These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Expected Performance of Adaptive Optics in Large Aperture Solar Telescopes  

NASA Astrophysics Data System (ADS)

Solar adaptive optics has become an indispensable tool for high resolution solar observations. New generation solar telescopes, such as the 4 m aperture Advanced Technology Solar Telescope, introduce a new set of challenges to solar adaptive optics correction. Larger aperture sizes are more susceptible to the effects on AO correction performance of the extended field-of-view of the cross-correlating Shack-Hartmann wavefront sensor. Observations at large zenith angles further enhance these field-of-view effects and can introduce more performance reductions due to atmospheric dispersion. We study the expected correction performance of solar adaptive optics systems in large aperture solar telescopes using an end-to-end adaptive optics simulation package.

Marino, J.; Rimmele, T. R.

2012-12-01

2

Grazing Incidence Solar Telescope  

Microsoft Academic Search

The Grazing Incidence Solar Telescope (GRIST) described in this report is intended for flight in Spacelab and offers for the first time the combination of high spatial and spectral resolution in the XUV and EUV wavelength range. The telescope is a sector shaped Wolter type-2 paraboloid-hyperboloid mirror pair of 412 cm effective focal length, 280 sq cm aperture and 6

R. Pacault; G. P. Whitcomb

1981-01-01

3

Synthetic aperture radio telescopes  

Microsoft Academic Search

Next-generation radio telescopes will be much larger, more sensitive, have a much larger observation bandwidth, and will be capable of pointing multiple beams simultaneously. Obtaining the sensitivity, resolution, and dynamic range supported by the receivers requires the development of new signal processing techniques for array and atmospheric calibration as well as new imaging techniques that are both more accurate and

Ronny Levanda; Amir Leshem

2010-01-01

4

Large aperture diffractive space telescope  

DOEpatents

A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

Hyde, Roderick A. (Livermore, CA)

2001-01-01

5

Very Large Aperture Diffractive Space Telescope  

SciTech Connect

A very large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass ''aiming'' at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The magnifying glass includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the magnifying glass, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets.

Hyde, Roderick Allen

1998-04-20

6

Placement of multiple apertures for imaging telescopes  

SciTech Connect

Two techniques we have used for determining mirror positions in multiple-aperture telescope arrays are described. Our design criteria is the maximization of the contiguous central core diameter of the optical transfer function for the telescope system. The first technique is applicable to arrays with a relatively small, O(10), number of apertures and is essentially an exhaustive search with a simple in-line test which allows the search space to be pruned'' by an order of magnitude. In the second technique, arrays of a large number of apertures are designed using a fractal approach by recursively combining the results from several array patterns with fewer apertures. Both techniques are demonstrated for one and two dimensional designs and can be extended for higher dimensions if needed. 1 ref., 13 figs.

Fitch, J.P.; Lawrence, T.W.

1990-01-01

7

Placement of multiple apertures for imaging telescopes  

NASA Astrophysics Data System (ADS)

Two techniques we have used for determining mirror positions in multiple-aperture telescope arrays are described. Our design criteria is the maximization of the contiguous central core diameter of the optical transfer function for the telescope system. The first technique is applicable to arrays with a relatively small, O(10), number of apertures and is essentially an exhaustive search with a simple in-line test which allows the search space to be 'pruned' by an order of magnitude. In the second technique, arrays of a large number of apertures are designed using a fractal approach by recursively combining the results from several array patterns with fewer apertures. Both techniques are demonstrated for one and two dimensional designs and can be extended for higher dimensions if needed.

Fitch, J. P.; Lawrence, T. W.

1990-08-01

8

The solar optical telescope  

NASA Technical Reports Server (NTRS)

Objectives of the Solar Optical Telescope are to study the physics of the Sun on the scale at which many of the important physical processes occur and to attain a resolution of 73km on the Sun or 0.1 arc seconds of angular resolution. Topics discussed in this overview of the Solar Optical Telescope include: why is the Solar Optical Telescope needed; current picture of the Sun's atmosphere and convection zone; scientific problems for the Solar Optical Telescope; a description of the telescope; the facility - science management, contamination control, and accessibility to the instruments; the scientific instruments - a coordinated instrument package for unlocking the Sun's secrets; parameters of the coordinated instrument package; science operations from the Space Shuttle; and the dynamic solar atmosphere.

1990-01-01

9

Performance characteristics of phased array and thinned aperture optical telescopes  

NASA Technical Reports Server (NTRS)

While phased telescope arrays for general-purpose broadband imaging applications suffer severe sensitivity losses and field-of-view limitations, thinned-aperture telescopes consisting of a dilute, segmented primary mirror with a common secondary mirror are viable second-generation space telescope configurational possibilities yielding resolution and sensitivity an order of magnitude greater than those of the Hubble Space Telescope. Attention is given to thinned-aperture optical systems' image quality characterization problems; the 'practical resolution limit' image quality criterion proposed is defined as the reciprocal of the spatial frequency within which no zeros occur in the modulation transfer function.

Harvey, James E.; Rockwell, Richard A.

1987-01-01

10

Five hundred meter aperture spherical radio telescope (FAST)  

Microsoft Academic Search

Five hundred meter aperture spherical radio telescope (FAST) will be the largest radio telescope in the world. The innovative\\u000a engineering concept and design pave a new road to realizing a huge single dish in the most effective way. Three outstanding\\u000a features of the telescope are the unique karst depressions as the sites, the active main reflector which corrects spherical\\u000a aberration

Rendong Nan

2006-01-01

11

A 408MHz aperture synthesis radio telescope  

Microsoft Academic Search

This paper describes the addition of a continuum channel at 408 MHz to the Synthesis Telescope'at the Dominion Radio Astrophysical Observatory (DRAO). In its original form, described by Roger et al. [1973], the telescope was designed to receive signals at 1420 MHz and to provide simultaneous correlations of spectral line signals from the 21-cm wavelength line of atomic hydrogen (H

B. G. Veidt; T. L. Landecker; J. F. Vaneldik; P. E. Dewdney; D. Routledge

1985-01-01

12

Large diffractive/refractive apertures for space and airborne telescopes  

NASA Astrophysics Data System (ADS)

Recent work, specifically the Lawrence Livermore National Laboratory (LLNL) Eyeglass and the DARPA MOIRE programs, have evaluated lightweight, easily packaged and deployed, diffractive/refractive membrane transmissive lenses as entrance apertures for large space and airborne telescopes. This presentation describes a new, innovative approach to the theory of diffractive and refractive effects in lenses used as telescope entrance apertures and the fabrication of the necessary large membrane optics. Analyses are presented to indicate how a broadband, highly transmissive diffractive / refractive membrane lens can be developed and fabricated, and potential applications in defense and astronomy are briefly discussed.

MacEwen, Howard A.; Breckinridge, James B.

2013-05-01

13

Solar energy apparatus with apertured shield  

NASA Technical Reports Server (NTRS)

A protective apertured shield for use about an inlet to a solar apparatus which includesd a cavity receiver for absorbing concentrated solar energy. A rigid support truss assembly is fixed to the periphery of the inlet and projects radially inwardly therefrom to define a generally central aperture area through which solar radiation can pass into the cavity receiver. A non-structural, laminated blanket is spread over the rigid support truss in such a manner as to define an outer surface area and an inner surface area diverging radially outwardly from the central aperture area toward the periphery of the inlet. The outer surface area faces away from the inlet and the inner surface area faces toward the cavity receiver. The laminated blanket includes at least one layer of material, such as ceramic fiber fabric, having high infra-red emittance and low solar absorption properties, and another layer, such as metallic foil, of low infra-red emittance properties.

Collings, Roger J. (Inventor); Bannon, David G. (Inventor)

1989-01-01

14

Construction of the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

15

Low-Cost Large Aperture Telescopes for Optical Communications  

NASA Technical Reports Server (NTRS)

Low-cost, 0.5-1 meter ground apertures are required for near-Earth laser communications. Low-cost ground apertures with equivalent diameters greater than 10 meters are desired for deep-space communications. This presentation focuses on identifying schemes to lower the cost of constructing networks of large apertures while continuing to meet the requirements for laser communications. The primary emphasis here is on the primary mirror. A slumped glass spherical mirror, along with passive secondary mirror corrector and active adaptive optic corrector show promise as a low-cost alternative to large diameter monolithic apertures. To verify the technical performance and cost estimate, development of a 1.5-meter telescope equipped with gimbal and dome is underway.

Hemmati, Hamid

2006-01-01

16

The balloon-borne large aperture submillimeter telescope  

NASA Astrophysics Data System (ADS)

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is designed to produce large (1-100 deg 2 ) maps of the sky at 250, 350, and 500 pm. The balloon platform lifts BLAST above most of the atmosphere, which is nearly opaque in the submillimeter, making BLAST significantly more sensitive than existing ground-based submillimeter telescopes. BLAST has had three successful flights on a high-altitude balloon. This thesis is in three parts. In the first part, the design, construction, and operation of BLAST is described in detail. Specifically, the submillimeter telescope and receiver, the cryogenic system, the various pointing sensors, and the command and control systems are covered. The processes of launching and landing the gondola are also discussed. In the second part, the analysis of BLAST data is discussed, and specifically data from the BLAST05 flight. The process of cleaning and preparing bolometer time-streams for map-making is discussed. The process of calibrating the data, flat-fielding the bolometer responsivity, removing time-varying changes in bolometer responsivity, and absolute flux calibration based on the fluxes of a known astronomical submillimeter source is detailed. Reconstructing the pointing solution from the data from the in-flight pointing sensors is discussed. Finally, combining the calibrated bolometer data with the reconstructed pointing solution to generate maps is described. In the third part, BLAST05 flight data and results are presented. Several compact sources were mapped, including solar system, Galactic, and extragalactic targets. These included Pallas and Saturn in the solar system, K3-50, W 75N, IRAS 20126+4104, CRL 2688, IRAS 21078+5211, LDN 1014, IRAS 21307+5049, IRAS 22134+5834, and IRAS 23011+6126 in the Galaxy, and the galaxies NGC 4565, Mrk 231, and Arp 220. Fluxes and spectral energy distributions (SEDs) of each of these sources at the BLAST wavelengths are presented, and these are compared with previous measurements at other wavelengths. These results could be useful for the calibration of other submillimeter instruments. Finally, there is brief discussion of larger maps of Galactic regions.

Truch, Matthew David Patey

17

Advanced Technology Solar Telescope Construction: Progress Report  

NASA Astrophysics Data System (ADS)

The 4m Advance Technology Solar Telescope (ATST) on Haleakala will be the most powerful solar telescope and the world’s leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun’s output. The ATST will provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. With its 4 m aperture, ATST will resolve magnetic features at their intrinsic scales. A high order adaptive optics system delivers a corrected beam to the initial set of five state-of-the-art, facility class instrumentation located in the coude laboratory facility. Photopheric and chromospheric magnetometry is part of the key mission of four of these instruments. Coronal magnetometry and spectroscopy will be performed by two of these instruments at infrared wavelengths. The ATST project has transitioned from design and development to its construction phase. Site construction is expected to begin in April 2012. The project has awarded design and fabrication contracts for major telescope subsystems. A robust instrument program has been established and all instruments have passed preliminary design reviews or critical design reviews. A brief overview of the science goals and observational requirements of the ATST will be given, followed by a summary of the project status of the telescope and discussion of the approach to integrating instruments into the facility. The National Science Foundation (NSF) through the National Solar Observatory (NSO) funds the ATST Project. The NSO is operated under a cooperative agreement between the Association of Universities for Research in Astronomy, Inc. (AURA) and NSF.

Rimmele, Thomas R.; McMullin, J.; Keil, S.; Goode, P.; Knoelker, M.; Kuhn, J.; Rosner, R.; ATST Team

2012-05-01

18

National Large Solar Telescope of Russia  

NASA Astrophysics Data System (ADS)

One of the most important task of the modern solar physics is multi-wavelength observations of the small-scale structure of solar atmosphere on different heights, including chromosphere and corona. To do this the large-aperture telescopes are necessary. At present time there several challenging projects of the large (and even giant) solar telescopes in the world are in the process of construction or designing , the most known ones among them are 4-meter class telescopes ATST in USA and EST in Europe. Since 2013 the development of the new Large Solar Telescope (LST) with 3 meter diameter of the main mirror is started in Russia as a part (sub-project) of National Heliogeophysical Complex (NHGC) of the Russian Academy of Sciences. It should be located at the Sayan solar observatory on the altitude more then 2000 m. To avoid numerous problems of the off-axis optical telescopes (despite of the obvious some advantages of the off-axis configuration) and to meet to available financial budget, the classical on-axis Gregorian scheme on the alt-azimuth mount has been chosen. The scientific equipment of the LST-3 will include several narrow-band tunable filter devices and spectrographs for different wavelength bands, including infrared. The units are installed either at the Nasmyth focus or/and on the rotating coude platform. To minimize the instrumental polarization the polarization analyzer is located near diagonal mirror after M2 mirror. High order adaptive optics is used to achieve the diffraction limited performances. It is expected that after some modification of the optical configuration the LST-3 will operate as an approximately 1-m mirror coronograph in the near infrared spectral lines. Possibilities for stellar observations during night time are provided as well.

