Chinese SLE Treatment and Research group (CSTAR) registry: II. Prevalence and risk factors of pulmonary arterial hypertension in Chinese patients with systemic lupus erythematosus.

PubMed

Li, M; Wang, Q; Zhao, J; Li, Z; Ye, Z; Li, C; Li, X; Zhu, P; Wang, Z; Zheng, Y; Li, X; Zhang, M; Tian, Z; Liu, Y; He, J; Zhang, F; Zhao, Y; Zeng, X

2014-09-01

To estimate the prevalence of pulmonary arterial hypertension (PAH) and risk factors for PAH in patients registered in the Chinese SLE Treatment and Research group (CSTAR) database, the first online registry of Chinese patients with systemic lupus erythematosus (SLE). A prospective cross-sectional study of patients with SLE was conducted using the CSTAR registry. Resting transthoracic echocardiography was used to estimate pulmonary artery pressure (PAP); PAH was defined as systolic PAP (PASP)≥40 mmHg. Patients with interstitial lung disease, valvular disease or cardiomyopathy were excluded because of disease influence on PAP. We explored potential risk factors for PAH including patient characteristics, organ involvement, laboratory findings and SLE disease activity. Of 1934 patients with SLE, 74 had PASP with 54.2±17.1 (40,106) mmHg and were diagnosed with probable PAH. The incidences of lupus nephritis, pleuritis, pericarditis, hypocomplementemia, anti-SSA, and anti-ribonucleoprotein (RNP) were significantly higher in patients with PAH than in those without (p<0.05). SLE disease activity was significantly higher in patients with PAH than in unaffected patients (p<0.05). Multivariate analysis indicated that pericarditis (odds ratio (OR)=4.248), pleuritis (OR=3.061) and anti-RNP (OR=2.559) were independent risk factors for PAH in patients with SLE (p<0.05). The possible prevalence of PAH was 3.8% in Chinese patients with SLE in the CSTAR registry. The significant association of pericarditis, pleuritis and anti-RNP positivity with PAH suggests that higher disease activity and vasculopathy may both contribute to the development of PAH in SLE, which need be treated aggressively to improve prognosis. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Feasibility study of an optically coherent telescope array in space

NASA Technical Reports Server (NTRS)

Traub, W. A.

1983-01-01

Numerical methods of image construction which can be used to produce very high angular resolution images at optical wavelengths of astronomical objects from an orbiting array of telescopes are discussed and a concept is presented for a phase-coherent optical telescope array which may be deployed by space shuttle in the 1990's. The system would start as a four-element linear array with a 12 m baseline. The initial module is a minimum redundant array with a photon-counting collecting area three times larger than space telescope and a one dimensional resolution of better than 0.01 arc seconds in the visible range. Later additions to the array would build up facility capability. The advantages of a VLBI observatory in space are considered as well as apertures for the telescopes.

High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center

DOEpatents

Norbert, M.A.; Yale, O.

1992-04-28

A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes. 15 figs.

High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center

DOEpatents

Norbert, Massie A.; Yale, Oster

1992-01-01

A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

High resolution telescope

DOEpatents

Massie, Norbert A.; Oster, Yale

1992-01-01

A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activites. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

Monte Carlo studies of medium-size telescope designs for the Cherenkov Telescope Array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, M. D.; Jogler, T.; Dumm, J.

In this paper, we present studies for optimizing the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Results focus on mid-sized telescopes (MSTs) for CTA, detecting very high energy gamma rays in the energy range from a few hundred GeV to a few tens of TeV. We describe a novel, flexible detector Monte Carlo package, FAST (FAst Simulation for imaging air cherenkov Telescopes), that we use to simulate different array and telescope designs. The simulation is somewhat simplified to allow for efficient exploration over a large telescope design parameter space. We investigate a wide range of telescope performance parametersmore » including optical resolution, camera pixel size, and light collection area. In order to ensure a comparison of the arrays at their maximum sensitivity, we analyze the simulations with the most sensitive techniques used in the field, such as maximum likelihood template reconstruction and boosted decision trees for background rejection. Choosing telescope design parameters representative of the proposed Davies–Cotton (DC) and Schwarzchild–Couder (SC) MST designs, we compare the performance of the arrays by examining the gamma-ray angular resolution and differential point-source sensitivity. We further investigate the array performance under a wide range of conditions, determining the impact of the number of telescopes, telescope separation, night sky background, and geomagnetic field. We find a 30–40% improvement in the gamma-ray angular resolution at all energies when comparing arrays with an equal number of SC and DC telescopes, significantly enhancing point-source sensitivity in the MST energy range. Finally, we attribute the increase in point-source sensitivity to the improved optical point-spread function and smaller pixel size of the SC telescope design.« less

Monte Carlo studies of medium-size telescope designs for the Cherenkov Telescope Array

DOE PAGES

Wood, M. D.; Jogler, T.; Dumm, J.; ...

2015-06-07

In this paper, we present studies for optimizing the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Results focus on mid-sized telescopes (MSTs) for CTA, detecting very high energy gamma rays in the energy range from a few hundred GeV to a few tens of TeV. We describe a novel, flexible detector Monte Carlo package, FAST (FAst Simulation for imaging air cherenkov Telescopes), that we use to simulate different array and telescope designs. The simulation is somewhat simplified to allow for efficient exploration over a large telescope design parameter space. We investigate a wide range of telescope performance parametersmore » including optical resolution, camera pixel size, and light collection area. In order to ensure a comparison of the arrays at their maximum sensitivity, we analyze the simulations with the most sensitive techniques used in the field, such as maximum likelihood template reconstruction and boosted decision trees for background rejection. Choosing telescope design parameters representative of the proposed Davies–Cotton (DC) and Schwarzchild–Couder (SC) MST designs, we compare the performance of the arrays by examining the gamma-ray angular resolution and differential point-source sensitivity. We further investigate the array performance under a wide range of conditions, determining the impact of the number of telescopes, telescope separation, night sky background, and geomagnetic field. We find a 30–40% improvement in the gamma-ray angular resolution at all energies when comparing arrays with an equal number of SC and DC telescopes, significantly enhancing point-source sensitivity in the MST energy range. Finally, we attribute the increase in point-source sensitivity to the improved optical point-spread function and smaller pixel size of the SC telescope design.« less

Optical aperture synthesis with electronically connected telescopes

PubMed Central

Dravins, Dainis; Lagadec, Tiphaine; Nuñez, Paul D.

2015-01-01

Highest resolution imaging in astronomy is achieved by interferometry, connecting telescopes over increasingly longer distances and at successively shorter wavelengths. Here, we present the first diffraction-limited images in visual light, produced by an array of independent optical telescopes, connected electronically only, with no optical links between them. With an array of small telescopes, second-order optical coherence of the sources is measured through intensity interferometry over 180 baselines between pairs of telescopes, and two-dimensional images reconstructed. The technique aims at diffraction-limited optical aperture synthesis over kilometre-long baselines to reach resolutions showing details on stellar surfaces and perhaps even the silhouettes of transiting exoplanets. Intensity interferometry circumvents problems of atmospheric turbulence that constrain ordinary interferometry. Since the electronic signal can be copied, many baselines can be built up between dispersed telescopes, and over long distances. Using arrays of air Cherenkov telescopes, this should enable the optical equivalent of interferometric arrays currently operating at radio wavelengths. PMID:25880705

MEMS Microshutter Arrays for James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Li, Mary J.; Beamesderfer, Michael; Babu, Sachi; Bajikar, Sateesh; Ewin, Audrey; Franz, Dave; Hess, Larry; Hu, Ron; Jhabvala, Murzy; Kelly, Dan;

PHOTOMETRY OF VARIABLE STARS FROM DOME A, ANTARCTICA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Lingzhi; Macri, Lucas M.; Krisciunas, Kevin

Dome A on the Antarctic plateau is likely one of the best observing sites on Earth thanks to the excellent atmospheric conditions present at the site during the long polar winter night. We present high-cadence time-series aperture photometry of 10,000 stars with i < 14.5 mag located in a 23 deg{sup 2} region centered on the south celestial pole. The photometry was obtained with one of the CSTAR telescopes during 128 days of the 2008 Antarctic winter. We used this photometric data set to derive site statistics for Dome A and to search for variable stars. Thanks to the nearlymore » uninterrupted synoptic coverage, we found six times as many variables as previous surveys with similar magnitude limits. We detected 157 variable stars, of which 55% were unclassified, 27% were likely binaries, and 17% were likely pulsating stars. The latter category includes {delta} Scuti, {gamma} Doradus, and RR Lyrae variables. One variable may be a transiting exoplanet.« less

Telescope Array Results on UHE Cosmic Rays and the Plan

NASA Astrophysics Data System (ADS)

Sagawa, Hiroyuki

The Telescope Array (TA) is the largest experiment in the Northern Hemisphere studying the origin and nature of ultra-high-energy cosmic rays. The TA detector consists of a surface array of 507 scintillation counters covering approximately 700 km2, and 38 fluorescence telescopes located at three sites looking over the surface array. Here, recent TA results using the first five years of data and our ongoing and near-future plans are presented.

Utilization of a Curved Local Surface Array in a 3.5m Wide field of View Telescope

DTIC Science & Technology

2013-09-01

ABSTRACT Wide field of view optical telescopes have a range of uses for both astronomical and space -surveillance purposes. In designing these...Agency (DARPA) 3.5-m Space Surveillance Telescope (SST)), the choice was made to curve the array to best satisfy the stressing telescope performance...dramatically improves the nation’s space surveillance capabilities. This paper will discuss the implementation of the curved focal-surface array, the

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

NASA Astrophysics Data System (ADS)

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 telescope control and monitoring.

An Array of Optical Receivers for Deep-Space Communications

NASA Technical Reports Server (NTRS)

Vilnrotter, Chi-Wung; Srinivasan, Meera; Andrews, Kenneth

2007-01-01

An array of small optical receivers is proposed as an alternative to a single large optical receiver for high-data-rate communications in NASA s Deep Space Network (DSN). Because the telescope for a single receiver capable of satisfying DSN requirements must be greater than 10 m in diameter, the design, building, and testing of the telescope would be very difficult and expensive. The proposed array would utilize commercially available telescopes of 1-m or smaller diameter and, therefore, could be developed and verified with considerably less difficulty and expense. The essential difference between a single-aperture optical-communications receiver and an optical-array receiver is that a single-aperture receiver focuses all of the light energy it collects onto the surface of an optical detector, whereas an array receiver focuses portions of the total collected energy onto separate detectors, optically detects each fractional energy component, then combines the electrical signal from the array of detector outputs to form the observable, or "decision statistic," used to decode the transmitted data. A conceptual block diagram identifying the key components of the optical-array receiver suitable for deep-space telemetry reception is shown in the figure. The most conspicuous feature of the receiver is the large number of small- to medium-size telescopes, with individual apertures and number of telescopes selected to make up the desired total collecting area. This array of telescopes is envisioned to be fully computer- controlled via the user interface and prediction-driven to achieve rough pointing and tracking of the desired spacecraft. Fine-pointing and tracking functions then take over to keep each telescope pointed toward the source, despite imperfect pointing predictions, telescope-drive errors, and vibration caused by wind.

Telescope Array Low energy Extension: TALE

NASA Astrophysics Data System (ADS)

Ogio, Shoichi

TALE, the Telescope Array Low Energy extension was designed to lower the energy threshold to about 1016.5 eV. TALE has a surface detector (SD) array made up of 103 scintillation counters (40 with 400 m spacing, 36 with 600 m spacing and 27 with 1.2 km spacing) and a Fluorescence Detector (FD) station consisting of ten FD telescopes working with the Telescope Array Middle Drum FD station, which is made up of 14 telescopes. TALE-FD full operation started in 2013 and the SD array was partially-completed with 16 SDs and continues the operation from 2014. We will describe the history and the current status of the detectors and will make a brief report about the FD and the hybrid analysis results. TALE detector will be completed as a hybrid air shower detector in 2018. We will report the technical details of the detectors, the schedule and the expected performances.

History of Hubble Space Telescope (HST)

NASA Image and Video Library

1985-01-01

This is a view of a solar cell blanket deployed on a water table during the Solar Array deployment test. The Hubble Space Telescope (HST) Solar Arrays provide power to the spacecraft. The arrays are mounted on opposite sides of the HST, on the forward shell of the Support Systems Module. Each array stands on a 4-foot mast that supports a retractable wing of solar panels 40-feet (12.1-meters) long and 8.2-feet (2.5-meters) wide, in full extension. The arrays rotate so that the solar cells face the Sun as much as possible to harness the Sun's energy. The Space Telescope Operations Control Center at the Goddard Space Center operates the array, extending the panels and maneuvering the spacecraft to focus maximum sunlight on the arrays. 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 Solar Array was designed by the European Space Agency and built by British Aerospace. The Marshall Space Flight Center had overall responsibility for design, development, and construction of the HST.

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

NASA Astrophysics Data System (ADS)

Dournaux, J. L.; De Franco, A.; Laporte, P.; White, R.; Greenshaw, T.; Sol, H.; Abchiche, A.; Allan, D.; Amans, J. P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J. J.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M.; De Frondat, F.; Dumas, D.; Ernenwein, J. P.; Fasola, G.; Funk, S.; Gaudemard, J.; Graham, J. A.; Gironnet, J.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J. M.; Jégouzo, I.; Jogler, T.; Kawashima, T.; Kraus, M.; Lapington, J. S.; Lefaucheur, J.; Markoff, S.; Melse, T.; Morhrmann, L.; Molnyeux, P.; Nolan, S. J.; Okumura, A.; Parsons, R. D.; Ross, D.; Rowell, G.; Sato, Y.; Sayède, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Trichard, C.; Vink, J.; Watson, J.; Yamane, N.; Zech, A.; Zink, A.; CTA Consortium

2017-02-01

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,

The Gamma-ray Cherenkov Telescope, an end-to end Schwarzschild-Couder telescope prototype proposed for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Dournaux, J. L.; Abchiche, A.; Allan, D.; Amans, J. P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Dangeon, L.; Daniel, M. K.; De Franco, A.; De Frondat, F.; Dumas, D.; Ernenwein, J. P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hameau, B.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J. M.; Jégouzo, I.; Jogler, T.; Kawashima, T.; Kraush, M.; Lapington, J. S.; Laporte, P.; Lefaucheur, J.; Markoff, S.; Melse, T.; Mohrmann, L.; Molyneux, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayède, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Trichard, C.; Vink, J.; Watson, J. J.; White, R.; Yamane, N.; Zech, A.; Zink, A.

2016-08-01

The GCT (Gamma-ray Cherenkov Telescope) is a dual-mirror prototype of Small-Sized-Telescopes proposed for the Cherenkov Telescope Array (CTA) and made by an Australian-Dutch-French-German-Indian-Japanese-UK-US consortium. The integration of this end-to-end telescope was achieved in 2015. On-site tests and measurements of the first Cherenkov images on the night sky began on November 2015. This contribution describes the telescope and plans for the pre-production and a large scale production within CTA.

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

NASA Astrophysics Data System (ADS)

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.

The ASTRI mini-array software system (MASS) implementation: a proposal for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Tanci, Claudio; Tosti, Gino; Conforti, Vito; Schwarz, Joseph; Antolini, Elisa; Antonelli, L. A.; Bulgarelli, Andrea; Bigongiari, Ciro; Bruno, Pietro; Canestrari, Rodolfo; Capalbi, Milvia; Cascone, Enrico; Catalano, Osvaldo; Di Paola, Andrea; Di Pierro, Federico; Fioretti, Valentina; Gallozzi, Stefano; Gardiol, Daniele; Gianotti, Fulvio; Giro, Enrico; Grillo, Alessandro; La Palombara, Nicola; Leto, Giuseppe; Lombardi, Saverio; Maccarone, Maria C.; Pareschi, Giovanni; Russo, Federico; Sangiorgi, Pierluca; Scuderi, Salvo; Stringhetti, Luca; Testa, Vincenzo; Trifoglio, Massimo; Vercellone, Stefano; Zoli, Andrea

2016-08-01

The ASTRI mini-array, composed of nine small-size dual mirror (SST-2M) telescopes, has been proposed to be installed at the southern site of the Cherenkov Telescope Array (CTA), as a set of preproduction units of the CTA observatory. The ASTRI mini-array is a collaborative and international effort carried out by Italy, Brazil and South Africa and led by the Italian National Institute of Astrophysics, INAF. We present the main features of the current implementation of the Mini-Array Software System (MASS) now in use for the activities of the ASTRI SST-2M telescope prototype located at the INAF observing station on Mt. Etna, Italy and the characteristics that make it a prototype for the CTA control software system. CTA Data Management (CTADATA) and CTA Array Control and Data Acquisition (CTA-ACTL) requirements and guidelines as well as the ASTRI use cases were considered in the MASS design, most of its features are derived from the Atacama Large Millimeter/sub-millimeter Array Control software. The MASS will provide a set of tools to manage all onsite operations of the ASTRI mini-array in order to perform the observations specified in the short term schedule (including monitoring and controlling all the hardware components of each telescope and calibration device), to analyze the acquired data online and to store/retrieve all the data products to/from the onsite repository.

An image-based array trigger for imaging atmospheric Cherenkov telescope arrays

NASA Astrophysics Data System (ADS)

Dickinson, Hugh; Krennrich, Frank; Weinstein, Amanda; Eisch, Jonathan; Byrum, Karen; Anderson, John; Drake, Gary

2018-05-01

It is anticipated that forthcoming, next generation, atmospheric Cherenkov telescope arrays will include a number of medium-sized telescopes that are constructed using a dual-mirror Schwarzschild-Couder configuration. These telescopes will sample a wide (8 °) field of view using a densely pixelated camera comprising over 104 individual readout channels. A readout frequency congruent with the expected single-telescope trigger rates would result in substantial data rates. To ameliorate these data rates, a novel, hardware-level Distributed Intelligent Array Trigger (DIAT) is envisioned. A copy of the DIAT operates autonomously at each telescope and uses reduced resolution imaging data from a limited subset of nearby telescopes to veto events prior to camera readout and any subsequent network transmission of camera data that is required for centralized storage or aggregation. We present the results of Monte-Carlo simulations that evaluate the efficacy of a "Parallax width" discriminator that can be used by the DIAT to efficiently distinguish between genuine gamma-ray initiated events and unwanted background events that are initiated by hadronic cosmic rays.

The hybrid energy spectrum of Telescope Array's Middle Drum Detector and surface array

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M. G.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2015-08-01

The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.

Instrumentation for single-dish observations with The Greenland Telescope

NASA Astrophysics Data System (ADS)

Grimes, Paul K.; Asada, K.; Blundell, R.; Burgos, R.; Chang, H.-H.; Chen, M. T.; Goldie, D.; Groppi, C.; Han, C. C.; Ho, P. T. P.; Huang, Y. D.; Inoue, M.; Kubo, D.; Koch, P.; Leech, J.; de Lera Acedo, E.; Martin-Cocher, P.; Nishioka, H.; Nakamura, M.; Matsushita, S.; Paine, S. N.; Patel, N.; Raffin, P.; Snow, W.; Sridharan, T. K.; Srinivasan, R.; Thomas, C. N.; Tong, E.; Wang, M.-J.; Wheeler, C.; Withington, S.; Yassin, G.; Zeng, L.-Z.

2014-07-01

The Greenland Telescope project will deploy and operate a 12m sub-millimeter telescope at the highest point of the Greenland i e sheet. The Greenland Telescope project is a joint venture between the Smithsonian As- trophysical Observatory (SAO) and the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA). In this paper we discuss the concepts, specifications, and science goals of the instruments being developed for single-dish observations with the Greenland Telescope, and the coupling optics required to couple both them and the mm-VLBI receivers to antenna. The project will outfit the ALMA North America prototype antenna for Arctic operations and deploy it to Summit Station,1 a NSF operated Arctic station at 3,100m above MSL on the Greenland I e Sheet. This site is exceptionally dry, and promises to be an excellent site for sub-millimeter astronomical observations. The main science goal of the Greenland Telescope is to carry out millimeter VLBI observations alongside other telescopes in Europe and the Americas, with the aim of resolving the event horizon of the super-massive black hole at the enter of M87. The Greenland Telescope will also be outfitted for single-dish observations from the millimeter-wave to Tera-hertz bands. In this paper we will discuss the proposed instruments that are currently in development for the Greenland Telescope - 350 GHz and 650 GHz heterodyne array receivers; 1.4 THz HEB array receivers and a W-band bolometric spectrometer. SAO is leading the development of two heterodyne array instruments for the Greenland Telescope, a 48- pixel, 325-375 GHz SIS array receiver, and a 4 pixel, 1.4 THz HEB array receiver. A key science goal for these instruments is the mapping of ortho and para H2D+ in old protostellar ores, as well as general mapping of CO and other transitions in molecular louds. An 8-pixel prototype module for the 350 GHz array is currently being built for laboratory and operational testing on the Greenland Telescope. Arizona State University are developing a 650 GHz 256 pixel SIS array receiver based on the KAPPa SIS mixer array technology and ASIAA are developing 1.4 THz HEB single pixel and array receivers. The University of Cambridge and SAO are collaborating on the development of the CAMbridge Emission Line Surveyor (CAMELS), a W-band `on- hip' spectrometer instrument with a spectral resolution of R ~ 3000. CAMELS will consist of two pairs of horn antennas, feeding super conducting niobium nitride filter banks read by tantalum based Kinetic Inductance Detectors.

Pierre Auger Observatory and Telescope Array: Joint Contributions to the 33rd International Cosmic Ray Conference (ICRC 2013)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abu-Zayyad, T.; et al.

2013-10-02

Joint contributions of the Pierre Auger and Telescope Array Collaborations to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013: cross-calibration of the fluorescence telescopes, large scale anisotropies and mass composition.

Dual-mode disturbance-accommodating pointing controller for Hubble Space Telescope

NASA Astrophysics Data System (ADS)

Addington, Stewart I.; Johnson, C. D.

1995-03-01

Cyclic thermal expansions and mechanical stiction effects in the solar arrays on the Hubble Space Telescope (HST) are triggering repeated occurrences of damped, relaxation-type flex-body vibrations of the solar arrays. Those solar array vibrations are, in turn, causing unwanted deviations of the telescope from its specified pointing direction. In this paper we propose two strategies one can adopt in designing a telescope-pointing controller to cope with the aforementioned disturbances: 1) a total isolation (TI) control strategy whereby the HST controller torques are designed to adaptively counteract and cancel out the persistent disturbing torques that are causing the unwanted telescope motions and 2) an array damping (AD) control strategy whereby the HST controller torques are used to actively augment the natural dampening of the solar array vibrations and the attendant telescope motions, between triggerings of the stiction-related flex-body relaxation oscillations. Using the principles of disturbance accommodation control theory, a dual-mode controller for a generic, planar-motion (single-axis) model of the HST is proposed. This controller incorporates both the TI and AD modes of disturbance accommodation. Simulation studies of the closed-loop system using generic parameter values clearly indicate, qualitatively, the enhanced pointing performance such a controller can achieve.

Laser Welding Dissimilar Reflective Alloys

NASA Technical Reports Server (NTRS)

Mccay, M. H.; Gopinathan, S.; Kahlen, F.; Speigel, L.

1993-01-01

This project, jointly sponsored by Rocketdyne and CSTAR, involves the development of laser joining of materials which have heretofore been impractical to bond. Of particular interest are joints between stainless steel and copper and also aluminum 6061 to aluminum 2219. CSTAR has a unique opportunity in this area since both the process and development and diagnostics are of interest to industry. Initial results using the pulse tailored laser welding technique developed in CLA for joining crack sensitive materials have proven promising for the aluminum joints based upon metallurgical and electronic microprobe analysis. A declaration of success requires additional mechanical testing. A CW technique has been applied to the stainless-copper joining with some preliminary success. These joints are of significant interest for aeronautics and rocket propulsion applications and the project is expected to continue.

Laser welding dissimilar reflective alloys

NASA Astrophysics Data System (ADS)

McCay, M. H.; Gopinathan, S.; Kahlen, F.; Speigel, L.

1993-01-01

This project, jointly sponsored by Rocketdyne and CSTAR, involves the development of laser joining of materials which have heretofore been impractical to bond. Of particular interest are joints between stainless steel and copper and also aluminum 6061 to aluminum 2219. CSTAR has a unique opportunity in this area since both the process and development and diagnostics are of interest to industry. Initial results using the pulse tailored laser welding technique developed in CLA for joining crack sensitive materials have proven promising for the aluminum joints based upon metallurgical and electronic microprobe analysis. A declaration of success requires additional mechanical testing. A CW technique has been applied to the stainless-copper joining with some preliminary success. These joints are of significant interest for aeronautics and rocket propulsion applications and the project is expected to continue.

Composition Studies with the Telescope Array Surface Detector

NASA Astrophysics Data System (ADS)

Kuznetsov, Mikhail; Piskunov, Maxim; Rubtsov, Grigory; Troitsky, Sergey; Zhezher, Yana

The results on ultra-high-energy cosmic-ray chemical composition based on the data from the Telescope Array surface-detector are presented. The method is based on the multivariate boosted decision tree (BDT) analysis which uses surface-detector observables. The results on average atomic mass in the energy range 1018.0-1020.0 eV are presented. A comparison with the Telescope Array hybrid results and the Pierre Auger Observatory surface detector results is shown.

Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

NASA Technical Reports Server (NTRS)

Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B.; Allen, Maxwell J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C., Jr.

1991-01-01

The Multispectral Solar Telescope Array is a rocket-borne observatory which encompasses seven compact soft X-ray/EUV, multilayer-coated, and two compact far-UV, interference film-coated, Cassegrain and Ritchey-Chretien telescopes. Extensive measurements are presented on the efficiency and spectral bandpass of the X-ray/EUV telescopes. Attention is given to systematic errors and measurement errors.

The Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

NASA Technical Reports Server (NTRS)

Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B. C., Jr.; Allen, Max J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C.

1992-01-01

We have developed seven compact soft X-ray/EUV (XUV) multilayer coated and two compact FUV interference film coated Cassegrain and Ritchey-Chretien telescopes for a rocket borne observatory, the Multi-Spectral Solar Telescope Array. We report here on extensive measurements of the efficiency and spectral bandpass of the XUV telescopes carried out at the Stanford Synchrotron Radiation Laboratory.

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

NASA Astrophysics Data System (ADS)

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.

Report of the Working Design Group

NASA Technical Reports Server (NTRS)

1992-01-01

The engineering study group in the LOUISA workshop was responsible for producing a preliminary general design for an optical synthetic aperture telescope on the Moon. This design is intended to be a test case for focusing continuing design studies. The scope of the design included consideration of the array geometry, individual telescopes, metrology, site attributes, and construction. However, no attempt was made to go into further depth in the design than to cover the essential characteristics of the instrument. The starting point for the array design was the lunar optical array discussed by Burke (1985). His array geometry followed the design and correlation procedure of the 27-element Very Large Array (VLA) radio telescopes near Socorro, New Mexico.

Pulsars Probe the Low-Frequency Gravitational Sky: Pulsar Timing Arrays Basics and Recent Results

NASA Astrophysics Data System (ADS)

Tiburzi, Caterina

2018-03-01

Pulsar Timing Array experiments exploit the clock-like behaviour of an array of millisecond pulsars, with the goal of detecting low-frequency gravitational waves. Pulsar Timing Array experiments have been in operation over the last decade, led by groups in Europe, Australia, and North America. These experiments use the most sensitive radio telescopes in the world, extremely precise pulsar timing models and sophisticated detection algorithms to increase the sensitivity of Pulsar Timing Arrays. No detection of gravitational waves has been made to date with this technique, but Pulsar Timing Array upper limits already contributed to rule out some models of galaxy formation. Moreover, a new generation of radio telescopes, such as the Five hundred metre Aperture Spherical Telescope and, in particular, the Square Kilometre Array, will offer a significant improvement to the Pulsar Timing Array sensitivity. In this article, we review the basic concepts of Pulsar Timing Array experiments, and discuss the latest results from the established Pulsar Timing Array collaborations.

VERITAS: status c.2005

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weekes, T. C.; Atkins, R. W.; Badran, H. M.

2006-07-11

VERITAS (Very Energetic Radiation Imaging Telescope Array System), is one of a new generation of TeV gamma-ray observatories. The current status of its construction is described here. The first two telescopes and cameras have been completed and meet the design specifications; the full array of four telescopes could be operational by the end of 2006.

Microsystem enabled photovoltaic modules and systems

DOEpatents

Nielson, Gregory N.; Sweatt, William C.; Okandan, Murat

2017-09-12

A photovoltaic (PV) module includes an absorber layer coupled to an optic layer. The absorber layer includes an array of PV elements. The optic layer includes a close-packed array of Keplerian telescope elements, each corresponding to one of an array of pupil elements. The Keplerian telescope substantially couple radiation that is incident on their objective surfaces into the corresponding pupil elements. Each pupil element relays radiation that is coupled into it from the corresponding Keplerian telescope element into the corresponding PV element.

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

NASA Technical Reports Server (NTRS)

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

NASA Astrophysics Data System (ADS)

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.

A dual-mode disturbance-accommodating controller for the Hubble Space Telescope

NASA Astrophysics Data System (ADS)

Addington, Stewart; Johnson, C. D.

Cyclic thermal expansions and mechanical stiction effects in the Solar Arrays on the Hubble Space Telescope (HST) are triggering repeated occurrences of damped, relaxation-type flex-body vibrations of the solar arrays. Those solar array vibrations are, in turn, causing unwanted, oscillating disturbance torques on the HST main body, which cause unwanted deviations of the telescope from its specified pointing direction. In this paper we propose two strategies one can adopt in designing a telescope-pointing controller to cope with the aforementioned disturbances: (1) a `total isolation' (TI) control strategy whereby the HST controller torques are designed to adaptively counteract and cancel-out the persistent disturbing torques that are causing the unwanted telescope motions, and (2) an `array damping' (AD) control strategy whereby the HST controller torques are used to actively augment the natural dampening of the solar array vibrations and the attendant telescope motions, between triggerings of the stiction-related flex-body relaxation oscillations. Using the principles of Disturbance-Accommodating Control (DAC) Theory a dual-mode controller for a generic, planar-motion (single-axis) model of the HST is proposed. This controller incorporates both the TI and AD modes of disturbance-accommodation. Simulation studies of the closed-loop system using generic parameter values clearly indicate, qualitatively, the enhanced pointing-performance such a controller can achieve.

Fiber-linked telescope array: description and laboratory tests of a two-channel prototype

NASA Astrophysics Data System (ADS)

Alleman, J. J.; Reynaud, F.; Connes, P.

1995-05-01

We present a complete two-telescope version of a fiber-linked coherent array that is meant to be used for mounting on the dish of a radio telescope. This was built with 20-cm amateur telescopes and includes three different servo subsystems for guiding, nulling of the air path difference, and fiber length control. Laboratory tests of the fully integrated system in front of a star simulator are described.

Discovery of methyl silane and confirmation of silyl cyanide in IRC +10216.

PubMed

Cernicharo, J; Agúndez, M; Velilla Prieto, L; Guélin, M; Pardo, J R; Kahane, C; Marka, C; Kramer, C; Navarro, S; Quintana-Lacaci, G; Fonfría, J P; Marcelino, N; Tercero, B; Moreno, E; Massalkhi, S; Santander-García, M; McCarthy, M C; Gottlieb, C A; Alonso, J L

2017-10-01

We report the discovery in space of methyl silane, CH 3 SiH 3 , from observations of ten rotational transitions between 80 and 350 GHz ( J u from 4 to 16) with the IRAM 30 m radio telescope. The molecule was observed in the envelope of the C-star IRC +10216. The observed profiles and our models for the expected emission of methyl silane suggest that the it is formed in the inner zones of the circumstellar envelope, 1-40 R * , with an abundance of (0.5-1) × 10 -8 relative to H 2 . We also observed several rotational transitions of silyl cyanide (SiH 3 CN), confirming its presence in IRC +10216 in particular, and in space in general. Our models indicate that silyl cyanide is also formed in the inner regions of the envelope, around 20 R * , with an abundance relative to H 2 of 6×10 -10 . The possible formation mechanisms of both species are discussed. We also searched for related chemical species but only upper limits could be obtained.

NECTAR: New electronics for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

The energy spectrum of ultra-high-energy cosmic rays measured by the Telescope Array FADC fluorescence detectors in monocular mode

NASA Astrophysics Data System (ADS)

Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Myers, I.; Minamino, M.; Miyata, K.; Murano, Y.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Sonley, T. J.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2013-08-01

We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array's third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array's middle drum detector and the direct comparison to the high resolution fly's eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: ]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: ] with independent systematic uncertainties.

The single mirror small sized telescope for the Cherenkov telescope array

NASA Astrophysics Data System (ADS)

Heller, M.; Schioppa, E., Jr.; Porcelli, A.; Pujadas, I. Troyano; Ziętara, K.; Della Volpe, D.; Montaruli, T.; Cadoux, F.; Favre, Y.; Aguilar, J. A.; Christov, A.; Prandini, E.; Rajda, P.; Rameez, M.; Bilnik, W.; Błocki, J.; Bogacz, L.; Borkowski, J.; Bulik, T.; Frankowski, A.; Grudzińska, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandat, D.; Marszałek, A.; Miranda, L. D. Medina; Michałowski, J.; Moderski, R.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Pech, M.; Schovanek, P.; Seweryn, K.; Sliusar, V.; Skowron, K.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Walter, R.; Więcek, M.; Zagdański, A.; CTA Consortium

2017-01-01

The Small Size Telescope with Single Mirror (SST-1M) is one of the proposed types of Small Size Telescopes (SST) for the Cherenkov Telescope Array (CTA). About 70 SST telescopes will be part the CTA southern array which will also include Medium Sized Telescopes (MST) in its threshold configuration. Optimized for the detection of gamma rays in the energy range from 5 TeV to 300 TeV, the SST-1M uses a Davies-Cotton optics with a 4 m dish diameter with a field of view of 9°. The Cherenkov light resulting from the interaction of the gamma-rays in the atmosphere is focused onto a 88 cm side-to-side hexagonal photo-detection plane. The latter is composed of 1296 hollow light guides coupled to large area hexagonal silicon photomultipliers (SiPM). The SiPM readout is fully digital readout as for the trigger system. The compact and lightweight design of the SST-1M camera offiers very high performance ideal for gamma-ray observation requirement. In this contribution, the concept, design, performance and status of the first telescope prototype are presented.

Optical Path Difference Fluctations at the CHARA Interferometric Array

NASA Astrophysics Data System (ADS)

Merand, A.; ten Brummelaar, T. A.; McAlister, H. A.; Ridgway, S. T.; Sturmann, J.; Sturmann, L.; Turner, N. H.; Bagnuolo, W. G.; Hrynevych, M.; Shure, M. A.

2001-05-01

Commissioning observations at the CHARA Array have been carried out with the two south telescopes, with a telescope separation of 34 meters. Due to the size of the array (>340 meters across) and the optical delay geometry, the beams travel horizontal distances of approximately 200 meters, with a number of reflections in the telescope coude area and the optical delay and beam combination areas. Stellar and laboratory observations have been analyzed to determine the variations of the optical path, as revealed by shifts in the interference pattern. The power spectra of the OPD variations are diagnostic of the atmospheric turbulence characteristics, and of any internal vibrations in the laboratory. Results of the OPD analysis will be compared to similar studies at other interferometric facilities. The CHARA Array, a six-telescope O/IR interferometric array operated by Georgia State University on Mt. Wilson, Calfornia, was funded by the National Science Foundation, the W.M. Keck Foundation, the David and Lucile Packard Foundation, and Georgia State University.

Imaging phased telescope array study

NASA Technical Reports Server (NTRS)

Harvey, James E.

1989-01-01

The problems encountered in obtaining a wide field-of-view with large, space-based direct imaging phased telescope arrays were considered. After defining some of the critical systems issues, previous relevant work in the literature was reviewed and summarized. An extensive list was made of potential error sources and the error sources were categorized in the form of an error budget tree including optical design errors, optical fabrication errors, assembly and alignment errors, and environmental errors. After choosing a top level image quality requirment as a goal, a preliminary tops-down error budget allocation was performed; then, based upon engineering experience, detailed analysis, or data from the literature, a bottoms-up error budget reallocation was performed in an attempt to achieve an equitable distribution of difficulty in satisfying the various allocations. This exercise provided a realistic allocation for residual off-axis optical design errors in the presence of state-of-the-art optical fabrication and alignment errors. Three different computational techniques were developed for computing the image degradation of phased telescope arrays due to aberrations of the individual telescopes. Parametric studies and sensitivity analyses were then performed for a variety of subaperture configurations and telescope design parameters in an attempt to determine how the off-axis performance of a phased telescope array varies as the telescopes are scaled up in size. The Air Force Weapons Laboratory (AFWL) multipurpose telescope testbed (MMTT) configuration was analyzed in detail with regard to image degradation due to field curvature and distortion of the individual telescopes as they are scaled up in size.

The Advanced Gamma-ray Imaging System (AGIS): Real Time Stereoscopic Array Trigger

NASA Astrophysics Data System (ADS)

Byrum, K.; Anderson, J.; Buckley, J.; Cundiff, T.; Dawson, J.; Drake, G.; Duke, C.; Haberichter, B.; Krawzcynski, H.; Krennrich, F.; Madhavan, A.; Schroedter, M.; Smith, A.

2009-05-01

Future large arrays of Imaging Atmospheric Cherenkov telescopes (IACTs) such as AGIS and CTA are conceived to comprise of 50 - 100 individual telescopes each having a camera with 10**3 to 10**4 pixels. To maximize the capabilities of such IACT arrays with a low energy threshold, a wide field of view and a low background rate, a sophisticated array trigger is required. We describe the design of a stereoscopic array trigger that calculates image parameters and then correlates them across a subset of telescopes. Fast Field Programmable Gate Array technology allows to use lookup tables at the array trigger level to form a real-time pattern recognition trigger tht capitalizes on the multiple view points of the shower at different shower core distances. A proof of principle system is currently under construction. It is based on 400 MHz FPGAs and the goal is for camera trigger rates of up to 10 MHz and a tunable cosmic-ray background suppression at the array level.

Current status of the expanded GRAPES collaboration experiment at Ooty in India

NASA Astrophysics Data System (ADS)

Gupta, S.K.; Anita, H.M.; Iyer, A.; Jagadeesan, P.; Jain, A.; Karthikeyan, S.; Manoharan, P.K.; Mohanty, P.K.; Nayak, P.K.; Rao, B.S.; Ravindran, K.C.; Tanaka, H.; Tonwar, S.C.; Ogio, S.; Okuda, T.; Oshima, A.; Shimizu, N.; Yoshikoshi, T.; Badruddin; Hasan, R.; Ahmad, Shakeel; Mishra, A.P.; Shrivastava, P.K.; Koul, R.; Shah, G.N.; Mir, T.A.; Mufti, S.; Raha, S.; Ghosh, S.; Joarder, P.; Saha, S.; Boruah, K.; Datta, P.; Boruah, P.K.; Baruah, A.G.; Baishya, R.; Saikia, J.; Banerjee, D.; Subramanian, P.; Bhadra, A.; Kumar, S.; Agarwal, R.; Dubey, S.K.; Bhattacharjee, P.

GRAPES-3 experiment employs a high-density array of scintillators and a large area tracking muon telescope. The GRAPES collaboration is being expanded with addition of several major facilities. These include a Cerenkov telescope and low frequency dipole array for the measurement of shower energy. Addition of several modules of muon telescopes to cover a larger area, expansion of the scintillator array with greater separation between detectors. Installation of a neutron monitor is also planned. The current status of the experiment would be summarized.

The Atacama Cosmology Telescope: The Receiver and Instrumentation

NASA Technical Reports Server (NTRS)

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.;

The Cherenkov Telescope Array For Very High-Energy Astrophysics

NASA Astrophysics Data System (ADS)

Kaaret, Philip

2015-08-01

The field of very high energy (VHE) astrophysics had been revolutionized by the results from ground-based gamma-ray telescopes, including the current imaging atmospheric Cherenkov telescope (IACT) arrays: HESS, MAGIC and VERITAS. A worldwide consortium of scientists from 29 countries has formed to propose the Cherenkov Telescope Array (CTA) that will capitalize on the power of this technique to greatly expand the scientific reach of ground-based gamma-ray telescopes. CTA science will include key topics such as the origin of cosmic rays and cosmic particle acceleration, understanding extreme environments in regions close to neutron stars and black holes, and exploring physics frontiers through, e.g., the search for WIMP dark matter, axion-like particles and Lorentz invariance violation. CTA is envisioned to consist of two large arrays of Cherenkov telescopes, one in the southern hemisphere and one in the north. Each array will contain telescopes of different sizes to provide a balance between cost and array performance over an energy range from below 100 GeV to above 100 TeV. Compared to the existing IACT arrays, CTA will have substantially better angular resolution and energy resolution, will cover a much wider energy range, and will have up to an order of magnitude better sensitivity. CTA will also be operated as an open observatory and high-level CTA data will be placed into the public domain; these aspects will enable broad participation in CTA science from the worldwide scientific community to fully capitalize on CTA's potential. This talk will: 1) review the scientific motivation and capabilities of CTA, 2) provide an overview of the technical design and the status of prototype development, and 3) summarize the current status of the project in terms of its proposed organization and timeline. The plans for access to CTA data and opportunities to propose for CTA observing time will be highlighed.Presented on behalf of the CTA Consortium.

Monte Carlo performance studies for the site selection of the Cherenkov Telescope Array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hassan, T.; Arrabito, L.; Bernlöhr, K.

The Cherenkov Telescope Array (CTA) represents the next generation of ground-based instruments for very-high-energy (VHE) gamma-ray astronomy, aimed at improving on the sensitivity of current-generation experiments by an order of magnitude and providing coverage over four decades of energy. The current CTA design consists of two arrays of tens of imaging atmospheric Cherenkov Telescopes, comprising Small, Medium and Large-Sized Telescopes, with one array located in each of the Northern and Southern Hemispheres. To study the effect of the site choice on the overall CTA performance and support the site evaluation process, detailed Monte Carlo simulations have been performed. These resultsmore » show the impact of different site-related attributes such as altitude, night-sky background and local geomagnetic field on CTA performance for the observation of VHE gamma rays.« less

Monte Carlo performance studies for the site selection of the Cherenkov Telescope Array

DOE PAGES

Hassan, T.; Arrabito, L.; Bernlöhr, K.; ...

2017-05-03

The Cherenkov Telescope Array (CTA) represents the next generation of ground-based instruments for very-high-energy (VHE) gamma-ray astronomy, aimed at improving on the sensitivity of current-generation experiments by an order of magnitude and providing coverage over four decades of energy. The current CTA design consists of two arrays of tens of imaging atmospheric Cherenkov Telescopes, comprising Small, Medium and Large-Sized Telescopes, with one array located in each of the Northern and Southern Hemispheres. To study the effect of the site choice on the overall CTA performance and support the site evaluation process, detailed Monte Carlo simulations have been performed. These resultsmore » show the impact of different site-related attributes such as altitude, night-sky background and local geomagnetic field on CTA performance for the observation of VHE gamma rays.« less

The optical very large array and its moon-based version

NASA Technical Reports Server (NTRS)

Labeyrie, Antoine

1992-01-01

An Optical Very Large Array (OVLA) is currently in early prototyping stages for ground-based sites, such as Mauna Kea and perhaps the VLT site in Chile. Its concept is also suited for a moon-based interferometer. With a ring of bi-dimensionally mobile telescopes, there is maximal flexibility in the aperture pattern, and no need for delay lines. A circular configuration of many free-flying telescopes, TRIO, is also considered for space interferometers. Finally, the principle of gaseous mirrors may become applicable for moon-based optical arrays. Fifteen years after the first coherent linkage of two optical telescopes, the design of an ambitious imaging array, the OVLA, is now well advanced. Two 1.5 m telescopes have been built and now provide astronomical results. Elements of the OVLA are under construction. Although primarily conceived for ground-based sites, the OVLA structure appears to meet the essential requirements for operation on the Moon.

Simulating a Measurement of the 2nd Knee in the Cosmic Ray Spectrum with an Atmospheric Fluorescence Telescope Tower Array

PubMed Central

Liu, Jiali; Yang, Qunyu; Bai, Yunxiang; Cao, Zhen

2014-01-01

A fluorescence telescope tower array has been designed to measure cosmic rays in the energy range of 1017–1018 eV. A full Monte Carlo simulation, including air shower production, light generation and propagation, detector response, electronics, and trigger system, has been developed for that purpose. Using such a simulation tool, the detector configuration, which includes one main tower array and two side-trigger arrays, 24 telescopes in total, has been optimized. The aperture and the event rate have been estimated. Furthermore, the performance of the X max⁡ technique in measuring composition has also been studied. PMID:24737964

Pupil geometry and pupil re-imaging in telescope arrays

NASA Technical Reports Server (NTRS)

Traub, Wesley A.

1990-01-01

This paper considers the issues of lateral and longitudinal pupil geometry in ground-based telescope arrays, such as IOTA. In particular, it is considered whether or not pupil re-imaging is required before beam combination. By considering the paths of rays through the system, an expression is derived for the optical path errors in the combined wavefront as a function of array dimensions, telescope magnification factor, viewing angle, and field-of-view. By examining this expression for the two cases of pupil-plane and image-plane combination, operational limits can be found for any array. As a particular example, it is shown that for IOTA no pupil re-imaging optics will be needed.

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

NASA Astrophysics Data System (ADS)

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.

Mount control system of the ASTRI SST-2M prototype for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Antolini, Elisa; Tosti, Gino; Tanci, Claudio; Bagaglia, Marco; Canestrari, Rodolfo; Cascone, Enrico; Gambini, Giorgio; Nucciarelli, Giuliano; Pareschi, Giovanni; Scuderi, Salvo; Stringhetti, Luca; Busatta, Andrea; Giacomel, Stefano; Marchiori, Gianpietro; Manfrin, Cristiana; Marcuzzi, Enrico; Di Michele, Daniele; Grigolon, Carlo; Guarise, Paolo

2016-08-01

The ASTRI SST-2M telescope is an end-to-end prototype proposed for the Small Size class of Telescopes (SST) of the future Cherenkov Telescope Array (CTA). The prototype is installed in Italy at the INAF observing station located at Serra La Nave on Mount Etna (Sicily) and it was inaugurated in September 2014. This paper presents the software and hardware architecture and development of the system dedicated to the control of the mount, health, safety and monitoring systems of the ASTRI SST-2M telescope prototype. The mount control system installed on the ASTRI SST-2M telescope prototype makes use of standard and widely deployed industrial hardware and software. State of the art of the control and automation industries was selected in order to fulfill the mount related functional and safety requirements with assembly compactness, high reliability, and reduced maintenance. The software package was implemented with the Beckhoff TwinCAT version 3 environment for the software Programmable Logical Controller (PLC), while the control electronics have been chosen in order to maximize the homogeneity and the real time performance of the system. The integration with the high level controller (Telescope Control System) has been carried out by choosing the open platform communications Unified Architecture (UA) protocol, supporting rich data model while offering compatibility with the PLC platform. In this contribution we show how the ASTRI approach for the design and implementation of the mount control system has made the ASTRI SST-2M prototype a standalone intelligent machine, able to fulfill requirements and easy to be integrated in an array configuration such as the future ASTRI mini-array proposed to be installed at the southern site of the Cherenkov Telescope Array (CTA).

Calibration of the Multi-Spectral Solar Telescope Array multilayer mirrors and XUV filters

NASA Technical Reports Server (NTRS)

Allen, Maxwell J.; Willis, Thomas D.; Kankelborg, Charles C.; O'Neal, Ray H.; Martinez-Galarce, Dennis S.; Deforest, Craig E.; Jackson, Lisa; Lindblom, Joakim; Walker, Arthur B. C., Jr.; Barbee, Troy W., Jr.

1993-01-01

The Multi-Spectral Solar Telescope Array (MSSTA), a rocket-borne solar observatory, was successfully flown in May, 1991, obtaining solar images in eight XUV and FUV bands with 12 compact multilayer telescopes. Extensive measurements have recently been carried out on the multilayer telescopes and thin film filters at the Stanford Synchrotron Radiation Laboratory. These measurements are the first high spectral resolution calibrations of the MSSTA instruments. Previous measurements and/or calculations of telescope throughputs have been confirmed with greater accuracy. Results are presented on Mo/Si multilayer bandpass changes with time and experimental potassium bromide and tellurium filters.

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

NASA Astrophysics Data System (ADS)

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.

The Engineering Development Array: A Low Frequency Radio Telescope Utilising SKA Precursor Technology

NASA Astrophysics Data System (ADS)

Wayth, Randall; Sokolowski, Marcin; Booler, Tom; Crosse, Brian; Emrich, David; Grootjans, Robert; Hall, Peter J.; Horsley, Luke; Juswardy, Budi; Kenney, David; Steele, Kim; Sutinjo, Adrian; Tingay, Steven J.; Ung, Daniel; Walker, Mia; Williams, Andrew; Beardsley, A.; Franzen, T. M. O.; Johnston-Hollitt, M.; Kaplan, D. L.; Morales, M. F.; Pallot, D.; Trott, C. M.; Wu, C.

2017-08-01

We describe the design and performance of the Engineering Development Array, which is a low-frequency radio telescope comprising 256 dual-polarisation dipole antennas working as a phased array. The Engineering Development Array was conceived of, developed, and deployed in just 18 months via re-use of Square Kilometre Array precursor technology and expertise, specifically from the Murchison Widefield Array radio telescope. Using drift scans and a model for the sky brightness temperature at low frequencies, we have derived the Engineering Development Array's receiver temperature as a function of frequency. The Engineering Development Array is shown to be sky-noise limited over most of the frequency range measured between 60 and 240 MHz. By using the Engineering Development Array in interferometric mode with the Murchison Widefield Array, we used calibrated visibilities to measure the absolute sensitivity of the array. The measured array sensitivity matches very well with a model based on the array layout and measured receiver temperature. The results demonstrate the practicality and feasibility of using Murchison Widefield Array-style precursor technology for Square Kilometre Array-scale stations. The modular architecture of the Engineering Development Array allows upgrades to the array to be rolled out in a staged approach. Future improvements to the Engineering Development Array include replacing the second stage beamformer with a fully digital system, and to transition to using RF-over-fibre for the signal output from first stage beamformers.

The Cherenkov Telescope Array: Exploring the Very-high-energy Sky from ESO's Paranal Site

NASA Astrophysics Data System (ADS)

Hofmann, W.

2017-06-01

The Cherenkov Telescope Array (CTA) is a next-generation observatory for ground-based very-high-energy gamma-ray astronomy, using the imaging atmospheric Cherenkov technique to detect and reconstruct gamma-ray induced air showers. The CTA project is planning to deploy 19 telescopes on its northern La Palma site, and 99 telescopes on its southern site at Paranal, covering the 20 GeV to 300 TeV energy domain and offering vastly improved performance compared to currently operating Cherenkov telescopes. The combination of three different telescope sizes (23-, 12- and 4-metre) allows cost-effective coverage of the wide energy range. CTA will be operated as a user facility, dividing observation time between a guest observer programme and large Key Science Projects (KSPs), and the data will be made public after a one-year proprietary period. The history of the project, the implementation of the arrays, and some of the major science goals and KSPs, are briefly summarised.

The single mirror small size telescope (SST-1M) of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Aguilar, J. A.; Bilnik, W.; Borkowski, J.; Cadoux, F.; Christov, A.; della Volpe, D.; Favre, Y.; Heller, M.; Kasperek, J.; Lyard, E.; Marszałek, A.; Moderski, R.; Montaruli, T.; Porcelli, A.; Prandini, E.; Rajda, P.; Rameez, M.; Schioppa, E., Jr.; Troyano Pujadas, I.; Zietara, K.; Blocki, J.; Bogacz, L.; Bulik, T.; Frankowski, A.; Grudzinska, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Lalik, K.; Mach, E.; Mandat, D.; Michałowski, J.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Pech, M.; Schovanek, P.; Seweryn, K.; Skowron, K.; Sliusar, V.; Stawarz, L.; Stodulska, M.; Stodulski, M.; Toscano, S.; Walter, R.; WiÈ©cek, M.; Zagdański, A.

2016-07-01

The Small Size Telescope with Single Mirror (SST-1M) is one of the proposed types of Small Size Telescopes (SST) for the Cherenkov Telescope Array (CTA). The CTA south array will be composed of about 100 telescopes, out of which about 70 are of SST class, which are optimized for the detection of gamma rays in the energy range from 5 TeV to 300 TeV. The SST-1M implements a Davies-Cotton optics with a 4 m dish diameter with a field of view of 9°. The Cherenkov light produced in atmospheric showers is focused onto a 88 cm wide hexagonal photo-detection plane, composed of 1296 custom designed large area hexagonal silicon photomultipliers (SiPM) and a fully digital readout and trigger system. The SST-1M camera has been designed to provide high performance in a robust as well as compact and lightweight design. In this contribution, we review the different steps that led to the realization of the telescope prototype and its innovative camera.

Conceptual design of a coherent optical system of modular imaging collectors (COSMIC). [telescope array deployed by space shuttle in 1990's

NASA Technical Reports Server (NTRS)

Nein, M. E.; Davis, B. G.

1982-01-01

The Coherent Optical System of Modular Imaging Collectors (COSMIC) is the design concept for a phase-coherent optical telescope array that may be placed in earth orbit by the Space Shuttle in the 1990s. The initial system module is a minimum redundancy array whose photon collecting area is three times larger than that of the Space Telescope, and possesses a one-dimensional resoution of better than 0.01 arcsec in the visible range. Thermal structural requirements are assessed. Although the coherent beam combination requirements will be met by an active control system, the COSMIC structural/thermal design must meet more stringent performance criteria than even those of the Space Telescope.

GCT, the Gamma-ray Cherenkov Telescope for multi-TeV science with the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Sol, H.; Dournaux, J.-L.; Laporte, P.

2016-12-01

GCT is a gamma-ray telescope proposed for the high-energy section of the Cherenkov Telescope Array (CTA). A GCT prototype telescope has been designed, built and installed at the Observatoire de Paris in Meudon. Equipped with the first GCT prototype camera developed by an international collaboration, the complete GCT prototype was inaugurated in December 2015, after getting its first Cherenkov light on the night sky in November. The phase of tests, assessment, and optimisation is now coming to an end. Pre-production of the first GCT telescopes and cameras should start in 2017, for an installation on the Chilean site of CTA in 2018.

The gamma-ray Cherenkov telescope for the Cherenkov telescope array

NASA Astrophysics Data System (ADS)

Tibaldo, L.; Abchiche, A.; Allan, D.; Amans, J.-P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M. K.; De Franco, A.; De Frondat, F.; Dournaux, J.-L.; Dumas, D.; Ernenwein, J.-P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J.-M.; Jankowsky, D.; Jegouzo, I.; Jogler, T.; Kraus, M.; Lapington, J. S.; Laporte, P.; Lefaucheur, J.; Markoff, S.; Melse, T.; Mohrmann, L.; Molyneux, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayède, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Trichard, C.; Vink, J.; Watson, J. J.; White, R.; Yamane, N.; Zech, A.; Zink, A.; Zorn, J.; CTA Consortium

2017-01-01

The Cherenkov Telescope Array (CTA) is a forthcoming ground-based observatory for very-high-energy gamma rays. CTA will consist of two arrays of imaging atmospheric Cherenkov telescopes in the Northern and Southern hemispheres, and will combine telescopes of different types to achieve unprecedented performance and energy coverage. The Gamma-ray Cherenkov Telescope (GCT) is one of the small-sized telescopes proposed for CTA to explore the energy range from a few TeV to hundreds of TeV with a field of view ≳ 8° and angular resolution of a few arcminutes. The GCT design features dual-mirror Schwarzschild-Couder optics and a compact camera based on densely-pixelated photodetectors as well as custom electronics. In this contribution we provide an overview of the GCT project with focus on prototype development and testing that is currently ongoing. We present results obtained during the first on-telescope campaign in late 2015 at the Observatoire de Paris-Meudon, during which we recorded the first Cherenkov images from atmospheric showers with the GCT multi-anode photomultiplier camera prototype. We also discuss the development of a second GCT camera prototype with silicon photomultipliers as photosensors, and plans toward a contribution to the realisation of CTA.

The ASTRI/CTA mini-array software system

NASA Astrophysics Data System (ADS)

Tosti, Gino; Schwarz, Joseph; Antonelli, Lucio Angelo; Trifoglio, Massimo; Catalano, Osvaldo; Maccarone, Maria Concetta; Leto, Giuseppe; Gianotti, Fulvio; Canestrari, Rodolfo; Giro, Enrico; Fiorini, Mauro; La Palombara, Nicola; Pareschi, Giovanni; Stringhetti, Luca; Vercellone, Stefano; Conforti, Vito; Tanci, Claudio; Bruno, Pietro; Grillo, Alessandro; Testa, Vincenzo; di Paola, Andrea; Gallozzi, Stefano

2014-07-01

ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project financed by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. The main goals of the ASTRI project are the realization of an end-to-end prototype of a Small Size Telescope (SST) for the Cherenkov Telescope Array (CTA) in a dual- mirror configuration (SST-2M) and, subsequently, of a mini-array comprising seven SST-2M telescopes. The mini-array will be placed at the final CTA Southern Site, which will be part of the CTA seed array, around which the whole CTA observatory will be developed. The Mini-Array Software System (MASS) will provide a comprehensive set of tools to prepare an observing proposal, to perform the observations specified therein (monitoring and controlling all the hardware components of each telescope), to analyze the acquired data online and to store/retrieve all the data products to/from the archive. Here we present the main features of the MASS and its first version, to be tested on the ASTRI SST-2M prototype that will be installed at the INAF observing station located at Serra La Nave on Mount Etna in Sicily.

Operation and performance of the EEE network array for the detection of cosmic rays

NASA Astrophysics Data System (ADS)

Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferraro, A.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Licciulli, F.; Maggiora, A.; Maragoto Rodriguez, O.; Maron, G.; Martelli, B.; Mazziotta, M. N.; Miozzi, S.; Nania, R.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Park, W.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Stori, L.; Taiuti, M.; Terreni, G.; Visnyei, O. B.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

2017-02-01

The EEE (Extreme Energy Events) Project is an experiment for the detection of cosmic ray muons by means of a sparse array of telescopes, each made of three Multigap Resistive Plate Chambers (MRPC), distributed over all the Italian territory and at CERN. The main scientific goals of the Project are the investigation of the properties of the local muon flux, the detection of Extensive Air Showers (EAS) and the search for long-distance correlations between far telescopes. The Project is also characterized by a strong educational and outreach aspect since the telescopes are managed by teams of students and teachers who had previously constructed them at CERN. In this paper an overall description of the experiment is given, including the design, construction and performance of the telescopes. The operation of the whole array, which currently consists of more than 50 telescopes, is also presented by showing the most recent physics results.

Chinese SLE Treatment and Research group (CSTAR) registry VII: prevalence and clinical significance of serositis in Chinese patients with systemic lupus erythematosus.

PubMed

Zhao, J; Bai, W; Zhu, P; Zhang, X; Liu, S; Wu, L; Ma, L; Bi, L; Zuo, X; Sun, L; Huang, C; Tian, X; Li, M; Zhao, Y; Zeng, X

2016-05-01

To investigate both the prevalence and clinical characteristics of serositis in Chinese patients with systemic lupus erythematosus (SLE) in a large cohort in the Chinese SLE Treatment and Research group (CSTAR) database. A prospective cross-sectional study of patients with SLE was conducted based on the data from the CSTAR registry. Serositis was defined according to the 1999 revised American College of Rheumatology (ACR) criteria for SLE - that is, pleuritis/pleural effusion and/or pericarditis/pericardial effusion detected by echocardiography, chest X-ray or chest computerized tomography (CT) scan. Peritonitis/peritoneal effusion were confirmed by abdominal ultrasonography. We analysed the prevalence and clinical associations of serositis with demographic data, organ involvements, laboratory findings and SLE disease activity. Of 2104 patients with SLE, 345 were diagnosed with serositis. The prevalence of lupus nephritis (LN), interstitial lung disease and pulmonary arterial hypertension, as well as the presence of leukocytopenia, thrombocytopenia, hypocomplementemia and anti-dsDNA antibodies was significantly higher in patients with serositis (P < 0.05). Significantly higher SLE disease activity scores were found in patients with serositis compared to those patients without serositis (P < 0.05). Lupus-related peritonitis had similar clinical manifestations and laboratory profiles as serositis caused by SLE. There is a significant association of nephropathy, interstitial lung disease, pulmonary arterial hypertension, hypocomplementemia, leukocytopenia, thrombocytopenia and elevated anti-dsDNA antibodies with serositis. The results suggest that higher SLE disease activity contributes to serositis development, and should be treated aggressively. © The Author(s) 2016.

NASA's Spitzer Space Telescope's Operational Mission Experience

NASA Technical Reports Server (NTRS)

Wilson, Robert K.; Scott, Charles P.

