltramelli, J.; Bersani, A.; Bertin, V.; Beurthey, S.; Biagi, S.; Bigongiari, C.; Billault, M.; Blaes, R.; Bogazzi, C.; de Botton, N.; Bou-Cabo, M.; Boudahef, B.; Bouwhuis, M. C.; Brown, A. M.; Brunner, J.; Busto, J.; Caillat, L.; Calzas, A.; Camarena, F.; Capone, A.; Caponetto, L.; Carloganu, C.; Carminati, G.; Carmona, E.; Carr, J.; Carton, P. H.; Cassano, B.; Castorina, E.; Cecchini, S.; Ceres, A.; Chaleil, Th; Charvis, Ph; Chauchot, P.; Chiarusi, T.; Circella, M.; Compere, C.; Coniglione, R.; Coppolani, X.; Cosquer, A.; Costantini, H.; Cottini, N.; Coyle, P.; Cuneo, S.; Curtil, C.; D'Amato, C.; Damy, G.; van Dantzig, R.; De Bonis, G.; Decock, G.; Decowski, M. P.; Dekeyser, I.; Delagnes, E.; Desages-Ardellier, F.; Deschamps, A.; Destelle, J. -J.; Di Maria, F.; Dinkespiler, B.; Distefano, C.; Dominique, J. -L.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drogou, J. -F.; Drouhin, D.; Druillole, F.; Durand, D.; Durand, R.; Eberl, T.; Emanuele, U.; Engelen, J. J.; Ernenwein, J. -P.; Escoffier, S.; Falchini, E.; Favard, S.; Fehr, F.; Feinstein, F.; Ferri, M.; Ferry, S.; Fiorello, C.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J. -L.; Galata, S.; Galeotti, S.; Gay, P.; Gensolen, F.; Giacomelli, G.; Gojak, C.; Gomez-Gonzalez, J. P.; Goret, Ph.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Hartmann, B.; Heijboer, A. J.; Heine, E.; Hello, Y.; Henry, S.; Hernandez-Rey, J. J.; Herold, B.; Hoessl, J.; Hogenbirk, J.; Hsu, C. C.; Hubbard, J. R.; Jaquet, M.; Jaspers, M.; de Jong, M.; Jourde, D.; Kadler, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Karg, T.; Karkar, S.; Karolak, M.; Katz, U.; Keller, P.; Kestener, P.; Kok, E.; Kok, H.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Kruijer, A.; Kuch, S.; Kulikovskiy, V.; Lachartre, D.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lahonde-Hamdoun, C.; Lamare, P.; Lambard, G.; Languillat, J-C; Larosa, G.; Lavalle, J.; Le Guen, Y.; Le Provost, H.; LeVanSuu, A.; Lefevre, D.; Legou, T.; Lelaizant, G.; Leveque, C.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Lyashuk, V.; Magnier, P.; Mangano, S.; Marcel, A.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Masullo, R.; Mazeas, F.; Mazure, A.; Meli, A.; Melissas, M.; Migneco, E.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Neff, M.; Niess, V.; Nooren, G. J. L.; Oberski, J. E. J.; Olivetto, C.; Palanque-Delabrouille, N.; Patioselitis, D.; Papaleo, R.; Pavalas, G. E.; Payet, K.; Payre, P.; Peek, H.; Petrovic, J.; Piattelli, P.; Picot-Clemente, N.; Picq, C.; Piret, Y.; Poinsignon, J.; Popa, V.; Pradier, T.; Presani, E.; Prono, G.; Racca, C.; Raia, G.; van Randwijk, J.; Real, D.; Reed, C.; Rethore, F.; Rewiersma, P.; Riccobene, G.; Richardt, C.; Richter, R.; Ricol, J. S.; Rigaud, V.; Roca, V.; Roensch, K.; Rolin, J. -F.; Rostovtsev, A.; Rottura, A.; Roux, J.; Rujoiu, M.; Ruppi, M.; Russo, G. V.; Salesa, F.; Salomon, K.; Sapienza, P.; Schmitt, F.; Schoeck, F.; Schuller, J. -P.; Schuessler, F.; Sciliberto, D.; Shanidze, R.; Shirokov, E.; Simeone, F.; Sottoriva, A.; Spies, A.; Spona, T.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th; Streeb, K.; Sulak, L.; Taiuti, M.; Tamburini, C.; Tao, C.; Tasca, L.; Terreni, G.; Tezier, D.; Toscano, S.; Urbano, F.; Valdy, P.; Vallage, B.; Van Elewyck, V.; Vannoni, G.; Vecchi, M.; Venekamp, G.; Verlaat, B.; Vernin, P.; Virique, E.; de Vries, G.; Wijnker, G.; Wobbe, G.; de Wolf, E.; Yakovenko, Y.; Yepes, H.; Zaborov, D.; Zaccone, H.; Zornoza, J. D.; Zuniga, J.; van Wijk, R.

2011-01-01

The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the

The EMIR multi-band mm-wave receiver for the IRAM 30-m telescope

Science.gov (United States)

Carter, M.; Lazareff, B.; Maier, D.; Chenu, J.-Y.; Fontana, A.-L.; Bortolotti, Y.; Boucher, C.; Navarrini, A.; Blanchet, S.; Greve, A.; John, D.; Kramer, C.; Morel, F.; Navarro, S.; Peñalver, J.; Schuster, K. F.; Thum, C.

2012-02-01

Aims: The prime motivation of this project was to design and build a state-of-art mm-wave heterodyne receiver system to enhance the observing throughput of the IRAM 30-m radiotelescope. More specifically, the requirements were i) state-of-art noise performance for spectroscopic observations; ii) simultaneous dual polarization and dual-frequency observing; iii) coverage of the atmospheric transmission windows from 83 to 360 GHz; iv) compact footprint and minimal maintenance. Methods: Key elements for low noise performance of heterodyne mixers are the superconducting Niobium junctions, operating at ≃4 K. These junctions are embedded in carefully designed coupling structures; furthermore, since atmospheric radiation is a significant contributor to the system noise budget, all mixers are either sideband separating or sideband rejecting. To achieve low noise, it is also essential to maximize the coupling of the receiver to the astronomical source, and to minimize the coupling to thermal radiation from the ground-based environment; this is achieved through mirror optics that realize a wavelength-independent coupling to the telescope. A flexible configuration of mirrors and frequency selective surfaces permits various combinations of frequency bands, as well as dual-load radiometric calibration. Low noise intermediate frequency amplifiers and bias electronics also play an important role in the system performance. Results: The EMIR receiver in operation at the 30 m telescope offers four frequency bands: B1: 83-117 GHz, B2: 129-174 GHz, B3: 200-267 GHz, and B4: 260-360 GHz. In each band, the two orthogonal polarizations are observed simultaneously. Dual-band combinations B1/2 B1/3, and B2/4 are available. Bands 1 and 4 (also 3 as of Nov.-2011) feature sideband separation. In dual-band configuration, including sideband separation and polarization diplexing, up to eight IF channels are delivered to the spectrometers, totaling up to 64 GHz of signal bandwidth (of which 32

Survey Strategy Optimization for the Atacama Cosmology Telescope

Science.gov (United States)

De Bernardis, F.; Stevens, J. R.; Hasselfield, M.; Alonso, D.; Bond, J. R.; Calabrese, E.; Choi, S. K.; Crowley, K. T.; Devlin, M.; Wollack, E. J.

2016-01-01

In recent years there have been significant improvements in the sensitivity and the angular resolution of the instruments dedicated to the observation of the Cosmic Microwave Background (CMB). ACTPol is the first polarization receiver for the Atacama Cosmology Telescope (ACT) and is observing the CMB sky with arcmin resolution over approximately 2000 square degrees. Its upgrade, Advanced ACTPol (AdvACT), will observe the CMB in five frequency bands and over a larger area of the sky. We describe the optimization and implementation of the ACTPol and AdvACT surveys. The selection of the observed fields is driven mainly by the science goals, that is, small angular scale CMB measurements, B-mode measurements and cross-correlation studies. For the ACTPol survey we have observed patches of the southern galactic sky with low galactic foreground emissions which were also chosen to maximize the overlap with several galaxy surveys to allow unique cross-correlation studies. A wider field in the northern galactic cap ensured significant additional overlap with the BOSS spectroscopic survey. The exact shapes and footprints of the fields were optimized to achieve uniform coverage and to obtain cross-linked maps by observing the fields with different scan directions. We have maximized the efficiency of the survey by implementing a close to 24-hour observing strategy, switching between daytime and nighttime observing plans and minimizing the telescope idle time. We describe the challenges represented by the survey optimization for the significantly wider area observed by AdvACT, which will observe roughly half of the low-foreground sky. The survey strategies described here may prove useful for planning future ground-based CMB surveys, such as the Simons Observatory and CMB Stage IV surveys.

EUSO-TA prototype telescope

Energy Technology Data Exchange (ETDEWEB)

Bisconti, Francesca, E-mail: francesca.bisconti@kit.edu

2016-07-11

EUSO-TA is one of the prototypes developed for the JEM-EUSO project, a space-based large field-of-view telescope to observe the fluorescence light emitted by cosmic ray air showers in the atmosphere. EUSO-TA is a ground-based prototype located at the Telescope Array (TA) site in Utah, USA, where an Electron Light Source and a Central Laser Facility are installed. The purpose of the EUSO-TA project is to calibrate the prototype with the TA fluorescence detector in presence of well-known light sources and cosmic ray air showers. In 2015, the detector started the first measurements and tests using the mentioned light sources have been performed successfully. A first cosmic ray candidate has been observed, as well as stars of different magnitude and color index. Since Silicon Photo-Multipliers (SiPMs) are very promising for fluorescence telescopes of next generation, they are under consideration for the realization of a new prototype of EUSO Photo Detector Module (PDM). The response of this sensor type is under investigation through simulations and laboratory experimentation.

EUSO-TA prototype telescope

Science.gov (United States)

Bisconti, Francesca; JEM-EUSO Collaboration

2016-07-01

EUSO-TA is one of the prototypes developed for the JEM-EUSO project, a space-based large field-of-view telescope to observe the fluorescence light emitted by cosmic ray air showers in the atmosphere. EUSO-TA is a ground-based prototype located at the Telescope Array (TA) site in Utah, USA, where an Electron Light Source and a Central Laser Facility are installed. The purpose of the EUSO-TA project is to calibrate the prototype with the TA fluorescence detector in presence of well-known light sources and cosmic ray air showers. In 2015, the detector started the first measurements and tests using the mentioned light sources have been performed successfully. A first cosmic ray candidate has been observed, as well as stars of different magnitude and color index. Since Silicon Photo-Multipliers (SiPMs) are very promising for fluorescence telescopes of next generation, they are under consideration for the realization of a new prototype of EUSO Photo Detector Module (PDM). The response of this sensor type is under investigation through simulations and laboratory experimentation.

Development of the quality control system of the readout electronics for the large size telescope of the Cherenkov Telescope Array observatory

Science.gov (United States)

Konno, Y.; Kubo, H.; Masuda, S.; Paoletti, R.; Poulios, S.; Rugliancich, A.; Saito, T.

2016-07-01

The Cherenkov Telescope Array (CTA) is the next generation VHE γ-ray observatory which will improve the currently available sensitivity by a factor of 10 in the range 100 GeV to 10 TeV. The array consists of different types of telescopes, called large size telescope (LST), medium size telescope (MST) and small size telescope (SST). A LST prototype is currently being built and will be installed at the Observatorio Roque de los Muchachos, island of La Palma, Canary islands, Spain. The readout system for the LST prototype has been designed and around 300 readout boards will be produced in the coming months. In this note we describe an automated quality control system able to measure basic performance parameters and quickly identify faulty boards.

MAPPING THE POLARIZATION OF THE RADIO-LOUD Ly α NEBULA B3 J2330+3927

International Nuclear Information System (INIS)

You, Chang; Zabludoff, Ann; Smith, Paul; Jannuzi, Buell; Yang, Yujin; Kim, Eunchong; Lee, Myung Gyoon; Prescott, Moire K. M.; Matsuda, Yuichi

2017-01-01

Ly α nebulae, or “Ly α blobs,” are extended (up to ∼100 kpc), bright (L Lyα  ≳ 10 43 erg s −1 ) clouds of Ly α emitting gas that tend to lie in overdense regions at z  ∼ 2–5. The origin of the Ly α emission remains unknown, but recent theoretical work suggests that measuring the polarization might discriminate among powering mechanisms. Here we present the first narrowband imaging polarimetry of a radio-loud Ly α nebula, B3 J2330+3927, at z = 3.09, with an embedded active galactic nucleus (AGN). The AGN lies near the blob’s Ly α emission peak, and its radio lobes align roughly with the blob’s major axis. With the SPOL polarimeter on the 6.5 m MMT telescope, we map the total (Ly α + continuum) polarization in a grid of circular apertures of a radius of 0.″6 (4.4 kpc), detecting a significant (>2 σ ) polarization fraction P % in nine apertures and achieving strong upper limits (as low as 2%) elsewhere. P % increases from <2% at ∼5 kpc from the blob center to 17% at ∼15–25 kpc. The detections are distributed asymmetrically, roughly along the nebula’s major axis. The polarization angles θ are mostly perpendicular to this axis. Comparing the Ly α flux to that of the continuum and conservatively assuming that the continuum is highly polarized (20%–100%) and aligned with the total polarization, we place lower limits on the polarization of the Ly α emission P %,Lyα ranging from no significant polarization at ∼5 kpc from the blob center to 3%–17% at 10–25 kpc. Like the total polarization, the Ly α polarization detections occur more often along the blob’s major axis.

EDUCATIONAL ASTRONOMICAL OBSERVATIONS ON REMOTE ACCESS TELESCOPES

Directory of Open Access Journals (Sweden)

Ivan P. Kriachko

2016-01-01

Full Text Available The purpose of this article is to show the way of overcoming one of the major problems of astronomy teaching methods in upper secondary school – organization of educational astronomical observations. Nowadays it became possible to perform such observations on remote access telescopes. By using up-to-date informational and communicational technologies, having an opportunity to work with robotic telescopes allows us to organize a unique cognitive and research oriented activities for students while conducting their specialized astronomical studies. Below here is given a brief description of the most significant robotic telescopes and the way of the usage of open remote access telescopic network which was created by professors and scientists of Harvard-Smithsonian Center for Astrophysics, USA.

Polarized triton scattering from 26Mg, 27Al and 28Si at 17 MeV

International Nuclear Information System (INIS)

Hardekopf, R.A.; Brown, R.E.; Correll, F.D.; Ohlsen, G.G.

1980-01-01

Differential-cross-section and analyzing-power angular distributions were measured for 17 MeV tritons elastically scattered from targets of 26 Mg, 27 Al, and 28 Si in the angular range 20 to 160 0 . The experiment was performed at the Los Alamos Scientific Laboratory Van de Graaff facility using the Lamb-shift polarized triton source and the supercube scattering chamber. A pair of detector telescopes with angular resolutions of +-0.4 0 detected the reaction products, with mass identification and storage performed by an on-line computer. The triton beam intensity available at the target was about 70 nA with a polarization of 0.77. The target thicknesses were about 3 mg/cm 2 , although thinner targets were used for the 27 Al forward-angle data

Optimization of Transition Edge Sensor Arrays for Cosmic Microwave Background Observations With the South Pole Telescope

Energy Technology Data Exchange (ETDEWEB)

Ding, Junjia; Ade, P. A. R.; Anderson, A. J.; Avva, J.; Ahmed, Z.; Arnold, K.; Austermann, J. E.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Byrum, K.; Carlstrom, J. E.; Carter, F. W.; Chang, C. L.; Cho, H. M.; Cliche, J. F.; Cukierman, A.; Czaplewski, D.; Divan, R.; de Haan, T.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Gilbert, A.; Gannon, R.; Guyser, R.; Halverson, N. W.; Harrington, N. L.; Hattori, K.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Hubmayr, J.; Huang, N.; Irwin, K. D.; Jeong, O.; Khaire, T.; Kubik, D.; Kuo, C. L.; Lee, A. T.; Leitch, E. M.; Meyer, S. S.; Miller, C. S.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Novosad, V.; Padin, S.; Pan, Z.; Pearson, J.; Posada, C. M.; Rahlin, A.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Shariff, J. A.; Shirley, I.; Shirokoff, E.; Smecher, G.; Sobrin, J.; Stan, L.; Stark, A. A.; Story, K.; Suzuki, A.; Tang, Q. Y.; Thakur, R. B.; Thompson, K. L.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Wu, W. L. K.; Yefremenko, V.; Yoon, K. W.

2017-06-01

In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South PoleTelescope. The camera, which contains similar to 16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs.

Development of a SiPM Camera for a Schwarzschild-Couder Cherenkov Telescope for the Cherenkov Telescope Array

CERN Document Server

Otte, A N; Dickinson, H.; Funk, S.; Jogler, T.; Johnson, C.A.; Karn, P.; Meagher, K.; Naoya, H.; Nguyen, T.; Okumura, A.; Santander, M.; Sapozhnikov, L.; Stier, A.; Tajima, H.; Tibaldo, L.; Vandenbroucke, J.; Wakely, S.; Weinstein, A.; Williams, D.A.

2015-01-01

We present the development of a novel 11328 pixel silicon photomultiplier (SiPM) camera for use with a ground-based Cherenkov telescope with Schwarzschild-Couder optics as a possible medium-sized telescope for the Cherenkov Telescope Array (CTA). The finely pixelated camera samples air-shower images with more than twice the optical resolution of cameras that are used in current Cherenkov telescopes. Advantages of the higher resolution will be a better event reconstruction yielding improved background suppression and angular resolution of the reconstructed gamma-ray events, which is crucial in morphology studies of, for example, Galactic particle accelerators and the search for gamma-ray halos around extragalactic sources. Packing such a large number of pixels into an area of only half a square meter and having a fast readout directly attached to the back of the sensors is a challenging task. For the prototype camera development, SiPMs from Hamamatsu with through silicon via (TSV) technology are used. We give ...

The Falcon Telescope Network

Science.gov (United States)

Chun, F.; Tippets, R.; Dearborn, M.; Gresham, K.; Freckleton, R.; Douglas, M.

2014-09-01

The Falcon Telescope Network (FTN) is a global network of small aperture telescopes developed by the Center for Space Situational Awareness Research in the Department of Physics at the United States Air Force Academy (USAFA). Consisting of commercially available equipment, the FTN is a collaborative effort between USAFA and other educational institutions ranging from two- and four-year colleges to major research universities. USAFA provides the equipment (e.g. telescope, mount, camera, filter wheel, dome, weather station, computers and storage devices) while the educational partners provide the building and infrastructure to support an observatory. The user base includes USAFA along with K-12 and higher education faculty and students. Since the FTN has a general use purpose, objects of interest include satellites, astronomical research, and STEM support images. The raw imagery, all in the public domain, will be accessible to FTN partners and will be archived at USAFA in the Cadet Space Operations Center. FTN users will be able to submit observational requests via a web interface. The requests will then be prioritized based on the type of user, the object of interest, and a user-defined priority. A network wide schedule will be developed every 24 hours and each FTN site will autonomously execute its portion of the schedule. After an observational request is completed, the FTN user will receive notification of collection and a link to the data. The Falcon Telescope Network is an ambitious endeavor, but demonstrates the cooperation that can be achieved by multiple educational institutions.

The next generation balloon-borne large aperture submillimeter telescope (BLAST-TNG)

Science.gov (United States)

Dober, Bradley Jerald

Large areas of astrophysics, such as precision cosmology, have benefited greatly from large maps and datasets, yielded by telescopes of ever-increasing number and ability. However, due to the unique challenges posed by submillimeter polarimetry, the study of molecular cloud dynamics and star formation remain stunted. Previously, polarimetry data was limited to a few vectors on only the brightest areas of molecular clouds. This made drawing statistically-driven conclusions a daunting task. However, the successful flight of the Balloon-born Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) generated maps with thousands of independent polarization measurements of molecular clouds, and ushered in a new era of empirical modeling of molecular cloud dynamics. Now that the potential benefits from large-scale maps of magnetic fields in molecular clouds had been identified, a successor that would truly unlock the secrets must be born. The Next Generation Balloon-borne Large Aperture Submillimeter Telescope (BLAST-TNG), the successor to BLASTPol, has the ability to make larger and more detailed maps of magnetic fields in molecular clouds. It will push the field of star formation into a statistics-driven, empirical realm. With these large, detailed datasets, astronomers will be able to find new relationships between the dust dynamics and the magnetic fields. The field will surge to a new level of understanding. One of the key enabling technologies of BLAST-TNG is its three arrays of polarization-sensitive Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are superconducting RLC circuits with a resonant frequency that shifts proportionally to the amount of incident radiation. The key feature of MKIDs is that thousands of detectors, each with their own unique resonant frequency, can be coupled to the same readout line. This technology will be able to drive the production of large-scale monolithic arrays, containing tens or hundreds of thousands of detectors

Processing of data from innovative parabolic strip telescope.

Science.gov (United States)

Kosejk, Vladislav; Novy, J.; Chadzitaskos, Goce

2015-12-01

This paper presents an innovative telescope design based on the usage of a parabolic strip fulfilling the function of an objective. Isaac Newton was the first to solve the problem of chromatic aberration, which is caused by a difference in the refractive index of lenses. This problem was solved by a new kind of telescope with a mirror used as an objective. There are many different kinds of telescopes. The most basic one is the lens telescope. This type of a telescope uses a set of lenses. Another type is the mirror telescope, which employs the concave mirror, spherical parabolic mirror or hyperbolically shaped mirror as its objective. The lens speed depends directly on the surface of a mirror. Both types can be combined to form a telescope composed of at least two mirrors and a set of lenses. The light is reflected from the primary mirror to the secondary one and then to the lens system. This type is smaller-sized, with a respectively reduced lens speed. The telescope design presented in this paper uses a parabolic strip fulfilling the function of an objective. Observed objects are projected as lines in a picture plane. Each of the lines of a size equal to the size of the strip corresponds to the sum of intensities of the light coming perpendicular to the objective from an observed object. A series of pictures taken with a different rotation and processed by a special reconstruction algorithm is needed to get 2D pictures. The telescope can also be used for fast detection of objects. In this mode, the rotation and multiple pictures are not needed, just one picture in the focus of a mirror is required to be taken.

Polarized Redundant-Baseline Calibration for 21 cm Cosmology Without Adding Spectral Structure

Science.gov (United States)

Dillon, Joshua S.; Kohn, Saul A.; Parsons, Aaron R.; Aguirre, James E.; Ali, Zaki S.; Bernardi, Gianni; Kern, Nicholas S.; Li, Wenyang; Liu, Adrian; Nunhokee, Chuneeta D.; Pober, Jonathan C.

2018-04-01

21 cm cosmology is a promising new probe of the evolution of visible matter in our universe, especially during the poorly-constrained Cosmic Dawn and Epoch of Reionization. However, in order to separate the 21 cm signal from bright astrophysical foregrounds, we need an exquisite understanding of our telescopes so as to avoid adding spectral structure to spectrally-smooth foregrounds. One powerful calibration method relies on repeated simultaneous measurements of the same interferometric baseline to solve for the sky signal and for instrumental parameters simultaneously. However, certain degrees of freedom are not constrained by asserting internal consistency between redundant measurements. In this paper, we review the origin of these degeneracies of redundant-baseline calibration and demonstrate how they can source unwanted spectral structure in our measurement and show how to eliminate that additional, artificial structure. We also generalize redundant calibration to dual-polarization instruments, derive the degeneracy structure, and explore the unique challenges to calibration and preserving spectral smoothness presented by a polarized measurement.

First Polarized Power Spectra from HERA-19 Commissioning Data: Comparison with Simulations

Science.gov (United States)

Igarashi, Amy; Chichura, Paul; Fox Fortino, Austin; Kohn, Saul; Aguirre, James; HERA Collaboration, CHAMP

2018-01-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope whose primary goal is the detection of redshifted 21-cm line radiation produced from the spin-flip transition of HI during the Epoch of Reionization (EoR). HERA is currently under construction in South Africa, and will eventually be an array of 350 14-m antennas. HERA aims for a statistical detection of the power spectrum of this emission, using the so-called delay spectrum technique (Parsons et al 2012). We examine a first season of commissioning data from the first 19 elements (HERA-19) to characterize Galactic and extragalactic foregrounds. We compare the delay spectrum for HERA-19 constructed from data to those constructed from simulations done using a detailed instrument electromagnetic model and using the unpolarized Global Sky Model (GSM2008). We compare the data and simulations to explore the effects of Stokes-I to Q and U leakage, and further examine whether statistical models of polarization match the observed polarized power spectra.

Development of the quality control system of the readout electronics for the large size telescope of the Cherenkov Telescope Array observatory

Energy Technology Data Exchange (ETDEWEB)

Konno, Y.; Kubo, H.; Masuda, S. [Department of Physics, Graduate School of Science, Kyoto University, Kyoto (Japan); Paoletti, R.; Poulios, S. [SFTA Department, Physics Section, University of Siena and INFN, Siena (Italy); Rugliancich, A., E-mail: andrea.rugliancich@pi.infn.it [SFTA Department, Physics Section, University of Siena and INFN, Siena (Italy); Saito, T. [Department of Physics, Graduate School of Science, Kyoto University, Kyoto (Japan)

2016-07-11

The Cherenkov Telescope Array (CTA) is the next generation VHE γ-ray observatory which will improve the currently available sensitivity by a factor of 10 in the range 100 GeV to 10 TeV. The array consists of different types of telescopes, called large size telescope (LST), medium size telescope (MST) and small size telescope (SST). A LST prototype is currently being built and will be installed at the Observatorio Roque de los Muchachos, island of La Palma, Canary islands, Spain. The readout system for the LST prototype has been designed and around 300 readout boards will be produced in the coming months. In this note we describe an automated quality control system able to measure basic performance parameters and quickly identify faulty boards. - Highlights: • The Dragon Board is part of the DAQ of the LST Cherenkov telescope prototype. • We developed an automated quality control system for the Dragon Board. • We check pedestal, linearity, pulse shape and crosstalk values. • The quality control test can be performed on the production line.

VLTI auxiliary telescopes: a full object-oriented approach

Science.gov (United States)

Chiozzi, Gianluca; Duhoux, Philippe; Karban, Robert

2000-06-01

The Very Large Telescope (VLT) Telescope Control Software (TCS) is a portable system. It is now in use or will be used in a whole family of ESO telescopes VLT Unit Telescopes, VLTI Auxiliary Telescopes, NTT, La Silla 3.6, VLT Survey Telescope and Astronomical Site Monitors in Paranal and La Silla). Although it has been developed making extensive usage of Object Oriented (OO) methodologies, the overall development process chosen at the beginning of the project used traditional methods. In order to warranty a longer lifetime to the system (improving documentation and maintainability) and to prepare for future projects, we have introduced a full OO process. We have taken as a basis the United Software Development Process with the Unified Modeling Language (UML) and we have adapted the process to our specific needs. This paper describes how the process has been applied to the VLTI Auxiliary Telescopes Control Software (ATCS). The ATCS is based on the portable VLT TCS, but some subsystems are new or have specific characteristics. The complete process has been applied to the new subsystems, while reused code has been integrated in the UML models. We have used the ATCS on one side to tune the process and train the team members and on the other side to provide a UML and WWW based documentation for the portable VLT TCS.