Demidov, Mikhail

19

The Advanced Technology Solar Telescope: beginning construction of the world's largest solar telescope  

NASA Astrophysics Data System (ADS)

The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. The project has successfully passed its final design review and the Environmental Impact Study for construction of ATST on Haleakala, Maui, HI has been concluded in December of 2009. The project is now entering its construction phase. As its highest priority science driver ATST shall provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. With its 4 m aperture, ATST will resolve features at 0."03 at visible wavelengths and obtain 0."1 resolution at the magnetically highly sensitive near infrared wavelengths. A high order adaptive optics system delivers a corrected beam to the initial set of state-of-the-art, facility class instrumentation located in the coudé laboratory facility. The initial set of first generation instruments consists of five facility class instruments, including imagers and spectropolarimeters. The high polarimetric sensitivity and accuracy required for measurements of the illusive solar magnetic fields place strong constraints on the polarization analysis and calibration. Development and construction of a fourmeter solar telescope presents many technical challenges, including thermal control of the enclosure, telescope structure and optics and wavefront control. A brief overview of the science goals and observational requirements of the ATST will be given, followed by a summary of the design status of the telescope and its instrumentation, including design status of major subsystems, such as the telescope mount assembly, enclosure, mirror assemblies, and wavefront correction

Rimmele, T. R.; Wagner, J.; Keil, S.; Elmore, D.; Hubbard, R.; Hansen, E.; Warner, M.; Jeffers, P.; Phelps, L.; Marshall, H.; Goodrich, B.; Richards, K.; Hegwer, S.; Kneale, R.; Ditsler, J.

2010-07-01

20

MOIRE: ground demonstration of a large aperture diffractive transmissive telescope  

NASA Astrophysics Data System (ADS)

The desire to field space-based telescopes with apertures in excess of 10 meter diameter is forcing the development of extreme lightweighted large optomechanical structures. Sparse apertures, shell optics, and membrane optics are a few of the approaches that have been investigated and demonstrated. Membrane optics in particular have been investigated for many years. The MOIRE approach in which the membrane is used as a transmissive diffractive optical element (DOE) offers a significant relaxation in the control requirements on the membrane surface figure, supports extreme lightweighting of the primary collecting optic, and provides a path for rapid low cost production of the primary optical elements. Successful development of a powered meter-scale transmissive membrane DOE was reported in 2012. This paper presents initial imaging results from integrating meter-scale transmissive DOEs into the primary element of a 5- meter diameter telescope architecture. The brassboard telescope successfully demonstrates the ability to collect polychromatic high resolution imagery over a representative object using the transmissive DOE technology. The telescope includes multiple segments of a 5-meter diameter telescope primary with an overall length of 27 meters. The object scene used for the demonstration represents a 1.5 km square complex ground scene. Imaging is accomplished in a standard laboratory environment using a 40 nm spectral bandwidth centered on 650 nm. Theoretical imaging quality for the tested configuration is NIIRS 2.8, with the demonstration achieving NIIRS 2.3 under laboratory seeing conditions. Design characteristics, hardware implementation, laboratory environmental impacts on imagery, image quality metrics, and ongoing developments will be presented.

Atcheson, Paul; Domber, Jeanette; Whiteaker, Kevin; Britten, Jerald A.; Dixit, Shamasundar N.; Farmer, Brandon

2014-08-01

21

Teaching and Research in Astronomy using Small Aperture Optical Telescopes  

NASA Astrophysics Data System (ADS)

Small aperture (<1m, typically 20-50cm) optical telescopes with adequate back-end instrumentation (photometer, CCD camera and CCD spectrograph etc) can be used for spreading the joy and excitement of observational astronomy among postgraduate and research students in Colleges/. On the basis of over a decade's experience in observing with small optical telescopes it has been amply demonstrated that such a facility, which any University department can hope to procure and maintain, can be effectively used for teaching as well quality research. The Physics Department of Pt Ravishankar Shukla University at Raipur, India offers Astronomy & Astrophysics (A&A) as one of the specialization as a part of M Sc program in Physics. A set of observational exercises has been incorporated with a view to provide training in observations, analysis and interpretation of the astronomical data to the students. Observing facilities available in the department include 8"-14" aperture telescopes (CGE series from Celestron) equipped with the new-state-of-the-art backend instrumentation like Photometer, CCD Camera and also a CCD spectrograph. Observing facility of this kind is ideally suited for continuous monitoring of a variety of variable stars, and thus can provide valuable data for understanding the physics of stellar variability. This is especially true for a class of variable stars known as chromospherically active stars. The stars belonging to this class have variable light curves, and the most puzzling feature is that their light curves change year after year in a rather queerer way. A large fraction of these active stars are bright ones and, hence, the importance of small aperture telescope for collecting the much needed photometric data. For over a decade the research activity using 14" optical telescope is focused on photometric monitoring of well known as well suspected active stars. This together with spectroscopic data using observing facility at Indian Observatories has led to identification of new chromosperically active stars. The talk is aimed at sharing our experiences quoting examples with professional colleagues on the usage of small optical telescopes for teaching and research in Colleges/Universities.

Pandey, S. K.

2006-08-01

22

Photometric Reverberation Mapping with a Small Aperture Telescope  

NASA Astrophysics Data System (ADS)

We present photometric observations of a sample of bright, broad-line AGN in order to monitor variability and verify their black hole masses using the photometric reverberation mapping technique. Observations were taken, primarily remotely, using the 20-inch telescope at the Murillo Family Observatory, a campus-based observatory located on the outskirts of the Southern California metro area, in both monitored and automated mode nightly in BVRI over a period of 2-5 months. We will show the viability of such a technique for small-aperture telescopes in bright-sky locations and discuss the possibilities of extending this program in the future. We also note that undergraduate students (both from 4-year and community colleges) have been and will continue to be instrumental in the success of similar research programs at CSUSB.

Hood, Carol E.; Rivera, Noah I.; Thackeray-Lacko, Beverly; Powers, Randy M.; Stuckey, Harrison; Watson, Rene; Hood, Michael A.

2015-01-01

23

The Advanced Technology Solar Telescope: Science Drivers and Construction Status  

NASA Astrophysics Data System (ADS)

The 4-meter Advance Technology Solar Telescope (ATST) currently under construction on the 3000 meter peak of Haleakala on Maui, Hawaii will be the world's most powerful solar telescope and the leading ground-based resource for studying solar magnetism. The solar atmosphere is permeated by a 'magnetic carpet' that constantly reweaves itself to control solar irradiance and its effects on Earth's climate, the solar wind, and space weather phenomena such as flares and coronal mass ejections. Precise measurement of solar magnetic fields requires a large-aperture solar telescope capable of resolving a few tens of kilometers on the solar surface. With its 4 meter aperture, the ATST will for the first time resolve magnetic structure at the intrinsic scales of plasma convection and turbulence. The ATST's ability to perform accurate and precise spectroscopic and polarimetric measurements of magnetic fields in all layers of the solar atmosphere, including accurate mapping of the elusive coronal magnetic fields, will be transformative in advancing our understanding of the magnetic solar atmosphere. The ATST will utilize the Sun as an important astro- and plasma-physics "laboratory" demonstrating key aspects of omnipresent cosmic magnetic fields. The ATST construction effort is led by the US National Solar Observatory. State-of-the-art instrumentation will be constructed by US and international partner institutions. The technical challenges the ATST is facing are numerous and include the design of the off-axis main telescope, the development of a high order adaptive optics system that delivers a corrected beam to the instrument laboratory, effective handling of the solar heat load on optical and structural elements, and minimizing scattered light to enable observations of the faint corona. The ATST project has transitioned from design and development to its construction phase. The project has awarded design and fabrication contracts for major telescope subsystems. Site construction has commenced following the successful conclusion of the site permitting process. Science goals and construction status of telescope and instrument systems will be discussed.

Rimmele, Thomas; Berger, Thomas; McMullin, Joseph; Keil, Stephen; Goode, Phil; Knoelker, Michael; Kuhn, Jeff; Rosner, Robert; Casini, Roberto; Lin, Haosheng; Woeger, Friedrich; von der Luehe, Oskar; Tritschler, Alexandra; Atst Team

2013-04-01

24

Hubble Space Telescope Solar Array  

NASA Technical Reports Server (NTRS)

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.

1985-01-01

25

XCAT: the JANUS x-ray coded aperture telescope  

NASA Astrophysics Data System (ADS)

The JANUS mission concept is designed to study the high redshift universe using a small, agile Explorer class observatory. The primary science goals of JANUS are to use high redshift (6Aperture Telescope (XCAT) and the Near-IR Telescope (NIRT) are the two primary instruments on JANUS. XCAT has been designed to detect bright X-ray flashes (XRFs) and gamma ray bursts (GRBs) in the 1-20 keV energy band over a wide field of view (4 steradians), thus facilitating the detection of z>6 XRFs/GRBs, which can be further studied by other instruments. XCAT would use a coded mask aperture design with hybrid CMOS Si detectors. It would be sensitive to XRFs and GRBs with flux in excess of approximately 240 mCrab. In order to obtain redshift measurements and accurate positions from the NIRT, the spacecraft is designed to rapidly slew to source positions following a GRB trigger from XCAT. XCAT instrument design parameters and science goals are presented in this paper.

Falcone, A. D.; Burrows, D. N.; Barthelmy, S.; Chang, W.; Fox, D.; Fredley, J.; Gehrels, N.; Kelly, M.; Klar, R.; Palmer, D.; Persyn, S.; Reichard, K.; Roming, P.; Seifert, E.; Smith, R. W. M.; Wood, P.; Zugger, M.

2010-07-01

26

Spacecraft Conceptual Design for the 8-Meter Advanced Technology Large Aperture Space Telescope (ATLAST)  

NASA Technical Reports Server (NTRS)

The Advanced Concepts Office at Marshall Space Flight Center completed a brief spacecraft design study for the 8-meter monolithic Advanced Technology Large Aperture Space Telescope (ATLAST-8m). This spacecraft concept provides all power, communication, telemetry, avionics, guidance and control, and thermal control for the observatory, and inserts the observatory into a halo orbit about the second Sun-Earth Lagrange point. The multidisciplinary design team created a simple spacecraft design that enables component and science instrument servicing, employs articulating solar panels for help with momentum management, and provides precise pointing control while at the same time fast slewing for the observatory.

Hopkins, Randall C.; Capizzo, Peter; Fincher, Sharon; Hornsby, Linda S.; Jones, David

2010-01-01

27

The Balloon-borne Large Aperture Submillimeter Telescope: BLAST  

E-print Network

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a sub-orbital surveying experiment designed to study the evolutionary history and processes of star formation in local galaxies (including the Milky Way) and galaxies at cosmological distances. The BLAST continuum camera, which consists of 270 detectors distributed between 3 arrays, observes simultaneously in broad-band (30%) spectral-windows at 250, 350, and 500 microns. The optical design is based on a 2m diameter telescope, providing a diffraction-limited resolution of 30" at 250 microns. The gondola pointing system enables raster mapping of arbitrary geometry, with a repeatable positional accuracy of ~30"; post-flight pointing reconstruction to ~5" rms is achieved. The on-board telescope control software permits autonomous execution of a pre-selected set of maps, with the option of manual override. In this paper we describe the primary characteristics and measured in-flight performance of BLAST. BLAST performed a test-flight in 2003 and has since made two scientifically productive long-duration balloon flights: a 100-hour flight from ESRANGE (Kiruna), Sweden to Victoria Island, northern Canada in June 2005; and a 250-hour, circumpolar-flight from McMurdo Station, Antarctica, in December 2006.