2006-01-01

New Generation of Detector Arrays(100 to 10,000 Gain in Capability over Previous Infrared Space Missions). IRAC: 256 x 256 pixel arrays operating at 3.6 microns, 4.5 microns, 5.8 microns, 8.0 microns. MIPS: Photometer with 3 sets of arrays operating at 24 microns, 70 microns and 160 microns. 128 x 128; 32 x 32 and 2 x 20 arrays. Spectrometer with 50-100 micron capabilities. IRS: 4 Array (128x128 pixel) Spectrograph, 4 -40 microns. Warm Launch Architecture: All other Infrared Missions launched with both the telescope and scientific instrument payload within the cryostat or Dewar. Passive cooling used to cool outer shell to approx.40 K. Cryogenic Boil-off then cools telescope to required 5.5K. Earth Trailing Heliocentric Orbit: Increased observing efficiency, simplification of observation planning, removes earth as heat source.

Concept design of an 80-dual polarization element cryogenic phased array camera for the Arecibo Radio Telescope

NASA Astrophysics Data System (ADS)

Cortes-Medellin, German; Parshley, Stephen; Campbell, Donald B.; Warnick, Karl F.; Jeffs, Brian D.; Ganesh, Rajagopalan

2016-08-01

This paper presents the current concept design for ALPACA (Advanced L-Band Phased Array Camera for Arecibo) an L-Band cryo-phased array instrument proposed for the 305 m radio telescope of Arecibo. It includes the cryogenically cooled front-end with 160 low noise amplifiers, a RF-over-fiber signal transport and a digital beam former with an instantaneous bandwidth of 312.5 MHz per channel. The camera will digitally form 40 simultaneous beams inside the available field of view of the Arecibo telescope optics, with an expected system temperature goal of 30 K.

Design and Deployment of a Multichroic Polarimeter Array on the Atacama Cosmology Telescope

NASA Technical Reports Server (NTRS)

Datta, R.; Austermann, J.; Beall, J. A.; Becker, D.; Coughlin, K. P.; Duff, S. M.; Gallardo, P.A.; Grace, E.; Hasselfield, M.; Henderson, S. W.;

Design and Deployment of a Multichroic Polarimeter Array on the Atacama Cosmology Telescope

NASA Astrophysics Data System (ADS)

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

2016-08-01

We present the design and the preliminary on-sky performance with respect to beams and passbands of a multichroic polarimeter array covering the 90 and 146 GHz cosmic microwave background bands and its enabling broad-band optical system recently deployed on the Atacama Cosmology Telescope (ACT). The constituent pixels are feedhorn-coupled multichroic polarimeters fabricated at NIST. This array is coupled to the ACT telescope via a set of three silicon lenses incorporating novel broad-band metamaterial anti-reflection coatings. This receiver represents the first multichroic detector array deployed for a CMB experiment and paves the way for the extensive use of multichroic detectors and broad-band optical systems in the next generation of CMB experiments.

Highlights from the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Sagawa, H.

2014-10-01

The Telescope Array (TA) is the largest experiment in the Northern Hemisphere currently studying the origin and nature of ultra-high-energy cosmic rays above ˜1018 eV by measuring their energy spectrum, mass composition, and arrival directions. It is located in the western desert of central Utah, USA. The TA detector consists of a surface array of 507 scintillation counters, deployed on a square grid of 1.2-km spacing that covers approximately 700 km2, and 38 fluorescence telescopes located at three sites looking over the surface array. The TA commenced hybrid observation with both sets of detectors in 2008. Here, we present recent results from these 5 years of data and outline our ongoing and near future plans.

Innovative enclosure dome/observing aperture system design for the MROI Array Telescopes

NASA Astrophysics Data System (ADS)

Busatta, A.; Marchiori, G.; Mian, S.; Payne, I.; Pozzobon, M.

2010-07-01

The close-pack array of the MROI necessitated an original design for the Unit Telescope Enclosure (UTE) at Magdalena Ridge Observatory. The Magdalena Ridge Observatory Interferometer (MROI) is a project which comprises an array of up to ten (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. The most compact configuration includes all ten telescopes, several of which are at a relative distance of less than 8m center to center from each other. Since the minimum angle of the field of regard is 30° with respect to the horizon, it is difficult to prevent optical blockage caused by adjacent UTEs in this compact array. This paper presents the design constraints inherent in meeting the requirement for the close-pack array. An innovative design enclosure was created which incorporates an unique dome/observing aperture system. The description of this system focuses on how the field of regard requirement led to an unique and highly innovative concept that had to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). Finally, we describe the wide use of composites materials and structures (e.g. glass/carbon fibres, sandwich panels etc.) on the aperture system which represents the only way to guarantee adequate thermal and environmental protection, compactness, structural stability and limited power consumption due to reduced mass.

Calibration strategies for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

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.

A new concept of imaging system: telescope windows

NASA Astrophysics Data System (ADS)

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.

A decametric wavelength radio telescope for interplanetary scintillation observations

NASA Technical Reports Server (NTRS)

Cronyn, W. M.; Shawhan, S. D.

1975-01-01

A phased array, electrically steerable radio telescope (with a total collecting area of 18 acres), constructed for the purpose of remotely sensing electron density irregularity structure in the solar wind, is presented. The radio telescope is able to locate, map, and track large scale features of the solar wind, such as streams and blast waves, by monitoring a large grid of natural radio sources subject to rapid intensity fluctuation (interplanetary scintillation) caused by the irregularity structure. Observations verify the performance of the array, the receiver, and the scintillation signal processing circuitry of the telescope.

Prospects for gravitational wave astronomy with next generation large-scale pulsar timing arrays

NASA Astrophysics Data System (ADS)

Wang, Yan; Mohanty, Soumya D.

2018-02-01

Next generation radio telescopes, namely the Five-hundred-meter Aperture Spherical Telescope (FAST) and the Square Kilometer Array (SKA), will revolutionize the pulsar timing arrays (PTAs) based gravitational wave (GW) searches. We review some of the characteristics of FAST and SKA, and the resulting PTAs, that are pertinent to the detection of gravitational wave signals from individual supermassive black hole binaries.

Software design and code generation for the engineering graphical user interface of the ASTRI SST-2M prototype for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Tanci, Claudio; Tosti, Gino; Antolini, Elisa; Gambini, Giorgio F.; Bruno, Pietro; Canestrari, Rodolfo; Conforti, Vito; Lombardi, Saverio; Russo, Federico; Sangiorgi, Pierluca; Scuderi, Salvatore

2016-08-01

ASTRI is an on-going project developed in the framework of the Cherenkov Telescope Array (CTA). An end- to-end prototype of a dual-mirror small-size telescope (SST-2M) has been installed at the INAF observing station on Mt. Etna, Italy. The next step is the development of the ASTRI mini-array composed of nine ASTRI SST-2M telescopes proposed to be installed at the CTA southern site. The ASTRI mini-array is a collaborative and international effort carried on by Italy, Brazil and South-Africa and led by the Italian National Institute of Astrophysics, INAF. To control the ASTRI telescopes, a specific ASTRI Mini-Array Software System (MASS) was designed using a scalable and distributed architecture to monitor all the hardware devices for the telescopes. Using code generation we built automatically from the ASTRI Interface Control Documents a set of communication libraries and extensive Graphical User Interfaces that provide full access to the capabilities offered by the telescope hardware subsystems for testing and maintenance. Leveraging these generated libraries and components we then implemented a human designed, integrated, Engineering GUI for MASS to perform the verification of the whole prototype and test shared services such as the alarms, configurations, control systems, and scientific on-line outcomes. In our experience the use of code generation dramatically reduced the amount of effort in development, integration and testing of the more basic software components and resulted in a fast software release life cycle. This approach could be valuable for the whole CTA project, characterized by a large diversity of hardware components.

Discarded solar array panel removed from Hubble Space telescope

NASA Image and Video Library

1993-12-06

STS061-95-031 (6 Dec 1993) --- The damaged solar array panel removed from the Hubble Space Telescope (HST) is backdropped over northern Sudan. Astronaut Kathryn C. Thornton, just out of frame at top right, watched the panel after releasing it moments earlier.

Towards a flexible array control and operation framework for CTA

NASA Astrophysics Data System (ADS)

Birsin, E.; Colomé, J.; Hoffmann, D.; Koeppel, H.; Lamanna, G.; Le Flour, T.; Lopatin, A.; Lyard, E.; Melkumyan, D.; Oya, I.; Panazol, J.-L.; Schlenstedt, S.; Schmidt, T.; Schwanke, U.; Stegmann, C.; Walter, R.; Wegner, P.; CTA Consortium

2012-12-01

The Cherenkov Telescope Array (CTA) [1] will be the successor to current Imaging Atmospheric Cherenkov Telescopes (IACT) like H.E.S.S., MAGIC and VERITAS. CTA will improve in sensitivity by about an order of magnitude compared to the current generation of IACTs. The energy range will extend from well below 100 GeV to above 100 TeV. To accomplish these goals, CTA will consist of two arrays, one in each hemisphere, consisting of 50-80 telescopes and composed of three different telescope types with different mirror sizes. It will be the first open observatory for very high energy γ-ray astronomy. The Array Control working group of CTA is currently evaluating existing technologies which are best suited for a project like CTA. The considered solutions comprise the ALMA Common Software (ACS), the OPC Unified Architecture (OPC UA) and the Data Distribution Service (DDS) for bulk data transfer. The first applications, like an automatic observation scheduler and the control software for some prototype instrumentation have been developed.

Next-generation Event Horizon Telescope developments: new stations for enhanced imaging

NASA Astrophysics Data System (ADS)

Palumbo, Daniel; Johnson, Michael; Doeleman, Sheperd; Chael, Andrew; Bouman, Katherine

2018-01-01

The Event Horizon Telescope (EHT) is a multinational Very Long Baseline Interferometry (VLBI) network of dishes joined to resolve general relativistic behavior near a supermassive black hole. The imaging quality of the EHT is largely dependent upon the sensitivity and spatial frequency coverage of the many baselines between its constituent telescopes. The EHT already contains many highly sensitive dishes, including the crucial Atacama Large Millimeter/Submillimeter Array (ALMA), making it viable to add smaller, cheaper telescopes to the array, greatly improving future capabilities of the EHT. We develop tools for optimizing the positions of new dishes in planned arrays. We also explore the feasibility of adding small orbiting dishes to the EHT, and develop orbital optimization tools for space-based VLBI imaging. Unlike the Millimetron mission planned to be at L2, we specifically treat near-earth orbiters, and find rapid filling of spatial frequency coverage across a large range of baseline lengths. Finally, we demonstrate significant improvement in image quality when adding small dishes to planned arrays in simulated observations.

SKA aperture array verification system: electromagnetic modeling and beam pattern measurements using a micro UAV

NASA Astrophysics Data System (ADS)

de Lera Acedo, E.; Bolli, P.; Paonessa, F.; Virone, G.; Colin-Beltran, E.; Razavi-Ghods, N.; Aicardi, I.; Lingua, A.; Maschio, P.; Monari, J.; Naldi, G.; Piras, M.; Pupillo, G.

2018-03-01

In this paper we present the electromagnetic modeling and beam pattern measurements of a 16-elements ultra wideband sparse random test array for the low frequency instrument of the Square Kilometer Array telescope. We discuss the importance of a small array test platform for the development of technologies and techniques towards the final telescope, highlighting the most relevant aspects of its design. We also describe the electromagnetic simulations and modeling work as well as the embedded-element and array pattern measurements using an Unmanned Aerial Vehicle system. The latter are helpful both for the validation of the models and the design as well as for the future instrumental calibration of the telescope thanks to the stable, accurate and strong radio frequency signal transmitted by the UAV. At this stage of the design, these measurements have shown a general agreement between experimental results and numerical data and have revealed the localized effect of un-calibrated cable lengths in the inner side-lobes of the array pattern.

The control system of the 12-m medium-size telescope prototype: a test-ground for the CTA array control

NASA Astrophysics Data System (ADS)

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

2014-07-01

The Cherenkov Telescope Array (CTA) will be the next generation ground-based very-high energy -ray observatory. 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 sizes and types and in addition numerous auxiliary devices. In order to provide a test-ground for the CTA array control, the steering software of the 12-m medium size telescope (MST) prototype deployed in Berlin has been implemented using the tools and design concepts under consideration to be used for the control of the CTA array. The prototype control system is implemented based on the Atacama Large Millimeter/submillimeter Array (ALMA) Common Software (ACS) control middleware, with components implemented in Java, C++ and Python. The interfacing to the hardware is standardized via the Object Linking and Embedding for Process Control Unified Architecture (OPC UA). In order to access the OPC UA servers from the ACS framework in a common way, a library has been developed that allows to tie the OPC UA server nodes, methods and events to the equivalents in ACS components. The front-end of the archive system is able to identify the deployed components and to perform the sampling of the monitoring points of each component following time and value change triggers according to the selected configurations. The back-end of the archive system of the prototype is composed by two different databases: MySQL and MongoDB. MySQL has been selected as storage of the system configurations, while MongoDB is used to have an efficient storage of device monitoring data, CCD images, logging and alarm information. In this contribution, the details and conclusions on the implementation of the control software of the MST prototype are presented.

The Advanced Gamma-ray Imaging System (AGIS): Topological Array Trigger

NASA Astrophysics Data System (ADS)

Smith, Andrew W.

2010-03-01

AGIS is a concept for the next-generation ground-based gamma-ray observatory. It will be an array of 36 imaging atmospheric Cherenkov telescopes (IACTs) sensitive in the energy range from 50 GeV to 200 TeV. The required improvements in sensitivity, angular resolution, and reliability of operation relative to the present generation instruments imposes demanding technological and cost requirements on the design of the telescopes and on the triggering and readout systems for AGIS. To maximize the capabilities of large arrays of IACTs with a low energy threshold, a wide field of view and a low background rate, a sophisticated array trigger is required. We outline the status of the development of a stereoscopic array trigger that calculates image parameters and correlates them across a subset of telescopes. Field Programmable Gate Arrays (FPGAs) implement the real-time pattern recognition to suppress cosmic rays and night-sky background events. A proof of principle system is being developed to run at camera trigger rates up to 10MHz and array-level rates up to 10kHz.

Hubble refurbished and ready for release

NASA Astrophysics Data System (ADS)

1993-12-01

The deployment of the solar arrays came at the end of the fifth and final spacewalk of the mission. Story Musgrave and Jeff Hoffman spent seven-hours in the cargo bay fitting new electrical systems and installing covers over the telescope's old magnetometers. The first task was the installation of "SADE", a new ESA- supplied Solar Array Drive Electronics box. The box directs the twin solar panels at the Sun. The astronauts then lent a helping hand to lower the masts holding the solar arrays to their deployment position. Flight controllers decided to crank the masts out manually because of minor trouble with the latches. The next job was the installation of the Goddard High Resolution Spectrograph (GHRS) Redundancy Kit, a device that provides an alternate power and data route for the instrument. The ESA supplied solar blankets rolled off their canisters without incident between 4 and 4h35 a.m. CST (11 and 11h35 a.m. CET). An hour later the new SADE system turned the arrays towards the sun. "It is a tribute to the whole team, from the designers to the astronauts, that everything has gone so well", said Derek Eaton, ESA's HST project manager. "I only hope that the array will look so good when the shuttle returns to the telescope in 1997". The telescope's first set of solar arrays flexed in orbit because of the sudden swing in temperature as the telescope moved in and out of sunlight. The movement, known as jitter, affected the telescope's pointing system and disrupted observations at certain times. Special software compensated largely for the problem but this occupied a large amount of computer memory. The design of the new arrays was modified to eliminate the problem. Eaton said he was "101 per cent" confident that jitter from the arrays would no longer affect the work of the telescope. The deployment of the power-generating wings brought the servicing work to a close. If all goes according to plan, the telescope will return to orbital at 1.08 a.m. CST (8.08 a.m. CET) tomorrow morning. The telescope's aperture door will open just prior to the release. ESA astronaut Claude Nicollier will operate the shuttle's robot arm during the deployment, as he has throughout the lengthy spacewalks and the retrieval of the telescope. This mission has seen more arm operations than any other. Milt Heflin, NASA's lead flight director for the mission, paid tribute to Nicollier at a news conference today. "Claude was magnificent arm driver" he said. "The arm was surgically put in place every time. Folks can be very proud of him". Endeavour is scheduled to return to Earth Monday 13 December.

First upper limits on the radar cross section of cosmic-ray induced extensive air showers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbasi, R. U.; Abe, M.; Abou Bakr Othman, M.

TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. Furthermore, the TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in durationmore » (~10 µs) and exhibit rapidly changing frequency, with rates on the order 1 MHz/µs. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. One novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. Finally, we report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector.« less

First upper limits on the radar cross section of cosmic-ray induced extensive air showers

DOE PAGES

Abbasi, R. U.; Abe, M.; Abou Bakr Othman, M.; ...

2016-11-19

TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. Furthermore, the TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in durationmore » (~10 µs) and exhibit rapidly changing frequency, with rates on the order 1 MHz/µs. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. One novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. Finally, we report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector.« less

The control, monitor, and alarm system for the ICT equipment of the ASTRI SST-2M telescope prototype for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Gianotti, Fulvio; Fioretti, Valentina; Tanci, Claudio; Conforti, Vito; Tacchini, Alessandro; Leto, Giuseppe; Gallozzi, Stefano; Bulgarelli, Andrea; Trifoglio, Massimo; Malaguti, Giuseppe; Zoli, Andrea

2014-07-01

ASTRI is an Italian flagship project whose first goal is the realization of an end-to-end telescope prototype, named ASTRI SST-2M, for the Cherenkov Telescope Array (CTA). The prototype will be installed in Italy during Fall 2014. A second goal will be the realization of the ASTRI/CTA mini-array which will be composed of seven SST-2M telescopes placed at the CTA Southern Site. The Information and Communication Technology (ICT) equipment necessary to drive the infrastructure for the ASTRI SST-2M prototype is being designed as a complete and stand-alone computer center. The design goal is to obtain basic ICT equipment that might be scaled, with a low level of redundancy, for the ASTRI/CTA mini-array, taking into account the necessary control, monitor and alarm system requirements. The ICT equipment envisaged at the Serra La Nave observing station in Italy, where the ASTRI SST-2M telescope prototype will operate, includes computers, servers and workstations, network devices, an uninterruptable power supply system, and air conditioning systems. Suitable hardware and software tools will allow the parameters related to the behavior and health of each item of equipment to be controlled and monitored. This paper presents the proposed architecture and technical solutions that integrate the ICT equipment in the framework of the Observatory Control System package of the ASTRI/CTA Mini- Array Software System, MASS, to allow their local and remote control and monitoring. An end-toend test case using an Internet Protocol thermometer is reported in detail.

The SKA1 LOW telescope: system architecture and design performance

NASA Astrophysics Data System (ADS)

Waterson, Mark F.; Labate, Maria Grazia; Schnetler, Hermine; Wagg, Jeff; Turner, Wallace; Dewdney, Peter

2016-07-01

The SKA1-LOW radio telescope will be a low-frequency (50-350 MHz) aperture array located in Western Australia. Its scientific objectives will prioritize studies of the Epoch of Reionization and pulsar physics. Development of the telescope has been allocated to consortia responsible for the aperture array front end, timing distribution, signal and data transport, correlation and beamforming signal processors, infrastructure, monitor and control systems, and science data processing. This paper will describe the system architectural design and key performance parameters of the telescope and summarize the high-level sub-system designs of the consortia.

The software system for the Control and Data Acquisition for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Wegner, P.; FüBling, M.; Oya, I.; Hagge, L.; Schwanke, U.; Schwarz, J.; Tosti, G.; Conforti, V.; Lyard, E.; Walter, R.; Oliveira Antonino, P.; Morgenstern, A.

2016-10-01

The Cherenkov Telescope Array (CTA), as the next generation ground-based very high-energy gamma-ray observatory, is defining new areas beyond those related to physics. It is also creating new demands on the control and data acquisition system. CTA will consist of two installations, one in each hemisphere, containing tens of telescopes of different sizes. The ACTL (array control and data acquisition) system will consist of the hardware and software that is necessary to control and monitor the CTA array, as well as to time-stamp, read-out, filter and store the scientific data at aggregated rates of a few GB/s. The ACTL system must implement a flexible software architecture to permit the simultaneous automatic operation of multiple sub-arrays of telescopes with a minimum personnel effort on site. In addition ACTL must be able to modify the observation schedule on timescales of a few tens of seconds, to account for changing environmental conditions or to prioritize incoming scientific alerts from time-critical transient phenomena such as gamma-ray bursts. This contribution summarizes the status of the development of the software architecture and the main design choices and plans.

Hubble Space Telescope Bi-Stem Thermal Shield Analyses

NASA Technical Reports Server (NTRS)

Finlay, Katherine A.

2004-01-01

The Hubble Space Telescope (HST) was launched April 24, 1990, and was deployed April 25 into low Earth orbit (LEO). It was soon discovered that the metal poles holding the solar arrays were expanding and contracting as the telescope orbited the Earth passing between the sunlight and the Earth s shadow. The expansion and contraction, although very small, was enough to cause the telescope to shake because of thermal-induced jitters, a detrimental effect when trying to take pictures millions of miles away. Therefore, the European Space Agency (ESA, the provider of the solar arrays) built new solar arrays (SA-11) that contained bi-stem thermal shields which insulated the solar array metal poles. These thermal shields were made of 2 mil thick aluminized-Teflon fluorinated ethylene propylene (FEP) rings fused together into a circular bellows shape. The new solar arrays were put on the HST during an extravehicular activity (EVA), also called an astronaut space walk, during the first servicing mission (SM1) in December 1993. An on-orbit photograph of the HST with the SA-11, and a close up of the bellows-like structure of the thermal shields is provided in Figure 1.

The IceCube Neutrino Observatory, the Pierre Auger Observatory and the Telescope Array: Joint Contribution to the 35th International Cosmic Ray Conference (ICRC 2017)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aartsen, M. G.; et al.

Joint contributions of the IceCube Collaboration, the Telescope Array Collaboration, and the Pierre Auger Collaboration to the 35th International Cosmic Ray Conference (ICRC 2017), 12-20 July 2017, Bexco, Busan, Korea.

Constraining dust properties in circumstellar envelopes of C-stars in the Small Magellanic Cloud: optical constants and grain size of carbon dust

NASA Astrophysics Data System (ADS)

Nanni, Ambra; Marigo, Paola; Groenewegen, Martin A. T.; Aringer, Bernhard; Girardi, Léo; Pastorelli, Giada; Bressan, Alessandro; Bladh, Sara

2016-10-01

We present a new approach aimed at constraining the typical size and optical properties of carbon dust grains in circumstellar envelopes (CSEs) of carbon-rich stars (C-stars) in the Small Magellanic Cloud (SMC). To achieve this goal, we apply our recent dust growth description, coupled with a radiative transfer code to the CSEs of C-stars evolving along the thermally pulsing asymptotic giant branch, for which we compute spectra and colours. Then, we compare our modelled colours in the near- and mid-infrared (NIR and MIR) bands with the observed ones, testing different assumptions in our dust scheme and employing several data sets of optical constants for carbon dust available in the literature. Different assumptions adopted in our dust scheme change the typical size of the carbon grains produced. We constrain carbon dust properties by selecting the combination of grain size and optical constants which best reproduce several colours in the NIR and MIR at the same time. The different choices of optical properties and grain size lead to differences in the NIR and MIR colours greater than 2 mag in some cases. We conclude that the complete set of observed NIR and MIR colours are best reproduced by small grains, with sizes between ˜0.035 and ˜0.12 μm, rather than by large grains between ˜0.2 and 0.7 μm. The inability of large grains to reproduce NIR and MIR colours seems independent of the adopted optical data set. We also find a possible trend of the grain size with mass-loss and/or carbon excess in the CSEs of these stars.

Constraining Dust Properties in Circumstellar Envelopes of C-Stars in the Small Magellanic Cloud: Optical Constants And Grain Size Of Carbon Dust

NASA Astrophysics Data System (ADS)

Nanni, Ambra; Marigo, Paola; Groenewegen, Martin A. T.; Aringer, Berhard; Girardi, Léo; Pastorelli, Giada; Bressan, Alessandro; Bladh, Sara

2016-07-01

We present our recent investigation aimed at constraining the typical size and optical properties of carbon dust grains in Circumstellar envelopes (CSEs) of carbon-rich stars (C-stars) in the Small Magellanic Cloud (SMC).We applied our recent dust growth model, coupled with a radiative transfer code, to the dusty CSEs of C-stars along the TP-AGB phase, for which we computed spectra and colors. We then compared our modeled colors in the Near and Mid Infrared (NIR and MIR) bands with the observed ones, testing different assumptions in our dust scheme and employing different optical constants data sets for carbon dust. We constrained the optical properties of carbon dust by identifying the combinations of typical grain size and optical constants data set which simultaneously reproduce several colors in the NIR and MIR wavelengths. In particular, the different choices of optical properties and grain size lead to differences in the NIR and MIR colors greater than two magnitudes in some cases. We concluded that the complete set of selected NIR and MIR colors are best reproduced by small grains, with sizes between 0.06 and 0.1 mum, rather than by large grains of 0.2-0.4 mum. The inability of large grains to reproduce NIR and MIR colors is found to be independent of the adopted optical data set and the deviations between models and observations tend to increase for increasing grain sizes. We also find a possible trend of the typical grain size with mss-loss and/or carbon-excess in the CSEs of these stars.The work presented is preparatory to future studies aimed at calibrating the TP-AGB phase through resolved stellar populations in the framework of the STARKEY project.

Chinese lupus treatment and research group (CSTAR) registry: X. family history in relation to lupus clinical and immunological manifestations.

PubMed

Leng, Xiaomei; Li, Mengtao; Li, Xiangpei; Zhang, Xiao; Liu, Shengyun; Wu, Lijun; Ma, Li; Bi, Liqi; Zuo, Xiaoxia; Sun, Lingyun; Huang, Cibo; Zhao, Jiuliang; Zhao, Yan; Zeng, Xiaofeng

2018-01-01

This study aimed to examine the associations between family history and clinical manifestations and immunologic characteristics of lupus in China. Based on their family history, lupus patients from the Chinese lupus treatment and research group (CSTAR) registry were categorised: familial lupus (FL), family history of other rheumatic disorders (RD), and sporadic lupus (SL). Demographic data, clinical manifestations, and laboratory data were compared among these three groups. A total of 2,104 patients from CSTAR were included, with 34 (1.6%) in the FL group, 50 (2.4%) in the RD group, and 2,020 (96.0%) in the SL group. There were no significant differences in age or gender among these groups (p=0.36 and p=0.75, respectively). The prevalence of discoid rash and positivity of anti-RNP antibodies differed significantly among the three groups. Photosensitivity and neurological disorder were marginally significantly different among the three groups (p=0.05). No statistical differences were observed in other clinical manifestations or laboratory results. In the FL group, first-degree relatives (25/34, 73.5%) had higher susceptibility to lupus. Rheumatoid arthritis (RA) (35/50, 70.0%) was the most frequent non-lupus rheumatic disorder in the RD group. Among lupus patients, the rate of familial lupus was lower in Chinese patients than among other ethnicities. Familial lupus cases are found mainly among their first-degree relatives. A family history of lupus did not significantly affect clinical phenotypes, except for higher frequency of discoid rash and anti-RNP in the FL group, and more anti-RNP positivity in the RD group.

Simultaneous operation and control of about 100 telescopes for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Wegner, P.; Colomé, J.; Hoffmann, D.; Houles, J.; Köppel, H.; Lamanna, G.; Le Flour, T.; Lopatin, A.; Lyard, E.; Melkumyan, D.; Oya, I.; Panazol, L.-I.; Punch, M.; Schlenstedt, S.; Schmidt, T.; Stegmann, C.; Schwanke, U.; Walter, R.; Consortium, CTA

2012-12-01

The Cherenkov Telescope Array (CTA) project is an initiative to build the next generation ground-based very high energy (VHE) gamma-ray instrument. Compared to current imaging atmospheric Cherenkov telescope experiments CTA will extend the energy range and improve the angular resolution while increasing the sensitivity up to a factor of 10. With about 100 separate telescopes it will be operated as an observatory open to a wide astrophysics and particle physics community, providing a deep insight into the non-thermal high-energy universe. The CTA Array Control system (ACTL) is responsible for several essential control tasks supporting the evaluation and selection of proposals, as well as the preparation, scheduling, and finally the execution of observations with the array. A possible basic distributed software framework for ACTL being considered is the ALMA Common Software (ACS). The ACS framework follows a container component model and contains a high level abstraction layer to integrate different types of device. To achieve a low-level consolidation of connecting control hardware, OPC UA (OPen Connectivity-Unified Architecture) client functionality is integrated directly into ACS, thus allowing interaction with other OPC UA capable hardware. The CTA Data Acquisition System comprises the data readout of all cameras and the transfer of the data to a camera server farm, thereby using standard hardware and software technologies. CTA array control is also covering conceptions for a possible array trigger system and the corresponding clock distribution. The design of the CTA observations scheduler is introducing new algorithmic technologies to achieve the required flexibility.

The Cherenkov Telescope Array production system for Monte Carlo simulations and analysis

NASA Astrophysics Data System (ADS)

Arrabito, L.; Bernloehr, K.; Bregeon, J.; Cumani, P.; Hassan, T.; Haupt, A.; Maier, G.; Moralejo, A.; Neyroud, N.; pre="for the"> CTA Consortium, DIRAC Consortium,

2017-10-01

The Cherenkov Telescope Array (CTA), an array of many tens of Imaging Atmospheric Cherenkov Telescopes deployed on an unprecedented scale, is the next-generation instrument in the field of very high energy gamma-ray astronomy. An average data stream of about 0.9 GB/s for about 1300 hours of observation per year is expected, therefore resulting in 4 PB of raw data per year and a total of 27 PB/year, including archive and data processing. The start of CTA operation is foreseen in 2018 and it will last about 30 years. The installation of the first telescopes in the two selected locations (Paranal, Chile and La Palma, Spain) will start in 2017. In order to select the best site candidate to host CTA telescopes (in the Northern and in the Southern hemispheres), massive Monte Carlo simulations have been performed since 2012. Once the two sites have been selected, we have started new Monte Carlo simulations to determine the optimal array layout with respect to the obtained sensitivity. Taking into account that CTA may be finally composed of 7 different telescope types coming in 3 different sizes, many different combinations of telescope position and multiplicity as a function of the telescope type have been proposed. This last Monte Carlo campaign represented a huge computational effort, since several hundreds of telescope positions have been simulated, while for future instrument response function simulations, only the operating telescopes will be considered. In particular, during the last 18 months, about 2 PB of Monte Carlo data have been produced and processed with different analysis chains, with a corresponding overall CPU consumption of about 125 M HS06 hours. In these proceedings, we describe the employed computing model, based on the use of grid resources, as well as the production system setup, which relies on the DIRAC interware. Finally, we present the envisaged evolutions of the CTA production system for the off-line data processing during CTA operations and the instrument response function simulations.

Feasibility of utilizing Cherenkov Telescope Array gamma-ray telescopes as free-space optical communication ground stations.

PubMed

Carrasco-Casado, Alberto; Vilera, Mariafernanda; Vergaz, Ricardo; Cabrero, Juan Francisco

2013-04-10

The signals that will be received on Earth from deep-space probes in future implementations of free-space optical communication will be extremely weak, and new ground stations will have to be developed in order to support these links. This paper addresses the feasibility of using the technology developed in the gamma-ray telescopes that will make up the Cherenkov Telescope Array (CTA) observatory in the implementation of a new kind of ground station. Among the main advantages that these telescopes provide are the much larger apertures needed to overcome the power limitation that ground-based gamma-ray astronomy and optical communication both have. Also, the large number of big telescopes that will be built for CTA will make it possible to reduce costs by economy-scale production, enabling optical communications in the large telescopes that will be needed for future deep-space links.

University of Tennessee Center for Space Transportation and Applied Research (CSTAR)

NASA Astrophysics Data System (ADS)

1995-10-01

The Center for Space Transportation and Applied Research had projects with space applications in six major areas: laser materials processing, artificial intelligence/expert systems, space transportation, computational methods, chemical propulsion, and electric propulsion. The closeout status of all these projects is addressed.

University of Tennessee Center for Space Transportation and Applied Research (CSTAR)

NASA Technical Reports Server (NTRS)

1995-01-01

The Center for Space Transportation and Applied Research had projects with space applications in six major areas: laser materials processing, artificial intelligence/expert systems, space transportation, computational methods, chemical propulsion, and electric propulsion. The closeout status of all these projects is addressed.

Prospects for PWNe and SNRs science with the ASTRI mini-array of pre-production small-sized telescopes of the Cherenkov telescope array

NASA Astrophysics Data System (ADS)

Burtovoi, A.; Zampieri, L.; Giuliani, A.; Bigongiari, C.; Di Pierro, F.; Stamerra, A.

2017-01-01

The development and construction of the Cherenkov Telescope Array (CTA) opens up new opportunities for the study of very high energy (VHE, E > 100 GeV) sources. As a part of CTA, the ASTRI project, led by INAF, has one of the main goals to develop one of the mini-arrays of CTA pre-production telescopes, proposed to be installed at the CTA southern site. Thanks to the innovative dual-mirror optical design of its small-sized telescopes, the ASTRI mini-array will be characterized by a large field of view, an excellent angular resolution and a good sensitivity up to energies of several tens of TeV. Pulsar wind nebulae, along with Supernova Remnants, are among the most abundant sources that will be identified and investigated, with the ultimate goal to move significantly closer to an understanding of the origin of cosmic rays (CR). As part of the ongoing effort to investigate the scientific capabilities for both CTA as a whole and the ASTRI mini-array, we performed simulations of the Vela X region. We simulated its extended VHE γ-ray emission using the results of the detailed H.E.S.S. analysis of this source. We estimated the resolving capabilities of the diffuse emission and the detection significance of the pulsar with both CTA as a whole and the ASTRI mini-array. Moreover with these instruments it will be possible to observe the high-energy end of SNRs spectrum, searching for particles with energies near the cosmic-rays "knee" (E ˜ 1015 eV). We simulated a set of ASTRI mini-array observations for one young and an evolved SNRs in order to test the capabilities of this instrument to discover and study PeVatrons on the Galactic plane.

Superconductor lunar telescopes --Abstract only

NASA Technical Reports Server (NTRS)

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

1994-01-01

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

Rearranging the lenslet array of the compact passive interference imaging system with high resolution

NASA Astrophysics Data System (ADS)

Liu, Gang; Wen, Desheng; Song, Zongxi

2017-10-01

With the development of aeronautics and astronautics, higher resolution requirement of the telescope was necessary. However, the increase in resolution of conventional telescope required larger apertures, whose size, weight and power consumption could be prohibitively expensive. This limited the further development of the telescope. This paper introduced a new imaging technology using interference—Compact Passive Interference Imaging Technology with High Resolution, and proposed a rearranging method for the arrangement of the lenslet array to obtain continuously object spatial frequency.

Superconductor lunar telescopes --Abstract only

NASA Astrophysics Data System (ADS)

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

1994-06-01

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

Adaptive optics for array telescopes using piston-and-tilt wave-front sensing

NASA Technical Reports Server (NTRS)

Wizinowich, P.; Mcleod, B.; Lloyd-Yhart, M.; Angel, J. R. P.; Colucci, D.; Dekany, R.; Mccarthy, D.; Wittman, D.; Scott-Fleming, I.

1992-01-01

A near-infrared adaptive optics system operating at about 50 Hz has been used to control phase errors adaptively between two mirrors of the Multiple Mirror Telescope by stabilizing the position of the interference fringe in the combined unresolved far-field image. The resultant integrated images have angular resolutions of better than 0.1 arcsec and fringe contrasts of more than 0.6. Measurements of wave-front tilt have confirmed the wavelength independence of image motion. These results show that interferometric sensing of phase errors, when combined with a system for sensing the wave-front tilt of the individual telescopes, will provide a means of achieving a stable diffraction-limited focus with segmented telescopes or arrays of telescopes.

Diffraction-limited imaging with very large telescopes; Proceedings of the NATO Advanced Study Institute, Cargese, France, Sept. 13-23, 1988

NASA Astrophysics Data System (ADS)

Alloin, D. M.; Mariotti, J.-M.

Recent advances in optics and observation techniques for very large astronomical telescopes are discussed in reviews and reports. Topics addressed include Fourier optics and coherence, optical propagation and image formation through a turbulent atmosphere, radio telescopes, continuously deformable telescopes for optical interferometry (I), amplitude estimation from speckle I, noise calibration of speckle imagery, and amplitude estimation from diluted-array I. Consideration is given to first-order imaging methods, speckle imaging with the PAPA detector and the Knox-Thompson algorithm, phase-closure imaging, real-time wavefront sensing and adaptive optics, differential I, astrophysical programs for high-angular-resolution optical I, cophasing telescope arrays, aperture synthesis for space observatories, and lunar occultations for marcsec resolution.

NectarCAM, a camera for the medium sized telescopes of the Cherenkov telescope array

NASA Astrophysics Data System (ADS)

Glicenstein, J.-F.; Shayduk, M.

2017-01-01

NectarCAM is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA) which covers the core energy range of 100 GeV to 30 TeV. It has a modular design and is based on the NECTAr chip, at the heart of which is a GHz sampling Switched Capacitor Array and 12-bit Analog to Digital converter. The camera will be equipped with 265 7-photomultiplier modules, covering a field of view of 8 degrees. Each module includes photomultiplier bases, high voltage supply, pre-amplifier, trigger, readout and Ethernet transceiver. The recorded events last between a few nanoseconds and tens of nanoseconds. The expected performance of the camera are discussed. Prototypes of NectarCAM components have been built to validate the design. Preliminary results of a 19-module mini-camera are presented, as well as future plans for building and testing a full size camera.

Multinode data acquisition and control system for the 4-element TACTIC telescope array

NASA Astrophysics Data System (ADS)

Yadav, K. K.; Chouhan, N.; Kaul, S. R.; Koul, R.

2002-03-01

An interrupt driven multinode data acquisition and control system has been developed for the 4-element gamma-ray telescope array, TACTIC. Computer networking technology and the CAMAC bus have been integrated to develop this icon-based, userfriendly failsafe system. The paper describes the salient features of the system.

Observatories Combine to Crack Open the Crab Nebula

NASA Image and Video Library

2017-12-08

Astronomers have produced a highly detailed image of the Crab Nebula, by combining data from telescopes spanning nearly the entire breadth of the electromagnetic spectrum, from radio waves seen by the Karl G. Jansky Very Large Array (VLA) to the powerful X-ray glow as seen by the orbiting Chandra X-ray Observatory. And, in between that range of wavelengths, the Hubble Space Telescope's crisp visible-light view, and the infrared perspective of the Spitzer Space Telescope. This composite image of the Crab Nebula, a supernova remnant, was assembled by combining data from five telescopes spanning nearly the entire breadth of the electromagnetic spectrum: the Very Large Array, the Spitzer Space Telescope, the Hubble Space Telescope, the XMM-Newton Observatory, and the Chandra X-ray Observatory. Credits: NASA, ESA, NRAO/AUI/NSF and G. Dubner (University of Buenos Aires) #nasagoddard #space #science

Computer-generated scenes depicting the HST capture and EVA repair mission

NASA Image and Video Library

1993-11-12

Computer generated scenes depicting the Hubble Space Telescope capture and a sequence of planned events on the planned extravehicular activity (EVA). Scenes include the Remote Manipulator System (RMS) arm assisting two astronauts changing out the Wide Field/Planetary Camera (WF/PC) (48699); RMS arm assisting in the temporary mating of the orbiting telescope to the flight support system in Endeavour's cargo bay (48700); Endeavour's RMS arm assisting in the "capture" of the orbiting telescope (48701); Two astronauts changing out the telescope's coprocessor (48702); RMS arm assistign two astronauts replacing one of the telescope's electronic control units (48703); RMS assisting two astronauts replacing the fuse plugs on the telescope's Power Distribution Unit (PDU) (48704); The telescope's High Resolution Spectrograph (HRS) kit is depicted in this scene (48705); Two astronauts during the removal of the high speed photometer and the installation of the COSTAR instrument (48706); Two astronauts, standing on the RMS, during installation of one of the Magnetic Sensing System (MSS) (48707); High angle view of the orbiting Space Shuttle Endeavour with its cargo bay doors open, revealing the bay's pre-capture configuration. Seen are, from the left, the Solar Array Carrier, the ORU Carrier and the flight support system (48708); Two astronauts performing the replacement of HST's Rate Sensor Units (RSU) (48709); The RMS arm assisting two astronauts with the replacement of the telescope's solar array panels (48710); Two astronauts replacing the telescope's Solar Array Drive Electronics (SADE) (48711).

Wide-Angle, Flat-Field Telescope

NASA Technical Reports Server (NTRS)

Hallam, K. L.; Howell, B. J.; Wilson, M. E.

1987-01-01

All-reflective system unvignetted. Wide-angle telescope uses unobstructed reflecting elements to produce flat image. No refracting elements, no chromatic aberration, and telescope operates over spectral range from infrared to far ultraviolet. Telescope used with such image detectors as photographic firm, vidicons, and solid-state image arrays.

The High-Level Interface Definitions in the ASTRI/CTA Mini Array Software System (MASS)

NASA Astrophysics Data System (ADS)

Conforti, V.; Tosti, G.; Schwarz, J.; Bruno, P.; Cefal‘A, M.; Paola, A. D.; Gianotti, F.; Grillo, A.; Russo, F.; Tanci, C.; Testa, V.; Antonelli, L. A.; Canestrari, R.; Catalano, O.; Fiorini, M.; Gallozzi, S.; Giro, E.; Palombara, N. L.; Leto, G.; Maccarone, M. C.; Pareschi, G.; Stringhetti, L.; Trifoglio, M.; Vercellone, S.; Astri Collaboration; Cta Consortium

2015-09-01

ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project funded by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. Within this framework, INAF is currently developing an end-to-end prototype, named ASTRI SST-2M, of a Small Size Dual-Mirror Telescope for the Cherenkov Telescope Array, CTA. A second goal of the project is the realization of the ASTRI/CTA mini-array, which will be composed of seven SST-2M telescopes placed at the CTA Southern Site. The ASTRI Mini Array Software System (MASS) is designed to support the ASTRI/CTA mini-array operations. MASS is being built on top of the ALMA Common Software (ACS) framework, which provides support for the implementation of distributed data acquisition and control systems, and functionality for log and alarm management, message driven communication and hardware devices management. The first version of the MASS system, which will comply with the CTA requirements and guidelines, will be tested on the ASTRI SST-2M prototype. In this contribution we present the interface definitions of the MASS high level components in charge of the ASTRI SST-2M observation scheduling, telescope control and monitoring, and data taking. Particular emphasis is given to their potential reuse for the ASTRI/CTA mini-array.

Prototyping the graphical user interface for the operator of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Sadeh, I.; Oya, I.; Schwarz, J.; Pietriga, E.

2016-07-01

The Cherenkov Telescope Array (CTA) is a planned gamma-ray observatory. CTA will incorporate about 100 imaging atmospheric Cherenkov telescopes (IACTs) at a Southern site, and about 20 in the North. Previous IACT experiments have used up to five telescopes. Subsequently, the design of a graphical user interface (GUI) for the operator of CTA involves new challenges. We present a GUI prototype, the concept for which is being developed in collaboration with experts from the field of Human-Computer Interaction (HCI). The prototype is based on Web technology; it incorporates a Python web server, Web Sockets and graphics generated with the d3.js Javascript library.

SiPM detectors for the ASTRI project in the framework of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Billotta, Sergio; Marano, Davide; Bonanno, Giovanni; Belluso, Massimiliano; Grillo, Alessandro; Garozzo, Salvatore; Romeo, Giuseppe; Timpanaro, Maria Cristina; Maccarone, Maria Concetta C.; Catalano, Osvaldo; La Rosa, Giovanni; Sottile, Giuseppe; Impiombato, Domenico; Gargano, Carmelo; Giarrusso, Salavtore

2014-07-01

The Cherenkov Telescope Array (CTA) is a worldwide new generation project aimed at realizing an array of a hundred ground based gamma-ray telescopes. ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is the Italian project whose primary target is the development of an end-to-end prototype, named ASTRI SST-2M, of the CTA small size class of telescopes devoted to investigation of the highest energy region, from 1 to 100 TeV. Next target is the implementation of an ASTRI/CTA mini-array based on seven identical telescopes. Silicon Photo-Multipliers (SiPMs) are the semiconductor photosensor devices designated to constitute the camera detection system at the focal plane of the ASTRI telescopes. SiPM photosensors are suitable for the detection of the Cherenkov flashes, since they are very fast and sensitive to the light in the 300-700nm wavelength spectrum. Their drawbacks compared to the traditional photomultiplier tubes are high dark count rates, after-pulsing and optical cross-talk contributions, and intrinsic gains strongly dependent on temperature. Nonetheless, for a single pixel, the dark count rate is well below the Night Sky Background, the effects of cross-talk and afterpulses are typically lower than 20%, and the gain can be kept stable against temperature variations by means of adequate bias voltage compensation strategies. This work presents and discusses some experimental results from a large set of measurements performed on the SiPM sensors to be used for the ASTRI SST-2M prototype camera and on recently developed detectors demonstrating outstanding performance for the future evolution of the project in the ASTRI/CTA mini-array.

Phase Synchronization for the Mid-Frequency Square Kilometre Array Telescope

NASA Astrophysics Data System (ADS)

Schediwy, Sascha; Gozzard, David; Stobie, Simon; Gravestock, Charles; Whitaker, Richard; Alachkar, Bassem; Malan, Sias; Boven, Paul; Grainge, Keith

2018-01-01

The Square Kilometre Array (SKA) project is an international effort to build the world’s most sensitive radio telescope operating in the 50 MHz to 14 GHz frequency range. Construction of the SKA has been divided into phases, with the first phase (SKA1) accounting for the first 10% of the telescope's receiving capacity. During SKA1, a low-frequency aperture array comprising over a hundred thousand individual dipole antenna elements will be constructed in Western Australia (SKA1-low), while an array of 197 parabolic-dish antennas, incorporating the 64 dishes of MeerKAT, will be constructed in South Africa (SKA1-mid).Radio telescope arrays such as the SKA require phase-coherent reference signals to be transmitted to each antenna site in the array. In the case of the SKA1-mid, these reference signals will be generated at a central site and transmitted to the antenna sites via fiber-optic cables up to 175 km in length. Environmental perturbations affect the optical path length of the fiber and act to degrade the phase stability of the reference signals received at the antennas, which has the ultimate effect of reducing the fidelity and dynamic range of the data.Since 2011, researchers at the University of Western Australia (UWA) have led the development of an actively-stabilized phase-synchronization system designed specifically to meet the scientific needs and technical challenges of the SKA telescope. Recently this system has been select as the official phase synchronization system for the SKA1-mid telescope. The system is an evolution of Atacama Large Millimeter Array’s distributed ‘photonic local oscillator system’, incorporating key advances made by the international frequency metrology community over the last decade, as well as novel innovations developed by UWA researchers.In this presentation I will describe the technical details of the system; outline how the system's performance was tested using metrology techniques in a laboratory setting, on 186 km of overhead fibre at the South African SKA site, and verified using existing astronomical radio interferometers; and how the system can enhance the astronomical performance of the SKA1-mid telescope.

An All Silicon Feedhorn-Coupled Focal Plane for Cosmic Microwave Background Polarimetry

NASA Technical Reports Server (NTRS)

Hubmayr, J.; Appel, J. W.; Austermann, J. E.; Beall, J. A.; Becker, D.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H. M.;

Hubble Space telescope thermal cycle test report for large solar array samples with BSFR cells (Sample numbers 703 and 704)

NASA Technical Reports Server (NTRS)

Alexander, D. W.

1992-01-01

The Hubble space telescope (HST) solar array was designed to meet specific output power requirements after 2 years in low-Earth orbit, and to remain operational for 5 years. The array, therefore, had to withstand 30,000 thermal cycles between approximately +100 and -100 C. The ability of the array to meet this requirement was evaluated by thermal cycle testing, in vacuum, two 128-cell solar cell modules that exactly duplicated the flight HST solar array design. Also, the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit was evaluated by performing a cold-roll test using one module.

Shack-Hartmann Phasing of Segmented Telescopes: Systematic Effects from Lenslet Arrays

NASA Technical Reports Server (NTRS)

Troy, Mitchell; Chanan, Gary; Roberts, Jennifer

2010-01-01

The segments in the Keck telescopes are routinely phased using a Shack-Hartmann wavefront sensor with sub-apertures that span adjacent segments. However, one potential limitation to the absolute accuracy of this technique is that it relies on a lenslet array (or a single lens plus a prism array) to form the subimages. These optics have the potential to introduce wavefront errors and stray reflections at the subaperture level that will bias the phasing measurement. We present laboratory data to quantify this effect, using measured errors from Keck and two other lenslet arrays. In addition, as part of the design of the Thirty Meter Telescope Alignment and Phasing System we present a preliminary investigation of a lenslet-free approach that relies on Fresnel diffraction to form the subimages at the CCD. Such a technique has several advantages, including the elimination of lenslet aberrations.

Technology Development for AGIS (Advanced Gamma-ray Imaging System).

NASA Astrophysics Data System (ADS)

Krennrich, Frank

2008-04-01

Next-generation arrays of atmospheric Cherenkov telescopes are at the conceptual planning stage and each could consist of on the order of 100 telescopes. The two currently-discussed projects AGIS in the US and CTA in Europe, have the potential to achieve an order of magnitude better sensitivity for Very High Energy (VHE) gamma-ray observations over state-to-the-art observatories. These projects require a substantial increase in scale from existing 4-telescope arrays such as VERITAS and HESS. The optimization of a large array requires exploring cost reduction and research and development for the individual elements while maximizing their performance as an array. In this context, the technology development program for AGIS will be discussed. This includes developing new optical designs, evaluating new types of photodetectors, developing fast trigger systems, integrating fast digitizers into highly-pixilated cameras, and reliability engineering of the individual components.

The CHARA array adaptive optics I: common-path optical and mechanical design, and preliminary on-sky results

NASA Astrophysics Data System (ADS)

Che, Xiao; Sturmann, Laszlo; Monnier, John D.; ten Brummelaar, Theo A.; Sturmann, Judit; Ridgway, Stephen T.; Ireland, Michael J.; Turner, Nils H.; McAlister, Harold A.

2014-07-01

The CHARA array is an optical interferometer with six 1-meter diameter telescopes, providing baselines from 33 to 331 meters. With sub-milliarcsecond angular resolution, its versatile visible and near infrared combiners offer a unique angle of studying nearby stellar systems by spatially resolving their detailed structures. To improve the sensitivity and scientific throughput, the CHARA array was funded by NSF-ATI in 2011 to install adaptive optics (AO) systems on all six telescopes. The initial grant covers Phase I of the AO systems, which includes on-telescope Wavefront Sensors (WFS) and non-common-path (NCP) error correction. Meanwhile we are seeking funding for Phase II which will add large Deformable Mirrors on telescopes to close the full AO loop. The corrections of NCP error and static aberrations in the optical system beyond the WFS are described in the second paper of this series. This paper describes the design of the common-path optical system and the on-telescope WFS, and shows the on-sky commissioning results.

Results from the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Jui, Charles C. H.; Telescope Array Collaboration

2016-04-01

The Telescope Array (TA) is the largest ultrahigh energy cosmic ray detector in the northern hemisphere. The experiment consists of three fluorescence stations viewing the air space over a surface array of 507 scintillation counters deployed over 700 square kilometers. TA has been in operation since 2008. The most recent results from TA, including that of composition studies and search for arrival direction anisotropy, will be presented. We will also report on the progress of the new TA low energy extension (TALE).

Multi-anode microchannel arrays. [for use in ground-based and spaceborne telescopes

NASA Technical Reports Server (NTRS)

Timothy, J. G.; Mount, G. H.; Bybee, R. L.

1979-01-01

The Multi-Anode Microchannel Arrays (MAMA's) are a family of photoelectric, photon-counting array detectors being developed for use in instruments on both ground-based and space-borne telescopes. These detectors combine high sensitivity and photometric stability with a high-resolution imaging capability. MAMA detectors can be operated in a windowless configuration at extreme-ultraviolet and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. Prototype MAMA detectors with up to 512 x 512 pixels are now being tested in the laboratory and telescope operation of a simple (10 x 10)-pixel visible-light detector has been initiated. The construction and modes-of-operation of the MAMA detectors are briefly described and performance data are presented.

Telescope Array Radar (TARA) Observatory for Ultra-High Energy Cosmic Rays

DOE PAGES

Abbasi, R.; Takai, H.; Allen, C.; ...

2014-08-19

Construction was completed during summer 2013 on the Telescope Array RAdar (TARA) bi-static radar observatory for Ultra-High Energy Cosmic Rays (UHECR). TARA is co-located with the Telescope Array, the largest “conventional” cosmic ray detector in the Northern Hemisphere, in radio-quiet Western Utah. TARA employs an 8 MW Effective Radiated Power (ERP) VHF transmitter and smart receiver system based on a 250 MS/s data acquisition system in an effort to detect the scatter of sounding radiation by UHECR-induced atmospheric ionization. TARA seeks to demonstrate bi-static radar as a useful new remote sensing technique for UHECRs. In this report, we describe themore » design and performance of the TARA transmitter and receiver systems.« less

Performance verification of the FlashCam prototype camera for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Werner, F.; Bauer, C.; Bernhard, S.; Capasso, M.; Diebold, S.; Eisenkolb, F.; Eschbach, S.; Florin, D.; Föhr, C.; Funk, S.; Gadola, A.; Garrecht, F.; Hermann, G.; Jung, I.; Kalekin, O.; Kalkuhl, C.; Kasperek, J.; Kihm, T.; Lahmann, R.; Marszalek, A.; Pfeifer, M.; Principe, G.; Pühlhofer, G.; Pürckhauer, S.; Rajda, P. J.; Reimer, O.; Santangelo, A.; Schanz, T.; Schwab, T.; Steiner, S.; Straumann, U.; Tenzer, C.; Vollhardt, A.; Wolf, D.; Zietara, K.; CTA Consortium

2017-12-01

The Cherenkov Telescope Array (CTA) is a future gamma-ray observatory that is planned to significantly improve upon the sensitivity and precision of the current generation of Cherenkov telescopes. The observatory will consist of several dozens of telescopes with different sizes and equipped with different types of cameras. Of these, the FlashCam camera system is the first to implement a fully digital signal processing chain which allows for a traceable, configurable trigger scheme and flexible signal reconstruction. As of autumn 2016, a prototype FlashCam camera for the medium-sized telescopes of CTA nears completion. First results of the ongoing system tests demonstrate that the signal chain and the readout system surpass CTA requirements. The stability of the system is shown using long-term temperature cycling.

Advanced technology optical telescopes IV; Proceedings of the Meeting, Tucson, AZ, Feb. 12-16, 1990. Parts 1 & 2

NASA Technical Reports Server (NTRS)

Barr, Lawrence D. (Editor)

1990-01-01

The present conference on the current status of large, advanced-technology optical telescope development and construction projects discusses topics on such factors as their novel optical system designs, the use of phased arrays, seeing and site performance factors, mirror fabrication and testing, pointing and tracking techniques, mirror thermal control, structural design strategies, mirror supports and coatings, and the control of segmented mirrors. Attention is given to the proposed implementation of the VLT Interferometer, the first diffraction-limited astronomical images with adaptive optics, a fiber-optic telescope using a large cross-section image-transmitting bundle, the design of wide-field arrays, Hartmann test data reductions, liquid mirrors, inertial drives for telescope pointing, temperature control of large honeycomb mirrors, evaporative coatings for very large telescope mirrors, and the W. M. Keck telescope's primary mirror active control system software.

Prototyping hexagonal light concentrators using high-reflectance specular films for the Large-Sized Telescopes of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Okumura, A.; Dang, T. V.; Ono, S.; Tanaka, S.; Hayashida, M.; Hinton, J.; Katagiri, H.; Noda, K.; Teshima, M.; Yamamoto, T.; Yoshida, T.

2017-12-01

We have developed a prototype hexagonal light concentrator for the Large-Sized Telescopes of the Cherenkov Telescope Array. To maximize the photodetection efficiency of the focal-plane camera pixels for atmospheric Cherenkov photons and to lower the energy threshold, a specular film with a very high reflectance of 92-99% has been developed to cover the inner surfaces of the light concentrators. The prototype has a relative anode sensitivity (which can be roughly regarded as collection efficiency) of about 95 to 105% at the most important angles of incidence. The design, simulation, production procedure, and performance measurements of the light-concentrator prototype are reported.

MICRONERVA: A Novel Approach to Large Aperture Astronomical Spectroscopy

NASA Astrophysics Data System (ADS)

Hall, Ryan; Plavchan, Peter; Geneser, Claire; Giddens, Frank; Spangler, Sophia

2016-06-01

MICRONERVA (MICRO Novel Exoplanet Radial Velocity Array) is a project to measure precise spectroscopic radial velocities. The cost of telescopes are a strong function of diameter, and light gathering power as opposed to angular resolution is the fundamental driver for telescope design for many spectroscopic science applications. By sacrificing angular resolution, many multiple smaller fiber-fed telescopes can be combined to synthesize the light gathering power of a larger diameter telescope at a lower effective cost. For our MICRONERVA prototype, based upon the larger MINERVA project, we will attempt to demonstrate that an array of four 8-inch CPC Celestron telescopes can be automated with sufficient active guiding precision for robust nightly robotic operations. The light from each telescope is coupled into single mode fibers, which are conveniently matched to the point spread function of 8-inch telescopes, which can be diffraction limited at red wavelengths in typical seeing at good observing sites. Additionally, the output from an array of single mode fibers provides stable output illumination of a spectrograph, which is a critical requirement of future precise radial velocity instrumentation. All of the hardware from the system is automated using Python programs and ASCOM and MaxIm DL software drivers. We will present an overview of the current status of the project and plans for future work. The detection of exoplanets using the techniques of MICRONERVA could potentially enable cost reductions for many types of spectroscopic research.

Aspherical mirrors for the Gamma-ray Cherenkov Telescope, a Schwarschild-Couder prototype proposed for the future Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Dournaux, J. L.; Gironnet, J.; Huet, J. M.; Laporte, P.; Chadwick, P.; Dumas, D.; Pech, M.; Rulten, C. B.; Sayède, F.; Schmoll, J.; Sol, H.

2016-07-01

The Cherenkov Telescope Array (CTA) project, led by an international collaboration of institutes, aims to create the world's largest next generation Very High-Energy (VHE) gamma-ray telescope array, devoted to observations in a wide band of energy, from a few tens of GeV to more than 100 TeV. The Small-Sized Telescopes (SSTs) are dedicated to the highest energy range. Seventy SSTs are planned in the baseline array design with a required lifetime of about 30 years. The GCT (Gamma-ray Cherenkov Telescope) is one of the prototypes proposed for CTA's SST sub-array. It is based on a Schwarzschild-Couder dual-mirror optical design. This configuration has the benefit of increasing the field-of-view and decreasing the masses of the telescope and of the camera. But, in spite of these many advantages, it was never implemented before in ground-based Cherenkov astronomy because of the aspherical and highly curved shape required for the mirrors. The optical design of the GCT consists of a primary 4 meter diameter mirror, segmented in six aspherical petals, a secondary monolithic 2-meter mirror and a light camera. The reduced number of segments simplifies the alignment of the telescope but complicates the shape of the petals. This, combined with the strong curvature of the secondary mirror, strongly constrains the manufacturing process. The Observatoire de Paris implemented metallic lightweight mirrors for the primary and the secondary mirrors of GCT. This choice was made possible because of the relaxed requirements of optical Cherenkov telescopes compared to optical ones. Measurements on produced mirrors show that these ones can fulfill requirements in shape, PSF and reflectivity, with a clear competition between manufacturing cost and final performance. This paper describes the design of these mirrors in the context of their characteristics and how design optimization was used to produce a lightweight design. The manufacturing process used for the prototype and planned for the large scale production is presented as well as the performance, in terms of geometric and optical properties, of the produced mirrors. The alignment procedure of the mirrors is also detailed. This technique is finally compared to other manufacturing techniques based on composite glass mirrors within the framework of GCT mirrors specificities.

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

NASA Astrophysics Data System (ADS)

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.

New set of solar arrays deployed on Hubble Space Telescope

NASA Image and Video Library

1993-12-09

STS061-99-002 (2-13 Dec 1993) --- The new set of solar array panels deployed on the Hubble Space Telescope (HST) is backdropped against the blackness of space and a widely cloud-covered area on Earth. The 70mm frame was exposed by one of the Space Shuttle Endeavour's seven crew members on the aft flight deck.

Searching for optical transients in real-time : the RAPTOR experiment /.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vestrand, W. T.; Borozdin, K. N.; Brumby, Steven P.

2002-01-01

A rich, but relatively unexplored, region in optical astronomy is the study of transients with durations of less than a day. We describe a wide-field optical monitoring system, RAPTOR, which is designed to identify and make follow-up observations of optical transients in real-time. The system is composed of an array of telescopes that continuously monitor about 1500 square degrees of the sky for transients down to about 12' magnitude in 60 seconds and a central fovea telescope that can reach 16{approx}m' agnitude in 60 seconds. Coupled to the telescope array is a real-time data analysis pipeline that is designed tomore » identify transients on timescales of seconds. In a manner analogous to human vision, the entire array is mounted on a rapidly slewing robotic mount so that the fovea of the array can be rapidly directed at transients identified by the wide-field system. The goal of the project is to develop a ground-based optical system that can reliably identify transients in real-time and ultimately generate alerts with source locations to enable follow-up observations wilh other, larger, telescopes.« less

The Advanced Gamma-ray Imaging System (AGIS): A Nanosecond Time Scale Stereoscopic Array Trigger System.