The TACTIC atmospheric Cherenkov imaging telescope

International Nuclear Information System (INIS)

Koul, R.; Tickoo, A.K.; Kaul, S.K.; Kaul, S.R.; Kumar, N.; Yadav, K.K.; Bhatt, N.; Venugopal, K.; Goyal, H.C.; Kothari, M.; Chandra, P.; Rannot, R.C.; Dhar, V.K.; Koul, M.K.; Kaul, R.K.; Kotwal, S.; Chanchalani, K.; Thoudam, S.; Chouhan, N.; Sharma, M.; Bhattacharyya, S.; Sahayanathan, S.

2007-01-01

The TACTIC (TeV Atomospheric Cherenkov Telescope with Imaging Camera) γ-ray telescope, equipped with a light collector of area ∼9.5m 2 and a medium resolution imaging camera of 349 pixels, has been in operation at Mt. Abu, India, since 2001. This paper describes the main features of its various subsystems and its overall performance with regard to (a) tracking accuracy of its two-axes drive system, (b) spot size of the light collector, (c) back-end signal processing electronics and topological trigger generation scheme, (d) data acquisition and control system and (e) relative and absolute gain calibration methodology. Using a trigger field-of-view of 11x11 pixels (∼3.4 a tx3.4 a t), the telescope records a cosmic ray event rate of ∼2.5Hz at a typical zenith angle of 15 a t. Monte Carlo simulation results are also presented in the paper for comparing the expected performance of the telescope with actual observational results. The consistent detection of a steady signal from the Crab Nebula above ∼1.2TeV energy, at a sensitivity level of ∼5.0σ in ∼25h, along with excellent matching of its energy spectrum with that obtained by other groups, reassures that the performance of the TACTIC telescope is quite stable and reliable. Furthermore, encouraged by the detection of strong γ-ray signals from Mrk 501 (during 1997 and 2006 observations) and Mrk 421 (during 2001 and 2005-2006 observations), we believe that there is considerable scope for the TACTIC telescope to monitor similar TeV γ-ray emission activity from other active galactic nuclei on a long-term basis

Simulation of the Simbol-X telescope: imaging performance of a deformable x-ray telescope

Science.gov (United States)

Chauvin, Maxime; Roques, Jean-Pierre

2009-08-01

We have developed a simulation tool for a Wolter I telescope subject to deformations. The aim is to understand and predict the behavior of Simbol-X and other future missions (NuSTAR, Astro-H, IXO, ...). Our code, based on Monte-Carlo ray-tracing, computes the full photon trajectories up to the detector plane, along with the deformations. The degradation of the imaging system is corrected using metrology. This tool allows to perform many analyzes in order to optimize the configuration of any of these telescopes.

FACT. Bokeh alignment for Cherenkov telescopes

Energy Technology Data Exchange (ETDEWEB)

Mueller, Sebastian Achim [ETH Zurich (Switzerland); Buss, Jens [TU Dortmund (Germany)

2016-07-01

Imaging Atmospheric Cherenkov Telescopes (IACTs) need fast and large imaging optics to map the faint Cherenkov light emitted in cosmic ray air showers onto their image sensors. Segmented reflectors are inexpensive, lightweight and offer good image quality. However, alignment of the mirror facets remains a challenge. A good alignment is crucial in IACT observations to separate gamma rays from hadronic cosmic rays. We present a simple, yet extendable method, to align segmented reflectors using their Bokeh. Bokeh alignment does not need a star or good weather nights but can be done anytime, even during the day. Bokeh alignment optimizes the facet orientations by comparing the segmented reflector's Bokeh to a predefined template. The Bokeh is observed using the out of focus image of a nearby point like light source in a distance of about ten times the focal lengths. We introduce Bokeh alignment on segmented reflectors and present its use on the First Geiger-mode Avalanche Cherenkov Telescope (FACT) on Canary Island La Palma, as well as on the Cherenkov Telescope Array (CTA) Medium Size Telescope (MST) prototype in Berlin Adlershof.

Choosing and Using a Refracting Telescope

CERN Document Server

English, Neil

2011-01-01

The refracting telescope has a long and illustrious past. Here’s what the author says about early telescopes and today’s refractors: “Four centuries ago, a hitherto obscure Italian scientist turned a home-made spyglass towards the heavens. The lenses he used were awful by modern standards, inaccurately figured and filled with the scars of their perilous journey from the furnace to the finishing workshop. Yet, despite these imperfections, they allowed him to see what no one had ever seen before – a universe far more complex and dynamic than anyone had dared imagine. But they also proved endlessly useful in the humdrum of human affairs. For the first time ever, you could spy on your neighbor from a distance, or monitor the approach of a war-mongering army, thus deciding the fate of nations. “The refractor is without doubt the prince of telescopes. Compared with all other telescopic designs, the unobstructed view of the refractor enables it to capture the sharpest, highest contrast images and the wides...

Go-To Telescopes Under Suburban Skies

CERN Document Server

Monks, Neale

2010-01-01

For the last four centuries stargazers have turned their telescopes to the night skies to look at its wonders, but only in this age of computers has it become possible to let the telescope find for you the object you are looking for! So-called “go-to” telescopes are programmed with the locations of thousands of objects, including dazzling distant Suns, stunning neighboring galaxies, globular and open star clusters, the remnants of past supernovae, and many other breathtaking sights. This book does not tell you how to use your Go-to telescope. Your manual will help you do that. It tells you what to look for in the deep sky and why, and what equipment to best see it with. Organized broadly by what is best for viewing in the northern hemisphere in different seasons, Monks further divides the sights of each season into groupings such as “Showpiece Objects,” “Interesting Deep Sky Objects,” and “Obscure and Challenging Deep Sky Objects.” He also tells what objects are visible even in light-polluted ...

Telescoping cylindrical piezoelectric fiber composite actuator assemblies

Science.gov (United States)

Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

2010-01-01

A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

Neutrino telescopes sensitivity to dark matter

International Nuclear Information System (INIS)

Albuquerque, I.F.M.; Lamoureux, J.; Smoot, G.F.

2002-01-01

The nature of the dark matter of the Universe is yet unknown and most likely is connected with new physics. The search for its composition is underway through direct and indirect detection. Fundamental physical aspects such as energy threshold, geometry and location are taken into account to investigate proposed neutrino telescopes of km3 volume sensitivities to dark matter. These sensitivities are just sufficient to test a few weakly interacting massive particle scenarios. Telescopes of km3 volume, such as IceCube, can definitely discover or exclude superheavy (M>1010 GeV) strong interacting massive particles (simpzillas). Smaller neutrino telescopes such as ANTARES, AMANDA-II and NESTOR can probe a large region of simpzilla parameter space

THE SUBARCSECOND MID-INFRARED VIEW OF LOCAL ACTIVE GALACTIC NUCLEI. III. POLAR DUST EMISSION

International Nuclear Information System (INIS)

Asmus, D.; Hönig, S. F.; Gandhi, P.

2016-01-01

Recent mid-infrared (MIR) interferometric observations have shown that in a few active galactic nuclei (AGNs) the bulk of the infrared emission originates from the polar region above the putative torus, where only a little dust should be present. Here, we investigate whether such strong polar dust emission is common in AGNs. Out of 149 Seyferts in the MIR atlas of local AGNs, 21 show extended MIR emission on single-dish images. In 18 objects, the extended MIR emission aligns with the position angle (PA) of the system axis, established by [O iii], radio, polarization, and maser-based PA measurements. The relative amount of resolved MIR emission is at least 40% and scales with the [O iv] fluxes, implying a strong connection between the extended continuum and [O iv] emitters. These results together with the radio-quiet nature of the Seyferts support the scenario that the bulk of MIR emission is emitted by dust in the polar region and not by the torus, which would demand a new paradigm for the infrared emission structure in AGNs. The current low detection rate of polar dust in the AGNs of the MIR atlas is explained by the lack of sufficient high-quality MIR data and the requirements on the orientation, strength of narrow-line region, and distance of the AGNs. The James Webb Space Telescope will enable much deeper nuclear MIR studies with comparable angular resolution, allowing us to resolve the polar emission and surroundings in most of the nearby AGNs.

Source finding in linear polarization for LOFAR, and SKA predecessor surveys, using Faraday moments

Science.gov (United States)

Farnes, J. S.; Heald, G.; Junklewitz, H.; Mulcahy, D. D.; Haverkorn, M.; Van Eck, C. L.; Riseley, C. J.; Brentjens, M.; Horellou, C.; Vacca, V.; Jones, D. I.; Horneffer, A.; Paladino, R.

2018-03-01

The optimal source-finding strategy for linear polarization data is an unsolved problem, with many inhibitive factors imposed by the technically challenging nature of polarization observations. Such an algorithm is essential for Square Kilometre Array (SKA) pathfinder surveys, such as the Multifrequency Snapshot Sky Survey with the LOw Frequency ARray (LOFAR), as data volumes are significant enough to prohibit manual inspection. We present a new strategy of `Faraday Moments' for source-finding in linear polarization with LOFAR, using the moments of the frequency-dependent full-Stokes data (i.e. the mean, standard deviation, skewness, and excess kurtosis). Through simulations of the sky, we find that moments can identify polarized sources with a high completeness: 98.5 per cent at a signal to noise of 5. While the method has low reliability, rotation measure (RM) synthesis can be applied per candidate source to filter out instrumental and spurious detections. This combined strategy will result in a complete and reliable catalogue of polarized sources that includes the full sensitivity of the observational bandwidth. We find that the technique can reduce the number of pixels on which RM Synthesis needs to be performed by a factor of ≈1 × 105 for source distributions anticipated with modern radio telescopes. Through tests on LOFAR data, we find that the technique works effectively in the presence of diffuse emission. Extensions of this method are directly applicable to other upcoming radio surveys such as the POlarization Sky Survey of the Universe's Magnetism with the Australia Square Kilometre Array Pathfinder, and the SKA itself.

Liverpool Telescope 2: beginning the design phase

Science.gov (United States)

Copperwheat, Christopher M.; Steele, Iain A.; Barnsley, Robert M.; Bates, Stuart D.; Bode, Mike F.; Clay, Neil R.; Collins, Chris A.; Jermak, Helen E.; Knapen, Johan H.; Marchant, Jon M.; Mottram, Chris J.; Piascik, Andrzej S.; Smith, Robert J.

2016-07-01

The Liverpool Telescope is a fully robotic 2-metre telescope located at the Observatorio del Roque de los Muchachos on the Canary Island of La Palma. The telescope began routine science operations in 2004, and currently seven simultaneously mounted instruments support a broad science programme, with a focus on transient followup and other time domain topics well suited to the characteristics of robotic observing. Work has begun on a successor facility with the working title `Liverpool Telescope 2'. We are entering a new era of time domain astronomy with new discovery facilities across the electromagnetic spectrum, and the next generation of optical survey facilities such as LSST are set to revolutionise the field of transient science in particular. The fully robotic Liverpool Telescope 2 will have a 4-metre aperture and an improved response time, and will be designed to meet the challenges of this new era. Following a conceptual design phase, we are about to begin the detailed design which will lead towards the start of construction in 2018, for first light ˜2022. In this paper we provide an overview of the facility and an update on progress.

The Telescope: Outline of a Poetic History

Science.gov (United States)

Stocchi, M. P.

2011-06-01

Amongst the first editions of Galileo's books, only the Saggiatore has on its frontispiece the image of the telescope. Indeed, the telescope is not pictured on the very emphatic frontispieces of the other books in which Galileo was presenting and defending the results achieved by his celestial observations, such as the Sidereus Nuncius. Many contemporary scientists denied the reliability of the telescope, and some even refused to look into the eyepiece. In the 16th and 17th century, the lenses, mirrors, and optical devices of extraordinary complexity did not have the main task of leading to the objective truth but obtaining the deformation of the reality by means of amazing effects of illusion. The Baroque art and literature had the aim of surprising, and the artists gave an enthusiastic support to the telescope. The poems in praise of Galileo's telescopic findings were quite numerous, including Adone composed by Giovanni Battista Marino, one of the most renowned poets of the time. The Galilean discoveries were actually accepted by the poets as ideologically neutral contributions to the "wonder" in spite they were rejected or even condemned by the scientists, philosophers, and theologians.

Development and Performances of the Magic Telescope

Science.gov (United States)

Bastieri, D.; Bigongiari, C.; Dazzi, F.; Mariotti, M.; Moralejo, A.; Peruzzo, L.; Saggion, A.; Tonello, N.

2002-11-01

The MAGIC Collaboration is building an imaging Čerenkov telescope at La Palma site (2200 m a.s.l.), in the Canary Islands, to observe gamma rays in the hundred-GeV region. The MAGIC telescope, with its reflecting parabolic dish, 17 m in diameter, and a two-level pattern trigger designed to cope with severe trigger rates, is the Čerenkov telescope with the lowest envisaged energy threshold. Due to its lightweight alto-azimuthal mounting, MAGIC can be repositioned in less than 30 seconds, becoming the only detector, with an adequate effective area, capable to observe GRB phenomena above 30 GeV. MAGIC telescope is characterised by a 30 GeV energy threshold and a sensitivity of 6×l0-11 cm-2s-1 for a 5σ-detection in 50-hours of observation. In this report, some future scientific goals for MAGIC will be highlighted and the technical development for the main elements of the telescope will be detailed. Special emphasis will be given to the construction of the individual metallic mirrors which form the reflecting surface and the development of the fast pattern-recognition trigger.

A new concept of imaging system: telescope windows

Science.gov (United States)

Bourgenot, Cyril; Cowie, Euan; Young, Laura; Love, Gordon; Girkin, John; Courtial, Johannes

2018-02-01

A Telescope window is a novel concept of transformation-optics consisting of an array of micro-telescopes, in our configuration, of a Galilean type. When the array is considered as one multifaceted device, it acts as a traditional Galilean telescope with distinctive and attractive properties such as compactness and modularity. Each lenslet, can in principle, be independently designed for a specific optical function. In this paper, we report on the design, manufacture and prototyping, by diamond precision machining, of 2 concepts of telescope windows, and discuss both their performances and limitations with a view to use them as potential low vision aid devices to support patients with macular degeneration.

GISOT: a giant solar telescope

Science.gov (United States)

Hammerschlag, Robert H.; von der Lühe, Oskar F.; Bettonvil, Felix C.; Jägers, Aswin P.; Snik, Frans

2004-10-01

A concept is presented for an extremely large high-resolution solar telescope with an aperture of 11 m and diffraction limited for visual wavelengths. The structure of GISOT will be transparent to wind and placed on a transparent stiff tower. For efficient wind flushing, all optics, including the primary mirror, will be located above the elevation axis. The aperture will be of the order of 11 m, not rotatively symmetrical, but of an elongated shape with dimensions 11 x 4 m. It consists of a central on-axis 4 m mirror with on both sides 3 pieces of 2 m mirrors. The optical layout will be kept simple to guarantee quality and minimize stray light. A Coudé room for instruments is planned below the telescope. The telescope will not be housed in a dome-like construction, which interferes with the open principle. Instead the telescope will be protected by a foldable tent construction with a diameter of the order of 30 m, which doesn"t form any obstruction during observations, but can withstand the severe weather circumstances on mountain sites. Because of the nature of the solar scene, extremely high resolution in only one dimension is sufficient to solve many exciting problems in solar physics and in this respect the concept of GISOT is very promising.

Undergraduate Education with the WIYN 0.9-m Telescope

Science.gov (United States)

Pilachowski, Catherine A.

2017-01-01

Several models have been explored at Indiana University Bloomington for undergraduate student engagement in astronomy using the WIYN 0.9-m telescope at Kitt Peak. These models include individual student research projects using the telescope, student observations as part of an observational techniques course for majors, and enrichment activities for non-science majors in general education courses. Where possible, we arrange for students to travel to the telescope. More often, we are able to use simple online tools such as Skype and VNC viewers to give students an authentic observing experience. Experiences with the telescope motivate students to learn basic content in astronomy, including the celestial sphere, the electromagnetic spectrum, telescopes and detectors, the variety of astronomical objects, date reduction processes, image analysis, and color image creation and appreciation. The WIYN 0.9-m telescope is an essential tool for our program at all levels of undergraduate education

Aplanatic telescopes based on Schwarzschild optical configuration: from grazing incidence Wolter-like x-ray optics to Cherenkov two-mirror normal incidence telescopes

Science.gov (United States)

Sironi, Giorgia

2017-09-01

At the beginning of XX century Karl Schwarzschild defined a method to design large-field aplanatic telescopes based on the use of two aspheric mirrors. The approach was then refined by Couder (1926) who, in order to correct for the astigmatic aberration, introduced a curvature of the focal plane. By the way, the realization of normal-incidence telescopes implementing the Schwarzschild aplanatic configuration has been historically limited by the lack of technological solutions to manufacture and test aspheric mirrors. On the other hand, the Schwarzschild solution was recovered for the realization of coma-free X-ray grazing incidence optics. Wolter-like grazing incidence systems are indeed free of spherical aberration, but still suffer from coma and higher order aberrations degrading the imaging capability for off-axis sources. The application of the Schwarzschild's solution to X-ray optics allowed Wolter to define an optical system that exactly obeys the Abbe sine condition, eliminating coma completely. Therefore these systems are named Wolter-Schwarzschild telescopes and have been used to implement wide-field X-ray telescopes like the ROSAT WFC and the SOHO X-ray telescope. Starting from this approach, a new class of X-ray optical system was proposed by Burrows, Burg and Giacconi assuming polynomials numerically optimized to get a flat field of view response and applied by Conconi to the wide field x-ray telescope (WFXT) design. The Schwarzschild-Couder solution has been recently re-discovered for the application to normal-incidence Cherenkov telescopes, thanks to the suggestion by Vassiliev and collaborators. The Italian Institute for Astrophysics (INAF) realized the first Cherenkov telescope based on the polynomial variation of the Schwarzschild configuration (the so-called ASTRI telescope). Its optical qualification was successfully completed in 2016, demonstrating the suitability of the Schwarzschild-like configuration for the Cherenkov astronomy requirements

Observations of Near-Earth Asteroids in Polarized Light

Science.gov (United States)

Afanasiev, V. L.; Ipatov, A. V.

2018-04-01

We report the results of position, photometric, and polarimetric observations of two near-Earth asteroids made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. 1.2-hour measurements of the photometric variations of the asteroid 2009 DL46 made onMarch 8, 2016 (approximately 20m at a distance of about 0.23 AU from the Earth) showed a 0.m2-amplitude flash with a duration of about 20 minutes. During this time the polarization degree increased from the average level of 2-3% to 14%. The angle of the polarization plane and the phase angle were equal to 113° ± 1° and 43°, respectively. Our result indicates that the surface of the rotating asteroid (the rotation period of about 2.5 hours) must be non-uniformly rough. Observations of another asteroid—1994 UG—whose brightness was of about 17m and which was located at a geocentric distance of 0.077 AU, were carried out during the night of March 6/7, 2016 in two modes: photometric and spectropolarimetric. According to the results of photometric observations in Johnson's B-, V-, and R-band filters, over one hour the brightness of the asteroid remained unchanged within the measurement errors (about 0.m02). Spectropolarimetric observations in the 420-800 nm wavelength interval showed the polarization degree to decrease from 8% in the blue part of the spectrum to 2% in the red part with the phase angle equal to 44°, which is typical for S-type near-Earth asteroids.

Radio telescope control

CERN Document Server

Schraml, J

1972-01-01

An on-line computer control process developed for the 100-m radio telescope of the Max-Planck-Institut fur Radioastronomie in Bonn is described. The instrument is the largest fully steerable antenna in the world. Its operation started on May 31st 1972. It is controlled by a Ferranti Argus 500 on-line computer. The first part of the paper deals with the process itself, the radio telescope and its operation, and the demands resulting for the control program. The second part briefly describes the computer and its hardware. The final part introduces the architecture of the executive program in general, which has been tailored to meet the demands of the process and the hardware. The communication between the observer and the system, the format of data on magnetic tape and an on-line reduction of position measurements are considered. (0 refs).

The JCMT Telescope Management System

Science.gov (United States)

Tilanus, Remo P. J.; Jenness, Tim; Economou, Frossie; Cockayne, Steve

Established telescopes often face a challenge when trying to incorporate new software standards and utilities into their existing real-time control system. At the JCMT we have successfully added important new features such as a Relational Database (the Telescope Management System---TMS), an online data Archive, and WWW based utilities to an, in part, 10-year old system. The new functionality was added with remarkably few alterations to the existing system. We are still actively expanding and exploring these new capabilities.

Evidence for Dark Energy from the Cosmic Microwave Background Alone Using the Atacama Cosmology Telescope Lensing Measurements

Science.gov (United States)

Sherwin, Blake D.; Dunkley, Joanna; Das, Sudeep; Appel, John W.; Bond, J. Richard; Carvalho, C. Sofia; Devlin, Mark J.; Duenner, Rolando; Essinger-Hileman, Thomas; Fowler, Joesph J.;

Evidence for dark energy from the cosmic microwave background alone using the Atacama Cosmology Telescope lensing measurements.

Science.gov (United States)

Sherwin, Blake D; Dunkley, Joanna; Das, Sudeep; Appel, John W; Bond, J Richard; Carvalho, C Sofia; Devlin, Mark J; Dünner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W; Hajian, Amir; Halpern, Mark; Hasselfield, Matthew; Hincks, Adam D; Hlozek, Renée; Hughes, John P; Irwin, Kent D; Klein, Jeff; Kosowsky, Arthur; Marriage, Tobias A; Marsden, Danica; Moodley, Kavilan; Menanteau, Felipe; Niemack, Michael D; Nolta, Michael R; Page, Lyman A; Parker, Lucas; Reese, Erik D; Schmitt, Benjamin L; Sehgal, Neelima; Sievers, Jon; Spergel, David N; Staggs, Suzanne T; Swetz, Daniel S; Switzer, Eric R; Thornton, Robert; Visnjic, Katerina; Wollack, Ed

2011-07-08

For the first time, measurements of the cosmic microwave background radiation (CMB) alone favor cosmologies with w = -1 dark energy over models without dark energy at a 3.2-sigma level. We demonstrate this by combining the CMB lensing deflection power spectrum from the Atacama Cosmology Telescope with temperature and polarization power spectra from the Wilkinson Microwave Anisotropy Probe. The lensing data break the geometric degeneracy of different cosmological models with similar CMB temperature power spectra. Our CMB-only measurement of the dark energy density Ω(Λ) confirms other measurements from supernovae, galaxy clusters, and baryon acoustic oscillations, and demonstrates the power of CMB lensing as a new cosmological tool.

Solar Lyman-Alpha Polarization Observation of the Chromosphere and Transition Region by the Sounding Rocket Experiment CLASP

Science.gov (United States)

Narukage, Noriyuki; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Kubo, Masahito; Katsukawa, Yukio; Ishikawa, Shinnosuke; Hara, Hiroshi; Suematsu, Yoshinori; Giono, Gabriel;

Development of Slewing Mirror Telescope Optical System for the UFFO-pathfinder

DEFF Research Database (Denmark)

Jeong, S.; Nam, J.W.; Ahn, K.-B.

2013-01-01

The Slewing Mirror Telescope (SMT) is the UV/optical telescope of UFFO-pathfinder. The SMT optical system is a Ritchey-Chrétien (RC) telescope of 100 mm diameter pointed by means of a gimbal-mounted flat mirror in front of the telescope. The RC telescope has a 17 × 17arcmin2 in Field of View and ...

Academic Training: Deep Space Telescopes

CERN Multimedia

Françoise Benz

2006-01-01

2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 20, 21, 22, 23, 24 February from 11:00 to 12:00 - Council Chamber on 20, 21, 23, 24 February, TH Auditorium, bldg 4 - 3-006, on 22 February Deep Space Telescopes G. BIGNAMI / CNRS, Toulouse, F & Univ. di Pavia, I The short series of seminars will address results and aims of current and future space astrophysics as the cultural framework for the development of deep space telescopes. It will then present such new tools, as they are currently available to, or imagined by, the scientific community, in the context of the science plans of ESA and of all major world space agencies. Ground-based astronomy, in the 400 years since Galileo's telescope, has given us a profound phenomenological comprehension of our Universe, but has traditionally been limited to the narrow band(s) to which our terrestrial atmosphere is transparent. Celestial objects, however, do not care about our limitations, and distribute most of the information about their physics thro...

Observations of Anomalous Refraction with Co-housed Telescopes

Science.gov (United States)

Taylor, Malinda S.; McGraw, J. T.; Zimmer, P. C.

2013-01-01

Anomalous refraction is described as a low frequency, large angular scale motion of the entire image plane with respect to the celestial coordinate system as observed and defined by previous astrometric catalogs. These motions of typically several tenths of an arcsecond with timescales on the order of ten minutes are ubiquitous to drift-scan ground-based astrometric measurements regardless of location or telescopes used and have been attributed to meter scale slowly evolving coherent dynamical structures in the boundary-layer below 60 meters. The localized nature of the effect and general inconsistency of the motions seen by even closely spaced telescopes in individual domes has led to the hypothesis that the dome or other type of telescope housing may be responsible. This hypothesis is tested by observing anomalous refraction using two telescopes housed in a single roll-off roof observatory building with the expected outcome that the two telescopes will see correlated anomalous refraction induced motions.

Ideas for future large single dish radio telescopes

Science.gov (United States)

Kärcher, Hans J.; Baars, Jacob W. M.

2014-07-01

The existing large single dish radio telescopes of the 100m class (Effelsberg, Green Bank) were built in the 1970s and 1990s. With some active optics they work now down to 3 millimeter wavelength where the atmospheric quality of the site is also a limiting factor. Other smaller single dish telescopes (50m LMT Mexico, 30m IRAM Spain) are located higher and reach sub-millimeter quality, and the much smaller 12m antennas of the ALMA array reach at a very high site the Terahertz region. They use advanced technologies as carbon fiber structures and flexible body control. We review natural limits to telescope design and use the examples of a number of telescopes for an overview of the available state-of-the-art in design, engineering and technologies. Without considering the scientific justification we then offer suggestions to realize ultimate performance of huge single dish telescopes (up to 160m). We provide an outlook on design options, technological frontiers and cost estimates.

Revisiting the Effectiveness of Large Optical Telescopes

Directory of Open Access Journals (Sweden)

V. V. Sychev

2015-01-01

Full Text Available To create large-size optical telescopes, various design concepts have been used. Each concept inevitably faced the challenge to optimize technical characteristics and parameters of the telescope. There was always a question: what concept to choose, how to estimate efficiency of such telescopes and by what criteria and how to estimate expediency of this or that project of the large-size telescope. It is, obviously, insufficient to make a resolution-based estimation. An estimate by the angular field size is inappropriate too. Well, it may be also an estimate by the stellar magnitude. All these criteria are related to each other. Improvement of one of these parameters inevitably leads to deterioration of the others. Obviously, the certain generalized criterion considering all parameters and features of the design concept of the large-size telescope is necessary here. As such can serve the criterion of informational content of the telescope.The article offers a complex criterion allowing not only to estimate efficiency of large-size optical telescopes, but also to compare their conceptual and technological level among themselves in terms of obtaining information.The article suggests a new term, i.e. the informational content invariant to characterize informative capacities of the chosen concept and of the realizing technology. It will allow us to avoid unjustified complications of technical solutions, wrong accents in designing and excess material inputs when developing the project.The informational content criterion-based analysis of the existing projects of large-size telescopes has been convincingly shown that, conceptually, there are three best telescopes, namely: GSMT, CELT, and ACT-25. And, in terms of informational content, the АCТ-25 is 10 times more than GSMT and CELT, and the existing Keck-telescope exceeds by 30 times. Hence, it is hard to escape a conclusion that it is more favourable to implement one ACT-25, than to do 10 GSMT or CELT

Simulation of the Simbol-X Telescope

International Nuclear Information System (INIS)

Chauvin, M.; Roques, J. P.