E. Pascale; P. A. R. Ade; J. J. Bock; E. L. Chapin; J. Chung; M. J. Devlin; S Dicker; M. Griffin; J. O. Gundersen; M. Halpern; P. C. Hargrave; D. H. Hughes; J. Klein; C. J. MacTavish; G. Marsden; P. G. Martin; T. G. Martin; P. Mauskopf; C. B. Netterfield; L. Olmi; G. Patanchon; M. Rex; D. Scott; C. Semisch; N. Thomas; M. D. P. Truch; C. Tucker; G. S. Tucker; M. P. Viero; D. V. Wiebe

2007-11-21

28

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

29

The Balloon-borne Large Aperture Sub-millimetre Telescope  

E-print Network

The Balloon-borne Large-Aperture Sub-millimetre Telescope (BLAST) will operate on a Long Duration Balloon platform with large format bolometer arrays at 250, 350 and 500 microns, initially using a 2m mirror, with plans to increase to 2.5m. BLAST is a collaboration between scientists in the USA, Canada, UK, Italy and Mexico. Funding has been approved and it is now in its building phase. The test flight is scheduled for 2002, with the first long duration flight the following year. The scientific goals are to learn about the nature of distant extragalactic star forming galaxies and cold pre-stellar sources by making deep maps both at high and low galactic latitudes. BLAST will be useful for planning Herschel key projects which use SPIRE.

Douglas Scott; the BLAST Team

2001-04-03

30

The Balloon-borne Large Aperture Sub-millimetre Telescope  

NASA Astrophysics Data System (ADS)

The Balloon-borne Large-Aperture Sub-millimetre Telescope (BLAST) will operate on a Long Duration Balloon platform with large format bolometer arrays at 250, 350 and 500 microns, initially using a 2.0 m mirror, with plans to increase to 2.5 m. BLAST is a collaboration between scientists in the USA, Canada, UK, Italy and Mexico. Funding has been approved and it is now in its building phase. The test flight is scheduled for 2002, with the first long duration flight the following year. The scientific goals are to learn about the nature of distant extragalactic star forming galaxies and cold pre-stellar sources by making deep maps both at high and low galactic latitudes. BLAST will be useful for planning Herschel key projects which use SPIRE.

Scott, D.; Ade, P.; Bock, J. J.; Debernardis, P.; Devlin, M.; Griffin, M. J.; Gundersen, J.; Halpern, M.; Hughes, D.; Klein, J.; Masi, S.; Mauskopf, P.; Netterfield, B.; Olmi, L.; Page, L.; Tucker, G.

2001-07-01

31

To appear in Proc. SPIE The Scaling Relationship Between Telescope Cost and Aperture Size for Very  

E-print Network

telescope, the cost data point was intended to be inclusive of telescope mirror, structure, enclosureTo appear in Proc. SPIE The Scaling Relationship Between Telescope Cost and Aperture Size for Very Large Telescopes Gerard T. van Belle1 Michelson Science Center, California Institute of Technology

van Belle, Gerard

32

The Advanced Technology Solar Telescope - Constructing The World's Largest Solar Telescope  

NASA Astrophysics Data System (ADS)

The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. The ATST shall provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. With its 4 m aperture, ATST will resolve features at 0.03" at visible wavelengths and obtain 0.1" resolution at the magnetically highly sensitive near infrared wavelengths. A high order adaptive optics system delivers a corrected beam to the initial set of five state-of-the-art, facility class instrumentation located in the coude laboratory facility. Coronal magnetometry and spectroscopy will be performed by two of these instruments at infrared wavelengths. In January 2010 the ATST project transitioned from design and development to the construction phase. The project has awarded contracts for major subsystems, including the 4m primary mirror, architectural and engineering services related to the Support Facilities, Enclosure construction design, Telescope Mount Assembly, and Facilities Thermal System construction design. The State of Hawai'I Board of Land and Natural Resources approved the Conservation District Use Permit submitted by the University of Hawai'I at their December 6, 2010 meeting in Honolulu, HI. A brief overview of the science goals and observational requirements of the ATST will be given, followed by a summary of the project status of the telescope and discussion of the approach to integrating instruments into the facility.

Rimmele, Thomas R.; Keil, S.; Wagner, J.; ATST Team

2011-05-01

33

BLAST: The Balloon-Borne Large Aperture Submillimeter Telescope  

NASA Technical Reports Server (NTRS)

BLAST is the Balloon-borne Large-Aperture Sub-millimeter Telescope. It will fly from a Long Duration Balloon (LDB) platform from Antarctica. The telescope design incorporates a 2 m primary mirror with large-format bolometer arrays operating at 250, 350 and 500 microns. By providing the first sensitive large-area (10 sq. deg.) sub-mm surveys at these wavelengths, BLAST will address some of the most important galactic and cosmological questions regarding the formation and evolution of stars, galaxies and clusters. Galactic and extragalactic BLAST surveys will: (1) identify large numbers of high-redshift galaxies; (2) measure photometric redshifts, rest-frame FIR luminosities and star formation rates thereby constraining the evolutionary history of the galaxies that produce the FIR and sub-mm background; (3) measure cold pre-stellar sources associated with the earliest stages of star and planet formation; (4) make high-resolution maps of diffuse galactic emission over a wide range of galactic latitudes. In addition to achieving the above scientific goals, the exciting legacy of the BLAST LDB experiment will be a catalogue of 3000-5000 extragalactic sub-mm sources and a 100 sq. deg. sub-mm galactic plane survey. Multi-frequency follow-up observations from SIRTF, ASTRO-F, and Herschel, together with spectroscopic observations and sub-arcsecond imaging from ALMA are essential to understand the physical nature of the BLAST sources.

Devlin, Mark; Ade, Peter; Bock, Jamie; Dicker, Simon; Griffin, Matt; Gunderson, Josh; Halpern, Mark; Hargrave, Peter; Hughes, David; Klein, Jeff

2004-01-01

34

Advanced Technology Solar Telescope: a progress report  

NASA Astrophysics Data System (ADS)

The four-meter Advanced Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. Development of a four-meter solar telescope presents many technical challenges (e.g., thermal control of the enclosure, telescope structure and optics). We give a status report of the ATST project (e.g., system design reviews, PDR, Haleakalä site environmental impact statement progress) and summarize the design of the major subsystems, including the telescope mount assembly, enclosure, mirror assemblies, wavefront correction, and instrumentation.

Wagner, J.; Rimmele, T. R.; Keil, S.; Hubbard, R.; Hansen, E.; Phelps, L.; Warner, M.; Goodrich, B.; Richards, K.; Hegwer, S.; Kneale, R.; Ditsler, J.

2008-07-01

35

The Telescope Control System of the New Solar Telescope at Big Bear Solar Observatory  

E-print Network

of the TCS as a distributed system including its several subsystems such as the Telescope Pointing maximizing ventilation. #12;Pointing and tracking telescope: TCS should be able to direct the telescopeThe Telescope Control System of the New Solar Telescope at Big Bear Solar Observatory G. Yang*a, J

36

Correlation tracking study for meter-class solar telescope on space shuttle. [solar granulation  

NASA Technical Reports Server (NTRS)

The theory and expected performance level of correlation trackers used to control the pointing of a solar telescope in space using white light granulation as a target were studied. Three specific trackers were modeled and their performance levels predicted for telescopes of various apertures. The performance of the computer model trackers on computer enhanced granulation photographs was evaluated. Parametric equations for predicting tracker performance are presented.

Smithson, R. C.; Tarbell, T. D.

1977-01-01

37

Solar System Observing Capabilities With The James Webb Space Telescope  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) will provide important new capabilities to study our Solar System. JWST is a large aperture, cryogenic, infrared-optimized space observatory under construction by NASA, ESA, and CSA for launch in 2018 into a L2 orbit. Imaging, spectroscopy, and coronography covers 0.6-29 microns. Integral-field spectroscopy is performed with apertures 3 to 7 arcsec square (spatial slices of 0.1 to 0.6 arcsec). JWST is designed to observe Solar System objects having apparent rates of motion up to 0.030 arcseconds/second. This tracking capability includes the planets, satellites, asteroids, Trans-Neptunian Objects, and comets beyond Earth’s orbit. JWST will observe in the solar elongation range of 85 to 135 degrees, and a roll range of +/-5 degrees about the telescope’s optical axis. During an observation of a moving target, the science target is held fixed in the desired science aperture by controlling the guide star to follow the inverse of the target’s trajectory. The pointing control software uses polynomial ephemerides for the target generated using data from JPL’s HORIZON system. The JWST guider field of view (2.2x2.2 arcmin) is located in the telescope focal plane several arcmin from the science apertures. The instrument apertures are fixed with respect to the telescope focal plane. For targets near the ecliptic, those apertures also have a nearly fixed orientation relative to the ecliptic. This results from the fact that the Observatory's sunshield and solar panels must always be between the telescope and the Sun. On-board scripts autonomously control the execution of the JWST science timeline. The event-driven scripts respond to actual slew and on-board command execution, making operations more efficient. Visits are scheduled with overlapping windows to provide execution flexibility and to avoid lost time. An observing plan covering about ten days will be uplinked weekly. Updates could be more frequent if necessary (for example, to accommodate a Target of Opportunity - TOO). The event-driven operations system supports time-critical observations and TOOs. The minimum response time for TOOs is 48 hours (observation approval to execution).

Sonneborn, George; Milam, S. N.; Hines, D. C.; Stansberry, J. A.; Hammel, H. B.; Lunine, J. I.

2014-01-01

38

Advanced Technology Solar Telescope optical design  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. Development of this four-meter off-axis solar telescope has presented many optical design challenges including: • support of both Nasmyth and flexible coude lab instrumentation, • incorporation of an integrated adaptive optics system, • thermal control of optics, and • optical alignment of multiple off-axis conics. This paper gives an overview of the optical design, error budgeting, and the performance modeling done to ensure the telescope will satisfy its optical performance requirements.

Hansen, Eric; Price, Ron; Hubbard, Rob

2006-06-01

39

The Revolution in Telescope Aperture C.M. Mountain and F.C. Gillett  

E-print Network

point representing a completed ground­based telescope. The combination of the ability to manufacture' The Revolution in Telescope Aperture C.M. Mountain and F.C. Gillett Gemini Observatory, 670 N. A that is often not recognised is the exponential growth in the total collecting area of large telescopes

40

The progress of Chinese Giant Solar Telescope  

NASA Astrophysics Data System (ADS)

Chinese Giant Solar Telescope (CGST) is the next generation ground-based solar telescope which was formally listed into the National Plans of Major Science and Technology Infrastructures. We have got series progresses of CGST in the recent years, from site testing to detailed designs. CGST is currently designed to be an 8m Ring Solar Telescope (RST). As an 8-meter solar telescope, the designing of CGST still faces some serious problems, although the ring structure is propitious to the thermo controlling and the high precision magnetic field measuring. The active control and the optical system of CGST are introduced. Then, simulations and the key calculations of the telescope, including the polarization analysis and the thermo calculation result are displayed. The present site testing methods and some results are introduced too. Finally, as the comparison in science and technology, the Chinese space solar telescope plans, such as the Deep Space Solar Observatory (DSO) and its progress are simply introduced.

Liu, Zhong; Jin, Zhenyu; Yuan, Shu; Lin, Jun; Deng, Yuanyong; Ji, Haisheng; Yan, Yihua

2014-07-01

41

Solar System Observing Capabilities With The James Webb Space Telescope  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) will provide breakthrough capabilities to study our Solar System. JWST is a large aperture, cryogenic, infrared-optimized space observatory under construction by NASA, ESA, and CSA for launch in 2018 into a L2 orbit. Imaging, spectroscopy, and coronography covers 0.6-29 microns. JWST is designed to observe Solar System objects having apparent rates of motion up to 0.030 arcseconds/second. This capability includes the planets, satellites, asteroids, Trans-Neptunian Objects, and comets beyond Earth’s orbit. JWST can observe solar elongation of 85 to 135 degrees, and a roll range of +/-5 degrees about the telescope’s optical axis. During the observation of a moving target, the science target is held fixed in the desired science aperture by controlling the guide star to follow the inverse of the target’s trajectory. The pointing control software uses polynomial ephemerides for the target generated using JPL’s HORIZON system. The JWST guider field of view (2.2x2.2 arcmin) is located in the telescope focal plane several arcmin from the science apertures. The instrument apertures are fixed with respect to the telescope focal plane. For targets near the ecliptic, those apertures also have a nearly-fixed orientation relative to the ecliptic. This resultsfrom the fact that the Observatory's sun-shade and solar panels must always be between the telescope and the Sun. On-board scripts autonomously control the execution of the JWST science timeline. The event-driven scripts respond to actual slew and on-board command execution, making operations more efficient. Visits are scheduled with overlapping windows to provide execution flexibility and to avoid lost time. An observing plan covering about ten days will be uplinked weekly. Updates could be more frequent if necessary (for example, to accommodate a Target of Opportunity - TOO). The event-driven operations system supports time-critical observations and TOOs. The minimum response time for TOOs is 48 hours (observation approval to execution).