NASA Astrophysics Data System (ADS)

Krennrich, Frank; Buckley, J.; Byrum, K.; Dawson, J.; Drake, G.; Horan, D.; Krawzcynski, H.; Schroedter, M.

2008-04-01

Imaging atmospheric Cherenkov telescope arrays (VERITAS, HESS) have shown unprecedented background suppression capabilities for reducing cosmic-ray induced air showers, muons and night sky background fluctuations. Next-generation arrays with on the order of 100 telescopes offer larger collection areas, provide the possibility to see the air shower from more view points on the ground, have the potential to improve the sensitivity and give additional background suppression. Here we discuss the design of a fast array trigger system that has the potential to perform a real time image analysis allowing substantially improved background rate suppression at the trigger level.

Highly Uniform 150 mm Diameter Multichroic Polarimeter Array Deployed for CMB Detection

NASA Technical Reports Server (NTRS)

Ho, Shuay-Pwu Patty; Austermann, Jason; Beall, James A.; Choi, Steve K.; Cothard, Nicholas F.; Crowley, Kevin; Datta, Rahul; Devlin, Mark J.; Duff, Shannon M.; Wollack, Edward J.

2016-01-01

The Advanced Atacama Cosmology Telescope Polarimeter is an upgraded receiver for the Atacama Cosmology Telescope, which has begun making measurements of the small angular scale polarization anisotropies in the Cosmic Microwave Background using the first of four new multichroic superconducting detector arrays. Here, we review all details of the optimization and characterization of this first array, which features 2012 AlMn transition edge sensor bolometers operating at 150 and 230 GHz. We present critical temperatures, thermal conductivities,saturation powers, time constants, and sensitivities for the array. The results show high uniformity across the 150 mm wafer and good performance in the field.

A Planar Two-Dimensional Superconducting Bolometer Array for the Green Bank Telescope

NASA Technical Reports Server (NTRS)

Benford, Dominic; Staguhn, Johannes G.; Chervenak, James A.; Chen, Tina C.; Moseley, S. Harvey; Wollack, Edward J.; Devlin, Mark J.; Dicker, Simon R.; Supanich, Mark

2004-01-01

In order to provide high sensitivity rapid imaging at 3.3mm (90GHz) for the Green Bank Telescope - the world's largest steerable aperture - a camera is being built by the University of Pennsylvania, NASA/GSFC, and NRAO. The heart of this camera is an 8x8 close-packed, Nyquist-sampled detector array. We have designed and are fabricating a functional superconducting bolometer array system using a monolithic planar architecture. Read out by SQUID multiplexers, the superconducting transition edge sensors will provide fast, linear, sensitive response for high performance imaging. This will provide the first ever superconducting bolometer array on a facility instrument.

LUNASKA experiments using the Australia Telescope Compact Array to search for ultrahigh energy neutrinos and develop technology for the lunar Cherenkov technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

James, C. W.; Protheroe, R. J.; Ekers, R. D.

2010-02-15

We describe the design, performance, sensitivity and results of our recent experiments using the Australia Telescope Compact Array (ATCA) for lunar Cherenkov observations with a very wide (600 MHz) bandwidth and nanosecond timing, including a limit on an isotropic neutrino flux. We also make a first estimate of the effects of small-scale surface roughness on the effective experimental aperture, finding that contrary to expectations, such roughness will act to increase the detectability of near-surface events over the neutrino energy-range at which our experiment is most sensitive (though distortions to the time-domain pulse profile may make identification more difficult). The aimmore » of our 'Lunar UHE Neutrino Astrophysics using the Square Kilometre Array' (LUNASKA) project is to develop the lunar Cherenkov technique of using terrestrial radio telescope arrays for ultrahigh energy (UHE) cosmic ray (CR) and neutrino detection, and, in particular, to prepare for using the Square Kilometre Array (SKA) and its path-finders such as the Australian SKA Pathfinder (ASKAP) and the Low Frequency Array (LOFAR) for lunar Cherenkov experiments.« less

STS-109 Flight Day 3 Highlights

NASA Technical Reports Server (NTRS)

2002-01-01

This footage from the third day of the STS-109 mission to service the Hubble Space Telescope (HST) begins with the grappling of the HST by the robotic arm of the Columbia Orbiter, operated by Mission Specialist Nancy Currie. During the grappling, numerous angles deliver close-up images of the telescope which appears to be in good shape despite many years in orbit around the Earth. Following the positioning of the HST on its berthing platform in the Shuttle bay, the robotic arm is used to perform an external survey of the telescope. Some cursory details are given about different equipment which will be installed on the HST including a replacement cooling system for the Near Infrared Camera Multi-Object Spectrometer (NICMOS) and the Advanced Camera for Surveys. Following the survey, there is footage of the retraction of both of the telescope's two flexible solar arrays, which was successful. These arrays will be replaced by rigid solar arrays with decreased surface area and increased performance.

Long-baseline optical intensity interferometry. Laboratory demonstration of diffraction-limited imaging

NASA Astrophysics Data System (ADS)

Dravins, Dainis; Lagadec, Tiphaine; Nuñez, Paul D.

2015-08-01

Context. A long-held vision has been to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, and reveal interacting gas flows in binary systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and also used for intensity interferometry. Second-order spatial coherence of light is obtained by cross correlating intensity fluctuations measured in different pairs of telescopes. With no optical links between them, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are approximately one meter, making the method practically immune to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Aims: Previous theoretical modeling has shown that full images should be possible to retrieve from observations with such telescope arrays. This project aims at verifying diffraction-limited imaging experimentally with groups of detached and independent optical telescopes. Methods: In a large optics laboratory, artificial stars (single and double, round and elliptic) were observed by an array of small telescopes. Using high-speed photon-counting solid-state detectors and real-time electronics, intensity fluctuations were cross-correlated over up to 180 baselines between pairs of telescopes, producing coherence maps across the interferometric Fourier-transform plane. Results: These interferometric measurements were used to extract parameters about the simulated stars, and to reconstruct their two-dimensional images. As far as we are aware, these are the first diffraction-limited images obtained from an optical array only linked by electronic software, with no optical connections between the telescopes. Conclusions: These experiments serve to verify the concepts for long-baseline aperture synthesis in the optical, somewhat analogous to radio interferometry.

Characterization and commissioning of the SST-1M camera for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Aguilar, J. A.; Bilnik, W.; Błocki, J.; Bogacz, L.; Borkowski, J.; Bulik, T.; Cadoux, F.; Christov, A.; Curyło, M.; della Volpe, D.; Dyrda, M.; Favre, Y.; Frankowski, A.; Grudnik, Ł.; Grudzińska, M.; Heller, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandat, D.; Marszałek, A.; Medina Miranda, L. D.; Michałowski, J.; Moderski, R.; Montaruli, T.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Pech, M.; Porcelli, A.; Prandini, E.; Rajda, P.; Rameez, M.; Schioppa, E., Jr.; Schovanek, P.; Seweryn, K.; Skowron, K.; Sliusar, V.; Sowiński, M.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Toscano, S.; Troyano Pujadas, I.; Walter, R.; Wiȩcek, M.; Zagdański, A.; Ziȩtara, K.; Żychowski, P.

2017-02-01

The Cherenkov Telescope Array (CTA), the next generation very high energy gamma-rays observatory, will consist of three types of telescopes: large (LST), medium (MST) and small (SST) size telescopes. The SSTs are dedicated to the observation of gamma-rays with energy between a few TeV and a few hundreds of TeV. The SST array is expected to have 70 telescopes of different designs. The single-mirror small size telescope (SST-1 M) is one of the proposed telescope designs under consideration for the SST array. It will be equipped with a 4 m diameter segmented mirror dish and with an innovative camera based on silicon photomultipliers (SiPMs). The challenge is not only to build a telescope with exceptional performance but to do it foreseeing its mass production. To address both of these challenges, the camera adopts innovative solutions both for the optical system and readout. The Photo-Detection Plane (PDP) of the camera is composed of 1296 pixels, each made of a hollow, hexagonal light guide coupled to a hexagonal SiPM designed by the University of Geneva and Hamamatsu. As no commercial ASIC would satisfy the CTA requirements when coupled to such a large sensor, dedicated preamplifier electronics have been designed. The readout electronics also use an innovative approach in gamma-ray astronomy by adopting a fully digital approach. All signals coming from the PDP are digitized in a 250 MHz Fast ADC and stored in ring buffers waiting for a trigger decision to send them to the pre-processing server where calibration and higher level triggers will decide whether the data are stored. The latest generation of FPGAs is used to achieve high data rates and also to exploit all the flexibility of the system. As an example each event can be flagged according to its trigger pattern. All of these features have been demonstrated in laboratory measurements on realistic elements and the results of these measurements will be presented in this contribution.

Measurement of the proton-air cross section with Telescope Array's Middle Drum detector and surface array in hybrid mode

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.; Telescope Array Collaboration

2015-08-01

In this work we are reporting on the measurement of the proton-air inelastic cross section σp-air inel using the Telescope Array detector. Based on the measurement of the σp-air inel, the proton-proton cross section σp -p value is also determined at √{s }=9 5-8+5 TeV . Detecting cosmic ray events at ultrahigh energies with the Telescope Array enables us to study this fundamental parameter that we are otherwise unable to access with particle accelerators. The data used in this report are the hybrid events observed by the Middle Drum fluorescence detector together with the surface array detector collected over five years. The value of the σp-air inel is found to be equal to 567.0 ±70.5 [Stat]-25+29[Sys] mb . The total proton-proton cross section is subsequently inferred from Glauber formalism and the Block, Halzen and Stanev QCD inspired fit and is found to be equal to 17 0-44+48[Stat]-17+19[Sys] mb .

Performance of the Gamma-ray Cherenkov Telescope structure: a dual-mirror telescope prototype proposed for the future Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Dournaux, J. L.; Amans, J. P.; Dangeon, L.; Fasola, G.; Gironnet, J.; Huet, J. M.; Laporte, P.; Abchiche, A.; Barkaoui, S.; Bousquet, J. J.; Buchholtz, G.; Dumas, D.; Gaudemard, J.; Jégouzo, I.; Poinsignon, P.; Vergne, L.; Sol, H.

2016-07-01

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 from 20 GeV to above 100 TeV. Because of this wide energy band, three classes of telescopes, associated with different energy ranges and different mirror sizes, are defined. The Small Size Telescopes (SSTs) are associated with the highest energy range. Seventy of these telescopes are foreseen on the Southern site of the CTA. The large number of telescopes constrains their mechanical structure because easy maintenance and reduced cost per telescope are needed. Moreover, of course, the design shall fulfill the required performance and lifetime in the environment conditions of the site. The Observatoire de Paris started design studies in 2011 of the mechanical structure of the GCT (Gamma-ray Cherenkov Telescope), a four-meter prototype telescope for the SSTs of CTA, from optical and preliminary mechanical designs made by the University of Durham. At the end of 2014 these studies finally resulted in a lightweight ( 8 tons) and stiff design. This structure was based on the dual-mirror Schwarzschild-Couder (SC) optical design, which is an interesting and innovative alternative to the one-mirror Davies-Cotton design commonly used in ground-based Cherenkov astronomy. The benefits of such a design are many since it enables a compact structure, lightweight camera and a good angular resolution across the entire field-of-view. The mechanical structure was assembled on the Meudon site of the Observatoire de Paris in spring 2015. The secondary mirror, panels of the primary mirror and the Telescope Control System were successfully implemented afterwards leading now to a fully operational telescope. This paper focuses on the mechanics of the telescope prototype. It describes the mechanical structure and presents its performance identified from computations or direct measurements. Upgrades of the design in the context of the preproduction and the large scale CTA production are also discussed.

VizieR Online Data Catalog: 8 Fermi GRB afterglows follow-up (Singer+, 2015)

NASA Astrophysics Data System (ADS)

Singer, L. P.; Kasliwal, M. M.; Cenko, S. B.; Perley, D. A.; Anderson, G. E.; Anupama, G. C.; Arcavi, I.; Bhalerao, V.; Bue, B. D.; Cao, Y.; Connaughton, V.; Corsi, A.; Cucchiara, A.; Fender, R. P.; Fox, D. B.; Gehrels, N.; Goldstein, A.; Gorosabel, J.; Horesh, A.; Hurley, K.; Johansson, J.; Kann, D. A.; Kouveliotou, C.; Huang, K.; Kulkarni, S. R.; Masci, F.; Nugent, P.; Rau, A.; Rebbapragada, U. D.; Staley, T. D.; Svinkin, D.; Thone, C. C.; de Ugarte Postigo, A.; Urata, Y.; Weinstein, A.

2015-10-01

In this work, we present the GBM-iPTF (intermediate Palomar Transient Factory) afterglows from the first 13 months of this project. Follow-up observations include R-band photometry from the P48, multicolor photometry from the P60, spectroscopy (acquired with the P200, Keck, Gemini, APO, Magellan, Very Large Telescope (VLT), and GTC), and radio observations with the Very Large Array (VLA), the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the Australia Telescope Compact Array (ATCA), and the Arcminute Microkelvin Imager (AMI). (3 data files).

Remote access and operation of telescopes by the scientific users

NASA Astrophysics Data System (ADS)

Edwards, P. G.; Amy, S.; Brodrick, D.; Carretti, E.; Hoyle, S.; Indermuehle, B.; McConnell, D.; Mader, S.; Mirtschin, P.; Preisig, B.; Smith, M.; Stevens, J.; Wark, R.; Wieringa, M.; Wu, X.

2014-08-01

The Australia Telescope National Facility operates three radio telescopes: the Parkes 64m Telescope, the Australia Telescope Compact Array (ATCA), and the Mopra 22m Telescope. Scientific operation of all these is conducted by members of the investigating teams rather than by professional operators. All three can now be accessed and controlled from any location served by the internet, the telescopes themselves being unattended for part or all of the time. Here we describe the rationale, advantages, and means of implementing this operational model.

Dynamic scheduling and planning parallel observations on large Radio Telescope Arrays with the Square Kilometre Array in mind

NASA Astrophysics Data System (ADS)

Buchner, Johannes

2011-12-01

Scheduling, the task of producing a time table for resources and tasks, is well-known to be a difficult problem the more resources are involved (a NP-hard problem). This is about to become an issue in Radio astronomy as observatories consisting of hundreds to thousands of telescopes are planned and operated. The Square Kilometre Array (SKA), which Australia and New Zealand bid to host, is aiming for scales where current approaches -- in construction, operation but also scheduling -- are insufficent. Although manual scheduling is common today, the problem is becoming complicated by the demand for (1) independent sub-arrays doing simultaneous observations, which requires the scheduler to plan parallel observations and (2) dynamic re-scheduling on changed conditions. Both of these requirements apply to the SKA, especially in the construction phase. We review the scheduling approaches taken in the astronomy literature, as well as investigate techniques from human schedulers and today's observatories. The scheduling problem is specified in general for scientific observations and in particular on radio telescope arrays. Also taken into account is the fact that the observatory may be oversubscribed, requiring the scheduling problem to be integrated with a planning process. We solve this long-term scheduling problem using a time-based encoding that works in the very general case of observation scheduling. This research then compares algorithms from various approaches, including fast heuristics from CPU scheduling, Linear Integer Programming and Genetic algorithms, Branch-and-Bound enumeration schemes. Measures include not only goodness of the solution, but also scalability and re-scheduling capabilities. In conclusion, we have identified a fast and good scheduling approach that allows (re-)scheduling difficult and changing problems by combining heuristics with a Genetic algorithm using block-wise mutation operations. We are able to explain and eradicate two problems in the literature: The inability of a GA to properly improve schedules and the generation of schedules with frequent interruptions. Finally, we demonstrate the scheduling framework for several operating telescopes: (1) Dynamic re-scheduling with the AUT Warkworth 12m telescope, (2) Scheduling for the Australian Mopra 22m telescope and scheduling for the Allen Telescope Array. Furthermore, we discuss the applicability of the presented scheduling framework to the Atacama Large Millimeter/submillimeter Array (ALMA, in construction) and the SKA. In particular, during the development phase of the SKA, this dynamic, scalable scheduling framework can accommodate changing conditions.

Tradespace investigation of strategic design factors for large space telescopes

NASA Astrophysics Data System (ADS)

Karlow, Brandon; Jewison, Christopher; Sternberg, David; Hall, Sherrie; Golkar, Alessandro

2015-04-01

Future large telescope arrays require careful balancing of satisfaction across the stakeholders' community. Development programs usually cannot afford to explicitly address all stakeholder tradeoffs during the conceptual design stage, but rather confine the analysis to performance, cost, and schedule discussions, treating policy and budget as constraints defining the envelope of the investigation. Thus, it is of interest to develop an integrated stakeholder analysis approach to explicitly address the impact of all stakeholder interactions on the design of large telescope arrays to address future science and exploration needs. This paper offers a quantitative approach for modeling some of the stakeholder influences relevant to large telescope array designs-the linkages between a given mission and the wider NASA community. The main goal of the analysis is to explore the tradespace of large telescope designs and understand the effects of different design decisions in the stakeholders' network. Proposed architectures that offer benefits to existing constellations of systems, institutions, and mission plans are expected to yield political and engineering benefits for NASA stakeholders' wider objectives. If such synergistic architectures are privileged in subsequent analysis, regions of the tradespace that better meet the needs of the wider NASA community can be selected for further development.

Physical structure of the IRC+10216 wind: Molecular sidereoarcheology

NASA Technical Reports Server (NTRS)

Skinner, C. J.; Justtanont, K.; Tielens, Alexander G. G. M.; Betz, A. L.; Boreiko, R. T.

1995-01-01

We present KAO observations of the CO J=9-8 and 12-11 lines in the C-star IRC+10216; these are the highest rotational transitions so far observed in any AGB star. A model is developed for the CO emission by IRC+10216 in all the observed CO rotational transitions.

EVA 2 - MS Newman and Massimino over Australia

NASA Image and Video Library

2002-03-05

STS109-E-5610 (5 March 2002) --- Astronauts James H. Newman, attached to the Remote Manipulator System (RMS) arm of the Space Shuttle Columbia, and Michael J. Massimino (barely visible against the Hubble Space Telescope near center frame) work on the telescope as the shuttle flies over Australia. This day's space walk went on to see astronauts Newman and Massimino replace the port solar array on the Hubble. On the previous day astronauts John M. Grunsfeld and Richard M. Linnehan replaced the starboard solar array on the giant telescope. The image was recorded with a digital still camera.

Proceedings of the Third Infrared Detector Technology Workshop

NASA Technical Reports Server (NTRS)

Mccreight, Craig R. (Compiler)

1989-01-01

This volume consists of 37 papers which summarize results presented at the Third Infrared Detector Technology Workshop, held February 7-9, 1989, at Ames Research Center. The workshop focused on infrared (IR) detector, detector array, and cryogenic electronic technologies relevant to low-background space astronomy. Papers on discrete IR detectors, cryogenic readouts, extrinsic and intrinsic IR arrays, and recent results from ground-based observations with integrated arrays were given. Recent developments in the second-generation Hubble Space Telescope (HST) infrared spectrometer and in detectors and arrays for the European Space Agency's Infrared Space Observatory (ISO) are also included, as are status reports on the Space Infrared Telescope Facility (SIRTF) and the Stratospheric Observatory for Infrared Astronomy (SOFIA) projects.

Facilities for US Radioastronomy.

ERIC Educational Resources Information Center

Thaddeus, Patrick

1982-01-01

Discusses major developments in radioastronomy since 1945. Topics include proposed facilities, very-long-baseline interferometric array, millimeter-wave telescope, submillimeter-wave telescope, and funding for radioastronomy facilities and projects. (JN)

Innovative compact focal plane array for wide field vis and ir orbiting telescopes

NASA Astrophysics Data System (ADS)

Hugot, Emmanuel; Vives, Sébastien; Ferrari, Marc; Gaeremynck, Yann; Jahn, Wilfried

2017-11-01

The future generation of high angular resolution space telescopes will require breakthrough technologies to combine large diameters and large focal plane arrays with compactness and lightweight mirrors and structures. Considering the allocated volume medium-size launchers, short focal lengths are mandatory, implying complex optical relays to obtain diffraction limited images on large focal planes. In this paper we present preliminary studies to obtain compact focal plane arrays (FPA) for earth observations on low earth orbits at high angular resolution. Based on the principle of image slicers, we present an optical concept to arrange a 1D FPA into a 2D FPA, allowing the use of 2D detector matrices. This solution is particularly attractive for IR imaging requiring a cryostat, which volume could be considerably reduced as well as the relay optics complexity. Enabling the use of 2D matrices for such an application offers new possibilities. Recent developments on curved FPA allows optimization without concerns on the field curvature. This innovative approach also reduces the complexity of the telescope optical combination, specifically for fast telescopes. This paper will describe the concept and optical design of an F/5 - 1.5m telescope equipped with such a FPA, the performances and the impact on the system with a comparison with an equivalent 1.5m wide field Korsch telescope.

Hubble Space Telescope Servicing begins.

NASA Astrophysics Data System (ADS)

1993-12-01

The day's work began when astronauts Story Musgrave and Jeff Hoffman stepped out into the cargo bay at 9h41 pm CST, Saturday (4h41 am CET, Sunday). They immediately set to work replacing two gyroscope assemblies, known as the Rate Sensor Units, two associated electronics boxes, called Electronic Control Units, and eight electrical fuse plugs. The work was completed ahead of schedule, but the astronauts had trouble closing the doors of the compartment housing the gyros and took over an hour to get them shut. The astronauts also prepared equipment for the replacement of the solar arrays. "The feeling down here is one of great satisfaction for a tremendous job today" said spacecraft communicator Greg Harbaugh in mission control. "We are very proud of the work that you all did and we are very confident in the continued success of the mission. Everything is going great and tomorrow is going to be another great day". ESA astronaut Claude Nicollier played a vital role during the spacewalk moving the astronauts and their equipment around the cargo bay with the shuttle's robot arm. The Hubble Space Telescope servicing mission features more robot arm operations than any other shuttle flight. The telescope's left-hand solar array was rolled up successfully at 6h24 am CST (1h24 pm CET). The 11-tonne observatory was rotated 180 degrees on its turntable before commands were sent to retract the second array at 8h23 am CST (3h23 pm CET). The crew stopped the retraction when it appeared the system may have jammed. Mission control instructed the crew to jettison the array, a procedure that they have trained for. Tomorrow astronauts Kathy Thornton and Tom Akers will make a six-hour spacewalk to jettison the troublesome wing, store the other in the cargo bay, and install two new panels supplied by ESA. The second set of arrays feature thermal shields and a modified thermal compensation system to prevent the flexing that affected the first pair. The Hubble Space Telescope was plucked from orbit this Saturday by ESA astronaut Claude Nicollier, operating the shuttle's robot arm. The Swiss-born astronaut gripped the 11- tonne observatory with the shuttle's 15-metre long robot arm at 2h34 am CST (9h34 am CET) after a two-day chase through space as the two spacecraft flew over the South Pacific Ocean. "Endeavour has a firm handshake with Mr. Hubble's telescope" said mission commander Dick Covey. "It's quite a sight". About half an hour later Nicollier had the telescope berthed on a special turntable in the back of the Shuttle's cargo bay. Later he used the camera at the end of the arm to surveyed the telescope for any damage. As the shuttle approached the telescope the astronauts first reported that one of the twin solar arrays appeared to be bowed and twisted. ESA officials said the problem was caused by the failure in early 1992 of the tensioning system on one side of the right-hand array. The system is designed to allow the blanket-like array to expand and contract in orbit. That failure placed stress on one of the supporting bi-stem booms resulting in its bent condition. Endeavour's mission began Thursday 2 December and will end 13 December. A total of five spacewalks are planned to service the telescope.

OHANA, the Optical Hawaiian Array for Nanoradian Astronomy. Towards kilometric infrared arrays

NASA Astrophysics Data System (ADS)

Perrin, G.

Optical/Infrared Interferometry has become a mature technique with more and more astrophysical results in the past years. For historical and technical reasons, the traditional field of investigation of interferometers is stellar physics. With the advent of large telescopes and adaptive optics, more resolving and more sensitive interferometers are within reach with the promise to widen the target list. In particular, extragalactic sources will benefit from this revolution. A prototype instrument, 'OHANA, is described here. 'OHANA uses single-mode fibers to turn the large telescopes of the Mauna Kea summit into a large near-infrared kilometric array.

NECTAr: New electronics for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Vorobiov, S.; Bolmont, J.; Corona, P.; Delagnes, E.; Feinstein, F.; Gascón, D.; Glicenstein, J.-F.; Naumann, C. L.; Nayman, P.; Sanuy, A.; Toussenel, F.; Vincent, P.

2011-05-01

The European astroparticle physics community aims to design and build the next generation array of Imaging Atmospheric Cherenkov Telescopes (IACTs), that will benefit from the experience of the existing H.E.S.S. and MAGIC detectors, and further expand the very-high energy astronomy domain. In order to gain an order of magnitude in sensitivity in the 10 GeV to >100TeV range, the Cherenkov Telescope Array (CTA) will employ 50-100 mirrors of various sizes equipped with 1000-4000 channels per camera, to be compared with the 6000 channels of the final H.E.S.S. array. A 3-year program, started in 2009, aims to build and test a demonstrator module of a generic CTA camera. We present here the NECTAr design of front-end electronics for the CTA, adapted to the trigger and data acquisition of a large IACTs array, with simple production and maintenance. Cost and camera performances are optimized by maximizing integration of the front-end electronics (amplifiers, fast analog samplers, ADCs) in an ASIC, achieving several GS/s and a few μs readout dead-time. We present preliminary results and extrapolated performances from Monte Carlo simulations.

First Results from the Telescope Array RAdar (TARA) Detector

NASA Astrophysics Data System (ADS)

Myers, Isaac

2014-03-01

The TARA cosmic ray detector has been in operation for about a year and a half. This bi-static radar detector was designed with the goal of detecting cosmic rays in coincidence with Telescope Array (TA). A new high power (25 kW, 5 MW effective radiated power) transmitter and antenna array and 250 MHz fPGA-based DAQ have been operational since August 2013. The eight-Yagi antenna array broadcasts a 54.1 MHz tone across the TA surface detector array toward our receiver station 50 km away at the Long Ridge fluorescence detector. Receiving antennas feed an intelligent DAQ that self-adjusts to the fluctuating radio background and which employs a bank of matched filters that search in real-time for chirp radar echoes. Millions of triggers have been collected in this mode. A second mode is a forced trigger scheme that uses the trigger status of the fluorescence telescope. Of those triggers collected in FD-triggered mode, about 800 correspond with well-reconstructed TA events. I will describe recent advancements in calibrating key components in the transmitter and receiver RF chains and the analysis of FD-triggered data. Work supported by W.M. Keck Foundation and NSF.

SMARTS 1.3-m Telescope | CTIO

Science.gov Websites

Visitor's Computer Guidelines Network Connection Request Instruments Instruments by Telescope IR Instruments telescope before SMARTS took over its operation. A permanently-mounted, dual-channel, optical-IR imager Consortium) with the optical detector since the 1998B semester. The IR array was installed in July 1999

The EEE Project: a sparse array of telescopes for the measurement of cosmic ray muons

NASA Astrophysics Data System (ADS)

La Rocca, P.; Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccetti, F.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferraro, A.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; Liciulli, F.; Maggiora, A.; Maragoto Rodriguez, O.; Maron, G.; Martelli, B.; Mazziotta, M. N.; Miozzi, S.; Nania, R.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M.; Paoletti, R.; Park, W.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Rizzi, M.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Stori, L.; Taiuti, M.; Terreni, G.; Visnyei, O. B.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

2016-12-01

The Extreme Energy Events (EEE) Project is meant to be the most extensive experiment to detect secondary cosmic particles in Italy. To this aim, more than 50 telescopes have been built at CERN and installed in high schools distributed all over the Italian territory. Each EEE telescope comprises three large area Multigap Resistive Plate Chambers (MRPCs) and is capable of reconstructing the trajectories of the charged particles traversing it with a good angular resolution. The excellent performance of the EEE telescopes allows a large variety of studies, from measuring the local muon flux in a single telescope, to detecting extensive air showers producing time correlations in the same metropolitan area, to searching for large-scale correlations between showers detected in telescopes tens, hundreds or thousands of kilometers apart. In addition to its scientific goal, the EEE Project also has an educational and outreach objective, its aim being to motivate young people by involving them directly in a real experiment. High school students and teachers are involved in the construction, testing and start-up of the EEE telescope in their school, then in its maintenance and data-acquisition, and later in the analysis of the data. During the last couple of years a great boost has been given to the EEE Project through the organization of simultaneous and centralized data taking with the whole telescope array. The raw data from all telescopes are transferred to CNAF (Bologna), where they are reconstructed and stored. The data are currently being analyzed, looking at various topics: variation of the rate of cosmic muons with time, upward going muons, muon lifetime, search for anisotropies in the muon angular distribution and for time coincidences between stations. In this paper an overall description of the experiment is given, including the design, construction and performance of the telescopes. The operation of the whole array is also presented by showing the most recent physics results.

The Space Infrared Interferometric Telescope (SPIRIT)

NASA Technical Reports Server (NTRS)

Rinehart, Stephen

2007-01-01

The Space Infrared Interferometric Telescope (SPIRIT) is a candidate NASA Origins Probe Mission. SPIRIT is a two-telescope Michelson interferometer covering wavelengths from 25-400 microns, providing simultaneously high spectral resolution and high angular resolution. With comparable sensitivity to Spitzer, but two orders of magnitude improvement in angular resolution, SPIRIT will enable us to address a wide array of compelling scientific questions, including how planetary systems form in disks and how new planets interact with the disk. Further, SPIRIT will lay the technological groundwork for an array of future interferometry missions with ambitious scientific goals, including the Terrestrial Planet Finder Interferometer / Darwin, and the Submillimeter Probe of the Evolution of Cosmic Structure.

The Space Infrared Interferometric Telescope (SPIRIT)

NASA Technical Reports Server (NTRS)

Rinehart, Stephen

2007-01-01

The Space Infrared Interferometric Telescope (SPIRIT) is a candidate NASA Origins Probe Mission. SPIRIT is a two-telescope Michelson interferometer covering wavelengths from 25-400 microns, providing simultaneously high spectral resolution and high angular resolution. With comparable sensitivity to Spitzer, but two orders of magnitude improvement in angular resolution, SPIRIT will enable us to address a wide array of compelling scientific questions, including how planetary systems form in disks and how new planets interact with the disk. Further, SPIRIT will lay the technological groundwork for an array of future interferometry missions with ambitious scientific goals, including the Terrestrial Planet Finder Interferometer/Darwin, and the Submillimeter Probe of the Evolution of Cosmic Structure.

Track reconstruction and background rejection for the Baikal neutrino telescope

NASA Astrophysics Data System (ADS)

Belolaptikov, I. A.; Djilkibaev, J.-A. M.; Domogatsky, G. V.; Klimushin, S. I.; Krabi, J.; Lanin, O. Ju.; Osipova, E. A.; Pavlov, A. A.; Spiering, Ch.; Wischnewski, R.

1994-05-01

We describe procedures to reconstruct muon tracks in the Baikal Neutrino Telescope including effective filtering of badly reconstructed events. Special attention is payed to reject downward going muons faking upward going muons from neutrino interactions. It is shown that a rejection factor of 106-as it is needed to operate a neutrino telescope at 1100 m.w.e. depth - can be obtained with a 200 PMT array. We present first results from NT-36, the 1993 array consisting of 36 PMTs. We observe satisfying agreement between Monte Carlo results and experimental data. This gives us confidence to our simulations of the full detector.

On the prospects of cross-calibrating the Cherenkov Telescope Array with an airborne calibration platform

NASA Astrophysics Data System (ADS)

Brown, Anthony M.

2018-01-01

Recent advances in unmanned aerial vehicle (UAV) technology have made UAVs an attractive possibility as an airborne calibration platform for astronomical facilities. This is especially true for arrays of telescopes spread over a large area such as the Cherenkov Telescope Array (CTA). In this paper, the feasibility of using UAVs to calibrate CTA is investigated. Assuming a UAV at 1km altitude above CTA, operating on astronomically clear nights with stratified, low atmospheric dust content, appropriate thermal protection for the calibration light source and an onboard photodiode to monitor its absolute light intensity, inter-calibration of CTA's telescopes of the same size class is found to be achievable with a 6 - 8 % uncertainty. For cross-calibration of different telescope size classes, a systematic uncertainty of 8 - 10 % is found to be achievable. Importantly, equipping the UAV with a multi-wavelength calibration light source affords us the ability to monitor the wavelength-dependent degradation of CTA telescopes' optical system, allowing us to not only maintain this 6 - 10 % uncertainty after the first few years of telescope deployment, but also to accurately account for the effect of multi-wavelength degradation on the cross-calibration of CTA by other techniques, namely with images of air showers and local muons. A UAV-based system thus provides CTA with several independent and complementary methods of cross-calibrating the optical throughput of individual telescopes. Furthermore, housing environmental sensors on the UAV system allows us to not only minimise the systematic uncertainty associated with the atmospheric transmission of the calibration signal, it also allows us to map the dust content above CTA as well as monitor the temperature, humidity and pressure profiles of the first kilometre of atmosphere above CTA with each UAV flight.

Observations with the High Altitude GAmma Ray (HAGAR) telescope array in the Indian Himalayas

NASA Astrophysics Data System (ADS)

Britto, R. J.; Acharya, B. S.; Anupama, G. C.; Bhatt, N.; Bhattacharjee, P.; Bhattacharya, S. S.; Chitnis, V. R.; Cowsik, R.; Dorji, N.; Duhan, S. K.; Gothe, K. S.; Kamath, P. U.; Koul, R.; Mahesh, P. K.; Mitra, A.; Nagesh, B. K.; Parmar, N. K.; Prabhu, T. P.; Rannot, R. C.; Rao, S. K.; Saha, L.; Saleem, F.; Saxena, A. K.; Sharma, S. K.; Shukla, A.; Singh, B. B.; Srinivasan, R.; Srinivasulu, G.; Sudersanan, P. V.; Tickoo, A. K.; Tsewang, D.; Upadhya, S.; Vishwanath, P. R.; Yadav, K. K.

2010-12-01

For several decades, it was thought that astrophysical sources emit high energy photons within the energy range of the gamma-ray region of the electromagnetic spectrum also. These photons originate from interactions of high energy particles from sources involving violent phenomena in the Universe (supernovae, pulsars, Active Galactic Nuclei, etc.) with gas and radiation fields. Since the first reliable detections of cosmic gamma rays in the 1970's, improvements in instrumentation have led gamma-ray astronomy to an established branch of modern Astrophysics, with a constant increase in the number of detected sources. But the 30-300 GeV energy range remained sparsely explored until the launch of the Fermi space telescope in June 2008. The ground-based gamma-ray telescope array HAGAR is the first array of atmospheric Cherenkov telescopes established at a so high altitude (4270 m a.s.l.), and was designed to reach a relatively low energy threshold with quite a low mirror area (31 m^2). It is located at Hanle in India, in the Ladakh region of the Himalayas. Regular source observations have begun with the complete setup of 7 telescopes on Sept. 2008. We report and discuss our estimation of the systematics through dark region studies, and present preliminary results from gamma-ray sources in this paper.

Torsional Buckling Tests of a Simulated Solar Array

NASA Technical Reports Server (NTRS)

Thornton, E. A.

1996-01-01

Spacecraft solar arrays are typically large structures supported by long, thin deployable booms. As such, they may be particularly susceptible to abnormal structural behavior induced by mechanical and thermal loading. One example is the Hubble Space Telescope solar arrays which consist of two split tubes fit one inside the other called BiSTEMs. The original solar arrays on the Hubble Space Telescope were found to be severely twisted following deployment and later telemetry data showed the arrays were vibrating during daylight to night and night to daylight transition. The solar array twist however can force the BiSTEM booms to change in cross-section and cause tile solar arrays to react unpredictably to future loading. The solar arrays were redesigned to correct for tile vibration, however, upon redeployment they again twisted. To assess the influence of boom cross-sectional configuration, experiments were conducted on two types of booms, (1)booms with closed cross-sections, and (2) booms with open cross-sections. Both models were subjected to compressive loading and imposed tip deflections. An existing analytical model by Chung and Thornton was used to define the individual load ranges for each model solar array configuration. The load range for the model solar array using closed cross-section booms was 0-120 Newtons and 0-160 Newtons for the model solar array using open cross-section booms. The results indicate the model solar array with closed cross-section booms buckled only in flexure. However, the results of the experiment with open cross-section booms indicate the model solar array buckled only in torsion and with imposed tip deflections the cross section can degrade by rotation of the inner relative to the outer STEM. For tile Hubble Space Telescope solar arrays the results of these experiments indicate the twisting resulted from the initial mechanical loading of the open cross-section booms.

Multi-Spectral Solar Telescope Array. IV - The soft X-ray and extreme ultraviolet filters

NASA Technical Reports Server (NTRS)

Lindblom, Joakim F.; O'Neal, Ray H.; Walker, Arthur B. C., Jr.; Powell, Forbes R.; Barbee, Troy W., Jr.; Hoover, Richard B.

1991-01-01

NASA's Multi-Spectral Solar Telescope Array uses various combinations of thin foil filters composed of Al, C, Te, Be, Mo, Rh, and phthalocyanine to achieve the requisite radiation-rejection characteristics. Such rejection is demanded by the presence of strong EUV radiation at longer wavelengths where the specular reflectivity of multilayer mirrors can cause 'contamination' of the image in the narrow band defined by the Bragg condition.

Telescope Array Control System Based on Wireless Touch Screen Platform

NASA Astrophysics Data System (ADS)

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

2016-07-01

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

Telescope Array Control System Based on Wireless Touch Screen Platform

NASA Astrophysics Data System (ADS)

Fu, Xia-nan; Huang, Lei; Wei, Jian-yan

2017-10-01

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

The Full-Scale Prototype for the Fluorescence Detector Array of Single-Pixel Telescopes

NASA Astrophysics Data System (ADS)

Fujii, T.; Malacari, M.; Bellido, J. A.; Farmer, J.; Galimova, A.; Horvath, P.; Hrabovsky, M.; Mandat, D.; Matalon, A.; Matthews, J. N.; Merolle, M.; Ni, X.; Nozka, L.; Palatka, M.; Pech, M.; Privitera, P.; Schovanek, P.; Thomas, S. B.; Travnicek, P.

The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a design concept for the next generation of ultrahigh-energy cosmic ray (UHECR) observatories, addressing the requirements for a large-area, low-cost detector suitable for measuring the properties of the highest energy cosmic rays. In the FAST design, a large field of view is covered by a few pixels at the focal plane of a mirror or Fresnel lens. Motivated by the successful detection of UHECRs using a prototype comprised of a single 200 mm photomultiplier-tube and a 1 m2 Fresnel lens system, we have developed a new "full-scale" prototype consisting of four 200 mm photomultiplier-tubes at the focus of a segmented mirror of 1.6 m in diameter. We report on the status of the full-scale prototype, including test measurements made during first light operation at the Telescope Array site in central Utah, U.S.A.

Quality Control of The Miniature Exoplanet Radio Velocity Array(MINERVA)

NASA Astrophysics Data System (ADS)

Rivera García, Kevin O.; Eastman, Jason D.

2017-01-01

The MINiature Exoplanet Radial Velocity Array, also known as MINERVA , is a network of four robotic 0.7 meter telescopes that is conducting a Radial Velocity survey of the nearest, brightest stars in search of small and rocky exoplanets. The robotic telescope array is located in Fred Lawrence Whipple Observatory in Arizona. MINERVA began science operations in 2015 and we are constantly improving its observing efficiency. We will describe performance statistics that we have developed in Python to proactively identify problems before they impede observations. We have written code to monitor the pointing error for each telescope to ensure it will always be able to acquire a target in the 3 arcminute field of view of its acquisition camera, but there are still some issues that need to be identified. The end goal for this research is to automatically address any common malfunction that may cause the observation to fail and ultimately improve our observing efficiency.

MROI Array telescopes: the relocatable enclosure domes

NASA Astrophysics Data System (ADS)

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.

Directions for Space-Based Low-Frequency Radio Astronomy 2. Telescopes

NASA Astrophysics Data System (ADS)

Basart, J. P.; Burns, J. O.; Dennison, B. K.; Weiler, K. W.; Kassim, N. E.; Castillo, S. P.; McCune, B. M.

Astronomical studies of celestial sources at low radio frequencies (0.3 to 30 MHz) lag far behind the investigations of celestial sources at high radio frequencies. In a companion paper [Basart et al., this issue] we discussed the need for low-frequency investigations, and in this paper we discuss the telescopes required to make the observations. Radio telescopes for use in the low-frequency range can be built principally from ``off-the-shelf'' components. For relatively little cost for a space mission, great strides can be made in deploying arrays of antennas and receivers in space that would produce data contributing significantly to our understanding of galaxies and galactic nebulae. In this paper we discuss an evolutionary sequence of telescopes, antenna systems, receivers, and (u,v) plane coverage. The telescopes are space-based because of the disruptive aspects of the Earth's ionosphere on low-frequency celestial signals traveling to the Earth's surface. Orbiting antennas consisting of array elements deposited on a Kevlar balloon have strong advantages of nearly identical multiple beams over 4π steradians and few mechanical aspects in deployment and operation. The relatively narrow beam width of these antennas can significantly help reduce the ``confusion'' problem. The evolutionary sequence of telescopes starts with an Earth-orbiting spectrometer to measure the low-frequency radio environment in space, proceeds to a two-element interferometer, then to an orbiting array, and ends with a telescope on the lunar farside. The sequence is in the order of increasing capability which is also the order of increasing complexity and cost. All the missions can be accomplished with current technology.

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

NASA Technical Reports Server (NTRS)

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.

The Atacama Cosmology Telescope: The Polarization-Sensitive ACTPol Instrument

NASA Technical Reports Server (NTRS)

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

NASA Astrophysics Data System (ADS)

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.

Mining the Sky for Explosive Optical Transients with Both Eyes Open

NASA Astrophysics Data System (ADS)

Vestrand, W. T.; Borozdin, K.; Casperson, D. J.; Davidoff, S.; Davis, H.; Fenimore, E.; Galassi, M.; McGowan, K.; Starr, D.; White, R. R.; Wozniak, P.; Wren, J.

2004-09-01

While it has been known for centuries that the optical sky is variable, monitoring the sky for optical transients with durations as short as a minute is an area of astronomical research that remains largely unexplored. Prompt follow-up observations of Gamma Ray Bursts have shown that bright, explosive, optical transients exist. However, there are many reasons to suspect the existence of explosive optical transients that cannot be located through sky monitoring by high-energy satellites. The RAPTOR sky monitoring system is an autonomous system of telescope arrays at Los Alamos National Laboratory that identifies fast optical transients as short as a minute and makes follow-up observations in real time. The core of the RAPTOR system is composed of two arrays of telescopes, separated by 38 kilometers, that stereoscopically monitor a field of about 1300 square degrees for transients down to about 12.5th magnitude in 30 seconds. Both arrays are coupled to real-time data analysis pipelines that are designed to identify transients on timescales of seconds. Each telescope array also contains a more sensitive higher resolution ``fovea'' telescope, capable of both measuring the light curve at a faster cadence and providing color information. In a manner analogous to human vision, each array is mounted on a rapidly slewing mount so that the ``fovea'' of the array can be rapidly directed for real-time follow-up observations of any interesting transient identified by the wide-field system. We discuss the first results from RAPTOR and show that stereoscopic imaging and the absence of measurable parallax is a powerful tool for distinguishing real celestial transients in the ``forest'' of false positives.

The Allen Telescope Array

NASA Astrophysics Data System (ADS)

DeBoer, David R.; Welch, William J.; Dreher, John; Tarter, Jill; Blitz, Leo; Davis, Michael; Fleming, Matt; Bock, Douglas; Bower, Geoffrey; Lugten, John; Girmay-Keleta, G.; D'Addario, Larry R.; Harp, Gerry R.; Ackermann, Rob; Weinreb, Sander; Engargiola, Greg; Thornton, Doug; Wadefalk, Niklas

2004-10-01

The Allen Telescope Array, originally called the One Hectare Telescope (1hT) [1] will be a large array radio telescope whose novel characteristics will be a wide field of view (3.5 deg-GHz HPBW), continuous frequency coverage of 0.5 - 11 GHz, four dual-linear polarization output bands of 100 MHz each, four beams in each band, two 100 MHz spectral correlators for two of the bands, and hardware for RFI mitigation built in. Its scientific motivation is for deep SETI searches and, at the same time, a variety of other radio astronomy projects, including transient (e.g. pulsar) studies, HI mapping of the Milky Way and nearby galaxies, Zeeman studies of the galactic magnetic field in a number of transitions, mapping of long chain molecules in molecular clouds, mapping of the decrement in the cosmic background radiation toward galaxy clusters, and observation of HI absorption toward quasars at redshifts up to z=2. The array is planned for 350 6.1-meter dishes giving a physical collecting area of about 10,000 square meters. The large number of components reduces the price with economies of scale. The front end receiver is a single cryogenically cooled MIMIC Low Noise Amplifier covering the whole band. The feed is a wide-band log periodic feed of novel design, and the reflector system is an offset Gregorian for minimum sidelobes and spillover. All preliminary and critical design reviews have been completed. Three complete antennas with feeds and receivers are under test, and an array of 33 antennas is under construction at the Hat Creek Radio Observatory for the end of 2004. The present plan is to have a total of about 200 antennas completed by the summer of 2006 and the balance of the array finished before the end of the decade.

Mining the Sky for Explosive Optical Transients with Both Eyes Open

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vestrand, W.T.; Casperson, D.J.; Davis, H.

2004-09-28

While it has been known for centuries that the optical sky is variable, monitoring the sky for optical transients with durations as short as a minute is an area of astronomical research that remains largely unexplored. Prompt follow-up observations of Gamma Ray Bursts have shown that bright, explosive, optical transients exist. However, there are many reasons to suspect the existence of explosive optical transients that cannot be located through sky monitoring by high-energy satellites. The RAPTOR sky monitoring system is an autonomous system of telescope arrays at Los Alamos National Laboratory that identifies fast optical transients as short as amore » minute and makes follow-up observations in real time. The core of the RAPTOR system is composed of two arrays of telescopes, separated by 38 kilometers, that stereoscopically monitor a field of about 1300 square degrees for transients down to about 12.5th magnitude in 30 seconds. Both arrays are coupled to real-time data analysis pipelines that are designed to identify transients on timescales of seconds. Each telescope array also contains a more sensitive higher resolution 'fovea' telescope, capable of both measuring the light curve at a faster cadence and providing color information. In a manner analogous to human vision, each array is mounted on a rapidly slewing mount so that the 'fovea' of the array can be rapidly directed for real-time follow-up observations of any interesting transient identified by the wide-field system. We discuss the first results from RAPTOR and show that stereoscopic imaging and the absence of measurable parallax is a powerful tool for distinguishing real celestial transients in the 'forest' of false positives.« less

LOITA: Lunar Optical/Infrared Telescope Array

NASA Technical Reports Server (NTRS)

1993-01-01

LOITA (Lunar Optical/Infrared Telescope Array) is a lunar-based interferometer composed of 18 alt-azimuth telescopes arranged in a circular geometry. This geometry results in excellent uv coverage and allows baselines up to 5 km long. The angular resolution will be 25 micro-arcsec at 500 nm and the main spectral range of the array will be 200 to 1100 nm. For infrared planet detection, the spectral range may be extended to nearly 10 mu m. The telescope mirrors have a Cassegrain configuration using a 1.75 m diameter primary mirror and a 0.24 m diameter secondary mirror. A three-stage (coarse, intermediate, and fine) optical delay system, controlled by laser metrology, is used to equalize path lengths from different telescopes to within a few wavelengths. All instruments and the fine delay system are located within the instrument room. Upon exiting the fine delay system, all beams enter the beam combiner and are then directed to the various scientific instruments and detectors. The array instrumentation will consist of CCD detectors optimized for both the visible and infrared as well as specially designed cameras and spectrographs. For direct planet detection, a beam combiner employing achromatic nulling interferometry will be used to reduce star light (by several orders of magnitude) while passing the planet light. A single telescope will be capable of autonomous operation. This telescope will be equipped with four instruments: wide field and planetary camera, faint object camera, high resolution spectrograph, and faint object spectrograph. These instruments will be housed beneath the telescope. The array pointing and control system is designed to meet the fine pointing requirement of one micro-arcsec stability and to allow precise tracking of celestial objects for up to 12 days. During the lunar night, the optics and the detectors will be passively cooled to 70-80 K temperature. To maintain a continuous communication with the earth a relay satellite placed at the L4 libration point will be used in conjunction with the Advanced Tracking and Data Relay Satellite System (ATDRSS). Electrical power of about 10 kW will be supplied by a nuclear reactor based on the SP-100 technology. LOITA will be constructed in three phases of six telescopes each. The total mass of the first operational phase is estimated at 58,820 kg. The cost of the fully operational first phase of the observatory is estimated at $8.9 billion. LOITA's primary objectives will be to detect and characterize planets around nearby stars (up to ten parsec away), study physics of collapsed stellar objects, solar/stellar surface features and the processes in nuclear regions of galaxies and quasars. An interferometric array such as LOITA will be capable of achieving resolutions three orders of magnitude greater than Hubble's design goal. LOITA will also be able to maintain higher signal to noise ratios than are currently attainable due to long observation times available on the moon.

Ghostly Boomerang

NASA Image and Video Library

2013-10-25

The Boomerang nebula, called the coldest place in the universe, reveals its true shape to the Atacama Large Millimeter/submillimeter Array ALMA telescope. The background blue structure, is seen in visible light by NASA Hubble Space Telescope.

Recent Results of the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Ivanov, Dmitri

2015-04-01

The Telescope Array (TA) is the largest cosmic ray experiment in the northern hemisphere and covers 10 PeV to 100 EeV range. TA is a hybrid detector that uses air fluorescence detectors combined with a ground array. TA consists of 507 plastic scintillation counters on a 1.2km square grid, overlooked by 3 fluorescence detector stations, and measures cosmic rays above 1 EeV. TA has collected 6.5 years of data. Results from the TA low energy extension (TALE), which sees cosmic rays down to 10 PeV, will also be shown. This contribution will consist of three parts. First, we will present the cosmic ray energy spectrum measured over 4 decades in energy. Next, we will discuss the latest results of the measurements of cosmic ray mass composition by the TA fluorescence detectors. Finally, we will show the latest results of the TA anisotropy measurements at the highest energies, where we have seen a concentration of events, called the ``hotspot,'' centered in the Ursa Major. For the Telescope Array Collaboration. Done...processed 1261 records...10:46:59 Beginning APS data extraction...10:47:48

A Unique test for Hubble's new Solar Arrays

NASA Astrophysics Data System (ADS)

2000-10-01

In mid-October, a team from the European Space Agency (ESA) and NASA will perform a difficult, never-before-done test on one of the Hubble Space Telescope's new solar array panels. Two of these panels, or arrays, will be installed by astronauts in November 2001, when the Space Shuttle Columbia visits Hubble on a routine service mission. The test will ensure that the new arrays are solid and vibration free before they are installed on orbit. The test will be conducted at ESA's European Space Research and Technology Center (ESTEC) in Noordwijk, The Netherlands. Because of the array's size, the facility's special features, and ESA's longstanding experience with Hubble's solar arrays, ESTEC is the only place in the world the test can be performed. This test is the latest chapter in a longstanding partnership between ESA and NASA on the Hubble Space Telescope. The Large Space Simulator at ESTEC, ESA's world-class test facility, features a huge vacuum chamber containing a bank of extremely bright lights that simulate the Sun's intensity - including sunrise and sunset. By exposing the solar wing to the light and temperature extremes of Hubble's orbit, engineers can verify how the new set of arrays will act in space. Hubble orbits the Earth once every 90 minutes. During each orbit, the telescope experiences 45 minutes of searing sunlight and 45 minutes of frigid darkness. This test will detect any tiny vibrations, or jitters, caused by these dramatic, repeated changes. Even a small amount of jitter can affect Hubble's sensitive instruments and interfere with observations. Hubble's first set of solar arrays experienced mild jitter and was replaced in 1993 with a much more stable pair. Since that time, advances in solar cell technology have led to the development of even more efficient arrays. In 2001, NASA will take advantage of these improvements, by fitting Hubble with a third-generation set of arrays. Though smaller, this new set generates more power than the previous pairs. The arrays use high efficiency solar cells and an advanced structural system to support the solar panels. Unlike the earlier sets, which roll up like window shades, the new arrays are rigid. ESA provided Hubble's first two sets of solar arrays, and built and tested the motors and electronics of the new set provided by NASA Goddard Space Flight Center. Now, this NASA/ESA test has benefits that extend beyond Hubble to the world-wide aerospace community. It will greatly expand basic knowledge of the jitter phenomenon. Engineers across the globe can apply these findings to other spacecraft that are subjected to regular, dramatic changes in sunlight and temperature. Note to editors The Hubble Project The Hubble Space Telescope is a project of international co-operation between the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The partnership agreement between ESA and NASA was signed on 7 October 1977. ESA has provided two pairs of solar panels and one of Hubble's scientific instruments (the Faint Object Camera), as well as a number of other components and supports NASA during routine Servicing Missions to the telescope. In addition, 15 European scientists are working at the Space Telescope Science Institute in Baltimore (STScI), which is responsible for the scientific operation of the Hubble Observatory and is managed by the Association of Universities for Research in Astronomy (AURA) for NASA. In return, European astronomers have guaranteed access to 15% of Hubble's observing time. The Space Telescope European Coordinating Facility (ST-ECF) hosted at the European Southern Observatory (ESO) in Garching bei München, Germany, supports European Hubble users. ESA and ESO jointly operate the ST-ECF.

NIFTE: The Near Infrared Faint-Object Telescope Experiment

NASA Technical Reports Server (NTRS)

Bock, James J.; Lange, Andrew E.; Matsumoto, T.; Eisenhardt, Peter B.; Hacking, Perry B.; Schember, Helene R.

1994-01-01

The high sensitivity of large format InSb arrays can be used to obtain deep images of the sky at 3-5 micrometers. In this spectral range cool or highly redshifted objects (e.g. brown dwarfs and protogalaxies) which are not visible at shorter wavelengths may be observed. Sensitivity at these wavelengths in ground-based observations is severly limited by the thermal flux from the telescope and from the earth's atmosphere. The Near Infrared Faint-Object Telescope Experiment (NIFTE), a 50 cm cooled rocket-borne telescope combined with large format, high performance InSb arrays, can reach a limiting flux less than 1 micro-Jy(1-sigma) over a large field-of-view in a single flight. In comparison, the Infrared Space Observatory (ISO) will require days of observation to reach a sensitivity more than one order of magnitude worse over a similar area of the sky. The deep 3-5 micrometer images obtained by the rocket-borne telescope will assist in determining the nature of faint red objects detected by ground-based telescopes at 2 micrometers, and by ISO at wavelengths longer than 5 micrometers.

Fish-Eye Observing with Phased Array Radio Telescopes

NASA Astrophysics Data System (ADS)

Wijnholds, S. J.

The radio astronomical community is currently developing and building several new radio telescopes based on phased array technology. These telescopes provide a large field-of-view, that may in principle span a full hemisphere. This makes calibration and imaging very challenging tasks due to the complex source structures and direction dependent radio wave propagation effects. In this thesis, calibration and imaging methods are developed based on least squares estimation of instrument and source parameters. Monte Carlo simulations and actual observations with several prototype show that this model based approach provides statistically and computationally efficient solutions. The error analysis provides a rigorous mathematical framework to assess the imaging performance of current and future radio telescopes in terms of the effective noise, which is the combined effect of propagated calibration errors, noise in the data and source confusion.

Design and Expected Performance of GISMO-2, a Two Color Millimeter Camera for the IRAM 30 m Telescope

NASA Technical Reports Server (NTRS)

Staguhn, Johannes G.; Benford, Dominic J.; Dwek, Eli; Hilton, Gene; Fixsen, Dale J.; Irwin, Kent; Jhabvala, Christine; Kovacs, Attila; Leclercq, Samuel; Maher, Stephen F.;

Features of the solar array drive mechanism for the space telescope

NASA Technical Reports Server (NTRS)

Hostenkamp, R. G.

1985-01-01

The solar array drive mechanism for the Space Telescope embodies several features not customarily found on solar array drives. Power and signal transfer is achieved by means of a flexible wire harness for which the chosen solution, consisting of 168 standard wires, is described. The torque performance data of the harness over its temperature range are presented. The off load system which protects the bearings from the launch loads is released by a trigger made from Nitinol, the memory alloy. The benefits of memory alloy and the caveats for the design are briefly discussed. The design of the off load system is described and test experience is reported.

Gamma--Ray burst afterglows with the Watcher robotic telescope

NASA Astrophysics Data System (ADS)

Topinka, M.; Hanlon, L.; Meehan, S.; Tisdall, P.; Jelínek, M.; Kubánek, P.; van Heerden, H.; Meintjes, P.

2014-12-01

The main scientific goal of the Watcher robotic telescope is the rapid follow-up observation of gamma--ray burst afterglows. Some examples of recent observations, including GRB 120327A and GRB 130606A, at a redshift of 5.9, are presented. The telescope has recently been successfully integrated into the GLORIA global robotic telescope network, which allows users to use the array for their own scientific projects.

STS-31 Hubble Space Telescope (HST) solar array panel deploy aboard OV-103

NASA Image and Video Library

1990-04-25

Held in appendage deploy position by Discovery's, Orbiter Vehicle (OV) 103's, remote manipulator system (RMS), the Hubble Space Telescope's (HST's) starboard solar array (SA) bistem cassette is released from its stowed position on the Support System Module (SSM) forward shell. The spreader bar & bistem begin to unfurl the SA wing. View was taken by an STS-31 crewmember through an overhead window & is backdropped against the surface of the Earth.

Thermal/Dynamic Characterization Test of the Solar Array Panel for Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Jenkins, Kathleen; Hershfeld, Donald J.

1999-01-01

The Hubble Space Telescope has experienced a problem maintaining pointing accuracy during emergence of the spacecraft from the Earth's shadow. The problem has been attributed to the rapid thermal gradient that develops when the heat from the Sun strikes the cold solar arrays. The thermal gradient causes the solar arrays to deflect or bend and this motion is sufficient to disturb the pointing control system. In order to alleviate this problem, a new design for the solar arrays has been fabricated. These new solar arrays will replace the current solar arrays during a future Hubble servicing mission. The new solar arrays have been designed so that the effective net motion of the center of mass of each panel is essentially zero. Although the solar array thermal deflection problem has been studied extensively over a period of years, a full scale test of the actual flight panels was required in order to establish confidence in the analyses. This test was conducted in the JPL Solar Simulation Facility in April, 1999. This presentation will discuss the objectives and methods of the test and present some typical test data.

Telescoping Solar Array Concept for Achieving High Packaging Efficiency

NASA Technical Reports Server (NTRS)

Mikulas, Martin; Pappa, Richard; Warren, Jay; Rose, Geoff

2015-01-01

Lightweight, high-efficiency solar arrays are required for future deep space missions using high-power Solar Electric Propulsion (SEP). Structural performance metrics for state-of-the art 30-50 kW flexible blanket arrays recently demonstrated in ground tests are approximately 40 kW/cu m packaging efficiency, 150 W/kg specific power, 0.1 Hz deployed stiffness, and 0.2 g deployed strength. Much larger arrays with up to a megawatt or more of power and improved packaging and specific power are of interest to mission planners for minimizing launch and life cycle costs of Mars exploration. A new concept referred to as the Compact Telescoping Array (CTA) with 60 kW/cu m packaging efficiency at 1 MW of power is described herein. Performance metrics as a function of array size and corresponding power level are derived analytically and validated by finite element analysis. Feasible CTA packaging and deployment approaches are also described. The CTA was developed, in part, to serve as a NASA reference solar array concept against which other proposed designs of 50-1000 kW arrays for future high-power SEP missions could be compared.

Development of Infrared Phase Closure Capability in the Infrared-Optical Telescope Array (IOTA)

NASA Technical Reports Server (NTRS)

Traub, Wesley A.

2002-01-01

We completed all major fabrication and testing for the third telescope and phase-closure operation at the Infrared-Optical Telescope Array (IOTA) during this period. In particular we successfully tested the phase-closure operation, using a laboratory light source illuminating the full delay-line optical paths, and using an integrated-optic beam combiner coupled to our Picnic-detector camera. This demonstration is an important and near-final milestone achievement. As of this writing, however, several tasks yet remain, owing to development snags and weather, so the final proof of success, phase-closure observation of a star, is now expected to occur in early 2002, soon after this report has been submitted.

Overview 1993: Computational applications

NASA Technical Reports Server (NTRS)

Benek, John A.

1993-01-01

Computational applications include projects that apply or develop computationally intensive computer programs. Such programs typically require supercomputers to obtain solutions in a timely fashion. This report describes two CSTAR projects involving Computational Fluid Dynamics (CFD) technology. The first, the Parallel Processing Initiative, is a joint development effort and the second, the Chimera Technology Development, is a transfer of government developed technology to American industry.