2009-01-01

We have developed a simulation tool for a Wolter I telescope operating in formation flight. The aim is to understand and predict the behavior of the Simbol-X instrument. As the geometry is variable, formation flight introduces new challenges and complex implications. Our code, based on Monte Carlo ray tracing, computes the full photon trajectories up to the detector plane, along with the relative drifts of the two spacecrafts. It takes into account angle and energy dependent interactions of the photons with the mirrors and applies to any grazing incidence telescope. The resulting images of simulated sources from 0.1 keV to 100 keV allow us to optimize the configuration of the instrument and to assess the performance of the Simbol-X telescope.

Simulation of the Simbol-X Telescope

Science.gov (United States)

Chauvin, M.; Roques, J. P.

2009-05-01

We have developed a simulation tool for a Wolter I telescope operating in formation flight. The aim is to understand and predict the behavior of the Simbol-X instrument. As the geometry is variable, formation flight introduces new challenges and complex implications. Our code, based on Monte Carlo ray tracing, computes the full photon trajectories up to the detector plane, along with the relative drifts of the two spacecrafts. It takes into account angle and energy dependent interactions of the photons with the mirrors and applies to any grazing incidence telescope. The resulting images of simulated sources from 0.1 keV to 100 keV allow us to optimize the configuration of the instrument and to assess the performance of the Simbol-X telescope.

The VTIE telescope resource management system

Science.gov (United States)

Busschots, B.; Keating, J. G.

2005-06-01

The VTIE Telescope Resource Management System (TRMS) provides a frame work for managing a distributed group of internet telescopes as a single "Virtual Observatory". The TRMS provides hooks which allow for it to be connected to any Java Based web portal and for a Java based scheduler to be added to it. The TRMS represents each telescope and observatory in the system with a software agent and then allows the scheduler and web portal to communicate with these distributed resources in a simple transparent way, hence allowing the scheduler and portal designers to concentrate only on what they wish to do with these resources rather than how to communicate with them. This paper outlines the structure and implementation of this frame work.

A STUDY OF BROADBAND FARADAY ROTATION AND POLARIZATION BEHAVIOR OVER 1.3–10 GHz IN 36 DISCRETE RADIO SOURCES

International Nuclear Information System (INIS)

Anderson, C. S.; Gaensler, B. M.; Feain, I. J.

2016-01-01

We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely sampled frequency band. Our sample was selected on the basis of polarization behavior apparent in narrowband archival data at 1.4 GHz: half the sample shows complicated frequency-dependent polarization behavior (i.e., Faraday complexity) at these frequencies, while half shows comparatively simple behavior (i.e., they appear Faraday simple ). We re-observed the sample using the Australia Telescope Compact Array in full polarization, with 6 GHz of densely sampled frequency coverage spanning 1.3–10 GHz. We have devised a general polarization modeling technique that allows us to identify multiple polarized emission components in a source, and to characterize their properties. We detect Faraday complex behavior in almost every source in our sample. Several sources exhibit particularly remarkable polarization behavior. By comparing our new and archival data, we have identified temporal variability in the broadband integrated polarization spectra of some sources. In a number of cases, the characteristics of the polarized emission components, including the range of Faraday depths over which they emit, their temporal variability, spectral index, and the linear extent of the source, allow us to argue that the spectropolarimetric data encode information about the magneto-ionic environment of active galactic nuclei themselves. Furthermore, the data place direct constraints on the geometry and magneto-ionic structure of this material. We discuss the consequences of restricted frequency bands on the detection and interpretation of polarization structures, and the implications for upcoming spectropolarimetric surveys.

Direct illumination LED calibration for telescope photometry

International Nuclear Information System (INIS)

Barrelet, E.; Juramy, C.

2008-01-01

A calibration method for telescope photometry, based on the direct illumination of a telescope with a calibrated light source regrouping multiple LEDs, is proposed. Its purpose is to calibrate the instrument response. The main emphasis of the proposed method is the traceability of the calibration process and a continuous monitoring of the instrument in order to maintain a 0.2% accuracy over a period of years. Its specificity is to map finely the response of the telescope and its camera as a function of all light ray parameters. This feature is essential to implement a computer model of the instrument representing the variation of the overall light collection efficiency of each pixel for various filter configurations. We report on hardware developments done for SNDICE, the first application of this direct illumination calibration system which will be installed in Canada France Hawaii telescope (CFHT) for its leading supernova experiment (SNLS)

Far Sidelobes Measurement of the Atacama Cosmology Telescope

Science.gov (United States)

Duenner, Rolando; Gallardo, Patricio; Wollack, Ed; Henriquez, Fernando; Jerez-Hanckes, Carlos

2012-01-01

The Atacama Cosmology Telescope (ACT) is a 6m telescope designed to map the Cosmic Microwave Background (CMB) simultaneously at 145GHz, 220 GHz and 280 GHz. Its off-axis Gregorian design is intended to minimize and control the off-axis sidelobe response, which is critical for scientific purposes. The expected sidelobe level for this kind of design is less than -50 dB and can be challenging to measure. Here we present a measurement of the 145 GHz far sidelobes of ACT done on the near-field of the telescope. We used a 1 mW microwave source placed 13 meters away from the telescope and a chopper wheel to produce a varying signal that could be detected by the camera for different orientations of the telescope. The source feed was designed to produce a wide beam profile. Given that the coupling is expected to be dominated by diffraction over the telescope shielding structure, when combined with a measurements of the main beam far field response, these measurement can be used to validate elements of optical design and constrain the level of spurious coupling at large angles. Our results show that the diffractive coupling beyond the ground screen is consistently below -75 dB, satisfying the design expectations.

[Galileo and his telescope].

Science.gov (United States)

Strebel, Christoph

2006-01-01

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

Solar orbiter/PHI full disk telescope entrance window mechanical mount

Science.gov (United States)

Barandiaran, J.; Zuluaga, P.; Fernandez, A. B.; Vera, I.; Garranzo, D.; Nuñez, A.; Bastide, L.; Royo, M. T.; Alvarez, A.

2017-11-01

PHI is a diffraction limited, wavelength tunable, quasi-monochromatic, and polarization sensitive imager. These capabilities are needed to infer the magnetic field and line-of-sight (LOS) velocity of the region targeted by the spacecraft (spacecraft (S/C)). PHI will consist of two telescopes: The High Resolution Telescope (HRT)[1] and the Full Disk Telescope (FDT). The HRT and the FDT will view the Sun through entrance windows located in the S/C heat shield. These windows act as heat rejecting filters with a transmission band of about 30 nm width centered on the science wavelength, such that the total transmittance (integral over the filter curve weighted with solar spectrum, including white leakage plus transmission profile of the pass band) does not exceed 4% of the total energy falling onto the window [2][3]. The HREW filter has been designed by SELEX in the framework of an ESA led technology development activity under original ESTEC contract No. 20018/06/NL/CP[4], and extensions thereof. For FDT HREW SLEX will provide the windows and it coatings. The HREW consists of two parallel-plane substrate plates (window 1 & window 2)[5] made of SUPRASIL 300 with a central thickness of 9 mm and a wedge of 30 arcsec each. These two substrates are each coated on both sides with four different coatings. These coatings and the choice of SUPRASIL help to minimize the optical absorptivity in the substrate and to radiatively decouple the HREW, which is expected to run at high temperatures during perihelion passages, from the PHI instrument cavity. The temperature distribution of the HREW is driven by two main factors: the mechanical mounting of the substrates to the feedthrough, and the radiative environment within the heat-shield/feedthrough assembly. The mechanical mount must ensure the correct integration of both suprasil substrates in its correct position and minimize the loads in windows due to thermal induced deformations and launching vibration environment. All the

The Associate Principal Astronomer for AI Management of Automatic Telescopes

Science.gov (United States)

Henry, Gregory W.

1998-01-01

This research program in scheduling and management of automatic telescopes had the following objectives: 1. To field test the 1993 Automatic Telescope Instruction Set (ATIS93) programming language, which was specifically developed to allow real-time control of an automatic telescope via an artificial intelligence scheduler running on a remote computer. 2. To develop and test the procedures for two-way communication between a telescope controller and remote scheduler via the Internet. 3. To test various concepts in Al scheduling being developed at NASA Ames Research Center on an automatic telescope operated by Tennessee State University at the Fairborn Observatory site in southern Arizona. and 4. To develop a prototype software package, dubbed the Associate Principal Astronomer, for the efficient scheduling and management of automatic telescopes.

An off-the-shelf guider for the Palomar 200-inch telescope: interfacing amateur astronomy software with professional telescopes for an easy life

Science.gov (United States)

Clarke, Fraser; Lynn, James; Thatte, Niranjan; Tecza, Matthias

2014-08-01

We have developed a simple but effective guider for use with the Oxford-SWIFT integral field spectrograph on the Palomar 200-inch telescope. The guider uses mainly off-the-shelf components, including commercial amateur astronomy software to interface with the CCD camera, calculating guiding corrections, and send guide commands to the telescope. The only custom piece of software is an driver to provide an interface between the Palomar telescope control system and the industry standard 'ASCOM' system. Using existing commercial software provided a very cheap guider (guiding, and could easily be adapted to any other professional telescope

A RESOLVED NEAR-INFRARED IMAGE OF THE INNER CAVITY IN THE GM Aur TRANSITIONAL DISK

Energy Technology Data Exchange (ETDEWEB)

Oh, Daehyeon; Yang, Yi [Department of Astronomical Science, SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Hashimoto, Jun; Kusakabe, Nobuhiko [Astrobiology Center of NINS 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Carson, Joseph C. [Department of Physics and Astronomy, College of Charleston 66 George Street, Charleston, SC 29424 (United States); Janson, Markus [Department of Astronomy, Stockholm University, AlbaNova University Center SE-106 91 Stockholm (Sweden); Kwon, Jungmi; Nakagawa, Takao [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan); Mayama, Satoshi [The Center for the Promotion of Integrated Sciences, SOKENDAI (The Graduate University for Advanced Studies), Shonan International Village, Hayama-cho, Miura-gun, Kanagawa 240-0193 (Japan); Uyama, Taichi [Department of Astronomy, The University of Tokyo 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Kudo, Tomoyuki; Currie, Thayne [Subaru Telescope, National Astronomical Observatory of Japan 650 North A’ohoku Place, Hilo, HI 96720 (United States); Abe, Lyu [Laboratoire Lagrange (UMR 7293), Universite de Nice-Sophia Antipolis, CNRS, Observatoire de la Coted’azur 28 avenue Valrose, F-06108 Nice Cedex 2 (France); Akiyama, Eiji [National Astronomical Observatory of Japan 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Brandner, Wolfgang [Max Planck Institute for Astronomy, Köonigstuhl 17, D-69117 Heidelberg (Germany); Brandt, Timothy D.; Feldt, Markus [Astrophysics Department, Institute for Advanced Study Princeton, NJ (United States); Goto, Miwa [Universitats-Sternwarte Munchen, Ludwig-Maximilians-Universitat, Scheinerstr. 1, D-81679 Munchen (Germany); Grady, Carol A. [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center Greenbelt, MD 20771 (United States); and others

2016-11-01

We present high-contrast H -band polarized intensity (PI) images of the transitional disk around the young solar-like star GM Aur. The near-infrared direct imaging of the disk was derived by polarimetric differential imaging using the Subaru 8.2 m Telescope and HiCIAO. An angular resolution and an inner working angle of 0.″07 and r ∼ 0.″05, respectively, were obtained. We clearly resolved a large inner cavity, with a measured radius of 18 ± 2 au, which is smaller than that of a submillimeter interferometric image (28 au). This discrepancy in the cavity radii at near-infrared and submillimeter wavelengths may be caused by a 3–4 M {sub Jup} planet about 20 au away from the star, near the edge of the cavity. The presence of a near-infrared inner cavity is a strong constraint on hypotheses for inner cavity formation in a transitional disk. A dust filtration mechanism has been proposed to explain the large cavity in the submillimeter image, but our results suggest that this mechanism must be combined with an additional process. We found that the PI slope of the outer disk is significantly different from the intensity slope obtained from HST /NICMOS, and this difference may indicate the grain growth process in the disk.

Telescope Construction: A Hands-On Approach to Astronomy Education

Science.gov (United States)

Sarrazine, Angela R.; Albin, E.

2009-01-01

We report on a popular semester-long telescope making course offered at Fernbank Science Center in Atlanta, GA. The program is tailored for junior / senior level high school students and incorporates the current educational performance standards for the state of Georgia. This course steps out of the traditional classroom environment and allows students to explore optics and astronomical concepts by constructing their own telescopes. Student telescopes follow the classic six-inch f/8 Newtonian reflector design, which has proven to be a good compromise between portability and aperture. Participants meet for a few hours, twice weekly, to build their telescopes. Over the course of the semester, raw one-inch thick Pyrex mirror blanks are ground, polished, and figured by hand into precision telescope objectives. Along the way, students are introduced to the Ronchi and Foucault methods for testing optics and once figured, completed mirrors are then chemically silvered. A plywood Dobsonian-style base is built and eventually mated with an optical tube made from a standard eight-inch concrete form tube or sonotube. An evening of star testing the optics and observation is planned at the end of the semester to insure the proper operation of each telescope. In summary, we believe that a hands-on approach to the understanding and use of optical telescopes is a great way not only to instill enthusiasm among students for the night sky, but may perhaps inspire the next generation of professional telescope makers.

Hubble Space Telescope, Faint Object Camera

Science.gov (United States)

1981-01-01

This drawing illustrates Hubble Space Telescope's (HST's), Faint Object Camera (FOC). The FOC reflects light down one of two optical pathways. The light enters a detector after passing through filters or through devices that can block out light from bright objects. Light from bright objects is blocked out to enable the FOC to see background images. The detector intensifies the image, then records it much like a television camera. For faint objects, images can be built up over long exposure times. The total image is translated into digital data, transmitted to Earth, and then reconstructed. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

The big data telescope

International Nuclear Information System (INIS)

Finkel, Elizabeth

2017-01-01

On a flat, red mulga plain in the outback of Western Australia, preparations are under way to build the most audacious telescope astronomers have ever dreamed of - the Square Kilometre Array (SKA). Next-generation telescopes usually aim to double the performance of their predecessors. The Australian arm of SKA will deliver a 168-fold leap on the best technology available today, to show us the universe as never before. It will tune into signals emitted just a million years after the Big Bang, when the universe was a sea of hydrogen gas, slowly percolating with the first galaxies. Their starlight illuminated the fledgling universe in what is referred to as the “cosmic dawn”.

Development of a Telescope for Medium-Energy Gamma-ray Astronomy

Science.gov (United States)

Sunter, Stan

2012-01-01

Since the launch of AGILE and FERMI, the scientific progress in high-energy (Eg greater than approximately 200 MeV) gamma-ray science has been, and will continue to be dramatic. Both of these telescopes cover a broad energy range from approximately 20 MeV to greater than 10 GeV. However, neither instrument is optimized for observations below approximately 200 MeV where many astrophysical objects exhibit unique, transitory behavior, such as spectral breaks, bursts, and flares. Hence, while significant progress from current observations is expected, there will nonetheless remain a significant sensitivity gap in the medium-energy (approximately 0.1-200 MeV) regime; the lower end of this range remains largely unexplored whereas the upper end will allow comparison with FERMI data. Tapping into this unexplored regime requires significant improvements in sensitivity. A major emphasis of modern detector development, with the goal of providing significant improvements in sensitivity in the medium-energy regime, focuses on high-resolution electron tracking. The Three-Dimensional Track Imager (3-DTI) technology being developed at GSFC provides high resolution tracking of the electron-positron pair from gamma-ray interactions from 5 to 200 MeV. The 3-DTI consists of a time projection chamber (TPC) and 2-D cross-strip microwell detector (MWD). The low-density and homogeneous design of the 3-DTI, offers unprecedented sensitivity by providing angular resolution near the kinematic limit. Electron tracking also enables measurement of gamma-ray polarization, a new tool to study astrophysical phenomenon. We describe the design, fabrication, and performance of a 30x30x30 cm3 3-DTI detector prototype of a medium-energy gamma-ray telescope.

Polarization of lanthanum nucleus by dynamic polarization method

International Nuclear Information System (INIS)

Adachi, Toshikazu; Ishimoto, Shigeru; Masuda, Yasuhiro; Morimoto, Kimio

1989-01-01

Preliminary studies have been carried out concerning the application of a dynamic polarization method to polarizing lanthanum fluoride single crystal to be employed as target in experiments with time reversal invariance. The present report briefly outlines the dynamic polarization method and describes some preliminary studies carried out so far. Dynamic polarization is of particular importance because no techniques are currently available that can produce highly polarized static nucleus. Spin interaction between electrons and protons (nuclei) plays a major role in the dynamic polarization method. In a thermal equilibrium state, electrons are polarized almost completely while most protons are not polarized. Positively polarized proton spin is produced by applying microwave to this system. The most hopeful candidate target material is single crystal of LaF 3 containing neodymium because the crystal is chemically stable and easy to handle. The spin direction is of great importance in experiments with time reversal invariance. The spin of neutrons in the target can be cancelled by adjusting the external magnetic field applied to a frozen polarized target. In a frozen spin state, the polarity decreases slowly with a relaxation time that depends on the external magnetic field and temperature. (N.K.)

Proxy magnetometry with the Dutch Open Telescope

NARCIS (Netherlands)

Rutten, R.J.; Hammerschlag, R.H.; Sütterlin, P.; Bettonvil, F.C.M.

1999-01-01

Superb movies from the Dutch Open Telescope (DOT) on La Palma have proven the validity of the open concept of this innovative telescope for high-resolution imaging of the solar atmosphere. A five- camera speckle-burst registration system is being installed that should permit consistent and

Polarized neutrons

International Nuclear Information System (INIS)

Williams, W.G.

1988-01-01

The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

Pulsed Gamma-Rays From PSR J2021 3651 with the Fermi Large Area Telescope

Energy Technology Data Exchange (ETDEWEB)

Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, Marco; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, William B.; /UC, Santa Cruz; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Battelino, Milan; /Royal Inst. Tech., Stockholm; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, Ronaldo; /INFN, Pisa; Berenji, Bijan; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, Elliott D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bogaert, G.; /Ecole Polytechnique; Borgland, Anders W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, Thompson H.; /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Columbia U. /IASF, Milan /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /IASF, Milan /IASF, Milan /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /LPCE, Orleans /Montpellier U. /Sonoma State U. /Royal Inst. Tech., Stockholm /Stockholm U. /ASI, Rome /NRAO, Charlottesville /Naval Research Lab, Wash., D.C. /INFN, Trieste /Pavia U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /UC, Santa Cruz /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Manchester U. /Montpellier U. /Bari U. /INFN, Bari; /more authors..

2011-11-30

We report the detection of pulsed gamma-rays from the young, spin-powered radio pulsar PSR J2021+3651 using data acquired with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The light curve consists of two narrow peaks of similar amplitude separated by 0.468 {+-} 0.002 in phase. The first peak lags the maximum of the 2 GHz radio pulse by 0.162 {+-} 0.004 {+-} 0.01 in phase. The integral gamma-ray photon flux above 100 MeV is (56 {+-} 3 {+-} 11) x 10{sup -8} cm{sup -2} s{sup -1}. The photon spectrum is well-described by an exponentially cut-off power law of the form dF/dE = kE{sup -{Gamma}}e{sup (-E/E{sub c})} where the energy E is expressed in GeV. The photon index is {Gamma} = 1.5 {+-} 0.1 {+-} 0.1 and the exponential cut-off is E{sub c} = 2.4 {+-} 0.3 {+-} 0.5 GeV. The first uncertainty is statistical and the second is systematic. The integral photon flux of the bridge is approximately 10% of the pulsed emission, and the upper limit on off-pulse gamma-ray emission from a putative pulsar wind nebula is < 10% of the pulsed emission at the 95% confidence level. Radio polarization measurements yield a rotation measure of RM = 524 {+-} 4 rad m{sup -2} but a poorly constrained magnetic geometry. Re-analysis of Chandra data enhanced the significance of the weak X-ray pulsations, and the first peak is roughly phase-aligned with the first gamma-ray peak. We discuss the emission region and beaming geometry based on the shape and spectrum of the gamma-ray light curve combined with radio and X-ray measurements, and the implications for the pulsar distance. Gamma-ray emission from the polar cap region seems unlikely for this pulsar.

Possible GRB Observation with the MAGIC Telescope

Science.gov (United States)

Bastieri, D.; Bigongiari, C.; Mariotti, M.; Peruzzo, L.; Saggion, A.

2001-08-01

The MAGIC Telescope, with its reflecting parabolic dish of 17 m of diameter and its careful design of a robust, lightweight, alto-azimuthal mount, is an ideal detector for GRB phenomena. The telescope is an air Cherenkov telescope that, even in the first phase, equipped with standard PMTs, can reach an energy threshold below 30 GeV. The threshold is going to drop well below 10 GeV in the envisaged second phase, when chamber PMTs will be substituted by high quantum efficiency APDs. The telescope can promptly respond to GRB alerts coming, for instance, from GCN, and can reposition itself in less than 30 seconds, 20 seconds being the time to turn half a round for the azimuth bearing. In this report, the effective area of the detector as a function of energy and zenith angle is taken into account, in order to evaluate the expected yearly occurrence and the response to different kinds of GRBs.

Space telescopes capturing the rays of the electromagnetic spectrum

CERN Document Server

English, Neil

2017-01-01

Space telescopes are among humankind’s greatest scientific achievements of the last fifty years. This book describes the instruments themselves and what they were designed to discover about the Solar System and distant stars. Exactly how these telescopes were built and launched and the data they provided is explored. Only certain kinds of radiation can penetrate our planet's atmosphere, which limits what we can observe. But with space telescopes all this changed. We now have the means to "see" beyond Earth using ultraviolet, microwave, and infrared rays, X-rays and gamma rays. In this book we meet the pioneers and the telescopes that were built around their ideas. This book looks at space telescopes not simply chronologically but also in order of the electromagnetic spectrum, making it possible to understand better why they were made.

A semiconductor counter telescope for neutron reaction studies

Energy Technology Data Exchange (ETDEWEB)

Lalovic, B I; Ajdacic, V S [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1963-12-15

A counter telescope consisting of two or three semiconductor counters for {delta}E/{delta}x vs. E analysis was made for studying nuclear reactions induced by 14.4 MeV neutrons. Various factors important for the telescope performance are discussed in details and some solutions for getting an optimum resolution and a low background are given. Protons, deuterons and alpha particles resulting from scattering and reactions of 14.4 MeV neutrons on deuterium, tritium, praseodymium and niobium were detected, and pulses from the counters recorded on a two-dimensional analyzer. These experiments have shown that the telescope compares favorably with other types of telescopes with regards to the upper limit of neutron flux which can be used, (DELTADELTA)x and E resolution, versatility and compactness (author)

LCOGT: A World-Wide Network of Robotic Telescopes

Science.gov (United States)

Brown, T.

2013-05-01

Las Cumbres Observatory Global Telescope (LCOGT) is an organization dedicated to time-domain astronomy. To carry out the necessary observations in fields such as supernovae, extrasolar planets, small solar-system bodies, and pulsating stars, we have developed and are now deploying a set of robotic optical telescopes at sites around the globe. In this talk I will concentrate on the core of this network, consisting of up to 15 identical 1m telescopes deployed across multiple sites in both the northern and southern hemispheres. I will summarize the technical and performance aspect of these telescopes, including both their imaging and their anticipated spectroscopic capabilities. But I will also delve into the network organization, including communication among telescopes (to assure that observations are properly carried out), interactions among the institutions and scientists who will use the network (to optimize the scientific returns), and our funding model (which until now has relied entirely on one private donor, but will soon require funding from outside sources, if the full potential of the network is to be achieved).

Eyes on the Universe: The Legacy of the Hubble Space Telescope and Looking to the Future with the James Webb Space Telescope

Science.gov (United States)

Straughn, Amber

2011-01-01

Over the past 20 years the Hubble Space Telescope has revolutionized our understanding of the Universe. Most recently, the complete refurbishment of Hubble in 2009 has given new life to the telescope and the new science instruments have already produced groundbreaking science results, revealing some of the most distant galaxy candidates ever discovered. Despite the remarkable advances in astrophysics that Hubble has provided, the new questions that have arisen demand a new space telescope with new technologies and capabilities. I will present the exciting new technology development and science goals of NASA's James Webb Space Telescope, which is currently being built and tested and will be launched this decade.

MROI Array telescopes: the relocatable enclosure domes

Science.gov (United States)

Marchiori, G.; Busatta, A.; Payne, I.

2016-07-01

The MROI - Magdalena Ridge Interferometer is a project which comprises an array of up to 10 1.4m diameter mirror telescopes arranged in a "Y" configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. EIE GROUP Srl, Venice - Italy, was awarded the contract for the design, the construction and the erection on site of the MROI by the New Mexico Institute of Mining and Technology. The close-pack array of the MROI - including all 10 telescopes, several of which are at a relative distance of less than 8m center to center from each other - necessitated an original design for the Unit Telescope Enclosure (UTE). This innovative design enclosure incorporates a unique dome/observing aperture system to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). The main characteristics of this Relocatable Enclosure Dome are: a Light insulated Steel Structure with a dome made of composites materials (e.g. glass/carbon fibers, sandwich panels etc.), an aperture motorized system for observation, a series of louvers for ventilation, a series of electrical and plants installations and relevant auxiliary equipment. The first Enclosure Dome is now under construction and the completion of the mounting on site id envisaged by the end of 2016. The relocation system utilizes a modified reachstacker (a transporter used to handle freight containers) capable of maneuvering between and around the enclosures, capable of lifting the combined weight of the enclosure with the telescope (30tons), with minimal impacts due to vibrations.

CLIC Telescope optimization with ALLPIX simulation

CERN Document Server

Qi, Wu

2015-01-01

A simulation study of CLIC-EUDET telescope resolution with MIMOSA 26 as reference sensors under DESY (5.6 GeV electron beam) and CERN-SPS (120-180 GeV pion^{-} beam) conditions. During the study, a virtual DUT sensor with cylindrical sensing area was defined and used with ALLPIX software. By changing the configuration of telescope, some results for DESY's setup were found agreeing with the theoretical calculation.

New infrared telescopic observation of Vesta

Science.gov (United States)

Palomba, E.; D'Aversa, E.; Sato, T.; Longobardo, A.; Aoki, S.; Sindoni, G.; Oliva, F.