Sonneborn, George; Milam, S. N.; Hines, D. C.; Stansberry, J.; Hammel, H. B.; Lunine, J. I.

2013-10-01

42

Construction of the Advanced Technology Solar Telescope - A Progress Report.  

NASA Astrophysics Data System (ADS)

The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. The ATST will provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. With its 4 m aperture, ATST will resolve magnetic features at their intrinsic scales. A high order adaptive optics system delivers a corrected beam to the initial set of five state-of-the-art, facility class instrumentation located in the coude laboratory facility. Photopheric and chromospheric magnetometry is part of the key mission of four of these instruments. Coronal magnetometry and spectroscopy will be performed by two of these instruments at infrared wavelengths. The ATST project has transitioned from design and development to its construction phase. Site construction is expected to begin in the first half of 2012. The project has awarded design and fabrication contracts for major telescope subsystems. A robust instrument program has been established and all instruments have passed preliminary design reviews or critical design reviews. A brief summary of the science goals and observational requirements of the ATST will be given, followed by a summary of the project status of the telescope and discussion of the approach to integrating instruments into the facility.

Rimmele, T. R.; Keil, S.; McMullin, J.; Goode, P. R.; Knoelker, M.; Kuhn, J. R.; Rosner, R.; ATST Team

2012-12-01

43

Development of adaptive optics elements for solar telescope  

NASA Astrophysics Data System (ADS)

The devices and components of adaptive optical system ANGARA, which is developed for image correction in the Big solar vacuum telescope (BSVT) at Baykal astrophysical observatory are described. It is shown that the use of modernized adaptive system on BSVT not only reduces the turbulent atmospheric distortions of image, but also gives a possibility to improve the telescope developing new methods of solar observations. A high precision Shack-Hartmann wavefront (WF) sensor has been developed on the basis of a low-aperture off-axis diffraction lens array. The device is capable of measuring WF slopes at array sub-apertures of size 640X640 ?m with an error not exceeding 4.80 arc.sec. Also the modification of this sensor for adaptive system of solar telescope using extended scenes as tracking objects, such as sunspot, pores, solar granulation and limb, is presented. The software package developed for the proposed WF sensors includes three algorithms of local WF slopes estimation (modified centroids, normalized cross-correlation and fast Fourier-demodulation), as well as three methods of WF reconstruction (modal Zernike polynomials expansion, deformable mirror response functions expansion and phase unwrapping), that can be selected during operation with accordance to the application.

Lukin, V. P.; Grigor'ev, V. M.; Antoshkin, L. V.; Botugina, N. N.; Kovadlo, P. G.; Konyaev, P. A.; Kopulov, E. A.; Skomorovsky, V. I.; Trifonov, V. D.; Chuprakov, S. A.

2012-07-01

44

Parallel Image Reconstruction for New Vacuum Solar Telescope  

NASA Astrophysics Data System (ADS)

Many advanced ground-based solar telescopes improve the spatial resolution of observation images using an adaptive optics (AO) system. As any AO correction remains only partial, it is necessary to use post-processing image reconstruction techniques such as speckle masking or shift-and-add (SAA) to reconstruct a high-spatial-resolution image from atmospherically degraded solar images. In the New Vacuum Solar Telescope (NVST), the spatial resolution in solar images is improved by frame selection and SAA. In order to overcome the burden of massive speckle data processing, we investigate the possibility of using the speckle reconstruction program in a real-time application at the telescope site. The code has been written in the C programming language and optimized for parallel processing in a multi-processor environment. We analyze the scalability of the code to identify possible bottlenecks, and we conclude that the presented code is capable of being run in real-time reconstruction applications at NVST and future large aperture solar telescopes if care is taken that the multi-processor environment has low latencies between the computation nodes.

Li, Xue-Bao; Wang, Feng; Xiang, Yong Yuan; Zheng, Yan Fang; Liu, Ying Bo; Deng, Hui; Ji, Kai Fan

2014-04-01

45

New high resolution solar telescope GREGOR  

NASA Astrophysics Data System (ADS)

The 1.5m solar telescope GREGOR is being constructed at Tenerife, Spain. Its purpose is to observe with high spatial and spectral resolution small-scale dynamic magnetic features on the Sun. The telescope is completely open with retractable dome and actively cooled primary mirror made of silicon carbide to minimize thermal effects on the image quality. After completion it will be one of the most powerful solar telescopes. This paper presents a general overview of the telescope characteristics and the current status.

Volkmer, R.; von der Lühe, O.; Kneer, F.; Staude, J.; Balthasar, H.; Berkefeld, T.; Caligari, P.; Collados, M.; Halbgewachs, C.; Heidecke, F.; Hofmann, A.; Klvańa, M.; Sobotka, M.; Nicklas, H.; Popow, E.; Puschmann, K. G.; Schmidt, W.; Soltau, D.; Strassmeier, K.; Wittmann, A. D.

46

Planning the 8-meter Chinese Giant Solar Telescope  

NASA Astrophysics Data System (ADS)

The Chinese Giant Solar Telescope (CGST) will be a diffraction limited solar telescope optimized for the near-infrared (NIR) spectral region (0.8 - 2.5 microns). Its diffraction limit will be reached by the incorporation of Multi-Conjugate Adaptive Optics (MCAO) enhanced by image restoration techniques to achieve uniform (u.v) plane coverage over the angular spatial frequency region allowed by its 8-meter aperture. Thus it will complement the imaging capabilities of 4-meter telescopes being planned elsewhere which are optimized for the visible (VIS) spectral region (300 - 1000 nm) In the NIR spectral regions the CGST will have access to unique spectral features which will improve the diagnostics of the solar atmosphere. These include the CaII lines near 860 nm , the HeI lines near 1083 nm, the 1074 nm FeXIII coronal lines, the large Zeeman-split FeI line at 1548 nm, and (v) the H- continuum absorption minimum at 1.6 micron. Especially in sunspot umbrae the simultaneous observation of continua and lines across the NIR spectral range will cover a substantial depth range in the solar atmosphere. Of course the mid- and far- infrared regions are also available for unequalled high-angular resolution solar observations, for example, in the Hydrogen Bracket lines, CO molecular bands, and the MgI emission line at 12.3 microns. The CGST is a so-called ring telescope in which the light is captured by a 1 meter wide segmented ring or by a ring of 7 smaller off-axis aperture telescopes. The open central area of the telescope is large. The advantages of such a ring configuration is that (a) it covers all the spatial frequencies out to those corresponding to its outer diameter, (b) its circular symmetry makes it polarization neutral, (c) its large central hole helps thermal control, and (d) it provides ample space for the MCAO system and instrumentation in the Gregorian focus. Even though optimized for the NIR, we expect to use the CGST also at visible wavelengths in the so-called “Partial Adaptive Optics” (PAO) mode (Applied Optics 31,424,1992) to obtain angular resolution twice that of a 4-meter telescope if their observations indicate that higher resolution is desirable. The CGST is a Chinese solar community project.

Beckers, Jacques M.; Liu, Z.; Deng, Y.; Ji, H.

2013-07-01

47

Design of a coded aperture Compton telescope imaging system (CACTIS)  

NASA Astrophysics Data System (ADS)

We have developed a prototype of a scalable high-resolution direction and energy sensitive gamma-ray detection system that operates in both coded aperture (CA) and Compton scatter (CS) modes to obtain optimal efficiency and angular resolution over a wide energy range. The design consists of an active coded aperture constructed from 52 individual CZT planar detectors each measuring 3×3×6 mm3 arranged in a MURA pattern on a 10×10 grid, with a monolithic 20×20×5 mm3 pixelated (8×8) CZT array serving as the focal plane. The combined mode is achieved by using the aperture plane array for both Compton scattering of high-energy photons and as a coded mask for low-energy radiation. The prototype instrument was built using two RENA-3 test systems, one each for the aperture and the focal plane, stacked on top of each other at a distance of 130 mm. The test systems were modified to coordinate (synchronize) readout and provide coincidence information of events within a user-adjustable 40-1,280 ns window. The measured angular resolution of the device is <1 deg (17 mrad) in CA mode and is predicted to be approximately 3 deg (54 mrad) in CS mode. The energy resolution of the CZT detectors is approximately 5% FWHM at 120 keV. We will present details of the system design and initial results for the calibration and performance of the prototype.

Volkovskii, Alexander; Clajus, Martin; Gottesman, Stephen R.; Malik, Hans; Schwartz, Kenneth; Tumer, Evren; Tumer, Tumay; Yin, Shi

2010-08-01

48

A Balloon-borne Large Aperture Submillimeter Telescope  

E-print Network

A new generation of sub-orbital platforms will be operational in the next few years. These new telescopes will operate from airborne and balloon-borne platforms where the atmosphere is transparent enough to allow sensitive measurements to be made in the submillimeter bands. The telescopes will take advantage of state-of-the-art instrumentation including large format bolometer arrays and spectrometers. Other papers in this volume will deal specifically with the potential of these bands. In this paper will review the capabilities the BLAST balloon-borne telescope.

Mark J. Devlin

2000-12-14

49

Advanced Technology Solar Telescope project management  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) has recently received National Science Foundation (NSF) approval to begin the construction process. ATST will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. This paper gives an overview of the project, and describes the project management principles and practices that have been developed to optimize both the project's success as well as meeting requirements of the project's funding agency.

Wagner, J.; Hansen, E.; Hubbard, R.; Rimmele, T. R.; Keil, S.

2010-07-01

50

The 100 cm solar telescope primary mirror study  

NASA Technical Reports Server (NTRS)

The manufacturing impact of primary mirror configuration on the performance of a 100 cm aperture solar telescope was studied. Three primary mirror configurations were considered: solid, standard lightweight, and mushroom. All of these are of low expansion material. Specifically, the study consisted of evaluating the mirrors with regard to: manufacturing metrology, manufacturing risk factors and ultimate quality assessment. As a result of this evaluation, a performance comparison of the configurations was made, and a recommendation of mirror configuration is the final output. These evaluations, comparisons and recommendations are discussed in detail. Other investigations were completed and are documented in the appendices.

1975-01-01

51

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

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

52

Large-Aperture, Three Mirror Telescopes for Near-Earth  

NASA Astrophysics Data System (ADS)

In this era when Space Situational Awareness (SSA) is a national priority and optical-infrared telescopic sensor development is underway, cost-benefit analyses of competing approaches are necessary and appropriate. The DOD is presently investing in a new three-mirror telescope for SSA. At the same time, the Air Force, various universities and private research organizations are either studying or building wide-field telescopes with similar capabilities, but in most cases, at a significantly lower cost. Much of the expense for the DOD system appears driven by certain design choices which were advertised as necessary to fulfill the mission. Design details which would allow an independent analysis have not been published and no public comparison with other approaches is known to exist. Most telescope designs however, can be closely approximated from their optical configuration and imaging performance specifications. An optical designer will tell you that field curvature is one of the five monochromatic aberrations which they try to eliminate. The fact that one DOD development effort considers field curvature a design feature immediately draws attention to the project. This coupled with the paucity of published information and the very high development cost makes this program irresistible for comparison with competing approaches. This paper examines the likely design and performance of a proxy telescope intended to find NEOs, compares and contrasts that telescope with similar, but lower cost on-going projects, and examines the predictable impacts of reproducing such a telescope and placing multiple copies around the globe. The study primarily concentrates on performance measured in terms of search rate in square degrees per hour vs. object visual magnitude. Other considerations such as cost, transportability, availability of replacement components and ease of installation are also considered.

Ackermann, M.; McGraw, J.

53

Solar object tracking for the Hubble Space Telescope  

NASA Technical Reports Server (NTRS)

The Hubble Space Telescope (HST) is designed to carry five major scientific instruments to collect imagery, spectrographic, and photometric astronomical data. The Pointing Control System is to achieve pointing accuracies and line of sight jitter levels an order of magnitude less than can be achieved with ground mounted telescopes. In addition, the HST must be able to acquire and track solar system targets with apparent motion up to 0.21 arcsec/s. Such targets include planetary satellites, planetary surface features and comets. It is to perform this tracking with an accuracy under 0.03 arcsec at the maximum rate. Tracking of solar objects by the Space Telescope accounts for the effects of velocity aberration and parallax, as well as solar targeting a celestial object in a science instrument aperture. The design of the Pointing Control System solar object tracking features is discussed, with emphasis on the special timing and granulation problems inherent with a sampled-data, multirate digital control system.