Advanced Hydrocarbon Fuel Development

NASA Technical Reports Server (NTRS)

Bai, S. Don; Rodgers, Stephen L. (Technical Monitor)

2000-01-01

As a part of a high energy density materials (HEDM) development, the hot fire tests for Quadricyclane, 1,7 Octadiyne, AFRL-1, Biclopropylidene, and CINCH (Dimethyl amino ethyl azide) have been conducted at NASA/MSFC. The first 4 materials for this task are provided from Air Force Research Laboratory at Edward Air Force Base and US Army provided CINCH. The performance of these fuels is compared with RP-1. The preliminary results of these tests are presented. The preliminary results of Quadricyclane tests indicate that the specific impulse and c-star efficiency for quadricyclane at the mixture ratio 1.94 are approximately 5 sec and 105 ft/sec better than the RP-1 at mixture ratio 1.9. The 1,7 Octadiyne test indicate that the specific impulse and c-star efficiency at the mixture ratio 2.1 are approximately -1 sec and 89 ft/sec differ than the RP-1 at mixture ratio 2.04. The Quadricyclane soot buildup at the combustor is a little more than RP-1, but detail study of soot formation is not considered at this time. There was no visual soot buildup for the 1,7 Octadiyne and AFRL-1.

Microshutter Array Development for the Multi-Object Spectrograph for the New Generation Space Telescope, and Its Ground-based Demonstrator

NASA Technical Reports Server (NTRS)

Woodgate, Bruce E.; Moseley, Harvey; Fettig, Rainer; Kutyrev, Alexander; Ge, Jian; Fisher, Richard R. (Technical Monitor)

2001-01-01

The 6.5-m NASA/ESA/Canada New Generation Space Telescope to be operated at the L2 Lagrangian point will require a multi-object spectrograph (MOS) operating from 1 to 5 microns. Up to 3000 targets will be selected for simultaneous spectroscopy using a programmable cryogenic (approx. 35K) aperture array, consisting of a mosaic of arrays of micromirrors or microshutters. We describe the current status of the GSFC microshutter array development. The 100 micron square shutters are opened magnetically and latched open or closed electrostatically. Selection will be by two crossed one-dimensional addressing circuits. We will demonstrate the use of a 512 x 512 unit array on a ground-based IR MOS which will cover 0.6 to 5 microns, and operate rapidly to include spectroscopy of gamma ray burst afterglows.

Initial astronomical results with a new 5-14 micron Si:Ga 58x62 DRO array camera

NASA Technical Reports Server (NTRS)

Gezari, Dan; Folz, Walter; Woods, Larry

1989-01-01

A new array camera system was developed using a 58 x 62 pixel Si:Ga (gallium doped silicon) DRO (direct readout) photoconductor array detector manufactured by Hughes/Santa Barbara Research Center (SBRC). The camera system is a broad band photometer designed for 5 to 14 micron imaging with large ground-based optical telescopes. In a typical application a 10 micron photon flux of about 10(exp 9) photons sec(exp -1) m(exp -2) microns(exp -1) arcsec(exp -2) is incident in the telescope focal plane, while the detector well capacity of these arrays is 10(exp 5) to 10 (exp 6) electrons. However, when the real efficiencies and operating conditions are accounted for, the 2-channel 3596 pixel array operates with about 1/2 full wells at 10 micron and 10% bandwidth with high duty cycle and no real experimental compromises.

Mechanical Designs and Developement of Advanced ACT: A Transfomative Upgrade to the ACTPol Receiver on the Atacama Cosmology Telescope.

NASA Astrophysics Data System (ADS)

Ward, Jonathan; Advanced ACT Collaboration, NASA Space Technology Research Fellowship

2017-06-01

The Atacama Cosmology Telescope is a six-meter diameter telescope located at 17,000 feet (5,200 meters) on Cerro Toco in the Andes Mountains of northern Chile. The next generation Advanced ACT (AdvACT) experiment is currently underway and will consist of three multichroic TES bolometer arrays operating together, totaling 5800 detectors on the sky. Each array will be sensitive to two frequency bands: a high frequency (HF) array at 150 and 230 GHz, two middle frequency (MF) arrays at 90 and 150 GHz, and a low frequency (LF) array at 28 and 41 GHz. The AdACT detector arrays will feature a revamped design when compared to ACTPol, including a transition to 150mm wafers equipped with multichroic pixels, allowing for a more densely packed focal plane. Each set of detectors consists of a feedhorn array of stacked silicon wafers which form a corrugated profile leading to each pixel. This is then followed by a four-piece detector stack assembly of silicon wafers which includes a waveguide interface plate, detector wafer, backshort cavity plate, and backshort cap. Each array is housed in a custom designed structure manufactured out of gold-plated, high purity copper. In addition to the detector array assembly, the array package also encloses the majority of our readout electronics. We present the full mechanical design of the AdvACT HF and MF detector array packages along with a detailed look at the detector array assemblies. We also highlight the use of continuously rotating warm half-wave plates (HWPs) at the front of the AdvACT receiver. We review the design of the rotation system and also early pipeline data analysis results. This experiment will also make use of extensive hardware and software previously developed for ACT, which will be modified to incorporate the new AdvACT instruments. Therefore, we discuss the integration of all AdvACT instruments with pre-existing ACTPol infrastructure.

Assessment study of infrared detector arrays for low-background astronomical research

NASA Technical Reports Server (NTRS)

Ando, K. J.

1978-01-01

The current state-of-the-art of infrared detector arrays employing charge coupled devices (CCD) or charge injection devices (CID) readout are assessed. The applicability, limitations and potentials of such arrays under the low-background astronomical observing conditions of interest for SIRFT (Shuttle Infrared Telescope Facility) are determined. The following are reviewed: (1) monolithic extrinsic arrays; (2) monolithic intrinsic arrays; (3) charge injection devices; and (4) hybrid arrays.

Science with the ASTRI mini-array for the Cherenkov Telescope Array: blazars and fundamental physics

NASA Astrophysics Data System (ADS)

Bonnoli, Giacomo; Tavecchio, Fabrizio; Giuliani, Andrea; Bigongiari, Ciro; Di Pierro, Federico; Stamerra, Antonio; Pareschi, Giovanni; Vercellone, Stefano; ASTRI Collaboration; CTA Consortium

2016-05-01

ASTRI (“Astronomia a Specchi con Tecnologia Replicante Italiana”) is a flagship project of the Italian Ministry of Research (MIUR), devoted to the realization, operation and scientific validation of an end-to-end prototype for the Small Size Telescope (SST) envisaged to become part of the Cherenkov Telescope Array (CTA). The ASTRI SST-2M telescope prototype is characterized by a dual mirror, Schwarzschild-Couder optical design and a compact camera based on silicon photo-multipliers. It will be sensitive to multi-TeV very high energy (VHE) gamma rays up to 100 TeV, with a PSF ~ 6’ and a wide (9.6°) unaberrated optical field of view. Right after validation of the design in single-dish observations at the Serra La Nave site (Sicily, Italy) during 2015, the ASTRI collaboration will be able to start deployment, at the final CTA southern site, of the ASTRI mini-array, proposed to constitute the very first CTA precursor. Counting 9 ASTRI SST-2M telescopes, the ASTRI mini-array will overtake current IACT systems in differential sensitivity above 5 TeV, thus allowing unprecedented observations of known and predicted bright TeV emitters in this band, including some extragalactic sources such as extreme high-peaked BL Lacs with hard spectra. We exploited the ASTRI scientific simulator ASTRIsim in order to understand the feasibility of observations tackling blazar and cosmic ray physics, including discrimination of hadronic and leptonic scenarios for the VHE emission from BL Lac relativistic jets and indirect measurements of the intergalactic magnetic field and of the extragalactic background light. We selected favorable targets, outlining observation modes, exposure times, multi-wavelength coverage needed and the results expected. Moreover, the perspectives for observation of effects due to the existence of axion-like particles or to Lorentz invariance violations have been investigated.

New electronics for the Cherenkov Telescope Array (NECTAr)

NASA Astrophysics Data System (ADS)

Naumann, C. L.; Delagnes, E.; Bolmont, J.; Corona, P.; Dzahini, D.; Feinstein, F.; Gascón, D.; Glicenstein, J.-F.; Guilloux, F.; Nayman, P.; Rarbi, F.; Sanuy, A.; Tavernet, J.-P.; Toussenel, F.; Vincent, P.; Vorobiov, S.

2012-12-01

The international CTA consortium has recently entered into its preparatory phase towards the construction of the next-generation Cherenkov Telescope Array CTA. This experiment will be a successor, and based on the return of experience from the three major current-generation arrays H.E.S.S., MAGIC and VERITAS, and aims to significantly improve upon the sensitivity as well as the energy range of its highly successful predecessors. Construction is planned to begin by 2013, and when finished, CTA will be able to explore the highest-energy gamma ray sky in unprecedented detail. To achieve this increase in sensitivity and energy range, CTA will employ the order of 100 telescopes of three different sizes on two sites, with around 1000-4000 channels per camera, depending on the telescope size. To equip and reliably operate the order of 100000 channels of photodetectors (compared to 6000 of the H.E.S.S. array), a new kind of flexible and powerful yet inexpensive front-end hardware will be required. One possible solution is pursued by the NECTAr (New Electronics for the Cherenkov Telescope Array) project. Its main feature is the integration of as much as possible of the front-end electronics (amplifiers, fast analogue samplers, memory and ADCs) into a single ASIC, which will allow very fast readout performances while significantly reducing the cost and the power consumption per channel. Also included is a low-cost FPGA for digital treatment and online data processing, as well as an Ethernet connection. Other priorities of NECTAr are the modularity of the system, a high degree of flexibility in the trigger system as well as the possibility of flexible readout modes to optimise the signal-to-noise ratio while at the same time allowing a significant reduction of data rates, both of which could improve the sensitivity of CTA compared to current detection systems. This paper gives an overview over the development work for the Nectar system, with particular focus on its main component, the NECTAr ASIC.

Kilopixel Pop-Up Bolometer Arrays for the Atacama Cosmology Telescope

NASA Technical Reports Server (NTRS)

Chervenak, J. A.; Wollack, E.; Henry, R.; Moseley, S. H.; Niemack, M.; Staggs, S.; Page, L.; Doriese, R.; Hilton, G. c.; Irwin, K. D.

2007-01-01

The recently deployed Atacama Cosmology Telescope (ACT) anticipates first light on its kilopixel array of close-packed transition-edge-sensor bolometers in November of 2007. The instrument will represent a full implementation of the next-generation, large format arrays for millimeter wave astronomy that use superconducting electronics and detectors. Achieving the practical construction of such an array is a significant step toward producing advanced detector arrays for future SOFIA instruments. We review the design considerations for the detector array produced for the ACT instrument. The first light imager consists of 32 separately instrumented 32-channel pop-up bolometer arrays (to create a 32x32 filled array of mm-wave sensors). Each array is instrumented with a 32-channel bias resistor array, Nyquist filter array, and time-division SQUID multiplexer. Each component needed to be produced in relatively large quantities with suitable uniformity to meet tolerances for array operation. An optical design was chosen to maximize absorption at the focal plane while mitigating reflections and stray light. The pop-up geometry (previously implemented with semiconducting detectors and readout on the SHARC II and HAWC instruments) enabled straightforward interface of the superconducting bias and readout circuit with the 2D array of superconducting bolometers. The array construction program balanced fabrication challenges with assembly challenges to deliver the instrument in a timely fashion. We present some of the results of the array build and characterization of its performance.

Testing light concentrators prototypes for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Hénault, François; Petrucci, Pierre-Olivier; Jocou, Laurent; Arezki, Brahim; Magnard, Yves; Khélifi, Bruno; Manigot, Pascal; Olive, Jean-François; Jean, Pierre; Punch, Michael

2017-09-01

With more than 30 Medium-Size Telescopes (MST) located in both North and South hemispheres, the Cherenkov Telescope Array (CTA) shall be the largest cosmic gamma ray detector ever built. Each MST focal plane consists in an array of some 1800 photomultipliers equipped with their own light concentrating optics in order to maximizing the amount of Cherenkov radiation collected by the telescope and to block stray light originating from ground environment. Within the CTA Consortium, the Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) is in charge of designing, subcontracting the realization to industry, and testing the MST light concentrators. Two different optical solutions were pre-selected, respectively based on CPCs (Winston cones) and non-imaging concentrating lenses. Prototypes were manufactured by different industrial companies and tested in our laboratory on a test bench specifically built for the project. After shortly describing both optical designs, this communication is essentially focused at experimental results. Each type of concentrator has been submitted to extensive performance measurements, including radiometric efficiency at different wavelengths, rejection curves, and qualitative shape error test. The final selected concentrator is the CPC, although non-imaging lenses exhibit interesting properties in terms of radiometric performance.

H.E.S.S. and CTA, present and perspectives in ground-based gamma-ray astronomy

NASA Astrophysics Data System (ADS)

Sol, H.

2016-12-01

Very high energy (VHE) gamma-ray astronomy emerged as a new branch of astronomy about ten years ago with the major discoveries achieved by the High Energy Stereocopic System (H.E.S.S.) operating in Namibia, quickly followed by the Major Atmospheric Gamma Imaging Cherenkov Telescopes (MAGIC) in the Canary Islands and the Very Energetic Radiation Imaging Telescope Array System (VERITAS) in the USA. These experiments succeeded to start exploring the cosmos at TeV energies, with the present detection of 178 sources in this range, mostly pulsar wind nebulae, supernova remnants, binary systems, blazars, and a variety of other types of sources. Based on these promizing results, the scientific community soon defined a next generation global project with significantly improved performance, the Cherenkov Telescope Array (CTA), in order to implement an open observatory at extreme energies, allowing a deep analysis of the sky in the highest part of the electromagnetic spectrum, from 20 GeV to 300 TeV. The CTA preparation phase is now completed. Production of the first telescopes should start in 2017 for deployment in 2018, in the perspective of an array fully operational at the horizon 2022.

The Atmospheric Monitoring Strategy for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Daniel, M. K.; CTA Consortium

2015-04-01

The Imaging Atmospheric Cherenkov Technique (IACT) is unusual in astronomy as the atmosphere actually forms an intrinsic part of the detector system, with telescopes indirectly detecting very high energy particles by the generation and transport of Cherenkov photons deep within the atmosphere. This means that accurate measurement, characterisation and monitoring of the atmosphere is at the very heart of successfully operating an IACT system. The Cherenkov Telescope Array (CTA) will be the next generation IACT observatory with an ambitious aim to improve the sensitivity of an order of magnitude over current facilities, along with corresponding improvements in angular and energy resolution and extended energy coverage, through an array of Large (23 m), Medium (12 m) and Small (4 m) sized telescopes spread over an area of order ~km2. Whole sky coverage will be achieved by operating at two sites: one in the northern hemisphere and one in the southern hemisphere. This proceedings will cover the characterisation of the candidate sites and the atmospheric calibration strategy. CTA will utilise a suite of instrumentation and analysis techniques for atmospheric modelling and monitoring regarding pointing forecasts, intelligent pointing selection for the observatory operations and for offline data correction.

The Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Otte, Nepomuk

The Advanced Gamma-ray Imaging System (AGIS) is a concept for the next generation of imag-ing atmospheric Cherenkov telescope arrays. It has the goal of providing an order of magnitude increase in sensitivity for Very High Energy Gamma-ray ( 100 GeV to 100 TeV) astronomy compared to currently operating arrays such as CANGAROO, HESS, MAGIC, and VERITAS. After an overview of the science such an array would enable, we discuss the development of the components of the telescope system that are required to achieve the sensitivity goal. AGIS stresses improvements in several areas of IACT technology including component reliability as well as exploring cost reduction possibilities in order to achieve its goal. We discuss alterna-tives for the telescopes and positioners: a novel Schwarzschild-Couder telescope offering a wide field of view with a relatively smaller plate scale, and possibilities for rapid slewing in order to address the search for and/or study of Gamma-ray Bursts in the VHE gamma-ray regime. We also discuss options for a high pixel count camera system providing the necessary finer solid angle per pixel and possibilities for a fast topological trigger that would offer improved realtime background rejection and lower energy thresholds.

Life Cycle Testing of Viscoelastic Material for Hubble Space Telescope Solar Array 3 Damper

NASA Technical Reports Server (NTRS)

Maly, Joseph R.; Reed, Benjamin B.; Viens, Michael J.; Parker, Bradford H.; Pendleton, Scott C.

2003-01-01

During the March 2002 Servicing Mission by Space Shuttle (STS 109), the Hubble Space Telescope (HST) was refurbished with two new solar arrays that now provide all of its power. These arrays were built with viscoelastic/titanium dampers, integral to the supporting masts, which reduce the interaction of the wing bending modes with the Telescope. Damping of over 3% of critical was achieved. To assess the damper s ability to maintain nominal performance over the 10-year on-orbit design goal, material specimens were subjected to an accelerated life test. The test matrix consisted of scheduled events to expose the specimens to pre-determined combinations of temperatures, frequencies, displacement levels, and numbers of cycles. These exposure events were designed to replicate the life environment of the damper from fabrication through testing to launch and life on-orbit. To determine whether material degradation occurred during the exposure sequence, material performance was evaluated before and after the accelerated aging with complex stiffness measurements. Based on comparison of pre- and post-life-cycle measurements, the material is expected to maintain nominal performance through end of life on-orbit. Recent telemetry from the Telescope indicates that the dampers are performing nominally.

STS-109 MS Grunsfeld and Linnehan stow old solar array from payload bay

NASA Image and Video Library

2002-03-04

STS109-E-5244 (4 March 2002) --- Astronauts John M. Grunsfeld (red stripes on suit), payload commander, and Richard M. (Rick) Linnehan, mission specialist, participate in the first of their assigned STS-109 space walks to perform work on the Hubble Space Telescope (HST). The two went on to replace the giant telescope’s starboard solar array. Their seven-hour space walk ended at 7:38 a.m. (CST) or 13:38 GMT March 4, 2002.

Simulation based evaluation of the designs of the Advanced Gamma-ray Imageing System (AGIS)

NASA Astrophysics Data System (ADS)

Bugaev, Slava; Buckley, James; Digel, Seth; Funk, Stephen; Konopelko, Alex; Krawczynski, Henric; Lebohec, Steohan; Maier, Gernot; Vassiliev, Vladimir

2009-05-01

The AGIS project under design study, is a large array of imaging atmospheric Cherenkov telescopes for gamma-rays astronomy between 40GeV and 100 TeV. In this paper we present the ongoing simulation effort to model the considered design approaches as a function of the main parameters such as array geometry, telescope optics and camera design in such a way the gamma ray observation capabilities can be optimized against the overall project cost.

Photogrammetric Assessment of the Hubble Space Telescope Solar Arrays During the Second Servicing Mission

NASA Technical Reports Server (NTRS)

Sapp, C. A.; Dragg, J. L.; Snyder, M. W.; Gaunce, M. T.; Decker, J. E.

1998-01-01

This report documents the photogrammetric assessment of the Hubble Space Telescope (HST) solar arrays conducted by the NASA c Center Image Science and Analysis Group during Second Servicing Mission 2 (SM-2) on STS-82 in February 1997. Two type solar array analyses were conducted during the mission using Space Shuttle payload bay video: (1) measurement of solar array motion due to induced loads, and (2) measurement of the solar array static or geometric twist caused by the cumulative array loading. The report describes pre-mission planning and analysis technique development activities conducted to acquire and analyze solar array imagery data during SM-2. This includes analysis of array motion obtained during SM-1 as a proof-of-concept of the SM-2 measurement techniques. The report documents the results of real-time analysis conducted during the mission and subsequent analysis conducted post-flight. This report also provides a summary of lessons learned on solar array imagery analysis from SM-2 and recommendations for future on-orbit measurements applicable to HST SM-3 and to the International Space Station. This work was performed under the direction of the Goddard Space Flight Center HST Flight Systems and Servicing Project.

Obscura telescope with a MEMS micromirror array for space observation of transient luminous phenomena or fast-moving objects.

PubMed

Park, J H; Garipov, G K; Jeon, J A; Khrenov, B A; Kim, J E; Kim, M; Kim, Y K; Lee, C-H; Lee, J; Na, G W; Nam, S; Park, I H; Park, Y-S

2008-12-08

We introduce a novel telescope consisting of a pinhole-like camera with rotatable MEMS micromirrors substituting for pinholes. The design is ideal for observations of transient luminous phenomena or fast-moving objects, such as upper atmospheric lightning and bright gamma ray bursts. The advantage of the MEMS "obscura telescope" over conventional cameras is that it is capable both of searching for events over a wide field of view, and fast zooming to allow detailed investigation of the structure of events. It is also able to track the triggering object to investigate its space-time development, and to center the interesting portion of the image on the photodetector array. We present the proposed system and the test results for the MEMS obscura telescope which has a field of view of 11.3 degrees, sixteen times zoom-in and tracking within 1 ms. (c) 2008 Optical Society of America

The ASTRI SST-2M telescope prototype for the Cherenkov Telescope Array: camera DAQ software architecture

NASA Astrophysics Data System (ADS)

Conforti, Vito; Trifoglio, Massimo; Bulgarelli, Andrea; Gianotti, Fulvio; Fioretti, Valentina; Tacchini, Alessandro; Zoli, Andrea; Malaguti, Giuseppe; Capalbi, Milvia; Catalano, Osvaldo

2014-07-01

ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project financed by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. Within this framework, INAF is currently developing an end-to-end prototype of a Small Size dual-mirror Telescope. In a second phase the ASTRI project foresees the installation of the first elements of the array at CTA southern site, a mini-array of 7 telescopes. The ASTRI Camera DAQ Software is aimed at the Camera data acquisition, storage and display during Camera development as well as during commissioning and operations on the ASTRI SST-2M telescope prototype that will operate at the INAF observing station located at Serra La Nave on the Mount Etna (Sicily). The Camera DAQ configuration and operations will be sequenced either through local operator commands or through remote commands received from the Instrument Controller System that commands and controls the Camera. The Camera DAQ software will acquire data packets through a direct one-way socket connection with the Camera Back End Electronics. In near real time, the data will be stored in both raw and FITS format. The DAQ Quick Look component will allow the operator to display in near real time the Camera data packets. We are developing the DAQ software adopting the iterative and incremental model in order to maximize the software reuse and to implement a system which is easily adaptable to changes. This contribution presents the Camera DAQ Software architecture with particular emphasis on its potential reuse for the ASTRI/CTA mini-array.

ICE: A Scalable, Low-Cost FPGA-Based Telescope Signal Processing and Networking System

NASA Astrophysics Data System (ADS)

Bandura, K.; Bender, A. N.; Cliche, J. F.; de Haan, T.; Dobbs, M. A.; Gilbert, A. J.; Griffin, S.; Hsyu, G.; Ittah, D.; Parra, J. Mena; Montgomery, J.; Pinsonneault-Marotte, T.; Siegel, S.; Smecher, G.; Tang, Q. Y.; Vanderlinde, K.; Whitehorn, N.

2016-03-01

We present an overview of the ‘ICE’ hardware and software framework that implements large arrays of interconnected field-programmable gate array (FPGA)-based data acquisition, signal processing and networking nodes economically. The system was conceived for application to radio, millimeter and sub-millimeter telescope readout systems that have requirements beyond typical off-the-shelf processing systems, such as careful control of interference signals produced by the digital electronics, and clocking of all elements in the system from a single precise observatory-derived oscillator. A new generation of telescopes operating at these frequency bands and designed with a vastly increased emphasis on digital signal processing to support their detector multiplexing technology or high-bandwidth correlators — data rates exceeding a terabyte per second — are becoming common. The ICE system is built around a custom FPGA motherboard that makes use of an Xilinx Kintex-7 FPGA and ARM-based co-processor. The system is specialized for specific applications through software, firmware and custom mezzanine daughter boards that interface to the FPGA through the industry-standard FPGA mezzanine card (FMC) specifications. For high density applications, the motherboards are packaged in 16-slot crates with ICE backplanes that implement a low-cost passive full-mesh network between the motherboards in a crate, allow high bandwidth interconnection between crates and enable data offload to a computer cluster. A Python-based control software library automatically detects and operates the hardware in the array. Examples of specific telescope applications of the ICE framework are presented, namely the frequency-multiplexed bolometer readout systems used for the South Pole Telescope (SPT) and Simons Array and the digitizer, F-engine, and networking engine for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) radio interferometers.

Observation management challenges of the Square Kilometre Array

NASA Astrophysics Data System (ADS)

Bridger, Alan; Williams, Stewart J.; Nicol, Mark; Klaassen, Pamela; Thompson, Roger S.; Knapic, Cristina; Jerse, Giovanna; Orlati, Andrea; Messina, Marco; Valame, Snehal

2016-07-01

The Square Kilometre Array (SKA) will be the world's most advanced radio telescope, designed to explore some of the biggest questions in astronomy today, such as the epoch of re-ionization, the nature of gravity and the origins of cosmic magnetism. SKA1, the first phase of SKA construction, is currently being designed by a large team of experts world-wide. SKA1 comprises two telescopes: a 200-element dish interferometer in South Africa and a 130000-element dipole antenna aperture array in Australia. To enable the ground-breaking science of the SKA an advanced Observation Management system is required to support both the needs of the astronomical community users and the SKA Observatory staff. This system will ensure that the SKA realises its scientiffc aims and achieves optimal scientific throughput. This paper provides an overview of the design of the system that will accept proposals from SKA users, and result in the execution of the scripts that will obtain science data, taking in the stages of detailed preparation, planning and scheduling of the observations and onwards tracking. It describes the unique challenges of the differing requirements of two telescopes, one of which is very much a software telescope, including the need to schedule the data processing as well as the acquisition, and to react to both internally and externally discovered transient events. The scheduling of multiple parallel sub-array use is covered, along with the need to handle commensal observing - using the same data stream to satisfy the science goals of more than one project simultaneously. An international team from academia and industry, drawing on expertise and experience from previous telescope projects, the virtual observatory and comparable problems in industry, has been assembled to design the solution to this challenging but exciting problem.

The Atacama Cosmology Telescope: The Polarization-Sensitive ACTPol Instrument

DOE PAGES

Thornton, R. J.; Ade, P. A. R.; Aiola, S.; ...

2016-12-09

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 thermalmore » 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.« less

THE ATACAMA COSMOLOGY TELESCOPE: THE POLARIZATION-SENSITIVE ACTPol INSTRUMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thornton, R. J.; Ade, P. A. R.; Aiola, S.

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 thermalmore » 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.« less

The Atacama Cosmology Telescope: The Polarization-Sensitive ACTPol Instrument

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thornton, R. J.; Ade, P. A. R.; Aiola, S.

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 thermalmore » 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.« less

Camera Development for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Moncada, Roberto Jose

2017-01-01

With the Cherenkov Telescope Array (CTA), the very-high-energy gamma-ray universe, between 30 GeV and 300 TeV, will be probed at an unprecedented resolution, allowing deeper studies of known gamma-ray emitters and the possible discovery of new ones. This exciting project could also confirm the particle nature of dark matter by looking for the gamma rays produced by self-annihilating weakly interacting massive particles (WIMPs). The telescopes will use the imaging atmospheric Cherenkov technique (IACT) to record Cherenkov photons that are produced by the gamma-ray induced extensive air shower. One telescope design features dual-mirror Schwarzschild-Couder (SC) optics that allows the light to be finely focused on the high-resolution silicon photomultipliers of the camera modules starting from a 9.5-meter primary mirror. Each camera module will consist of a focal plane module and front-end electronics, and will have four TeV Array Readout with GSa/s Sampling and Event Trigger (TARGET) chips, giving them 64 parallel input channels. The TARGET chip has a self-trigger functionality for readout that can be used in higher logic across camera modules as well as across individual telescopes, which will each have 177 camera modules. There will be two sites, one in the northern and the other in the southern hemisphere, for full sky coverage, each spanning at least one square kilometer. A prototype SC telescope is currently under construction at the Fred Lawrence Whipple Observatory in Arizona. This work was supported by the National Science Foundation's REU program through NSF award AST-1560016.

VizieR Online Data Catalog: Five years of blazar observations with VERITAS (Archambault+, 2016)

NASA Astrophysics Data System (ADS)

Archambault, S.; Archer, A.; Benbow, W.; Bird, R.; Biteau, J.; Buchovecky, M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cerruti, M.; Chen, X.; Ciupik, L.; Connolly, M. P.; Cui, W.; Eisch, J. D.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Fortin, P.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Griffin, S.; Grube, J.; Gyuk, G.; Hutten, M.; Hakansson, N.; Hanna, D.; Holder, J.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Krennrich, F.; Kumar, S.; Lang, M. J.; Maier, G.; McArthur, S.; McCann, A.; Meagher, K.; Moriarty, P.; Mukherjee, R.; Nguyen, T.; Nieto, D.; O'Faolain de Bhroithe, A.; Ong, R. A.; Otte, A. N.; Park, N.; Perkins, J. S.; Pichel, A.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Rovero, A. C.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Vincent, S.; Wakely, S. P.; Weiner, O. M.; Weinstein, A.; Williams, D. A.; Zitzer, B.

2018-04-01

In this paper, we present the results of the analysis of most of the non-detected blazars observed by VERITAS from 2007 (the beginning of full-scale scientific operations) to 2012 August (before the upgrade of the VERITAS array, see Kieda 2013arXiv1308.4849D). The VERITAS (Very Energetic Radiation Imaging Telescope Array System) telescope array is composed of four IACTs of 12 m diameter each, located at the Fred Lawrence Whipple Observatory, on the slopes of Mount Hopkins, in southern Arizona (31°40'N, 110°57'W). Each telescope has a segmented mirror that focuses light onto a camera composed of 499 photomultipliers located at the focal plane. The instrument FOV is 3.5°. For further details on the VERITAS instrument, see Holder et al. (2006APh....25..391H) and Holder (2011ICRC...12..137H). The VERITAS observations here have an average length of 20 minutes (referred to as a run), before switching targets or wobble directions. (7 data files).

Demonstration of a Segment Alignment Maintenance System on a Seven-Segment Sub-Array of the Hobby-Eberly Telescope

NASA Technical Reports Server (NTRS)

Rakoczy, John; Whitaker, Ann F. (Technical Monitor)

2001-01-01

NASA's Marshall Space Flight Center, in collaboration with Blue Line Engineering of Colorado Springs, Colorado, is developing a Segment Alignment Maintenance System (SAMS) for McDonald Observatory's Hobby-Eberly Telescope (HET). The SAMS shall sense motions of the 91 primary mirror segments and send corrections to HET's primary mirror controller as the mirror segments misalign due to thermo-elastic deformations of the mirror support structure. The SAMS consists of inductive edge sensors supplemented by inclinometers for global radius of curvature sensing. All measurements are sent to the SAMS computer where mirror motion corrections are calculated. In October 2000, a prototype SAMS was installed on a seven-segment cluster of the HET. Subsequent testing has shown that the SAMS concept and architecture are a viable practical approach to maintaining HET's primary mirror figure, or the figure of any large segmented telescope. This paper gives a functional description of the SAMS sub-array components and presents test data to characterize the performance of the sub-array SAMS.

A Sentry on the Universe

NASA Astrophysics Data System (ADS)

Dixon, Robert

This chapter introduces the Argus radio telescope concept, a radically new approach to radio telescope design (not to be confused with The SETI League's Project Argus, a linked global array of fairly conventional radio telescopes). It represents a complete departure from designs that have been used ever since the invention of the first telescope by Galileo in 1609. It starts over from the beginning, and in doing so overcomes the legacy of Galileo. Argus can do things that are amazing and even hard to believe, when viewed in the context of previous telescopes. Here are some examples.

Baldes de fotones para espectrógrafos ópticos

NASA Astrophysics Data System (ADS)

Townsend, A.; Eikenberry, S.; Warner, C.; Donoso, V.; Díaz, R.; Levato, H.

2017-10-01

In order to implement low-cost large-aperture ground-based optical spectroscopy systems we are using inexpensive commercial-off-the-shelf telescopes and components to create semi-autonomous small telescope arrays and fiber-fed spectrographs. Small telescopes used conjointly (``photonic lightbuckets'') and connected by our new fiber-optic linkage have the effective light-gathering area of a larger telescope for about one-tenth of the cost. For the first prototype, we plan to feed the the LHIRES and BHROS spectrographs at ICATE with the equivalent collecting area of a one meter telescope.

The GISMO-2 Bolometer Camera

NASA Technical Reports Server (NTRS)

Staguhn, Johannes G.; Benford, Dominic J.; Fixsen, Dale J.; Hilton, Gene; Irwin, Kent D.; Jhabvala, Christine A.; Kovacs, Attila; Leclercq, Samuel; Maher, Stephen F.; Miller, Timothy M.;

The Atacama Cosmology Telescope: Instrument

NASA Astrophysics Data System (ADS)

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.

KSC-2012-1360

NASA Image and Video Library

2012-02-16

VANDENBERG AIR FORCE BASE, Calif. -- NuSTAR’s X-ray telescope is visible during the solar array deployment test at Vandenberg Air Force Base's processing facility in California. The Pegasus will launch NASA's Nuclear Spectroscopic Telescope Array NuSTAR into space. After the rocket and spacecraft are processed at Vandenberg, they will be flown on the Orbital Sciences’ L-1011 carrier aircraft to the Ronald Reagan Ballistic Missile Defense Test Site at the Pacific Ocean’s Kwajalein Atoll for launch. The high-energy x-ray telescope will conduct a census for black holes, map radioactive material in young supernovae remnants, and study the origins of cosmic rays and the extreme physics around collapsed stars. For more information, visit science.nasa.gov/missions/nustar/. Photo credit: NASA/Randy Beaudoin, VAFB

KSC-2012-1358

NASA Image and Video Library

2012-02-16

VANDENBERG AIR FORCE BASE, Calif. -- As a technician monitors the solar array deployment test at Vandenberg Air Force Base's processing facility in California, NuSTAR’s X-ray telescope is visible. The Pegasus will launch NASA's Nuclear Spectroscopic Telescope Array NuSTAR into space. After the rocket and spacecraft are processed at Vandenberg, they will be flown on the Orbital Sciences’ L-1011 carrier aircraft to the Ronald Reagan Ballistic Missile Defense Test Site at the Pacific Ocean’s Kwajalein Atoll for launch. The high-energy x-ray telescope will conduct a census for black holes, map radioactive material in young supernovae remnants, and study the origins of cosmic rays and the extreme physics around collapsed stars. For more information, visit science.nasa.gov/missions/nustar/. Photo credit: NASA/Randy Beaudoin, VAFB

KSC-2012-1359

NASA Image and Video Library

2012-02-16

VANDENBERG AIR FORCE BASE, Calif. -- As a technician monitors the solar array deployment test at Vandenberg Air Force Base's processing facility in California, NuSTAR’s X-ray telescope is visible. The Pegasus will launch NASA's Nuclear Spectroscopic Telescope Array NuSTAR into space. After the rocket and spacecraft are processed at Vandenberg, they will be flown on the Orbital Sciences’ L-1011 carrier aircraft to the Ronald Reagan Ballistic Missile Defense Test Site at the Pacific Ocean’s Kwajalein Atoll for launch. The high-energy x-ray telescope will conduct a census for black holes, map radioactive material in young supernovae remnants, and study the origins of cosmic rays and the extreme physics around collapsed stars. For more information, visit science.nasa.gov/missions/nustar/. Photo credit: NASA/Randy Beaudoin, VAFB

HST Solar Arrays photographed by Electronic Still Camera

NASA Image and Video Library

1993-12-07

S61-E-020 (7 Dec 1993) --- This close-up view of one of two Solar Arrays (SA) on the Hubble Space Telescope (HST) was photographed with an Electronic Still Camera (ESC), and down linked to ground controllers soon afterward. Endeavour's crew captured the HST on December 4, 1993, in order to service the telescope over a period of five days. Four of the crew members will work in alternating pairs outside Endeavour's shirt sleeve environment to service the giant telescope. Electronic still photography is a relatively new technology which provides the means for a handheld camera to electronically capture and digitize an image with resolution approaching film quality. The electronic still camera has flown as an experiment on several other shuttle missions.

First Surface-resolved Results with the Infrared Optical Telescope Array Imaging Interferometer: Detection of Asymmetries in Asymptotic Giant Branch Stars

NASA Astrophysics Data System (ADS)

Ragland, S.; Traub, W. A.; Berger, J.-P.; Danchi, W. C.; Monnier, J. D.; Willson, L. A.; Carleton, N. P.; Lacasse, M. G.; Millan-Gabet, R.; Pedretti, E.; Schloerb, F. P.; Cotton, W. D.; Townes, C. H.; Brewer, M.; Haguenauer, P.; Kern, P.; Labeye, P.; Malbet, F.; Malin, D.; Pearlman, M.; Perraut, K.; Souccar, K.; Wallace, G.

2006-11-01

We have measured nonzero closure phases for about 29% of our sample of 56 nearby asymptotic giant branch (AGB) stars, using the three-telescope Infrared Optical Telescope Array (IOTA) interferometer at near-infrared wavelengths (H band) and with angular resolutions in the range 5-10 mas. These nonzero closure phases can only be generated by asymmetric brightness distributions of the target stars or their surroundings. We discuss how these results were obtained and how they might be interpreted in terms of structures on or near the target stars. We also report measured angular sizes and hypothesize that most Mira stars would show detectable asymmetry if observed with adequate angular resolution.

Superconducting Detectors for Study of Infant Universe

NASA Image and Video Library

2014-03-17

The BICEP2 telescope at the South Pole used a specialized array of superconducting detectors to capture polarized light from billions of years ago. The detector array is shown here, under a microscope.

Diffusion-Weighted Imaging of Traumatic Optic Neuropathy: Diagnosis and Predicting the Prognosis

DTIC Science & Technology

2014-01-01

AFRL-SA-WP-SR-2014-0004 Diffusion-Weighted Imaging of Traumatic Optic Neuropathy : Diagnosis and Predicting the Prognosis...Diffusion-Weighted Imaging of Traumatic Optic Neuropathy : Diagnosis and Predicting the Prognosis 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...Skills Institute C-STARS Baltimore 2510 Fifth St. Wright-Patterson AFB, OH 45433-7913 8 . PERFORMING ORGANIZATION REPORT NUMBER AFRL-SA

Simulated gamma-ray pulse profile of the Crab pulsar with the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Burtovoi, A.; Zampieri, L.

2016-07-01

We present simulations of the very high energy (VHE) gamma-ray light curve of the Crab pulsar as observed by the Cherenkov Telescope Array (CTA). The CTA pulse profile of the Crab pulsar is simulated with the specific goal of determining the accuracy of the position of the interpulse. We fit the pulse shape obtained by the Major Atmospheric Gamma-Ray Imaging Cherenkov (MAGIC) telescope with a three-Gaussian template and rescale it to account for the different CTA instrumental and observational configurations. Simulations are performed for different configurations of CTA and for the ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) mini-array. The northern CTA configuration will provide an improvement of a factor of ˜3 in accuracy with an observing time comparable to that of MAGIC (73 h). Unless the VHE spectrum above 1 TeV behaves differently from what we presently know, unreasonably long observing times are required for a significant detection of the pulsations of the Crab pulsar with the high-energy-range sub-arrays. We also found that an independent VHE timing analysis is feasible with Large Size Telescopes. CTA will provide a significant improvement in determining the VHE pulse shape parameters necessary to constrain theoretical models of the gamma-ray emission of the Crab pulsar. One of such parameters is the shift in phase between peaks in the pulse profile at VHE and in other energy bands that, if detected, may point to different locations of the emission regions.

Self-Referencing Hartmann Test for Large-Aperture Telescopes

NASA Technical Reports Server (NTRS)

Korechoff, Robert P.; Oseas, Jeffrey M.

2010-01-01

A method is proposed for end-to-end, full aperture testing of large-aperture telescopes using an innovative variation of a Hartmann mask. This technique is practical for telescopes with primary mirrors tens of meters in diameter and of any design. Furthermore, it is applicable to the entire optical band (near IR, visible, ultraviolet), relatively insensitive to environmental perturbations, and is suitable for ambient laboratory as well as thermal-vacuum environments. The only restriction is that the telescope optical axis must be parallel to the local gravity vector during testing. The standard Hartmann test utilizes an array of pencil beams that are cut out of a well-corrected wavefront using a mask. The pencil beam array is expanded to fill the full aperture of the telescope. The detector plane of the telescope is translated back and forth along the optical axis in the vicinity of the nominal focal plane, and the centroid of each pencil beam image is recorded. Standard analytical techniques are then used to reconstruct the telescope wavefront from the centroid data. The expansion of the array of pencil beams is usually accomplished by double passing the beams through the telescope under test. However, this requires a well-corrected, autocollimation flat, the diameter or which is approximately equal to that of the telescope aperture. Thus, the standard Hartmann method does not scale well because of the difficulty and expense of building and mounting a well-corrected, large aperture flat. The innovation in the testing method proposed here is to replace the large aperture, well-corrected, monolithic autocollimation flat with an array of small-aperture mirrors. In addition to eliminating the need for a large optic, the surface figure requirement for the small mirrors is relaxed compared to that required of the large autocollimation flat. The key point that allows this method to work is that the small mirrors need to operate as a monolithic flat only with regard to tip/tilt and not piston because in collimated space piston has no effect on the image centroids. The problem of aligning the small mirrors in tip/tilt requires a two-part solution. First, each mirror is suspended from a two-axis gimbal. The orientation of the gimbal is maintained by gravity. Second, the mirror is aligned such that the mirror normal is parallel to gravity vector. This is accomplished interferometrically in a test fixture. Of course, the test fixture itself needs to be calibrated with respect to gravity.

The hyperion particle-γ detector array

DOE PAGES

Hughes, R. O.; Burke, J. T.; Casperson, R. J.; ...

2017-03-08

Hyperion is a new high-efficiency charged-particle γ-ray detector array which consists of a segmented silicon telescope for charged-particle detection and up to fourteen high-purity germanium clover detectors for the detection of coincident γ rays. The array will be used in nuclear physics measurements and Stockpile Stewardship studies and replaces the STARLiTeR array. In conclusion, this article discusses the features of the array and presents data collected with the array in the commissioning experiment.

Exploring the performance of large-N radio astronomical arrays

NASA Astrophysics Data System (ADS)

Lonsdale, Colin J.; Doeleman, Sheperd S.; Cappallo, Roger J.; Hewitt, Jacqueline N.; Whitney, Alan R.

2000-07-01

New radio telescope arrays are currently being contemplated which may be built using hundreds, or even thousands, of relatively small antennas. These include the One Hectare Telescope of the SETI Institute and UC Berkeley, the LOFAR telescope planned for the New Mexico desert surrounding the VLA, and possibly the ambitious international Square Kilometer Array (SKA) project. Recent and continuing advances in signal transmission and processing technology make it realistic to consider full cross-correlation of signals from such a large number of antennas, permitting the synthesis of an aperture with much greater fidelity than in the past. In principle, many advantages in instrumental performance are gained by this 'large-N' approach to the design, most of which require the development of new algorithms. Because new instruments of this type are expected to outstrip the performance of current instruments by wide margins, much of their scientific productivity is likely to come from the study of objects which are currently unknown. For this reason, instrumental flexibility is of special importance in design studies. A research effort has begun at Haystack Observatory to explore large-N performance benefits, and to determine what array design properties and data reduction algorithms are required to achieve them. The approach to these problems, involving a sophisticated data simulator, algorithm development, and exploration of array configuration parameter space, will be described, and progress to date will be summarized.

Polarization Angle Calibration and B-Mode Characterization with the BICEP and Keck Array CMB Telescopes

NASA Astrophysics Data System (ADS)

Bullock, Eric

Since its discovery in 1964, the Cosmic Microwave Background (CMB) has led to widespread acceptance of the Big Bang cosmological paradigm as an explanation for the evolution of the Universe. However, this paradigm does not explain the origin of the initial conditions, leading to such issues as the "horizon problem" and "flatness problem." In the early 1980's, the inflationary paradigm was introduced as a possible source for the initial conditions. This theory postulates that the Universe underwent a period of exponential expansion within a tiny fraction of a second after the beginning. Such an expansion is predicted to inject a stochastic background of gravitational waves that could imprint a detectable B-mode (curl-like) signal in the polarization of the CMB. It is this signal that the family of telescopes used by the B ICEP1, BICEP2, and Keck Array collaborations were designed to detect. These telescopes are small aperture, on-axis, refracting telescopes. We have used the data from these telescopes, particularly BICEP2 and the Keck Array, to place the tightest constraints, as of March 2016, on the tensor-to-scalar ratio of the CMB of r 0.05 < 0.07. In this dissertation, we provide an overview of the Keck Array telescopes and analysis of the data. We also investigate, as the main focus of this dissertation, a device we call the Dielectric Sheet Calibrator (DSC) that is used to measure the polarization angles of our detectors as projected on the sky. With these measurements, we gain the potential to separate the polarization rotation effects of parity-violating physics, such as cosmic birefringence, from a systematic uncertainty on our detectors' polarization angles. Current calibration techniques for polarization sensitive CMB detectors claim an accuracy of +/-0.5°, which sets a limit for determining the usefulness of the DSC. Through a series of consistency tests on a single Keck Array receiver, we demonstrate a statistical uncertainty on the DSC measurements of +/-0.03° and estimate a systematic uncertainty of +/-0.2°. which meets the minimum goal. We also conclude that there is no conflict between the DSC-derived polarization angles of this single receiver and the rotation derived from that receiver's CMB data under the hypothesis of no cosmic birefringence.

Calibrating Images from the MINERVA Cameras

NASA Astrophysics Data System (ADS)

Mercedes Colón, Ana

2016-01-01

The MINiature Exoplanet Radial Velocity Array (MINERVA) consists of an array of robotic telescopes located on Mount Hopkins, Arizona with the purpose of performing transit photometry and spectroscopy to find Earth-like planets around Sun-like stars. In order to make photometric observations, it is necessary to perform calibrations on the CCD cameras of the telescopes to take into account possible instrument error on the data. In this project, we developed a pipeline that takes optical images, calibrates them using sky flats, darks, and biases to generate a transit light curve.

EVA 2 - MS Newman over Australia

NASA Image and Video Library

2002-03-05

STS109-E-5611 (5 March 2002) --- Astronauts James H. Newman, attached to the Remote Manipulator System (RMS) arm of the Space Shuttle Columbia, and Michael J. Massimino (out of frame) work on the Hubble Space Telescope as the shuttle flies over Western Australia. This day's space walk went on to see astronauts Newman and Massimino replace the port solar array on the Hubble. On the previous day astronauts John M. Grunsfeld and Richard M. Linnehan replaced the starboard solar array on the giant telescope. The image was recorded with a digital still camera.

JWST Near-Infrared Detectors: Latest Test Results

NASA Technical Reports Server (NTRS)

Smith, Erin C.; Rauscher, Bernard J.; Alexander, David; Brambora, Clifford K.; Chiao, Meng; Clemons, Brian L.; Derro, Rebecca; Engler, Chuck; Fox, Ori; Garrison, Matthew B.;

STS-31 Hubble Space Telescope (HST) solar array (SA) deploy aboard OV-103

NASA Image and Video Library

1990-04-25

During STS-31, the Hubble Space Telescope (HST) is held in appendage deploy position by Discovery's, Orbiter Vehicle (OV) 103's, remote manipulator system (RMS) above the payload bay (PLB) and crew compartment cabin. While in this position the solar array (SA) wing bistem cassette (HST center) is deployed from its stowed location along side the Support System Module (SSM) forward shell. A high gain antenna (HGA) remains stowed along the SSM. The Earth's surface and the Earth limb creates a dramatic backdrop.

Commissioning Results on the JWST Testbed Telescope

NASA Technical Reports Server (NTRS)

Dean, Bruce H.; Acton, D. Scott

2006-01-01

The one-meter 18 segment JWST Testbed Telescope (TBT) has been developed at Ball Aerospace to facilitate commissioning operations for the JWST Observatory. Eight different commissioning activities were tested on the TBT: telescope focus sweep, segment ID and Search, image array, global alignment, image stacking, coarse phasing, fine phasing, and multi-field phasing. This paper describes recent commissioning results from experiments performed on the TBT.

Primary gamma ray selection in a hybrid timing/imaging Cherenkov array

NASA Astrophysics Data System (ADS)

Postnikov, E. B.; Grinyuk, A. A.; Kuzmichev, L. A.; Sveshnikova, L. G.

2017-06-01

This work is a methodical study on hybrid reconstruction techniques for hybrid imaging/timing Cherenkov observations. This type of hybrid array is to be realized at the gamma-observatory TAIGA intended for very high energy gamma-ray astronomy (> 30 TeV). It aims at combining the cost-effective timing-array technique with imaging telescopes. Hybrid operation of both of these techniques can lead to a relatively cheap way of development of a large area array. The joint approach of gamma event selection was investigated on both types of simulated data: the image parameters from the telescopes, and the shower parameters reconstructed from the timing array. The optimal set of imaging parameters and shower parameters to be combined is revealed. The cosmic ray background suppression factor depending on distance and energy is calculated. The optimal selection technique leads to cosmic ray background suppression of about 2 orders of magnitude on distances up to 450 m for energies greater than 50 TeV.

Wide-field-of-view millimeter-wave telescope design with ultra-low cross-polarization

NASA Astrophysics Data System (ADS)

Bernacki, Bruce E.; Kelly, James F.; Sheen, David; Hatchell, Brian; Valdez, Patrick; Tedeschi, Jonathan; Hall, Thomas; McMakin, Douglas

2012-06-01

As millimeter-wave arrays become available, off-axis imaging performance of the fore optics increases in importance due to the relatively large physical extent of the arrays. Typically, simple optical telescope designs are adapted to millimeter-wave imaging but single-mirror spherical or classic conic designs cannot deliver adequate image quality except near the optical axis. Since millimeter-wave designs are quasi-optical, optical ray tracing and commercial design software can be used to optimize designs to improve off-axis imaging as well as minimize cross-polarization. Methods that obey the Dragone-Mizuguchi condition for the design of reflective millimeter-wave telescopes with low cross-polarization also provide additional degrees of freedom that offer larger fields of view than possible with single-reflector designs. Dragone's graphical design method does not lend itself readily to computer-based optical design approaches, but subsequent authors expanded on Dragone's geometric design approach with analytic expressions that describe the location, shape, off-axis height and tilt of the telescope elements that satisfy Dragone's design rules and can be used as a first-order design for subsequent computer-based design and optimization. We investigate two design variants that obey the Dragone-Mizuguchi conditions that exhibit ultra-low cross-polarization and a large diffraction-limited field of view well suited to millimeter-wave imaging arrays.

The AuScope geodetic VLBI array

NASA Astrophysics Data System (ADS)

Lovell, J. E. J.; McCallum, J. N.; Reid, P. B.; McCulloch, P. M.; Baynes, B. E.; Dickey, J. M.; Shabala, S. S.; Watson, C. S.; Titov, O.; Ruddick, R.; Twilley, R.; Reynolds, C.; Tingay, S. J.; Shield, P.; Adada, R.; Ellingsen, S. P.; Morgan, J. S.; Bignall, H. E.

2013-06-01

The AuScope geodetic Very Long Baseline Interferometry array consists of three new 12-m radio telescopes and a correlation facility in Australia. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) are co-located with other space geodetic techniques including Global Navigation Satellite Systems (GNSS) and gravity infrastructure, and in the case of Yarragadee, satellite laser ranging (SLR) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) facilities. The correlation facility is based in Perth (Western Australia). This new facility will make significant contributions to improving the densification of the International Celestial Reference Frame in the Southern Hemisphere, and subsequently enhance the International Terrestrial Reference Frame through the ability to detect and mitigate systematic error. This, combined with the simultaneous densification of the GNSS network across Australia, will enable the improved measurement of intraplate deformation across the Australian tectonic plate. In this paper, we present a description of this new infrastructure and present some initial results, including telescope performance measurements and positions of the telescopes in the International Terrestrial Reference Frame. We show that this array is already capable of achieving centimetre precision over typical long-baselines and that network and reference source systematic effects must be further improved to reach the ambitious goals of VLBI2010.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, R. O.; Burke, J. T.; Casperson, R. J.

Hyperion is a new high-efficiency charged-particle γ-ray detector array which consists of a segmented silicon telescope for charged-particle detection and up to fourteen high-purity germanium clover detectors for the detection of coincident γ rays. The array will be used in nuclear physics measurements and Stockpile Stewardship studies and replaces the STARLiTeR array. In conclusion, this article discusses the features of the array and presents data collected with the array in the commissioning experiment.

Variable-delay Polarization Modulators for the CLASS Telescope

NASA Astrophysics Data System (ADS)

Harrington, Kathleen; Ali, A.; Amiri, M.; Appel, J. W.; Araujo, D.; Bennett, C. L.; Boone, F.; Chan, M.; Cho, H.; Chuss, D. T.; Colazo, F.; Crowe, E.; Denis, K.; Dünner, R.; Eimer, J.; Essinger-Hileman, T.; Gothe, D.; Halpern, M.; Hilton, G.; Hinshaw, G. F.; Huang, C.; Irwin, K.; Jones, G.; Karakla, J.; Kogut, A. J.; Larson, D.; Limon, M.; Lowry, L.; Marriage, T.; Mehrle, N.; Miller, A. D.; Miller, N.; Mirel, P.; Moseley, S. H.; Novak, G.; Reintsema, C.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wagner, E.; Watts, D.; Wollack, E.; Xu, Z.; Zeng, L.

2014-01-01

The challenges of measuring faint polarized signals at microwave wavelengths have motivated the development of rapid polarization modulators. One scalable technique, called a Variable-delay Polarization Modulator (VPM), consists of a stationary wire array in front of a movable mirror. The mirror motion creates a changing phase difference between the polarization modes parallel and orthogonal to the wire array. The Cosmology Large Angular Scale Surveyor (CLASS) will use a VPM as the first optical element in a telescope array that will search for the signature of inflation through the “B-mode” pattern in the polarization of the cosmic microwave background. In the CLASS VPMs, parallel transport of the mirror is maintained by a voice-coil actuated flexure system which will translate the mirror in a repeatable manner while holding tight parallelism constraints with respect to the wire array. The wire array will use 51 μm diameter copper-plated tungsten wire with 160 μm pitch over a 60 cm clear aperture. We present the status of the construction and testing of the mirror transport mechanism and wire arrays for the CLASS VPMs.

Muon Detector R&D in Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Nonaka, T.; Takamura, M.; Honda, K.; Matthews, J. N.; Ogio, S.; Sakurai, N.; Sagawa, H.; Stokes, B. T.; Tsujimoto, M.; Yashiro, K.

The Telescope Array (TA) experiment, located in the western desert of Utah, U.S.A., at 39.38° north and 112.9° west, is collecting data of ultra high energy cosmic rays in the energy range 1018-1020 eV. The experiment has a Surface Detector (SD) array surrounded by three Fluorescence Detector (FD) stations to enable simultaneous detection of shower particles and fluorescence photons generated by the extensive air shower. Measurement of shower particles at the ground level, with different absorber thickness, enables a more detailed studies of the experiment's energy scale and of hadron interaction models. In this report, we present a design and the first observation result of a surface muon detector using lead plates and concrete as absorbers.

Argus: A W-band 16-pixel focal plane array for the Green Bank Telescope

NASA Astrophysics Data System (ADS)

Devaraj, Kiruthika; Church, Sarah; Cleary, Kieran; Frayer, David; Gawande, Rohit; Goldsmith, Paul; Gundersen, Joshua; Harris, Andrew; Kangaslahti, Pekka; Readhead, Tony; Reeves, Rodrigo; Samoska, Lorene; Sieth, Matt; Voll, Patricia

2015-05-01

We are building Argus, a 16-pixel square-packed focal plane array that will cover the 75-115.3 GHz frequency range on the Robert C. Byrd Green Bank Telescope (GBT). The primary research area for Argus is the study of star formation within our Galaxy and nearby galaxies. Argus will map key molecules that trace star formation, including carbon monoxide (CO) and hydrogen cyanide (HCN). An additional key science area is astrochemistry, which will be addressed by observing complex molecules in the interstellar medium, and the study of formation of solar systems, which will be addressed by identifying dense pre-stellar cores and by observing comets in our solar system. Argus has a highly scalable architecture and will be a technology path finder for larger arrays. The array is modular in construction, which will allow easy replacement of malfunctioning and poorly performing components.

Development and Calibration of the ART-XC Mirror Modules for the Spectrum Rontgen Gamma Mission

NASA Technical Reports Server (NTRS)

Ramsey, B.; Gubarev, M.; Elsner, R.; Kolodziejczak, J.; Odell, S.; Swartz, D.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.

2013-01-01

The Spectrum-Röntgen-Gamma (SRG) mission is a Russian-lead X-ray astrophysical observatory that carries two co-aligned X-ray telescope systems. The primary instrument is the German-led extended ROentgen Survey with an Imaging Telescope Array (eROSITA), a 7-module X-ray telescope system that covers the energy range from 0.2-12 keV. The complementary instrument is the Astronomical Roentgen Telescope -- X-ray Concentrator (ART-XC or ART), a 7-module Xray telescope system that provides higher energy coverage, up to 30 keV.

Trends in measurement of solar vector magnetic fields using the Zeeman effect

NASA Technical Reports Server (NTRS)

Harvey, J. W.

1985-01-01

Trends in spectropolarimetry as applied to the problem of Zeeman effect measurement are discussed. The use of detector arrays to improve observing efficiency is obtained. Which required new polarization modulation schemes that match the time required to read detector arrays. Another significant trend is narrowband filters, to improve angular and temporal coverage, and to Fourier transform spectrometers, to improve spectral coverage and precision. Low-polarization designs and improved methods for compensating instrumental polarization were developed. A requirement for high angular resolution suggests using adaptive optical devices to subdue the effects of bad seeing. The ultimate strategy to beat the seeing is to loft the telescope above the atmosphere such as is planned with a 30-cm telescope in 1985 and a 1250-cm telescope in 1990.

Development of the MAMA Detectors for the Hubble Space Telescope Imaging Spectrograph

NASA Technical Reports Server (NTRS)

Timothy, J. Gethyn

1997-01-01

The development of the Multi-Anode Microchannel Array (MAMA) detector systems started in the early 1970's in order to produce multi-element detector arrays for use in spectrographs for solar studies from the Skylab-B mission. Development of the MAMA detectors for spectrographs on the Hubble Space Telescope (HST) began in the late 1970's, and reached its culmination with the successful installation of the Space Telescope Imaging Spectrograph (STIS) on the second HST servicing mission (STS-82 launched 11 February 1997). Under NASA Contract NAS5-29389 from December 1986 through June 1994 we supported the development of the MAMA detectors for STIS, including complementary sounding rocket and ground-based research programs. This final report describes the results of the MAMA detector development program for STIS.

Monitoring of Arctic Conditions from a Virtual Constellation of Synthetic Aperture Radar Satellites

DTIC Science & Technology

2014-09-30

Constellation of Synthetic Aperture Radar Satellites RSMAS – Department of Ocean Sciences Center for Southeastern Tropical Advanced Remote Sensing...fax: (305) 421-4696 email: pminnett@rsmas.miami.edu Award Number: N00014-12-1-0448 LONG-TERM GOALS Utilize a constellation of satellite...OBJECTIVES a) Provide daily Arctic situational awareness from the CSTARS SAR satellite constellation . b) Develop a Neural Network algorithm for ice-type

Studies of Avalanche Photodiodes (APDS) as Readout Devices for Scintillating Fibers for High Energy Gamma-Ray Astronomy Telescopes

NASA Technical Reports Server (NTRS)

Vasile, Stefan; Shera, Suzanne; Shamo, Denis

1998-01-01

New gamma ray and charged particle telescope designs based on scintillating fiber arrays could provide low cost, high resolution, lightweight, very large area and multi radiation length instrumentation for planned NASA space exploration. The scintillating fibers low visible light output requires readout sensors with single photon detection sensitivity and low noise. The sensitivity of silicon Avalanche Photodiodes (APDS) matches well the spectral output of the scintillating fibers. Moreover, APDs have demonstrated single photon capability. The global aim of our work is to make available to NASA a novel optical detector concept to be used as scintillating fiber readouts and meeting the requirements of the new generations of space-borne gamma ray telescopes. We proposed to evaluate the feasibility of using RMD's small area APDs ((mu)APD) as scintillating fiber readouts and to study possible alternative (mu)APD array configurations for space borne readout scintillating fiber systems, requiring several hundred thousand to one million channels. The evaluation has been conducted in accordance with the task description and technical specifications detailed in the NASA solicitation "Studies of Avalanche Photodiodes (APD as readout devices for scintillating fibers for High Energy Gamma-Ray Astronomy Telescopes" (#8-W-7-ES-13672NAIS) posted on October 23, 1997. The feasibility study we propose builds on recent developments of silicon APD arrays and light concentrators advances at RMD, Inc. and on more than 5 years of expertise in scintillating fiber detectors. In a previous program we carried out the initial research to develop a high resolution, small pixel, solid-state, silicon APD array which exhibited very high sensitivity in the UV-VIS spectrum. This (mu)APD array is operated in Geiger mode and results in high gain (greater than 10(exp 8)), extremely low noise, single photon detection capability, low quiescent power (less than 10 (mu)W/pixel for 30 micrometers sensitive area diameter) and output in the 1-5 volt range. If successful, this feasibility study will make possible the development of a scintillating fiber detector with unsurpassed sensitivity, extremely low power usage, a crucial factor of merit for space based sensors and telescopes.