2017-09-01

In this work we present new telescopic observations of the Vesta asteroid made at the Subaru Telescope by using the COMICS IR spectrometer. We were able to obtain 5 different observations in 5 day, at two different epochs. The obtained spectra do not exhibit Reststrahlen bands and show only weak features attributable to the Christiansen peak and to the transparency feature compatible with a fine grain size regolith.

MAPPING THE POLARIZATION OF THE RADIO-LOUD Ly α NEBULA B3 J2330+3927

Energy Technology Data Exchange (ETDEWEB)

You, Chang; Zabludoff, Ann; Smith, Paul; Jannuzi, Buell [Steward Observatory, University of Arizona, 933 N Cherry Avenue, Tucson, AZ 85721 (United States); Yang, Yujin [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of); Kim, Eunchong; Lee, Myung Gyoon [Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul 88226 (Korea, Republic of); Prescott, Moire K. M. [Department of Astronomy, New Mexico State University, 1320 Frenger Mall, Las Cruces, NM 88003 (United States); Matsuda, Yuichi, E-mail: yyang@kasi.re.kr [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2017-01-10

Ly α nebulae, or “Ly α blobs,” are extended (up to ∼100 kpc), bright (L{sub Lyα}  ≳ 10{sup 43} erg s{sup −1}) clouds of Ly α emitting gas that tend to lie in overdense regions at z  ∼ 2–5. The origin of the Ly α emission remains unknown, but recent theoretical work suggests that measuring the polarization might discriminate among powering mechanisms. Here we present the first narrowband imaging polarimetry of a radio-loud Ly α nebula, B3 J2330+3927, at z = 3.09, with an embedded active galactic nucleus (AGN). The AGN lies near the blob’s Ly α emission peak, and its radio lobes align roughly with the blob’s major axis. With the SPOL polarimeter on the 6.5 m MMT telescope, we map the total (Ly α + continuum) polarization in a grid of circular apertures of a radius of 0.″6 (4.4 kpc), detecting a significant (>2 σ ) polarization fraction P {sub %} in nine apertures and achieving strong upper limits (as low as 2%) elsewhere. P{sub %} increases from <2% at ∼5 kpc from the blob center to 17% at ∼15–25 kpc. The detections are distributed asymmetrically, roughly along the nebula’s major axis. The polarization angles θ are mostly perpendicular to this axis. Comparing the Ly α flux to that of the continuum and conservatively assuming that the continuum is highly polarized (20%–100%) and aligned with the total polarization, we place lower limits on the polarization of the Ly α emission P{sub %,Lyα} ranging from no significant polarization at ∼5 kpc from the blob center to 3%–17% at 10–25 kpc. Like the total polarization, the Ly α polarization detections occur more often along the blob’s major axis.

Large fully retractable telescope enclosures still closable in strong wind

Science.gov (United States)

Bettonvil, Felix C. M.; Hammerschlag, Robert H.; Jägers, Aswin P. L.; Sliepen, Guus

2008-07-01

Two prototypes of fully retractable enclosures with diameters of 7 and 9 m have been built for the high-resolution solar telescopes DOT (Dutch Open Telescope) and GREGOR, both located at the Canary Islands. These enclosures protect the instruments for bad weather and are fully open when the telescopes are in operation. The telescopes and enclosures also operate in hard wind. The prototypes are based on tensioned membrane between movable but stiff bows, which fold together to a ring when opened. The height of the ring is small. The prototypes already survived several storms, with often snow and ice, without any damage, including hurricane Delta with wind speeds up to 68 m/s. The enclosures can still be closed and opened with wind speeds of 20 m/s without any problems or restrictions. The DOT successfully demonstrated the open, wind-flushing concept for astronomical telescopes. It is now widely recognized that also large future telescopes benefit from wind-flushing and retractable enclosures. These telescopes require enclosures with diameters of 30 m until roughly 100 m, the largest sizes for the ELTs (Extreme Large Telescopes), which will be built in the near future. We discuss developments and required technology for the realization of these large sizes.

The Timepix3 Telescope for LHCb Upgrade RD 1 measurements

CERN Document Server

Saunders, Daniel Martin

2016-01-01

The Timepix3 telescope is a high rate, data driven beam telescope created for LHCb upgrade studies, such as sensor performance for prototypes of the vertex locator (VELO) upgrade. When testing VELO prototypes the readout is identical to the telescope, and additionally, a simple way to integrate triggers from other detectors is also provided, allowing tracks to be synchronised offline with other devices under test. Examples of LHCb upgrade detectors which have been qualified with the Timepix3 telescope are the Upstream Tracker (UT), Scintillating Fibres (SciFi), Ring Imaging CHerenkov (RICH), and Time Of internally Reflected CHerenkov light (TORCH). The telescope was installed in the SPS North hall at CERN. It consists of 8 planes with 300 μ m p-on-n silicon sensors read out by Timepix3 ASICs. Tracks measured with the telescope have excellent temporal ( ∼ 1 ns) and spatial resolution ( 2 μ m). The telescope has been operated with a rate of tracks written to disk up to 5 MHz - limited only by conditions at ...

Rise to SUMMIT: the Sydney University Multiple-Mirror Telescope

Science.gov (United States)

Moore, Anna M.; Davis, John

2000-07-01

The Sydney University Multiple Mirror Telescope (SUMMIT) is a medium-sized telescope designed specifically for high resolution stellar spectroscopy. Throughout the design emphasis has been placed on high efficiency at low cost. The telescope consists of four 0.46 m diameter mirrors mounted on a single welded steel frame. Specially designed mirror cells support and point each mirror, allowing accurate positioning of the images on optical fibers located at the foci of the mirrors. Four fibers convey the light to the future location of a high resolution spectrograph away from the telescope in a stable environment. An overview of the commissioning of the telescope is presented, including the guidance and automatic mirror alignment and focussing systems. SUMMIT is located alongside the Sydney University Stellar Interferometer at the Paul Wild Observatory, near Narrabri, Northern New South Wales.

The NASA Spitzer Space Telescope.

Science.gov (United States)

Gehrz, R D; Roellig, T L; Werner, M W; Fazio, G G; Houck, J R; Low, F J; Rieke, G H; Soifer, B T; Levine, D A; Romana, E A

2007-01-01

The National Aeronautics and Space Administration's Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991-2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer's expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/.

Mobile Tracking Systems Using Meter Class Reflective Telescopes

Science.gov (United States)

Sturzenbecher, K.; Ehrhorn, B.

This paper is a discussion on the use of large reflective telescopes on mobile tracking systems with modern instrument control systems. Large optics can be defined as reflective telescopes with an aperture of at least 20 inches in diameter. New carbon composite construction techniques allow for larger, stronger, and lighter telescopes ranging from 240 pounds for a 20 inch, to 800 pounds for a 32 inch, making them ideal for mobile tracking systems. These telescopes have better light gathering capability and produce larger images with greater detail at a longer range than conventional refractive lenses. In a mobile configuration these systems provide the ability to move the observation platform to the optimal location anywhere in the world. Mounting and systems integration - We will discuss how large telescopes can be physically fit to the mobile tracking system and the integration with the tracking systems' digital control system. We will highlight the remote control capabilities. We will discuss special calibration techniques available in a modern instrument control system such as star calibration, calibration of sensors. Tracking Performance - We will discuss the impact of using large telescopes on the performance of the mobile tracking system. We will highlight the capabilities for auto-tracking and sidereal rate tracking in a mobile mount. Large optics performance - We will discuss the advantages of two-mirror Ritchey-Chrétien reflective optics which offer in-focus imaging across the spectrum, from visible to Long Wave Infrared. These zero expansion optics won't lose figure or focus during temperature changes. And the carbon composite telescope tube is thermally inert. The primary mirror is a modern lightweight "dish" mirror for low thermal mass and is center supported/self balancing. Applications - We will discuss Visible - IR Imaging requirements, Optical Rangefinders, and capabilities for special filters to increase resolution in difficult conditions such as

Deep space telescopes

CERN Multimedia

CERN. Geneva

2006-01-01

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

LOBSTER - New Space X-Ray telescopes

International Nuclear Information System (INIS)

Hudec, R.; Pina, L.; Simon, V.; Sveda, L.; Inneman, A.; Semencova, V.; Skulinova, M.

2007-01-01

We discuss the technological and scientific aspects of fully innovative very wide-field X-ray telescopes with high sensitivity. The prototypes of Lobster telescopes designed, developed and tested are very promising, allowing the proposals for space projects with very wide-field Lobster Eye X-ray optics to be considered for the first time. The novel telescopes will monitor the sky with unprecedented sensitivity and angular resolution of order of 1 arcmin. They are expected to contribute essentially to study of various astrophysical objects such as AGN, SNe, Gamma-ray bursts (GRBs), X-ray flashes (XRFs), galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc. For example, the Lobster optics based X-ray All Sky Monitor is capable to detect around 20 GRBs and 8 XRFs yearly and this will surely significantly contribute to the related science

Hubble Space Telescope via the Web

Science.gov (United States)

O'Dea, Christopher P.

The Space Telescope Science Institute (STScI) makes available a wide variety of information concerning the Hubble Space Telescope (HST) via the Space Telescope Electronic Information Service (STEIS). STEIS is accessible via anonymous ftp, gopher, WAIS, and WWW. The information on STEIS includes how to propose for time on the HST, the current status of HST, reports on the scientific instruments, the observing schedule, data reduction software, calibration files, and a set of publicly available images in JPEG, GIF and TIFF format. STEIS serves both the astronomical community as well as the larger Internet community. WWW is currently the most widely used interface to STEIS. Future developments on STEIS are expected to include larger amounts of hypertext, especially HST images and educational material of interest to students, educators, and the general public, and the ability to query proposal status.

Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures

CERN Document Server

Greve, Albert

2010-01-01

Radio telescopes as well as communication antennas operate under the influence of gravity, temperature and wind. Among those, temperature influences may degrade the performance of a radio telescope through transient changes of the focus, pointing, path length and sensitivity, often in an unpredictable way. Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures reviews the design and construction principles of radio telescopes in view of thermal aspects and heat transfer with the variable thermal environment; it explains supporting thermal model calculations and the application and efficiency of thermal protection and temperature control; it presents many measurements illustrating the thermal behaviour of telescopes in the environment of their observatory sites. The book benefits scientists and radio/communication engineers, telescope designers and construction firms as well as telescope operators, observatory staff, but also the observing astronomer who is directly confronted with the t...

Workshop on polarized neutron filters and polarized pulsed neutron experiments

International Nuclear Information System (INIS)

Itoh, Shinichi

2004-07-01

The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

A monolithic silicon detector telescope

International Nuclear Information System (INIS)

Cardella, G.; Amorini, F.; Cabibbo, M.; Di Pietro, A.; Fallica, G.; Franzo, G.; Figuera, P.; Papa, M.; Pappalardo, G.; Percolla, G.; Priolo, F.; Privitera, V.; Rizzo, F.; Tudisco, S.

1996-01-01

An ultrathin silicon detector (1 μm) thick implanted on a standard 400 μm Si-detector has been built to realize a monolithic telescope detector for simultaneous charge and energy determination of charged particles. The performances of the telescope have been tested using standard alpha sources and fragments emitted in nuclear reactions with different projectile-target colliding systems. An excellent charge resolution has been obtained for low energy (less than 5 MeV) light nuclei. A multi-array lay-out of such detectors is under construction to charge identify the particles emitted in reactions induced by low energy radioactive beams. (orig.)

Artificial Intelligence in Autonomous Telescopes

Science.gov (United States)

Mahoney, William; Thanjavur, Karun

2011-03-01

Artificial Intelligence (AI) is key to the natural evolution of today's automated telescopes to fully autonomous systems. Based on its rapid development over the past five decades, AI offers numerous, well-tested techniques for knowledge based decision making essential for real-time telescope monitoring and control, with minimal - and eventually no - human intervention. We present three applications of AI developed at CFHT for monitoring instantaneous sky conditions, assessing quality of imaging data, and a prototype for scheduling observations in real-time. Closely complementing the current remote operations at CFHT, we foresee further development of these methods and full integration in the near future.

The 1.3-m Robotically Controlled Telescope (RCT) at Kitt Peak - A Fifty year old dream Realized: Telescope Characteristics, Current Research and Education Progr

Science.gov (United States)

Guinan, Edward; Gelderman, Richard; Strolger, Louis-Gregory; Carini, Michael T.; McGruder, Charles, III; Campbell, Rachel; Walter, Donald K.; Davis, Donald R.; Tedesco, Edward F.; Engle, Scott G.

2011-03-01

The 1.3 m Robotically Controlled Telescope (RCT) on Kitt Peak has a rich history, including its role as a prototype for remotely controlled telescopes during the 1960s. As such, the RCT could be considered one of the first - Telescopes from Afar. The telescope, originally called the Remotely Controlled Telescope, has been renamed the Robotically Controlled Telescope to reflect the change in operational control and mode of use. The RCT was a conceptual precursor of today's robotic telescopes, but the actual operation of a remotely controlled telescope was technologically premature for its time, and was subsequently manually operated primarily to conduct optical and infrared observations as well being used as a test bed for new spectroscopic and photometric instruments. In 1995 budget constraints forced the closing of the telescope as part of the Kitt Peak National Observatory (KPNO), following nearly 30 years of distinguished service to KPNO. A request for proposals to operate this telescope was issued to the science community. The RCT consortium, lead by Western Kentucky University, was the successful proposer for operation of the telescope. After several difficult years of retrofitting, refurbishing, and automating the telecope and observatory dome, the telescope has returned to routine science operations in November 2009. The RCT has operated smoothly since that time, with no major interruptions. Observations of objects of interest to the consortium partners (including: comets & asteroids, variable & binary stars, exoplanets, supernovae, quasars & blazars) are being routinely obtained and evaluated. One of the distinguishing features of the RCT is that it is an autonomous observatory designed to handle diverse optical imaging and photometry programs. These include being able to automatically deal with a wide range of observing parameters such as -integration time, sky conditions, repetitions, return visits, filters, air mass, non-sidereal objects, transients etc

NASA 3D Models: James Webb Space Telescope

Data.gov (United States)

National Aeronautics and Space Administration — The James Webb Space Telescope (JWST) will be a large infrared telescope with a 6.5-meter primary mirror. The project is working to a 2018 launch date. The JWST will...

PROMPT: Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes

Energy Technology Data Exchange (ETDEWEB)

Reichart, D.; Nysewander, M.; Moran, J. [North Carolina Univ., Chapel Hill (United States). Department of Physics and Astronomy] (and others)

2005-07-15

Funded by $1.2M in grants and donations, we are now building PROMPT at CTIO. When completed in late 2005, PROMPT will consist of six 0.41-meter diameter Ritchey-Chretien telescopes on rapidly slewing mounts that respond to GRB alerts within seconds, when the afterglow is potentially extremely bright. Each mirror and camera coating is being optimized for a different wavelength range and function, including a NIR imager, two red-optimized imager, a blue-optimized imager, an UV-optimized imager, and an optical polarimeter. PROMPT will be able to identify high-redshift events by dropout and distinguish these events from the similar signatures of extinction. In this way, PROMPT will act a distance-finder scope for spectroscopic follow up on the larger 4.1-meter diameter SOAR telescope, which is also located at CTIO. When not chasing GRBs, PROMPT serves broader educational objectives across the state of north Carolina. Enclosure construction and the first two telescopes are now complete and functioning: PROMPT observed Swift's first GRB in December 2004. We upgrade from two to four telescope in February 2005 and from four to six telescopes in mid-2005.

Constraining Line-of-sight Confusion in the Corona Using Linearly Polarized Observations of the Infrared FeXIII 1075nm and SiX 1430nm Emission Lines

Science.gov (United States)

Dima, G. I.; Kuhn, J. R.; Berdyugina, S.

2017-12-01

Measurements of the coronal magnetic field are difficult because of the intrinsically faint emission of coronal plasma and the large spurious background due to the bright solar disk. This work addresses the problem of resolving the confusion of the line-of-sight (LOS) integration through the optically-thin corona being observed. Work on developing new measuring techniques based on single-point inversions using the Hanle effect has already been described (Dima et al. 2016). It is important to develop a technique to assess when the LOS confusion makes comparing models and observations problematic. Using forward integration of synthetic emission through magnetohydrodynamic (MHD) models together with simultaneous linearly polarized observations of the FeXIII 1075nm and SiX 1430nm emission lines allows us to assess LOS confusion. Since the lines are both in the Hanle saturated regime their polarization angles are expected to be aligned as long as the gas is sampling the same magnetic field. If significant contributions to the emission is taking place from different regions along the LOS due to the additive nature of the polarized brightness the measured linear polarization between the two lines will be offset. The size of the resolution element is important for this determination since observing larger coronal regions will confuse the variation along the LOS with that in the plane-of-sky. We also present comparisons between synthetic linearly polarized emission through a global MHD model and observations of the same regions obtained using the 0.5m Scatter-free Observatory for Limb Active Regions and Coronae (SOLARC) telescope located on Haleakala, Maui. This work is being done in preparation for the type of observations that will become possible when the next generation 4m DKIST telescope comes online in 2020.

Modular Orbital Demonstration of an Evolvable Space Telescope (MODEST)

Science.gov (United States)

Baldauf, Brian; Conti, Alberto

2016-01-01

The "Search for Life" via imaging of exoplanets is a mission that requires extremely stable telescopes with apertures in the 10 m to 20 m range. The High Definition Space Telescope (HDST) envisioned for this mission would have an aperture >10 m, which is a larger payload than what can be delivered to space using a single launch vehicle. Building and assembling the mirror segments enabling large telescopes will likely require multiple launches and assembly in space. Space-based telescopes with large apertures will require major changes to system architectures.The Optical Telescope Assembly (OTA) for HDST is a primary mission cost driver. Enabling and affordable solutions for this next generation of large aperture space-based telescope are needed.This paper reports on the concept for the Modular Orbital Demonstration of an Evolvable Space Telescope (MODEST), which demonstrates on-orbit robotic and/or astronaut assembly of a precision optical telescope in space. It will also facilitate demonstration of active correction of phase and mirror shape. MODEST is proposed to be delivered to the ISS using standard Express Logistics Carriers (ELCs) and can mounted to one of a variety of ISS pallets. Post-assembly value includes space, ground, and environmental studies, and a testbed for new instruments. This demonstration program for next generation mirror technology provides significant risk reduction and demonstrates the technology in a six-mirror phased telescope. Other key features of the demonstration include the use of an active primary optical surface with wavefront feedback control that allows on-orbit optimization and demonstration of precise surface control to meet optical system wavefront and stability requirements.MODEST will also be used to evaluate advances in lightweight mirror and metering structure materials such as SiC or Carbon Fiber Reinforced Polymer that have excellent mechanical and thermal properties, e.g. high stiffness, high modulus, high thermal

The Atacama Cosmology Telescope: The Receiver and Instrumentation

Science.gov (United States)

Swetz, D. S.; Ade, P. A. R.; Amiri, M.; Appel, J. W.; Burger, B.; Devlin, M. J.; Dicker, S. R.; Doriese, W. B.; Essinger-Hileman, T.; Fisher, R. P.;

Neutron polarization in polarized 3He targets

International Nuclear Information System (INIS)

Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

1990-01-01

Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

Preliminary Multi-Variable Cost Model for Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Hendrichs, Todd

2010-01-01

Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. This paper reviews the methodology used to develop space telescope cost models; summarizes recently published single variable models; and presents preliminary results for two and three variable cost models. Some of the findings are that increasing mass reduces cost; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and technology development as a function of time reduces cost at the rate of 50% per 17 years.

The ATHENA telescope and optics status

DEFF Research Database (Denmark)

Bavdaz, Marcos; Wille, Eric; Ayre, Mark

2017-01-01

chosen for ATHENA is the Silicon Pore Optics (SPO), which hinges on technology spin-in from the semiconductor industry, and uses a modular approach to produce large effective area lightweight telescope optics with a good angular resolution. Both system studies and the technology developments are guided...... by ESA and implemented in industry, with participation of institutional partners. In this paper an overview of the current status of the telescope optics accommodation and technology development activities is provided....

LYCORIS - A Large Area Strip Telescope

CERN Document Server

Krämer, U; Stanitzki, M; Wu, M

2018-01-01

The LYCORIS Large Area Silicon Strip Telescope for the DESY II Test Beam Facility is presented. The DESY II Test Beam Facility provides elec- tron and positron beams for beam tests of up to 6 GeV. A new telescope with a large 10 × 20 cm2 coverage area based on a 25 μm pitch strip sensor is to be installed within the PCMAG 1 T solenoid. The current state of the system is presented.

When measured spin polarization is not spin polarization

International Nuclear Information System (INIS)

Dowben, P A; Wu Ning; Binek, Christian

2011-01-01

Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO 2 and Cr 2 O 3 illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

The Southern African Large Telescope project

Science.gov (United States)

Buckley, David A. H.; Charles, Philip A.; Nordsieck, Kenneth H.; O'Donoghue, Darragh

The recently completed Southern African Large Telescope (SALT) is a low cost, innovative, 10 m class optical telescope, which began limited scientific operations in August 2005, just 5 years after ground-breaking. This paper describes the design and construction of SALT, including the first-light instruments, SALTICAM and the Robert Stobie Spectrograph (RSS). A rigorous systems engineering approach has ensured that SALT was built to specification, on budget, close to the original schedule and using a relatively small project team. The design trade-offs, which include an active spherical primary mirror array and a fixed altitude telescope with a prime focus tracker, although restrictive in comparison to conventional telescopes, have resulted in an affordable 10 m class telescope for South Africa and its ten partners. Coupled with an initial set of two seeing-limited instruments that concentrate on the UV-visible region (320 - 900 nm) and featuring some niche observational capabilities, SALT will have an ability to conduct some unique science. This includes high time resolution studies, for which some initial results have already been obtained. Many of the versatile modes available with the RSS - which is currently being commissioned - are unique and provide unparallelled opportunities for imaging polarimetry and spectropolarimetry. Likewise, Multi-Object Spectroscopy (with slit masks) and imaging spectroscopy with the RSS, the latter using Fabry-Perot étalons and interference filters, will extend the multiplex advantage over resolutions from 300 to 9000 and fields of view of 2 to 8 arcminutes. Future instrumentation plans include an extremely stable, fibre-fed, high resolution échelle spectrograph and a near-IR (to between 1.5 to 1.7 μm) extension to the RSS. Future development possibilities include phasing the primary mirror and AO. Finally, extrapolations of the SALT/HET designs to ELT proportions remain viable and are surely more affordable than conventional

Twin-Telescope Wettzell (TTW)

Science.gov (United States)

Hase, H.; Dassing, R.; Kronschnabl, G.; Schlüter, W.; Schwarz, W.; Lauber, P.; Kilger, R.

2007-07-01

Following the recommendations made by the VLBI2010 vision report of the IVS, a proposal has been made to construct a Twin Telescope for the Fundamental Station Wettzell in order to meet the future requirements of the next VLBI generation. The Twin Telescope consists of two identical radiotelescopes. It is a project of the Federal Agency for Cartography and Geodesy (BKG). This article summarizes the project and some design ideas for the Twin-Telescope. %ZALMA (2005). Technical Specification for Design, Manufacturing, Transport and Integration on Site of the ALMA ANTENNAS, Doc. ALMA-34.00.00.00.006-BSPE. Behrend, D. (2006). VLBI2010 Antenna Specs, Data sheet. DeBoer, D. (2001). The ATA Offset Gregorian Antenna, ATA Memo #16, February 10. Imbriale, W.A. (2006). Design of a Wideband Radio Telescope, Jet Propulsion Laboratory and S. Weinreb and H. Mandi, California Institute of Technology. Kilger, R. (2007). TWIN-Design studies, Presentation for the IVS board members (internal document),Wettzell. Kronschnabl, G. (2006). Subject: Memo from Bill Petrachenko, E-mail to the Twin-Working Group (in German), July. Lindgren, ETS-Lindgren (2005). The Model 3164-05 Open Boundary Quadridge Horn, Data Sheet. Niell, A., A. Whitney, W. Petrachenko, W. Schlüter, N. Vandenberg, H.Hase, Y. Koyama, C. Ma, H. Schuh, G. Tucari (2006). in: IVS Annual Report 2005, pg. 13-40, NASA/TP-2006-214136, April. Olsson, R., Kildal, P.-S., and Weinreb, S. (2006). IEEE Transactions on Antennas and Propagation, Vol. 54, No. 2, February. Petrachenko, B. (2006). The Case For and Against Multiple Antennas at a Site, IVS Memorandum, 2006-019v01. Petrachenko, B. (2006). IVS Memorandum, 2006-016v01. RFSpin (2004). Double Ridged Waveguide Horn-Model DRH20, Antenna Specifications, Data Sheet. Rohde&Schwarz (2004). SHF Antennas Crossed Log- Periodic Antennas HL024A1/S1, Data Sheet. Rohde&Schwarz (2004). SHF Antennas Log-Periodic Antennas HL050/HL050S1, Data Sheet. Rogers, A.E.E. (2006). Simulations of broadband

Calibration strategies for the Cherenkov Telescope Array

Science.gov (United States)

Gaug, Markus; Berge, David; Daniel, Michael; Doro, Michele; Förster, Andreas; Hofmann, Werner; Maccarone, Maria C.; Parsons, Dan; de los Reyes Lopez, Raquel; van Eldik, Christopher

2014-08-01

The Central Calibration Facilities workpackage of the Cherenkov Telescope Array (CTA) observatory for very high energy gamma ray astronomy defines the overall calibration strategy of the array, develops dedicated hardware and software for the overall array calibration and coordinates the calibration efforts of the different telescopes. The latter include LED-based light pulsers, and various methods and instruments to achieve a calibration of the overall optical throughput. On the array level, methods for the inter-telescope calibration and the absolute calibration of the entire observatory are being developed. Additionally, the atmosphere above the telescopes, used as a calorimeter, will be monitored constantly with state-of-the-art instruments to obtain a full molecular and aerosol profile up to the stratosphere. The aim is to provide a maximal uncertainty of 10% on the reconstructed energy-scale, obtained through various independent methods. Different types of LIDAR in combination with all-sky-cameras will provide the observatory with an online, intelligent scheduling system, which, if the sky is partially covered by clouds, gives preference to sources observable under good atmospheric conditions. Wide-field optical telescopes and Raman Lidars will provide online information about the height-resolved atmospheric extinction, throughout the field-of-view of the cameras, allowing for the correction of the reconstructed energy of each gamma-ray event. The aim is to maximize the duty cycle of the observatory, in terms of usable data, while reducing the dead time introduced by calibration activities to an absolute minimum.

An EUDET/AIDA Pixel Beam Telescope for Detector Development

CERN Document Server

Perrey, Hanno

2013-01-01

A high resolution ($\\sigma 2 \\sim \\mu$) beam telescope based on monolithic active pixel sensors (MAPS) was developed within the EUDET collaboration. The telescope consists of six sensor planes using Mimosa26 MAPS with a pixel pitch of $18.4 \\mu$ and thinned down to $50 \\mu$. The excellent resolution, readout rate and DAQ integration capabilities made the telescope a primary test beam tool for many groups including several CERN based experiments. Within the new European detector infrastructure project AIDA the test beam telescope will be further extended in terms of cooling infrastructure, readout speed and precision. In order to provide a system optimized for the different requirements by the user community, a combination of various pixel technologies is foreseen. In this report the design of this even more flexible telescope with three different pixel technologies (TimePix, Mimosa, ATLAS FE-I4) will be presented. First test beam results with the HitOR signal provided by the FE-I4 integrated into the trigger...