Rodden, J. J.; Dougherty, H. J.

1987-01-01

54

Solar observations with the Multi-Spectral Solar Telescope Array  

NASA Technical Reports Server (NTRS)

The Multi-Spectral Solar Telescope Array (MSSTA) is a sounding rocket-borne solar observatory which was succesfully launched on May 13, 1991, from the White Sands Missile Range, NM. Ultrahigh resolution, full-disk solar X-ray, EUV, and FUV images were obtained with the MSSTA Herschelian, Cassegrain, and Ritchey-Chretien telescopes. We describe the payload and provide some preliminary scientific results from the flight.

Hoover, Richard B.; Walker, Arthur B. C., Jr.; Lindblom, Joakim; Allen, Maxwell; O'Neal, Ray; Deforest, Craig; Barbee, Troy W., Jr.

1992-01-01

55

Low-cost Large Aperture Telescopes for Optical Communications  

NASA Technical Reports Server (NTRS)

Low-cost, large-aperture optical receivers are required to form an affordable optical ground receiver network for laser communications. Among the ground receiver station's multiple subsystems, here, we only discuss the ongoing research activities aimed at reducing the cost of the large-size optics on the receiver. Experimental results of two different approaches for fabricating low-cost mirrors of wavefront quality on the order of 100-200X the diffraction limit are described. Laboratory-level effort are underway to improve the surface figure to better than 20X the diffraction limit.

Hemmati, Hamid

2006-01-01

56

The Balloon-borne Large Aperture Submillimeter Telescope Peter Adea, Itziar Aretxagab, James Bockc, Jaspaul Chungd, Mark Devline, Simon Dickere,  

E-print Network

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) Peter Adea, Itziar Aretxagab with unprecedented image fidelity. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) will be one of the first experiments to make full use of this new capability. The high altitude ( 35 km) of the balloon

Aretxaga, Itziar

57

Recent enhancements of the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed at MSFC  

Microsoft Academic Search

Recent incremental upgrades to the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed have enabled the demonstration of phasing (with a monochromatic source) of clusters of primary mirror segments down to the diffraction limit. PAMELA upgrades include an improved Shack-Hartmann wavefront sensor, passive viscoelastic damping treatments for the voice-coil actuators, and mechanical improvement of mirror surface figures. This report

John M. Rakoczy; Edward E. Montgomery; Jeffrey L. Lindner

2000-01-01

58

Dynamics and control of a 25-meter aperture virtual structure Gossamer telescope in GEO  

NASA Technical Reports Server (NTRS)

In this paper we conduct a feasibility analysis of a 25-meter aperture virtual-structure space telescope example concept based on formation control of separated free-flying optical modules orbiting the Earth at GEO. We develop a Formation Flying implementation approach, and design and analyze the dynamics, control, metrology and estimation methods.

Mettler, E.; Quadrelli, M.; Breckenrisge, W.

2002-01-01

59

Development of large aperture cooled telescopes for the space infrared telescope for cosmology and astrophysics (SPICA) mission  

NASA Astrophysics Data System (ADS)

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) mission is the third Japanese astronomical infrared satellite project of a 3.5m cooled telescope optimized for mid- to far-infrared observations, following the Infrared Telescope in Space (IRTS) and the ASTRO-F missions. It will employ mechanical coolers and an efficient radiative cooling system, which allow us to have a cooled (4.5K) telescope of the aperture much larger than previous missions in space. The SPICA will attack a number of key problems in present-day astrophysics, ranging from the origin of the universe to the formation of planetary systems, owing to its high spatial resolution and unprecedented sensitivity in the mid- to far-infrared. The large aperture size for cryogenically use is, however, a great challenge and demands substantial technology developments for the telescope system. We adopt monolithic mirror design in the baseline model because of the technical feasibility and reliability. We set the optical performance requirement as being diffraction limited at 5?m at the operating temperature of 4.5K. The total weight attributed to the telescope system is 700kg, which requires a very light 3.5m primary mirror together with the mirror support structure. At present we are working on two candidate materials for the SPICA telescope: silicon carbide (SiC) and carbon-fiber reinforced silicon carbide (C/SiC). This presentation gives a general overview of the SPICA mission and reports the current design and status of the SPICA telescope system, including recent progress of the development of C/SiC mirrors.

Onaka, Takashi; Kaneda, Hidehiro; Enya, Keigo; Nakagawa, Takao; Murakiami, Hiroshi; Matsuhara, Hideo; Kataza, Hirokazu

2005-09-01

60

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: Calibration and Targeted Sources  

E-print Network

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 100-hour flight from northern Sweden in June 2005 (BLAST05). As part of the calibration and pointing procedures, several compact sources were mapped, including solar system, Galactic, and extragalactic targets, specifically Pallas, CRL 2688, LDN 1014, IRAS 20126+4104, IRAS 21078+5211, IRAS 21307+5049, IRAS 22134+5834, IRAS 23011+6126, K3-50, W 75N, and Mrk 231. One additional source, Arp 220, was observed and used as our primary calibrator. Details of the overall BLAST05 calibration procedure are discussed here. The BLAST observations of each compact source are described, flux densities and spectral energy distributions are reported, and these are compared with previous measurements at other wavelengths. The 250, 350, and 500 um BLAST data can provide useful constraints to the amplitude and slope of the submillimeter continuum, which in turn may be useful for the improved calibration of other submillimeter instruments.

M. D. P. Truch; P. A. R. Ade; J. J. Bock; E. L. Chapin; M. J. Devlin; S. Dicker; M. Griffin; J. O. Gundersen; M. Halpern; P. C. Hargrave; D. H. Hughes; J. Klein; G. Marsden; P. G. Martin; P. Mauskopf; C. B. Netterfield; L. Olmi; E. Pascale; G. Patanchon; M. Rex; D. Scott; C. Semisch; C. Tucker; G. S. Tucker; M. P. Viero; D. V. Wiebe

2008-03-31

61

Thermal Analysis of the Advanced Technology Large Aperture Space Telescope (ATLAST) 8 Meter Primary Mirror  

NASA Technical Reports Server (NTRS)

The Advanced Technology Large Aperture Space Telescope (ATLAST) preliminary design concept consists of an 8 meter diameter monolithic primary mirror enclosed in an insulated, optical tube with stray light baffles and a sunshade. ATLAST will be placed in orbit about the Sun-Earth L2 and will experience constant exposure to the sun. The insulation on the optical tube and sunshade serve to cold bias the telescope which helps to minimize thermal gradients. The primary mirror will be maintained at 280K with an active thermal control system. The geometric model of the primary mirror, optical tube, sun baffles, and sunshade was developed using Thermal Desktop(R) SINDA/FLUINT(R) was used for the thermal analysis and the radiation environment was analyzed using RADCAD(R). A XX node model was executed in order to characterize the static performance and thermal stability of the mirror during maneuvers. This is important because long exposure observations, such as extra-solar terrestrial planet finding and characterization, require a very stable observatory wave front. Steady state thermal analyses served to predict mirror temperatures for several different sun angles. Transient analyses were performed in order to predict thermal time constant of the primary mirror for a 20 degree slew or 30 degree roll maneuver. This paper describes the thermal model and provides details of the geometry, thermo-optical properties, and the environment which influences the thermal performance. All assumptions that were used in the analysis are also documented. Parametric analyses are summarized for design parameters including primary mirror coatings and sunshade configuration. Estimates of mirror heater power requirements are reported. The thermal model demonstrates results for the primary mirror heated from the back side and edges using a heater system with multiple independently controlled zones.

Hornsby, Linda; Stahl, H. Philip; Hopkins, Randall C.

2010-01-01

62

The Advanced Technology Solar Telescope mount assembly  

NASA Astrophysics Data System (ADS)

When constructed on the summit of Haleakala on the island of Maui, Hawaii, the Advanced Technology Solar Telescope (ATST) will be the world's largest solar telescope. The ATST is a unique design that utilizes a state-of-the-art off-axis Gregorian optical layout with five reflecting mirrors delivering light to a Nasmyth instrument rotator, and nine reflecting mirrors delivering light to an instrument suite located on a large diameter rotating coude lab. The design of the telescope mount structure, which supports and positions the mirrors and scientific instruments, has presented noteworthy challenges to the ATST engineering staff. Several novel design solutions, as well as adaptations of existing telescope technologies to the ATST application, are presented in this paper. Also shown are plans for the control system and drives of the structure.

Warner, Mark; Cho, Myung; Goodrich, Bret; Hansen, Eric; Hubbard, Rob; Lee, Joon Pyo; Wagner, Jeremy

2006-06-01

63

Detection and initial characterisation of an exoplanet atmosphere with small aperture telescopes  

NASA Astrophysics Data System (ADS)

In the recent years atmospheres of exoplanets have been studied with space-based telescopes like the HST or large aperture ground-based telescopes like the Gran Telescopio Canarias. But as the number of suitable exoplanets is rising, comparative studies of atmospheres with a statistically meaningful amount of targets will follow, for which the observational time with large telescopes is limited and expensive. Our aim is to investigate whether it is possible to detect and initially characterise the atmosphere of an exoplanet with small aperture telescopes using chromatic variations in transit depths. We collected multi-color transits in the years 2011 to 2013 using the robotic 1.2m-telescope STELLA on Tenerife as well as the Nordic Optical Telescope and the 70cm-telescope at the Leibniz Institute for Astrophysics Potsdam. The highly inflated Hot Jupiter HAT-P-32 b was chosen as target for our pilot study for its favorable large atmospheric scale height and therefore enhanced atmospheric detectability. Models of the atmospheric spectra of HAT-P-32 b indicate that the STELLA-data can be used to distinguish between a dusty and a cloud-free atmosphere using the gradient in transit depth of the observations in the blue band and in the visible band. Here we want to present our project together with the first results of the transit depth analysis.

Bernt, I.; Müller, M.; Strassmeier, K. G.; Granzer, T.

2013-09-01

64

The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers and Technology Developments  

NASA Technical Reports Server (NTRS)

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers and the resulting performance requirements for ATLAST (8 to 16 milliarcsecond angular resolution, diffraction limited imaging at 0.5 m wavelength, minimum collecting area of 45 square meters, high sensitivity to light wavelengths from 0.1 m to 2.4 m, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to current generation observatory-class space missions. Keywords: Advanced Technology Large-Aperture Space Telescope (ATLAST); ultraviolet/optical space telescopes; astrophysics; astrobiology; technology development.

Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Phillip; Tumlinson, Jason; Mountain, Matt; Soummer, Remi; Hyde, Tupper

2011-01-01

65

Layered synthetic microstructures for solar EUV telescopes  

NASA Technical Reports Server (NTRS)

The application of layered synthetic microstructures (LSMs) to figured mirrors suitable for normal incidence solar EUV telescopes is considered, and initial studies for a single mirror telescope consisting of an f/18, 200-cm focal length off-axis paraboloid demonstrate the feasibility of LSM coatings for moderate sized mirrors. Analytical studies on broadband designs comprised of five layers show a seven percent reflectance at 256 A and reflectivities of over 12 percent for wavelengths above 300 A. Deposition considerations are also discussed.

Keski-Kuha, R. A. M.; Thomas, R. J.; Epstein, G. L.; Osantowski, J. F.

1985-01-01

66

New high resolution solar telescope GREGOR  

Microsoft Academic Search

The 1.5m solar telescope GREGOR is being constructed at Tenerife, Spain. Its purpose is to observe with high spatial and spectral resolution small-scale dynamic magnetic features on the Sun. The telescope is completely open with retractable dome and actively cooled primary mirror made of silicon carbide to minimize thermal effects on the image quality. After completion it will be one

R. Volkmer; O. von der Lühe; F. Kneer; J. Staude; H. Balthasar; T. Berkefeld; P. Caligari; M. Collados; C. Halbgewachs; F. Heidecke; A. Hofmann; M. Klvańa; M. Sobotka; H. Nicklas; E. Popow; K. G. Puschmann; W. Schmidt; D. Soltau; K. Strassmeier; A. D. Wittmann

2007-01-01

67

Design of a telescope pointing and tracking subsystem for the Big Bear Solar Observatory New Solar Telescope  

Microsoft Academic Search

The New Solar Telescope at Big Bear Solar Observatory will use a distributed system to control the telescope, dome, adaptive optics, thermal environment and instrumentation. The Telescope Pointing and Tracking Subsystem has the tasks of controlling the telescope dome and acting as a wrapper for the telescope mount software (provided by the mount manufacturer) and adding the specific control features

J. R. Varsik; G. Yang

2006-01-01

68

NLST: India's National Large Solar Telescope  

NASA Astrophysics Data System (ADS)

This article introduces the new Indian 2 m telescope which has been designed by MT Mechatronics in a detailed conceptual design study for the Indian Institute of Astrophysics, Bangalore. We describe the background of the project and the science goals which shall be addressed with this telescope. NLST is a solar telescope with high optical throughput and will be equipped with an integrated Adaptive Optics system. It is optimized for a site with the kind of seeing and wind conditions as they are expected at a lake site in the Himalayan mountains. The telescope can also be used for certain night time applications. We also give the scientific rationale for this class of telescope.