The ASTRI SST-2M prototype for the Cherenkov Telescope Array: prototype technologies goals and strategies for the future SST

NASA Astrophysics Data System (ADS)

Marchiori, Gianpietro; Busatta, Andrea; Giacomel, Stefano; Folla, Ivan; Valsecchi, Marco; Canestrari, Rodolfo; Bonnoli, Giacomo; Cascone, Enrico; Conconi, Paolo; Fiorini, Mauro; Giro, Enrico; La Palombara, Nicola; Pareschi, Giovanni; Perri, Luca; Rodeghiero, Gabriele; Sironi, Giorgia; Stringhetti, Luca; Toso, Giorgio; Tosti, Gino; Pellicciari, Carlo

2014-07-01

The Cherenkov Telescope Array (CTA) observatory will represent the next generation of Imaging Atmospheric Cherenkov Telescope. Using a combination of large-, medium-, and small-scale telescopes (LST, MST, SST, respectively), it will explore the Very High Energy domain from a few tens of GeVup to about few hundreds of TeV with unprecedented sensitivity, angular resolution and imaging quality. In this framework, the Italian ASTRI program, led by the Italian National Institute of Astrophysics (INAF) developed a 4-meter class telescope, which will adopt an aplanatic, wide-field, double-reflection optical layout in a Schwarzschild- Couder configuration. Within this program INAF assigned to the consortium between Galbiati Group and EIE Group the construction, assembly and tests activities of the prototype named ASTRI SST-2M. On the basis of the lesson learnt from the prototype, other telescopes will be produced, starting from a re-design phase, in order to optimize performances and the overall costs and production schedule for the CTA-SST telescope. This paper will firstly give an overview of the concept for the SST prototype mount structure. In this contest, the technologies adopted for the design, manufacturing and tests of the entire system will be presented. Moreover, a specific focus on the challenges of the prototype and the strategies associated with it will be provided, in order to outline the near future performance goals for this type of Cherenkov telescopes employed for Gamma ray science.

Interferometric capability for the Magellan Project

NASA Astrophysics Data System (ADS)

Carleton, Nathaniel P.; Traub, Wesley A.; Angel, J. Roger P.

1998-07-01

The Magellan Project is building two 6.5-m telescopes, 60 m apart, at the Las Campanas Observatory in Chile. There are on-going plans to combine the beams of the two main telescopes, and of smaller auxiliary telescopes, for interferometric measurements. In this paper we consider the array of auxiliary telescopes as a stand-alone instrument, recognizing that it will operate as such for some large fraction of the time. Our interest is sharpened by the availability of six 1.8-m optical systems, retired from the Smithsonian-Arizona Multiple-Mirror Telescope in preparation for the installation of a single-mirror 6.5-m system. We have completed a design for a 1.8-m telescope, in which the MMT components are supported on a proven tripod mount. The optics-support uses steel for stiffness, and low-thermal- expansion rods for passive stability. This array will be a powerful tool for the investigation of stellar limb darkening, surface features, and changes of diameter in pulsations, as well as dust disks, shells, and binary companions. The 1.8-m telescopes on good sites such as Magellan's should be able to operate at full aperture for interferometry at 2.2 micrometers . They should therefore be able to reach to magnitude K equals 10 or so, and thus to cover substantial samples of both main-sequence and pre-main- sequence stars, and of fully evolved stars as well.

Caracterización de un sistema de telescopios Cherenkov para la detección de rayos gamma de energías del TeV desde el CASLEO

NASA Astrophysics Data System (ADS)

Melo, D.; Yelós, L. D.; Garcia, B.; Rovero, A. C.

2017-10-01

Gamma-ray astronomy opened the universe of the more energetic electromagnetic radiation using ground and orbiting instruments, which provide information for the understanding of sources of different types. Ground-based telescope arrays use Cherenkov light produced by the charged particles from extensive air showers generated in the Earth's atmosphere to identify gamma rays. This imposes a minimum energy threshold on the gamma rays to be detected. Towards the high-energy end of the spectrum, however, the amount of Cherenkov radiation produced by a gamma-ray photon guarantees its detectability, the limiting factor being the low flux of the sources. For this reason, the detection strategy consists in using arrays of small telescopes. In this work, we investigate the feasibility of detecting gamma-ray cascades using Cherenkov telescopes, in the range of 100 GeV to 2 TeV, at the CASLEO site, characterizing the response of a system of three Cherenkov telescopes.

Upgrades to MINERVA control software

NASA Astrophysics Data System (ADS)

Wilson, Maurice; Eastman, Jason D.

2017-01-01

The MINiature Exoplanet Radial Velocity Array (MINERVA) is an array of four robotic telescopes located on Mt. Hopkins in Arizona that will find and characterize rocky planets around our nearest stars. We discuss the latest upgrades to the MINERVA robotic control software. Previously, our robotic control software was only capable of taking radial velocities or photometry for the entire night, but not both. We have recently increased the speed and ease of transitioning between photometry and radial velocity (RV) observations. We can now arbitrarily assign a subset of the telescopes to either photometric or spectroscopic observations. This capability enables us to monitor stellar activity while measuring the star’s RV, gather photometry on one star while continuing our RV survey of other targets and provide education and public outreach opportunities where others can observe with one or more telescopes while we continue using the remaining telescopes for research. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. 1144152.

Optical calibration of the Auger fluorescence telescopes

NASA Astrophysics Data System (ADS)

Matthews, John A. J.

2003-02-01

The Pierre Auger Observatory is optimized to study the cosmic ray spectrum in the region of the Greisen-Zatsepin-Kuz'min (GZK) cutoff, i.e.cosmic rays with energies of ~1020eV. Cosmic rays are detected as extensive air showers. To measure these showers each Auger site combines a 3000sq-km ground array with air fluorescence telescopes into a hybrid detector. Our design choice is motivated by the heightened importance of the energy scale, and related systematic uncertainties in shower energies, for experiments investigating the GZK cutoff. This paper focuses on the optical calibration of the Auger fluorescence telescopes. The optical calibration is done three independent ways: an absolute end-to-end calibration using a uniform, calibrated intensity, light-source at the telescope entrance aperture, a component by component calibration using both laboratory and in-situ measurements, and Rayleigh scattered light from external laser beams. The calibration concepts and related instrumentation are summarized. Results from the 5-month engineering array test are presented.

MINERVA: Small Planets from Small Telescopes

NASA Astrophysics Data System (ADS)

Wittenmyer, Robert A.; Johnson, John Asher; Wright, Jason; McCrady, Nate; Swift, Jonathan; Bottom, Michael; Plavchan, Peter; Riddle, Reed; Muirhead, Philip S.; Herzig, Erich; Myles, Justin; Blake, Cullen H.; Eastman, Jason; Beatty, Thomas G.; Lin, Brian; Zhao, Ming; Gardner, Paul; Falco, Emilio; Criswell, Stephen; Nava, Chantanelle; Robinson, Connor; Hedrick, Richard; Ivarsen, Kevin; Hjelstrom, Annie; de Vera, Jon; Szentgyorgyi, Andrew

2015-09-01

The Kepler mission has shown that small planets are extremely common. It is likely that nearly every star in the sky hosts at least one rocky planet. We just need to look hard enough-but this requires vast amounts of telescope time. MINERVA (MINiature Exoplanet Radial Velocity Array) is a dedicated exoplanet observatory with the primary goal of discovering rocky, Earth-like planets orbiting in the habitable zone of bright, nearby stars. The MINERVA team is a collaboration among UNSW Australia, Harvard-Smithsonian Center for Astrophysics, Penn State University, University of Montana, and the California Institute of Technology. The four-telescope MINERVA array will be sited at the F.L. Whipple Observatory on Mt Hopkins in Arizona, USA. Full science operations will begin in mid-2015 with all four telescopes and a stabilised spectrograph capable of high-precision Doppler velocity measurements. We will observe ~100 of the nearest, brightest, Sun-like stars every night for at least five years. Detailed simulations of the target list and survey strategy lead us to expect new low-mass planets.

The First Year of Robotic Science with MINERVA

NASA Astrophysics Data System (ADS)

McCrady, Nate; Johnson, John A.; Wright, Jason; Wittenmyer, Robert; Eastman, Jason; Beatty, Thomas G.; Bottom, Michael; Johnson, Samson

2016-01-01

Detection of low-mass exoplanets orbiting Sun-like stars requires high cadence, long time-baseline observations that are impossible to obtain on shared large telescopes. MINERVA is a dedicated observatory for exoplanet detection that consists of four robotic 0.7-meter PlaneWave telescopes located at Whipple Observatory on Mt Hopkins, Arizona. First light science began in May 2015 with photometric monitoring of transit and microlensing events. The four telescopes can observe different targets, or provide simultaneous multi-color light curves of a single event. We will add a purpose-built, temperature-stabilized, high precision iodine cell spectrometer from Callaghan Innovation in 2016 to facilitate velocimetric search for low-mass exoplanets around nearby stars. The flexibility of the MINERVA array provides a natural avenue for educational and public outreach activities. One telescope in the array can break formation to observe targets from a queue or respond to remote operations from astronomy courses at a partner institution. MINERVA is a collaboration among Harvard U., Penn State U., U. Montana, and U. New South Wales.

A Major Upgrade of the H.E.S.S. Cherenkov Cameras

NASA Astrophysics Data System (ADS)

Lypova, Iryna; Giavitto, Gianluca; Ashton, Terry; Balzer, Arnim; Berge, David; Brun, Francois; Chaminade, Thomas; Delagnes, Eric; Fontaine, Gerard; Füßling, Matthias; Giebels, Berrie; Glicenstein, Jean-Francois; Gräber, Tobias; Hinton, Jim; Jahnke, Albert; Klepser, Stefan; Kossatz, Marko; Kretzschmann, Axel; Lefranc, Valentin; Leich, Holger; Lüdecke, Hartmut; Manigot, Pascal; Marandon, Vincent; Moulin, Emmanuel; de Naurois, Mathieu; Nayman, Patrick; Ohm, Stefan; Penno, Marek; Ross, Duncan; Salek, David; Schade, Markus; Schwab, Thomas; Simoni, Rachel; Stegmann, Christian; Steppa, Constantin; Thornhill, Julian; Toussnel, Francois

2017-03-01

The High Energy Stereoscopic System (H.E.S.S.) is an array of imaging atmospheric Cherenkov telescopes (IACTs) located in Namibia. It was built to detect Very High Energy (VHE, >100 GeV) cosmic gamma rays, and consists of four 12 m diameter Cherenkov telescopes (CT1-4), built in 2003, and a larger 28 m telescope (CT5), built in 2012. The larger mirror surface of CT5 permits to lower the energy threshold of the array down to 30 GeV. The cameras of CT1-4 are currently undergoing an extensive upgrade, with the goals of reducing their failure rate, reducing their readout dead time and improving the overall performance of the array. The entire camera electronics has been renewed from ground-up, as well as the power, ventilation and pneumatics systems, and the control and data acquisition software. Technical solutions forseen for the next-generation Cherenkov Telescope Array (CTA) observatory have been introduced, most notably the readout is based on the NECTAr analog memory chip. The camera control subsystems and the control software framework also pursue an innovative design, increasing the camera performance, robustness and flexibility. The CT1 camera has been upgraded in July 2015 and is currently taking data; CT2-4 will upgraded in Fall 2016. Together they will assure continuous operation of H.E.S.S at its full sensitivity until and possibly beyond the advent of CTA. This contribution describes the design, the testing and the in-lab and on-site performance of all components of the newly upgraded H.E.S.S. camera.

The Latest Results from the Focal L-Band Array for the Green Bank Telescope (FLAG), the World's (Current) Most Sensitive Phased Array Feed

NASA Astrophysics Data System (ADS)

Pingel, Nickolas; Pisano, D. J.

2018-01-01

Phased Array Feeds (PAFs) represent the next revolution in radio astronomy instrumentation. I will present results from the latest commissioning run from the Focal L-Band Array for the Green Bank telescope (FLAG), which holds the current world record for PAF sensitivity. Since we are able to operate at system temperatures comparable with the traditional GBT single pixel L-Band feed, the increase in the field-of-view provided by the beamforming capabilities of PAFs results in a dramatic (a factor of 5) increase in survey speeds. In particular, FLAG can probe similar neutral hydrogen column density regimes over a 4 sq. deg region in 24.6 minutes as opposed to 4.1 hours in an equivalent single pixel map (excluding observing overhead). In addition to comparisons between data taken with FLAG and the single-pixel L-Band feed, I will also discuss the technical aspects of the observing procedure, data reduction, and the transition path for FLAG from an instrument that is principle-investigator run to one that is general use. These FLAG results provide a very encouraging outlook on how the GBT will continue to compete with current and planned radio telescope facilities.

Submillimeter heterodyne spectroscopy of star forming regions

NASA Astrophysics Data System (ADS)

Groppi, Christopher Emil

The sub-mm wave portion of the electromagnetic spectrum is on the frontier of both scientific and technical research in astrophysics. Being a relatively young field, scientific advancement is driven by advancements in detector technology. In this thesis, I discuss the design, construction, testing and deployment of two sub-mm wave heterodyne array receivers. Polestar is a 4 pixel (2 x 2) heterodyne array built for operation in the 810 GHz atmospheric window. It is in operation at the AST/RO telescope at the South Pole. This receiver has increased imaging speed in this band at AST/RO by a factor of ˜20 compared to previous receiver systems. DesertStar is a 7 pixel, hexagonally close packed heterodyne array receiver built to operate in the 345 GHz atmospheric window at the Heinrich Hertz Telescope in Arizona. This system will be a facility instrument at the telescope, and will increase mapping speed over the existing dual polarization single beam receiver at the telescope now by a factor of ˜16. Both these receiver systems enable scientific projects requiring large area imaging that were previously impossible. I also discuss two scientific applications of sub-mm wave receiver systems. We have used multiple telescopes to observe several mm, sub-mm transitions and continuum emission towards the R CrA molecular cloud core. Originally thought to be associated with high mass star formation, we find that the driving source behind the mm-wave emission is a low mass protostar. The close proximity of R CrA allows us to achieve high spatial resolution even with single dish mm-wave and sub-mm wave telescopes. With this resolution, we are able to disentangle the effects of infall, rotation and outflow motions. We also use vibrationally excited HCN emission to probe the protostellar accretion disk in a sample of nearby high and low mass protostars of varying ages. While these observations are difficult with single dish telescopes, we show the promise of the technique, and report results on 4 sources.

The Telescope Array RADAR (TARA) Project and the Search for the Radar Signature of Cosmic Ray Induced Extensive Air Showers

NASA Astrophysics Data System (ADS)

Prohira, Steven; TARA Collaboration; Telescope Array Collaboration

2016-03-01

The TARA (Telescope Array Radar) cosmic ray detector has been in operation since May 2013. It is the most ambitious effort to date to test an idea that originated in the 1940's: that ionization produced by cosmic ray extensive air showers should reflect electromagnetic radiation. The observation of this effect would open the possibility that remote-sensing radar technology could be used to detect and reconstruct extensive air showers, thus increasing the aperture available for the study of the highest-energy cosmic rays. TARA employs a bi-static radar configuration, consisting of a 25 kW, 5 MW ERP transmitter at 54.1 MHz broadcasting across the Telescope Array surface detector. 40 km distant, a set of log-periodic receiver antennas are read out by two independent data acquisition systems employing different techniques to select signals of the form expected for radar targets moving at close to the speed of light. In this talk, we describe the TARA detector and present the first quantitative limits on the radar cross-section of extensive air showers.

Telescope Array UHECR composition measurement via stereoscopic fluorescence observation

NASA Astrophysics Data System (ADS)

Stroman, Thomas; Bergman, Douglas; Telescope Array Collaboration

2016-03-01

When entering Earth's atmosphere at ultra-high energies, cosmic rays (UHECRs) produce extensive air showers whose longitudinal development is influenced by the incident primary particle's mass. Each longitudinal shower profile reaches its maximum particle count at an atmospheric slant depth Xmax, and the distributions of observed Xmax values can be compared to those predicted by detailed simulations of the air-shower physics and the detector; accurately simulated compositions that most closely resemble that found in nature will produce the best agreement between predicted and observed Xmax distributions. This is the basis of composition measurement at the Telescope Array experiment, the largest and most sensitive UHECR detector in the northern hemisphere. At the perimeter of a large surface-detector array are three fluorescence telescope stations, whose overlapping apertures enable high-precision reconstruction of Xmax from stereoscopic observation of air-shower longitudinal profiles. We present the distribution of Xmax observed during eight years of operation, and from comparisons with several simulated combinations of composition and high-energy hadronic physics, we show that a low primary mass is favored at E >10 18 . 2 eV.

SODART telescopes on the Spectrum X-Gamma (SRG) and their complement of instruments

NASA Astrophysics Data System (ADS)

Schnopper, Herbert W.

1994-11-01

Two SODART thin foil X-ray telescopes will fly on SRG. In the focal plane of one telescope there are: HEPC/LEPC (high- and low energy imaging proportional counters), SIXA (solid state spectrometer array), and FRD (focal plane X-ray detector). In the other, there are: another HEPC/LEPC pair, SXRP (stellar X-ray polarimeter), and another FRD. Mounted alongside and co-aligned with the SODART telescopes is TAUVEX (UV telescope). An objective Bragg spectrometer is mounted in front of one of the telescopes. These instruments and their scientific goals will be described briefly. More detailed discussions will be given by the relevant PIs in the poster session.

A flat array large telescope concept for use on the moon, earth, and in space

NASA Technical Reports Server (NTRS)

Woodgate, Bruce E.

1991-01-01

An astronomical optical telescope concept is described which can provide very large collecting areas, of order 1000 sq m. This is an order of magnitude larger than the new generation of telescopes now being designed and built. Multiple gimballed flat mirrors direct the beams from a celestial source into a single telescope of the same aperture as each flat mirror. Multiple images of the same source are formed at the telescope focal plane. A beam combiner collects these images and superimposes them into a single image, onto a detector or spectrograph aperture. This telescope could be used on the earth, the moon, or in space.

Astronauts Akers and Thornton remove one of HST solar arrays during EVA

NASA Image and Video Library

1993-12-06

STS061-95-075 (6 Dec 1993) --- Astronauts Kathryn C. Thornton and Thomas D. Akers work to remove one of the solar arrays on the Hubble Space Telescope (HST) on the second of five extravehicular activity?s (EVA). The two space walkers later replaced both solar array panels. Part of Australia is in the background.

Ground-Based Telescope Parametric Cost Model

NASA Technical Reports Server (NTRS)

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.

Searches for Anisotropy of Cosmic Rays with the Telescope Array

NASA Astrophysics Data System (ADS)

Cady, Robert; Telescope Array Collaboration

2016-03-01

With over seven years of data from the TA surface detector array, we will present the results of various searches for anisotropies in the arrival direction of cosmic rays, including an update of the hotspot above 57 EeV.

Design and Performance of the Multiplexed SQUID/TES Array at Ninety Gigahertz

NASA Astrophysics Data System (ADS)

Stanchfield, Sara; Ade, Peter; Aguirre, James; Brevik, Justus A.; Cho, Hsiao-Mei; Datta, Rahul; Devlin, Mark; Dicker, Simon R.; Dober, Bradley; Duff, Shannon M.; Egan, Dennis; Ford, Pam; Hilton, Gene; Hubmayr, Johannes; Irwin, Kent; Knowles, Kenda; Marganian, Paul; Mason, Brian Scott; Mates, John A. B.; McMahon, Jeff; Mello, Melinda; Mroczkowski, Tony; Romero, Charles; Sievers, Jonathon; Tucker, Carole; Vale, Leila R.; Vissers, Michael; White, Steven; Whitehead, Mark; Ullom, Joel; Young, Alexander

2018-01-01

We present the array performance and astronomical images from early science results from MUSTANG-2, a 90 GHz feedhorn-coupled, microwave SQUID-multiplexed TES bolometer array operating on the Robert C. Byrd Green Bank Telescope (GBT). MUSTANG-2 was installed on the GBT on December 2, 2016 and immediately began commissioning efforts, followed by science observations, which are expected to conclude June 2017. The feedhorn and waveguide-probe-coupled detector technology is a mature technology, which has been used on instrument including the South Pole Telescope, the Atacama Cosmology Telescope, and the Atacama B-mode Search telescope. The microwave SQUID readout system developed for MUSTANG-2 currently reads out 66 detectors with a single coaxial cable and will eventually allow thousands of detectors to be multiplexed. This microwave SQUID multiplexer combines the proven abilities of millimeterwave TES detectors with the multiplexing capabilities of KIDs with no degradation in noise performance of the detectors. Each multiplexing device is read out using warm electronics consisting of a commercially available ROACH board, a DAC/ADC card, and an Intermediate Frequency mixer circuit. The hardware was originally developed by the UC Berkeley Collaboration for Astronomy Signal Processing and Electronic Research (CASPER) group, whose primary goal is to develop scalable FPGA-based hardware with the flexibility to be used in a wide range of radio signal processing applications. MUSTANG-2 is the first on-sky instrument to use microwave SQUID multiplexing and is available as a shared-risk/PI instrument on the GBT. In MUSTANG-2's first season 7 separate proposals were awarded a total of 230 hours of telescope time.

Detectors for the James Webb Space Telescope near-infrared spectrograph

NASA Astrophysics Data System (ADS)

Rauscher, Bernard J.; Figer, Donald F.; Regan, Michael W.; Boeker, Torsten; Garnett, James; Hill, Robert J.; Bagnasco, Giorgio; Balleza, Jesus; Barney, Richard; Bergeron, Louis E.; Brambora, Clifford; Connelly, Joe; Derro, Rebecca; DiPirro, Michael J.; Doria-Warner, Christina; Ericsson, Aprille; Glazer, Stuart D.; Greene, Charles; Hall, Donald N.; Jacobson, Shane; Jakobsen, Peter; Johnson, Eric; Johnson, Scott D.; Krebs, Carolyn; Krebs, Danny J.; Lambros, Scott D.; Likins, Blake; Manthripragada, Sridhar; Martineau, Robert J.; Morse, Ernie C.; Moseley, Samuel H.; Mott, D. Brent; Muench, Theo; Park, Hongwoo; Parker, Susan; Polidan, Elizabeth J.; Rashford, Robert; Shakoorzadeh, Kamdin; Sharma, Rajeev; Strada, Paolo; Waczynski, Augustyn; Wen, Yiting; Wong, Selmer; Yagelowich, John; Zuray, Monica

2004-10-01

The Near-Infrared Spectrograph (NIRSpec) is the James Webb Space Telescope"s primary near-infrared spectrograph. NASA is providing the NIRSpec detector subsystem, which consists of the focal plane array, focal plane electronics, cable harnesses, and software. The focal plane array comprises two closely-butted λco ~ 5 μm Rockwell HAWAII-2RG sensor chip assemblies. After briefly describing the NIRSpec instrument, we summarize some of the driving requirements for the detector subsystem, discuss the baseline architecture (and alternatives), and presents some recent detector test results including a description of a newly identified noise component that we have found in some archival JWST test data. We dub this new noise component, which appears to be similar to classical two-state popcorn noise in many aspects, "popcorn mesa noise." We close with the current status of the detector subsystem development effort.

Strategies for the follow-up of gravitational wave transients with the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Bartos, I.; Di Girolamo, T.; Gair, J. R.; Hendry, M.; Heng, I. S.; Humensky, T. B.; Márka, S.; Márka, Z.; Messenger, C.; Mukherjee, R.; Nieto, D.; O'Brien, P.; Santander, M.

2018-06-01

The observation of the electromagnetic counterpart of gravitational-wave (GW) transient GW170817 demonstrated the potential in extracting astrophysical information from multimessenger discoveries. The forthcoming deployment of the first telescopes of the Cherenkov Telescope Array (CTA) observatory will coincide with Advanced LIGO/Virgo's next observing run, O3, enabling the monitoring of gamma-ray emission at E > 20 GeV, and thus particle acceleration, from GW sources. CTA will not be greatly limited by the precision of GW localization as it will be capable of rapidly covering the GW error region with sufficient sensitivity. We examine the current status of GW searches and their follow-up effort, as well as the status of CTA, in order to identify some of the general strategies that will enhance CTA's contribution to multimessenger discoveries.

Experimental instrumentation system for the Phased Array Mirror Extendible Large Aperture (PAMELA) test program

NASA Technical Reports Server (NTRS)

Boykin, William H., Jr.

1993-01-01

Adaptive optics are used in telescopes for both viewing objects with minimum distortion and for transmitting laser beams with minimum beam divergence and dance. In order to test concepts on a smaller scale, NASA MSFC is in the process of setting up an adaptive optics test facility with precision (fraction of wavelengths) measurement equipment. The initial system under test is the adaptive optical telescope called PAMELA (Phased Array Mirror Extendible Large Aperture). Goals of this test are: assessment of test hardware specifications for PAMELA application and the determination of the sensitivities of instruments for measuring PAMELA (and other adaptive optical telescopes) imperfections; evaluation of the PAMELA system integration effort and test progress and recommended actions to enhance these activities; and development of concepts and prototypes of experimental apparatuses for PAMELA.

HST Solar Arrays photographed by Electronic Still Camera

NASA Image and Video Library

1993-12-04

S61-E-002 (4 Dec 1993) --- This view, backdropped against the blackness of space shows one of two original Solar Arrays (SA) on the Hubble Space Telescope (HST). The scene was photographed from inside Endeavour's cabin with an Electronic Still Camera (ESC), and down linked to ground controllers soon afterward. This view features the minus V-2 panel. Endeavour's crew captured the HST on December 4, 1993 in order to service the telescope over a period of five days. Four of the crew members will work in alternating pairs outside Endeavour's shirt sleeve environment to service the giant telescope. Electronic still photography is a relatively new technology which provides the means for a handheld camera to electronically capture and digitize an image with resolution approaching film quality. The electronic still camera has flown as an experiment on several other shuttle missions.

HST Solar Arrays photographed by Electronic Still Camera

NASA Image and Video Library

1993-12-04

S61-E-003 (4 Dec 1993) --- This medium close-up view of one of two original Solar Arrays (SA) on the Hubble Space Telescope (HST) was photographed with an Electronic Still Camera (ESC), and down linked to ground controllers soon afterward. This view shows the cell side of the minus V-2 panel. Endeavour's crew captured the HST on December 4, 1993 in order to service the telescope over a period of five days. Four of the crew members will work in alternating pairs outside Endeavour's shirt sleeve environment to service the giant telescope. Electronic still photography is a relatively new technology which provides the means for a handheld camera to electronically capture and digitize an image with resolution approaching film quality. The electronic still camera has flown as an experiment on several other shuttle missions.

EVA 2 - old solar array installed in payload bay

NASA Image and Video Library

2002-03-05

STS109-326-008 (5 March 2002) --- Astronaut Michael J. Massimino, mission specialist, works at the stowage area for the Hubble Space Telescope's port side solar array. Astronauts Massimino and James H. Newman removed the old port solar array and stowed it in Columbia’s payload bay for a return to Earth. They then went on to install a third-generation solar array and its associated electrical components. Two crew mates had accomplished the same feat with the starboard array on the previous day.

A parametric study of various synthetic aperture telescope configurations for coherent imaging applications

NASA Technical Reports Server (NTRS)

Harvey, James E.; Wissinger, Alan B.; Bunner, Alan N.

1986-01-01

The comparative advantages of synthetic aperture telescopes (SATs) of segmented primary mirror and common secondary mirror type, on the one hand, and on the other those employing an array of independent telescopes, are discussed. The diffraction-limited optical performance of both redundant and nonredundant subaperture configurations are compared in terms of point spread function characteristics and encircled energy plots. Coherent imaging with afocal telescope SATs involves a pupil-mapping operation followed by a Fourier transform one. A quantitative analysis of the off-axis optical performance degradation due to pupil-mapping errors is presented, together with the field-dependent effects of residual design aberrations of independent telescopes.

Cryogenic Optical Performance of the Cassini Composite InfraRed Spectrometer (CIRS) Flight Telescope

NASA Technical Reports Server (NTRS)

Losch, Patricia; Lyons, James J., III; Hagopian, John

1998-01-01

The CIRS half-meter diameter beryllium flight telescope's optical performance was tested at the instrument operating temperature of 170 Kelvin. The telescope components were designed at Goddard Space Flight Center (GSFC) but fabricated out of house and then assembled, aligned and tested upon receipt at GSFC. A 24 inch aperture cryogenic test facility utilizing a 1024 x 1024 CCD array was developed at GSFC specifically for this test. The telescope,s image quality (measured as encircled energy), boresight stability and focus stability were measured. The gold coated beryllium design exceeded the cold image performance requirement of 80% encircled energy within a 460 micron diameter circle.

TIRGO and its instrumentation

NASA Astrophysics Data System (ADS)

Baffa, Carlo; Gennari, Sandro; Hunt, Leslie K.; Lisi, Franco; Tofani, Gianni; Vanzi, Leonardo

1995-09-01

We describe the general characteristics of the TIRGO infrared telescope, located on Gornergrat (Switzerland), and its most recent instrumentation. This telescope is specifically designed for infrared astronomical observations. Two newly designed instruments are presented: the imaging camera Arnica and the long-slit spectrometer LonGSp, both based on two-dimensional array detectors.

Nobeyama Radio Observatory

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Nobeyama Radio Observatory has telescopes at millimeter and submillimeter wavelengths. It was established in 1982 as an observatory of Tokyo Astronomical Observatory (NATIONAL ASTRONOMICAL OBSERVATORY, JAPAN since 1987), and operates the 45 m telescope, Nobeyama Millimeter Array, and Radioheliograph. High-resolution images of star forming regions and molecular clouds have revealed many aspects of...

A second fast radio burst discovered with Parkes Telescope within 50 hours: FRB180311 in the direction of PSR J2129-5721

NASA Astrophysics Data System (ADS)

Oslowski, S.; Shannon, R. M.; Jameson, Andrew; Hobbs, G.; Bailes, M.; Bhat, N. D. R.; Coles, W. A.; Dai, S.; Dempsey, J.; Keith, M. J.; Kerr, M.; Manchester, R. N.; Lasky, D. P.; Levin, Y.; Parthasarathy, A.; Ravi, V.; Reardon, D. J.; Russell, C. J.; Sarkissian, J. M.; Spiewak, R.; Van Straten, W.; Toomey, L.; Wang, J. B.; Wen, L.; You, X.-P.; Zhang, L.; Zhang, S.; Zhu, X.-J.

2018-03-01

The Parkes Pulsar Timing Array (Manchester et al. 2013) project monitors pulse times of arrival for 24 millisecond pulsars in the Galaxy on a fortnightly cadence using the multibeam receiver on the CSIRO 64-m Parkes Telescope.

Hubble Space Telescope solar cell module thermal cycle test

NASA Technical Reports Server (NTRS)

Douglas, Alexander; Edge, Ted; Willowby, Douglas; Gerlach, Lothar

1992-01-01

The Hubble Space Telescope (HST) solar array consists of two identical double roll-out wings designed after the Hughes flexible roll-up solar array (FRUSA) and was developed by the European Space Agency (ESA) to meet specified HST power output requirements at the end of 2 years, with a functional lifetime of 5 years. The requirement that the HST solar array remain functional both mechanically and electrically during its 5-year lifetime meant that the array must withstand 30,000 low Earth orbit (LEO) thermal cycles between approximately +100 and -100 C. In order to evaluate the ability of the array to meet this requirement, an accelerated thermal cycle test in vacuum was conducted at NASA's Marshall Space Flight Center (MSFC), using two 128-cell solar array modules which duplicated the flight HST solar array. Several other tests were performed on the modules. The thermal cycle test was interrupted after 2,577 cycles, and a 'cold-roll' test was performed on one of the modules in order to evaluate the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit. A posttest static shadow test was performed on one of the modules in order to analyze temperature gradients across the module. Finally, current in-flight electrical performance data from the actual HST flight solar array will be tested.

C-STARS Baltimore Simulation Center Military Trauma Training Program: Training for High Performance Trauma Teams

DTIC Science & Technology

2013-09-19

for October 2010 to September 2013 Air Force Research Laboratory 711th Human Performance Wing School of Aerospace Medicine Air Force...WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) USAF School of Aerospace Medicine Air Force Expeditionary Medical Skills...Patient denies any performance enhancers or herbal use. BP – 110/68, P 124, R –28 shallow, and sweating from exercise. Patient states he never

High Resolution Near-Bed Observations in Winter Near Cape Hatteras, North Carolina

DTIC Science & Technology

2010-06-01

Druck pressure sensors, Campbell optical backscatter, and Seatech or Wetlabs CSTAR transmission sensors. All the transmissometers were 25 cm path...14.0 m Depth Flobee Tripods Sontek hydra Acoustic Doppler velocimeter (ADV), thermistor 3D flow velocity, temperature 8 Hz for 17.5 min hourly Pulse...coherent acoustic Doppler profiler (PCADP), thermistor Profiles of 3D flow velocity, temperature 1 Hz for 17.5 min hourly, 6.3 cm bins Pressure

Center for Space Transportation and Applied Research Fifth Annual Technical Symposium Proceedings

NASA Technical Reports Server (NTRS)

1993-01-01

This Fifth Annual Technical Symposium, sponsored by the UT-Calspan Center for Space Transportation and Applied Research (CSTAR), is organized to provide an overview of the technical accomplishments of the Center's five Research and Technology focus areas during the past year. These areas include chemical propulsion, electric propulsion, commerical space transportation, computational methods, and laser materials processing. Papers in the area of artificial intelligence/expert systems are also presented.

Wide-Field-of-View Millimeter-Wave Telescope Design with Ultra-Low Cross-Polarization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernacki, Bruce E.; Kelly, James F.; Sheen, David M.

2012-05-01

As millimeter-wave arrays become available, off-axis imaging performance of the fore optics increases in importance due to the relatively large physical extent of the arrays. Typically, simple optical telescope designs are adapted to millimeter-wave imaging but single-mirror spherical or classic conic designs cannot deliver adequate image quality except near the optical axis. Since most millimeter-wave designs are quasi-optical, optical ray tracing and commercial design software can be used to optimize designs to improve off-axis imaging as well as minimize cross-polarization. Methods that obey the Dragone-Mizuguchi condition for the design of reflective millimeter-wave telescopes with low cross-polarization also provide additional degreesmore » of freedom that offer larger fields of view than possible with single-reflector designs. Dragone’s graphical design method does not lend itself readily to computer-based optical design approaches, but subsequent authors expanded on Dragone’s geometric design approach with analytic expressions that describe the location, shape, off-axis height and tilt of the telescope elements that satisfy Dragone’s design rules and can be used as a first-order design for subsequent computer-based design and optimization. We investigate two design variants that obey the Dragone-Mizuguchi conditions that exhibit ultra-low polarization crosstalk and a large diffraction-limited field of view well suited to millimeter-wave imaging arrays.« less

Integrated infrared detector arrays for low-background applications

NASA Technical Reports Server (NTRS)

Mccreight, C. R.; Goebel, J. H.

1982-01-01

Advanced infrared detector and detector array technology is being developed and characterized for future NASA space astronomy applications. Si:Bi charge-injection-device arrays have been obtained, and low-background sensitivities comparable to that of good discrete detectors have been measured. Intrinsic arrays are being assessed, and laboratory and telescope data have been collected on a monolithic InSb CCD array. For wavelengths longer than 30 microns, improved Ge:Ga detectors have been produced, and steps have been taken to prove the feasibility of an integrated extrinsic germanium array. Other integrated arrays and cryogenic components are also under investigation.

Proceedings of the Second Infrared Detector Technology Workshop

NASA Technical Reports Server (NTRS)

Mccreight, C. R. (Compiler)

1986-01-01

The workshop focused on infrared detector, detector array, and cryogenic electronic technologies relevant to low-background space astronomy. Papers are organized into the following categories: discrete infrared detectors and readout electronics; advanced bolometers; intrinsic integrated infrared arrays; and extrinsic integrated infrared arrays. Status reports on the Space Infrared Telescope Facility (SIRTF) and Infrared Space Observatory (ISO) programs are also included.

Comparative efficiency analysis of fiber-array and conventional beam director systems in volume turbulence.

PubMed

Vorontsov, Mikhail; Filimonov, Grigory; Ovchinnikov, Vladimir; Polnau, Ernst; Lachinova, Svetlana; Weyrauch, Thomas; Mangano, Joseph

2016-05-20

The performance of two prominent laser beam projection system types is analyzed through wave-optics numerical simulations for various atmospheric turbulence conditions, propagation distances, and adaptive optics (AO) mitigation techniques. Comparisons are made between different configurations of both a conventional beam director (BD) using a monolithic-optics-based Cassegrain telescope and a fiber-array BD that uses an array of densely packed fiber collimators. The BD systems considered have equal input power and aperture diameters. The projected laser beam power inside the Airy size disk at the target plane is used as the performance metric. For the fiber-array system, both incoherent and coherent beam combining regimes are considered. We also present preliminary results of side-by-side atmospheric beam projection experiments over a 7-km propagation path using both the AO-enhanced beam projection system with a Cassegrain telescope and the coherent fiber-array BD composed of 21 densely packed fiber collimators. Both wave-optics numerical simulation and experimental results demonstrate that, for similar system architectures and turbulence conditions, coherent fiber-array systems are more efficient in mitigation of atmospheric turbulence effects and generation of a hit spot of the smallest possible size on a remotely located target.

Recent results from the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Abbasi, Rasha; Telescope Array Collaboration

2016-03-01

The Telescope Array (TA) is the largest ultrahigh energy cosmic rays detector in the northern hemisphere. TA is a hybrid detector comprised of three air fluorescence stations and a large surface array consisting of 507 scintillator counters. Each of the three fluorescence stations, located at the periphery of the ground array, views 108 degrees in azimuth and up to 30 degrees in elevation. The surface detectors are arranged in a square grid of 1.2 km spacing, covering over 700 square kilometers. TA has collected more than seven years of data. In this talk, we will present some of the main results on the cosmic rays composition and energy spectrum obtained by TA and its low energy extension (TALE). Finally, we will present our results from the search for arrival direction anisotropy, including the observed large excess of events at the highest energies, seen in the region of the northern sky centered on Ursa Major. Based on the current results, the ``hot spot'' in particular, TA is pursuing the expansion of the surface array to four times its current size.

Cherenkov Telescope Array: the next-generation gamma ray observatory

NASA Astrophysics Data System (ADS)

Ebr, Jan

2017-08-01

The Cherenkov Telescope Array (CTA) is a project to build the next generation ground-based observatory for gamma-ray astronomy at very-high energies in the range from 20 GeV to 300 TeV, which will both surpass the sensitivity of existing instruments in their energy domains and extend the limits of the observed energy spectrum. It will probe some of the most energetic processes in the Universe and provide insight into topics such as the acceleration of charged cosmic rays and their role in galaxy evolution, processes in relativistic jets, wind and explosions and the nature and distribution of dark matter. The CTA Observatory will consist of more than a hundred imaging atmospheric Cherenkov telescopes (IACT) of three different size classes, installed at two premier astronomical locations, one in each hemisphere. It is foreseen that the telescopes will use a variety of optical designs including parabolic primary mirrors, variations of the Davies-Cotton design and two-mirror setups such as the Schwarzschild-Couder telescope, and several camera designs, using both photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs) for detection of the nanosecond-scale Cherenkov flashes. Each telescope will feature a precise but lightweight and agile mount, allowing even the largest telescopes to change targets within 20 seconds, with systems of sensors and actuators actively controlling the shape of the reflecting surfaces. As an integral part, the Observatory will feature extensive calibration facilities, closely monitoring both the detectors themselves and the surrounding atmosphere. Several telescope prototypes already exist and the installation works at the northern site have started.

A 1.2m Deployable, Transportable Space Surveillance Telescope Designed to Meet AF Space Situational Awareness Needs

NASA Astrophysics Data System (ADS)

McGraw, J.; Ackermann, M.

Recent years have seen significant interest in optical-infrared (OIR) space surveillance capabilities to complement and supplement radar-based sensors. To address this legitimate need for OIR sensors, the Air Force Research Laboratory has been working on several projects intended to meet SSA requirements in practical, fieldable and affordable packages. In particular, while the PanStarrs system is primarily an astronomy project, their well-designed telescope(s) will have substantial SSA capability, but the system, based on four 1.8m apertures on the same mount, will be a fixed location asset. For world-wide deployment, we are studying a smaller "PanStarrs derived" system which would be replicable and inexpensive. A fixed set of telescope arrays would provide substantial SSA search and monitor capability. These telescopes are also designed to be deployed in pairs in a standard cargo container package for theater SSA. With a 1.2m aperture and a 4.5deg FOV, each telescope would have the same etendue as its big brother PanStarrs telescope, but with image quality optimized for space surveillance rather than astronomy. The telescope is even scaled to use production PanStarrs focal plane arrays. A single 1.2m system has almost the same search rate for dim targets as any other system in development. Two such telescopes working together will exceed the performance of any SSA asset either in production or on the drawing boards. Because they are small they can be designed to be replicable and inexpensive and thus could be abandoned in place should the political climate at their deployment sites change for the worse.

RAPTOR: Closed-Loop monitoring of the night sky and the earliest optical detection of GRB 021211

NASA Astrophysics Data System (ADS)

Vestrand, W. T.; Borozdin, K.; Casperson, D. J.; Fenimore, E.; Galassi, M.; McGowan, K.; Starr, D.; White, R. R.; Wozniak, P.; Wren, J.

2004-10-01

We discuss the RAPTOR (Rapid Telescopes for Optical Response) sky monitoring system at Los Alamos National Laboratory. RAPTOR is a fully autonomous robotic system that is designed to identify and make follow-up observations of optical transients with durations as short as one minute. The RAPTOR design is based on Biomimicry of Human Vision. The sky monitor is composed of two identical arrays of telescopes, separated by 38 kilometers, which stereoscopically monitor a field of about 1300 square-degrees for transients. Both monitoring arrays are carried on rapidly slewing mounts and are composed of an ensemble of wide-field telescopes clustered around a more powerful narrow-field telescope called the ``fovea'' telescope. All telescopes are coupled to real-time analysis pipelines that identify candidate transients and relay the information to a central decision unit that filters the candidates to find real celestial transients and command a response. When a celestial transient is found, the system can point the fovea telescopes to any position on the sky within five seconds and begin follow-up observations. RAPTOR also responds to Gamma Ray Burst (GRB) alerts generated by GRB monitoring spacecraft. Here we present RAPTOR observations of GRB 021211 that constitute the earliest detection of optical emission from that event and are the second fastest achieved for any GRB. The detection of bright optical emission from GRB021211, a burst with modest gamma-ray fluence, indicates that prompt optical emission, detectable with small robotic telescopes, is more common than previously thought. Further, the very fast decline of the optical afterglow from GRB 021211 suggests that some so-called ``optically dark'' GRBs were not detected only because of the slow response of the follow-up telescopes.

Metrology System for a Large, Somewhat Flexible Telescope

NASA Technical Reports Server (NTRS)

Liebe, Carl Christian; Bartman, Randall; Cook, Walter; Craig, William

2009-01-01

A proposed metrology system would be incorporated into a proposed telescope that would include focusing optics on a rigid bench connected via a deployable mast to another rigid bench holding a focal-plane array of photon counting photodetectors. Deformations of the deployable mast would give rise to optical misalignments that would alter the directions (and, hence, locations) of incidence of photons on the focal plane. The metrology system would measure the relative displacement of the focusing- optics bench and the focal-plane array bench. The measurement data would be used in post-processing of the digitized photodetector outputs to compensate for the mast-deformation-induced changes in the locations of incidence of photons on the focal plane, thereby making it possible to determine the original directions of incidence of photons with greater accuracy. The proposed metrology system is designed specifically for the Nuclear Spectroscopic Telescope Array (NuSTAR) a proposed spaceborne x-ray telescope. The basic principles of design and operation are also applicable to other large, somewhat flexible telescopes, both terrestrial and spaceborne. In the NuSTAR, the structural member connecting the optical bench and the photodetector array would be a 10-m-long deployable mast, and there is a requirement to keep errors in measured directions of incidence of photons below 10 arc seconds (3 sigma). The proposed system would include three diode lasers that would be mounted on the focusing-optics bench. For clarity, only one laser is shown in the figure, which is a greatly simplified schematic diagram of the system. Each laser would be aimed at a position-sensitive photodiode that would be mounted on the detector bench alongside the aforementioned telescope photodetector array. The diode lasers would operate at a wavelength of 830 nm, each at a power of 200 mW. Each laser beam would be focused to a spot of .1-mm diameter on the corresponding position-sensitive photodiode. To reduce the effect of sunlight on the measurements, a one-stage light baffle and an 830-nm transmission filter of 10-nm bandwidth would be placed in front of the position- sensitive photodiode. For each metrology reading, the output of the position-sensitive detector would be sampled and digitized twice: once with the lasers turned on, then once with the lasers turned off. The data from these two sets of samples would be subtracted from each other to further reduce the effects of sun glints or other background light sources.

Numerical simulations of imaging satellites with optical interferometry

NASA Astrophysics Data System (ADS)

Ding, Yuanyuan; Wang, Chaoyan; Chen, Zhendong

2015-08-01

Optical interferometry imaging system, which is composed of multiple sub-apertures, is a type of sensor that can break through the aperture limit and realize the high resolution imaging. This technique can be utilized to precisely measure the shapes, sizes and position of astronomical objects and satellites, it also can realize to space exploration and space debris, satellite monitoring and survey. Fizeau-Type optical aperture synthesis telescope has the advantage of short baselines, common mount and multiple sub-apertures, so it is feasible for instantaneous direct imaging through focal plane combination.Since 2002, the researchers of Shanghai Astronomical Observatory have developed the study of optical interferometry technique. For array configurations, there are two optimal array configurations proposed instead of the symmetrical circular distribution: the asymmetrical circular distribution and the Y-type distribution. On this basis, two kinds of structure were proposed based on Fizeau interferometric telescope. One is Y-type independent sub-aperture telescope, the other one is segmented mirrors telescope with common secondary mirror.In this paper, we will give the description of interferometric telescope and image acquisition. Then we will mainly concerned the simulations of image restoration based on Y-type telescope and segmented mirrors telescope. The Richardson-Lucy (RL) method, Winner method and the Ordered Subsets Expectation Maximization (OS-EM) method are studied in this paper. We will analyze the influence of different stop rules too. At the last of the paper, we will present the reconstruction results of images of some satellites.

Innovative research in the design and operation of large telescopes for space: Aspects of giant telescopes in space

NASA Technical Reports Server (NTRS)

Angel, J. R. P.

1985-01-01

The capability and understanding of how to finish the reflector surfaces needed for large space telescopes is discussed. The technology for making very light glass substrates for mirrors is described. Other areas of development are in wide field imaging design for very fast primaries, in data analysis and retrieval methods for astronomical images, and in methods for making large area closely packed mosaics of solid state array detectors.

Multivariable Parametric Cost Model for Ground Optical Telescope Assembly

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Rowell, Ginger Holmes; Reese, Gayle; Byberg, Alicia

2005-01-01

A parametric cost model for ground-based telescopes is developed using multivariable statistical analysis of both engineering and performance parameters. While diameter continues to be the dominant cost driver, diffraction-limited wavelength is found to be a secondary driver. Other parameters such as radius of curvature are examined. 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.

CHARA/FLUOR updates and performance

NASA Astrophysics Data System (ADS)

Mérand, Antoine; Coudé du Foresto, Vincent; Kellerer, Aglaé; ten Brummelaar, Theo; Reess, Jean-Michel; Ziegler, Denis

2006-06-01

In 2002, the Fiber Linked Unit for Optical Recombination (FLUOR) has been moved from the Infrared Optical Telescope Array (IOTA) to the CHARA Array. We present here the main upgrades that followed the installation, the new features installed, including spectral dispersion, and the current capabilities of the instrument.

Facility Instrumentation for SOFIA: Technical Specifications and Scientific Goals

NASA Astrophysics Data System (ADS)

Stacey, G. J.

2000-05-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is NASA's next generation airborne observatory consisting of a 2.5 m telescope in a modified Boeing 747 SP. First light is expected in late 2002. Three "Facility Class" instruments were among the first generation of instruments selected to fly on SOFIA. These instruments, currently under development are (1) a 5 to 38 um imaging photometer based on twin As:Si and Sb:Sb BIB arrays (FORCAST), (2) a 40 to 300 um photometer based on three arrays of bolometers, and (3) a 17 to 210 um eschelle grating spectrometer based on an Sb:Sb BIB array and a Ge:Sb and stressed Ge:Ga array of photoconductors. I will discuss both the technical aspects of these facility instruments, and some of the exciting new science that is possible with these ground breaking instruments on an airborne 2.5 meter telescope. Science topics include circumstellar debris disks, star formation, the Galactic Center, and distant galaxies.

Metallized Gelled Propellants: Oxygen/RP-1/Aluminum Rocket Heat Transfer and Combustion Measurements

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan; Zakany, James S.

1996-01-01

A series of rocket engine heat transfer experiments using metallized gelled liquid propellants was conducted. These experiments used a small 20- to 40-lb/f thrust engine composed of a modular injector, igniter, chamber and nozzle. The fuels used were traditional liquid RP-1 and gelled RP-1 with 0-, 5-, and 55-percentage by weight loadings of aluminum particles. Gaseous oxygen was used as the oxidizer. Three different injectors were used during the testing: one for the baseline O(2)/RP-1 tests and two for the gelled and metallized gelled fuel firings. Heat transfer measurements were made with a rocket engine calorimeter chamber and nozzle with a total of 31 cooling channels. Each chamber used a water flow to carry heat away from the chamber and the attached thermocouples and flow meters allowed heat flux estimates at each of the 31 stations. The rocket engine Cstar efficiency for the RP-1 fuel was in the 65-69 percent range, while the gelled 0 percent by weight RP-1 and the 5-percent by weight RP-1 exhibited a Cstar efficiency range of 60 to 62% and 65 to 67%, respectively. The 55-percent by weight RP-1 fuel delivered a 42-47% Cstar efficiency. Comparisons of the heat flux and temperature profiles of the RP-1 and the metallized gelled RP-1/A1 fuels show that the peak nozzle heat fluxes with the metallized gelled O2/RP-1/A1 propellants are substantially higher than the baseline O2/RP-1: up to double the flux for the 55 percent by weight RP-1/A1 over the RP-1 fuel. Analyses showed that the heat transfer to the wall was significantly different for the RP-1/A1 at 55-percent by weight versus the RP-1 fuel. Also, a gellant and an aluminum combustion delay was inferred in the 0 percent and 5-percent by weight RP-1/A1 cases from the decrease in heat flux in the first part of the chamber. A large decrease in heat flux in the last half of the chamber was caused by fuel deposition in the chamber and nozzle. The engine combustion occurred well downstream of the injector face based on the heat flux estimates from the temperature measurements.

The energy spectrum of cosmic rays above 1017.2 eV measured by the fluorescence detectors of the Telescope Array experiment in seven years

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2016-07-01

The Telescope Array (TA) experiment is the largest detector to observe ultra-high-energy cosmic rays in the northern hemisphere. The fluorescence detectors at two stations of TA are newly constructed and have now completed seven years of steady operation. One advantage of monocular analysis of the fluorescence detectors is a lower energy threshold for cosmic rays than that of other techniques like stereoscopic observations or coincidences with the surface detector array, allowing the measurement of an energy spectrum covering three orders of magnitude in energy. Analyzing data collected during those seven years, we report the energy spectrum of cosmic rays covering a broad range of energies above 1017.2eV measured by the fluorescence detectors and a comparison with previously published results.

The Navy Precision Optical Interferometer: an update

NASA Astrophysics Data System (ADS)

Armstrong, J. T.; Baines, Ellyn K.; Schmitt, Henrique R.; Restaino, Sergio R.; Clark, James H.; Benson, James A.; Hutter, Donald J.; Zavala, Robert T.; van Belle, Gerard T.

2016-08-01

We describe the current status of the Navy Precision Optical Interferometer (NPOI), including developments since the last SPIE meeting. The NPOI group has added stations as far as 250m from the array center and added numerous infrastructure improvements. Science programs include stellar diameters and limb darkening, binary orbits, Be star disks, exoplanet host stars, and progress toward high-resolution stellar surface imaging. Technical and infrastructure projects include on-sky demonstrations of baseline bootstrapping with six array elements and of the VISION beam combiner, control system updates, integration of the long delay lines, and updated firmware for the Classic beam combiner. Our plans to add up to four 1.8 m telescopes are no longer viable, but we have recently acquired separate funding for adding three 1 m AO-equipped telescopes and an infrared beam combiner to the array.

The UV Survey Mission Concept, CETUS

NASA Astrophysics Data System (ADS)

Heap, Sara; and the CETUS Team

2018-01-01

In March 2017, NASA selected CETUS for study of a Probe-class mission concept. W. Danchi is the CETUS PI, and S. Heap is the Science PI. CETUS is primarily a UV survey telescope to complement survey telescopes of the 2020’s including E-ROSITA, Subaru Hyper Suprime Cam and Prime-Focus Spectrograph, WFIRST, and the Square Kilometer Array. CETUS comprises a 1.5-m wide-field telescope and three science instruments: a wide-field (1045” on a side) far-UV and near-UV camera; a similarly wide-field near-UV multi-object spectrograph utilizing a next-generation micro-shutter array; and a single-object spectrograph with options of spectral region (far-UV or near-UV) and spectral resolving power (2,000 or 40,000). The survey instruments will operate simultaneously thereby producing wide-field images in the near-UV and far-UV and a spectrogram containing near-UV spectra of up to 100 sources free of spectral overlap and astronomical background. ln concert with other survey telescopes, CETUS will focus on understanding galaxy evolution at cosmic noon (z~1-2).

SIRTF, the Space Infrared Telescope Facility

NASA Technical Reports Server (NTRS)

Simmons, Larry L.

1999-01-01

The Space Infrared Telescope Facility (SIRTF) is the last of the NASA Great Observatories, and a cornerstone of the NASA Origins Missions. The Observatory will include an 85 cm telescope in a unique orbit around the sun. The telescope will be launched at ambient temperature and cooled to 5.5K in space. The science instruments will use large detector arrays that will be background limited, and capable of a broad range of astrophysical investigations. The SIRTF architecture will accommodate up to 5 years of cryogenic space operations. This talk will describe both the scientific and technical capabilities of SIRTF.

Requirements and concept design for large earth survey telescope for SEOS

NASA Technical Reports Server (NTRS)

Mailhot, P.; Bisbee, J.

1975-01-01

The efforts of a one year program of Requirements Analysis and Conceptual Design for the Large Earth Survey Telescope for the Synchronous Earth Observatory Satellite is summarized. A 1.4 meter aperture Cassegrain telescope with 0.6 deg field of view is shown to do an excellent job in satisfying the observational requirements for a wide range of earth resources and meteorological applications. The telescope provides imagery or thermal mapping in ten spectral bands at one time in a field sharing grouping of linear detector arrays. Pushbroom scanning is accomplished by spacecraft slew.

A CCD experimental platform for large telescope in Antarctica based on FPGA

NASA Astrophysics Data System (ADS)

Zhu, Yuhua; Qi, Yongjun

2014-07-01

The CCD , as a detector , is one of the important components of astronomical telescopes. For a large telescope in Antarctica, a set of CCD detector system with large size, high sensitivity and low noise is indispensable. Because of the extremely low temperatures and unattended, system maintenance and software and hardware upgrade become hard problems. This paper introduces a general CCD controller experiment platform, using Field programmable gate array FPGA, which is, in fact, a large-scale field reconfigurable array. Taking the advantage of convenience to modify the system, construction of driving circuit, digital signal processing module, network communication interface, control algorithm validation, and remote reconfigurable module may realize. With the concept of integrated hardware and software, the paper discusses the key technology of building scientific CCD system suitable for the special work environment in Antarctica, focusing on the method of remote reconfiguration for controller via network and then offering a feasible hardware and software solution.

VizieR Online Data Catalog: Galactic HII region IRAS 16148-5011 content (Mallick+, 2015)

NASA Astrophysics Data System (ADS)

Mallick, K. K.; Ojha, D. K.; Tamura, M.; Linz, H.; Samal, M. R.; Ghosh, S. K.

2015-11-01

NIR photometric observations in J (1.25um), H (1.63um), and Ks (2.14um) bands (centred on RA=16:18:31, DE=-50:17:32 (2000)) were carried out on 2004 July 29 using the 1.4m Infrared Survey Facility (IRSF) telescope, South Africa. The observations were taken with the help of the Simultaneous InfraRed Imager for Unbiased Survey (SIRIUS) instrument, a three colour simultaneous camera mounted at the f/10 Cassegrain focus of the telescope. Radio continuum observations at 1280MHz were obtained on 2012 November 09 using the Giant Metrewave Radio Telescope (GMRT) array. The GMRT array consists of 30 antennas arranged in an approximate Y-shaped configuration, with each antenna having a diameter of 45m. This translates to a primary beam-size of 26.2-arcmin at 1280MHz. (2 data files).

An Integrated Optimal Estimation Approach to Spitzer Space Telescope Focal Plane Survey

NASA Technical Reports Server (NTRS)

Bayard, David S.; Kang, Bryan H.; Brugarolas, Paul B.; Boussalis, D.

2004-01-01

This paper discusses an accurate and efficient method for focal plane survey that was used for the Spitzer Space Telescope. The approach is based on using a high-order 37-state Instrument Pointing Frame (IPF) Kalman filter that combines both engineering parameters and science parameters into a single filter formulation. In this approach, engineering parameters such as pointing alignments, thermomechanical drift and gyro drifts are estimated along with science parameters such as plate scales and optical distortions. This integrated approach has many advantages compared to estimating the engineering and science parameters separately. The resulting focal plane survey approach is applicable to a diverse range of science instruments such as imaging cameras, spectroscopy slits, and scanning-type arrays alike. The paper will summarize results from applying the IPF Kalman Filter to calibrating the Spitzer Space Telescope focal plane, containing the MIPS, IRAC, and the IRS science Instrument arrays.

Space astronomical telescopes and instruments; Proceedings of the Meeting, Orlando, FL, Apr. 1-4, 1991

NASA Astrophysics Data System (ADS)

Bely, Pierre Y.; Breckinridge, James B.

The present volume on space astronomical telescopes and instruments discusses lessons from the HST, telescopes on the moon, future space missions, and mirror fabrication and active control. Attention is given to the in-flight performance of the Goddard high-resolution spectrograph of the HST, the initial performance of the high-speed photometer, results from HST fine-guidance sensors, and reconstruction of the HST mirror figure from out-of-focus stellar images. Topics addressed include system concepts for a large UV/optical/IR telescope on the moon, optical design considerations for next-generation space and lunar telescopes, the implications of lunar dust for astronomical observatories, and lunar liquid-mirror telescopes. Also discussed are space design considerations for the Space Infrared Telescope Facility, the Hubble extrasolar planet interferometer, Si:Ga focal-plane arrays for satellite and ground-based telescopes, microchannel-plate detectors for space-based astronomy, and a method for making ultralight primary mirrors.

The Australian SKA Pathfinder: operations management and user engagement

NASA Astrophysics Data System (ADS)

Harvey-Smith, Lisa

2016-07-01

This paper describes the science operations model for the Australian Square Kilometre Array Pathfinder (ASKAP) telescope. ASKAP is a radio interferometer currently being commissioned in Western Australia. It will be operated by a dedicated team of observatory staff with the support of telescope monitoring, control and scheduling software. These tools, as well as the proposal tools and data archive will enable the telescope to operate with little direct input from the astronomy user. The paper also discusses how close engagement with the telescope user community has been maintained throughout the ASKAP construction and commissioning phase, leading to positive outcomes including early input into the design of telescope systems and a vibrant early science program.

The Marshall Space Flight Center Development of Mirror Modules for the ART-XC Ins1rument Aboard the Spectrum-Roentgen-Gamma Mission

NASA Technical Reports Server (NTRS)

Gubarev, M.; Ramsey, B.; ODell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.

2012-01-01

The Spectrum-Rontgen-Gamma (SRG) mission is a Russian-German X-ray astrophysical observatory that carries two co-aligned and complementary X-ray telescope systems. The primary instrument is the German-led extended ROentgen Survey with an Imaging Telescope Array (eROSITA), a 7-module X-ray telescope system that covers the energy range from 0.2-12 keV. The complementary instrument is the Russian-led Astronomical Roentgen Telescope -- X-ray Concentrator (ART-XC or ART), a 7-module X-ray telescope system that provides higher energy coverage, up to 30 keV (with limited sensitivity above 12 keV).

Estimating Noise in the Hydrogen Epoch of Reionization Array

NASA Astrophysics Data System (ADS)

Englund Mathieu, Philip; HERA Team

2017-01-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope dedicated to observing large scale structure during and prior to the epoch of reionization. Once completed, HERA will have unprecedented sensitivity to the 21-cm signal from hydrogen reionization. This poster will present time- and frequency-subtraction methods and results from a preliminary analysis of the noise characteristics of the nineteen-element pathfinder array.