The NIKA2 Large Field-of-View Millimeter Continuum Camera for the 30-M IRAM Telescope

Science.gov (United States)

Monfardini, Alessandro

2018-01-01

We have constructed and deployed a multi-thousands pixels dual-band (150 and 260 GHz, respectively 2mm and 1.15mm wavelengths) camera to image an instantaneous field-of-view of 6.5arc-min and configurable to map the linear polarization at 260GHz. We are providing a detailed description of this instrument, named NIKA2 (New IRAM KID Arrays 2), in particular focusing on the cryogenics, the optics, the focal plane arrays based on Kinetic Inductance Detectors (KID) and the readout electronics. We are presenting the performance measured on the sky during the commissioning runs that took place between October 2015 and April 2017 at the 30-meter IRAM (Institute of Millimetric Radio Astronomy) telescope at Pico Veleta, and preliminary science-grade results.

Simulation of Telescope Detectivity for Geo Survey and Tracking

Science.gov (United States)

Richard, P.

2014-09-01

As the number of space debris on Earths Orbit increases steadily, the need to survey, track and catalogue them becomes of key importance. In this context, CNES has been using the TAROT Telescopes (Rapid Telescopes for Transient Objects owned and operated by CNRS) for several years to conduct studies about space surveillance and tracking. Today, two testbeds of services using the TAROT telescopes are running every night: one for GEO situational awareness and the second for debris tracking. Additionally to the CNES research activity on space surveillance and tracking domain, an operational collision avoidance service for LEO and GEO satellites is in place at CNES for several years. This service named CAESAR (Conjunction Analysis and Evaluation: Alerts and Recommendations) is used by CNES as well as by external customers. As the optical debris tracking testbed based on TAROT telescopes is the first step toward an operational provider of GEO measures that could be used by CAESAR, simulations have been done to help choosing the sites and types of telescopes that could be added in the GEO survey and debris tracking telescope network. One of the distinctive characteristics of the optical observation of space debris compared to traditional astronomic observation is the need to observe objects at low elevations. The two mains reasons for this are the need to observe the GEO belt from non-equatorial sites and the need to observe debris at longitudes far from the telescope longitude. This paper presents the results of simulations of the detectivity for GEO debris of various telescopes and sites, based on models of the GEO belt, the atmosphere and the instruments. One of the conclusions is that clever detection of faint streaks and spread sources by image processing is one of the major keys to improve the detection of debris on the GEO belt.

Thermal emissivity analysis of a GEMINI 8-meter telescopes design

Science.gov (United States)

St. Clair Dinger, Ann

1993-01-01

The GEMINI 8-meter Telescopes Project is designing twin 8-meter telescopes to be located in Hawaii and Chile. The GEMINI telescopes will have interchangeable secondary mirrors for use in the visible and IR. The APART/PADE program is being used to evaluate the effective IR emissivity of the IR configuration plus enclosure as a function of mirror contamination at three IR wavelengths. The goal is to design a telescope whose effective IR emissivity is no more than 2 percent when the mirrors are clean.

Goddard Robotic Telescope (GRT)

Data.gov (United States)

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

Infrared Astronomy Professional Development for K-12 Educators: WISE Telescope

Science.gov (United States)

Borders, Kareen; Mendez, B. M.

2010-01-01

K-12 educators need effective and relevant astronomy professional development. WISE Telescope (Wide-Field Infrared Survey Explorer) and Spitzer Space Telescope Education programs provided an immersive teacher professional development workshop at Arecibo Observatory in Puerto Rico during the summer of 2009. As many common misconceptions involve scale and distance, teachers worked with Moon/Earth scale, solar system scale, and distance of objects in the universe. Teachers built and used basic telescopes, learned about the history of telescopes, explored ground and satellite based telescopes, and explored and worked on models of WISE Telescope. An in-depth explanation of WISE and Spitzer telescopes gave participants background knowledge for infrared astronomy observations. We taught the electromagnetic spectrum through interactive stations. The stations included an overview via lecture and power point, the use of ultraviolet beads to determine ultraviolet exposure, the study of WISE lenticulars and diagramming of infrared data, listening to light by using speakers hooked up to photoreceptor cells, looking at visible light through diffraction glasses and diagramming the data, protocols for using astronomy based research in the classroom, and infrared thermometers to compare environmental conditions around the observatory. An overview of LIDAR physics was followed up by a simulated LIDAR mapping of the topography of Mars. We will outline specific steps for K-12 infrared astronomy professional development, provide data demonstrating the impact of the above professional development on educator understanding and classroom use, and detail future plans for additional K-12 professional development. Funding was provided by WISE Telescope, Spitzer Space Telescope, Starbucks, Arecibo Observatory, the American Institute of Aeronautics and Astronautics, and the Washington Space Grant Consortium.

Low-cost programmable pulse generator for particle telescope calibration

CERN Document Server

Sanchez, S; Seisdedos, M; Meziat, D; Carbajo, M; Medina, J; Bronchalo, E; Peral, L D; Rodríguez-Pacheco, J

1999-01-01

In this paper we present a new calibration system for particle telescopes including multipulse generator and digital controller. The calibration system generates synchronized pulses of variable height for every detector channel on the telescope. The control system is based on a commercial microcontroller linked to a personal computer through an RS-232 bidirectional line. The aim of the device is to perform laboratory calibration of multi-detector telescopes prior to calibration at accelerator. This task includes evaluation of linearity and resolution of each detector channel, as well as coincidence logic. The heights of the pulses sent to the detectors are obtained by Monte Carlo simulation of telescope response to a particle flux of any desired geometry and composition.

Spectroscopic Study of the Polar BS Tri

Science.gov (United States)

Borisov, N. V.; Gabdeev, M. M.; Shimansky, V. V.; Katysheva, N. A.; Shugarov, S. Yu.

2015-11-01

We have analyzed the spectra of the cataclysmic variable BS Tri taken in September 2011 and August 2012 with the 6-m BTA SAO RAS telescope. The object's spectra exhibit a flat continuum with superimposed strong hydrogen Balmer, neutral and ionized helium emission lines. Our analysis of the line profiles has shown that they consist of several components that are formed in the accretion structure and on the irradiated red dwarf surface. The measured radial velocities of one of the components of the line forming in a spot on the red dwarf surface have allowed the parameters of the system to be estimated: M 1 = 0.75 ± 0.02 M ⊙, M 2 = 0.16 ± 0.01 M ⊙, q = 0.21 ± 0.02, and R L2 = 0.18 ± 0.02 R ⊙. The Doppler maps constructed from the emission lines show no disk accretion, defining the system as a polar.

The Green Bank Telescope: A radio telescope for the twenty-first century: Final proposal June 1989

International Nuclear Information System (INIS)

Anon.

1989-01-01

The scientific goals, design, and projected performance of a 100-m-aperture steerable radio telescope to be built at Green Bank, WV are discussed in a proposal to the NSF. The goals considered include observations of pulsars, stars and the solar system; studies of Galactic and extragalactic H I, spectroscopic studies, measurements of continuum radiation; and VLBI observations. Detailed attention is given to the antenna, electronics, control and monitor system, data processing, operational factors, the telescope site, and cost estimates. Drawings, diagrams, sample images, and tables of numerical data are provided

The SPIRIT Telescope Initiative: six years on

Science.gov (United States)

Luckas, Paul

2017-06-01

Now in its sixth year of operation, the SPIRIT initiative remains unique in Australia, as a robust web-enabled robotic telescope initiative funded for education and outreach. With multiple modes of operation catering for a variety of usage scenarios and a fully supported education program, SPIRIT provides free access to contemporary astronomical tools for students and educators in Western Australia and beyond. The technical solution itself provides an excellent model for low cost robotic telescope installations, and the education program has evolved over time to include a broad range of student experiences-from engagement activities to authentic science. This paper details the robotic telescope solution, student interface and educational philosophy, summarises achievements and lessons learned and examines the possibilities for future enhancement including spectroscopy.

Development of a Multivariable Parametric Cost Analysis for Space-Based Telescopes

Science.gov (United States)

Dollinger, Courtnay

2011-01-01

Over the past 400 years, the telescope has proven to be a valuable tool in helping humankind understand the Universe around us. The images and data produced by telescopes have revolutionized planetary, solar, stellar, and galactic astronomy and have inspired a wide range of people, from the child who dreams about the images seen on NASA websites to the most highly trained scientist. Like all scientific endeavors, astronomical research must operate within the constraints imposed by budget limitations. Hence the importance of understanding cost: to find the balance between the dreams of scientists and the restrictions of the available budget. By logically analyzing the data we have collected for over thirty different telescopes from more than 200 different sources, statistical methods, such as plotting regressions and residuals, can be used to determine what drives the cost of telescopes to build and use a cost model for space-based telescopes. Previous cost models have focused their attention on ground-based telescopes due to limited data for space telescopes and the larger number and longer history of ground-based astronomy. Due to the increased availability of cost data from recent space-telescope construction, we have been able to produce and begin testing a comprehensive cost model for space telescopes, with guidance from the cost models for ground-based telescopes. By separating the variables that effect cost such as diameter, mass, wavelength, density, data rate, and number of instruments, we advance the goal to better understand the cost drivers of space telescopes.. The use of sophisticated mathematical techniques to improve the accuracy of cost models has the potential to help society make informed decisions about proposed scientific projects. An improved knowledge of cost will allow scientists to get the maximum value returned for the money given and create a harmony between the visions of scientists and the reality of a budget.

A focal plane detector design for a wide-band Laue-lens telescope

DEFF Research Database (Denmark)

Caroli, E.; Auricchio, N.; Amati, L.

2005-01-01

, and the detection of nuclear and annihilation lines. Recently the development of high energy Laue lenses with broad energy bandpasses from 60 to 600 keV have been proposed for a Hard X ray focusing Telescope (HAXTEL) in order to study the X-ray continuum of celestial sources. The required focal plane detector...... should have high detection efficiency over the entire operative range, a spatial resolution of about 1 mm, an energy resolution of a few keV at 500 keV and a sensitivity to linear polarization. We describe a possible configuration of the focal plane detector based on several CdTe/CZT pixelated layers......The energy range above 60 keV is important for the study of many open problems in high energy astrophysics such as the role of Inverse Compton with respect to synchrotron or thermal processes in GRBs, non thermal mechanisms in SNR, the study of the high energy cut-offs in AGN spectra...

Software framework for automatic learning of telescope operation

Science.gov (United States)

Rodríguez, Jose A.; Molgó, Jordi; Guerra, Dailos

2016-07-01

The "Gran Telescopio de Canarias" (GTC) is an optical-infrared 10-meter segmented mirror telescope at the ORM observatory in Canary Islands (Spain). The GTC Control System (GCS) is a distributed object and component oriented system based on RT-CORBA and it is responsible for the operation of the telescope, including its instrumentation. The current development state of GCS is mature and fully operational. On the one hand telescope users as PI's implement the sequences of observing modes of future scientific instruments that will be installed in the telescope and operators, in turn, design their own sequences for maintenance. On the other hand engineers develop new components that provide new functionality required by the system. This great work effort is possible to minimize so that costs are reduced, especially if one considers that software maintenance is the most expensive phase of the software life cycle. Could we design a system that allows the progressive assimilation of sequences of operation and maintenance of the telescope, through an automatic self-programming system, so that it can evolve from one Component oriented organization to a Service oriented organization? One possible way to achieve this is to use mechanisms of learning and knowledge consolidation to reduce to the minimum expression the effort to transform the specifications of the different telescope users to the operational deployments. This article proposes a framework for solving this problem based on the combination of the following tools: data mining, self-Adaptive software, code generation, refactoring based on metrics, Hierarchical Agglomerative Clustering and Service Oriented Architectures.

Optical design of a Michelson wide-field multiple-aperture telescope

Science.gov (United States)

Cassaing, Frederic; Sorrente, Beatrice; Fleury, Bruno; Laubier, David

2004-02-01

Multiple-Aperture Optical Telescopes (MAOTs) are a promising solution for very high resolution imaging. In the Michelson configuration, the instrument is made of sub-telescopes distributed in the pupil and combined by a common telescope via folding periscopes. The phasing conditions of the sub-pupils lead to specific optical constraints in these subsystems. The amplitude of main contributors to the wavefront error (WFE) is given as a function of high level requirements (such as field or resolution) and free parameters, mainly the sub-telescope type, magnification and diameter. It is shown that for the periscopes, the field-to-resolution ratio is the main design driver and can lead to severe specifications. The effect of sub-telescopes aberrations on the global WFE can be minimized by reducing their diameter. An analytical tool for the MAOT design has been derived from this analysis, illustrated and validated in three different cases: LEO or GEO Earth observation and astronomy with extremely large telescopes. The last two cases show that a field larger than 10 000 resolution elements can be covered with a very simple MAOT based on Mersenne paraboloid-paraboloid sub-telescopes. Michelson MAOTs are thus a solution to be considered for high resolution wide-field imaging, from space or ground.

NST: Thermal Modeling for a Large Aperture Solar Telescope

Science.gov (United States)

Coulter, Roy

2011-05-01

Late in the 1990s the Dutch Open Telescope demonstrated that internal seeing in open, large aperture solar telescopes can be controlled by flushing air across the primary mirror and other telescope structures exposed to sunlight. In that system natural wind provides a uniform air temperature throughout the imaging volume, while efficiently sweeping heated air away from the optics and mechanical structure. Big Bear Solar Observatory's New Solar Telescope (NST) was designed to realize that same performance in an enclosed system by using both natural wind through the dome and forced air circulation around the primary mirror to provide the uniform air temperatures required within the telescope volume. The NST is housed in a conventional, ventilated dome with a circular opening, in place of the standard dome slit, that allows sunlight to fall only on an aperture stop and the primary mirror. The primary mirror is housed deep inside a cylindrical cell with only minimal openings in the side at the level of the mirror. To date, the forced air and cooling systems designed for the NST primary mirror have not been implemented, yet the telescope regularly produces solar images indicative of the absence of mirror seeing. Computational Fluid Dynamics (CFD) analysis of the NST primary mirror system along with measurements of air flows within the dome, around the telescope structure, and internal to the mirror cell are used to explain the origin of this seemingly incongruent result. The CFD analysis is also extended to hypothetical systems of various scales. We will discuss the results of these investigations.

Chinese large solar telescopes site survey

Science.gov (United States)

Liu, Yu

2017-04-01

In order to observe the solar surface with unprecedentedly higher resolution, Chinse solar physics society decided to launch their solar site survey project in 2010 as the first step to look for the best candidate sites for the Chinese next-generation large-aperture solar telescopes, i.e., the 5-8 meter Chinese Giant Solar Telescope, and the 1 meter level coronagraph. We have built two long-term monitoring sites in Daocheng, with altitudes of around 4800 meters above the sea level located in the large Shangri-La mountain area, and we have collected systematic site data since 2014. Clear evidence, including the key parameters of seeing factor, sky brightness and water vapor content, has indicated that the large Shangri-La area owns the potential conditions of excellent seeing level and sufficient amount of clear-sky hours suitable for developing large solar telescopes. We will review the site survey progress and present the preliminary statistical results in this talk.

Observatories and Telescopes of Modern Times

Science.gov (United States)

Leverington, David

2016-11-01

Preface; Part I. Optical Observatories: 1. Palomar Mountain Observatory; 2. The United States Optical Observatory; 3. From the Next Generation Telescope to Gemini and SOAR; 4. Competing primary mirror designs; 5. Active optics, adaptive optics and other technical innovations; 6. European Northern Observatory and Calar Alto; 7. European Southern Observatory; 8. Mauna Kea Observatory; 9. Australian optical observatories; 10. Mount Hopkins' Whipple Observatory and the MMT; 11. Apache Point Observatory; 12. Carnegie Southern Observatory (Las Campanas); 13. Mount Graham International Optical Observatory; 14. Modern optical interferometers; 15. Solar observatories; Part II. Radio Observatories: 16. Australian radio observatories; 17. Cambridge Mullard Radio Observatory; 18. Jodrell Bank; 19. Early radio observatories away from the Australian-British axis; 20. The American National Radio Astronomy Observatory; 21. Owens Valley and Mauna Kea; 22. Further North and Central American observatories; 23. Further European and Asian radio observatories; 24. ALMA and the South Pole; Name index; Optical observatory and telescope index; Radio observatory and telescope index; General index.

The Swift Ultra-Violet/Optical Telescope

International Nuclear Information System (INIS)

Roming, Peter; Hunsberger, S.D.; Nousek, John; Mason, Keith

2001-01-01

The Ultra-Violet/Optical Telescope (UVOT) provides the Swift Gamma-Ray Burst Explorer with the capability of quickly detecting and characterizing the optical and ultraviolet properties of gamma ray burst counterparts. The UVOT design is based on the design of the Optical Monitor on XMM-Newton. It is a Ritchey-Chretien telescope with microchannel plate intensified charged-coupled devices (MICs) that deliver sub-arcsecond imaging. These MICs are photon-counting devices, capable of detecting low intensity signal levels. When flown above the atmosphere, the UVOT will have the sensitivity of a 4m ground based telescope, attaining a limiting magnitude of 24 for a 1000 second observation in the white light filter. A rotating filter wheel allows sensitive photometry in six bands spanning the UV and visible, which will provide photometric redshifts of objects in the 1-3.5z range. For bright counterparts, such as the 9th magnitude GRB990123, or for fainter objects down to 17th magnitude, two grisms provide low-resolution spectroscopy

Deployable reflector configurations. [for space telescope

Science.gov (United States)

Meinel, A. B.; Meinel, M. P.; Woolf, N. J.

1983-01-01

Both the theoretical reasons for considering a non-circular format for the Large Deployable Reflector, and a potentially realizable concept for such a device, are discussed. The optimum systems for diffraction limited telescopes with incoherent detection have either a single filled aperture, or two such apertures as an interferometer to synthesize a larger aperture. For a single aperture of limited area, a reflector in the form of a slot can be used to give increased angular resolution. It is shown how a 20 x 8 meter telescope can be configured to fit the Space Shuttle bay, and deployed with relatively simple operations. The relationship between the sunshield design and the inclination of the orbit is discussed. The possible use of the LDR as a basic module to permit the construction of supergiant space telescopes and interferometers both for IR/submm studies and for the entire ultraviolet through mm wave spectral region is discussed.

Template analysis for the MAGIC telescopes

Energy Technology Data Exchange (ETDEWEB)

Menzel, Uta [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: MAGIC-Collaboration

2016-07-01

The MAGIC telescopes are two 17-m-diameter Imaging Air Cherenkov Telescopes located on the Canary island of La Palma. They record the Cherenkov light from air showers induced by very high energy photons. The current data analysis uses a parametrization of the two shower images (including Hillas parameters) to determine the characteristics of the primary particle. I am implementing an advanced analysis method that compares shower images on a pixel basis with template images based on Monte Carlo simulations. To reduce the simulation effort the templates contain only pure shower images that are convolved with the telescope response later in the analysis. The primary particle parameters are reconstructed by maximizing the likelihood of the template. By using all the information available in the shower images, the performance of MAGIC is expected to improve. In this presentation I will explain the general idea of a template-based analysis and show the first results of the implementation.

Exploring Galileo's Telescope

Science.gov (United States)

Straulino, Samuele; Terzuoli, Alessandra

2010-01-01

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

Long wavelength infrared camera (LWIRC): a 10 micron camera for the Keck Telescope

Energy Technology Data Exchange (ETDEWEB)

Wishnow, E.H.; Danchi, W.C.; Tuthill, P.; Wurtz, R.; Jernigan, J.G.; Arens, J.F.

1998-05-01

The Long Wavelength Infrared Camera (LWIRC) is a facility instrument for the Keck Observatory designed to operate at the f/25 forward Cassegrain focus of the Keck I telescope. The camera operates over the wavelength band 7-13 {micro}m using ZnSe transmissive optics. A set of filters, a circular variable filter (CVF), and a mid-infrared polarizer are available, as are three plate scales: 0.05``, 0.10``, 0.21`` per pixel. The camera focal plane array and optics are cooled using liquid helium. The system has been refurbished with a 128 x 128 pixel Si:As detector array. The electronics readout system used to clock the array is compatible with both the hardware and software of the other Keck infrared instruments NIRC and LWS. A new pre-amplifier/A-D converter has been designed and constructed which decreases greatly the system susceptibility to noise.

Payload maintenance cost model for the space telescope

Science.gov (United States)

White, W. L.

1980-01-01

An optimum maintenance cost model for the space telescope for a fifteen year mission cycle was developed. Various documents and subsequent updates of failure rates and configurations were made. The reliability of the space telescope for one year, two and one half years, and five years were determined using the failure rates and configurations. The failure rates and configurations were also used in the maintenance simulation computer model which simulate the failure patterns for the fifteen year mission life of the space telescope. Cost algorithms associated with the maintenance options as indicated by the failure patterns were developed and integrated into the model.

Origins Space Telescope

Science.gov (United States)

Cooray, Asantha; Origins Space Telescope Study Team

2018-01-01

The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its spectrographs will enable 3D surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu. This presentation will provide a summary of the OST STDT, our completed first mission concept and an introduction to the second concept that will be studied at the study center in 2018. This presentation will also summarize key science drivers and the key study milestones between 2018 and 2020.

Chromospheric telescope of Baikal Astrophysical Observatory. New light

Directory of Open Access Journals (Sweden)

Skomorovsky V.I.

2016-06-01

Full Text Available A chromospheric telescope is an important instrument for synoptic observations and solar research. After several decades of observations with the chromospheric telescope at the Baikal Astrophysical Observatory, a need arose to improve the characteristics of this telescope and filter. A new reimaging lens to produce full-disk solar images 18 mm in diameter at the CCD camera Hamamatsu C-124 with a 36×24 mm detector (4000×2672 pixels was designed and manufactured to replace the out-of-operation 50×50 mm Princeton Instruments camera. A contrast interference blocking filter and new calcite and quartz crystal plates were made and installed instead of damaged ones in the Hα birefringent filter (BF, manufactured by Bernhard Hallе Nachfl. The optical immersion in the filter was changed. All telescope optics was cleaned and adjusted. We describe for the first time the design features and their related BF passband tuning. The wavefront interferograms of optical elements and telescope as a whole show that the wavefront distortion of the optical path is within 0.25 λ. The BF and prefilter spectral parameters provide high-contrast monochromatic images. Besides, we give examples of solar chromospheric images in the Hα line core and wing.

The telescopic tourist's guide to the Moon

CERN Document Server

May, Andrew

2017-01-01

Whether you’re interested in visiting Apollo landing sites or the locations of classic sci-fi movies, this is the tourist guide for you! This tourist guide has a twist – it is a guide to a whole different world, which you can visit from the comfort of your backyard with the aid of nothing more sophisticated than an inexpensive telescope. It tells you the best times to view the Moon, the most exciting sights to look out for, and the best equipment to use, allowing you to snap stunning photographs as well as view the sights with your own eyes. Have you ever been inspired by stunning images from the Hubble telescope, or the magic of sci-fi special effects, only to look through a small backyard telescope at the disappointing white dot of a planet or faint blur of a galaxy? Yet the Moon is different. Seen through even a relatively cheap telescope, it springs into life like a real place, with mountains and valleys and rugged craters. With a bit of imagination, you can even picture yourself as a sightseeing visi...

Research on generating various polarization-modes in polarized illumination system

Science.gov (United States)

Huang, Jinping; Lin, Wumei; Fan, Zhenjie

2013-08-01

With the increase of the numerical aperture (NA), the polarization of light affects the imaging quality of projection lens more significantly. On the contrary, according to the mask pattern, the resolution of projection lens can be improved by using the polarized illumination. That is to say, using the corresponding polarized beam (or polarization-mode) along with the off-axis illumination will improve the resolution and the imaging quality of the of projection lens. Therefore, the research on the generation of various polarization modes and its conversion methods become more and more important. In order to realize various polarization modes in polarized illumination system, after read a lot of references, we provide a way that fitting for the illumination system with the wavelength of 193nm.Six polarization-modes and a depolarized mode are probably considered. Wave-plate stack is used to generate linearly polarization-mode, which have a higher degree polarization. In order to generate X-Y and Y-X polarization mode, the equipment consisting of four sectors of λ/2 wave plate was used. We combined 16 sectors of λ/2 wave plate which have different orientations of the "slow" axis to generate radial and azimuthal polarization. Finally, a multi-polarization control device was designed. Using the kind of multi-polarization control device which applying this method could help to choose the polarization modes conveniently and flexibility for the illumination system.

Polarization properties of linearly polarized parabolic scaling Bessel beams

Energy Technology Data Exchange (ETDEWEB)

Guo, Mengwen; Zhao, Daomu, E-mail: zhaodaomu@yahoo.com

2016-10-07

The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

Development of the optical system for the SST-1M telescope of the Cherenkov Telescope Array observatory

CERN Document Server

Ostrowski, Michael; Błocki, J.; Bogacz, L.; Bulik, T.; Cadoux, F.; Christov, A.; Curyło, M.; della Volpe, D.; Dyrda, M.; Favre, Y.; Frankowski, A.; Grudnik, Ł.; Grudzińska, M.; Heller, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandat, D.; Marszałek, A.; Michałowski, J.; Moderski, R.; Montaruli, T.; Neronov, A.; Niemiec, J.; Paśko, P.; Pech, M.; Porcelli, A.; Prandini, E.; Pueschel, E.; Rajda, P.; Rameez, M.; Schioppa, E. jr; Schovanek, P.; Skowron, K.; Sliusar, V.; Sowiński, M.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Toscano, S.; Troyano Pujadas, I.; Walter, R.; Wiȩcek, M.; Zagdański, A.; Ziȩtara, K.; Żychowski, P.; Barciński, T.; Karczewski, M.; Kukliński, J. Nicolau; Płatos, Ł.; Rataj, M.; Wawer, P.; Wawrzaszek, R.

2016-01-01

The prototype of a Davies-Cotton small size telescope (SST-1M) has been designed and developed by a consortium of Polish and Swiss institutions and proposed for the Cherenkov Telescope Array (CTA) observatory. The main purpose of the optical system is to focus the Cherenkov light emitted by extensive air showers in the atmosphere onto the focal plane detectors. The main component of the system is a dish consisting of 18 hexagonal mirrors with a total effective collection area of 6.47 m2 (including the shadowing and estimated mirror reflectivity). Such a solution was chosen taking into account the analysis of the Cherenkov light propagation and based on optical simulations. The proper curvature and stability of the dish is ensured by the mirror alignment system and the isostatic interface to the telescope structure. Here we present the design of the optical subsystem together with the performance measurements of its components.