Hasan, S. S.; Soltau, D.; Kärcher, H.; Süß, M.; Berkefeld, T.

2010-06-01

69

Dynamic Aperture-based Solar Loop Segmentation  

NASA Technical Reports Server (NTRS)

A new method to automatically segment arc-like loop structures from intensity images of the Sun's corona is introduced. The method constructively segments credible loop structures by exploiting the Gaussian-like shape of loop cross-sectional intensity profiles. The experimental results show that the method reasonably segments most of the well-defined loops in coronal images. The method is only the second published automated solar loop segmentation method. Its advantage over the other published method is that it operates independently of supplemental time specific data.

Lee, Jon Kwan; Newman, Timothy S.; Gary, G. Allen

2006-01-01

70

Design of a telescope pointing and tracking subsystem for the Big Bear Solar Observatory New Solar Telescope  

E-print Network

Design of a telescope pointing and tracking subsystem for the Big Bear Solar Observatory New Solar, adaptive optics, thermal environment and instrumentation. The Telescope Pointing and Tracking Sub- system solar telescope. These include features for offset pointing to specific regions on the solar disk

71

XCAT: The JANUS X-Ray Coded Aperture Telescope  

NASA Astrophysics Data System (ADS)

GRBs offer a unique window into the high redshift universe. GRBs 050904, 080913, and 090423 proved that bright optical GRB afterglows can be used to measure the star formation rate and to probe galaxies and the IGM out to at least z 8, and in principle they can be detected out to z 12. At present, we have no way of immediately measuring the redshift from space, and must rely on ground-based redshift measurements of GRBs discovered by Swift and other spacecraft to find high redshift bursts. This introduces long delays in the identification of high redshift bursts. JANUS is a proposed mission that is designed to measure GRB redshifts on-board and to announce the redshifts within minutes of the GRB onset, thus enabling ground-based spectro-scopic efforts to concentrate on afterglows known to be at high z. JANUS features a burst detector optimized for high redshift bursts (XCAT) and a near IR telescope with low resolution spectroscopy (NIRT). Here we describe the XCAT instrument.

Kennea, Jamie; Burrows, David; Falcone, Abraham; Fox, Derek; Palmer, David; Gehrels, Neil; Barthelmy, Scott

72

Solar optical telescope primary mirror controller  

NASA Technical Reports Server (NTRS)

The development of a technique to control the articulated primary mirror (APM) of the solar optical telescope (SOT) is discussed. Program results indicate that a single, all digital controller has sufficient capability to totally handle the computational requirements for control of the SOT APM.

Brown, R. J.; Liu, D.

1980-01-01

73

ATLAST-9.2m: a Large-Aperture Deployable Space Telescope  

NASA Technical Reports Server (NTRS)

We present results of a study of a deployable version of the Advanced Technology Large-Aperture Space Telescope (ATLAST), designed to operate in a Sun-Earth L2 orbit. The primary mirror of the segmented 9.2-meter aperture has 36 hexagonal 1.315 m (flat to flat) glass mirrors. The architecture and folding of the telescope is similar to JWST, allowing it to fit into the 6.5 m fairing of a modest upgrade to the Delta-IV Heavy version of the Evolved Expendable Launch Vehicle (EELV). We discuss the overall observatory design, optical design, instruments, stray light, wavefront sensing and control, pointing and thermal control, and in-space servicing options.

Oergerle, William; Feinberg, Lee D.; Purves, Lloyd R.; Hyde, T. Tupper; Thronson, Harley A.; Townsend, Jacqueline A.; Postman, Marc; Bolear, Matthew R.; Budinoff, Jason G.; Dean, Bruce H.; Clampin, Mark C.; Ebbets, Dennis C.; Gong, Qian; Gull, Theodore R.; Howard, Joseph M.; Jones, Andrew L.; Lyon, Richard G.; Pasquale, Bert A.; Perrygo, Charles; Smith, Jeffrey S.; Thompson, Patrick L.; Woodgate, Bruce E.

2010-01-01

74

Advanced Technology Solar Telescope: A status report  

NASA Astrophysics Data System (ADS)

Magnetic fields control the inconstant Sun. The key to understanding solar variability and its direct impact on the Earth rests with understanding all aspects of these magnetic fields. The Advanced Technology Solar Telescope (ATST) has been design specifically for magnetic remote sensing. Its collecting area, spatial resolution, scattered light, polarization properties, and wavelength performance all insure ATST will be able to observe magnetic fields at all heights in the solar atmosphere from photosphere to corona. After several years of design efforts, ATST has been approved by the U.S. National Science Foundation to begin construction with a not to exceed cost cap of approximately $298M. Work packages for major telescope components will be released for bid over the next several months. An application for a building permit has been submitted.

Keil, S. L.; Rimmele, T. R.; Wagner, J.; ATST Team

2010-06-01

75

AUTOMATIC GUIDING OF THE PRIMARY IMAGE OF SOLAR GREGORY TELESCOPES  

E-print Network

as a dark dot on the sensor. Pointing errors introduced by the telescope affect shifts of the solar imageAUTOMATIC GUIDING OF THE PRIMARY IMAGE OF SOLAR GREGORY TELESCOPES G. KĂ?VELER1, E. WIEHR2, D of solar Gregory telescopes is used for automatic guiding. This new system avoids temporal varying

76

Recent Enhancements of the Phased Array Mirror Extendible Large Aperture (PAMELA) Telescope Testbed at MSFC  

NASA Technical Reports Server (NTRS)

Recent incremental upgrades to the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed have enabled the demonstration of phasing (with a monochromatic source) of clusters of primary mirror segments down to the diffraction limit. PAMELA upgrades include an improved Shack-Hartmann wavefront sensor, passive viscoelastic damping treatments for the voice-coil actuators, mechanical improvement of mirror surface figures, and optical bench baffling. This report summarizes the recent PAMELA upgrades, discusses the lessons learned, and presents a status of this unique testbed for wavefront sensing and control. The Marshall Space Flight Center acquired the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope in 1993 after Kaman Aerospace was unable to complete integration and testing under the limited SDIO and DARPA funding. The PAMELA is a 36-segment, half-meter aperture, adaptive telescope which utilizes a Shack-Hartmann wavefront sensor, inductive coil edge sensors, voice coil actuators, imaging CCD cameras and interferometry for figure alignment, wavefront sensing and control. MSFC originally obtained the PAMELA to supplement its research in the interactions of control systems with flexible structures. In August 1994, complete tip, tilt and piston control was successfully demonstrated using the Shack-Hartmann wavefront sensor and the inductive edge sensors.

Rakoczy, John; Montgomery, Edward E.; Lindner, Jeff

2000-01-01

77

Recent Enhancements of the Phased Array Mirror Extendible Large Aperture (PAMELA) Telescope Testbed at MSFC  

NASA Technical Reports Server (NTRS)

Recent incremental upgrades to the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed have enabled the demonstration of phasing (with a monochromatic source) of clusters of primary mirror segments down to the diffraction limit. PAMELA upgrades include in improved Shack-Hartmann wavefront sensor, passive viscoelastic damping treatments for the voice-coil actuators, mechanical improvement of mirror surface figures, and optical bench baffling. This report summarizes the recent PAMELA upgrades, discusses the lessons learned, and presents a status of this unique testbed for wavefront sensing and control. The Marshall Space Flight Center acquired the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope in 1993 after Kaman Aerospace was unable to complete integration and testing under the limited SDIO and DARPA funding. The PAMELA is a 36-segment, half-meter aperture, adaptive telescope which utilizes a Shack-Hartmann wavefront sensor, inductive coil edge sensors, voice coil actuators, imaging CCD cameras and interferometry for figure alignment, wavefront sensing and control. MSFC originally obtained the PAMELA to supplement its research in the interactions of control systems with flexible structures. In August 1994, complete tip, tilt and piston control was successfully demonstrated using the Shack-Hartmann wavefront sensor and the inductive edge sensors.

Rakoczy, John; Burdine, Robert (Technical Monitor)

2001-01-01

78

Solar System Science with Robotic Telescopes  

NASA Astrophysics Data System (ADS)

An increasing number of sky surveys is already on-line or soon will be, leading to a large boost in the detection of Solar System objects of all types. For Near-Earth Objects (NEOs) that could potentially hit the Earth, timely follow-up is essential. I describe the development of an automated system which responds to new detections of NEOs from Pan-STARRS and automatically observes them with the LCOGT telescopes. I present results from the first few months of operation, and plans for the future with the 6-site, 40-telescope global LCOGT Network.

Lister, T. A.

2012-04-01

79

Cornell Caltech Atacama Telescope (CCAT): a 25-m aperture telescope above 5000-m altitude  

NASA Astrophysics Data System (ADS)

Cornell, California Institute of Technology (Caltech), and Jet Propulsion Lab (JPL) have joined together to study development of a 25 meter sub-millimeter telescope (CCAT) on a high peak in the Atacama region of northern Chile, where the atmosphere is so dry as to permit observation at wavelengths as short as 200 ?m. The telescope is designed to deliver high efficiency images at that wavelength with a total one-half wavefront error of about 10 ?m. With a 20 arc min field of view, CCAT will be able to accommodate large format bolometer arrays and will excel at carrying out surveys as well as resolving structures to the 2 arc sec resolution level. The telescope will be an ideal complement to ALMA. Initial instrumentation will include both a wide field bolometer camera and a medium resolution spectrograph. Studies of the major telescope subsystems have been performed as part of an initial Feasibility Concept Study. Novel aspects of the telescope design include kinematic mounting and active positioning of primary mirror segments, high bandwidth secondary mirror segment motion control for chopping, a Calotte style dome of 50 meter diameter, a mount capable of efficient scanning modes of operation, and some new approaches to panel manufacture. Analysis of telescope performance and of key subsystems will be presented to illustrate the technical feasibility and pragmatic cost of CCAT. Project plans include an Engineering Concept Design phase followed by detailed design and development. First Light is planned for early 2012.

Sebring, Thomas A.; Giovanelli, Riccardo; Radford, Simon; Zmuidzinas, Jonas

2006-06-01

80

First light of the 1.6 meter off-axis New Solar Telescope at Big Bear Solar Observatory  

NASA Astrophysics Data System (ADS)

New Jersey Institute of Technology, in collaboration with the University of Hawaii and the Korea Astronomy & Space Science Institute, has successfully developed and installed a 1.6 m clear aperture, off-axis New Solar Telescope (NST) at the Big Bear Solar Observatory. The NST will be the largest aperture solar telescope in the world until the 4 m Advanced Technology Solar Telescope (ATST) and 4 m European Solar Telescope (EST) begin operation in the next decade. Meanwhile, the NST will be the largest off-axis telescope before the 8.4 m segmented Giant Magellan Telescope (GMT) comes on-line. The NST is configured as an off-axis Gregorian system consisting of a parabolic primary, prime focus field stop and heat reflector, elliptical secondary and diagonal flats. The primary mirror is made of Zerodur from Schott and figured to a final residual error of 16 nm rms by Steward Observatory Mirror Lab. The final focal ratio is f/52. The 180 circular opening in the field stop defines the maximal square field-of-view. The working wavelength range will cover 0.4 to 1.7 ?m in the Coud´e Lab two floors beneath the telescope, and all wavelengths including far infrared at the Nasmyth focus on an optical bench attached to the side of the telescope structure. First-light scientific observations have been attained at the Nasmyth focus and in the Coud´e Lab. This paper presents a detailed description of installation and alignment of the NST. First-light observational results are also shown to demonstrate the validity of the NST optical alignment.

Cao, Wenda; Gorceix, Nicolas; Coulter, Roy; Coulter, Aaron; Goode, Philip R.