Integrated detector array technology for infrared astronomy

NASA Technical Reports Server (NTRS)

Mccreight, c. R.; Goebel, J. H.; Mckelvey, M. E.; Stafford, P. S.; Lee, J. H.

1984-01-01

The status of laboratory and telescope tests of integrated infrared detector array technology for astronomical applications is described. The devices tested represent a number of extrinsic and intrinsic detector materials and various multiplexer designs. Infrared arrays have now been used in successful astronomical applications. These have shown that device sensitivities can be comparable to those of discrete detector systems and excellent astronomical imagery can be produced.

Measurements of the CMB Polarization with POLARBEAR and the Optical Performance of the Simons Array

NASA Astrophysics Data System (ADS)

Takayuki Matsuda, Frederick; POLARBEAR Collaboration

2017-06-01

POLARBEAR is a ground-based polarization sensitive Cosmic Microwave Background (CMB) experiment installed on the 2.5 m aperture Gregorian-Dragone type Huan Tran Telescope located in the Atacama desert in Chile. POLARBEAR is designed to conduct broad surveys at 150 GHz to measure the CMB B-mode polarization signal from inflationary gravitational waves at large angular scales and from gravitational lensing at small angular scales. POLARBEAR started observations in 2012. First season results on gravitational lensing B-mode measurements were published in 2014, and the data analysis of further seasons is in progress. In order to further increase measurement sensitivity, in 2018 the experiment will be upgraded to the Simons Array comprising of three telescopes, each with improved receiver optics using alumina lenses. In order to further expand the observational range, the second and third receiver optics designs were further modified for improved optical performance across the frequencies of 95, 150, 220, and 280 GHz. The diffraction limited field of view was increased especially for the higher frequencies to span a full 4.5 degrees diameter field of view of the telescope. The Simons Array will have a total of 22,764 detectors within this field of view. The Simons Array is projected to put strong constraints on both the measurements of the tensor-to-scalar ratio for inflationary cosmology and the sum of the neutrino masses. I will report on the status of current observations and analysis of the first two observation seasons of POLARBEAR as well as the optics design development of the Simons Array receivers.

Optical Fiber Array Assemblies for Space Flight on the Lunar Reconnaissance Orbiter

NASA Technical Reports Server (NTRS)

Ott, Jelanie; Matuszeski, Adam

2011-01-01

Custom fiber optic bundle array assemblies developed by the Photonics Group at NASA Goddard Space Flight Center were an enabling technology for both the Lunar Orbiter Laser Altimeter (LOLA) and the Laser Ranging (LR) Investigation on the Lunar Reconnaissance Orbiter (LRO) currently in operation. The unique assembly array designs provided considerable decrease in size and weight and met stringent system level requirements. This is the first time optical fiber array bundle assemblies were used in a high performance space flight application. This innovation was achieved using customized Diamond Switzerland AVIM optical connectors. For LOLA, a five fiber array was developed for the receiver telescope to maintain precise alignment for each of the 200/220 micron optical fibers collecting 1,064 nm wavelength light being reflected back from the moon. The array splits to five separate detectors replacing the need for multiple telescopes. An image illustration of the LOLA instrument can be found at the top of the figure. For the laser ranging, a seven-optical-fiber array of 400/440 micron fibers was developed to transmit light from behind the LR receiver telescope located on the end of the high gain antenna system (HGAS). The bundle was routed across two moving gimbals, down the HGAS boom arm, over a deployable mandrel and across the spacecraft to a detector on the LOLA instrument. The routing of the optical fiber bundle and its end locations is identified in the figure. The Laser Ranging array and bundle is currently accepting light at a wavelength of 532 nm sent to the moon from laser stations at Greenbelt MD and other stations around the world to gather precision ranging information from the Earth to the LRO spacecraft. The LR bundle assembly is capable of withstanding temperatures down to -55 C at the connectors, and 20,000 mechanical gimbal cycles at temperatures as cold as -20 C along the length of the seven-fiber bundle (that is packaged into the gimbals). The total bundle assembly is 10 meters long with two interconnections requiring precise clocking of the seven-fiber array pattern.

Wartime vascular injuries in the pediatric population of Iraq and Afghanistan: 2002-2011

DTIC Science & Technology

2014-01-01

United States Army Institute of Surgical Research, San Antonio, TX, USA c CSTARS, St. Louis University, St. Louis, MO, USA d Department of Surgery , San...Antonio Military Medical Center, Fort Sam Houston, TX 78234-6315, USA e Norman M. Rich Department of Surgery , Uniformed Services University of the Health...they are associated with significant morbidity and mortality [4,5]. In contrast to the manage - ment of adult vascular injuries, there is little

Use of Performance Measures to Evaluate, Document Competence and Deterioration of Advanced Surgical Skills Exposure for Trauma (ASSET) Surgical Skills

DTIC Science & Technology

2014-03-01

skills retention. C-STARS . Dr Sharon Henry .. Committee On Trauma of American College of Surgeons Trauma Skills and Beta site Claire Leidy...cadaver sites .. refer to as need to do need a projector and fresh cadavers…11 courses 49 instructors 208 students ..importance of course ..should be...conducted to assess the efficacy of laparoscopic simulation trainers, especially as the technology has rapidly advanced from low-fidelity physical

STS-109 MS Grunsfeld and Linnehan stow old solar array from payload bay

NASA Image and Video Library

2002-03-04

STS109-E-5246 (4 March 2002) --- Astronaut John M. Grunsfeld (foreground), payload commander, is seen at one end of stowed solar panels in the cargo bay of the Space Shuttle Columbia while astronaut Richard M. Linnehan, mission specialist, uses the Remote Manipulator System's robotic arm to move around at the other end. The two, participating in the first of their assigned STS-109 space walks to perform work on the Hubble Space Telescope (HST), went on to replace the giant telescope’s starboard solar array. Their seven-hour space walk ended at 7:38 a.m. (CST) or 13:38 GMT March 4, 2002.

The atmospheric transparency measured with a LIDAR system at the Telescope Array experiment

NASA Astrophysics Data System (ADS)

Tomida, Takayuki; Tsuyuguchi, Yusuke; Arai, Takahito; Benno, Takuya; Chikawa, Michiyuki; Doura, Koji; Fukushima, Masaki; Hiyama, Kazunori; Honda, Ken; Ikeda, Daisuke; Matthews, John N.; Nakamura, Toru; Oku, Daisuke; Sagawa, Hiroyuki; Tokuno, Hisao; Tameda, Yuichiro; Thomson, Gordon B.; Tsunesada, Yoshiki; Udo, Shigeharu; Ukai, Hisashi

2011-10-01

An atmospheric transparency was measured using a LIDAR with a pulsed UV laser (355 nm) at the observation site of Telescope Array in Utah, USA. The measurement at night for two years in 2007-2009 revealed that the extinction coefficient by aerosol at the ground level is 0.033-0.012+0.016km-1 and the vertical aerosol optical depth at 5 km above the ground is 0.035-0.013+0.019. A model of the altitudinal aerosol distribution was built based on these measurements for the analysis of atmospheric attenuation of the fluorescence light generated by ultra high energy cosmic rays.

Energy spectrum of ultra-high energy cosmic rays observed with the Telescope Array using a hybrid technique

NASA Astrophysics Data System (ADS)

Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Miyata, K.; Murano, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Urban, F.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhou, X.; Zollinger, R.; Zundel, Z.

2015-02-01

We measure the spectrum of cosmic rays with energies greater than 1018.2 eV with the fluorescence detectors (FDs) and the surface detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27, 2008 to September 7, 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results.

Optimization of transition edge sensor arrays for cosmic microwave background observations with the south pole telescope

DOE PAGES

Ding, Junjia; Ade, P. A. R.; Anderson, A. J.; ...

2016-12-15

In this study, we describe the optimization of transition-edge-sensor (TES) detector arrays for the thirdgeneration camera for the South PoleTelescope.The camera,which contains ~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

Detector Arrays for the James Webb Space Telescope Near-Infrared Spectrograph

NASA Technical Reports Server (NTRS)

Rauscher, Bernard J.; Alexander, David; Brambora, Clifford K.; Derro, Rebecca; Engler, Chuck; Fox, Ori; Garrison, Matthew B.; Henegar, Greg; Hill, robert J.; Johnson, Thomas;

Space Applications Industrial Laser System (SAILS)

NASA Technical Reports Server (NTRS)

Mccay, T. D.; Bible, J. B.; Mueller, R. E.

1993-01-01

A program is underway to develop a YAG laser based materials processing workstation to fly in the cargo bay of the Space Shuttle. This workstation, called Space Applications Industrial Laser System (SAILS), will be capable of cutting and welding steel, aluminum, and Inconel alloys of the type planned for use in constructing the Space Station Freedom. As well as demonstrating the ability of a YAG laser to perform remote (fiber-optic delivered) repair and fabrication operations in space, fundamental data will be collected on these interactions for comparison with terrestrial data and models. The flight system, scheduled to fly in 1996, will be constructed as three modules using standard Get-Away-Special (GAS) canisters. The first module holds the laser head and cooling system, while the second contains a high peak power electrical supply. The third module houses the materials processing workstation and the command and data acquisition subsystems. The laser head and workstation cansisters are linked by a fiber-optic cable to transmit the laser light. The team assembled to carry out this project includes Lumonics Industrial Products (laser), Tennessee Technological University (structural analysis and fabrication), Auburn University Center for Space Power (electrical engineering), University of Waterloo (low-g laser process consulting), and CSTAR/UTSI (data acquisition, control, software, integration, experiment design). This report describes the SAILS program and highlights recent activities undertaken at CSTAR.

Optical and IR applications in astronomy and astrophysics

NASA Astrophysics Data System (ADS)

McLean, Ian S.

2009-06-01

The set comprising silicon charge-coupled devices, low band-gap infrared arrays and bolometer arrays provide astronomers with position-sensitive photon detectors from the X-ray to the sub-mm. In recent years the most significant advances have occurred in the near-infrared part of the spectrum because not only have the detector formats caught up with those of charge-coupled device (CCDs) but also because the advent of adaptive optics (AO) has meant that the very largest telescopes can achieve their diffraction limit in the near-infrared. Thus infrared cameras, spectrometers and hybrid instruments that measure spatial and spectral information simultaneously are now commanding the greatest attention on telescopes from 6.5 to 10 m in effective aperture. Scientific applications of these new infrared instruments span everything from the search for nearby solar systems to the orbital motions of stars about the massive black hole at the center of the Milky Way, and studies of the first galaxies to form in the high redshift Universe. Background, principles and applications of infrared array detectors to astronomy and astrophysics will be discussed with particular emphasis on work at the W.M. Keck 10-m telescope on Mauna Kea, Hawaii.

Acoustic Transmitters for Underwater Neutrino Telescopes

PubMed Central

Ardid, Miguel; Martínez-Mora, Juan A.; Bou-Cabo, Manuel; Larosa, Giuseppina; Adrián-Martínez, Silvia; Llorens, Carlos D.

2012-01-01

In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters. PMID:22666022

Spectroscopic Capabilities and Possibilities of the Far Infrared and Submillimeter Telescope Mission

NASA Technical Reports Server (NTRS)

Pearson, J. C.

2000-01-01

The Far Infrared and Submillimeter Telescope (FIRST) mission is the fourth European Space Agency corner stone mission. FIRST will be an observatory with a passively cooled (80 Kelvin) 3.5 meter class telescope and three cryogenic instruments covering the 670 to 80 mm spectral region. The mission is slated for a 4.5 year operational lifetime in an L2 orbit. It will share an Arian 5 launch with PLANCK in early 2007. The three payload instruments include the Spectral and Photometric Imaging Receiver (SPIRE), which is a bolometer array with Martin-Puplett FTS for 200-670 microns, the Photoconductor Array Camera and Spectrometer (PACS), which is a photoconductor array with a grating spectrometer for 80-210 microns and the Heterodyne Instrument for FIRST (HIFI), which is a series of seven heterodyne receivers covering 480-1250 GHz and portions of 1410-1910 GHz and 2400-2700 GHz. FIRST will make many detailed spectral surveys of a wide variety of objects previously obscured by the atmosphere and in regions of the spectrum seldom used for astronomical observations, With all of the spectroscopic capability on FIRST a great deal of laboratory spectroscopic support will be needed for accurate interpretation of the spectral data.

Overview of engineering activities at the SMA

NASA Astrophysics Data System (ADS)

Christensen, R. D.; Kubo, D. Y.; Rao, Ramprasad

2008-07-01

The Submillmeter Array (SMA) consists of 8 6-meter telescopes on the summit of Mauna Kea. The array has been designed to operate from the summit of Mauna Kea and from 3 remote facilities: Hilo, Hawaii, Cambridge, Massachusetts and Taipei, Taiwan. The SMA provides high-resolution scientific observations in most of the major atmospheric windows from 180 to 700 GHz. Each telescope can house up to 8 receivers in a single cryostat and can operate with one or two receiver bands simultaneously. The array being a fully operational observatory, the demand for science time is extremely high. As a result specific time frames have been set-aside during both the day and night for engineering activities. This ensures that the proper amount of time can be spent on maintaining existing equipment or upgrading the system to provide high quality scientific output during nighttime observations. This paper describes the methods employed at the SMA to optimize engineering development of the telescopes and systems such that the time available for scientific observations is not compromised. It will also examine some of the tools used to monitor the SMA during engineering and science observations both at the site and remote facilities.

The GCT camera for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Lapington, J. S.; Abchiche, A.; Allan, D.; Amans, J.-P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Bose, R.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Buckley, J.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M. K.; De Franco, A.; De Frondat, F.; Dournaux, J.-L.; Dumas, D.; Ernenwein, J.-P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J.-M.; Jankowsky, D.; Jegouzo, I.; Jogler, T.; Kawashima, T.; Kraus, M.; Laporte, P.; Leach, S.; Lefaucheur, J.; Markoff, S.; Melse, T.; Minaya, I. A.; Mohrmann, L.; Molyneux, P.; Moore, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayede, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Trichard, C.; Varner, G.; Vink, J.; Watson, J. J.; White, R.; Yamane, N.; Zech, A.; Zink, A.; Zorn, J.; CTA Consortium

2017-12-01

The Gamma Cherenkov Telescope (GCT) is one of the designs proposed for the Small Sized Telescope (SST) section of the Cherenkov Telescope Array (CTA). The GCT uses dual-mirror optics, resulting in a compact telescope with good image quality and a large field of view with a smaller, more economical, camera than is achievable with conventional single mirror solutions. The photon counting GCT camera is designed to record the flashes of atmospheric Cherenkov light from gamma and cosmic ray initiated cascades, which last only a few tens of nanoseconds. The GCT optics require that the camera detectors follow a convex surface with a radius of curvature of 1 m and a diameter of 35 cm, which is approximated by tiling the focal plane with 32 modules. The first camera prototype is equipped with multi-anode photomultipliers, each comprising an 8×8 array of 6×6 mm2 pixels to provide the required angular scale, adding up to 2048 pixels in total. Detector signals are shaped, amplified and digitised by electronics based on custom ASICs that provide digitisation at 1 GSample/s. The camera is self-triggering, retaining images where the focal plane light distribution matches predefined spatial and temporal criteria. The electronics are housed in the liquid-cooled, sealed camera enclosure. LED flashers at the corners of the focal plane provide a calibration source via reflection from the secondary mirror. The first GCT camera prototype underwent preliminary laboratory tests last year. In November 2015, the camera was installed on a prototype GCT telescope (SST-GATE) in Paris and was used to successfully record the first Cherenkov light of any CTA prototype, and the first Cherenkov light seen with such a dual-mirror optical system. A second full-camera prototype based on Silicon Photomultipliers is under construction. Up to 35 GCTs are envisaged for CTA.

Is There a Metallicity Ceiling to Form Carbon Stars? - A Novel Technique Reveals a Scarcity of C-Stars in the Inner M31 Disk

NASA Technical Reports Server (NTRS)

Boyer, Martha L.; Girardi, L.; Marigo, P.; Williams, B. F.; Aringer, B.; Nowotny, W.; Rosenfield, P.; Dorman, C. E.; Guhathakurta, P.; Dalcanton, J. J.;

Development and Operation of the Microshutter Array System

NASA Technical Reports Server (NTRS)

Jhabvala, M. D.; Franz, D.; King, T.; Kletetschka, G.; Kutyrev, A. S.; Li, M. J.

2008-01-01

The microshutter array (MSA) is a key component in the James Webb Space Telescope Near Infrared Spectrometer (NIRSpec) instrument. The James Webb Space Telescope is the next generation of a space-borne astronomy platform that is scheduled to be launched in 2013. However, in order to effectively operate the array and meet the severe operational requirements associated with a space flight mission has placed enormous constraints on the microshutter array subsystem. This paper will present an overview and description of the entire microshutter subsystem including the microshutter array, the hybridized array assembly, the integrated CMOS electronics, mechanical mounting module and the test methodology and performance of the fully assembled microshutter subsystem. The NIRSpec is a European Space Agency (ESA) instrument requiring four fully assembled microshutter arrays, or quads, which are independently addressed to allow for the imaging of selected celestial objects onto the two 4 mega pixel IR detectors. Each microshutter array must have no more than approx.8 shutters which are failed in the open mode (depending on how many are failed closed) out of the 62,415 (365x171) total number of shutters per array. The driving science requirement is to be able to select up to 100 objects at a time to be spectrally imaged at the focal plane. The spectrum is dispersed in the direction of the 171 shutters so if there is an unwanted open shutter in that row the light from an object passing through that failed open shutter will corrupt the spectrum from the intended object.

Observational results of a multi-telescope campaign in search of interstellar urea [(NH{sub 2}){sub 2}CO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Remijan, Anthony J.; Snyder, Lewis E.; Kuo, Hsin-Lun

In this paper, we present the results of an observational search for gas phase urea [(NH{sub 2}){sub 2}CO] observed toward the Sgr B2(N-LMH) region. We show data covering urea transitions from ∼100 GHz to 250 GHz from five different observational facilities: the Berkeley-Illinois-Maryland-Association (BIMA) Array, the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the NRAO 12 m telescope, the IRAM 30 m telescope, and the Swedish-ESO Submillimeter Telescope (SEST). The results show that the features ascribed to urea can be reproduced across the entire observed bandwidth and all facilities by best-fit column density, temperature, and source size parameters whichmore » vary by less than a factor of two between observations merely by adjusting for telescope-specific parameters. Interferometric observations show that the emission arising from these transitions is cospatial and compact, consistent with the derived source sizes and emission from a single species. Despite this evidence, the spectral complexity of both (NH{sub 2}){sub 2}CO and of Sgr B2(N) makes the definitive identification of this molecule challenging. We present observational spectra, laboratory data, and models, and discuss our results in the context of a possible molecular detection of urea.« less

Optical and Infrared Spectroscopy of Nova Ophiuchi 2018 No.2

NASA Astrophysics Data System (ADS)

Rudy, R. J.; Mauerhan, J. C.; Russell, R. W.; Subasavage, J. P.; Wiktorowicz, S. J.; Kim, D. L.; Sitko, M. L.

2018-05-01

Over a two week period coming approximately two months after outburst, Nova Ophiuchi 2018, No.2 (CBET 4492) was observed spectroscopically using instruments from three different facilities: 2018 May 6, using the Spex instrument at the Infrared Telescope Facility (0.7-2.5 microns); 2018 May 14, using the Broadband Array Spectrograph System on the 3.6 meter Advanced Electro-Optical Systems telescope (3-13 microns); 2018 May 19, with the VNIRIS spectrograph on the Aerospace Corporation's one meter telescope (0.47-2.5 microns).

-V2 plane on the Hubble Space Telescope

NASA Image and Video Library

2002-03-03

STS109-E-5104 (3 March 2002) --- The Hubble Space Telescope is seen in the cargo bay of the Space Shuttle Columbia. Each present set of solar array panels will be replaced during one of the space walks planned for the coming week. The crew aimed various cameras, including the digital still camera used for this frame, out the shuttle's aft flight deck windows to take a series of survey type photos, the first close-up images of the telescope since December of 1999.

-V2 plane on the Hubble Space Telescope

NASA Image and Video Library

2002-03-03

STS109-E-5102 (3 March 2002) --- The Hubble Space Telescope is seen in the cargo bay of the Space Shuttle Columbia. Each present set of solar array panels will be replaced during one of the space walks planned for the coming week. The crew aimed various cameras, including the digital still camera used for this frame, out the shuttle's aft flight deck windows to take a series of survey type photos, the first close-up images of the telescope since December of 1999.

Rise Time of the Simulated VERITAS 12 m Davies-Cotton Reflector

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, Richard J.

The Very Energetic Radiation Imaging Telescope Array System (VERITAS) will utilise Imaging Atmospheric Cherenkov Telescopes (IACTs) based on a Davies-Cotton design with f-number f/1.0 to detect cosmic gamma-rays. Unlike a parabolic reflector, light from the Davies-Cotton does not arrive isochronously at the camera. Here the effect of the telescope geometry on signal rise-time is examined. An almost square-pulse arrival time profile with a rise time of 1.7 ns is found analytically and confirmed through simulation.

High angular resolution observations of the cool giant V Hya

NASA Astrophysics Data System (ADS)

Pedretti, E.; Monnier, J. D.; Millan Gabet, R.; Traub, W. A.; Tuthill, P.; Danchi, W.; Berger, J.; Schloerb, F. P.; Thureau, N. D.; Carleton, N. P.; Lacasse, M. G.; Schuller, P. A.; Ragland, S.; Brewer, M.

2005-12-01

We present the preliminary interferometric observations of the cool giant star V Hya. V Hya, which is known to have mass-loss and to be surrounded by a dust shell,was observed in three narrow-band filters in the H bandpass at the infrared optical telescope array (IOTA), using the IONIC three-telescope beam combiner. The star was also observed at the Keck telescope using an aperture mask. We discuss the results and try to fit simple models to the observed data.

Multivariable Parametric Cost Model for Ground Optical: Telescope Assembly

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Rowell, Ginger Holmes; Reese, Gayle; Byberg, Alicia

2004-01-01

A parametric cost model for ground-based telescopes is developed using multi-variable statistical analysis of both engineering and performance parameters. While diameter continues to be the dominant cost driver, diffraction limited wavelength is found to be a secondary driver. Other parameters such as radius of curvature were examined. 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 were derived.

South African Student Constructed Indlebe Radio Telescope

NASA Astrophysics Data System (ADS)

McGruder, Charles H.; MacPherson, Stuart; Janse Van Vuuren, Gary Peter

2017-01-01

The Indlebe Radio Telescope (IRT) is a small transit telescope with a 5 m diameter parabolic reflector working at 21 cm. It was completely constructed by South African (SA) students from the Durban University of Technology (DUT), where it is located. First light occurred on 28 July 2008, when the galactic center, Sagittarius A, was detected. As a contribution to the International Year of Astronomy in 2009, staff members in the Department of Electronic Engineering at DUT in 2006 decided to have their students create a fully functional radio telescope by 2009. The specific project aims are to provide a visible project that could generate interest in science and technology in high school students and to provide a real world system for research in radio astronomy in general and an optimization of low noise radio frequency receiver systems in particular. These aims must be understood in terms of the SA’s government interests in radio astronomy. SA is a partner in the Square Kilometer Array (SKA) project, has constructed the Karoo Array Telescope (KAT) and MeerKat, which is the largest and most sensitive radio telescope in the southern hemisphere. SA and its partners in Africa are investing in the construction of the African Very Long Baseline Interferometry Network (AVN), an array of radio telescopes throughout Africa as an extension of the existing global Very Long Baseline Interferometry Network (VLBI). These projects will allow SA to make significant contributions to astronomy and enable astronomy to contribute to the scientific education and development goals of the country. The IRT sees on a daily basis the transit of Sag A. The transit time is influenced by precession, nutation, polar motion, aberration, celestial pole offset, proper motion, length of the terrestrial day and variable ionospheric refraction. Of these eight factors six are either predictable or measureable. To date neither celestial pole offset nor variable ionospheric refraction are predicable. Currently, we are comparing the observed transit times of Sag A with the calculable predications in order to obtain information over these two factors, with a view to better understanding them.

Overview of APEX Capabilities

NASA Astrophysics Data System (ADS)

De Breuck, Carlos

2018-03-01

The APEX telescope has a range instruments that are highly complementary to ALMA. The single pixel heterodyne receivers cover virtually all atmospheric windows from 157 GHz to above 1 THz, augmented by 7-pixel heterodyne arrays covering 280 to 950 GHz, while the bolometer arrays cover the 870, 450 and 350µm bands.

The Detection and Photometric Redshift Determination of Distant Galaxies using SIRTF's Infrared Array Camera

NASA Technical Reports Server (NTRS)

Simpson, C.; Eisenhardt, P.

1998-01-01

We investigate the ability of the Space Infrared Telescope Facility's Infrared Array Camera to detect distant (z3) galaxies and measure their photometric redshifts. Our analysis shows that changing the original long wavelength filter specifications provides significant improvements in performance in this and other areas.

Reliability-centered maintenance for ground-based large optical telescopes and radio antenna arrays

NASA Astrophysics Data System (ADS)

Marchiori, G.; Formentin, F.; Rampini, F.

2014-07-01

In the last years, EIE GROUP has been more and more involved in large optical telescopes and radio antennas array projects. In this frame, the paper describes a fundamental aspect of the Logistic Support Analysis (LSA) process, that is the application of the Reliability-Centered Maintenance (RCM) methodology for the generation of maintenance plans for ground-based large optical telescopes and radio antennas arrays. This helps maintenance engineers to make sure that the telescopes continue to work properly, doing what their users require them to do in their present operating conditions. The main objective of the RCM process is to establish the complete maintenance regime, with the safe minimum required maintenance, carried out without any risk to personnel, telescope and subsystems. At the same time, a correct application of the RCM allows to increase the cost effectiveness, telescope uptime and items availability, and to provide greater understanding of the level of risk that the organization is managing. At the same time, engineers shall make a great effort since the initial phase of the project to obtain a telescope requiring easy maintenance activities and simple replacement of the major assemblies, taking special care on the accesses design and items location, implementation and design of special lifting equipment and handling devices for the heavy items. This maintenance engineering framework is based on seven points, which lead to the main steps of the RCM program. The initial steps of the RCM process consist of: system selection and data collection (MTBF, MTTR, etc.), definition of system boundaries and operating context, telescope description with the use of functional block diagrams, and the running of a FMECA to address the dominant causes of equipment failure and to lay down the Critical Items List. In the second part of the process the RCM logic is applied, which helps to determine the appropriate maintenance tasks for each identified failure mode. Once the logic is completed for all the analyzed items, the resulting Maintenance Program is compiled in order to preserve all the system important functions and to rationalize the tasks periodicities. Lastly, the RCM is kept alive throughout the entire life of the telescope, where the effectiveness of the maintenance is constantly reviewed and adjusted on the basis of the "lesson learned". In addition to the RCM analysis methodology, a second basic concept is applied for the telescope maintenance: to design and install components in such a manner to restore a failure and to perform servicing procedures as close as possible to the telescope, maximizing the replacement of Line Replaceable Units (LRUs) or Shop Replaceable Units (SRUs), rather than repair on-equipment.

LOLA: Lunar Optical Long-baseline Array. 1992-1993 space design

NASA Technical Reports Server (NTRS)

Bronte, Daniel; Chaney, Joanne; Curran, Christine; Ferguson, Keith; Flint, Eric; Giunta, Tony; Knill, Duane; Levesque, Daniel; Lyon, Donald; Murphy, Sean

1993-01-01

In the fall of 1992, the design and analysis of a lunar-based optical interferometer telescope array was initiated by a group of students in the Department of Aerospace Engineering at Virginia Tech. This project was undertaken at the suggestion of the Space Exploration Initiative Office at the NASA Langley Research Center. The original array design requirements, listed below, centered on the primary objective of resolving earth-type planets about stars out to a distance of ten parsecs: spectrum coverage spanning wavelengths from five nm to five mm, with a primary operating mode in the visible spectrum; a total collecting area providing a signal-to-noise ratio (SNR) of no less than 10.0 for a median wavelength of 500 nm; the individual array elements must be identical and have a maximum optical diameter of 2.0 m; and lunar site selection is limited to ten degrees north and south of the lunar equator on the lunar far side while not closer than 15 degrees to either near-side limb. Following construction by astronaut crews, array operation will be conducted from earth and astronomical observations will not be conducted during the lunar day. The entire system is designed for minimum achievable mass. The majority of the original design requirements for the telescope array were met.

Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST/AFTA

NASA Technical Reports Server (NTRS)

Gong, Qian; McElwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Hilton, George; Perrin, Marshall; Sayson, Llop; Domingo, Jorge;

Multi-epoch Measurements of the Galactic Center 6667 MHz) and the Blazar 0716+714 (1 & 3 MHz) taken from the Allen Telescope Array at Hat Creek Radio Observatory in 2013

NASA Astrophysics Data System (ADS)

Castellanos, Aaron; Harp, G.

2014-01-01

The Allen Telescope Array (ATA) is a 42 radio dish array located in Hat Creek, CA and is used to search for traces of Extraterrestrial Intelligence (SETI) and to study the interstellar medium. The ATA has taken multi-epoch measurements of the Galactic Center 6667 MHz) and the intraday variable Blazar 0716+714 (1 & 3MHz) and are imaged on 10 second timescales to search for intensity fluctuations on timescales 10s and beyond. We utilize software developed and focused on antenna system temperatures to minimize Radio Frequency Interference (RFI) in order to enhance calibration and signal variability. We will discuss potential radio bursts from the Galactic Center, possibly originating from the descent of the gas cloud G2 into the Galactic Center.

Five Years of SETI with the Allen Telescope Array: Lessons Learned

NASA Astrophysics Data System (ADS)

Harp, Gerald

2016-01-01

We discuss recent observations at the Allen Telescope Array (ATA) supporting a wide ranging Search for Extraterrestrial Intelligence (SETI). The ATA supports observations over the frequency range 1-10 GHz with three simultaneous phased array beams used in an anticoincidence detector for false positive rejection. Here we summarize observational results over the years 2011-2015 covering multiple campaigns of exoplanet stars, the galactic plane, infrared excess targets, etc. Approximately 2 x 108 signals were identified and classified over more than 5000 hours of observation. From these results we consider various approaches to the rapid identification of human generated interference in the process of the search for a signal with origins outside the radius of the Moon's orbit. We conclude that the multi-beam technique is superb tool for answering the very difficult question of the direction of origin of signals. Data-based simulations of future instruments with more than 3 beams are compared.

NRAO Teams With NASA Gamma-Ray Satellite

NASA Astrophysics Data System (ADS)

2007-06-01

The National Radio Astronomy Observatory (NRAO) is teaming with NASA's upcoming Gamma-ray Large Area Space Telescope (GLAST) to allow astronomers to use both the orbiting facility and ground-based radio telescopes to maximize their scientific payoff. Under the new, streamlined process, astronomers can compete for coordinated observing time and support from both GLAST and NRAO's radio telescopes. GLAST satellite Artist's rendering of the GLAST spacecraft in orbit above the Earth. CREDIT: General Dynamics C4 Systems Click on Image for Larger File Images of NRAO Telescopes Robert C. Byrd Green Bank Telescope Very Long Baseline Array Very Large Array Atacama Large Millimeter/submillimeter Array GLAST is scheduled for launch no earlier than December 14. It will perform a survey of the entire sky at gamma-ray wavelengths every 3 hours using its primary instrument, the Large Area Telescope (LAT). NRAO operates the Very Large Array (VLA) in New Mexico, the continent-wide Very Long Baseline Array (VLBA), and the Robert C. Byrd Green Bank Telescope (GBT) in West Virginia. The NRAO is a research facility of the National Science Foundation (NSF). "Coordinated gamma-ray and radio observations of celestial objects will greatly enhance the ability to fully understand those objects. Astronomy today requires such multiwavelength studies, and this agreement paves the way for exciting, cutting-edge research," said Fred K.Y. Lo, NRAO Director. GLAST will be vastly more capable than previous gamma-ray satellites, and will carry an instrument, the GLAST Burst Monitor, specifically designed to detect gamma-ray bursts. GLAST observers will study objects such as active galaxies, pulsars, and supernova remnants, which are also readily studied with radio telescopes. By working together, NASA's GLAST mission and NSF's NRAO facilities can study flares from blazars over the widest possible range of energies, which is crucial to understanding how black holes, notorious for drawing matter in, can accelerate jets of material to nearly light speed. "The gamma-ray and radio observations will show scientists different aspects of many still-mysterious objects and processes. By providing a simple procedure for astronomers to win observing time on radio telescopes to follow up on our new gamma-ray discoveries, we're ensuring that we get the maximum scientific return from both," said GLAST project scientist Steve Ritz of NASA's Goddard Space Flight Center in Greenbelt, Md. "The importance of this coordinated approach has been highlighted by a recent two-day workshop at Goddard, in which we discussed the scientific benefits and coordination of radio Very Long Baseline Interferometry observations made in conjunction with GLAST." NRAO's radio telescopes have been used for many years as part of multiwavelength observing programs in conjunction with both ground-based and space-based observatories. Usually, however, astronomers had to submit separate observing proposals to two or more review committees, with no guarantee that they would win observing time on all desired telescopes. For its part, NASA spacecraft such as the Compton Gamma-Ray Observatory and the Chandra X-ray Observatory have opened wide new windows on the high-energy universe. Astronomers, including those on a recent NSF Senior Review panel, have urged reductions in administrative barriers to gaining observing time at multiple wavelengths. "This NRAO-GLAST agreement eases the process of winning observing time on NRAO telescopes to complement the GLAST all-sky gamma-ray survey. In particular, the continent-wide VLBA is the only existing radio telescope that can image and monitor the sites of extreme gamma-ray flares in distant galaxies," said Jim Ulvestad, NRAO's Director for VLA-VLBA Operations. "We expect to see arrangements like this become much more common in the future, to the benefit of the science." The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. NASA's GLAST mission is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

Observing with Sibling and Twin Telescopes

NASA Astrophysics Data System (ADS)

Plank, Lucia; Lovell, Jim; McCallum, Jamie; Mayer, David

2016-12-01

With the transition to VGOS, co-located radio telescopes will be common at many sites. This can be as a sibling telescope when a VGOS antenna is built next to a legacy one, or as the concept of a twin telescope with two identical VGOS antennas. The co-location of two antennas offers new possibilities in both operation and analysis. The immediate question for observing with sibling/twin telescopes is the applied observing strategy and its realization in the scheduling software. In this contribution we report about our efforts implementing new scheduling modes for sibling and twin telescopes in the Vienna VLBI Software. For the example of the sibling telescope in Hobart, several types of sessions will be discussed: an improved tag-along mode for the 26-m antenna (Ho), a proper implementation of the twin-mode using the antenna with the shorter slewing time, and an astrometric support mode enabling the observation of weak sources with the AuScope array.

Observations of Interplanetary Scintillation (IPS) Using the Mexican Array Radio Telescope (MEXART)

NASA Astrophysics Data System (ADS)

Mejia-Ambriz, J. C.; Villanueva-Hernandez, P.; Gonzalez-Esparza, J. A.; Aguilar-Rodriguez, E.; Jeyakumar, S.

2010-08-01

The Mexican Array Radio Telescope (MEXART) consists of a 64×64 (4096) full-wavelength dipole antenna array, operating at 140 MHz, with a bandwidth of 2 MHz, occupying about 9660 square meters (69 m × 140 m) ( http://www.mexart.unam.mx ). This is a dedicated radio array for Interplanetary Scintillation (IPS) observations located at latitude 19°48'N, longitude 101°41'W. We characterize the performance of the system. We report the first IPS observations with the instrument, employing a Butler Matrix (BM) of 16×16 ports, fed by 16 east - west lines of 64 dipoles (1/4 of the total array). The BM displays a radiation pattern of 16 beams at different declinations (from -48, to +88 degrees). We present a list of 19 strong IPS radio sources (having at least 3 σ in power gain) detected by the instrument. We report the power spectral analysis procedure of the intensity fluctuations. The operation of MEXART will allow us a better coverage of solar wind disturbances, complementing the data provided by the other, previously built, instruments.

Space Shuttle Projects

NASA Image and Video Library

2002-03-07

STS-109 Astronaut Michael J. Massimino, mission specialist, perched on the Shuttle's robotic arm is working at the stowage area for the Hubble Space Telescope's port side solar array. Working in tandem with James. H. Newman, Massimino removed the old port solar array and stored it in Columbia's payload bay for return to Earth. The two went on to install a third generation solar array and its associated electrical components. Two crew mates had accomplished the same feat with the starboard array on the previous day. In addition to the replacement of the solar arrays, the STS-109 crew also installed the experimental cooling system for the Hubble's Near-Infrared Camera (NICMOS), replaced the power control unit (PCU), and replaced the Faint Object Camera (FOC) with a new advanced camera for Surveys (ACS). The 108th flight overall in NASA's Space Shuttle Program, the Space Shuttle Columbia STS-109 mission lifted off March 1, 2002 for 10 days, 22 hours, and 11 minutes. Five space walks were conducted to complete the HST upgrades. The Marshall Space Flight Center in Huntsville, Alabama had the responsibility for the design, development, and construction of the HST, which is the most powerful and sophisticated telescope ever built.

Discovery of KPS-1b, a Transiting Hot-Jupiter, with an Amateur Telescope Setup (Abstract)

NASA Astrophysics Data System (ADS)

Benni, P.; Burdanov, A.; Krushinsky, V.; Sokov, E.

2018-06-01

(Abstract only) Using readily available amateur equipment, a wide-field telescope (Celestron RASA, 279 mm f/2.2) coupled with a SBIG ST-8300M camera was set up at a private residence in a fairly light polluted suburban town thirty miles outside of Boston, Massachusetts. This telescope participated in the Kourovka Planet Search (KPS) prototype survey, along with a MASTER-II Ural wide field telescope near Yekaterinburg, Russia. One goal was to determine if higher resolution imaging ( 2 arcsec/pixel) with much lower sky coverage can practically detect exoplanet transits compared to the successful very wide-field exoplanet surveys (KELT, XO, WASP, HATnet, TrES, Qatar, etc.) which used an array of small aperture telescopes coupled to CCDs.

Millimeter and submillimeter observations from the Atacama plateau and high altitude balloons

NASA Astrophysics Data System (ADS)

Devlin, Mark

2002-05-01

A new generation of ground-based and sub-orbital platforms will be operational in the next few years. These telescopes will operate from high sites in Chile and Antarctica, and airborne platforms where the atmosphere is transparent enough to allow sensitive measurements in the millimeter and submillimeter bands. The telescopes will employ state-of-the-art instrumentation including large format bolometer arrays and spectrometers. I will discuss the results of our observations in the Atacama region of Chile (MAT/TOCO), our future observations on the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) now under construction, and our proposed Atacama Cosmology Telescope (ACT). .

The Primordial Inflation Polarization Explorer (PIPER)

NASA Technical Reports Server (NTRS)

Chuss, David T.

2010-01-01

The Primordial Inflation Polarization Explorer (PIPER) is a ba1loon-borne instrument designed to search for the faint signature of inflation in the polarized component of the cosmic microwave background (CMB). PIPER will measure the CMB polarization at 4 frequencies (l per flight) using a pair of cryogenic telescopes, one for measuring each of Stokes Q and U in the instrument frame. Each telescope receives both linear orthogonal polarizations in two 32 by 40 element planar arrays that utilize Transition-Edge Sensors (TES). The first element in each telescope is a variable-delay polarization modulator (VPM) that fully modulates the Stokes parameter to which the telescope is sensitive.

Thermal Performance of the Hubble Space Telescope (HST) Solar Array-3 During the Disturbance Verification Test (DVT)

NASA Technical Reports Server (NTRS)

Nguyen, Daniel H.; Skladany, Lynn M.; Prats, Benito D.; Griffin, Thomas J. (Technical Monitor)

2001-01-01

The Hubble Space Telescope (HST) is one of NASA's most productive astronomical observatories. Launched in 1990, the HST continues to gather scientific data to help scientists around the world discover amazing wonders of the universe. To maintain HST in the fore front of scientific discoveries, NASA has routinely conducted servicing missions to refurbish older equipment as well as to replace existing scientific instruments with better, more powerful instruments. In early 2002, NASA will conduct its fourth servicing mission to the HST. This servicing mission is named Servicing Mission 3B (SM3B). During SM3B, one of the major refurbishment efforts will be to install new rigid-panel solar arrays as a replacement for the existing flexible-foil solar arrays. This is necessary in order to increase electrical power availability for the new scientific instruments. Prior to installing the new solar arrays on HST, the HST project must be certain that the new solar arrays will not cause any performance degradations to the observatory. One of the major concerns is any disturbance that can cause pointing Loss of Lock (LOL) for the telescope. While in orbit, the solar-array temperature transitions quickly from sun to shadow. The resulting thermal expansion and contraction can cause a "mechanical disturbance" which may result in LOL. To better characterize this behavior, a test was conducted at the European Space Research and Technology Centre (ESTEC) in the Large Space Simulator (LSS) thermal-vacuum chamber. In this test, the Sun simulator was used to simulate on-orbit effects on the solar arrays. This paper summarizes the thermal performance of the Solar Array-3 (SA3) during the Disturbance Verification Test (DVT). The test was conducted between 26 October 2000 and 30 October 2000. Included in this paper are: (1) brief description of the SA3's components and its thermal design; (2) a summary of the on-orbit temperature predictions; (3) pretest thermal preparations; (4) a description of the chamber and thermal monitoring sensors; and (6) presentation of test thermal data results versus flight predictions.

Alternative Optimizations of X-ray TES Arrays: Soft X-rays, High Count Rates, and Mixed-Pixel Arrays

NASA Technical Reports Server (NTRS)

Kilbourne, C. A.; Bandler, S. R.; Brown, A.-D.; Chervenak, J. A.; Figueroa-Feliciano, E.; Finkbeiner, F. M.; Iyomoto, N.; Kelley, R. L.; Porter, F. S.; Smith, S. J.

2007-01-01

We are developing arrays of superconducting transition-edge sensors (TES) for imaging spectroscopy telescopes such as the XMS on Constellation-X. While our primary focus has been on arrays that meet the XMS requirements (of which, foremost, is an energy resolution of 2.5 eV at 6 keV and a bandpass from approx. 0.3 keV to 12 keV), we have also investigated other optimizations that might be used to extend the XMS capabilities. In one of these optimizations, improved resolution below 1 keV is achieved by reducing the heat capacity. Such pixels can be based on our XMS-style TES's with the separate absorbers omitted. These pixels can added to an array with broadband response either as a separate array or interspersed, depending on other factors that include telescope design and science requirements. In one version of this approach, we have designed and fabricated a composite array of low-energy and broad-band pixels to provide high spectral resolving power over a broader energy bandpass than could be obtained with a single TES design. The array consists of alternating pixels with and without overhanging absorbers. To explore optimizations for higher count rates, we are also optimizing the design and operating temperature of pixels that are coupled to a solid substrate. We will present the performance of these variations and discuss other optimizations that could be used to enhance the XMS or enable other astrophysics experiments.

Active telescope systems; Proceedings of the Meeting, Orlando, FL, Mar. 28-31, 1989

NASA Astrophysics Data System (ADS)

Roddier, Francois J.

1989-09-01

The present conference discusses topics in the fundamental limitations of adaptive optics in astronomical telescopy, integrated telescope systems designs, novel components for adaptive telescopes, active interferometry, flexible-mirror and segmented-mirror telescopes, and various aspects of the NASA Precision Segmented Reflectors Program. Attention is given to near-ground atmospheric turbulence effects, a near-IR astronomical adaptive optics system, a simplified wavefront sensor for adaptive mirror control, excimer laser guide star techniques for adaptive astronomical imaging, active systems in long-baseline interferometry, mirror figure control primitives for a 10-m primary mirror, and closed-loop active optics for large flexible mirrors subject to wind buffet deformations. Also discussed are active pupil geometry control for a phased-array telescope, extremely lightweight space telescope mirrors, segmented-mirror manufacturing tolerances, and composite deformable mirror design.

Thermally Induced Vibrations of the Hubble Space Telescope's Solar Array 3 in a Test Simulated Space Environment

NASA Technical Reports Server (NTRS)

Early, Derrick A.; Haile, William B.; Turczyn, Mark T.; Griffin, Thomas J. (Technical Monitor)

2001-01-01

NASA Goddard Space Flight Center and the European Space Agency (ESA) conducted a disturbance verification test on a flight Solar Array 3 (SA3) for the Hubble Space Telescope using the ESA Large Space Simulator (LSS) in Noordwijk, the Netherlands. The LSS cyclically illuminated the SA3 to simulate orbital temperature changes in a vacuum environment. Data acquisition systems measured signals from force transducers and accelerometers resulting from thermally induced vibrations of the SAI The LSS with its seismic mass boundary provided an excellent background environment for this test. This paper discusses the analysis performed on the measured transient SA3 responses and provides a summary of the results.

EVA 2 - MS Massimino waves to crewmates

NASA Image and Video Library

2002-03-05

STS109-E-5606 (5 March 2002) --- Astronaut Michael J. Massimino, mission specialist, waves to crewmates on the other side of the aft flight deck windows on Columbia, while equipped with his extravehicular mobility units (EMU) space suit and standing on the end of the Remote Manipulator System (RMS) arm in the shuttle's cargo bay. This day's space walk went on to see astronauts James H. Newman and Massimino replace the port solar array on the Hubble Space Telescope (HST), partially visible in the background. On the previous day astronauts John M. Grunsfeld and Richard M. Linnehan replaced the starboard solar array on the giant telescope. The image was recorded with a digital still camera.

Study of Microwave Radiation from the Electron Beam at the Telescope Array Site

NASA Astrophysics Data System (ADS)

Ikeda, Daisuke; Gaïor, Romain; Mase, Keiichi; Shin, Bokkyun; De Vries, Krijn; Yamamoto, Tokonatsu; Ishihara, Aya; Kuwabara, Takao; Yoshida, Shigeru; Shibata, Tatsunobu; Ohta, Izumi S.; Ogio, Shoichi; Fukushima, Masaki; Sagawa, Hiroyuki; Matthews, John N.; Thomson, Gordon B.; Hanson, Kael; Meures, Thomas; Murchadha, Aongus Ó.

The Telescope Array (TA) experiment installed the electron accelerator in order to calibrate the fluorescence detector by shooting 40 MeV electrons into the atmosphere. This accelerator also works to investigate the radio detection techniques used for the cosmic ray observations. Using this accelerator, four experimental groups have studied individual radio detection methods at different frequency bands ranging from 50 MHz to 12 GHz. All of these experiments have observed the microwave radiation from the electron beam itself. We have studied the radiation by combining all the measured results and constructed a model of this phenomena. Results of four experiments and model expectation are in good agreement within the systematic uncertainty.

Feedhorn-Coupled Transition-Edge Superconducting Bolometer Arrays for Cosmic Microwave Background Polarimetry

NASA Technical Reports Server (NTRS)

Hubmayr, J.; Austermann, J.; Beall, J.; Becker, D.; Cho, H.-M.; Datta, R.; Duff, S. M.; Grace, E.; Halverson, N.; Henderson, S. W.;

Artificial intelligence for the CTA Observatory scheduler

NASA Astrophysics Data System (ADS)

Colomé, Josep; Colomer, Pau; Campreciós, Jordi; Coiffard, Thierry; de Oña, Emma; Pedaletti, Giovanna; Torres, Diego F.; Garcia-Piquer, Alvaro

2014-08-01

The Cherenkov Telescope Array (CTA) project will be the next generation ground-based very high energy gamma-ray instrument. The success of the precursor projects (i.e., HESS, MAGIC, VERITAS) motivated the construction of this large infrastructure that is included in the roadmap of the ESFRI projects since 2008. CTA is planned to start the construction phase in 2015 and will consist of two arrays of Cherenkov telescopes operated as a proposal-driven open observatory. Two sites are foreseen at the southern and northern hemispheres. The CTA observatory will handle several observation modes and will have to operate tens of telescopes with a highly efficient and reliable control. Thus, the CTA planning tool is a key element in the control layer for the optimization of the observatory time. The main purpose of the scheduler for CTA is the allocation of multiple tasks to one single array or to multiple sub-arrays of telescopes, while maximizing the scientific return of the facility and minimizing the operational costs. The scheduler considers long- and short-term varying conditions to optimize the prioritization of tasks. A short-term scheduler provides the system with the capability to adapt, in almost real-time, the selected task to the varying execution constraints (i.e., Targets of Opportunity, health or status of the system components, environment conditions). The scheduling procedure ensures that long-term planning decisions are correctly transferred to the short-term prioritization process for a suitable selection of the next task to execute on the array. In this contribution we present the constraints to CTA task scheduling that helped classifying it as a Flexible Job-Shop Problem case and finding its optimal solution based on Artificial Intelligence techniques. We describe the scheduler prototype that uses a Guarded Discrete Stochastic Neural Network (GDSN), for an easy representation of the possible long- and short-term planning solutions, and Constraint Propagation techniques. A simulation platform, an analysis tool and different test case scenarios for CTA were developed to test the performance of the scheduler and are also described.

Large array of 2048 tilting micromirrors for astronomical spectroscopy: optical and cryogenic characterization

NASA Astrophysics Data System (ADS)

Zamkotsian, Frédéric; Canonica, Michael; Lanzoni, Patrick; Noell, Wilfried; Lani, Sebastien

2014-03-01

Multi-object spectroscopy (MOS) is a powerful tool for space and ground-based telescopes for the study of the formation and evolution of galaxies. This technique requires a programmable slit mask for astronomical object selection. We are engaged in a European development of micromirror arrays (MMA) for generating reflective slit masks in future MOS, called MIRA. MMA with 100 × 200 μm2 single-crystal silicon micromirrors were successfully designed, fabricated and tested. Arrays are composed of 2048 micromirrors (32 x 64) with a peak-to-valley deformation less than 10 nm, a tilt angle of 24° for an actuation voltage of 130 V. The micromirrors were actuated successfully before, during and after cryogenic cooling, down to 162K. The micromirror surface deformation was measured at cryo and is below 30 nm peak-to-valley. These performances demonstrate the ability of such MOEMS device to work as objects selector in future generation of MOS instruments both in ground-based and space telescopes. In order to fill large focal planes (mosaicing of several chips), we are currently developing large micromirror arrays integrated with their electronics.

Characterization of AlMn TES Impedance, Noise, and Optical Efficiency in the First 150 mm Multichroic Array for Advanced ACTPol

NASA Technical Reports Server (NTRS)

Crowley, Kevin T.; Choi, Steve K.; Kuan, Jeffrey; Austermann, Jason E.; Beall, James A.; Datta, Rahul; Duff, Shannon M.; Gallardo, Patricia A.; Hasselfield, Matthew; Henderson, Shawn W.;

Image Reconstruction from Sparse Irregular Intensity Interferometry Measurements of Fourier Magnitude

DTIC Science & Technology

2013-09-01

of baselines than would a pattern with equal spacing . Nevertheless, many of the telescope pairs have equivalent baselines resulting in...magnitude to a spatial domain representation of the object, sparse and irregular spacing of the measurements in the Fourier plane, and low SNR...any particular geometry of the telescope array configuration. Its inputs are a list of measurements, each

VIRUS: first deployment of the massively replicated fiber integral field spectrograph for the upgraded Hobby-Eberly Telescope

NASA Astrophysics Data System (ADS)

Hill, Gary J.; Tuttle, Sarah E.; Vattiat, Brian L.; Lee, Hanshin; Drory, Niv; Kelz, Andreas; Ramsey, Jason; Peterson, Trent W.; DePoy, D. L.; Marshall, J. L.; Gebhardt, Karl; Chonis, Taylor; Dalton, Gavin; Farrow, Daniel; Good, John M.; Haynes, Dionne M.; Indahl, Briana L.; Jahn, Thomas; Kriel, Hermanus; Montesano, Francesco; Nicklas, Harald; Noyola, Eva; Prochaska, Travis; Allen, Richard D.; Bender, Ralf; Blanc, Guillermo; Fabricius, Maximilian H.; Finkelstein, Steve; Landriau, Martin; MacQueen, Phillip J.; Roth, M. M.; Savage, R. D.; Snigula, Jan M.; Anwad, Heiko

2016-08-01

The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of 156 identical spectrographs (arrayed as 78 pairs) fed by 35,000 fibers, each 1.5 arcsec diameter, at the focus of the upgraded 10 m Hobby-Eberly Telescope (HET). VIRUS has a fixed bandpass of 350-550 nm and resolving power R 700. VIRUS is the first example of industrial-scale replication applied to optical astronomy and is capable of surveying large areas of sky, spectrally. The VIRUS concept offers significant savings of engineering effort, cost, and schedule when compared to traditional instruments. The main motivator for VIRUS is to map the evolution of dark energy for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX‡), using 0.8M Lyman-alpha emitting galaxies as tracers. The VIRUS array is undergoing staged deployment during 2016 and 2017. It will provide a powerful new facility instrument for the HET, well suited to the survey niche of the telescope, and will open up large spectroscopic surveys of the emission line universe for the first time. We will review the production, lessons learned in reaching volume production, characterization, and first deployment of this massive instrument.

Inauguration and first light of the GCT-M prototype for the Cherenkov telescope array

NASA Astrophysics Data System (ADS)

Watson, J. J.; De Franco, A.; Abchiche, A.; Allan, D.; Amans, J.-P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M. K.; De Frondat, F.; Dournaux, J.-L.; Dumas, D.; Ernenwein, J.-P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J.-M.; Jegouzo, I.; Jogler, T.; Kraus, M.; Lapington, J. S.; Laporte, P.; Lefaucheur, J.; Markoff, S.; Melse, T.; Mohrmann, L.; Molyneux, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayède, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Trichard, C.; Vink, J.; White, R.; Yamane, N.; Zech, A.; Zink, A.; Zorn, J.; CTA Consortium

2017-01-01

The Gamma-ray Cherenkov Telescope (GCT) is a candidate for the Small Size Telescopes (SSTs) of the Cherenkov Telescope Array (CTA). Its purpose is to extend the sensitivity of CTA to gamma-ray energies reaching 300 TeV. Its dual-mirror optical design and curved focal plane enables the use of a compact camera of 0.4 m diameter, while achieving a field of view of above 8 degrees. Through the use of the digitising TARGET ASICs, the Cherenkov flash is sampled once per nanosecond contin-uously and then digitised when triggering conditions are met within the analogue outputs of the photosensors. Entire waveforms (typically covering 96 ns) for all 2048 pixels are then stored for analysis, allowing for a broad spectrum of investigations to be performed on the data. Two prototypes of the GCT camera are under development, with differing photosensors: Multi-Anode Photomultipliers (MAPMs) and Silicon Photomultipliers (SiPMs). During November 2015, the GCT MAPM (GCT-M) prototype camera was integrated onto the GCT structure at the Observatoire de Paris-Meudon, where it observed the first Cherenkov light detected by a prototype instrument for CTA.

Optical long baseline intensity interferometry: prospects for stellar physics

NASA Astrophysics Data System (ADS)

Rivet, Jean-Pierre; Vakili, Farrokh; Lai, Olivier; Vernet, David; Fouché, Mathilde; Guerin, William; Labeyrie, Guillaume; Kaiser, Robin

2018-06-01

More than sixty years after the first intensity correlation experiments by Hanbury Brown and Twiss, there is renewed interest for intensity interferometry techniques for high angular resolution studies of celestial sources. We report on a successful attempt to measure the bunching peak in the intensity correlation function for bright stellar sources with 1 meter telescopes (I2C project). We propose further improvements of our preliminary experiments of spatial interferometry between two 1 m telescopes, and discuss the possibility to export our method to existing large arrays of telescopes.

UKIRT observer's manual

NASA Astrophysics Data System (ADS)

Davies, J. K.

1991-04-01

The United Kingdom 3.8 m Infrared Telescope (UKIRT) located at the summit of Mauna Kea on the big island of Hawaii is described. Summit sky conditions are photometric more than half the time and spectroscopic more than three quarters of the time. Photometry through all atmospheric windows in the 1 to 30 micrometer range and spectroscopy in the 1 to 5 micrometer range are possible. The telescope is equipped with a 1 to 5 micrometer infrared camera housing a 58 by 62 element detector array. Other individual instruments and aspects of operation at the telescope are described.

Wide field of view telescope

DOEpatents

Ackermann, Mark R [Albuquerque, NM; McGraw, John T [Placitas, NM; Zimmer, Peter C [Albuquerque, NM

2008-01-15

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

Spectrum measurement with the Telescope Array Low Energy Extension (TALE) fluorescence detector

NASA Astrophysics Data System (ADS)

Zundel, Zachary James

The Telescope Array (TA) experiment is the largest Ultra High Energy cosmic ray observatory in the northern hemisphere and is designed to be sensitive to cosmic ray air showers above 1018eV. Despite the substantial measurements made by TA and AUGER (the largest cosmic ray observatory in the southern hemisphere), there remains uncertainty about whether the highest energy cosmic rays are galactic or extragalactic in origin. Locating features in the cosmic ray energy spectrum below 1018eV that indicate a transition from galactic to extragalactic sources would clarify the interpretation of measurements made at the highest energies. The Telescope Array Low Energy Extension (TALE) is designed to extend the energy threshold of the TA observatory down to 1016.5eV in order to make such measurements. This dissertation details the construction, calibration, and operation of the TALE flu- orescence detector. A measurement of the flux of cosmic rays in the energy range of 1016.5 -- 1018.5eV is made using the monocular data set taken between September 2013 and January 2014. The TALE fluorescence detector observes evidence for a softening of the cosmic spectrum at 1017.25+/-0.5eV. The evidence of a change in the spectrum motivates continued study of 1016.5 -- 1018.5eV cosmic rays.

Telescope array for extrasolar planet detection from the far side of the Moon.

PubMed

Galan, Maximilian; Strojnik, Marija; Garcia-Torales, Guillermo; Kirk, Maureen S

2016-12-01

We propose that an array of 4×4 small-diameter telescopes, possibly 1 m in radius, be placed on the far side of the Moon for continuous monitoring of nearby stars for the existence of a planetary companion, similar to the Earth, and feasible for human colonization. The advantages of this location include long intervals of darkness, availability of a rigid platform in the form of a moon body, and most importantly, the absence of the atmosphere that allows the complete transmission of radiation in the spectral range from UV to millimeter waves. The task is facilitated in that the telescopes would act as light "buckets" to collect photons during long integration periods. All other technology has already been demonstrated, as humans in person delivered optical elements to the Moon's surface during the Apollo era. The disadvantages are primarily operational, in terms of requiring the establishment of a human habitat on the Moon. Likewise, all aspects of constructing a large 75 m by 75 m mirror array on the Moon's surface will be challenging. Simultaneously, the decreased gravity requires less effort and less energy to perform the construction tasks. The absence of atmosphere permits the search to extend from less than 10 to 300 μm to find Earth-like or even much colder planets.

High Precision Photometry of Bright Transiting Exoplanet Hosts

NASA Astrophysics Data System (ADS)

Wilson, Maurice; Eastman, Jason; Johnson, John A.

2016-01-01

Within the past two decades, the successful search for exoplanets and the characterization of their physical properties have shown the immense progress that has been made towards finding planets with characteristics similar to Earth. For most exoplanets with a radius about the size of Earth, evaluating their physical properties, such as the mass, radius and equilibrium temperature, cannot be determined with satisfactory precision. The MINiature Exoplanet Radial Velocity Array (MINERVA) was recently built to obtain spectroscopic and photometric measurements to find, confirm, and characterize Earth-like exoplanets. MINERVA's spectroscopic survey targets the brightest, nearby stars which are well-suited to the array's capabilities, while its primary photometric goal is to search for transits around these bright targets. Typically, it is difficult to find satisfactory comparison stars within a telescope's field of view when the primary target is very bright. This issue is resolved by using one of MINERVA's telescopes to observe the primary bright star while the other telescopes observe a distinct field of view that contains satisfactory bright comparison stars. We describe the code used to identify nearby comparison stars, schedule the four telescopes, produce differential photometry from multiple telescopes, and show the first results from this effort.This work has been funded by the Ronald E. McNair Post-Baccalaureate Achievement Program, the ERAU Honors Program, the ERAU Undergraduate Research Spark Fund, and the Banneker Institute at the Harvard-Smithsonian Center for Astrophysics.

Development and test of photon-counting microchannel plate detector arrays for use on space telescopes

NASA Technical Reports Server (NTRS)

Timothy, J. G.

1976-01-01

The full sensitivity, dynamic range, and photometric stability of microchannel array plates(MCP) are incorporated into a photon-counting detection system for space operations. Components of the system include feedback-free MCP's for high gain and saturated output pulse-height distribution with a stable response; multi-anode readout arrays mounted in proximity focus with the output face of the MCP; and multi-layer ceramic headers to provide electrical interface between the anode array in a sealed detector tube and the associated electronics.