The Hubble Space Telescope from concept to success

CERN Document Server

Shayler, David J

2016-01-01

The highly successful Hubble Space Telescope was meant to change our view and understanding of the universe. Within weeks of its launch in 1990, however, the space community was shocked to find out that the primary mirror of the telescope was flawed. It was only the skills of scientists and engineers on the ground and the daring talents of astronauts sent to service the telescope in December 1993 that saved the mission. For over two decades NASA had developed the capabilities to service a payload in orbit. This involved numerous studies and the creation of a ground-based infrastructure to support the challenging missions. Unique tools and EVA hardware supported the skills developed in crew training that then enabled astronauts to complete a demanding series of spacewalks. Drawing upon first hand interviews with those closely involved in the project over thirty years ago this story explains the development of the servicing mission concept and the hurdles that had to be overcome to not only launch the telescope...

Polarized nuclear target based on parahydrogen induced polarization

OpenAIRE

Budker, D.; Ledbetter, M. P.; Appelt, S.; Bouchard, L. S.; Wojtsekhowski, B.

2012-01-01

We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ($\\sim$100 Hz) polarization reversal, and operation with large intensity of an electron beam.

3.6-m Devasthal Optical Telescope Project: Completion and first results

Science.gov (United States)

Kumar, Brijesh; Omar, Amitesh; Maheswar, Gopinathan; Pandey, Anil Kumar; Sagar, Ram; Uddin, Wahab; Sanwal, Basant Ballabh; Bangia, Tarun; Kumar, Tripurari Satyanarayana; Yadav, Shobhit; Sahu, Sanjit; Pant, Jayshreekar; Reddy, Bheemireddy Krishna; Gupta, Alok Chandra; Chand, Hum; Pandey, Jeewan Chandra; Joshi, Mohit Kumar; Jaiswar, Mukeshkuma; Nanjappa, Nandish; Purushottam; Yadav, Rama Kant Singh; Sharma, Saurabh; Pandey, Shashi Bhushan; Joshi, Santosh; Joshi, Yogesh Chandra; Lata, Sneh; Mehdi, Biman Jyoti; Misra, Kuntal; Singh, Mahendra

2018-04-01

We present an update on the 3.6-m aperture optical telescope, which has been installed at Devasthal in the year 2016. In this paper, a brief overview of installation activities at site and first results are presented. The 3.6-m Devasthal Optical Telescope project was initiated in 2007 by the Aryabhatta Research Institute of Observational Sciences (ARIES; Nainital, India) in partnership with Belgium. The telescope has Ritchey-Chretien optics, an alt-azimuth mount, an active control of the primary and a corrected science field of view of 30' at the Cassegrain focus. The construction of the telescope enclosure building was completed in June 2014 and after successful installation of the telescope. The first engineering light was obtained on 22 March 2015. The on-sky performance of the telescope was carried out till February 2016.

Stray light field dependence for large astronomical space telescopes

Science.gov (United States)

Lightsey, Paul A.; Bowers, Charles W.

2017-09-01

Future large astronomical telescopes in space will have architectures that expose the optics to large angular extents of the sky. Options for reducing stray light coming from the sky range from enclosing the telescope in a tubular baffle to having an open telescope structure with a large sunshield to eliminate solar illumination. These two options are considered for an on-axis telescope design to explore stray light considerations. A tubular baffle design will limit the sky exposure to the solid angle of the cone in front of the telescope set by the aspect ratio of the baffle length to Primary Mirror (PM) diameter. Illumination from this portion of the sky will be limited to the PM and structures internal to the tubular baffle. Alternatively, an open structure design will allow a large portion of the sky to directly illuminate the PM and Secondary Mirror (SM) as well as illuminating sunshield and other structure surfaces which will reflect or scatter light onto the PM and SM. Portions of this illumination of the PM and SM will be scattered into the optical train as stray light. A Radiance Transfer Function (RTF) is calculated for the open architecture that determines the ratio of the stray light background radiance in the image contributed by a patch of sky having unit radiance. The full 4π steradian of sky is divided into a grid of patches, with the location of each patch defined in the telescope coordinate system. By rotating the celestial sky radiance maps into the telescope coordinate frame for a given pointing direction of the telescope, the RTF may be applied to the sky brightness and the results integrated to get the total stray light from the sky for that pointing direction. The RTF data generated for the open architecture may analyzed as a function of the expanding cone angle about the pointing direction. In this manner, the open architecture data may be used to directly compare to a tubular baffle design parameterized by allowed cone angle based on the

Sidereal semi-diurnal variation observed at high zenith angles at Mawson, 1968-1984, and the polarity of the solar main field

International Nuclear Information System (INIS)

Jacklyn, R.M.; Duldig, M.L.

1985-01-01

High zenith-angle North/South telescopes viewing equatorially and at midlatitudes through 40 MWE of atmosphere have been operating at Mawson since early 1968. It is evident that a sidereal semi-diurnal component of galactic origin has been observed, over and above a possible spurious component proposed by Nagashima, arising from a bi-directional component of the solar anisotropy. Although a very pronounced reduction in the semi-diurnal galactic response followed the reversal of polarity of the solar main field during 1969 to 1971, so far the observations indicate that there has been no recurrence of a larger galactic response following the reversal of polarity around 1981. The possible role of the latitudional extent lambda omicron of the wavy neutral sheet is discussed

The TOTEM GEM Telescope (T2) at the LHC

International Nuclear Information System (INIS)

Quinto, M.; Berretti, M.; David, E.; Garcia, F.; Greco, V.; Heino, J.; Hilden, T.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Oliveri, E.; Ropelewski, L.; Scribano, A.; Turini, N.; Stenis, M. van

2011-01-01

The TOTEM T2 telescope will measure inelastically produced charged particles in the forward region of the LHC Interaction Point 5. Each arm of the telescope consists in a set of 20 triple-GEM (Gas Electron Multiplier) detectors with tracking and trigger capabilities. The GEM technology has been considered for the design of TOTEM very forward T2 telescopes thanks to its characteristics: large active areas, good position and timing resolution, excellent rate capability and radiation hardness. Each of the four T2 half arms has been fully assembled and equipped with electronics at CERN and systematically tested in the SPS beam line H8 in 2008/09. After some optimization, the operation of the GEM chambers was fully satisfactory and the T2 telescopes were installed and commissioned in their final positions at the LHC interaction point. During the first LHC run (December 2009) the T2 telescopes have collected data, at 900 GeV and 2.36 TeV. We will present here the performances of the detector and the preliminary results obtained using the data collected.

The TOTEM GEM Telescope (T2) at the LHC

Energy Technology Data Exchange (ETDEWEB)

Quinto, M. [INFN Sezione di Bari, Via E.Orabona n 4, 70126 Bari (Italy); Berretti, M. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); David, E. [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland); Garcia, F. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Greco, V. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Heino, J.; Hilden, T.; Kurvinen, K. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Lami, S. [INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Latino, G. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Lauhakangas, R. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Oliveri, E. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Ropelewski, L. [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland); Scribano, A.; Turini, N. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Stenis, M. van [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland)

2011-06-15

The TOTEM T2 telescope will measure inelastically produced charged particles in the forward region of the LHC Interaction Point 5. Each arm of the telescope consists in a set of 20 triple-GEM (Gas Electron Multiplier) detectors with tracking and trigger capabilities. The GEM technology has been considered for the design of TOTEM very forward T2 telescopes thanks to its characteristics: large active areas, good position and timing resolution, excellent rate capability and radiation hardness. Each of the four T2 half arms has been fully assembled and equipped with electronics at CERN and systematically tested in the SPS beam line H8 in 2008/09. After some optimization, the operation of the GEM chambers was fully satisfactory and the T2 telescopes were installed and commissioned in their final positions at the LHC interaction point. During the first LHC run (December 2009) the T2 telescopes have collected data, at 900 GeV and 2.36 TeV. We will present here the performances of the detector and the preliminary results obtained using the data collected.

VLBI observations with the Kunming 40-meter radio telescope

International Nuclear Information System (INIS)

Hao Longfei; Wang Min; Yang Jun

2010-01-01

The Kunming 40-meter radio telescope is situated in the yard of the Yunnan Astronomical Observatory (Longitude: 102.8 0 East, Latitude: 25.0 0 North) and saw its first light in 2006 May. The Kunming station successfully joined the VLBI tracking of China's first lunar probe 'Chang'E-1 together with the other Chinese telescopes: the Beijing Miyun 50-meter radio telescope, Urumqi Nanshan 25-meter radio telescope, and Shanghai Sheshan 25-meter radio telescope, and received the downlinked scientific data together with the Miyun station from October of 2007 to March of 2009. We give an introduction to the new Chinese VLBI facility and investigate its potential applications. Due to its location, the Kunming station can significantly improve the u - v coverage of the European VLBI Network (EVN), in particular, in long baseline observations. We also report the results of the first EVN fringe-test experiment of N09SX1 with the Kunming station. The first fringes in the European telescopes were successfully detected at 2.3 GHz with the ftp-transferred data on 2009 June 17. From scheduling the observations to performing the post correlations, the Kunming station shows its good compatibility to work with the EVN. The imaging result of the extended source 1156+295 further demonstrates that the Kunming station greatly enhances the EVN performance. (research papers)

Design Evolution of the Wide Field Infrared Survey Telescope Using Astrophysics Focused Telescope Assets (WFIRST-AFTA) and Lessons Learned

Science.gov (United States)

Peabody, Hume L.; Peters, Carlton V.; Rodriguez-Ruiz, Juan E.; McDonald, Carson S.; Content, David A.; Jackson, Clifton E.

2015-01-01

The design of the Wide Field Infrared Survey Telescope using Astrophysics Focused Telescope Assets (WFIRST-AFTA) continues to evolve as each design cycle is analyzed. In 2012, two Hubble sized (2.4 m diameter) telescopes were donated to NASA from elsewhere in the Federal Government. NASA began investigating potential uses for these telescopes and identified WFIRST as a mission to benefit from these assets. With an updated, deeper, and sharper field of view than previous design iterations with a smaller telescope, the optical designs of the WFIRST instruments were updated and the mechanical and thermal designs evolved around the new optical layout. Beginning with Design Cycle 3, significant analysis efforts yielded a design and model that could be evaluated for Structural-Thermal-Optical-Performance (STOP) purposes for the Wide Field Imager (WFI) and provided the basis for evaluating the high level observatory requirements. Development of the Cycle 3 thermal model provided some valuable analysis lessons learned and established best practices for future design cycles. However, the Cycle 3 design did include some major liens and evolving requirements which were addressed in the Cycle 4 Design. Some of the design changes are driven by requirements changes, while others are optimizations or solutions to liens from previous cycles. Again in Cycle 4, STOP analysis was performed and further insights into the overall design were gained leading to the Cycle 5 design effort currently underway. This paper seeks to capture the thermal design evolution, with focus on major design drivers, key decisions and their rationale, and lessons learned as the design evolved.

Development of the Phase-up Technology of the Radio Telescopes: 6.7 GHz Methanol Maser Observations with Phased Hitachi 32 m and Takahagi 32 m Radio Telescopes

Science.gov (United States)

Takefuji, K.; Sugiyama, K.; Yonekura, Y.; Saito, T.; Fujisawa, K.; Kondo, T.

2017-11-01

For the sake of high-sensitivity 6.7 GHz methanol maser observations, we developed a new technology for coherently combining the two signals from the Hitachi 32 m radio telescope and the Takahagi 32 m radio telescope of the Japanese Very long baseline interferometer Network (JVN), where the two telescopes were separated by about 260 m. After the two telescopes were phased as a twofold larger single telescope, the mean signal-to-noise ratio (S/N) of the 6.7 GHz methanol masers observed by the phased telescopes was improved to 1.254-fold higher than that of the single dish, through a very long baseline interferometry (VLBI) experiment on the 50 km baseline of the Kashima 34 m telescope and the 1000 km baseline of the Yamaguchi 32 m telescope. Furthermore, we compared the S/Ns of the 6.7 GHz maser spectra for two methods. One is a VLBI method and the other is the newly developed digital position switching that is a similar technology to that used in noise-canceling headphones. Finally, we confirmed that the mean S/N of method of the digital position switching (ON-OFF) was 1.597-fold higher than that of the VLBI method.

DESTINY, The Dark Energy Space Telescope

Science.gov (United States)

Pasquale, Bert A.; Woodruff, Robert A.; Benford, Dominic J.; Lauer, Tod

2007-01-01

We have proposed the development of a low-cost space telescope, Destiny, as a concept for the NASA/DOE Joint Dark Energy Mission. Destiny is a 1.65m space telescope, featuring a near-infrared (0.85-1.7m) survey camera/spectrometer with a moderate flat-field field of view (FOV). Destiny will probe the properties of dark energy by obtaining a Hubble diagram based on Type Ia supernovae and a large-scale mass power spectrum derived from weak lensing distortions of field galaxies as a function of redshift.

Polarization modeling and predictions for DKIST part 3: focal ratio and thermal dependencies of spectral polarization fringes and optic retardance

Science.gov (United States)

Harrington, David M.; Sueoka, Stacey R.

2018-01-01

Data products from high spectral resolution astronomical polarimeters are often limited by fringes. Fringes can skew derived magnetic field properties from spectropolarimetric data. Fringe removal algorithms can also corrupt the data if the fringes and object signals are too similar. For some narrow-band imaging polarimeters, fringes change the calibration retarder properties and dominate the calibration errors. Systems-level engineering tools for polarimetric instrumentation require accurate predictions of fringe amplitudes, periods for transmission, diattenuation, and retardance. The relevant instabilities caused by environmental, thermal, and optical properties can be modeled and mitigation tools developed. We create spectral polarization fringe amplitude and temporal instability predictions by applying the Berreman calculus and simple interferometric calculations to optics in beams of varying F/ number. We then apply the formalism to superachromatic six-crystal retarders in converging beams under beam thermal loading in outdoor environmental conditions for two of the world's largest observatories: the 10-m Keck telescope and the Daniel K. Inouye Solar Telescope (DKIST). DKIST will produce a 300-W optical beam, which has imposed stringent requirements on the large diameter six-crystal retarders, dichroic beamsplitters, and internal optics. DKIST retarders are used in a converging beam with F/ ratios between 8 and 62. The fringe spectral periods, amplitudes, and thermal models of retarder behavior assisted DKIST optical designs and calibration plans with future application to many astronomical spectropolarimeters. The Low Resolution Imaging Spectrograph with polarimetry instrument at Keck also uses six-crystal retarders in a converging F / 13 beam in a Cassegrain focus exposed to summit environmental conditions providing observational verification of our predictions.

Fusion of a polarized projectile with a polarized target

International Nuclear Information System (INIS)

Christley, J.A.; Johnson, R.C.; Thompson, I.J.

1995-01-01

The fusion cross sections for a polarized target with both unpolarized and polarized projectiles are studied. Expressions for the observables are given for the case when both nuclei are polarized. Calculations for fusion of an aligned 165 Ho target with 16 O and polarized 7 Li beams are presented

Secondary mirror system for the European Solar Telescope (EST)

Science.gov (United States)

Cavaller, L.; Siegel, B.; Prieto, G.; Hernandez, E.; Casalta, J. M.; Mercader, J.; Barriga, J.

2010-07-01

The European Solar Telescope (EST) is a European collaborative project to build a 4m class solar telescope in the Canary Islands, which is now in its design study phase. The telescope will provide diffraction limited performance for several instruments observing simultaneously at the Coudé focus at different wavelengths. A multi-conjugated adaptive optics system composed of a tip-tilt mirror and several deformable mirrors will be integrated in the telescope optical path. The secondary mirror system is composed of the mirror itself (Ø800mm), the alignment drives and the cooling system needed to remove the solar heat load from the mirror. During the design study the feasibility to provide fast tip-tilt capabilities at the secondary mirror to work as the adaptive optics tip-tilt mirror is also being evaluated.

The ARC (Astrophysical Research Consortium) telescope project.

Science.gov (United States)

Anderson, K. S.

A consortium of universities intends to construct a 3.5 meter optical-infrared telescope at a site in south-central New Mexico. The use of innovative mirror technology, a fast primary, and an alt-azimuth mounting results in a compact and lightweight instrument. This telescope will be uniquely well-suited for addressing certain observational programs by virtue of its capability for fully remote operation and rapid instrument changes.

A Galaxy Zoo - WorldWide Telescope Mashup: Expanding User Defined Exploration

Science.gov (United States)

Luebbert, Jarod; Sands, M.; Fay, J.; Smith, A.; Gay, P. L.; Galaxy Zoo Team

2010-01-01

We present a new way of exploring your favorite Galaxy Zoo galaxies within the context of the sky using Microsoft Research's WorldWide Telescope. Galaxy Zoo has a fantastic community that is eager to learn and contribute to science through morphological classifications of galaxies. WorldWide Telescope is an interactive observatory that allows users to explore the sky. WorldWide Telescope uses images from the world's best telescopes, including the galaxies of the Sloan Digital Sky Survey. WorldWide Telescope provides a fantastic sense of size and distance that is hard to experience in Galaxy Zoo. Creating tours from favorite galaxies directly from Galaxy Zoo aims to solve this dilemma.The incorporation of Galaxy Zoo and WorldWide telescope provides a great resource for users to learn more about the galaxies they are classifying. Users can now explore the areas around certain galaxies and view information about that location from within WorldWide Telescope. Not only does this encourage self-motivated research but after tours are created they can be shared with anyone. We hope this will help spread citizen science to different audiences via email, Facebook, and Twitter.Without the WorldWide Telescope team at Microsoft Research this project would not have been possible. Please go start exploring at http://wwt.galaxyzoo.org. This project was funded through the Microsoft Research Academic Program.

Memory and time: Backward and forward telescoping in Alzheimer's disease.

Science.gov (United States)

El Haj, Mohamad; Janssen, Steve M J; Antoine, Pascal

2017-10-01

Backward and forward telescoping are opposite timing biases. The former refers to misattributing events to earlier dates, whereas the latter refers to misattributing events to later dates. The present study investigated both biases in participants with Alzheimer's Disease (AD) and healthy older adults, matched on age, sex, and education level. Participants were asked to recall the years when five remote and five recent public events had occurred. They were also assessed with a cognitive and clinical battery that included a context memory task on which they had to associate letters and locations. Results showed backward telescoping for recent events and forward telescoping for remote events in AD participants and older adults. Furthermore, poorer context recall was observed in AD participants and older adults displaying backward telescoping than in those displaying forward telescoping. These findings suggest an association between the amount of contextual information recalled and the direction of the timing bias. Backward telescoping can be associated with deficiencies in retrieving context characteristics of events, which have been associated with retrograde amnesia and pathological changes to the hippocampus in AD. Copyright © 2017 Elsevier Inc. All rights reserved.

GPU-based online track reconstruction for the MuPix-telescope

Energy Technology Data Exchange (ETDEWEB)

Grzesik, Carsten [JGU, Mainz (Germany); Collaboration: Mu3e-Collaboration

2016-07-01

The MuPix telescope is a beam telescope consisting of High Voltage Monolithic Active Pixel Sensors (HV-MAPS). This type of sensor is going to be used for the Mu3e experiment, which is aiming to measure the lepton flavor violating decay μ→ eee with an ultimate sensitivity of 10{sup -16}. This sensitivity requires a high muon decay rate in the order of 1 GHz leading to a data rate of about 1 TBit/s for the whole detector. This needs to be reduced by a factor 1000 using online event selection algorithms on Graphical Processing Units (GPUs) before passing the data to the storage. A test setup for the MuPix sensors and parts of the Mu3e tracking detector readout is realized in a four plane telescope. The telescope can also be used to show the usability of an online track reconstruction using GPUs. As a result the telescope can provide online information about efficiencies of a device under test or the alignment of the telescope itself. This talk discusses the implementation of the GPU based track reconstruction and shows some results from recent testbeam campaigns.

Advanced Athermal Telescopes, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This proposed innovative athermal telescope design uses advanced lightweight and high-stiffness material of Beryllium-Aluminum (Be-38Al). Peregrine's expertise with...

ESO Telescope Designer Raymond Wilson Wins Prestigious Kavli Award for Astrophysics

Science.gov (United States)

2010-06-01

Raymond Wilson, whose pioneering optics research at ESO made today's giant telescopes possible thanks to "active optics" technology, has been awarded the 2010 Kavli Prize in astrophysics. The founder and original leader of the Optics and Telescopes Group at ESO, Wilson shares the million-dollar prize with two American scientists, Jerry Nelson and Roger Angel. The biennial prize, presented by the Norwegian Academy of Science and Letters, the Kavli Foundation, and the Norwegian Ministry of Education and Research, was instituted in 2008 and is given to researchers who significantly advance knowledge in the fields of nanoscience, neuroscience, and astrophysics, acting as a complement to the Nobel Prize. The award is named for and funded by Fred Kavli, the Norwegian entrepreneur and phi­lanthropist who later founded the Kavlico Corpora­tion in the US - today one of the world's largest suppliers of sensors for aeronautic, automotive and industrial applications. Wilson, who joined ESO in 1972, strived to achieve optical perfection, developing the concept of active optics as a way to enhance the size of telescopic primary mirrors. It is the size of these mirrors that determines the ability of a telescope to gather light and study faint and distant objects. Before active optics, mirrors over six metres in diameter were impossible, being too heavy, costly, and likely to bend from gravity and temperature changes. The use of active optics, which preserves optimal image quality by continually adjusting the mirror's shape during observations, made lighter, thinner so-called "meniscus mirrors" possible. Wilson first led the implementation of active optics in the revolutionary New Technology Telescope at ESO's La Silla Observatory, and continued to develop and improve the technology until his retirement in 1993. Since then, active optics have become a standard part of modern astronomy, applied in every big telescope including ESO's Very Large Telescope (VLT), a telescope array

Influence of aerosols, clouds, and sunglint on polarization spectra of Earthshine

Science.gov (United States)

Emde, Claudia; Buras-Schnell, Robert; Sterzik, Michael; Bagnulo, Stefano

2017-08-01

Context. Ground-based observations of the Earthshine, I.e., the light scattered by Earth to the Moon, and then reflected back to Earth, simulate space observations of our planet and represent a powerful benchmark for the studies of Earth-like planets. Earthshine spectra are strongly linearly polarized, owing to scattering by molecules and small particles in the atmosphere of the Earth and surface reflection, and may allow us to measure global atmospheric and surface properties of planet Earth. Aims: We aim to interpret already published spectropolarimetric observations of the Earthshine by comparing them with new radiative transfer model simulations including a fully realistic three-dimensional (3D) surface-atmosphere model for planet Earth. Methods: We used the highly advanced Monte Carlo radiative transfer model MYSTIC to simulate polarized radiative transfer in the atmosphere of the Earth without approximations regarding the geometry, taking into account the polarization from surface reflection and multiple scattering by molecules, aerosol particles, cloud droplets, and ice crystals. Results: We have shown that Earth spectropolarimetry is highly sensitive to all these input parameters, and we have presented simulations of a fully realistic Earth atmosphere-surface model including 3D cloud fields and two-dimensional (2D) surface property maps. Our modeling results show that scattering in high ice water clouds and reflection from the ocean surface are crucial to explain the continuum polarization at longer wavelengths as has been reported in Earthshine observations taken at the Very Large Telescope in 2011 (3.8% and 6.6% at 800 nm, depending on which part of Earth was visible from the Moon at the time of the observations). We found that the relatively high degree of polarization of 6.6% can be attributed to light reflected by the ocean surface in the sunglint region. High ice-water clouds reduce the amount of absorption in the O2A band and thus explain the weak O2

Photometry and Multipolar Magnetic Field Modeling of Polars: BY Camelopardalis and FL Ceti

Directory of Open Access Journals (Sweden)

P. A. Mason

2015-02-01

Full Text Available We present new broad band optical photometry of two magnetic cataclysmic variable stars, the asynchronous polar BY Camelopardalis and the short period polar FL Ceti. Observations were obtained at the 2.1-m Otto Struve Telescope of McDonald Observatory with 3s and 1s integration times respectively. In an attempt to understand the observed complex changes in accretion flow geometry observed in BY Cam, we performed full 3D MHD simulations assuming a variety of white dwarf magnetic field structures. We investigate fields with increasing complexity including both aligned and non-aligned dipole plus quadrupole field components. We compare model predictions with photometry at various phases of the beat cycle and find that synthetic light curves derived from a multipolar field structure are broadly consistent with optical photometry. FL Ceti is observed to have two very small accretion regions at the foot-points of the white dwarf’s magnetic field. Both accretion regions are visible at the same time in the high state and are about 100 degrees apart. MHD modeling using a dipole plus quadrupole field structure yields quite similar accretion regions as those observed in FL Ceti. We conclude that accretion flows calculated from MHD modeling of multi-polar magnetic fields produce synthetic light curves consistent with photometry of these magnetic cataclysmic variables.

Design and end-to-end modelling of a deployable telescope

Science.gov (United States)

Dolkens, Dennis; Kuiper, Hans

2017-09-01

Deployable optics have the potential of revolutionizing the field of high resolution Earth Observation. By offering the same resolutions as a conventional telescope, while using a much smaller launch volume and mass, the costs of high resolution image data can be brought down drastically. In addition, the technology will ultimately enable resolutions that are currently unattainable due to limitations imposed by the size of launcher fairings. To explore the possibilities and system complexities of a deployable telescope, a concept study was done to design a competitive deployable imager. A deployable telescope was designed for a ground sampling distance of 25 cm from an orbital altitude of 550 km. It offers an angular field of view of 0.6° and has a panchromatic channel as well as four multispectral bands in the visible and near infrared spectrum. The optical design of the telescope is based on an off-axis Korsch Three Mirror Anastigmat. A freeform tertiary mirror is used to ensure a diffraction limited image quality for all channels, while maintaining a compact design. The segmented primary mirror consists of four tapered aperture segments, which can be folded down during launch, while the secondary mirror is mounted on a deployable boom. In its stowed configuration, the telescope fits within a quarter of the volume of a conventional telescope reaching the same resolution. To reach a diffraction limited performance while operating in orbit, the relative position of each individual mirror segment must be controlled to a fraction of a wavelength. Reaching such tolerances with deployable telescope challenging, due to inherent uncertainties in the deployment mechanisms. Adding to the complexity is the fact that the telescope will be operating in a Low Earth Orbit (LEO) where it will be exposed to very dynamic thermal conditions. Therefore, the telescope will be equipped with a robust calibration system. Actuators underneath the primary mirror will be controlled using

Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2)

Science.gov (United States)

Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

2017-07-01

The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs) and Earth system models (ESMs) to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx), HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect caused by the

Selling the Space Telescope - The interpenetration of science, technology, and politics

Science.gov (United States)

Smith, Robert W.

1991-01-01

Attention is given to the politics of initiating the Space Telescope program and to the manner in which the coalition, or working consensus, for the Telescope was assembled, in particular, the role played by astronomers. It is contended that what ensued was a case study in the influence of government patronage on a large-scale scientific and technological program. It is concluded that while a politically feasible Space Telescope did result, in the selling process the Telescope had been both oversold and underfunded.