2010-07-01

81

Extreme adaptive optics imaging with a clear and well-corrected off-axis telescope sub-aperture  

Microsoft Academic Search

Rather than using an adaptive optics (AO) system to correct a telescope s\\u000aentire pupil, it can instead be used to more finely correct a smaller\\u000asub-aperture. Indeed, existing AO systems can be used to correct a sub-aperture\\u000a1\\/3 to 1\\/2 the size of a 5-10 m telescope to extreme adaptive optics (ExAO)\\u000alevels. We discuss the potential performance of

E. Serabyn; K. Wallace; M. Troy; B. Mennesson; P. Haguenauer; R. Gappinger; R. Burruss

2007-01-01

82

Aperture Shield Materials Characterized and Selected for Solar Dynamic Space Power System  

NASA Technical Reports Server (NTRS)

The aperture shield in a solar dynamic space power system is necessary to prevent thermal damage to the heat receiver should the concentrated solar radiation be accidentally or intentionally focused outside of the heat receiver aperture opening and onto the aperture shield itself. Characterization of the optical and thermal properties of candidate aperture shield materials was needed to support the joint U.S./Russian solar dynamic space power effort for Mir. The specific objective of testing performed at the NASA Lewis Research Center was to identify a high-temperature material with a low specular reflectance, a low solar absorptance, and a high spectral emittance so that during an off-pointing event, the amount of solar energy reflecting off the aperture shield would be small, the ratio of solar absorptance to spectral emittance would provide the lowest possible equilibrium temperature, and the integrity of the aperture shield would remain intact.

1995-01-01

83

Solar rejection for an orbiting telescope  

NASA Technical Reports Server (NTRS)

The present work discusses some of the constraints that the optical designer must deal with in optimizing spaceborne sensors that must look at or near the sun. Analytical techniques are described for predicting the effects of stray radiation from sources such as mirror scatter, baffle scatter, diffraction, and ghost images. In addition, the paper describes a sensor design that has been flown on the Apollo Telescope Mount (Skylab) to aid astronauts in locating solar flares. In addition to keeping stray radiation to a minimum, the design had to be nondegradable by the direct solar heat load.

Rehnberg, J. D.

1975-01-01

84

Review of the Solar Array Telescopes  

E-print Network

For several years the only experiments sensitive to astrophysical gamma rays with energies beyond the reach of EGRET but below that of the Cherenkov imaging telescopes have been the "solar tower" detectors. They use >2000 m2 mirror areas to sample the Cherenkov wavefront generated by <100 GeV gamma rays, obtaining Crab sensitivities of more than 6$\\sigma$ in one ON-source hour. I will review the history of the solar tower Cherenkov experiments from 1992 to the present and their key design features. I will describe some successful analysis strategies, then summarize the principal results obtained.

David A. Smith

2006-08-11

85

1.8-M solar telescope in China: the CLST  

NASA Astrophysics Data System (ADS)

For better understanding and forecasting of the solar activity and the corresponding impacts human technologies and life on earth, the high resolution observations for Sun are needed. The Chinese Large Solar Telescope (CLST) with 1.8 m aperture is being built. The CLST is a classic Gregorian configuration telescope with open structure, alt-azimuth mount, retractable dome, and a large mechanical de-rotator. The optical system with all reflective design has the field of view of larger than 3 arc-minute. The 1.8 m primary mirror is a honeycomb sandwiches fused silica lightweight mirror with ULE material and active cooling. The adaptive optics system will be developed to provide the capability for diffraction limited observations at visible wavelengths. The CLST design and development phase began in 2011 and 2012 respectively. We plan for the CLST's starting of commission in 2017. A multi-wavelength tomographic imaging system with seven wavelengths range from visible to near-infrared wavelength is considered as the first light scientific instruments. In this paper the main system configuration and the corresponding post focal instruments are described. Furthermore, the latest progress and current status of the CLST are also reported.

Rao, Changhui; Gu, Naiting; Zhu, Lei; Liu, Yangyi; Huang, Jinlong; Li, Cheng; Cheng, Yuntao; Cao, Xuedong; Zhang, Ming; Zhang, Lanqiang; Liu, Hong; Wan, Yongjian; Xian, Hao; Ma, Wenli; Bao, Hua; Zhang, Xiaojun; Guan, Chunlin; Chen, Donghong; Li, Mei

2014-07-01

86

The unique scientific capabilities of the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The 4 m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. We provide an overview of the science goals and observational requirements of the ATST and a brief summary of the design status of the telescope and its instrumentation.

Rimmele, T. R.; ATST Team

2008-07-01

87

Recent enhancements of the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed at MSFC  

NASA Astrophysics Data System (ADS)

Recent incremental upgrades to the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed have enabled the demonstration of phasing (with a monochromatic source) of clusters of primary mirror segments down to the diffraction limit. PAMELA upgrades include an improved Shack-Hartmann wavefront sensor, passive viscoelastic damping treatments for the voice-coil actuators, and mechanical improvement of mirror surface figures. This report summarizes the recent PAMELA upgrades and presents a status of this unique testbed for wavefront sensing and control. The Marshall Space Flight Center acquired the PAMELA telescope in 1993 after Kaman Aerospace was unable to complete integration and testing under the limited SDIO and DARPA funding. The PAMELA is a 36-segment, half-meter aperture, adaptive telescope which utilizes a Shack-Hartmann wavefront sensor, inductive coil edge sensors, voice coil actuators, imaging CCD cameras and interferometry for figure alignment, wavefront sensing and control. MSFC originally obtained the PAMELA to supplement its research in the interactions of control systems with flexible structures. In August 1994, complete tip, tilt and piston control was successfully demonstrated using the Shack-Hartmann wavefront sensor and the inductive edge sensors.

Rakoczy, John M.; Montgomery, Edward E.; Lindner, Jeffrey L.

2000-08-01

88

Polarimetric calibration of large-aperture telescopes. I. Beam-expansion method.  

PubMed

A concept is described for the high-accuracy absolute calibration of the instrumental polarization introduced by the primary mirror of a large-aperture telescope. This procedure requires a small aperture with polarization-calibration optics (e.g., mounted on the dome) followed by a lens that opens the beam to illuminate the entire surface of the mirror. The Jones matrix corresponding to this calibration setup (with a diverging incident beam) is related to that of the normal observing setup (with a collimated incident beam) by an approximate correction term. Numerical models of parabolic on-axis and off-axis mirrors with surface imperfections are used to explore the accuracy of the procedure. PMID:15770992

Socas-Navarro, Hector

2005-03-01

89

ATLAST-9.2: A Deployable Large Aperture UVOIR Space Telescope  

NASA Technical Reports Server (NTRS)

We present the results of a study of a deployable version of the Advanced Technology Large Aperture Space Telescope (ATLAST) that could be launched on an Evolved Expendable Launch Vehicle (EELV). ATLAST is a concept for a next-generation UVOIR observatory to follow HST and JWST. The observatory retains significant heritage from JWST, thereby taking advantage of technologies and engineering already developed for that mission. At the same time, we have identified several design changes to the JWST architecture, some of which are required due to the demanding wavefront error requirements at visible wavelengths. The optical telescope assembly has a segmented 9.2-meter aperture and consists of 36 hexagonal glass mirrors, each of which is I.3l5m in size (flat-to-flat). The telescope can be folded to fit in the 6.5m fairing on the planned upgrade to the Delta-IV heavy launch vehicle. Near-real time wavefront sensing and control is performed on-board the telescope using stars in the field of view to deliver diffraction limited imaging performance at 500nm wavelength. The optical design of the telescope provides an 8x20 arcmin FOV in which 4-5 instruments can be accommodated, plus fine guidance and wavefront sensors. Unlike JWST, the OTA sits at the end of a multi-gimbaled arm, allowing pitch and roll motion, and is isolated from the sunshield and spacecraft bus by an active isolation system. Our design permits servicing in order to extend the life of the observatory.

Oegerle, William R.; Feinberg, L.; Purves, L.; Hyde, T.; Thronson, H.; Townsend, J.; Postman, M.; Bolcar, M.; Budinoff, J.; Dean, B.; Clampin, N.; Ebbets, D.; Gong, Q.; Gull, T.; Howard, J.; Jones, A.; Lyon, R.; Pasquale, B.; Perrygo, C.; Smith, S.; Thompson, P.; Woodgate, B.

2010-01-01

90

The Five-hundred-meter Aperture Spherical radio Telescope project and its early science opportunities  

NASA Astrophysics Data System (ADS)

The National Astronomical Observatories, Chinese Academy of Science (NAOC), has started building the largest antenna in the world. Known as FAST, the Five-hundred-meter Aperture Spherical radio Telescope is a Chinese mega-science project funded by the National Development and Reform Commission (NDRC). FAST also represents part of Chinese contribution to the international efforts to build the square kilometer array (SKA). Upon its finishing around September of 2016, FAST will be the most sensitive single-dish radio telescope in the low frequency radio bands between 70 MHz and 3 GHz. The design specifications of FAST, its expected capabilities, and its main scientific aspirations were described in an overview paper by Nan et al. (2011). In this paper, we briefly review the design and the key science goals of FAST, speculate the likely limitations at the initial stages of FAST operation, and discuss the opportunities for astronomical discoveries in the so-called early science phase.

Li, Di; Nan, Rendong; Pan, Zhichen

2013-03-01

91

The Balloon-borne Large Aperture Submillimetre Telescope (BLAST) and BLASTPol  

NASA Astrophysics Data System (ADS)

Balloon observations from Antarctica have proven an effective and efficient way to address open Cosmological questions as well as problems in Galactic astronomy. The Balloon-borne Large Aperture Submillimetre Telescope (BLAST) is a sub-orbital mapping experiment which uses 270 bolometric detectors to image the sky in three wavebands centred at 250, 350 and 500 ?m with a 1.8 m telescope. In the years before Herschel launched, BLAST provided data of unprecedented angular and spectral coverage in frequency bands close to the peak of dust emission in star forming regions in our Galaxy, and in galaxies at cosmological distances. More recently, BLASTPol was obtained by reconfiguring the BLAST focal plane as a submillimetric polarimeter to study the role that Galactic magnetic fields have in regulating the processes of star-formation. The first and successful BLASTPol flight from Antarctica in 2010 is followed by a second flight, currently scheduled for the end of 2012.

Pascale, Enzo; Pascale

2013-01-01

92

The Advanced Technology Solar Telescope enclosure  

NASA Astrophysics Data System (ADS)

Telescope enclosure design is based on an increasingly standard set of criteria. Enclosures must provide failsafe protection in a harsh environment for an irreplaceable piece of equipment; must allow effective air flushing to minimize local seeing while still attenuating wind-induced vibration of the telescope; must reliably operate so that the dome is never the reason for observatory down time; must provide access to utilities, lifting devices and support facilities; and they must be affordable within the overall project budget. The enclosure for the Advanced Technology Solar Telescope (ATST) has to satisfy all these challenging requirements plus one more. To eliminate so-called external dome seeing, the exterior surfaces of the enclosure must be maintained at or just below ambient air temperature while being subjected to the full solar loading of an observing day. Further complicating the design of the ATST enclosure and support facilities are the environmental sensitivities and high construction costs at the selected site - the summit of Haleakala on the island of Maui, Hawaii. Previous development work has determined an appropriate enclosure shape to minimize solar exposure while allowing effective interior flushing, and has demonstrated the feasibility of controlling the exterior skin temperature with an active cooling system. This paper presents the evolution of the design since site selection and how the enclosure and associated thermal systems have been tailored to the particular climatic and terrain conditions of the site. Also discussed are load-reduction strategies that have been identified through thermal modeling, CFD modeling, and other analyses to refine and economize the thermal control systems.

Phelps, L.; Barr, J.; Dalrymple, N.; Fraser, M.; Hubbard, R.; Wagner, J.; Warner, M.

2006-06-01

93

Ray-tracing and physical-optics analysis of the aperture efficiency in a radio telescope  

NASA Astrophysics Data System (ADS)

The performance of telescope systems working at microwave or visible-IR wavelengths is typically described in terms of different parameters according to the wavelength range. Most commercial ray-tracing packages have been specifically designed for use with visible-IR systems and thus, though very flexible and sophisticated, do not provide the appropriate parameters to fully describe microwave antennas and to compare with specifications. We demonstrate that the Strehl ratio is equal to the phase efficiency when the apodization factor is taken into account. The phase efficiency is the most critical contribution to the aperture efficiency of an antenna and the most difficult parameter to optimize during the telescope design. The equivalence between the Strehl ratio and the phase efficiency gives the designer/user of the telescope the opportunity to use the faster commercial ray-tracing software to optimize the design. We also discuss the results of several tests performed to check the validity of this relationship that we carried out using a ray-tracing software, ZEMAX, and a full Physical Optics software, GRASP9.3, applied to three different telescope designs that span a factor of ?10 in terms of D/?. The maximum measured discrepancy between phase efficiency and Strehl ratio varies between ?0.4% and 1.9% up to an offset angle of >40 beams, depending on the optical configuration, but it is always less than 0.5% where the Strehl ratio is >0.95.