Sensitivity of the Cherenkov Telescope Array to the detection of a dark matter signal in comparison to direct detection and collider experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balazs, Csaba; Conrad, Jan; Farmer, Ben

Imaging atmospheric Cherenkov telescopes (IACTs) that are sensitive to potential γ-ray signals from dark matter (DM) annihilation above ~50 GeV will soon be superseded by the Cherenkov Telescope Array (CTA). CTA will have a point source sensitivity an order of magnitude better than currently operating IACTs and will cover a broad energy range between 20 GeV and 300 TeV. Using effective field theory and simplified models to calculate γ-ray spectra resulting from DM annihilation, we compare the prospects to constrain such models with CTA observations of the Galactic center with current and near-future measurements at the Large Hadron Collider (LHC)more » and direct detection experiments. Here, for DM annihilations via vector or pseudoscalar couplings, CTA observations will be able to probe DM models out of reach of the LHC, and, if DM is coupled to standard fermions by a pseudoscalar particle, beyond the limits of current direct detection experiments.« less

The Receiver System for the Ooty Wide Field Array

NASA Astrophysics Data System (ADS)

Subrahmanya, C. R.; Prasad, P.; Girish, B. S.; Somashekar, R.; Manoharan, P. K.; Mittal, A. K.

2017-03-01

The legacy Ooty Radio Telescope (ORT) is being reconfigured as a 264-element synthesis telescope, called the Ooty Wide Field Array (OWFA). Its antenna elements are the contiguous 1.92 m sections of the parabolic cylinder. It will operate in a 38-MHz frequency band centred at 326.5 MHz and will be equipped with a digital receiver including a 264-element spectral correlator with a spectral resolution of 48 kHz. OWFA is designed to retain the benefits of equatorial mount, continuous 9-hour tracking ability and large collecting area of the legacy telescope and use of modern digital techniques to enhance the instantaneous field-of-view by more than an order of magnitude. OWFA has unique advantages for contemporary investigations related to large scale structure, transient events and space weather watch. In this paper, we describe the RF subsystems, digitizers and fibre optic communication of OWFA and highlight some specific aspects of the system relevant for the observations planned during the initial operation.

The atmospheric transparency of Telescope Array experiment from LIDAR

NASA Astrophysics Data System (ADS)

Tomida, T.

2011-09-01

UV fluorescence light generated by an air shower is scattered and lost along the path of transmission to the telescope. The main scattering processes are Rayleigh scattering by molecules and scattering by aerosols in an atmosphere. In the Telescope Array Experiment, we make use of LIDAR (LIght Detection And Ranging), which observes the back-scattered light of laser. The LIDAR system is operated before the beginning and after the end of an FD observation, twice a night. The typical transparency of aerosols on clear night is obtained two years observation from September, 2007. The extinction coefficient of aerosols (αAS) at ground level are 0.040-0.013+0.036 km-1. The dependence of typical aerosols on height above ground level (1450 m a.s.l.) can be express by two exponential components as following: αAS(h) = 0.021 exp(-h/0.2)+0.019 exp(-h/1.9). The atmospheric transparency measured with the LIDAR system in TA site is discussed in this paper.

Sensitivity of the Cherenkov Telescope Array to the detection of a dark matter signal in comparison to direct detection and collider experiments

DOE PAGES

Balazs, Csaba; Conrad, Jan; Farmer, Ben; ...

2017-10-04

Imaging atmospheric Cherenkov telescopes (IACTs) that are sensitive to potential γ-ray signals from dark matter (DM) annihilation above ~50 GeV will soon be superseded by the Cherenkov Telescope Array (CTA). CTA will have a point source sensitivity an order of magnitude better than currently operating IACTs and will cover a broad energy range between 20 GeV and 300 TeV. Using effective field theory and simplified models to calculate γ-ray spectra resulting from DM annihilation, we compare the prospects to constrain such models with CTA observations of the Galactic center with current and near-future measurements at the Large Hadron Collider (LHC)more » and direct detection experiments. Here, for DM annihilations via vector or pseudoscalar couplings, CTA observations will be able to probe DM models out of reach of the LHC, and, if DM is coupled to standard fermions by a pseudoscalar particle, beyond the limits of current direct detection experiments.« less

The design of the local monitor and control system of SKA dishes

NASA Astrophysics Data System (ADS)

Schillirò, F.; Baldini, V.; Becciani, U.; Cirami, R.; Costa, A.; Ingallinera, A.; Marassi, A.; Nicotra, G.; Nocita, C.; Riggi, S.; Trigilio, C.

2016-08-01

The Square Kilometer Array (SKA) project aims at building the world's largest radio observatory to observe the sky with unprecedented sensitivity and collecting area. In the first phase of the project (SKA1), an array of dishes, SKA1-MID, will be built in South Africa. It will consist of 133 15m-dishes, which will include the MeerKAT array, for the 0.350-20 GHz frequency band observations. Each antenna will be provided with a local monitor and control system (LMC), enabling operations both to the Telescope Manager remote system, and to the engineers and maintenance staff; it provides different environment for the telescope control (positioning, pointing, observational bands), metadata collection for monitoring and database storaging, operational modes and functional states management for all the telescope capabilities. In this paper we present the LMC software architecture designed for the detailed design phase (DD), where we describe functional and physical interfaces with monitored and controlled sub-elements, and highlight the data flow between each LMC modules and its sub-element controllers from one side, and Telescope Manager on the other side. We also describe the complete Product Breakdown Structure (PBS) created in order to optimize resources allocation in terms of calculus and memory, able to perform required task for each element according to the proper requirements. Among them, time response and system reliability are the most important, considering the complexity of SKA dish network and its isolated placement. Performances obtained by software implementation using TANGO framework will be discussed, matching them with technical requirements derived by SKA science drivers.

SPIDER: Next Generation Chip Scale Imaging Sensor Update

NASA Astrophysics Data System (ADS)

Duncan, A.; Kendrick, R.; Ogden, C.; Wuchenich, D.; Thurman, S.; Su, T.; Lai, W.; Chun, J.; Li, S.; Liu, G.; Yoo, S. J. B.

2016-09-01

The Lockheed Martin Advanced Technology Center (LM ATC) and the University of California at Davis (UC Davis) are developing an electro-optical (EO) imaging sensor called SPIDER (Segmented Planar Imaging Detector for Electro-optical Reconnaissance) that seeks to provide a 10x to 100x size, weight, and power (SWaP) reduction alternative to the traditional bulky optical telescope and focal-plane detector array. The substantial reductions in SWaP would reduce cost and/or provide higher resolution by enabling a larger-aperture imager in a constrained volume. Our SPIDER imager replaces the traditional optical telescope and digital focal plane detector array with a densely packed interferometer array based on emerging photonic integrated circuit (PIC) technologies that samples the object being imaged in the Fourier domain (i.e., spatial frequency domain), and then reconstructs an image. Our approach replaces the large optics and structures required by a conventional telescope with PICs that are accommodated by standard lithographic fabrication techniques (e.g., complementary metal-oxide-semiconductor (CMOS) fabrication). The standard EO payload integration and test process that involves precision alignment and test of optical components to form a diffraction limited telescope is, therefore, replaced by in-process integration and test as part of the PIC fabrication, which substantially reduces associated schedule and cost. This paper provides an overview of performance data on the second-generation PIC for SPIDER developed under the Defense Advanced Research Projects Agency (DARPA)'s SPIDER Zoom research funding. We also update the design description of the SPIDER Zoom imaging sensor and the second-generation PIC (high- and low resolution versions).

Testbed Experiment for SPIDER: A Photonic Integrated Circuit-based Interferometric imaging system

NASA Astrophysics Data System (ADS)

Badham, K.; Duncan, A.; Kendrick, R. L.; Wuchenich, D.; Ogden, C.; Chriqui, G.; Thurman, S. T.; Su, T.; Lai, W.; Chun, J.; Li, S.; Liu, G.; Yoo, S. J. B.

The Lockheed Martin Advanced Technology Center (LM ATC) and the University of California at Davis (UC Davis) are developing an electro-optical (EO) imaging sensor called SPIDER (Segmented Planar Imaging Detector for Electro-optical Reconnaissance) that seeks to provide a 10x to 100x size, weight, and power (SWaP) reduction alternative to the traditional bulky optical telescope and focal-plane detector array. The substantial reductions in SWaP would reduce cost and/or provide higher resolution by enabling a larger-aperture imager in a constrained volume. Our SPIDER imager replaces the traditional optical telescope and digital focal plane detector array with a densely packed interferometer array based on emerging photonic integrated circuit (PIC) technologies that samples the object being imaged in the Fourier domain (i.e., spatial frequency domain), and then reconstructs an image. Our approach replaces the large optics and structures required by a conventional telescope with PICs that are accommodated by standard lithographic fabrication techniques (e.g., complementary metal-oxide-semiconductor (CMOS) fabrication). The standard EO payload integration and test process that involves precision alignment and test of optical components to form a diffraction limited telescope is, therefore, replaced by in-process integration and test as part of the PIC fabrication, which substantially reduces associated schedule and cost. In this paper we describe the photonic integrated circuit design and the testbed used to create the first images of extended scenes. We summarize the image reconstruction steps and present the final images. We also describe our next generation PIC design for a larger (16x area, 4x field of view) image.

The ICT monitoring system of the ASTRI SST-2M prototype proposed for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Gianotti, F.; Bruno, P.; Tacchini, A.; Conforti, V.; Fioretti, V.; Tanci, C.; Grillo, A.; Leto, G.; Malaguti, G.; Trifoglio, M.

2016-08-01

In the framework of the international Cherenkov Telescope Array (CTA) observatory, the Italian National Institute for Astrophysics (INAF) has developed a dual mirror, small sized, telescope prototype (ASTRI SST-2M), installed in Italy at the INAF observing station located at Serra La Nave, Mt. Etna. The ASTRI SST-2M prototype is the basis of the ASTRI telescopes that will form the mini-array proposed to be installed at the CTA southern site during its preproduction phase. This contribution presents the solutions implemented to realize the monitoring system for the Information and Communication Technology (ICT) infrastructure of the ASTRI SST-2M prototype. The ASTRI ICT monitoring system has been implemented by integrating traditional tools used in computer centers, with specific custom tools which interface via Open Platform Communication Unified Architecture (OPC UA) to the Alma Common Software (ACS) that is used to operate the ASTRI SST-2M prototype. The traditional monitoring tools are based on Simple Network Management Protocol (SNMP) and commercial solutions and features embedded in the devices themselves. They generate alerts by email and SMS. The specific custom tools convert the SNMP protocol into the OPC UA protocol and implement an OPC UA server. The server interacts with an OPC UA client implemented in an ACS component that, through the ACS Notification Channel, sends monitor data and alerts to the central console of the ASTRI SST-2M prototype. The same approach has been proposed also for the monitoring of the CTA onsite ICT infrastructures.

The upgrade of the H.E.S.S. cameras

NASA Astrophysics Data System (ADS)

Giavitto, Gianluca; Ashton, Terry; Balzer, Arnim; Berge, David; Brun, Francois; Chaminade, Thomas; Delagnes, Eric; Fontaine, Gerard; Füßling, Matthias; Giebels, Berrie; Glicenstein, Jean-Francois; Gräber, Tobias; Hinton, Jim; Jahnke, Albert; Klepser, Stefan; Kossatz, Marko; Kretzschmann, Axel; Lefranc, Valentin; Leich, Holger; Lüdecke, Hartmut; Lypova, Iryna; Manigot, Pascal; Marandon, Vincent; Moulin, Emmanuel; Naurois, Mathieu de; Nayman, Patrick; Ohm, Stefan; Penno, Marek; Ross, Duncan; Salek, David; Schade, Markus; Schwab, Thomas; Simoni, Rachel; Stegmann, Christian; Steppa, Constantin; Thornhill, Julian; Toussnel, Francois

2017-12-01

The High Energy Stereoscopic System (HESS) is an array of imaging atmospheric Cherenkov telescopes (IACTs) located in the Khomas highland in Namibia. It was built to detect Very High Energy (VHE > 100 GeV) cosmic gamma rays. Since 2003, HESS has discovered the majority of the known astrophysical VHE gamma-ray sources, opening a new observational window on the extreme non-thermal processes at work in our universe. HESS consists of four 12-m diameter Cherenkov telescopes (CT1-4), which started data taking in 2002, and a larger 28-m telescope (CT5), built in 2012, which lowers the energy threshold of the array to 30 GeV . The cameras of CT1-4 are currently undergoing an extensive upgrade, with the goals of reducing their failure rate, reducing their readout dead time and improving the overall performance of the array. The entire camera electronics has been renewed from ground-up, as well as the power, ventilation and pneumatics systems, and the control and data acquisition software. Only the PMTs and their HV supplies have been kept from the original cameras. Novel technical solutions have been introduced, which will find their way into some of the Cherenkov cameras foreseen for the next-generation Cherenkov Telescope Array (CTA) observatory. In particular, the camera readout system is the first large-scale system based on the analog memory chip NECTAr, which was designed for CTA cameras. The camera control subsystems and the control software framework also pursue an innovative design, exploiting cutting-edge hardware and software solutions which excel in performance, robustness and flexibility. The CT1 camera has been upgraded in July 2015 and is currently taking data; CT2-4 have been upgraded in fall 2016. Together they will assure continuous operation of HESS at its full sensitivity until and possibly beyond the advent of CTA. This contribution describes the design, the testing and the in-lab and on-site performance of all components of the newly upgraded HESS camera.

The LUVOIR Surveyor: Design Update and Technology Needs

NASA Technical Reports Server (NTRS)

Bolcar, Matthew R.

2017-01-01

The Large UV/Optical/Infrared (LUVOIR) Surveyor is one of four large mission concepts being studied by NASA in preparation for the 2020 Decadal Study in Astrophysics. LUVOIR builds upon the legacy of the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), and the Wide-Field Infrared Survey Telescope (WFIRST) in that it is a large, segmented aperture space telescope spanning the Far-UV to Near-IR wavelength range, and will perform a broad array of general astrophysics as well as directly detect and characterize habitable exoplanets around nearby sun-like stars. In this talk, we present an overview of the LUVOIR Architecture, a 15-m class telescope with four serviceable instruments. We highlight technologies needed to enable this mission, as well as technologies that may potentially enhance LUVOIR science mission.

Report of the Science Working Group: Science with a lunar optical interferometer

NASA Technical Reports Server (NTRS)

1992-01-01

Resolution is the greatest constraint in observational astronomy. The Earth's atmosphere causes on optical image to blur to about 1 arcsec or greater. Interferometric techniques have been developed to overcome atmospheric limitations for both filled aperture conventional telescopes and for partially filled aperture telescopes, such as the Michelson or the radio interferometer. The Hubble Space Telescope (HST) represents the first step toward space based optical astronomy. The HST represents an immediate short term evolution of observational optical astronomy. A longer time scale of evolution is focused on and the benefits are considered to astronomy of placing an array of telescopes on the Moon at a time when a permanent base may exist there.

Radio telescope search for the resonant conversion of cold dark matter axions from the magnetized astrophysical sources

NASA Astrophysics Data System (ADS)

Huang, Fa Peng; Kadota, Kenji; Sekiguchi, Toyokazu; Tashiro, Hiroyuki

2018-06-01

We study the conditions for the adiabatic resonant conversion of the cold dark matter (CDM) axions into photons in the astrophysically sourced strong magnetic fields such as those in the neutron star magnetosphere. We demonstrate the possibility that the forthcoming radio telescopes such as the SKA (Square Kilometre Array) can probe those photon signals from the CDM axions.

Seeing Stars - Intensity Interferometry in the Laboratory & on the Ground

NASA Astrophysics Data System (ADS)

Carlile, Colin; Dravins, Dainis

2018-04-01

In many ways it is a golden age for astronomy. Spectacular new discoveries, for example the detection of gravitational waves, are very dependent upon instrumental development. The specific instrument development we propose, Intensity Interferometry (II), aims toimprove the spatial resolution of optical telescopes by 100x to 50µas [1]. This is impractical to achieve by increasing the size of telescopes or by extending the capabilities of phase interferometry. II, if implemented on the Cherenkov Telescope Array (CTA) currently being installed in La Palma and Paranal, would record the light intensity – the photon train - from many different telescopes, up to 2 km apart, on a nanosecond timescale and compare them. The signal from the many pairs of telescopes would quantify the degree of correlation by extracting the second-order correlation function, and thus create an image. This is not a real space image. However we can invert the data by Fourier Transform and create a real image. The more telescopes, the better resolved and more physical is the image, enabling the study of sunspots on nearby stars; orbiting binary stars; or exoplanets traversing the disc of their own star. We understand the Sun well but we have little experimental knowledge of how representative it is of main sequence stars. To test the II method, at Lund Observatory we have set up a laboratory analogue comprising ten small telescopes observing an artificial star created by light from a laser. The method has been shown to work [2] and the telescope array has now been extended to two dimensions. We are in discussion with other groups to explore the possibility of implementing this method on real telescopes observing actual stars. We plan to do this with the prototype Small Size Telescopes being built by groups in Europe, and ultimately with the CTA itself. A Science Working Group for II has now been set up within the CTA Consortium, of which Lund University is an integral part. A Letter of Intent has been sent to CTA expressing these intentions. An attractive aspect of II is its complementarity to the principle goal of CTA - the exploration of high energy cosmic rays via the Cherenkov light they generate in the atmosphere. This can only be observed under the most demanding atmospheric conditions whereas II can be recorded when conditions are poor: with a bright Moon, during periods of turbulence; in hazy conditions; or after dusk and before dawn. Two further advantages of implementing an II option on CTA are the minimal marginal costs incurred to an already 400M€ investment and, secondly, that even a few telescopes would produce unique scientific results even in the early days when the CTA array is far from complete. [1] Dainis Dravins and Colin Carlile, SPIE Newsroom (2016), http://spie.org/newsroom/6504-kilometer-baseline-optical-intensity-interferometry-for-stellar-surface-observations [2] D. Dravins, T. Lagadec, P.D. Nuñez, Nature Communications 6, 6852 (2015)

The Fourier-Kelvin Stellar Interferometer Mission Concept

NASA Technical Reports Server (NTRS)

Danchi, W. C.; Allen, R.; Benford, D.; Gezari, D.; Leisawitz, D.; Mundy, L.; Oegerle, William (Technical Monitor)

2002-01-01

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging interferometer for the mid-infrared spectral region (5-30 microns). FKSI is conceived as a scientific and technological precursor to TPF as well as Space Infrared Interferometric Telescope (SPIRIT), Submillimeter Probe Evolution of Cosmic Structure (SPECS), and Single Aperture for Infrared Observatory (SAFIR). It will also be a high angular resolution system complementary to Next Generation Space Telescope (NGST). The scientific emphasis of the mission is on the evolution of protostellar systems, from just after the collapse of the precursor molecular cloud core, through the formation of the disk surrounding the protostar, the formation of planets in the disk, and eventual dispersal of the disk material. FKSI will also search for brown dwarfs and Jupiter mass and smaller planets, and could also play a very powerful role in the investigation of the structure of active galactic nuclei and extra-galactic star formation. We are in the process of studying alternative interferometer architectures and beam combination techniques, and evaluating the relevant science and technology tradeoffs. Some of the technical challenges include the development of the cryocooler systems necessary for the telescopes and focal plane array, light and stiff but well-damped truss systems to support the telescopes, and lightweight and coolable optical telescopes. The goal of the design study is to determine if a mid-infrared interferometry mission can be performed within the cost and schedule requirements of a Discovery class mission. At the present time we envision the FKSI as comprised of five one meter diameter telescopes arranged along a truss structure in a linear non-redundant array, cooled to 35 K. A maximum baseline of 20 meters gives a nominal resolution of 26 mas at 5 microns. Using a Fizeau beam combination technique, a simple focal plane camera could be used to obtain both Fourier and spectral data simultaneously for a given orientation of the array. The spacecraft will be rotated to give sufficient Fourier data to reconstruct complex images of a broad range of astrophysical sources.

PLC-controlled cryostats for the BlackGEM and MeerLICHT detectors

NASA Astrophysics Data System (ADS)

Raskin, Gert; Morren, Johan; Pessemier, Wim; Bloemen, Steven; Klein-Wolt, Marc; Roelfsema, Ronald; Groot, Paul; Aerts, Conny

2016-08-01

BlackGEM is an array of telescopes, currently under development at the Radboud University Nijmegen and at NOVA (Netherlands Research School for Astronomy). It targets the detection of the optical counterparts of gravitational waves. The first three BlackGEM telescopes are planned to be installed in 2018 at the La Silla observatory (Chile). A single prototype telescope, named MeerLICHT, will already be commissioned early 2017 in Sutherland (South Africa) to provide an optical complement for the MeerKAT radio array. The BlackGEM array consists of, initially, a set of three robotic 65-cm wide-field telescopes. Each telescope is equipped with a single STA1600 CCD detector with 10.5k x 10.5k 9-micron pixels that covers a 2.7 square degrees field of view. The cryostats for housing these detectors are developed and built at the KU Leuven University (Belgium). The operational model of BlackGEM requires long periods of reliable hands-off operation. Therefore, we designed the cryostats for long vacuum hold time and we make use of a closed-cycle cooling system, based on Polycold PCC Joule-Thomson coolers. A single programmable logic controller (PLC) controls the cryogenic systems of several BlackGEM telescopes simultaneously, resulting in a highly reliable, cost-efficient and maintenance-friendly system. PLC-based cryostat control offers some distinct advantages, especially for a robotic facility. Apart of temperature monitoring and control, the PLC also monitors the vacuum quality, the power supply and the status of the PCC coolers (compressor power consumption and temperature, pressure in the gas lines, etc.). Furthermore, it provides an alarming system and safe and reproducible procedures for automatic cool down and warm up. The communication between PLC and higher-level software takes place via the OPC-UA protocol, offering a simple to implement, yet very powerful interface. Finally, a touch-panel display on the PLC provides the operator with a user-friendly and robust technical interface. In this contribution, we present the design of the BlackGEM cryostats and of the PLC-based control system.

Two-dimensional photon-counting detector arrays based on microchannel array plates

NASA Technical Reports Server (NTRS)

Timothy, J. G.; Bybee, R. L.

1975-01-01

The production of simple and rugged photon-counting detector arrays has been made possible by recent improvements in the performance of the microchannel array plate (MCP) and by the parallel development of compatible electronic readout systems. The construction of proximity-focused MCP arrays of novel design in which photometric information from (n x m) picture elements is read out with a total of (n + m) amplifier and discriminator circuits is described. Results obtained with a breadboard (32 x 32)-element array employing 64 charge-sensitive amplifiers are presented, and the application of systems of this type in spectrometers and cameras for use with ground-based telescopes and on orbiting spacecraft discussed.

The CHARA Array Database

NASA Astrophysics Data System (ADS)

Jones, Jeremy; Schaefer, Gail; ten Brummelaar, Theo; Gies, Douglas; Farrington, Christopher

2018-01-01

We are building a searchable database for the CHARA Array data archive. The Array consists of six telescopes linked together as an interferometer, providing sub-milliarcsecond resolution in the optical and near-infrared. The Array enables a variety of scientific studies, including measuring stellar angular diameters, imaging stellar shapes and surface features, mapping the orbits of close binary companions, and resolving circumstellar environments. This database is one component of an NSF/MSIP funded program to provide open access to the CHARA Array to the broader astronomical community. This archive goes back to 2004 and covers all the beam combiners on the Array. We discuss the current status of and future plans for the public database, and give directions on how to access it.

Astronaut Story Musgrave during deployment of solar array panels on HST

NASA Image and Video Library

1993-12-09

STS061-48-027 (9 Dec 1993) --- Astronaut F. Story Musgrave moves about in the Space Shuttle Endeavour's cargo bay during the deployment of the solar array panels on the Hubble Space Telescope (HST) during the final of five STS-61 space walks. The left hand of astronaut Jeffrey A. Hoffman appears at lower left corner.

HST Solar Arrays photographed by Electronic Still Camera

NASA Technical Reports Server (NTRS)

1993-01-01

This close-up view of one of two Solar Arrays (SA) on the Hubble Space Telescope (HST) was photographed with an Electronic Still Camera (ESC), and downlinked to ground controllers soon afterward. Electronic still photography is a technology which provides the means for a handheld camera to electronically capture and digitize an image with resolution approaching film quality.

Optical Telescope System-Level Design Considerations for a Space-Based Gravitational Wave Mission

NASA Technical Reports Server (NTRS)

Livas, Jeffrey C.; Sankar, Shannon R.

2016-01-01

The study of the Universe through gravitational waves will yield a revolutionary new perspective on the Universe, which has been intensely studied using electromagnetic signals in many wavelength bands. A space-based gravitational wave observatory will enable access to a rich array of astrophysical sources in the measurement band from 0.1 to 100 mHz, and nicely complement observations from ground-based detectors as well as pulsar timing arrays by sampling a different range of compact object masses and astrophysical processes. The observatory measures gravitational radiation by precisely monitoring the tiny change in the proper distance between pairs of freely falling proof masses. These masses are separated by millions of kilometers and, using a laser heterodyne interferometric technique, the change in their proper separation is detected to approx. 10 pm over timescales of 1000 seconds, a fractional precision of better than one part in 10(exp 19). Optical telescopes are essential for the implementation of this precision displacement measurement. In this paper we describe some of the key system level design considerations for the telescope subsystem in a mission context. The reference mission for this purpose is taken to be the enhanced Laser Interferometry Space Antenna mission (eLISA), a strong candidate for the European Space Agency's Cosmic Visions L3 launch opportunity in 2034. We will review the flow-down of observatory level requirements to the telescope subsystem, particularly pertaining to the effects of telescope dimensional stability and scattered light suppression, two performance specifications which are somewhat different from the usual requirements for an image forming telescope.

Observatories Combine to Crack Open the Crab Nebula

NASA Image and Video Library

2017-12-08

Astronomers have produced a highly detailed image of the Crab Nebula, by combining data from telescopes spanning nearly the entire breadth of the electromagnetic spectrum, from radio waves seen by the Karl G. Jansky Very Large Array (VLA) to the powerful X-ray glow as seen by the orbiting Chandra X-ray Observatory. And, in between that range of wavelengths, the Hubble Space Telescope's crisp visible-light view, and the infrared perspective of the Spitzer Space Telescope. This video starts with a composite image of the Crab Nebula, a supernova remnant that was assembled by combining data from five telescopes spanning nearly the entire breadth of the electromagnetic spectrum: the Very Large Array, the Spitzer Space Telescope, the Hubble Space Telescope, the XMM-Newton Observatory, and the Chandra X-ray Observatory. The video dissolves to the red-colored radio-light view that shows how a neutron star’s fierce “wind” of charged particles from the central neutron star energized the nebula, causing it to emit the radio waves. The yellow-colored infrared image includes the glow of dust particles absorbing ultraviolet and visible light. The green-colored Hubble visible-light image offers a very sharp view of hot filamentary structures that permeate this nebula. The blue-colored ultraviolet image and the purple-colored X-ray image shows the effect of an energetic cloud of electrons driven by a rapidly rotating neutron star at the center of the nebula. Read more: go.nasa.gov/2r0s8VC Credits: NASA, ESA, J. DePasquale (STScI)

Large format imaging arrays for the Atacama Cosmology Telescope

NASA Technical Reports Server (NTRS)

Chervenak, J. A.; Wollack, E. J.; Marraige, T.; Staggs, S.; Niemack, M.; Doriese, B.

2006-01-01

We describe progress in the fabrication, characterization, and production of detector arrays for the Atacama Cosmology Telescope (ACT). The completed ACT instrument is specified to image simultaneously at 145, 225, and 265 GHz using three 32x32 filled arrays of superconducting transition edge sensors (TES) read out with time-division-multiplexed SQUID amplifiers. We present details of the pixel design and testing including the optimization of the electrical parameters for multiplexed readout. Using geometric noise suppression and careful tuning of operation temperature and device bias resistance, the excess noise in the TES devices is balanced with detector speed for interfacing with the ACT optics. The design also accounts for practical tolerances such as transition temperature gradients and scatter that occur in the production of multiple wafers to populate fully the kilopixel cameras. We have developed an implanted absorber layer compatible with our silicon-on-insulator process that allows for tunable optical resistance with requisite on-wafer uniformity and wafer-to-wafer reproducibility. Arrays of 32 elements have been tested in the laboratory environment including electrical, optical, and multiplexed performance. Given this pixel design, optical tests and modeling are used to predict the performance of the filled array under anticipated viewing conditions. Integration of the filled array of pixels with a tuned backshort and dielectric plate in front of the array maximize absorption and the focal plane and suppress reflections. A mechanical design for the build of the full structure is completed and we report on progress toward the construction of a prototype array for first light on the ACT.

Study of Radio sources and interferences detected by MEXART

NASA Astrophysics Data System (ADS)

Villanueva Hernandez, P.; Gonzalez Esparza, J. A.; Carrillo, A.; Andrade, E.; Jeyacumar, S.; Kurtz, S.

2007-05-01

The Mexican Array Radio Telescope (MEXART) is a radio telescope that will perform studies of solar wind disturbances using the Interplanetary Scintillation (IPS) technique. The radiotelescope is its final calibration stage, and in this work we report two testings: the interference signals detected around the operation frequency, and the transit of the main radio sources detected by individual lines of 64 dipoles. These radio sources are: Sun, Casiopea, Crab nebula, Cygnus and Virgo. These testings allow us to know the response of the array elements in order to calibrate them. The final operation of the MEXART requires that the signal detected and transmitted by each East-West line of 64 dipoles arrives at the butler matrix (control room) with the same phase and amplitude.

The bursts of high energy events observed by the telescope array surface detector

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kishigami, S.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Onogi, R.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Saito, K.; Saito, Y.; Sakaki, N.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Sekino, K.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2017-08-01

The Telescope Array (TA) experiment is designed to detect air showers induced by ultra high energy cosmic rays. The TA ground Surface particle Detector (TASD) observed several short-time bursts of air shower like events. These bursts are not likely due to chance coincidence between single shower events. The expectation of chance coincidence is less than 10-4 for five-year's observation. We checked the correlation between these bursts of events and lightning data, and found evidence for correlations in timing and position. Some features of the burst events are similar to those of a normal cosmic ray air shower, and some are not. On this paper, we report the observed bursts of air shower like events and their correlation with lightning.

New Focal Plane Array Controller for the Instruments of the Subaru Telescope

NASA Astrophysics Data System (ADS)

Nakaya, Hidehiko; Komiyama, Yutaka; Miyazaki, Satoshi; Yamashita, Takuya; Yagi, Masafumi; Sekiguchi, Maki

2006-03-01

We have developed a next-generation data acquisition system, MESSIA5 (Modularized Extensible System for Image Acquisition), which comprises the digital part of a focal plane array controller. The new data acquisition system was constructed based on a 64 bit, 66 MHz PCI (peripheral component interconnect) bus architecture and runs on an x86 CPU computer with (non-real-time) Linux. The system, including the CPU board, is placed at the telescope focus, and standard gigabit Ethernet is adopted for the data transfer, as opposed to a dedicated fiber link. During the summer of 2002, we installed the new system for the first time on the Subaru prime-focus camera Suprime-Cam and successfully improved the observing performance.

The Fourier-Kelvin Stellar Interferometer (FKSI): A Discovery Class TPF/DARWIN Pathfinder Mission Concept

NASA Technical Reports Server (NTRS)

Danchi, W. C.; Allen, R. J.; Benford, D. J.; Deming, D.; Gezan, D. Y.; Kuchner, M.; Leisawitz, D. T.; Linfield, R.; Millan-Gabet, R.; Monnier, J. D.

2003-01-01

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging and nulling interferometer for the mid-infrared spectral region (5-30 microns). FKSI is conceived as a scientific and technological pathfinder to TPF/DARWIN as well as SPIRIT, SPECS, and SAFIR. It will also be a high angular resolution system complementary to NGST. The scientific emphasis of the mission is on the evolution of protostellar systems, from just after the collapse of the precursor molecular cloud core, through the formation of the disk surrounding the protostar, the formation of planets in the disk, and eventual dispersal of the disk material. FKSI will also search for brown dwarfs and Jupiter mass and smaller planets, and could also play a very powerful role in the investigation of the structure of active galactic nuclei and extra-galactic star formation. We have been studying alternative interferometer architectures and beam combination techniques, and evaluating the relevant science and technology tradeoffs. Some of the technical challenges include the development of the cryocooler systems necessary for the telescopes and focal plane array, light and stiff but well-damped truss systems to support the telescopes, and lightweight and coolable optical telescopes. We present results of detailed design studies of the FKSI starting with a design consisting of five one meter diameter telescopes arranged along a truss structure in a linear non-redundant array, cooled to 35 K. A maximum baseline of 20 meters gives a nominal resolution of 26 mas at 5 microns. Using a Fizeau beam combination technique, a simple focal plane camera could be used to obtain both Fourier and spectral data simultaneously for a given orientation of the array. The spacecraft will be rotated to give sufficient Fourier data to reconstruct complex images of a broad range of astrophysical sources. Alternative and simpler three and two telescope designs emphasizing nulling and spectroscopy also have been investigated and will be discussed.

The Basic Theoretical Framework

NASA Astrophysics Data System (ADS)

Loeb, Abraham

Cosmology is by now a mature experimental science. We are privileged to live at a time when the story of genesis (how the Universe started and developed) can be critically explored by direct observations. Looking deep into the Universe through powerful telescopes, we can see images of the Universe when it was younger because of the finite time it takes light to travel to us from distant sources. Existing data sets include an image of the Universe when it was 0.4 million years old (in the form of the cosmic microwave background), as well as images of individual galaxies when the Universe was older than a billion years. But there is a serious challenge: in between these two epochs was a period when the Universe was dark, stars had not yet formed, and the cosmic microwave background no longer traced the distribution of matter. And this is precisely the most interesting period, when the primordial soup evolved into the rich zoo of objects we now see. The observers are moving ahead along several fronts. The first involves the construction of large infrared telescopes on the ground and in space, that will provide us with new photos of the first galaxies. Current plans include ground-based telescopes which are 24-42 m in diameter, and NASA's successor to the Hubble Space Telescope, called the James Webb Space Telescope. In addition, several observational groups around the globe are constructing radio arrays that will be capable of mapping the three-dimensional distribution of cosmic hydrogen in the infant Universe. These arrays are aiming to detect the long-wavelength (redshifted 21-cm) radio emission from hydrogen atoms. The images from these antenna arrays will reveal how the non-uniform distribution of neutral hydrogen evolved with cosmic time and eventually was extinguished by the ultra-violet radiation from the first galaxies. Theoretical research has focused in recent years on predicting the expected signals for the above instruments and motivating these ambitious observational projects.

MeerLICHT and BlackGEM: custom-built telescopes to detect faint optical transients

NASA Astrophysics Data System (ADS)

Bloemen, Steven; Groot, Paul; Woudt, Patrick; Klein Wolt, Marc; McBride, Vanessa; Nelemans, Gijs; Körding, Elmar; Pretorius, Margaretha L.; Roelfsema, Ronald; Bettonvil, Felix; Balster, Harry; Bakker, Roy; Dolron, Peter; van Elteren, Arjen; Elswijk, Eddy; Engels, Arno; Fender, Rob; Fokker, Marc; de Haan, Menno; Hagoort, Klaas; de Hoog, Jasper; ter Horst, Rik; van der Kevie, Giel; Kozłowski, Stanisław; Kragt, Jan; Lech, Grzegorz; Le Poole, Rudolf; Lesman, Dirk; Morren, Johan; Navarro, Ramon; Paalberends, Willem-Jelle; Paterson, Kerry; Pawłaszek, Rafal; Pessemier, Wim; Raskin, Gert; Rutten, Harrie; Scheers, Bart; Schuil, Menno; Sybilski, Piotr W.

2016-07-01

We present the MeerLICHT and BlackGEM telescopes, which are wide-field optical telescopes that are currently being built to study transient phenomena, gravitational wave counterparts and variable stars. The telescopes have 65 cm primary mirrors and a 2.7 square degree field-of-view. The MeerLICHT and BlackGEM projects have different science goals, but will use identical telescopes. The first telescope, MeerLICHT, will be commissioned at Sutherland (South Africa) in the first quarter of 2017. It will co-point with MeerKAT to collect optical data commensurate with the radio observations. After careful analysis of MeerLICHT's performance, three telescopes of the same type will be commissioned in La Silla (Chile) in 2018 to form phase I of the BlackGEM array. BlackGEM aims at detecting and characterizing optical counterparts of gravitational wave events detected by Advanced LIGO and Virgo. In this contribution we present an overview of the science goals, the design and the status of the two projects.

Astronomical Verification of a Stabilized Frequency Reference Transfer System for the Square Kilometer Array

NASA Astrophysics Data System (ADS)

Gozzard, David R.; Schediwy, Sascha W.; Dodson, Richard; Rioja, María J.; Hill, Mike; Lennon, Brett; McFee, Jock; Mirtschin, Peter; Stevens, Jamie; Grainge, Keith

2017-07-01

In order to meet its cutting-edge scientific objectives, the Square Kilometre Array (SKA) telescope requires high-precision frequency references to be distributed to each of its antennas. The frequency references are distributed via fiber-optic links and must be actively stabilized to compensate for phase noise imposed on the signals by environmental perturbations on the links. SKA engineering requirements demand that any proposed frequency reference distribution system be proved in “astronomical verification” tests. We present results of the astronomical verification of a stabilized frequency reference transfer system proposed for SKA-mid. The dual-receiver architecture of the Australia Telescope Compact Array was exploited to subtract the phase noise of the sky signal from the data, allowing the phase noise of observations performed using a standard frequency reference, as well as the stabilized frequency reference transfer system transmitting over 77 km of fiber-optic cable, to be directly compared. Results are presented for the fractional frequency stability and phase drift of the stabilized frequency reference transfer system for celestial calibrator observations at 5 and 25 GHz. These observations plus additional laboratory results for the transferred signal stability over a 166 km metropolitan fiber-optic link are used to show that the stabilized transfer system under test exceeds all SKA phase-stability requirements within a broad range of observing conditions. Furthermore, we have shown that alternative reference dissemination systems that use multiple synthesizers to supply reference signals to sub-sections of an array may limit the imaging capability of the telescope.

Hydrogen Epoch of Reinozation Array (HERA) Calibrated FFT Correlator Simulation

NASA Astrophysics Data System (ADS)

Salazar, Jeffrey David; Parsons, Aaron

2018-01-01

The Hydrogen Epoch of Reionization Array (HERA) project is an astronomical radio interferometer array with a redundant baseline configuration. Interferometer arrays are being used widely in radio astronomy because they have a variety of advantages over single antenna systems. For example, they produce images (visibilities) closely matching that of a large antenna (such as the Arecibo observatory), while both the hardware and maintenance costs are significantly lower. However, this method has some complications; one being the computational cost of correlating data from all of the antennas. A correlator is an electronic device that cross-correlates the data between the individual antennas; these are what radio astronomers call visibilities. HERA, being in its early stages, utilizes a traditional correlator system. The correlator cost scales as N2, where N is the number of antennas in the array. The purpose of a redundant baseline configuration array setup is for the use of a more efficient Fast Fourier Transform (FFT) correlator. FFT correlators scale as Nlog2N. The data acquired from this sort of setup, however, inherits geometric delay and uncalibrated antenna gains. This particular project simulates the process of calibrating signals from astronomical sources. Each signal “received” by an antenna in the simulation is given random antenna gain and geometric delay. The “linsolve” Python module was used to solve for the unknown variables in the simulation (complex gains and delays), which then gave a value for the true visibilities. This first version of the simulation only mimics a one dimensional redundant telescope array detecting a small amount of sources located in the volume above the antenna plane. Future versions, using GPUs, will handle a two dimensional redundant array of telescopes detecting a large amount of sources in the volume above the array.

Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST/AFTA

NASA Technical Reports Server (NTRS)

Gong, Qian; Mcelwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Stapelfeldt, Karl; Hilton, George; Sayson, Jorge Llop; Perrin, Marshall;

Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST-AFTA

NASA Technical Reports Server (NTRS)

Gong, Qian; Mcelwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Stapelfeldt, Karl; Hilton, George; Sayson, Jorge Llop; Perrin, Marshall;

Software for the First Station of the Long Wavelength Array

NASA Astrophysics Data System (ADS)

Dowell, J.; LWA Collaboration

2014-05-01

The first station of the Long Wavelength Array, LWA1, is currently operating at frequencies between 10 and 88 MHz in the Southwest United States. LWA1 consists of 256 cross-polarization dipole pairs spread over a 100 m aperture with five total-power outriggers up to ˜500 m from the center of the station. The raw voltages from the antennas are digitized and digitally combined to form four independent dual polarization beams, each with two tunings with up to 19.6 MHz of bandwidth. The telescope is designed to be a general-purpose instrument and supports a wide variety of science projects from the ionosphere to the cosmic dark ages. I will present the software behind this telescope and discuss the challenges associated with calibrating and maintaining an array of 261 dipoles. I will also discuss some of the challenges of handling the large data volume that LWA1 produces and how the LWA User Computing Facility helps address those problems.

Simulation of the hybrid Tunka Advanced International Gamma-ray and Cosmic ray Astrophysics (TAIGA)

NASA Astrophysics Data System (ADS)

Kunnas, M.; Astapov, I.; Barbashina, N.; Beregnev, S.; Bogdanov, A.; Bogorodskii, D.; Boreyko, V.; Brückner, M.; Budnev, N.; Chiavassa, A.; Chvalaev, O.; Dyachok, A.; Epimakhov, S.; Eremin, T.; Gafarov, A.; Gorbunov, N.; Grebenyuk, V.; Gress, O.; Gress, T.; Grinyuk, A.; Grishin, O.; Horns, D.; Ivanova, A.; Karpov, N.; Kalmykov, N.; Kazarina, Y.; Kindin, V.; Kirichkov, N.; Kiryuhin, S.; Kokoulin, R.; Kompaniets, K.; Konstantinov, E.; Korobchenko, A.; Korosteleva, E.; Kozhin, V.; Kuzmichev, L.; Lenok, V.; Lubsandorzhiev, B.; Lubsandorzhiev, N.; Mirgazov, R.; Mirzoyan, R.; Monkhoev, R.; Nachtigall, R.; Pakhorukov, A.; Panasyuk, M.; Pankov, L.; Perevalov, A.; Petrukhin, A.; Platonov, V.; Poleschuk, V.; Popescu, M.; Popova, E.; Porelli, A.; Porokhovoy, S.; Prosin, V.; Ptuskin, V.; Romanov, V.; Rubtsov, G. I.; Müger; Rybov, E.; Samoliga, V.; Satunin, P.; Saunkin, A.; Savinov, V.; Semeney, Yu; Shaibonov (junior, B.; Silaev, A.; Silaev (junior, A.; Skurikhin, A.; Slunecka, M.; Spiering, C.; Sveshnikova, L.; Tabolenko, V.; Tkachenko, A.; Tkachev, L.; Tluczykont, M.; Veslopopov, A.; Veslopopova, E.; Voronov, D.; Wischnewski, R.; Yashin, I.; Yurin, K.; Zagorodnikov, A.; Zirakashvili, V.; Zurbanov, V.

2015-08-01

Up to several 10s of TeV, Imaging Air Cherenkov Telescopes (IACTs) have proven to be the instruments of choice for GeV/TeV gamma-ray astronomy due to their good reconstrucion quality and gamma-hadron separation power. However, sensitive observations at and above 100 TeV require very large effective areas (10 km2 and more), which is difficult and expensive to achieve. The alternative to IACTs are shower front sampling arrays (non-imaging technique or timing-arrays) with a large area and a wide field of view. Such experiments provide good core position, energy and angular resolution, but only poor gamma-hadron separation. Combining both experimental approaches, using the strengths of both techniques, could optimize the sensitivity to the highest energies. The TAIGA project plans to combine the non-imaging HiSCORE [8] array with small (∼10m2) imaging telescopes. This paper covers simulation results of this hybrid approach.

Observational artifacts of Nuclear Spectroscopic Telescope Array: ghost rays and stray light

NASA Astrophysics Data System (ADS)

Madsen, Kristin K.; Christensen, Finn E.; Craig, William W.; Forster, Karl W.; Grefenstette, Brian W.; Harrison, Fiona A.; Miyasaka, Hiromasa; Rana, Vikram

2017-10-01

The Nuclear Spectroscopic Telescope Array (NuSTAR) launched in June 2012, flies two conical approximation Wolter-I mirrors at the end of a 10.15-m mast. The optics are coated with multilayers of Pt/C and W/Si that operate from 3 to 80 keV. Since the optical path is not shrouded, aperture stops are used to limit the field of view (FoV) from background and sources outside the FoV. However, there is still a sliver of sky (˜1.0 deg to 4.0 deg) where photons may bypass the optics altogether and fall directly on the detector array. We term these photons stray light. Additionally, there are also photons that do not undergo the focused double reflections in the optics, and we term these ghost rays. We present detailed analysis and characterization of these two components and discuss how they impact observations. Finally, we discuss how they could have been prevented and should be in future observatories.

Development of a Crosstalk Suppression Algorithm for KID Readout

NASA Astrophysics Data System (ADS)

Lee, Kyungmin; Ishitsuka, H.; Oguri, S.; Suzuki, J.; Tajima, O.; Tomita, N.; Won, Eunil; Yoshida, M.

2018-06-01

The GroundBIRD telescope aims to detect B-mode polarization of the cosmic microwave background radiation using the kinetic inductance detector array as a polarimeter. For the readout of the signal from detector array, we have developed a frequency division multiplexing readout system based on a digital down converter method. These techniques in general have the leakage problems caused by the crosstalks. The window function was applied in the field programmable gate arrays to mitigate the effect of these problems and tested it in algorithm level.

Planet detection and spectroscopy in visible light with a single aperture telescope and a nulling coronagraph

NASA Technical Reports Server (NTRS)

Shao, Michael; Serabyn, Eugene; Levine, Bruce Martin; Beichman, Charles; Liu, Duncan; Martin, Stefan; Orton, Glen; Mennesson, Bertrand; Morgan, Rhonda; Velusamy, Thangasamy;

Project MINERVA's Follow-up on Wide-Field, Small Telescope Photometry to Identify Exoplanets

NASA Astrophysics Data System (ADS)

Houghton, Audrey; Henderson, Morgan; Johnson, Samson; Sergi, Anthony; Eastman, Jason D.; Beatty, Thomas G.; McCrady, Nate

2017-01-01

MINERVA is an array of four 0.7-m telescopes equipped for high precision photometry and spectroscopy dedicated to exoplanet observations. During the first 18 months of science operations, MINERVA engaged in a program of photometric follow-up of potential transiting exoplanet targets identified by the Kilodegree Extremely Little Telescope (KELT). Robotically-obtained observations are passed through our data reduction pipeline and we extract light curves via differential photometry. We seek transit signals via a Markov chain Monte Carlo fit using BATMAN. We discuss results for over 100 target stars analyzed to date.

A dispersed fringe sensor prototype for the Giant Magellan Telescope

NASA Astrophysics Data System (ADS)

Frostig, Danielle; McLeod, Brian A.; Kopon, Derek

2017-01-01

The Giant Magellan Telescope (GMT) will employ seven 8.4m primary mirror segments and seven 1m secondary mirror segments to achieve the diffraction limit of a 25.4m aperture. One challenge of the GMT is keeping the seven pairs of mirror segments in phase. We present a conceptual opto mechanical design for a prototype dispersed fringe sensor. The prototype, which operates at J-band and incorporates an infrared avalanche photodiode array, will be deployed on the Magellan Clay Telescope to verify the sensitivity and accuracy of the planned GMT phasing sensor.

STS-109 Post Flight Presentation

NASA Astrophysics Data System (ADS)

2002-04-01

The STS-109 Post Flight presentation begins with Mission Specialists Nancy J. Currie, Michael J. Massimino, James H. Newman, and Richard M. Linnehan shown getting suited on launch day. Actual footage of the liftoff of the Space Shuttle Columbia is shown. Five spacewalks are performed to service the Hubble Space Telescope. Richard Linnehan and John Grunsfield are replacing solar arrays, connectors and power control units on the Hubble Space Telescope. Mission Specialist Nancy Currie will use Space Shuttle Columbia's robotic arm to grab the telescope, move it away from the orbiter and release it. A look at the coast of South America is also presented.

WCSC environmental process improvement study and demonstration program

NASA Technical Reports Server (NTRS)

Pawlick, Joseph F., Jr.; Severo, Orlando C.

1993-01-01

CSTAR's objective to develop commercial infrastructure is multi-faceted and includes diverse elements of the orbital and suborbital missions. Goals to this eight-month project with the WCSC are aimed at simplifying the environmental assessment, approval, and licensing process for commercial users. Included in this overarching set of goals are two specific processes: (1) air pollution control, and (2) the environmental assessment mechanism. Resolution of the potentially user unfriendly aspects of these environmentally sensitive criteria are readily transferable to other ranges where commercial space activity will be supported.

Artist concept of Hubble Space Telescope (HST) orbiting Earth after deploy

NASA Image and Video Library

1990-04-05

This artist concept shows the Hubble Space Telescope (HST) in operational configuration orbiting the Earth after its deploy from Discovery, Orbiter Vehicle (OV) 103 during STS-31. The high gain antennas (HGAs) and solar arrays (SAs) have been extended. HST's aperature door is open as it views the universe from a vantage point above the Earth's atmosphere. View provided by the Marshall Space Flight Center (MSFC).

Wide swath imaging spectrometer utilizing a multi-modular design

DOEpatents

Chrisp, Michael P.

2010-10-05

A wide swath imaging spectrometer utilizing an array of individual spectrometer modules in the telescope focal plane to provide an extended field of view. The spectrometer modules with their individual detectors are arranged so that their slits overlap with motion on the scene providing contiguous spatial coverage. The number of modules can be varied to take full advantage of the field of view available from the telescope.

Technology Advances at the NRAO Green Bank Telescope

NASA Astrophysics Data System (ADS)

Lockman, Felix James

2015-08-01

The 100 meter diameter Green Bank Telescope, with its large frequency coverage, great sensitivity, all-sky tracking, and location at a protected, radio-quiet site, offers a unique platform for technological advances in astronomical instrumentation that can yield an immediate scientific payoff.MUSTANG-1.5 is a feedhorn-coupled bolometer array for 3mm that has recently been installed on the telescope. It has 64 pixels (expandable to 223) and offers sensitivity to angular scales from 9" to more than 3' over a band from 75 GHz to 105 GHz. Its capabilities for science at 3mm are complimentary to, and in some cases superior to, those offered by ALMA. MUSTANG-1.5 is a collaboration between UPenn., NIST, NRAO, and other institutions.ARGUS is a 16-pixel focal plane array for millimeter spectroscopy that will be in use on the GBT in 2015. The array architecture is designed as a scalable technology pathfinder for larger arrays, but by itself it will provide major capabilities for spectroscopy from 75-107 GHz with 8" angular resolution over a wide field-of-view. It is a collaboration between Stanford Univ., Caltech, JPL, Univ. Maryland, Univ. Miami, and NRAO.FLAG is a prototype phased array receiver operating at 21cm wavelength that is under development for the GBT. It will produce multiple beams over a wide field of view with a sensitivity competitive with that of single-pixel receivers, allowing rapid astronomical surveys. FLAG is a collaboration between BYU, WVU, and NRAO.Also under development is a mm-wave phased array receiver for the GBT, designed to operate near 90 GHz as a prototype for very large format phased array receivers in the 3mm band. It is a collaboration between UMass and BYU.VEGAS is the new spectrometer for the GBT, offering multiple configurations well matched to GBT receivers from 1 to 100 GHz and suitable for use with focal plane arrays. It is a collaboration between UCal (Berkeley) and NRAO.The new receivers and spectrometers create extremely big data sets during both observation and later processing. Studies are under way at the GBT of data-streaming methodologies and pipeline processing techniques to meet the challenges posed by this new generation of instrumentation.

The software architecture of the camera for the ASTRI SST-2M prototype for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Sangiorgi, Pierluca; Capalbi, Milvia; Gimenes, Renato; La Rosa, Giovanni; Russo, Francesco; Segreto, Alberto; Sottile, Giuseppe; Catalano, Osvaldo

2016-07-01

The purpose of this contribution is to present the current status of the software architecture of the ASTRI SST-2M Cherenkov Camera. The ASTRI SST-2M telescope is an end-to-end prototype for the Small Size Telescope of the Cherenkov Telescope Array. The ASTRI camera is an innovative instrument based on SiPM detectors and has several internal hardware components. In this contribution we will give a brief description of the hardware components of the camera of the ASTRI SST-2M prototype and of their interconnections. Then we will present the outcome of the software architectural design process that we carried out in order to identify the main structural components of the camera software system and the relationships among them. We will analyze the architectural model that describes how the camera software is organized as a set of communicating blocks. Finally, we will show where these blocks are deployed in the hardware components and how they interact. We will describe in some detail, the physical communication ports and external ancillary devices management, the high precision time-tag management, the fast data collection and the fast data exchange between different camera subsystems, and the interfacing with the external systems.

Development in High-Density Cobra Fiber Positioners for the Subaru Telescope's Prime Focus Spectrometer

NASA Technical Reports Server (NTRS)

Fisher, Charles D.; Braun, David F.; Kaluzny, Joel V.; Seiffert, Mic D.; Dekany, Richard G.; Ellis, Richard S.; Smith, Roger S.

2012-01-01

The Prime Focus Spectrograph (PFS) is a fiber fed multi-object spectrometer for the Subaru Telescope that will conduct a variety of targeted surveys for studies of dark energy, galaxy evolution, and galactic archaeology. The key to the instrument is a high density array of fiber positioners placed at the prime focus of the Subaru Telescope. The system, nicknamed "Cobra", will be capable of rapidly reconfiguring the array of 2394 optical fibers to the image positions of astronomical targets in the focal plane with high accuracy. The system uses 2394 individual "SCARA robot" mechanisms that are 7.7mm in diameter and use 2 piezo-electric rotary motors to individually position each of the optical fibers within its patrol region. Testing demonstrates that the Cobra positioner can be moved to within 5 micrometers of an astronomical target in 6 move iterations with a success rate of 95%. The Cobra system is a key aspect of PFS that will enable its unprecedented combination of high-multiplex factor and observing efficiency on the Subaru telescope. The requirements, design, and prototyping efforts for the fiber positioner system for the PFS are described here as are the plans for modular construction, assembly, integration, functional testing, and performance validation.

Temporal signatures of the Cherenkov light induced by extensive air showers of cosmic rays detected with the Yakutsk array

NASA Astrophysics Data System (ADS)

Ivanov, A. A.; Timofeev, L. V.

2016-05-01

We analyze temporal characteristics of signals from the wide field-of-view (WFOV) Cherenkov telescope (CT) detecting extensive air showers (EAS) of cosmic rays (CRs) in coincidence with surface detectors of the Yakutsk array. Our aim is to reveal causal relationships between measured characteristics and physical properties of EAS.

Photodetectors on Coronagraph Mask for Pointing Control

NASA Technical Reports Server (NTRS)

Balasubramanian, Kunjithapatham

2007-01-01

It has been proposed to install a symmetrical array of photodetectors about the center of the mask of a coronagraph of the type used to search for planets orbiting remote stars. The purpose of this installation is to utilize the light from a star under observation as a guide in pointing the telescope. Simple arithmetic processing of the outputs of the photodetectors would provide indications of the lateral position of the center of the mask relative to the center of the image of the star. These indications could serve as pointing-control feedback signals for adjusting the telescope aim to center the image of the star on the mask. The widths of central mask areas available for placement of photodetectors differ among coronagraph designs, typically ranging upward from about 100 m. Arrays of photodetectors can readily be placed within areas in this size range. The number of detectors in an array could be as small as 4 or as large as 64. The upper limit on the number of detectors would be determined according to the extent of the occulting pattern and the number of functionalities, in addition to pointing control, to be served by the array.

CryoPAF4: a cryogenic phased array feed design

NASA Astrophysics Data System (ADS)

Locke, Lisa; Garcia, Dominic; Halman, Mark; Henke, Doug; Hovey, Gary; Jiang, Nianhua; Knee, Lewis; Lacy, Gordon; Loop, David; Rupen, Michael; Veidt, Bruce; Wierzbicki, Ramunas

2016-07-01

Phased array feed (PAF) receivers used on radio astronomy telescopes offer the promise of increased fields of view while maintaining the superlative performance attained with traditional single pixel feeds (SPFs). However, the much higher noise temperatures of room temperature PAFs compared to cryogenically-cooled SPFs have prevented their general adoption. Here we describe a conceptual design for a cryogenically cooled 2.8 - 5.18 GHz dual linear polarization PAF with estimated receiver temperature of 11 K. The cryogenic PAF receiver will comprise a 140 element Vivaldi antenna array and low-noise amplifiers housed in a 480 mm diameter cylindrical dewar covered with a RF transparent radome. A broadband two-section coaxial feed is integrated within each metal antenna element to withstand the cryogenic environment and to provide a 50 ohm impedance for connection to the rest of the receiver. The planned digital beamformer performs digitization, frequency band selection, beam forming and array covariance matrix calibration. Coupling to a 15 m offset Gregorian dual-reflector telescope, cryoPAF4 can expect to form 18 overlapping beams increasing the field of view by a factor of 8x compared to a single pixel receiver of equal system temperature.

Elastic Distribution of Microshutters, Measurements Obtainable on James Web Space Telescope

NASA Technical Reports Server (NTRS)

Kletetschka, Gunther; King, Todd; Mikula, Vilem

2008-01-01

Spectrographic astronomy measurements in the near-infrared region will be done by functional two-dimensional microshutter arrays that are being fabricated at the NASA Goddard Space Flight Center for the James Webb Space Telescope (JWST). These micro-shutter arrays will represent the first mission-critical MEMS devices to be flown in space. JWST will use microshutter arrays to select focal plane object. 2-D programmable aperture masks of more than 200,000 elements select such space object. The use of silicon wafer material promises high efficiency and high contrast. Microshutter operation temperature is around 35K. Microshutter arrays are fabricated as close-packed silicon nitride membranes with a unit cell size of 105 x 204 micrometers. A layer of magnetic material is deposited onto each shutter. Individual shutters are equipped with a torsion flexure. Reactive ion etching (RIE) releases the shutters so they can open up to 90 degrees using the torsion flexure. Shutter rotation is initiated into a silicon support structure via an external magnetic field. Two electrically independent aluminum electrodes are deposited, one onto each shutter and another onto the support structure side-wall, permitting electrostatic latching and 2-D addressing to hold specific shutters open via external electronics.

Loads Produced During the Ingression and Egression of the Portable Foot Restraint on the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Ramsey, Susan; Rajulu, Sudhakar

2000-01-01

The Hubble Space Telescope (HST) was deployed from the Space Shuttle Discovery on April 25, 1990. It is capable of performing observations in the visible, near-ultraviolet, and near-infrared (1150 A to 1 mm). The HST weighs 12 tons, and collects light with an 8-ft-diameter mirror. The attitude control and maneuvering is performed by four of six gyroscopes, or reaction wheels. The HST contains fine guidance sensors that lock onto guide stars to reduce the spacecraft drift and increase the pointing accuracy. The HST was designed to last 15 years, with crewed service missions approximately every three years. The first service mission, STS-61, took place in 1993. The second service mission took place in 1997. In 1999, the STS-103 crew performed the third service mission to the HST. This mission's purpose was to replace the right sensor units and make improvements on the fine guidance sensors. To perform these tasks on the HST, the STS-103 crewmembers used a portable foot restraint to anchor themselves to the HST in the zero-gravity environment. The solar arrays currently used on the telescope are second-generation, and therefore susceptible to loads placed on the telescope. The crew and Mission Operations Directorate worried about the damage that the crew could possibly cause during ingress and egress of the PFR and by transferring loads to the solar arrays. The purpose of this study is to inform the crewmembers of the loads they are imparting on the HST, and train them to decrease these loads to a safer level. Minimizing these loads will significantly decrease the chance of crewmembers causing damage to the solar arrays while repairing the HST.

Large Format Si:As IBC Array Performance for NGST and Future IR Space Telescope Applications

NASA Technical Reports Server (NTRS)

Ennico, Kimberly; Johnson, Roy; Love, Peter; Lum, Nancy; McKelvey, Mark; McCreight, Craig; McMurray, Robert, Jr.; DeVincenzi, D. (Technical Monitor)

2002-01-01

A mid-IR (5-30micrometer) instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. A space platform's greatly reduced thermal backgrounds (compared to airborne or ground-based platforms), allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. The previous generation's largest, in sensitive IR detectors at these wavelengths are 256x256 pixel Si:As Impurity Band Conduction (IBC) devices built by Raytheon Infrared Operations (RIO) for the Space Infrared Telescope Facility/Infrared Array Camera (SIRTF)/(IRAC) instrument. RIO has successfully enhanced these devices, increasing the pixel count by a factor of 16 while matching or exceeding SIRTF/IRAC device performance. NASA-ARC in collaboration with RIO has tested the first high performance large format (1024x 1024) Si:As IBC arrays for low background applications, such as for the middle instrument on Next Generation Space Telescope (NGST) and future IR Explorer missions. These hybrid devices consist of radiation hard SIRTF/IRAC-type Si:As IBC material mated to a readout multiplexer that has been specially processed for operation at low cryogenic temperatures (below 10K), yielding high device sensitivity over a wavelength range of 5-28 micrometers. We present laboratory testing results from these benchmark, devices. Continued development in this technology is essential for conducting large-area surveys of the local and early universe through observation and for complementing future missions such as NGST, Terrestrial Planet Finder (TPF), and Focal Plane Instruments and Requirement Science Team (FIRST).