TADPOL: A 1.3 mm SURVEY OF DUST POLARIZATION IN STAR-FORMING CORES AND REGIONS

International Nuclear Information System (INIS)

Hull, Charles L. H.; Plambeck, Richard L.; Bower, Geoffrey C.; Heiles, Carl; Kwon, Woojin; Carpenter, John M.; Lamb, James W.; Pillai, Thushara; Crutcher, Richard M.; Hakobian, Nicholas S.; Looney, Leslie W.; Fiege, Jason D.; Franzmann, Erica; Houde, Martin; Hughes, A. Meredith; Marrone, Daniel P.; Matthews, Brenda C.; Pound, Marc W.; Rahman, Nurur; Sandell, Göran

2014-01-01

We present λ 1.3 mm Combined Array for Research in Millimeter-wave Astronomy observations of dust polarization toward 30 star-forming cores and eight star-forming regions from the TADPOL survey. We show maps of all sources, and compare the ∼2.''5 resolution TADPOL maps with ∼20'' resolution polarization maps from single-dish submillimeter telescopes. Here we do not attempt to interpret the detailed B-field morphology of each object. Rather, we use average B-field orientations to derive conclusions in a statistical sense from the ensemble of sources, bearing in mind that these average orientations can be quite uncertain. We discuss three main findings. (1) A subset of the sources have consistent magnetic field (B-field) orientations between large (∼20'') and small (∼2.''5) scales. Those same sources also tend to have higher fractional polarizations than the sources with inconsistent large-to-small-scale fields. We interpret this to mean that in at least some cases B-fields play a role in regulating the infall of material all the way down to the ∼1000 AU scales of protostellar envelopes. (2) Outflows appear to be randomly aligned with B-fields; although, in sources with low polarization fractions there is a hint that outflows are preferentially perpendicular to small-scale B-fields, which suggests that in these sources the fields have been wrapped up by envelope rotation. (3) Finally, even at ∼2.''5 resolution we see the so-called polarization hole effect, where the fractional polarization drops significantly near the total intensity peak. All data are publicly available in the electronic edition of this article

The ultraviolet telescope on the Astron satellite

International Nuclear Information System (INIS)

Boyarchuk, A.A.

1987-01-01

On 23 March 1983 in the USSR, the Astron astrophysical satellite, with the largest ultraviolet telescope (the UVT) in the world (main mirror diameter 80 cm) and a set of X-ray instruments on board was placed in a high-apogee orbit. The design of the ultraviolet telescope and the results of some of the observations carried out with it are described here. The X-ray instruments are discussed in a separate article. The ultraviolet telescope on the Astron astrophysical satellite is a result of the joint efforts of scientists and engineers at the Crimean Astrophysical Observatory (Academy of Sciences of the USSR), the Byurakan Astrophysical Observatory (Academy of Sciences of the Armenian USSR), and several industrial enterprises in our country. The Laboratoire d'Astronomie Spatiale (CNRS, Marseille, France) played a large role in building the spectrometer for the UVT

The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

Energy Technology Data Exchange (ETDEWEB)

Atwood, W.B.; /UC, Santa Cruz; Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Anderson, B. /UC, Santa Cruz; Axelsson, M.; /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Band, D.L.; /NASA, Goddard /NASA, Goddard; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bartelt, J.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bastieri, Denis; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bederede, D.; /DAPNIA, Saclay; Bellardi, F.; /INFN, Pisa; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bignami, G.F.; /Pavia U.; Bisello, D.; /INFN, Padua /Padua U.; Bissaldi, E.; /Garching, Max Planck Inst., MPE; Blandford, R.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Pisa /INFN, Pisa /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /INFN, Padua /Padua U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Kalmar U. /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /ASI, Rome /INFN, Pisa /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /DAPNIA, Saclay /NASA, Goddard /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; /more authors..

2009-05-15

The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy {gamma}-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy {gamma}-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3

Assembly and Integration Process of the First High Density Detector Array for the Atacama Cosmology Telescope

Science.gov (United States)

Li, Yaqiong; Choi, Steve; Ho, Shuay-Pwu; Crowley, Kevin T.; Salatino, Maria; Simon, Sara M.; Staggs, Suzanne T.; Nati, Federico; Wollack, Edward J.

2016-01-01

The Advanced ACTPol (AdvACT) upgrade on the Atacama Cosmology Telescope (ACT) consists of multichroicTransition Edge Sensor (TES) detector arrays to measure the Cosmic Microwave Background (CMB) polarization anisotropies in multiple frequency bands. The first AdvACT detector array, sensitive to both 150 and 230 GHz, is fabricated on a 150 mm diameter wafer and read out with a completely different scheme compared to ACTPol. Approximately 2000 TES bolometers are packed into the wafer leading to both a much denser detector density and readout circuitry. The demonstration of the assembly and integration of the AdvACT arrays is important for the next generation CMB experiments, which will continue to increase the pixel number and density. We present the detailed assembly process of the first AdvACT detector array.

UV/Visible Telescope with Hubble Disposal

Science.gov (United States)

Benford, Dominic J.

2013-01-01

Submission Overview: Our primary objective is to convey a sense of the significant advances possible in astrophysics investigations for major Cosmic Origins COR program goals with a 2.4m telescope asset outfitted with one or more advanced UV visible instruments. Several compelling science objectives were identified based on community meetings these science objectives drove the conceptual design of instruments studied by the COR Program Office during July September 2012. This RFI submission encapsulates the results of that study, and suggests that a more detailed look into the instrument suite should be conducted to prove viability and affordability to support the demonstrated scientific value. This study was conducted in the context of a larger effort to consider the options available for a mission to dispose safely of Hubble hence, the overall architecture considered for the mission we studied for the 2.4m telescope asset included resource sharing. This mitigates combined cost and risk and provides naturally for a continued US leadership role in astrophysics with an advanced, general-purpose UV visible space telescope.

ROTATIONAL VARIABILITY OF EARTH'S POLAR REGIONS: IMPLICATIONS FOR DETECTING SNOWBALL PLANETS

International Nuclear Information System (INIS)

Cowan, Nicolas B.; Robinson, Tyler; Agol, Eric; Meadows, Victoria S.; Shields, Aomawa L.; Livengood, Timothy A.; Deming, Drake; A'Hearn, Michael F.; Wellnitz, Dennis D.; Charbonneau, David; Lisse, Carey M.; Seager, Sara

2011-01-01

We have obtained the first time-resolved, disk-integrated observations of Earth's poles with the Deep Impact spacecraft as part of the EPOXI mission of opportunity. These data mimic what we will see when we point next-generation space telescopes at nearby exoplanets. We use principal component analysis (PCA) and rotational light curve inversion to characterize color inhomogeneities and map their spatial distribution from these unusual vantage points, as a complement to the equatorial views presented by Cowan et al. in 2009. We also perform the same PCA on a suite of simulated rotational multi-band light curves from NASA's Virtual Planetary Laboratory three-dimensional spectral Earth model. This numerical experiment allows us to understand what sorts of surface features PCA can robustly identify. We find that the EPOXI polar observations have similar broadband colors as the equatorial Earth, but with 20%-30% greater apparent albedo. This is because the polar observations are most sensitive to mid-latitudes, which tend to be more cloudy than the equatorial latitudes emphasized by the original EPOXI Earth observations. The cloudiness of the mid-latitudes also manifests itself in the form of increased variability at short wavelengths in the polar observations and as a dominant gray eigencolor in the south polar observation. We construct a simple reflectance model for a snowball Earth. By construction, our model has a higher Bond albedo than the modern Earth; its surface albedo is so high that Rayleigh scattering does not noticeably affect its spectrum. The rotational color variations occur at short wavelengths due to the large contrast between glacier ice and bare land in those wavebands. Thus, we find that both the broadband colors and diurnal color variations of such a planet would be easily distinguishable from the modern-day Earth, regardless of viewing angle.

Scientific Performance of a Nano-satellite MeV Telescope

Energy Technology Data Exchange (ETDEWEB)

Lucchetta, Giulio; Berlato, Francesco; Rando, Riccardo; Bastieri, Denis; Urso, Giorgio, E-mail: giulio.lucchetta@desy.de, E-mail: fberlato@mpe.mpg.de [Dipartimento di Fisica and Astronomia “G. Galilei,” Università di Padova, I-35131 Padova (Italy)

2017-05-01

Over the past two decades, both X-ray and gamma-ray astronomy have experienced great progress. However, the region of the electromagnetic spectrum around ∼1 MeV is not so thoroughly explored. Future medium-sized gamma-ray telescopes will fill this gap in observations. As the timescale for the development and launch of a medium-class mission is ∼10 years, with substantial costs, we propose a different approach for the immediate future. In this paper, we evaluate the viability of a much smaller and cheaper detector: a nano-satellite Compton telescope, based on the CubeSat architecture. The scientific performance of this telescope would be well below that of the instrument expected for the future larger missions; however, via simulations, we estimate that such a compact telescope will achieve a performance similar to that of COMPTEL.

NECTAR: New electronics for the Cherenkov Telescope Array

Science.gov (United States)

Naumann, Christopher Lindsay; Bolmont, J.; Corona, P.; Delagnes, E.; Dzahini, D.; Feinstein, F.; Gascon, D.; Glicenstein, J.-F.; Nayman, P.; Rarbi, F.; Ribo, M.; Sanuy, A.; Siero, X.; Tavernet, J.-P.; Toussenel, F.; Vincent, P.; Vorobiov, S.

2012-12-01

The international CTA consortium is currently in the preparatory phase for the development of the next-generation Cherenkov Telescope Array (CTA [1]), based on the return of experience from the three major current-generation arrays H.E.S.S., MAGIC and VERITAS. To achieve an unprecedented sensitivity and energy range for TeV gamma rays, a new kind of flexible and powerful yet inexpensive front-end hardware will be required for the order of 105 channels of photodetectors in up to 100 telescopes. One possible solution is the NECTAr (New Electronics for the Cherenkov Telescope Array) system, based on the integration of as much as possible of the front-end electronics (amplifiers, fast analogue samplers, memory and ADCs) into a single ASIC for very fast readout performance and a significant reduction of the cost and the lower consumption per channel, while offering a high degree of flexibility both for the triggering and the readout of the telescope. The current status of its development is presented, along with newest results from measurements and simulation studies.

Neutron polarization

International Nuclear Information System (INIS)

Firk, F.W.K.

1976-01-01

Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

THE SOLAR NEIGHBORHOOD. XXVIII. THE MULTIPLICITY FRACTION OF NEARBY STARS FROM 5 TO 70 AU AND THE BROWN DWARF DESERT AROUND M DWARFS

International Nuclear Information System (INIS)

Dieterich, Sergio B.; Henry, Todd J.; Golimowski, David A.; Krist, John E.; Tanner, Angelle M.

2012-01-01

We report on our analysis of Hubble Space Telescope/NICMOS snapshot high-resolution images of 255 stars in 201 systems within ∼10 pc of the Sun. Photometry was obtained through filters F110W, F180M, F207M, and F222M using NICMOS Camera 2. These filters were selected to permit clear identification of cool brown dwarfs through methane contrast imaging. With a plate scale of 76 mas pixel –1 , NICMOS can easily resolve binaries with subarcsecond separations in the 19.''5×19.''5 field of view. We previously reported five companions to nearby M and L dwarfs from this search. No new companions were discovered during the second phase of data analysis presented here, confirming that stellar/substellar binaries are rare. We establish magnitude and separation limits for which companions can be ruled out for each star in the sample, and then perform a comprehensive sensitivity and completeness analysis for the subsample of 138 M dwarfs in 126 systems. We calculate a multiplicity fraction of 0.0 +3.5 –0.0 % for L companions to M dwarfs in the separation range of 5-70 AU, and 2.3 +5.0 –0.7 % for L and T companions to M dwarfs in the separation range of 10-70 AU. We also discuss trends in the color-magnitude diagrams using various color combinations and present astrometry for 19 multiple systems in our sample. Considering these results and results from several other studies, we argue that the so-called brown dwarf desert extends to binary systems with low-mass primaries and is largely independent of primary mass, mass ratio, and separations. While focusing on companion properties, we discuss how the qualitative agreement between observed companion mass functions and initial mass functions suggests that the paucity of brown dwarfs in either population may be due to a common cause and not due to binary formation mechanisms.

THE SOLAR NEIGHBORHOOD. XXVIII. THE MULTIPLICITY FRACTION OF NEARBY STARS FROM 5 TO 70 AU AND THE BROWN DWARF DESERT AROUND M DWARFS

Energy Technology Data Exchange (ETDEWEB)

Dieterich, Sergio B.; Henry, Todd J. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302-4106 (United States); Golimowski, David A. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Krist, John E. [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Tanner, Angelle M., E-mail: dieterich@chara.gsu.edu [Department of Physics and Astronomy, Mississippi State University, Starkville, MS 39762 (United States)

2012-08-15

We report on our analysis of Hubble Space Telescope/NICMOS snapshot high-resolution images of 255 stars in 201 systems within {approx}10 pc of the Sun. Photometry was obtained through filters F110W, F180M, F207M, and F222M using NICMOS Camera 2. These filters were selected to permit clear identification of cool brown dwarfs through methane contrast imaging. With a plate scale of 76 mas pixel{sup -1}, NICMOS can easily resolve binaries with subarcsecond separations in the 19.''5 Multiplication-Sign 19.''5 field of view. We previously reported five companions to nearby M and L dwarfs from this search. No new companions were discovered during the second phase of data analysis presented here, confirming that stellar/substellar binaries are rare. We establish magnitude and separation limits for which companions can be ruled out for each star in the sample, and then perform a comprehensive sensitivity and completeness analysis for the subsample of 138 M dwarfs in 126 systems. We calculate a multiplicity fraction of 0.0{sup +3.5}{sub -0.0}% for L companions to M dwarfs in the separation range of 5-70 AU, and 2.3{sup +5.0}{sub -0.7}% for L and T companions to M dwarfs in the separation range of 10-70 AU. We also discuss trends in the color-magnitude diagrams using various color combinations and present astrometry for 19 multiple systems in our sample. Considering these results and results from several other studies, we argue that the so-called brown dwarf desert extends to binary systems with low-mass primaries and is largely independent of primary mass, mass ratio, and separations. While focusing on companion properties, we discuss how the qualitative agreement between observed companion mass functions and initial mass functions suggests that the paucity of brown dwarfs in either population may be due to a common cause and not due to binary formation mechanisms.

Lunar-based optical telescopes: Planning astronomical tools of the twenty-first century

Science.gov (United States)

Hilchey, J. D.; Nein, M. E.

1995-02-01

A succession of optical telescopes, ranging in aperture from 1 to 16 m or more, can be deployed and operated on the lunar surface over the next half-century. These candidates to succeed NASA's Great Observatories would capitalize on the unique observational advantages offered by the Moon. The Lunar Telescope Working Group and the LUTE Task Team of the George C. Marshall Space Flight Center (MSFC) have assessed the feasibility of developing and deploying these facilities. Studies include the 16-m Large Lunar Telescope (LLT); the Lunar Cluster Telescope Experiment (LCTE), a 4-m precursor to the LLT; the 2-m Lunar Transit Telescope (LTT); and its precursor, the 1-m Lunar Ultraviolet Telescope Experiment (LUTE). The feasibility of developing and deploying each telescope was assessed and system requirements and options for supporting technologies, subsystems, transportation, and operations were detailed. Influences of lunar environment factors and site selection on telescope design and operation were evaluated, and design approaches and key tradeoffs were established. This paper provides an overview of the study results. Design concepts and brief system descriptions are provided, including subsystem and mission options selected for the concepts.

An optics education program designed around experiments with small telescopes

Science.gov (United States)

Pompea, Stephen M.; Sparks, Robert T.; Walker, Constance E.; Dokter, Erin F. C.

2010-08-01

The National Optical Astronomy Observatory has led the development of a new telescope kit for kids as part of a strategic plan to interest young children in science. This telescope has been assembled by tens of thousands of children nationwide, who are now using this high-quality telescope to conduct optics experiments and to make astronomical observations. The Galileoscope telescope kit and its associated educational program are an outgrowth of the NSF sponsored "Hands-On Optics" (HOO) project, a collaboration of the SPIE, the Optical Society of America, and NOAO. This project developed optics kits and activities for upper elementary students and has reached over 20,000 middle school kids in afterschool programs. HOO is a highly flexible educational program and was featured as an exemplary informal science program by the National Science Teachers Association. Our new "Teaching with Telescopes" program builds on HOO, the Galileoscope and other successful optical education projects.

Three-photon polarization ququarts: polarization, entanglement and Schmidt decompositions

International Nuclear Information System (INIS)

Fedorov, M V; Miklin, N I

2015-01-01

We consider polarization states of three photons, propagating collinearly and having equal given frequencies but with arbitrary distributed horizontal or vertical polarizations of photons. A general form of such states is a superposition of four basic three-photon polarization modes, to be referred to as the three-photon polarization ququarts (TPPQ). All such states can be considered as consisting of one- and two-photon parts, which can be entangled with each other. The degrees of entanglement and polarization, as well as the Schmidt decomposition and Stokes vectors of TPPQ are found and discussed. (paper)

The Atacama Cosmology Telescope: Instrument

Science.gov (United States)

Thornton, Robert J.; Atacama Cosmology Telescope Team

2010-01-01

The 6-meter Atacama Cosmology Telescope (ACT) is making detailed maps of the Cosmic Microwave Background at Cerro Toco in northern Chile. In this talk, I focus on the design and operation of the telescope and its commissioning instrument, the Millimeter Bolometer Array Camera. The camera contains three independent sets of optics that operate at 148 GHz, 217 GHz, and 277 GHz with arcminute resolution, each of which couples to a 1024-element array of Transition Edge Sensor (TES) bolometers. I will report on the camera performance, including the beam patterns, optical efficiencies, and detector sensitivities. Under development for ACT is a new polarimeter based on feedhorn-coupled TES devices that have improved sensitivity and are planned to operate at 0.1 K.

The CCAT-prime Extreme Field-of-View Submillimeter Telescope on Cerro Chajnantor

Science.gov (United States)

Koopman, Brian; Bertoldi, Frank; Chapman, Scott; Fich, Michel; Giovanelli, Riccardo; Haynes, Martha P.; Herter, Terry L.; Murray, Norman W.; Niemack, Michael D.; Riechers, Dominik; Schilke, Peter; Stacey, Gordon J.; Stutzki, Juergen; CCAT-prime Collaboration

2017-01-01

CCAT-prime is a six meter aperture off-axis submillimeter telescope that we plan to build at 5600m elevation on Cerro Chajnantor in Chile. The CCAT-prime optics are based on a cross-Dragone design with high throughput and a wide field-of-view optimized to increase the mapping speed of next generation cosmic microwave background (CMB) observations. These characteristics make CCAT-prime an excellent platform for a wide range of next generation millimeter and submillimeter science goals, and a potential platform for CMB stage-IV measurements. Here we present the telescope design for CCAT-prime and review the science goals.Taking advantage of the high elevation site, the first generation instrument for CCAT-prime will measure seven different frequency bands from 350um to 3mm. These seven bands will enable precise measurements of the Sunyaev-Zel’dovich effects (SZE) by separating contributions from CMB, thermal SZE, kinetic SZE, bright submm galaxies, and radio sources with a goal of extracting the peculiar velocities from a large number of galaxy clusters. Additional science priorities for CCAT-prime include: Galactic Ecology studies of the dynamic intersteller medium by mapping the fine structure lines [CI], [CII] and [NII] as well as high-excitation CO lines at the shortest wavelength bands; high redshift intensity mapping of [CII] emission from star-forming galaxies that likely dominates cosmic reionization at z~5-9 to probe the Epoch of Reionization; and next generation CMB polarization measurements to constrain inflation and cosmological models. The CCAT-prime facility will further our understanding of astrophysical processes from moments after the Big Bang to the present-day evolution of the Milky Way.

Polarization splitter and polarization rotator designs based on transformation optics.

Science.gov (United States)

Kwon, Do-Hoon; Werner, Douglas H

2008-11-10

The transformation optics technique is employed in this paper to design two optical devices - a two-dimensional polarization splitter and a three-dimensional polarization rotator for propagating beams. The polarization splitter translates the TM- and the TE-polarized components of an incident beam in opposite directions (i.e., shifted up or shifted down). The polarization rotator rotates the polarization state of an incoming beam by an arbitrary angle. Both optical devices are reflectionless at the entry and exit interfaces. Design details and full-wave simulation results are provided.

5,120 Superconducting Bolometers for the PIPER Balloon-Borne CMB Polarization Experiment

Science.gov (United States)

Benford, Dominic J.; Chuss, David T.; Hilton, Gene C.; Irwin, Kent D.; Jethava, Nikhil S.; Jhabvala, Christine A.; Kogut, Alan J.; Miller, Timothy M.; Mirel, Paul; Moseley, S. Harvey;

High performance Lyot and PIAA coronagraphy for arbitrarily shaped telescope apertures

Energy Technology Data Exchange (ETDEWEB)

Guyon, Olivier; Hinz, Philip M. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Cady, Eric [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Belikov, Ruslan [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Martinache, Frantz, E-mail: guyon@naoj.org [National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States)

2014-01-10

Two high-performance coronagraphic approaches compatible with segmented and obstructed telescope pupils are described. Both concepts use entrance pupil amplitude apodization and a combined phase and amplitude focal plane mask to achieve full coronagraphic extinction of an on-axis point source. While the first concept, called Apodized Pupil Complex Mask Lyot Coronagraph (APCMLC), relies on a transmission mask to perform the pupil apodization, the second concept, called Phase-Induced Amplitude Apodization complex mask coronagraph (PIAACMC), uses beam remapping for lossless apodization. Both concepts theoretically offer complete coronagraphic extinction (infinite contrast) of a point source in monochromatic light, with high throughput and sub-λ/D inner working angle, regardless of aperture shape. The PIAACMC offers nearly 100% throughput and approaches the fundamental coronagraph performance limit imposed by first principles. The steps toward designing the coronagraphs for arbitrary apertures are described for monochromatic light. Designs for the APCMLC and the higher performance PIAACMC are shown for several monolith and segmented apertures, such as the apertures of the Subaru Telescope, Giant Magellan Telescope, Thirty Meter Telescope, the European Extremely Large Telescope, and the Large Binocular Telescope. Performance in broadband light is also quantified, suggesting that the monochromatic designs are suitable for use in up to 20% wide spectral bands for ground-based telescopes.

The Nuclear Spectroscopic Telescope Array (NuSTAR)

DEFF Research Database (Denmark)

Harrison, Fiona A.; Boggs, Steve; Christensen, Finn Erland

2010-01-01

The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing hard X-ray (6 - 80 keV) telescope to orbit. NuSTAR will offer a factor 50 - 100 sensitivity improvement compared to previous collimated or coded mask imagers that have operated...... in this energy band. In addition, NuSTAR provides sub-arcminute imaging with good spectral resolution over a 12-arcminute eld of view. After launch, NuSTAR will carry out a two-year primary science mission that focuses on four key programs: studying the evolution of massive black holes through surveys carried...... on-orbit deployment of an extendable mast. An aspect and alignment metrology system enable reconstruction of the absolute aspect and variations in the telescope alignment resulting from mast exure during ground data processing. Data will be publicly available at GSFC's High Energy Archive Research...

Physics and astrophysics with gamma-ray telescopes

Energy Technology Data Exchange (ETDEWEB)

Vandenbroucke, J. [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)

2012-08-15

In the past few years gamma-ray astronomy has entered a golden age. A modern suite of telescopes is now scanning the sky over both hemispheres and over six orders of magnitude in energy. At {approx}TeV energies, only a handful of sources were known a decade ago, but the current generation of ground-based imaging atmospheric Cherenkov telescopes (H.E.S.S., MAGIC, and VERITAS) has increased this number to nearly one hundred. With a large field of view and duty cycle, the Tibet and Milagro air shower detectors have demonstrated the promise of the direct particle detection technique for TeV gamma rays. At {approx}GeV energies, the Fermi Gamma-ray Space Telescope has increased the number of known sources by nearly an order of magnitude in its first year of operation. New classes of sources that were previously theorized to be gamma-ray emitters have now been confirmed observationally. Moreover, there have been surprise discoveries of GeV gamma-ray emission from source classes for which no theory predicted it was possible. In addition to elucidating the processes of high-energy astrophysics, gamma-ray telescopes are making essential contributions to fundamental physics topics including quantum gravity, gravitational waves, and dark matter. I summarize the current census of astrophysical gamma-ray sources, highlight some recent discoveries relevant to fundamental physics, and describe the synergetic connections between gamma-ray and neutrino astronomy. This is a brief overview intended in particular for particle physicists and neutrino astronomers, based on a presentation at the Neutrino 2010 conference in Athens, Greece. I focus in particular on results from Fermi (which was launched soon after Neutrino 2008), and conclude with a description of the next generation of instruments, namely HAWC and the Cherenkov Telescope Array.

Polarization dynamics and polarization time of random three-dimensional electromagnetic fields

International Nuclear Information System (INIS)

Voipio, Timo; Setaelae, Tero; Shevchenko, Andriy; Friberg, Ari T.

2010-01-01

We investigate the polarization dynamics of random, stationary three-dimensional (3D) electromagnetic fields. For analyzing the time evolution of the instantaneous polarization state, two intensity-normalized polarization autocorrelation functions are introduced, one based on a geometric approach with the Poincare vectors and the other on energy considerations with the Jones vectors. Both approaches lead to the same conclusions on the rate and strength of the polarization dynamics and enable the definition of a polarization time over which the state of polarization remains essentially unchanged. For fields obeying Gaussian statistics, the two correlation functions are shown to be expressible in terms of quantities characterizing partial 3D polarization and electromagnetic coherence. The 3D degree of polarization is found to have the same meaning in the 3D polarization dynamics as the usual two-dimensional (2D) degree of polarization does with planar fields. The formalism is demonstrated with several examples, and it is expected to be useful in applications dealing with polarization fluctuations of 3D light.

SEARCH FOR A MAGNETIC FIELD VIA CIRCULAR POLARIZATION IN THE WOLF-RAYET STAR EZ CMa

International Nuclear Information System (INIS)

De la Chevrotière, A.; St-Louis, N.; Moffat, A. F. J.

2013-01-01

We report on the first deep, direct search for a magnetic field via the circular polarization of Zeeman splitting in a Wolf-Rayet (W-R) star. Using the highly efficient ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope, we observed at three different epochs one of the best W-R candidates in the sky expected to harbor a magnetic field, the bright, highly variable WN4 star EZ CMa = WR6 = HD 50896. We looked for the characteristic circular polarization (Stokes V) pattern in strong emission lines that would arise as a consequence of a global, rotating magnetic field with a split monopole configuration. We also obtained nearly simultaneous linear polarization spectra (Stokes Q and U), which are dominated by electron scattering, most likely from a flattened wind with large-scale corotating structures. As the star rotates with a period of 3.766 days, our view of the wind changes, which in turn affects the value of the linear polarization in lines versus continuum at the ∼0.2% level. Depending on the epoch of observation, our Stokes V data were affected by significant crosstalk from Stokes Q and U to V. We removed this spurious signal from the circular polarization data and experimented with various levels of spectral binning to increase the signal-to-noise ratio of our data. In the end, no magnetic field is unambiguously detected in EZ CMa. Assuming that the star is intrinsically magnetic and harbors a split monopole configuration, we find an upper limit of B ∼ 100 G for the intensity of its field in the line-forming regions of the stellar wind.

SEARCH FOR A MAGNETIC FIELD VIA CIRCULAR POLARIZATION IN THE WOLF-RAYET STAR EZ CMa

Energy Technology Data Exchange (ETDEWEB)

De la Chevrotiere, A.; St-Louis, N.; Moffat, A. F. J. [Departement de Physique, Universite de Montreal and Centre de Recherche en Astrophysique du Quebec (CRAQ), C. P. 6128, succ. centre-ville, Montreal (Quebec) H3C 3J7 (Canada); Collaboration: MiMeS Collaboration

2013-02-20

We report on the first deep, direct search for a magnetic field via the circular polarization of Zeeman splitting in a Wolf-Rayet (W-R) star. Using the highly efficient ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope, we observed at three different epochs one of the best W-R candidates in the sky expected to harbor a magnetic field, the bright, highly variable WN4 star EZ CMa = WR6 = HD 50896. We looked for the characteristic circular polarization (Stokes V) pattern in strong emission lines that would arise as a consequence of a global, rotating magnetic field with a split monopole configuration. We also obtained nearly simultaneous linear polarization spectra (Stokes Q and U), which are dominated by electron scattering, most likely from a flattened wind with large-scale corotating structures. As the star rotates with a period of 3.766 days, our view of the wind changes, which in turn affects the value of the linear polarization in lines versus continuum at the {approx}0.2% level. Depending on the epoch of observation, our Stokes V data were affected by significant crosstalk from Stokes Q and U to V. We removed this spurious signal from the circular polarization data and experimented with various levels of spectral binning to increase the signal-to-noise ratio of our data. In the end, no magnetic field is unambiguously detected in EZ CMa. Assuming that the star is intrinsically magnetic and harbors a split monopole configuration, we find an upper limit of B {approx} 100 G for the intensity of its field in the line-forming regions of the stellar wind.

The first GCT camera for the Cherenkov Telescope Array

CERN Document Server

De Franco, A.; Allan, D.; Armstrong, T.; Ashton, T.; Balzer, A.; Berge, D.; Bose, R.; Brown, A.M.; Buckley, J.; Chadwick, P.M.; Cooke, P.; Cotter, G.; Daniel, M.K.; Funk, S.; Greenshaw, T.; Hinton, J.; Kraus, M.; Lapington, J.; Molyneux, P.; Moore, P.; Nolan, S.; Okumura, A.; Ross, D.; Rulten, C.; Schmoll, J.; Schoorlemmer, H.; Stephan, M.; Sutcliffe, P.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Varner, G.; Watson, J.; Zink, A.

2015-01-01

The Gamma Cherenkov Telescope (GCT) is proposed to be part of the Small Size Telescope (SST) array of the Cherenkov Telescope Array (CTA). The GCT dual-mirror optical design allows the use of a compact camera of diameter roughly 0.4 m. The curved focal plane is equipped with 2048 pixels of ~0.2{\\deg} angular size, resulting in a field of view of ~9{\\deg}. The GCT camera is designed to record the flashes of Cherenkov light from electromagnetic cascades, which last only a few tens of nanoseconds. Modules based on custom ASICs provide the required fast electronics, facilitating sampling and digitisation as well as first level of triggering. The first GCT camera prototype is currently being commissioned in the UK. On-telescope tests are planned later this year. Here we give a detailed description of the camera prototype and present recent progress with testing and commissioning.

An EUDET/AIDA Pixel Beam Telescope for Detector Development

CERN Document Server

Rubinskiy, I

2015-01-01

Ahigh resolution(σ< 2 μm) beam telescope based on monolithic active pixel sensors (MAPS) was developed within the EUDET collaboration. EUDET was a coordinated detector R&D programme for the future International Linear Collider providing test beam infrastructure to detector R&D groups. The telescope consists of six sensor planes with a pixel pitch of either 18.4 μm or 10 μmand canbe operated insidea solenoidal magnetic fieldofupto1.2T.Ageneral purpose cooling, positioning, data acquisition (DAQ) and offine data analysis tools are available for the users. The excellent resolution, readout rate andDAQintegration capabilities made the telescopea primary beam tests tool also for several CERN based experiments. In this report the performance of the final telescope is presented. The plans for an even more flexible telescope with three differentpixel technologies(ATLASPixel, Mimosa,Timepix) withinthenew European detector infrastructure project AIDA are presented.

Neutrino Telescope

International Nuclear Information System (INIS)

Coelin Baldo, Milla

2009-01-01

The present volume contains the proceedings of the 13. International Workshop on 'Neutrino Telescope', 17. of the series 'Un altro modo di guardare il cielo', held in Venice at the 'Istituto Veneto di Scienze, Lettere ed Arti' from March 10 to March 13, 2009. This series started in Venice 21 years ago, in 1988, motivated by the growing interest in the exciting field of the neutrino physics and astrophysics, with the aim to bring together experimentalists and theorists and encourage discussion on the most recent results and to chart the direction of future researchers.

Telescopic Overdenture: A Case Report

Science.gov (United States)

Shruthi, C. S.; Poojya, R.; Ram, Swati; Anupama

2017-01-01

Patient: This report describes the case of a 68 year old female patient who presented with the chief complaint of difficulty in chewing and poor aesthetics due to missing teeth. The patient was interested in saving the remaining natural teeth and desired minimal tissue coverage from the prosthesis. After consideration of all the factors involved, it was deemed advisable to resort to a palate free maxillary telescopic complete denture and a mandibular removable partial denture. Discussion: Considering the age of the patient and the cost involved, implant supported prosthesis was ruled out as a treatment option for the patient. A telescopic denture was chosen as a favourable treatment option since it overcomes many of the problems posed by conventional complete dentures like progressive bone loss, lower stability and retention, loss of periodontal proprioception and low masticatory efficiency. It also provides minimal tissue coverage and better distribution of forces. Evaluation of occlusion, esthetics, phonetics and comfort after 24 hours, 1 week and 1 month of treatment showed that the patient was happy with the prosthesis and was able to speak and chew well. Conclusion: Telescopic overdentures have better retention and stability as compared to conventional complete dentures. They improve the chewing efficiency, patient comfort and also decrease the alveolar bone resorption. As such they are an excellent alternative to conventional complete denture treatment. PMID:28533736

Telescopic Overdenture: A Case Report.

Science.gov (United States)

Shruthi, C S; Poojya, R; Ram, Swati; Anupama

2017-03-01

This report describes the case of a 68 year old female patient who presented with the chief complaint of difficulty in chewing and poor aesthetics due to missing teeth. The patient was interested in saving the remaining natural teeth and desired minimal tissue coverage from the prosthesis. After consideration of all the factors involved, it was deemed advisable to resort to a palate free maxillary telescopic complete denture and a mandibular removable partial denture. Considering the age of the patient and the cost involved, implant supported prosthesis was ruled out as a treatment option for the patient. A telescopic denture was chosen as a favourable treatment option since it overcomes many of the problems posed by conventional complete dentures like progressive bone loss, lower stability and retention, loss of periodontal proprioception and low masticatory efficiency. It also provides minimal tissue coverage and better distribution of forces. Evaluation of occlusion, esthetics, phonetics and comfort after 24 hours, 1 week and 1 month of treatment showed that the patient was happy with the prosthesis and was able to speak and chew well. Telescopic overdentures have better retention and stability as compared to conventional complete dentures. They improve the chewing efficiency, patient comfort and also decrease the alveolar bone resorption. As such they are an excellent alternative to conventional complete denture treatment.

Polarized electron sources

Energy Technology Data Exchange (ETDEWEB)

Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

1994-12-01

The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

Polarized electron sources

International Nuclear Information System (INIS)

Prepost, R.

1994-01-01

The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented

A cost-performance model for ground-based optical communications receiving telescopes

Science.gov (United States)

Lesh, J. R.; Robinson, D. L.

1986-01-01

An analytical cost-performance model for a ground-based optical communications receiving telescope is presented. The model considers costs of existing telescopes as a function of diameter and field of view. This, coupled with communication performance as a function of receiver diameter and field of view, yields the appropriate telescope cost versus communication performance curve.

VLTI First Fringes with Two Auxiliary Telescopes at Paranal

Science.gov (United States)

2005-03-01

World's Largest Interferometer with Moving Optical Telescopes on Track Summary The Very Large Telescope Interferometer (VLTI) at Paranal Observatory has just seen another extension of its already impressive capabilities by combining interferometrically the light from two relocatable 1.8-m Auxiliary Telescopes. Following the installation of the first Auxiliary Telescope (AT) in January 2004 (see ESO PR 01/04), the second AT arrived at the VLT platform by the end of 2004. Shortly thereafter, during the night of February 2 to 3, 2005, the two high-tech telescopes teamed up and quickly succeeded in performing interferometric observations. This achievement heralds an era of new scientific discoveries. Both Auxiliary Telescopes will be offered from October 1, 2005 to the community of astronomers for routine observations, together with the MIDI instrument. By the end of 2006, Paranal will be home to four operational ATs that may be placed at 30 different positions and thus be combined in a very large number of ways ("baselines"). This will enable the VLTI to operate with enormous flexibility and, in particular, to obtain extremely detailed (sharp) images of celestial objects - ultimately with a resolution that corresponds to detecting an astronaut on the Moon. PR Photo 07a/05: Paranal Observing Platform with AT1 and AT2 PR Photo 07b/05: AT1 and AT2 with Open Domes PR Photo 07c/05: Evening at Paranal with AT1 and AT2 PR Photo 07d/05: AT1 and AT2 under the Southern Sky PR Photo 07e/05: First Fringes with AT1 and AT2 PR Video Clip 01/05: Two ATs at Paranal (Extract from ESO Newsreel 15) A Most Advanced Device ESO PR Video 01/05 ESO PR Video 01/05 Two Auxiliary Telescopes at Paranal [QuickTime: 160 x 120 pix - 37Mb - 4:30 min] [QuickTime: 320 x 240 pix - 64Mb - 4:30 min] ESO PR Photo 07a/05 ESO PR Photo 07a/05 [Preview - JPEG: 493 x400 pix - 44k] [Normal - JPEG: 985 x 800 pix - 727k] [HiRes - JPEG: 5000 x 4060 pix - 13.8M] Captions: ESO PR Video Clip 01/05 is an extract from

Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2

Directory of Open Access Journals (Sweden)

I. Wohltmann

2017-07-01

Full Text Available The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs and Earth system models (ESMs to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx, HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect

Update on Multi-Variable Parametric Cost Models for Ground and Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Henrichs, Todd; Luedtke, Alexander; West, Miranda

2012-01-01

Parametric cost models can be used by designers and project managers to perform relative cost comparisons between major architectural cost drivers and allow high-level design trades; enable cost-benefit analysis for technology development investment; and, provide a basis for estimating total project cost between related concepts. This paper reports on recent revisions and improvements to our ground telescope cost model and refinements of our understanding of space telescope cost models. One interesting observation is that while space telescopes are 50X to 100X more expensive than ground telescopes, their respective scaling relationships are similar. Another interesting speculation is that the role of technology development may be different between ground and space telescopes. For ground telescopes, the data indicates that technology development tends to reduce cost by approximately 50% every 20 years. But for space telescopes, there appears to be no such cost reduction because we do not tend to re-fly similar systems. Thus, instead of reducing cost, 20 years of technology development may be required to enable a doubling of space telescope capability. Other findings include: mass should not be used to estimate cost; spacecraft and science instrument costs account for approximately 50% of total mission cost; and, integration and testing accounts for only about 10% of total mission cost.

The SPIRIT Telescope Initiative: Six Years On (Abstract)

Science.gov (United States)

Luckas, P.

2017-12-01

(Abstract only) Now in its sixth year of operation, the SPIRIT initiative remains unique in Australia, as a robust web-enabled robotic telescope initiative funded for education and outreach. With multiple modes of operation catering for a variety of usage scenarios and a fully supported education program, SPIRIT provides free access to contemporary astronomical tools for students and educators in Western Australia and beyond. The technical solution itself provides an excellent model for low cost robotic telescope installations, and the education program has evolved over time to include a broad range of student experiences - from engagement activities to authentic science. This paper details the robotic telescope solution, student interface, and educational philosophy, summarizes achievements and lessons learned, and examines the possibilities for future enhancement including spectroscopy.

Asteroid Observations with NCSFCT’s AZT-8 Telescope

Directory of Open Access Journals (Sweden)

Kozhukhov, O.M.

2017-01-01

Full Text Available The asteroid observations of the small Solar System bodies were carried out with the AZT-8 telescope (D=0.7 m, f/4 of the National Center of Space Facilities Control and Testing (NCSFCT during 2010-2013. The telescope is located near Yevpatoria, the observatory code according IAU is B17. The observational program included perturbed main belt asteroids and NEO’s for the GAIA FUN-SSO Company. The MPC database contains more than 4500 asteroids positions and magnitudes obtained during this period at AZT-8 telescope. The article presents analysis of the positional accuracy of B17 observations obtained from the comparison with the JPL HORIZONS ephemeris, and data from AstDyS-2 and NEODyS-2 web services.

Eyes on the Skies 400 Years of Telescopic Discovery

CERN Document Server

Schilling, Govert

2011-01-01

Adopted as the official book of the International Year of Astronomy (IYA) 2009, this stunningly illustrated history of telescopic discovery spans the range from the first telescopes via the Hubble Space Telescope to next generation platforms, and how they have changed and continue to change our view of the universe, our place in it and where it all came from. Eyes on the Skies features numerous full-page photographs and is printed in high-quality color throughout. Also includes the official IYA DVD with 59 minutes of narrated text, expert comments and interviews, animations, computer simulatio

Modal vibration testing of the DVA-1 radio telescope

Science.gov (United States)

Byrnes, Peter W. G.; Lacy, Gordon

2016-07-01

The Dish Verification Antenna 1 (DVA-1) is a 15m aperture offset Gregorian radio telescope featuring a rim-supported single piece molded composite primary reflector on an altitude-azimuth pedestal mount. Vibration measurements of the DVA-1 telescope were conducted over three days in October 2014 by NSI Herzberg engineers. The purpose of these tests was to measure the first several natural frequencies of the DVA-1 telescope. This paper describes the experimental approach, in particular the step-release method, and summarizes some interesting results, including unexpectedly high damping of the first mode over a narrow range of zenith angles.

Search for magnetic monopoles with the neutrino telescope ANTARES

International Nuclear Information System (INIS)

Picot-Clemente, N.

2010-01-01

The ANTARES neutrino telescope is located at a 2500 meters depth, and is composed of an array of 900 photomultipliers installed for the detection of Cherenkov light emitted by neutrino-induced muons, after having interacted with matter, and in order to reconstruct their directions. However, besides of being capable of detecting high energy neutrinos, neutrino telescopes could measure the incoming flux of magnetic monopoles in the detector. In this work, were first presented the different methods used in order to calibrate the photomultipliers, which are the heart of a neutrino telescope. The possibility of detecting magnetic monopoles with ANTARES was then discussed, and a first analysis optimised for the search for high velocity magnetic monopoles showed the great sensitivity offered by the telescope. Finally, a track reconstruction algorithm was modified, and a new analysis this time sensitive over a wider range of velocities was performed. After the application of the last analysis on the data taken in 2008 with the ANTARES telescope, new upper limits on the upward going magnetic monopole flux, of masses lower than 10 14 GeV were obtained, and are the best experimental constraints on their flux for the velocity region β ∼ [0.65, 0.995]. (author)

Reception and dissemination of American amateur telescope making in Sweden

Science.gov (United States)

Karnfelt, Johan

2017-04-01

This paper discusses the appropriation of the American Amateur Telescope Making (ATM) movement in Sweden in the 1940s and 1950s. A key player was the Swedish Astronomical Society, which in 1943, and inspired by the American example, launched a campaign to raise interest in ATM and disseminate the necessary knowledge amongst potential amateur astronomers. The campaign was successful and in just a few years it quadrupled the number of amateurs with access to telescopes. Swedish amateurs kept on building telescopes through the 1950s, but the activities then stalled with the introduction of cheap mass-market telescopes. The appropriation of ATM in Sweden is an important example of how technical innovations have shaped the course of amateur astronomy.

Promoting Diversity Through Polar Interdisciplinary Coordinated Education (Polar ICE)

Science.gov (United States)

McDonnell, J. D.; Hotaling, L. A.; Garza, C.; Van Dyk, P. B.; Hunter-thomson, K. I.; Middendorf, J.; Daniel, A.; Matsumoto, G. I.; Schofield, O.

2017-12-01

Polar Interdisciplinary Coordinated Education (ICE) is an education and outreach program designed to provide public access to the Antarctic and Arctic regions through polar data and interactions with the scientists. The program provides multi-faceted science communication training for early career scientists that consist of a face-to face workshop and opportunities to apply these skills. The key components of the scientist training workshop include cultural competency training, deconstructing/decoding science for non-expert audiences, the art of telling science stories, and networking with members of the education and outreach community and reflecting on communication skills. Scientists partner with educators to provide professional development for K-12 educators and support for student research symposia. Polar ICE has initiated a Polar Literacy initiative that provides both a grounding in big ideas in polar science and science communication training designed to underscore the importance of the Polar Regions to the public while promoting interdisciplinary collaborations between scientists and educators. Our ultimate objective is to promote STEM identity through professional development of scientists and educators while developing career awareness of STEM pathways in Polar science.

Polarization-independent broadband meta-holograms via polarization-dependent nanoholes.

Science.gov (United States)

Zhang, Xiaohu; Li, Xiong; Jin, Jinjin; Pu, Mingbo; Ma, Xiaoliang; Luo, Jun; Guo, Yinghui; Wang, Changtao; Luo, Xiangang

2018-05-17

Composed of ultrathin metal or dielectric nanostructures, metasurfaces can manipulate the phase, amplitude and polarization of electromagnetic waves at a subwavelength scale, which is promising for flat optical devices. In general, metasurfaces composed of space-variant anisotropic units are sensitive to the incident polarization due to the inherent polarization dependent geometric phase. Here, we implement polarization-independent broadband metasurface holograms constructed by polarization-dependent anisotropic elliptical nanoholes by elaborate design of complex amplitude holograms. The fabricated meta-hologram exhibits a polarization insensitive feature with an acceptable image quality. We verify the feasibility of the design algorithm for three-dimensional (3D) meta-holograms with simulation and the feasibility for two-dimensional (2D) meta-holograms is experimentally demonstrated at a broadband wavelength range from 405 nm to 632.8 nm. The effective polarization-independent broadband complex wavefront control with anisotropic elliptical nanoholes proposed in this paper greatly promotes the practical applications of the metasurface in technologies associated with wavefront manipulation, such as flat lens, colorful holographic displays and optical storage.

The E-ELT project: the telescope main structure detailed design study

Science.gov (United States)

Marchiori, Gianpietro; Busatta, Andrea; Ghedin, Leonardo; De Lorenzi, Simone

2012-09-01

The European Extremely Large Telescope (E-ELT) is the biggest telescope in the world. Within the Detailed Design activities, ESO has awarded EIE GROUP (European Industrial Engineering) a contract for the Design of the Main Structure to the point where the concept of the telescope has been consolidated, from a construction point of view. All the Design activities have been developed in order to create an integrated system in terms of functionality and performance, while the engineering activities have been performed with the aim of obtaining a telescope that can be built, transported, integrated, with a reduced maintainability.

NASA Telescopes Help Identify Most Distant Galaxy Cluster

Science.gov (United States)

2011-01-01

WASHINGTON -- Astronomers have uncovered a burgeoning galactic metropolis, the most distant known in the early universe. This ancient collection of galaxies presumably grew into a modern galaxy cluster similar to the massive ones seen today. The developing cluster, named COSMOS-AzTEC3, was discovered and characterized by multi-wavelength telescopes, including NASA's Spitzer, Chandra and Hubble space telescopes, and the ground-based W.M. Keck Observatory and Japan's Subaru Telescope. "This exciting discovery showcases the exceptional science made possible through collaboration among NASA projects and our international partners," said Jon Morse, NASA's Astrophysics Division director at NASA Headquarters in Washington. Scientists refer to this growing lump of galaxies as a proto-cluster. COSMOS-AzTEC3 is the most distant massive proto-cluster known, and also one of the youngest, because it is being seen when the universe itself was young. The cluster is roughly 12.6 billion light-years away from Earth. Our universe is estimated to be 13.7 billion years old. Previously, more mature versions of these clusters had been spotted at 10 billion light-years away. The astronomers also found that this cluster is buzzing with extreme bursts of star formation and one enormous feeding black hole. "We think the starbursts and black holes are the seeds of the cluster," said Peter Capak of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "These seeds will eventually grow into a giant, central galaxy that will dominate the cluster -- a trait found in modern-day galaxy clusters." Capak is first author of a paper appearing in the Jan. 13 issue of the journal Nature. Most galaxies in our universe are bound together into clusters that dot the cosmic landscape like urban sprawls, usually centered around one old, monstrous galaxy containing a massive black hole. Astronomers thought that primitive versions of these clusters, still forming and clumping

Stray light characteristics of the diffractive telescope system

Science.gov (United States)

Liu, Dun; Wang, Lihua; Yang, Wei; Wu, Shibin; Fan, Bin; Wu, Fan

2018-02-01

Diffractive telescope technology is an innovation solution in construction of large light-weight space telescope. However, the nondesign orders of diffractive optical elements (DOEs) may affect the imaging performance as stray light. To study the stray light characteristics of a diffractive telescope, a prototype was developed and its stray light analysis model was established. The stray light characteristics including ghost, point source transmittance, and veiling glare index (VGI) were analyzed. During the star imaging test of the prototype, the ghost images appeared around the star image as the exposure time of the charge-coupled device improving, consistent with the simulation results. The test result of VGI was 67.11%, slightly higher than the calculated value 57.88%. The study shows that the same order diffraction of the diffractive primary lens and correcting DOE is the main factor that causes ghost images. The stray light sources outside the field of view can illuminate the image plane through nondesign orders diffraction of the primary lens and contributes to more than 90% of the stray light flux on the image plane. In summary, it is expected that these works will provide some guidance for optimizing the imaging performance of diffractive telescopes.

A Cosmic Ray Telescope For Educational Purposes

International Nuclear Information System (INIS)

Voulgaris, G.; Kazanas, S.; Chamilothoris, I.

2010-01-01

Cosmic ray detectors are widely used, for educational purposes, in order to motivate students to the physics of elementary particles and astrophysics. Using a 'telescope' of scintillation counters, the directional characteristics, diurnal variation, correlation with solar activity, can be determined, and conclusions about the composition, origin and interaction of elementary particles with the magnetic field of earth can be inferred. A telescope was built from two rectangular scintillator panels with dimensions: 91.6x1.9x3.7 cm 3 . The scintillators are placed on top of each other, separated by a fixed distance of 34.6 cm. They are supported by a wooden frame which can be rotated around a horizontal axis. Direction is determined by the coincidence of the signals of the two PMTs. Standard NIM modules are used for readout. This device is to be used in the undergraduate nuclear and particle physics laboratory. The design and construction of the telescope as well as some preliminary results are presented.

San Pedro Martir Telescope: Mexican design endeavor

Science.gov (United States)

Toledo-Ramirez, Gengis K.; Bringas-Rico, Vicente; Reyes, Noe; Uribe, Jorge; Lopez, Aldo; Tovar, Carlos; Caballero, Xochitl; Del-Llano, Luis; Martinez, Cesar; Macias, Eduardo; Lee, William; Carramiñana, Alberto; Richer, Michael; González, Jesús; Sanchez, Beatriz; Lucero, Diana; Manuel, Rogelio; Segura, Jose; Rubio, Saul; Gonzalez, German; Hernandez, Obed; García, Mary; Lazaro, Jose; Rosales-Ortega, Fabian; Herrera, Joel; Sierra, Gerardo; Serrano, Hazael

2016-08-01

The Telescopio San Pedro Martir (TSPM) is a new ground-based optical telescope project, with a 6.5 meters honeycomb primary mirror, to be built in the Observatorio Astronomico Nacional on the Sierra San Pedro Martir (OAN-SPM) located in Baja California, Mexico. The OAN-SPM has an altitude of 2830 meters above sea level; it is among the best location for astronomical observation in the world. It is located 1830 m higher than the atmospheric inversion layer with 70% of photometric nights, 80% of spectroscopic nights and a sky brightness up to 22 mag/arcsec2. The TSPM will be suitable for general science projects intended to improve the knowledge of the universe established on the Official Mexican Program for Science, Technology and Innovation 2014-2018. The telescope efforts are headed by two Mexican institutions in name of the Mexican astronomical community: the Universidad Nacional Autonoma de Mexico and the Instituto Nacional de Astrofisica, Optica y Electronica. The telescope has been financially supported mainly by the Consejo Nacional de Ciencia y Tecnologia (CONACYT). It is under development by Mexican scientists and engineers from the Center for Engineering and Industrial Development. This development is supported by a Mexican-American scientific cooperation, through a partnership with the University of Arizona (UA), and the Smithsonian Astrophysical Observatory (SAO). M3 Engineering and Technology Corporation in charge of enclosure and building design. The TSPM will be designed to allow flexibility and possible upgrades in order to maximize resources. Its optical and mechanical designs are based upon those of the Magellan and MMT telescopes. The TSPM primary mirror and its cell will be provided by the INAOE and UA. The telescope will be optimized from the near ultraviolet to the near infrared wavelength range (0.35-2.5 m), but will allow observations up to 26μm. The TSPM will initially offer a f/5 Cassegrain focal station. Later, four folded Cassegrain and

The Lovell Telescope and its role in pulsar astronomy

Science.gov (United States)

Lyne, Andrew; Morison, Ian

2017-12-01

This year marks the 60th anniversary of the commissioning of the 250-ft telescope at Jodrell Bank Observatory, and the 50th anniversary of the discovery of pulsars at Cambridge. Both events resulted in enduring astronomical researches that have become intimately entwined, and here we celebrate them with a brief historical account of their relationship. We describe how the completion of the telescope in October 1957 coincided with the launch of Sputnik 1 at the start of the space race, a timely circumstance that was the financial saviour of Bernard Lovell's ambitious project. The telescope established a vital role in space tracking and, by the time that pulsars were discovered a decade later, was supported by an infrastructure that allowed their prompt, successful observation. Technical innovations to both the telescope and its receivers since then have continued to make it a superb tool for world-leading pulsar investigations and the study of the radio Universe.

Radio telescope reflectors historical development of design and construction

CERN Document Server

Baars, Jacob W M

2018-01-01

This book demonstrates how progress in radio astronomy is intimately linked to the development of reflector antennas of increasing size and precision. The authors describe the design and construction of major radio telescopes as those in Dwingeloo, Jodrell Bank, Parkes, Effelsberg and Green Bank since 1950 up to the present as well as millimeter wavelength telescopes as the 30m MRT of IRAM in Spain, the 50m LMT in Mexico and the ALMA submillimeter instrument. The advances in methods of structural design and coping with environmental influences (wind, temperature, gravity) as well as application of new materials are explained in a non-mathematical, descriptive and graphical way along with the story of the telescopes. Emphasis is placed on the interplay between astronomical and electromagnetic requirements and structural, mechanical and control solutions. A chapter on management aspects of large telescope projects closes the book. The authors address a readership with interest in the progress of engineering sol...

FACT. Normalized and asynchronous mirror alignment for Cherenkov telescopes

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