Millimetron and Earth-Space VLBI

NASA Astrophysics Data System (ADS)

Likhachev, S.

2014-01-01

The main scientific goal of the Millimetron mission operating in Space VLBI (SVLBI) mode will be the exploration of compact radio sources with extremely high angular resolution (better than one microsecond of arc). The space-ground interferometer Millimetron has an orbit around L2 point of the Earth - Sun system and allows operating with baselines up to a hundred Earth diameters. SVLBI observations will be accomplished by space and ground-based radio telescopes simultaneously. At the space telescope the received baseband signal is digitized and then transferred to the onboard memory storage (up to 100TB). The scientific and service data transfer to the ground tracking station is performed by means of both synchronization and communication radio links (1 GBps). Then the array of the scientific data is processed at the correlation center. Due to the (u,v) - plane coverage requirements for SVLBI imaging, it is necessary to propose observations at two different frequencies and two circular polarizations simultaneously with frequency switching. The total recording bandwidth (2x2x4 GHz) defines of the on-board memory size. The ground based support of the Millimetron mission in the VLBI-mode could be Atacama Large Millimeter Array (ALMA), Pico Valletta (Spain), Plateau de Bure interferometer (France), SMT telescope in the US (Arizona), LMT antenna (Mexico), SMA array, (Mauna Kea, USA), as well as the Green Bank and Effelsberg 100 m telescopes (for 22 GHz observations). We will present simulation results for Millimetron-ALMA interferometer. The sensitivity estimate of the space-ground interferometer will be compared to the requirements of the scientific goals of the mission. The possibility of multi-frequency synthesis (MFS) to obtain high quality images will also be considered.

A user interface framework for the Square Kilometre Array: concepts and responsibilities

NASA Astrophysics Data System (ADS)

Marassi, Alessandro; Brajnik, Giorgio; Nicol, Mark; Alberti, Valentina; Le Roux, Gerhard

2016-07-01

The Square Kilometre Array (SKA) project is responsible for developing the SKA Observatory, the world's largest radio telescope, with eventually over a square kilometre of collecting area and including a general headquarters as well as two radio telescopes: SKA1-Mid in South Africa and SKA1-Low in Australia. The SKA project consists of a number of subsystems (elements) among which the Telescope Manager (TM) is the one involved in controlling and monitoring the SKA telescopes. The TM element has three primary responsibilities: management of astronomical observations, management of telescope hardware and software subsystems, management of data to support system operations and all stakeholders (operators, maintainers, engineers and science users) in achieving operational, maintenance and engineering goals. Operators, maintainers, engineers and science users will interact with TM via appropriate user interfaces (UI). The TM UI framework envisaged is a complete set of general technical solutions (components, technologies and design information) for implementing a generic computing system (UI platform). Such a system will enable UI components to be instantiated to allow for human interaction via screens, keyboards, mouse and to implement the necessary logic for acquiring or deriving the information needed for interaction. It will provide libraries and specific Application Programming Interfaces (APIs) to implement operator and engineer interactive interfaces. This paper will provide a status update of the TM UI framework, UI platform and UI components design effort, including the technology choices, and discuss key challenges in the TM UI architecture, as well as our approaches to addressing them.

Supernova and optical transient observations using the three wide-field telescope array of the KMTNet

NASA Astrophysics Data System (ADS)

Moon, Dae-Sik; Kim, Sang Chul; Lee, Jae-Joon; Pak, Mina; Park, Hong Soo; He, Matthias Y.; Antoniadis, John; Ni, Yuan Qi; Lee, Chung-Uk; Kim, Seung-Lee; Park, Byeong-Gon; Kim, Dong-Jin; Cha, Sang-Mok; Lee, Yongseok; Gonzalez, Santiago

2016-08-01

The Korea Microlensing Telescope Network (KMTNet) is a network of three new 1.6-m, wide-field telescopes spread over three different sites in Chile, South Africa and Australia. Each telescope is equipped with a four square degree wide-field CCD camera, making the KMTNet an ideal facility for discovering and monitoring early supernovae and other rapidly evolving optical transients by providing 24-hour continuous sky coverage. We describe our inaugurating program of observing supernovae and optical transients using about 20% of the KMTNet time in 2015-2019. Our early results include detection of infant supernovae, novae and peculiar transients as well as numerous variable stars and low surface brightness objects such as dwarf galaxies.

Cosmic non-TEM radiation and synthetic feed array sensor system in ASIC mixed signal technology

NASA Astrophysics Data System (ADS)

Centureli, F.; Scotti, G.; Tommasino, P.; Trifiletti, A.; Romano, F.; Cimmino, R.; Saitto, A.

2014-08-01

The paper deals with the opportunity to introduce "Not strictly TEM waves" Synthetic detection Method (NTSM), consisting in a Three Axis Digital Beam Processing (3ADBP), to enhance the performances of radio telescope and sensor systems. Current Radio Telescopes generally use the classic 3D "TEM waves" approximation Detection Method, which consists in a linear tomography process (Single or Dual axis beam forming processing) neglecting the small z component. The Synthetic FEED ARRAY three axis Sensor SYSTEM is an innovative technique using a synthetic detection of the generic "NOT strictly TEM Waves radiation coming from the Cosmo, which processes longitudinal component of Angular Momentum too. Than the simultaneous extraction from radiation of both the linear and quadratic information component, may reduce the complexity to reconstruct the Early Universe in the different requested scales. This next order approximation detection of the observed cosmologic processes, may improve the efficacy of the statistical numerical model used to elaborate the same information acquired. The present work focuses on detection of such waves at carrier frequencies in the bands ranging from LF to MMW. The work shows in further detail the new generation of on line programmable and reconfigurable Mixed Signal ASIC technology that made possible the innovative Synthetic Sensor. Furthermore the paper shows the ability of such technique to increase the Radio Telescope Array Antenna performances.

The Status and Recent Results of the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Yamazaki, Katsuya

The Telescope Array (TA) is a cosmic ray observatory of the largest aperture in the northern hemisphere, located in a desert in the western part of Utah, U.S.A., to explore the origin of ultrahigh energy cosmic rays, photons, and neutrinos. The TA employs two types of detectors to observe air showers generated by cosmic rays in the atmosphere: the first is a "surface detector (SD)" of scintillation counters to measure shower particles on the ground, and the second is a "fluorescence detector (FD)" of telescopes installed in three stations to observe fluorescence light, caused by air shower particles, from the atmosphere above the SD array. The TA detectors have been in routine operation since May 2008. We measured the energy spectrum of cosmic rays with energy greater than 1018 eV from our first 4-year data. We found a clear suppression of comic ray intensity above 5 × 1019 eV. This feature is consistent with a theoretical prediction that cosmic rays lose energies due to interaction with cosmic microwave background photons during propagation in the intergalactic space. In this talk, We will present the status of the TA experiment and the recent results, including the energy spectrum, study of the primary mass composition, and searches for anisotropies in the arrival directions. We also briefly describe plans for further extensions.

1100789

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

1100788

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

1100792

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

1100790

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

1100793

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

1100787

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

1100791

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

1100794

NASA Image and Video Library

2011-06-13

BALL AEROSPACE ENGINEER DAVE CHANEY, (L), AND MARSHALL ENGINEER HARLAN HAIGHT, (R), GUIDE ARRAY OF SIX GOLD-PLATED JAMES WEBB SPACE TELESCOPE MIRRORS AFTER FINAL ACCEPTANCE TESTING AT MARSHALL'S X-RAY AND CRYOGENIC FACILITY

Software use cases to elicit the software requirements analysis within the ASTRI project

NASA Astrophysics Data System (ADS)

Conforti, Vito; Antolini, Elisa; Bonnoli, Giacomo; Bruno, Pietro; Bulgarelli, Andrea; Capalbi, Milvia; Fioretti, Valentina; Fugazza, Dino; Gardiol, Daniele; Grillo, Alessandro; Leto, Giuseppe; Lombardi, Saverio; Lucarelli, Fabrizio; Maccarone, Maria Concetta; Malaguti, Giuseppe; Pareschi, Giovanni; Russo, Federico; Sangiorgi, Pierluca; Schwarz, Joseph; Scuderi, Salvatore; Tanci, Claudio; Tosti, Gino; Trifoglio, Massimo; Vercellone, Stefano; Zanmar Sanchez, Ricardo

2016-07-01

The Italian National Institute for Astrophysics (INAF) is leading the Astrofisica con Specchi a Tecnologia Replicante Italiana (ASTRI) project whose main purpose is the realization of small size telescopes (SST) for the Cherenkov Telescope Array (CTA). The first goal of the ASTRI project has been the development and operation of an innovative end-to-end telescope prototype using a dual-mirror optical configuration (SST-2M) equipped with a camera based on silicon photo-multipliers and very fast read-out electronics. The ASTRI SST-2M prototype has been installed in Italy at the INAF "M.G. Fracastoro" Astronomical Station located at Serra La Nave, on Mount Etna, Sicily. This prototype will be used to test several mechanical, optical, control hardware and software solutions which will be used in the ASTRI mini-array, comprising nine telescopes proposed to be placed at the CTA southern site. The ASTRI mini-array is a collaborative and international effort led by INAF and carried out by Italy, Brazil and South-Africa. We present here the use cases, through UML (Unified Modeling Language) diagrams and text details, that describe the functional requirements of the software that will manage the ASTRI SST-2M prototype, and the lessons learned thanks to these activities. We intend to adopt the same approach for the Mini Array Software System that will manage the ASTRI miniarray operations. Use cases are of importance for the whole software life cycle; in particular they provide valuable support to the validation and verification activities. Following the iterative development approach, which breaks down the software development into smaller chunks, we have analysed the requirements, developed, and then tested the code in repeated cycles. The use case technique allowed us to formalize the problem through user stories that describe how the user procedurally interacts with the software system. Through the use cases we improved the communication among team members, fostered common agreement about system requirements, defined the normal and alternative course of events, understood better the business process, and defined the system test to ensure that the delivered software works properly. We present a summary of the ASTRI SST-2M prototype use cases, and how the lessons learned can be exploited for the ASTRI mini-array proposed for the CTA Observatory.

The software architecture to control the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Oya, I.; Füßling, M.; Antonino, P. O.; Conforti, V.; Hagge, L.; Melkumyan, D.; Morgenstern, A.; Tosti, G.; Schwanke, U.; Schwarz, J.; Wegner, P.; Colomé, J.; Lyard, E.

2016-07-01

The Cherenkov Telescope Array (CTA) project is an initiative to build two large arrays of Cherenkov gamma- ray telescopes. CTA will be deployed as two installations, one in the northern and the other in the southern hemisphere, containing dozens of telescopes of different sizes. CTA is a big step forward in the field of ground- based gamma-ray astronomy, not only because of the expected scientific return, but also due to the order-of- magnitude larger scale of the instrument to be controlled. The performance requirements associated with such a large and distributed astronomical installation require a thoughtful analysis to determine the best software solutions. The array control and data acquisition (ACTL) work-package within the CTA initiative will deliver the software to control and acquire the data from the CTA instrumentation. In this contribution we present the current status of the formal ACTL system decomposition into software building blocks and the relationships among them. The system is modelled via the Systems Modelling Language (SysML) formalism. To cope with the complexity of the system, this architecture model is sub-divided into different perspectives. The relationships with the stakeholders and external systems are used to create the first perspective, the context of the ACTL software system. Use cases are employed to describe the interaction of those external elements with the ACTL system and are traced to a hierarchy of functionalities (abstract system functions) describing the internal structure of the ACTL system. These functions are then traced to fully specified logical elements (software components), the deployment of which as technical elements, is also described. This modelling approach allows us to decompose the ACTL software in elements to be created and the ow of information within the system, providing us with a clear way to identify sub-system interdependencies. This architectural approach allows us to build the ACTL system model and trace requirements to deliverables (source code, documentation, etc.), and permits the implementation of a flexible use-case driven software development approach thanks to the traceability from use cases to the logical software elements. The Alma Common Software (ACS) container/component framework, used for the control of the Atacama Large Millimeter/submillimeter Array (ALMA) is the basis for the ACTL software and as such it is considered as an integral part of the software architecture.

A Generic and Efficient E-field Parallel Imaging Correlator for Next-Generation Radio Telescopes

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan; Beardsley, Adam P.; Bowman, Judd D.; Morales, Miguel F.

2017-05-01

Modern radio telescopes are favouring densely packed array layouts with large numbers of antennas (NA ≳ 1000). Since the complexity of traditional correlators scales as O(N_A^2), there will be a steep cost for realizing the full imaging potential of these powerful instruments. Through our generic and efficient E-field Parallel Imaging Correlator (epic), we present the first software demonstration of a generalized direct imaging algorithm, namely the Modular Optimal Frequency Fourier imager. Not only does it bring down the cost for dense layouts to O(N_A log _2N_A) but can also image from irregular layouts and heterogeneous arrays of antennas. epic is highly modular, parallelizable, implemented in object-oriented python, and publicly available. We have verified the images produced to be equivalent to those from traditional techniques to within a precision set by gridding coarseness. We have also validated our implementation on data observed with the Long Wavelength Array (LWA1). We provide a detailed framework for imaging with heterogeneous arrays and show that epic robustly estimates the input sky model for such arrays. Antenna layouts with dense filling factors consisting of a large number of antennas such as LWA, the Square Kilometre Array, Hydrogen Epoch of Reionization Array, and Canadian Hydrogen Intensity Mapping Experiment will gain significant computational advantage by deploying an optimized version of epic. The algorithm is a strong candidate for instruments targeting transient searches of fast radio bursts as well as planetary and exoplanetary phenomena due to the availability of high-speed calibrated time-domain images and low output bandwidth relative to visibility-based systems.

Assembly, characterization, and operation of large-scale TES detector arrays for ACTPol

NASA Astrophysics Data System (ADS)

Pappas, Christine Goodwin

2016-01-01

The Polarization-sensitive Receiver for the Atacama Cosmology Telescope (ACTPol) is designed to measure the Cosmic Microwave Background (CMB) temperature and polarization anisotropies on small angular scales. Measurements of the CMB temperature and polarization anisotropies have produced arguably the most important cosmological data to date, establishing the LambdaCDM model and providing the best constraints on most of its parameters. To detect the very small fluctuations in the CMB signal across the sky, ACTPol uses feedhorn-coupled Transition-Edge Sensor (TES) detectors. A TES is a superconducting thin film operated in the transition region between the superconducting and normal states, where it functions as a highly sensitive resistive thermometer. In this thesis, aspects of the assembly, characterization, and in-field operation of the ACTPol TES detector arrays are discussed. First, a novel microfabrication process for producing high-density superconducting aluminum/polyimide flexible circuitry (flex) designed to connect large-scale detector arrays to the first stage of readout is presented. The flex is used in parts of the third ACTPol array and is currently being produced for use in the AdvACT detector arrays, which will begin to replace the ACTPol arrays in 2016. Next, we describe methods and results for the in-lab and on-telescope characterization of the detectors in the third ACTPol array. Finally, we describe the ACTPol TES R(T,I) transition shapes and how they affect the detector calibration and operation. Methods for measuring the exact detector calibration and re-biasing functions, taking into account the R(T,I) transition shape, are presented.

VizieR Online Data Catalog: Photometry of the transient event iPTF16fnl (Blagorodnova+, 2017)

NASA Astrophysics Data System (ADS)

Blagorodnova, N.; Gezari, S.; Hung, T.; Kulkarni, S. R.; Cenko, S. B.; Pasham, D. R.; Yan, L.; Arcavi, I.; Ben-Ami, S.; Bue, B. D.; Cantwell, T.; Cao, Y.; Castro-Tirado, A. J.; Fender, R.; Fremling, C.; Gal-Yam, A.; Ho, A. Y. Q.; Horesh, A.; Hosseinzadeh, G.; Kasliwal, M. M.; Kong, A. K. H.; Laher, R. R.; Leloudas, G.; Lunnan, R.; Masci, F. J.; Mooley, K.; Neill, J. D.; Nugent, P.; Powell, M.; Valeev, A. F.; Vreeswijk, P. M.; Walters, R.; Wozniak, P.

2018-03-01

On the night after discovery (2016 August 29th), we observed the source with the FLOYDS spectrograph on the Las Cumbres Observatory (LCO) 2m telescope and the Spectral Energy Distribution Machine (SEDM) on the Palomar 60 inch (P60) telescope. The SEDM is a ultra-low resolution (R~100) integral-field-unit (IFU) spectrograph. Following spectroscopic identification of iPTF16fnl as a tidal disruption event (TDE) candidate, the source was monitored at Palomar and by the Ultraviolet and Optical Telescope (UVOT) on board the Swift observatory. The UVOT observations were taken in UVW2, UVM2, UVW1, U, B, and V. At Palomar, photometry in the g and Mould-R bands were obtained with the iPTF mosaic wide-field camera on the Palomar 48-inch telescope (P48). Table 3 reports the measured Swift aperture photometry magnitudes and the difference-imaging photometry for the Palomar data spanning 2016 Aug to 2016 Dec. Radio follow-up observations of iPTF16fnl were taken with the Jansky Very Large Array (VLA; PI A. Horesh), the Arcminute Microkelvin Imager (AMI; PI K. Mooley) and the James Clerk Maxwell Telescope and the Submillimetre Common-User Bolometer Array 2 (JCMT/SCUBA-2; PI A. K. H. Kong). We also observed the location of iPTF16fnl with the X-Ray Telescope (XRT) on board the Swift satellite beginning at 19:32 UT on 30 August 2016. Regular monitoring of the field in photon counting mode continued over the course of the next four months (PIs T. Holoien and B. Cenko). (1 data file).

A Census of Southern Pulsars at 185 MHz

NASA Astrophysics Data System (ADS)

Xue, Mengyao; Bhat, N. D. R.; Tremblay, S. E.; Ord, S. M.; Sobey, C.; Swainston, N. A.; Kaplan, D. L.; Johnston, Simon; Meyers, B. W.; McSweeney, S. J.

2017-12-01

The Murchison Widefield Array, and its recently developed Voltage Capture System, facilitates extending the low-frequency range of pulsar observations at high-time and -frequency resolution in the Southern Hemisphere, providing further information about pulsars and the ISM. We present the results of an initial time-resolved census of known pulsars using the Murchison Widefield Array. To significantly reduce the processing load, we incoherently sum the detected powers from the 128 Murchison Widefield Array tiles, which yields 10% of the attainable sensitivity of the coherent sum. This preserves the large field-of-view ( 450 deg2 at 185 MHz), allowing multiple pulsars to be observed simultaneously. We developed a WIde-field Pulsar Pipeline that processes the data from each observation and automatically folds every known pulsar located within the beam. We have detected 50 pulsars to date, 6 of which are millisecond pulsars. This is consistent with our expectation, given the telescope sensitivity and the sky coverage of the processed data ( 17 000 deg2). For 10 pulsars, we present the lowest frequency detections published. For a subset of the pulsars, we present multi-frequency pulse profiles by combining our data with published profiles from other telescopes. Since the Murchison Widefield Array is a low-frequency precursor to the Square Kilometre Array, we use our census results to forecast that a survey using the low-frequency component of the Square Kilometre Array Phase 1 can potentially detect around 9 400 pulsars.

Composition Measurements via Depth of Airshower Maximum at the Telescope Array

NASA Astrophysics Data System (ADS)

Hanlon, W.; Belz, J.; Ikeda, D.; Lundquist, J. P.; Sokolsky, P.; Stroman, T.; Tsunesada, Y.

Telescope Array (TA) was designed to answer important questions about the UHECR flux with energies above 1017 eV such as spectrum, arrival direction, and mass composition. Because the UHECR flux is rapidly falling in this energy region, TA's large exposure makes it one of the few experiments in the world that can adequately explore these issues. Composition is particularly difficult to measure because mass can not be measured directly due to the low flux. TA's multiple methods of observing UHECR induced air showers will be explained, as well as how composition can be measured by these methods. Good agreement among the different measurement techniques is found leading to greater confidence in measuring UHECR mass composition and a way to test and understand TA systematic uncertainties.

Commissioning of the FTS-2 Data Reduction Pipeline

NASA Astrophysics Data System (ADS)

Sherwood, M.; Naylor, D.; Gom, B.; Bell, G.; Friberg, P.; Bintley, D.

2015-09-01

FTS-2 is the intermediate resolution Fourier Transform Spectrometer coupled to the SCUBA-2 facility bolometer camera at the James Clerk Maxwell Telescope in Hawaii. Although in principle FTS instruments have the advantage of relatively simple optics compared to other spectrometers, they require more sophisticated data processing to compute spectra from the recorded interferogram signal. In the case of FTS-2, the complicated optical design required to interface with the existing telescope optics introduces performance compromises that complicate spectral and spatial calibration, and the response of the SCUBA-2 arrays introduce interferogram distortions that are a challenge for data reduction algorithms. We present an overview of the pipeline and discuss new algorithms that have been written to correct the noise introduced by unexpected behavior of the SCUBA-2 arrays.

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

NASA Astrophysics Data System (ADS)

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.

Battery-powered thin film deposition process for coating telescope mirrors in space

NASA Astrophysics Data System (ADS)

Sheikh, David A.

2016-07-01

Aluminum films manufactured in the vacuum of space may increase the broadband reflectance response of a space telescope operating in the EUV (50-nm to 115-nm) by eliminating absorbing metal-fluorides and metal-oxides, which significantly reduce aluminum's reflectance below 115-nm. Recent developments in battery technology allow small lithium batteries to rapidly discharge large amounts of energy. It is therefore conceivable to power an array of resistive evaporation filaments in a space environment, using a reasonable mass of batteries and other hardware. This paper presents modeling results for coating thickness as a function of position, for aluminum films made with a hexagonal array of battery powered evaporation sources. The model is based on measured data from a single battery-powered evaporation source.

X-ray/EUV optics for astronomy, microscopy, polarimetry, and projection lithography; Proceedings of the Meeting, San Diego, CA, July 9-13, 1990

NASA Technical Reports Server (NTRS)

Hoover, Richard B. (Editor); Walker, Arthur B. C., Jr. (Editor)

1991-01-01

Topics discussed in this issue include the fabrication of multilayer X-ray/EUV coatings; the design, characterization, and test of multilayer X-ray/EUV coatings; multilayer X-ray/EUV monochromators and imaging microscopes; X-ray/EUV telescopes; the test and calibration performance of X-ray/EUV instruments; XUV/soft X-ray projection lithography; X-ray/EUV space observatories and missions; X-ray/EUV telescopes for solar research; X-ray/EUV polarimetry; X-ray/EUV spectrographs; and X-ray/EUV filters and gratings. Papers are presented on the deposition-controlled uniformity of multilayer mirrors, interfaces in Mo/Si multilayers, the design and analysis of an aspherical multilayer imaging X-ray microscope, recent developments in the production of thin X-ray reflecting foils, and the ultraprecise scanning technology. Consideration is also given to an active sun telescope array, the fabrication and performance at 1.33 nm of a 0.24-micron-period multilayer grating, a cylindrical proportional counter for X-ray polarimetry, and the design and analysis of the reflection grating arrays for the X-Ray Multi-Mirror Mission.

Sensitive observations with the Spacelab 2 infrared telescope

NASA Technical Reports Server (NTRS)

Young, E. T.; Rieke, G. H.; Gautier, T. N.; Hoffmann, W. F.; Low, F. J.; Poteet, W.; Fazio, G. G.; Koch, D.; Traub, W. A.; Urban, E. W.

1983-01-01

The small helium-cooled infrared telescope (Spacelab IRT) is a multiband instrument capable of highly sensitive observations from space. The experiment consists of a cryogenically cooled, very well baffled telescope with a ten channel focal plane array. During the Spacelab 2 flight of the Space Shuttle, this instrument will make observations between 5 and 120 micron wavelength that will be background limited by the expected zodiacal emission. Design considerations necessitated by this level of performance are discussed in this paper. In particular, the operation of a very sensitive focal plane array in the space environment is described. The Spacelab IRT will be used to map the extended, low-surface brightness celestial emission. During the seven day length of the mission better than 70 percent sky coverage is expected. The instrument will also be used to measure the infrared contamination environment of the Space Shuttle. This information will be important in the development of the next generation of infrared astronomical instruments. The performance of the Spacelab IRT, in particular its sensitivity to the contamination environment is detailed.

The Beaming Structures of Jupiter’s Decametric Common S-bursts Observed from the LWA1, NDA, and URAN2 Radio Telescopes

NASA Astrophysics Data System (ADS)

Imai, Masafumi; Lecacheux, Alain; Clarke, Tracy E.; Higgins, Charles A.; Panchenko, Mykhaylo; Dowell, Jayce; Imai, Kazumasa; Brazhenko, Anatolii I.; Frantsuzenko, Anatolii V.; Konovalenko, Alexandr A.

2016-08-01

On 2015 February 21, simultaneous observations of Jupiter's decametric radio emission between 10 and 33 MHz were carried out using three powerful low-frequency radio telescopes: the Long Wavelength Array Station One in the USA, the Nançay Decameter Array in France, and the URAN2 telescope in Ukraine. We measured the lag times of short-bursts (S-bursts) for 105 minutes of data over effective baselines of up to 8460 km by using cross-correlation analysis of the spectrograms from each instrument. Of particular interest is the measurement of the beaming thickness of S-bursts, testing if either flashlight- or beacon-like beaming is emanating from Jupiter. We find that the lag times for all pairs drift slightly as time elapses, in agreement with expectations from the flashlight-like beaming model. This leads to a new constraint of the minimum beaming thickness of 2.″66. Also, we find that most of the analyzed data abound with S-bursts, whose occurrence probability peaks at 17-18 MHz.

Launch Will Create a Radio Telescope Larger than Earth

NASA Astrophysics Data System (ADS)

NASA and the National Radio Astronomy Observatory are joining with an international consortium of space agencies to support the launch of a Japanese satellite next week that will create the largest astronomical "instrument" ever built -- a radio telescope more than two-and-a-half times the diameter of the Earth that will give astronomers their sharpest view yet of the universe. The launch of the Very Long Baseline Interferometry (VLBI) Space Observatory Program (VSOP) satellite by Japan's Institute of Space and Astronautical Science (ISAS) is scheduled for Feb. 10 at 11:50 p.m. EST (1:50 p.m. Feb. 11, Japan time.) The satellite is part of an international collaboration led by ISAS and backed by Japan's National Astronomical Observatory; NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA; the National Science Foundation's National Radio Astronomy Observatory (NRAO), Socorro, NM; the Canadian Space Agency; the Australia Telescope National Facility; the European VLBI Network and the Joint Institute for Very Long Baseline Interferometry in Europe. Very long baseline interferometry is a technique used by radio astronomers to electronically link widely separated radio telescopes together so they work as if they were a single instrument with extraordinarily sharp "vision," or resolving power. The wider the distance between telescopes, the greater the resolving power. By taking this technique into space for the first time, astronomers will approximately triple the resolving power previously available with only ground-based telescopes. The satellite system will have resolving power almost 1,000 times greater than the Hubble Space Telescope at optical wavelengths. The satellite's resolving power is equivalent to being able to see a grain of rice in Tokyo from Los Angeles. "Using space VLBI, we can probe the cores of quasars and active galaxies, believed to be powered by super massive black holes," said Dr. Robert Preston, project scientist for the U.S. Space Very Long Baseline Interferometry project at JPL. "Observations of cosmic masers -- naturally-occurring microwave radio amplifiers -- will tell us new things about the process of star formation and activity in the heart of other galaxies." "By the 1980s, radio astronomers were observing the universe with assemblages of radio telescopes whose resolving power was limited only by the size of the Earth. Now, through a magnificent international effort, we will be able to break this barrier and see fine details of celestial objects that are beyond the reach of a purely ground-based telescope array. We anticipate a rich harvest of new scientific knowledge from VSOP," said Dr. Paul Vanden Bout, Director of NRAO. In the first weeks after launch, scientists and engineers will "test the deployment of the reflecting mesh telescope in orbit, the wide-band data link from the satellite to the ground, the performance of the low noise amplifiers in orbit, and the high-precision orbit determination and attitude control necessary for VLBI observations with an orbiting telescope," according to Dr. Joel Smith, manager of the U.S. Space VLBI project at JPL. Scientific observations are expected to begin in May. The 26-foot diameter orbiting radio telescope will observe celestial radio sources in concert with a number of the world's ground-based radio telescopes. The 1,830-pound satellite will be launched from ISAS' Kagoshima Space Center, at the southern tip of Kyushu, one of Japan's main islands, and will be the first launch with ISAS' new M-5 series rocket. The satellite will go into an elliptical orbit, varying between 620 to 12,400 miles above the Earth's surface. This orbit provides a wide range of distances between the satellite and ground-based telescopes, which is important for producing a high-quality image of the radio source being observed. One orbit of the Earth will take about six hours. The satellite's observations will concentrate on some of the most distant and intriguing objects in the universe, where the extremely sharp radio "vision" of the new system can provide much-needed information about a number of astronomical mysteries. For years, astronomers have known that powerful "engines" in the hearts of quasars and many galaxies are pouring out tremendous amounts of energy. They suspect that supermassive black holes, with gravitational fields so strong that not even light can escape them, lie in the centers of these "engines." The mechanism at work in the centers of quasars and active galaxies, however, remains a mystery. Ground-based radio telescopes, notably NRAO's Very Long Baseline Array (VLBA), have revealed fascinating new details in recent years, and VSOP is expected to add a wealth of new information on these objects, millions or billions of light-years distant from Earth. Many of these same objects act as super-powerful particle accelerators to eject "jets" of subatomic particles at nearly the speed of light. Scientists plan to use VSOP to monitor the changes and motions in these jets to learn more about how they originate and interact with their surroundings. The satellite also will aim at regions in the sky where giant collections of water and other molecules act as natural amplifiers of radio emission much as lasers amplify light. These regions, called cosmic masers, are found in areas where new stars are forming and near the centers of galaxies. Observations can provide the detail needed to measure motions of individual maser "spots" within these regions, and provide exciting new information about the star-forming regions and the galaxies where the masers reside. In addition, high-resolution studies of cosmic masers can allow astronomers to calculate distances to them with unprecedented accuracy, and thus help resolve continuing questions about the size and age of the universe. The project is a major international undertaking, with about 40 radio telescopes from more than 15 countries having committed time to co-observe with the satellite. This includes the National Science Foundation's Very Long Baseline Array (VLBA), an array of 10 telescopes spanning the United States from Hawaii to Saint Croix; NASA's Deep Space Network (DSN) sites in California, Spain, and Australia; the European VLBI Network, more than a dozen telescopes ranging from the United Kingdom to China; a Southern Hemisphere array of telescopes stretching from eastern Australia to South Africa; and Japan's network of domestic radio telescopes. In the United States, NASA is funding critical roles in the VSOP mission at both JPL and NRAO. JPL has built an array of three new tracking stations at its DSN sites in Goldstone, CA; Madrid, Spain; and near Canberra, Australia. A large existing tracking station at each of these sites has also been converted to an extremely sensitive radio telescope for simultaneous observations with the satellite. JPL also is providing precision orbit determination, scientific and operational planning support to the Japanese, and advice to U.S. astronomers who wish to observe with the satellite. NRAO is building a new tracking station at Green Bank, WV; contributing observing time on the VLBA array of telescopes; modifying existing data analysis hardware and software, and aiding astronomers with the analysis of the VSOP data. Much of the observational data will be processed at NRAO's facility in Socorro, NM, using the VLBA Correlator, a special purpose high-performance computer designed to process VLBI data. VSOP is the culmination of many years of planning and work by scientists and engineers around the world. Tests using NASA's Tracking and Data Relay Satellite System (TDRSS) proved the feasibility of space VLBI in 1986. Just last year, those old data were used again to test successfully the data-reduction facilities for VSOP. JPL manages the U.S. Space Very Long Baseline Interferometry project for NASA's Office of Space Science, Washington, DC. The VLBA, headquartered in Socorro, NM, is part of the National Radio Astronomy Observatory, a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Hubble Space Telescope (HST) above OV-103's PLB during STS-31 deployment

NASA Image and Video Library

1990-04-25

The Hubble Space Telescope (HST) is raised above the payload bay (PLB) in low hover position during STS-31 checkout and pre-deployment procedures aboard Discovery, Orbiter Vehicle (OV) 103. Stowed along the HST Support System Module (SSM) are the high gain antenna (HGA) (center) and the two solar arrays (one either side). In the background are the orbital maneuvering system (OMS) pods and the Earth's surface.

The data acquisition system for the ANTARES neutrino telescope

NASA Astrophysics Data System (ADS)

Aguilar, J. A.; Albert, A.; Ameli, F.; Anghinolfi, M.; Anton, G.; Anvar, S.; Aslanides, E.; Aubert, J.-J.; Barbarito, E.; Basa, S.; Battaglieri, M.; Becherini, Y.; Bellotti, R.; Beltramelli, J.; Bertin, V.; Bigi, A.; Billault, M.; Blaes, R.; de Botton, N.; Bouwhuis, M. C.; Bradbury, S. M.; Bruijn, R.; Brunner, J.; Burgio, G. F.; Busto, J.; Cafagna, F.; Caillat, L.; Calzas, A.; Capone, A.; Caponetto, L.; Carmona, E.; Carr, J.; Cartwright, S. L.; Castel, D.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Ceres, A.; Charvis, P.; Chauchot, P.; Chiarusi, T.; Circella, M.; Colnard, C.; Compère, C.; Coniglione, R.; Cottini, N.; Coyle, P.; Cuneo, S.; Cussatlegras, A.-S.; Damy, G.; van Dantzig, R.; de Marzo, C.; Dekeyser, I.; Delagnes, E.; Denans, D.; Deschamps, A.; Dessages-Ardellier, F.; Destelle, J.-J.; Dinkespieler, B.; Distefano, C.; Donzaud, C.; Drogou, J.-F.; Druillole, F.; Durand, D.; Ernenwein, J.-P.; Escoffier, S.; Falchini, E.; Favard, S.; Feinstein, F.; Ferry, S.; Festy, D.; Fiorello, C.; Flaminio, V.; Galeotti, S.; Gallone, J.-M.; Giacomelli, G.; Girard, N.; Gojak, C.; Goret, Ph.; Graf, K.; Hallewell, G.; Harakeh, M. N.; Hartmann, B.; Heijboer, A.; Heine, E.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hoffman, C.; Hogenbirk, J.; Hubbard, J. R.; Jaquet, M.; Jaspers, M.; de Jong, M.; Jouvenot, F.; Kalantar-Nayestanaki, N.; Kappes, A.; Karg, T.; Karkar, S.; Katz, U.; Keller, P.; Kok, H.; Kooijman, P.; Kopper, C.; Korolkova, E. V.; Kouchner, A.; Kretschmer, W.; Kruijer, A.; Kuch, S.; Kudryavstev, V. A.; Lachartre, D.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lamanna, G.; Lamare, P.; Languillat, J. C.; Laschinsky, H.; Le Guen, Y.; Le Provost, H.; Le van Suu, A.; Legou, T.; Lim, G.; Lo Nigro, L.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Lyashuk, V.; Marcelin, M.; Margiotta, A.; Masullo, R.; Mazéas, F.; Mazure, A.; McMillan, J. E.; Megna, R.; Melissas, M.; Migneco, E.; Milovanovic, A.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Niess, V.; Olivetto, C.; Ostasch, R.; Palanque-Delabrouille, N.; Payre, P.; Peek, H.; Petta, C.; Piattelli, P.; Pineau, J.-P.; Poinsignon, J.; Popa, V.; Pradier, T.; Racca, C.; Randazzo, N.; van Randwijk, J.; Real, D.; van Rens, B.; Réthoré, F.; Rewiersma, P.; Riccobene, G.; Rigaud, V.; Ripani, M.; Roca, V.; Roda, C.; Rolin, J. F.; Romita, M.; Rose, H. J.; Rostovtsev, A.; Roux, J.; Ruppi, M.; Russo, G. V.; Salesa, F.; Salomon, K.; Sapienza, P.; Schmitt, F.; Schuller, J.-P.; Shanidze, R.; Sokalski, I.; Spona, T.; Spurio, M.; van der Steenhoven, G.; Stolarczyk, T.; Streeb, K.; Stubert, D.; Sulak, L.; Taiuti, M.; Tamburini, C.; Tao, C.; Terreni, G.; Thompson, L. F.; Valdy, P.; Valente, V.; Vallage, B.; Venekamp, G.; Verlaat, B.; Vernin, P.; de Vita, R.; de Vries, G.; van Wijk, R.; de Witt Huberts, P.; Wobbe, G.; de Wolf, E.; Yao, A.-F.; Zaborov, D.; Zaccone, H.; Zornoza, J. D.; Zúñiga, J.

2007-01-01

The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described.

Medium power amplifiers covering 90 - 130 GHz for telescope local oscillators

NASA Technical Reports Server (NTRS)

Samoska, Lorene A.; Bryerton, Eric; Pukala, David; Peralta, Alejandro; Hu, Ming; Schmitz, Adele

2005-01-01

This paper describes a set of power amplifier (PA) modules containing InP High Electron Mobility Transistor (HEMT) Monolithic Millimeter-wave Integrated Circuit (MMIC) chips. The chips were designed and optimized for local oscillator sources in the 90-130 GHz band for the Atacama Large Millimeter Array telescope. The modules feature 20-45 mW of output power, to date the highest power from solid state HEMT MMIC modules above 110 GHz.

Hubble Space Telescope Deploy, Cuba, Bahamas and Gulf of Mexico

NASA Image and Video Library

1990-04-29

STS031-151-010 (25 April 1990) --- The Hubble Space Telescope (HST), still in the grasp of Discovery's Remote Manipulator System (RMS), is backdropped over Cuba and the Bahama Islands. In this scene, it has yet to have deployment of its solar array panels and its high gain antennae. This scene was captured with a large format Aero Linhof camera used by several previous flight crews to record Earth scenes.

STS-31 pre-deployment checkout of the Hubble Space Telescope (HST) on OV-103

NASA Image and Video Library

1990-04-25

The Hubble Space Telescope (HST), grappled by Discovery's, Orbiter Vehicle (OV) 103's, remote manipulator system (RMS), is oriented in a 90 degree pitch position during STS-31 pre-deployment checkout procedures. The solar array (SA) panel (center) and high gain antennae (HGA) (on either side) are stowed along the Support System Module (SSM) forward shell prior to deployment. The sun highlights HST against the blackness of space.

47 CFR 15.712 - Interference protection requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

....1 10-30 meters 14.4 0.74 (b) TV translator, Low Power TV (including Class A) and Multi-channel Video... Telescope Array 121 28 24 W 40 49 04 N Arecibo Observatory 066 45 11 W 18 20 46 N Green Bank Telescope (GBT... 07 07 W 34 18 04 N Kitt Peak, AZ 111 36 42 W 31 57 22 N Los Alamos, NM 106 14 42 W 35 46 30 N Ft...

MEqTrees Telescope and Radio-sky Simulations and CPU Benchmarking

NASA Astrophysics Data System (ADS)

Shanmugha Sundaram, G. A.

2009-09-01

MEqTrees is a Python-based implementation of the classical Measurement Equation, wherein the various 2×2 Jones matrices are parametrized representations in the spatial and sky domains for any generic radio telescope. Customized simulations of radio-source sky models and corrupt Jones terms are demonstrated based on a policy framework, with performance estimates derived for array configurations, ``dirty''-map residuals and processing power requirements for such computations on conventional platforms.

Using the Very Large Array (VLA) and other radio telescopes to perform a parasitic Search for Extraterrestrial Intelligence (SETI)

NASA Technical Reports Server (NTRS)

Tarter, J.

1985-01-01

This paper describes several attempts to utilize various radio telescopes in a manner that we term "parasitic," that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories. In the extreme case, only recorded astronomical data are accessed off-line, after the fact, without any burden on the observatory at all.

Using the Very Large Array (VLA) and other radio telescopes to perform a parasitic search for extraterrestrial intelligence (SETI)

NASA Technical Reports Server (NTRS)

Tarter, J. C.

1984-01-01

This paper describes several attempts to utilize various radio telescopes in a manner that is termed 'parasitic', that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories. In the extreme case, only recorded astronomical data are accessed off-line, after the fact, without any burden on the observatory at all.

Using the Very Large Array (VLA) and other radio telescopes to perform a parasitic Search for Extraterrestrial Intelligence (SETI).

PubMed

Tarter, J

1985-01-01

This paper describes several attempts to utilize various radio telescopes in a manner that we term "parasitic," that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories. In the extreme case, only recorded astronomical data are accessed off-line, after the fact, without any burden on the observatory at all.

The detection of high charge cosmic ray nuclei. [by balloon-borne electronic particle telescope

NASA Technical Reports Server (NTRS)

Scarlett, W. R.; Freier, P. S.; Waddington, C. J.

1975-01-01

A large-area, light-weight electronic particle telescope was flown on a high altitude balloon in the summer of 1974 to study the heavy nuclei in the cosmic radiation. This telescope consisted of a double Cerenkov-double scintillator array composed of four 1.22 m diameter disk radiators mounted in light diffusion boxes, each looked at by multiple photomultipliers. The impact point of each particle on the scintillation radiators was determined by studying the relative signals observed by three equally spaced peripheral photomultipliers and one mounted at the center of the diffusion boxes. This telescope was flown in a configuration having a geometric factor of 0.45 sq m sr and observed some 5 x 10 to the 4 nuclei with Z exceeding 14 in a 11 hr exposure. The response and sensitivity of this telescope are discussed in detail.

History of Hubble Space Telescope (HST)

NASA Image and Video Library

1986-01-01

This photograph shows the Hubble Space Telescope (HST) flight article assembly with multilayer insulation, high gain anterna, and solar arrays in a clean room of the Lockheed Missile and Space Company. The HST is the first of NASA's great observatories and the most complex and sensitive optical telescope ever made. The purpose of the HST is to study the cosmos from a low-Earth orbit by placing the telescope in space, enabling astronomers to collect data that is free of the Earth's atmosphere. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had overall responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company, Sunnyvale, California, produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

Astronomical observatories on the Moon

NASA Astrophysics Data System (ADS)

Swanson, Paul N.; Cutts, James A.

1994-06-01

The Space Exploration Initiative presents an opportunity to construct astronomical telescopes on the Moon using the infrastructure provided by the lunar outpost. Small automatically deployed telescopes can be carried on the survey missions, be deployed on the lunar surface and be operated remotely from the Earth. Possibilities for early, small optical telescopes are a zenith pointed transit telescope, a student telescope, and a 0.5 to 1 meter automatic, fully steerable telescope. After the lunar outpost is established the lunar interferometers will be constructed in an evolutionary fashion. There are three lunar interferometers which have been studied. The most ambitious is the optical interferometer with a 1 to 2 -km baseline and seven 1.5 aperture elements arranged in a 'Y' configuration with a central beam combiner. The Submillimeter interferometer would use seven, 5-m reflectors in a 'Y' or circular configuration with a 1-km baseline. The Very Low Frequency (VLF) array would operate below 30 mHz with as many as 100 elements and a 200-km baseline.

Ideas for future large single dish radio telescopes

NASA Astrophysics Data System (ADS)

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.

Photoelectric array detectors for use at XUV wavelengths. [for Spacelab solar-physics facilities

NASA Technical Reports Server (NTRS)

Timothy, J. G.

1981-01-01

The characteristics of photoelectric detector systems for use at visible-light, ultraviolet, and X-ray wavelengths are briefly reviewed in the context of the needs of the Spacelab solar-physics facilities. Photoelectric array detectors for use at XUV wavelengths between 90 and 1500 A are described, and their use in the ESA Grazing-Incidence Solar Telescope (GRIST) facility is discussed.

EVA 2 activity on Flight Day 5 to survey the HST solar array panels

NASA Image and Video Library

1997-02-15

STS082-719-002 (14 Feb. 1997) --- Astronaut Joseph R. Tanner (right) stands on the end of Discovery's Remote Manipulator System (RMS) arm and aims a camera at the solar array panels on the Hubble Space Telescope (HST) as astronaut Gregory J. Harbaugh assists. The second Extravehicular Activity (EVA) photograph was taken with a 70mm camera from inside Discovery's cabin.

PNIC - A near infrared camera for testing focal plane arrays

NASA Astrophysics Data System (ADS)

Hereld, Mark; Harper, D. A.; Pernic, R. J.; Rauscher, Bernard J.

1990-07-01

This paper describes the design and the performance of the Astrophysical Research Consortium prototype near-infrared camera (pNIC) designed to test focal plane arrays both on and off the telescope. Special attention is given to the detector in pNIC, the mechanical and optical designs, the electronics, and the instrument interface. Experiments performed to illustrate the most salient aspects of pNIC are described.

HST Solar Arrays photographed by Electronic Still Camera

NASA Technical Reports Server (NTRS)

1993-01-01

This view, backdropped against the blackness of space shows one of two original Solar Arrays (SA) on the Hubble Space Telescope (HST). The scene was photographed with an Electronic Still Camera (ESC), and downlinked to ground controllers soon afterward. Electronic still photography is a technology which provides the means for a handheld camera to electronically capture and digitize an image with resolution approaching film quality.

Evolution, Nucleosynthesis, and Yields of Low-mass Asymptotic Giant Branch Stars at Different Metallicities. II. The FRUITY Database

NASA Astrophysics Data System (ADS)

Cristallo, S.; Piersanti, L.; Straniero, O.; Gallino, R.; Domínguez, I.; Abia, C.; Di Rico, G.; Quintini, M.; Bisterzo, S.

2011-12-01

By using updated stellar low-mass stars models, we systematically investigate the nucleosynthesis processes occurring in asymptotic giant branch (AGB) stars. In this paper, we present a database dedicated to the nucleosynthesis of AGB stars: FRANEC Repository of Updated Isotopic Tables & Yields (FRUITY). An interactive Web-based interface allows users to freely download the full (from H to Bi) isotopic composition, as it changes after each third dredge-up (TDU) episode and the stellar yields the models produce. A first set of AGB models, having masses in the range 1.5 <=M/M ⊙ <= 3.0 and metallicities 1 × 10-3 <= Z <= 2 × 10-2, is discussed. For each model, a detailed description of the physical and the chemical evolution is provided. In particular, we illustrate the details of the s-process and we evaluate the theoretical uncertainties due to the parameterization adopted to model convection and mass loss. The resulting nucleosynthesis scenario is checked by comparing the theoretical [hs/ls] and [Pb/hs] ratios to those obtained from the available abundance analysis of s-enhanced stars. On the average, the variation with the metallicity of these spectroscopic indexes is well reproduced by theoretical models, although the predicted spread at a given metallicity is substantially smaller than the observed one. Possible explanations for such a difference are briefly discussed. An independent check of the TDU efficiency is provided by the C-stars luminosity function. Consequently, theoretical C-stars luminosity functions for the Galactic disk and the Magellanic Clouds have been derived. We generally find good agreement with observations.

EVA 3 - Linnehan portrait

NASA Image and Video Library

2002-03-06

STS109-322-028 (6 March 2002) --- Astronaut Richard M. Linnehan, STS-109 mission specialist, participates in the third of five space walks to perform work on the Hubble Space Telescope (HST). Linnehan's sun shield reflects astronaut John M. Grunsfeld and the blue and white Earth's hemisphere as well as one of the telescope's new solar arrays. The third overall STS-109 extravehicular activity (EVA) marked the second of three for Linnehan and Grunsfeld, payload commander. On this particular walk, the two turned off the telescope in order to replace the power control unit or PCU--the heart of its power system. Grunsfeld took this photo with a 35mm camera.

Optical design of a CubeSat-compatible imaging spectrometer

NASA Astrophysics Data System (ADS)

Mouroulis, Pantazis; Van Gorp, Byron; Green, Robert O.; Wilson, Daniel W.

2014-09-01

We describe a fast, uniform, low-polarization imaging spectrometer and telescope system that can be integrated in a 6U CubeSat. The spectral range is 350-1700 nm, with 5.7 nm sampling. The telescope and spectrometer operate at F/1.8. At 100 mm focal length, the telescope is the highest resolution form that can fit in the CubeSat frame without deployable mirrors. The field of view is 10° with 600 cross-track pixels. The spectrometer is designed for the new Teledyne CHROMA detector array with 30μm pixel size for maximizing throughput. The primary intended applications are coastal ocean and snow cover monitoring.

STS-61 art concept of astronauts during HST servicing

NASA Image and Video Library

1993-11-12

S93-48826 (November 1993) --- This artist's rendition of the 1993 Hubble Space Telescope (HST) servicing mission shows astronauts installing the new Wide Field/Planetary Camera (WF/PC 2). The instruments to replace the original camera and contains corrective optics that compensate for the telescope's flawed primary mirror. During the 11-plus day mission, astronauts are also scheduled to install the Corrective Optics Space Telescope Axial Replacement (COSTAR) -- an optics package that focuses and routes light to the other three instruments aboard the observatory -- a new set of solar array panels, and other hardware and components. The artwork was done for JPL by Paul Hudson.

The possibility of gamma-ray astronomy measurements on the Russian segment of the International Space Station.

NASA Astrophysics Data System (ADS)

Fradkin, M. I.; Gorchakov, E. V.; Kaplin, V. A.; Kaplin, D. V.; Kurnosova, L. V.; Labenskij, A. G.; Runtso, M. F.; Topchiev, N. P.

The conditions required for gamma-ray astronomy measurements at energies of 10 - 1000 GeV by a gamma-ray telescope on the International Space Station are discussed. It is shown that the properties of the detected gamma rays can be determined accurately at 30 - 1000 GeV, even if the space station solar arrays fall in the aperture of the gamma-ray telescope. Measurements of the secondary gamma-ray spectrum using a ground-based model of the gamma-ray telescope have been carried out, and the resulting spectrum at energies of 1 - 100 GeV is presented.

Holographic beam mapping of the CHIME pathfinder array

NASA Astrophysics Data System (ADS)

Berger, Philippe; Newburgh, Laura B.; Amiri, Mandana; Bandura, Kevin; Cliche, Jean-François; Connor, Liam; Deng, Meiling; Denman, Nolan; Dobbs, Matt; Fandino, Mateus; Gilbert, Adam J.; Good, Deborah; Halpern, Mark; Hanna, David; Hincks, Adam D.; Hinshaw, Gary; Höfer, Carolin; Johnson, Andre M.; Landecker, Tom L.; Masui, Kiyoshi W.; Mena Parra, Juan; Oppermann, Niels; Pen, Ue-Li; Peterson, Jeffrey B.; Recnik, Andre; Robishaw, Timothy; Shaw, J. Richard; Siegel, Seth; Sigurdson, Kris; Smith, Kendrick; Storer, Emilie; Tretyakov, Ian; Van Gassen, Kwinten; Vanderlinde, Keith; Wiebe, Donald

2016-08-01

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder radio telescope is currently surveying the northern hemisphere between 400 and 800 MHz. By mapping the large scale structure of neutral hydrogen through its redshifted 21 cm line emission between z 0.8-2.5 CHIME will contribute to our understanding of Dark Energy. Bright astrophysical foregrounds must be separated from the neutral hydrogen signal, a task which requires precise characterization of the polarized telescope beams. Using the DRAO John A. Galt 26 m telescope, we have developed a holography instrument and technique for mapping the CHIME Pathfinder beams. We report the status of the instrument and initial results of this effort.

The MEarth Project: Status Update and the Commissioning of a Brand New Telescope Array in the Southern Hemisphere

NASA Astrophysics Data System (ADS)

Berta-Thompson, Zachory K.; Irwin, Jonathan; Charbonneau, David; Newton, Elisabeth R.; Dittmann, Jason

2014-06-01

The MEarth Project is an ongoing all-sky survey for Earth-like planets transiting the closest, smallest M dwarfs. MEarth aims to find good targets for atmospheric characterization with JWST and the next generation of enormous ground-based telescopes. MEarth's yearly data releases, containing precise light curves of nearby mid-to-late M dwarfs, provide a unique window into the photometric variability of the stars that will forever be among the most interesting targets in the search for potentially habitable exoplanets. We present a status update on the MEarth Project, including a detailed map of the progress we’ve made so far with 8 telescopes in the Northern hemisphere and promising early results from our new installation of 8 more telescopes in the Southern hemisphere.

Bubbles, voids, and bumps in time: The new cosmology

NASA Astrophysics Data System (ADS)

Cornell, James

The history and current status of theoretical and observational cosmology are examined in chapters based on the Lowell Lectures, given in Boston and Washington DC in spring 1987. Topics addressed include the Aristotelian, Copernican, Newtonian, and Einsteinian universes; the measurement of the universe (redshifts and standard candles); mapping the universe (slices and bubbles); dark matter and missing mass; and the big bang and cosmic inflation. Six basic outstanding problems are identified, and the potential contributions of planned ground-based and space observatories to their solution are discussed. Particular attention is given to CCD detectors for large ground-based telescopes, the VLA, VLBI arrays, the ESO Very Large Telescope, the 10-m Keck telescope on Mauna Kea, the Hubble Space Telescope, the Gamma-Ray Observatory, and the Advanced X-ray Astrophysics Facility.

Low-cost, high-resolution, single-structure array telescopes for imaging of low-earth-orbit satellites

NASA Technical Reports Server (NTRS)

Massie, N. A.; Oster, Yale; Poe, Greg; Seppala, Lynn; Shao, Mike

1992-01-01

Telescopes that are designed for the unconventional imaging of near-earth satellites must follow unique design rules. The costs must be reduced substantially over those of the conventional telescope designs, and the design must accommodate a technique to circumvent atmospheric distortion of the image. Apertures of 12 m and more along with altitude-altitude mounts that provide high tracking rates are required. A novel design for such a telescope, optimized for speckle imaging, has been generated. Its mount closely resembles a radar mount, and it does not use the conventional dome. Costs for this design are projected to be considerably lower than those for the conventional designs. Results of a design study are presented with details of the electro-optical and optical designs.

Operation of the University of Hawaii 2.2M telescope on Mauna Kea

NASA Technical Reports Server (NTRS)

Hall, Donald N. B.

1991-01-01

NASA's planetary astronomy program provides part of the funding for the 2.2 meter telescope. The parameters for time on the telescope are laid out. A major instrumental highlight has been the commissioning of a 256 x 256 near infrared camera which uses a Rockwell NICMOS-3 array. At the f/10 focus, image scales of 0.37 and 0.75 arcsec/pixel are available. A new, high quantum efficiency Tektronix 1024 x 1024 CCD saw first light on the telescope in 1991, and was available regularly from April 1991. Data from both of these detectors are transmitted directly to the Sun workstation for immediate analysis by the observers. The autoguider software was enhanced to permit guided tracking on objects have nonsideral motions (i.e., solar system objects).

Some design considerations for a synthetic aperture optical telescope array

NASA Astrophysics Data System (ADS)

Scott, P. W.

1984-01-01

Several design considerations inherent in the configuration of phased array transmission of multiwavelength laser beams are discussed. Attention is focused on the U.S.A.F. phased array (PHASAR) demonstration project, where problems have been encountered in dividing the beam(s), controlling the optical path differences between subapertures, and expanding individual beams.A piston-driven path length adjustment mechanism has been selected, along with an active control system and proven components for stability maintenance. The necessity of developing broadband, high reflectivity low phase shift coatings for the system mirrors is stressed.

Simulation and Testing of a Linear Array of Modified Four-Square Feed Antennas for the Tianlai Cylindrical Radio Telescope

NASA Astrophysics Data System (ADS)

Cianciara, Aleksander J.; Anderson, Christopher J.; Chen, Xuelei; Chen, Zhiping; Geng, Jingchao; Li, Jixia; Liu, Chao; Liu, Tao; Lu, Wing; Peterson, Jeffrey B.; Shi, Huli; Steffel, Catherine N.; Stebbins, Albert; Stucky, Thomas; Sun, Shijie; Timbie, Peter T.; Wang, Yougang; Wu, Fengquan; Zhang, Juyong

A wide bandwidth, dual polarized, modified four-square antenna is presented as a feed antenna for radio astronomical measurements. A linear array of these antennas is used as a line-feed for cylindrical reflectors for Tianlai, a radio interferometer designed for 21cm intensity mapping. Simulations of the feed antenna beam patterns and scattering parameters are compared to experimental results at multiple frequencies across the 650-1420MHz range. Simulations of the beam patterns of the combined feed array/reflector are presented as well.

The Southern Hemisphere VLBI experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preston, R.A.; Meier, D.L.; Louie, A.P.

1989-07-01

Six radio telescopes were operated as the first Southern Hemisphere VLBI array in April and May 1982. Observations were made at 2.3 and 8.4 GHz. This array provided VLBI modeling and hybrid imaging of celestial radio sources in the Southern Hemisphere, high-accuracy VLBI geodesy between Southern Hemisphere sites, and subarcsecond radio astrometry of celestial sources south of declination -45 deg. The goals and implementation of the array are discussed, the methods of modeling and hybrid image production are explained, and the VLBI structure of the sources that were observed is summarized. 36 refs.

International Agreement Will Advance Radio Astronomy

NASA Astrophysics Data System (ADS)

2007-12-01

Two of the world's leading astronomical institutions have formalized an agreement to cooperate on joint efforts for the technical and scientific advancement of radio astronomy. The National Radio Astronomy Observatory (NRAO) in the United States and the Max-Planck Institute for Radioastronomy (MPIfR) in Germany concluded a Memorandum of Understanding outlining planned collaborative efforts to enhance the capabilities of each other's telescopes and to expand their cooperation in scientific research. The VLBA The VLBA CREDIT: NRAO/AUI/NSF In the first project pursued under this agreement, the MPIfR will contribute $299,000 to upgrade the continent-wide Very Long Baseline Array's (VLBA) capability to receive radio emissions at a frequency of 22 GHz. This improvement will enhance the VLBA's scientific productivity and will be particularly important for cutting-edge research in cosmology and enigmatic cosmic objects such as gamma-ray blazars. "This agreement follows many years of cooperation between our institutions and recognizes the importance of international collaboration for the future of astronomical research," said Fred K.Y. Lo, NRAO Director. "Our two institutions have many common research goals, and joining forces to keep all our telescopes at the forefront of technology will be highly beneficial for the science," said Anton Zensus, Director at MPIfR. In addition to the VLBA, the NRAO operates the Very Large Array (VLA) in New Mexico and the Robert C. Byrd Green Bank Telescope (GBT) in West Virginia. The MPIfR operates the 100-meter Effelsberg Radio Telescope in Germany and the 12-meter APEX submillimeter telescope in 5100 m altitude in the Cilean Atacama desert (together with the European Southern Observatory and the Swedish Onsala Space Observatory). With the 100-meter telescope, it is part of the VLBA network in providing transatlantic baselines. Both institutions are members of a global network of telescopes (the Global VLBI Network) that uses simultaneous observations to produce extremely high-resolution images, and another network (the High Sensitivity Array) that uses the same technique with large telescopes to observe particularly faint celestial objects. With this technique, NRAO telescopes work with MPIfR's Effelsberg telescope to produce images hundreds of times more detailed than those from the Hubble Space Telescope. Both institutions also are part of the international collaboration building the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and of the international planning effort to build a Square Kilometer Array. The VLBA is a system of ten antennas, each with a dish 25 meters in diameter. From Mauna Kea on the Big Island of Hawaii to St. Croix in the U.S. Virgin Islands, the VLBA spans more than 8000 kilometers. Under the new agreement, the two institutions will continue their previous observational collaborations, and in addition will share resources to improve the technical capabilities of each other's telescopes, particularly at short wavelengths, They also will collaborate in the peer-reviewed process each uses to allocate observing time, and agree to mutually maintain an "open skies" policy allowing open access to each other's telescopes on a peer-reviewed basis. The agreement notes the report of the U.S. National Science Foundation's (NSF) Senior Review committee, which called upon the NRAO to seek partners to contribute to the operation of the VLBA. The MPIfR affirms its strong interest in maintaining the VLBA's unique scientific capabilities, and its monetary contribution toward the 22 GHz upgrade of the VLBA is a solid sign of that commitment. "The VLBA provides the greatest resolving power of any instrument in astronomy, and the MPIfR's contribution to enhancing its capabilities is an important validation of the VLBA's importance to frontier astrophysics," Lo said. The joint VLBA project calls for the MPIfR to fund the receiving-system upgrades and the NRAO to perform the work. The project is scheduled to be complete, with all 10 VLBA antennas upgraded, in August of 2008. The upgrade will make the VLBA's receiving system for 22 GHz 30 percent more sensitive. This will enhance the VLBA's capability to advance a key area of science using rotating disks of water molecules at the cores of distant galaxies to make precise measurements of the distances to those galaxies. This technique, first used in the late 1990s, can measure large cosmic distances directly, without relying on various assumptions required for more indirect techniques. The improved precision is important to resolving a number of frontier astrophysical problems, including the nature of the mysterious "dark energy" that appears to be accelerating the expansion of the Universe. This research project involves scientists from both MPIfR and NRAO, and, in addition to the VLBA, the Effelsberg telescope, the GBT and the VLA. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. The Max Planck Institute for Radio Astronomy is one of about 80 research institutes of the Max Planck Society for the Promotion of Research in Germany.

Inside NuSTAR Nose Cone

NASA Image and Video Library

2012-03-02

A spacecraft technician is performing closeout work inside the fairing that will be installed around NASA Nuclear Spectroscopic Telescope Array NuSTAR spacecraft in a processing facility at Vandenberg Air Force Base in California.