Olmi, Luca; Bolli, Pietro

2007-07-01

94

Ray-tracing and physical-optics analysis of the aperture efficiency in a radio telescope.  

PubMed

The performance of telescope systems working at microwave or visible-IR wavelengths is typically described in terms of different parameters according to the wavelength range. Most commercial ray-tracing packages have been specifically designed for use with visible-IR systems and thus, though very flexible and sophisticated, do not provide the appropriate parameters to fully describe microwave antennas and to compare with specifications. We demonstrate that the Strehl ratio is equal to the phase efficiency when the apodization factor is taken into account. The phase efficiency is the most critical contribution to the aperture efficiency of an antenna and the most difficult parameter to optimize during the telescope design. The equivalence between the Strehl ratio and the phase efficiency gives the designer/user of the telescope the opportunity to use the faster commercial ray-tracing software to optimize the design. We also discuss the results of several tests performed to check the validity of this relationship that we carried out using a ray-tracing software, ZEMAX, and a full Physical Optics software, GRASP9.3, applied to three different telescope designs that span a factor of approximately 10 in terms of D/lambda. The maximum measured discrepancy between phase efficiency and Strehl ratio varies between approximately 0.4% and 1.9% up to an offset angle of >40 beams, depending on the optical configuration, but it is always less than 0.5% where the Strehl ratio is >0.95. PMID:17571151

Olmi, Luca; Bolli, Pietro

2007-07-01

95

Optimizing the search for high-z GRBs:. the JANUS X-ray coded aperture telescope  

NASA Astrophysics Data System (ADS)

We discuss the optimization of gamma-ray burst (GRB) detectors with a goal of maximizing the detected number of bright high-redshift GRBs, in the context of design studies conducted for the X-ray transient detector on the JANUS mission. We conclude that the optimal energy band for detection of high-z GRBs is below about 30 keV. We considered both lobster-eye and coded aperture designs operating in this energy band. Within the available mass and power constraints, we found that the coded aperture mask was preferred for the detection of high-z bursts with bright enough afterglows to probe galaxies in the era of the Cosmic Dawn. This initial conclusion was confirmed through detailed mission simulations that found that the selected design (an X-ray Coded Aperture Telescope) would detect four times as many bright, high-z GRBs as the lobster-eye design we considered. The JANUS XCAT instrument will detect 48 GRBs with z>5 and fluence S_x > 3 × 10-7 erg cm-2 in a two year mission.

Burrows, D. N.; Fox, D.; Palmer, D.; Romano, P.; Mangano, V.; La Parola, V.; Falcone, A. D.; Roming, P. W. A.

96

Optimizing the Search for High-z GRBs: The JANUS X-ray Coded Aperture Telescope  

E-print Network

We discuss the optimization of gamma-ray burst (GRB) detectors with a goal of maximizing the detected number of bright high-redshift GRBs, in the context of design studies conducted for the X-ray transient detector on the JANUS mission. We conclude that the optimal energy band for detection of high-z GRBs is below about 30 keV. We considered both lobster-eye and coded aperture designs operating in this energy band. Within the available mass and power constraints, we found that the coded aperture mask was preferred for the detection of high-z bursts with bright enough afterglows to probe galaxies in the era of the Cosmic Dawn. This initial conclusion was confirmed through detailed mission simulations that found that the selected design (an X-ray Coded Aperture Telescope) would detect four times as many bright, high-z GRBs as the lobster-eye design we considered. The JANUS XCAT instrument will detect 48 GRBs with z > 5 and fluence Sx > 3 {\\times} 10-7 erg cm-2 in a two year mission.

Burrows, D N; Palmer, D; Romano, P; Mangano, V; La Parola, V; Falcone, A D; Roming, P W A

2011-01-01

97

The pre-research of the deploy technology for the large aperture space astronomical telescope  

NASA Astrophysics Data System (ADS)

The spherical primary mirror (Mb) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is segmented and composed of 37 hexagonal sub-mirrors, and segmented active optics method is successfully developed in it. LAMOST project has passed through the project acceptance in 2009. The success of LAMOST makes deployable primary mirror possible. The deployable large aperture space astronomical telescope is one of the most development potential space observation spacecrafts in the future. This paper is targeted at the reflecting Schmidt telescope LAMOST, which has a 6.67X6.05m primary mirror. The feasibility of the deployable structure of the large reflecting space telescope's primary mirror has been mainly researched. The analysis of the design scheme for the deployable primary mirror has been carried out, and according to the feature and the design of LAMOST, a subdivision type deployment scheme has been given; The locating principle of the both side wings and the locking device after deployment has been analyzed; In addition the problems in the process of deployment is also preliminary discussed. This paper is targeted at the reflecting Schmidt telescope LAMOST, which has a 6.67X6.05 primary mirror. The feasibility of the deployable structure of the large reflecting telescope's primary mirror has been mainly researched. The analysis of the design scheme for the deployable primary mirror has been carried out, and according to the feature and the design of LAMOST, a subdivision type deployment scheme has been given; The locating principle of the both side wings and the locking device after deployment has been analyzed; In addition the problems in the process of deployment have been preliminary discussed.

Jiang, Fanghua; Zuo, Heng; Li, Guoping

2012-09-01

98

The First Flight of ProtoEXIST1: Advanced Prototype CZT Coded Aperture Telescope  

NASA Astrophysics Data System (ADS)

ProtoEXIST1 is a pathfinder for the EXIST-HET, a coded aperture hard X-ray telescope with a 4.5 m2 CZT detector plane a 90x70 degree field of view to be flown as the primary instrument on the EXIST mission and is intended to monitor the full sky every 3 h in an effort to locate GRBs and other high energy transients. ProtoEXIST1 consists of a 256 cm2 tiled CZT detector plane containing 4096 pixels composed of an 8x8 array of individual 2.0x2.0 cm2 CZT detector modules each with a 8x8 pixilated anode configured as a coded aperture telescope with a fully coded 10x10 degree field of view employing passive side shielding and an active CsI anti-coincidence rear shield, recently completed its maiden flight out of Ft. Sumner, NM on the 9th of October 2009. During the duration of its 6 hour flight on-board calibration of the detector plane was carried out utilizing a single tagged 198 nCi Am-241 source along with the simultaneous measurement of the background spectrum and an observation of Cygnus X-1. Here we recount the events of the flight and report on the detector performance in a near space environment.

Allen, Branden; Hong, J.; Grindlay, J.; Barthelmy, S.; Baker, R.; Gehrels, N.; Garson, A.; Krawczynski, H.; Cook, W.; Harrison, F.

2010-02-01

99

Multiple-etalon systems for the Advanced Technology Solar Telescope  

NASA Technical Reports Server (NTRS)

Multiple etalon systems are discussed that meet the science requirements for a narrow-passband imaging system for the 4-meter National Solar Observatory (NSO)/Advance Technology Solar Telescope (ATST). A multiple etalon system can provide an imaging interferometer that works in four distinct modes: as a spectro-polarimeter, a filter-vector magnetograph, an intermediate-band imager, and broadband high-resolution imager. Specific dual and triple etalon configurations are described that provide a spectrographic passband of 2.0-3.5 micron and reduce parasitic light levels to 10(exp -4) as required for precise polarization measurement, e.g., Zeeman measurements of magnetic sensitive lines. A TESOS-like (Telecentric Etalon SOlar Spectrometer) triple etalon system provides a spectral purity of 10(exp -5). The triple designs have the advantage of reducing the finesse requirement on each etalon; allow the use of more stable blocking filters, and have very high spectral purity. A dual-etalon double-pass (Cavallini-like) system can provide a competing configuration. Such a dual-etalon design can provide high contrast. The selection of the final focal plane instrument will depend on a trade-off between an ideal instrument and practical reality. The trade study will include the number of etalons, their aperture sizes, complexities of the optical train, number of blocking filters, configuration of the electronic control system, computer interfaces, temperature controllers, etalon controllers, and their associated feedback electronics. The heritage of single and multiple etalon systems comes from their use in several observatories, including the Marshall Space Flight Center (MSFC) Solar Observatory, Sacramento Peak Observatory (NSO), and Kiepenheuer-Institut fur Sonnenphysik (KIS, Germany), Mees Solar Observatory (University of Hawaii), and Arcetri Astrophysical Observatory (Italy). The design of the ATST multiple etalon system will benefit from the experience gained at these observatories.

Gary, G. Allen; Balasubramaniam, K. S.; Sigwarth, Michael

2003-01-01

100

Multiple Etalon Systems for the Advanced Technology Solar Telescope  

NASA Technical Reports Server (NTRS)

Multiple etalons systems are discussed that meet the 4-meter NSO/Advance Technology Solar Telescope (http://www.nso.edu/ATST/index.html) instrument and science requirements for a narrow bandpass imaging system. A multiple etalon system can provide an imaging interferometer working in four distinct modes: as a spectro-polarimeter, a filter-vector magnetograph, and a wide-band and broad-band high-resolution imager. Specific dual and triple etalon configurations will be described that provides spectrographic passband of 2.0-3.5nm and reduces parasitic light levels to 1/10000 as required by precise polarization measurement, e.g., Zeeman measurements of magnetic sensitive lines. A TESOS-like triple etalon system provides for spectral purity of 100 thousandths. The triple designs have the advantage of reducing the finesse requirement on each etalon, allowing much more stable blocking filters, and can have very high spectral purity. A dual-etalon double-pass Cavallini-like configuration can provide a competing configuration. This design can provide high contrast with only a double etalon. The selection of the final focal plan instrument will depend on a trade-off of the ideal instrument versus reality, the number of etalons, the aperture of etalons, the number of blocking filters the electronic control system and computer interfaces, the temperature control and controllers for the etalons and the electronics. The use of existing experience should provide significant cost savings. The heritage of use of etalons and multiple etalon systems in solar physics come from a number of observatories, which includes MSFC Solar Observatory (NASA), Sac Peak Observatory (NSO), and Kiepenheuer Institute for Solar Physics (Germany), Mees Solar Observatory (University of Hawaii), and Arcetri Astrophysical Observatory (Italy). The design of the ATST multiple etalon system will reply on the existing experience from these observatories.

Gary, G. Allen; Balasubramaniam, K. S.; Sigwarth, Michael; Six, N. Frank (Technical Monitor)

2002-01-01

101

A large-angle high speed scanner based on electro-optic crystal for Fresnel telescope synthetic aperture imaging ladar  

NASA Astrophysics Data System (ADS)

The cross-orbit scanning is very important for Fresnel telescope synthetic aperture imaging ladar system. This paper presents a design of large-angle high speed scanner based on electro-optic crystal for the cross-orbit scanning in Fresnel telescope synthetic aperture imaging ladar system. The designed scanner is based on the space-charge-controlled EO effect in KTN. In the experiment the crystal temperature should be kept a little higher above Tc to obtain a large EO effect and the polarization of the laser beam should be parallel to the direction of the driving electric field. Compared with other conventional EO crystal scanner, the new scanner can greatly improve the scanner angle by several times when maintains high speed and accuracy, which will have a great potential for cross-orbit scanning applications in Fresnel telescope synthetic aperture imaging ladar system.

Xu, Jun; Zhi, Ya'nan; Wang, Xuping; Sun, Jianfeng; Zhou, Yu; Dai, Enwen; Liu, Liren

2012-10-01

102

ProtoEXIST: advanced prototype CZT coded aperture telescopes for EXIST  

NASA Astrophysics Data System (ADS)

ProtoEXIST1 is a pathfinder for the EXIST-HET, a coded aperture hard X-ray telescope with a 4.5 m2 CZT detector plane a 90x70 degree field of view to be flown as the primary instrument on the EXIST mission and is intended to monitor the full sky every 3 h in an effort to locate GRBs and other high energy transients. ProtoEXIST1 consists of a 256 cm2 tiled CZT detector plane containing 4096 pixels composed of an 8x8 array of individual 1.95 cm x 1.95 cm x 0.5 cm CZT detector modules each with a 8 x 8 pixilated anode configured as a coded aperture telescope with a fully coded 10° x 10° field of view employing passive side shielding and an active CsI anti-coincidence rear shield, recently completed its maiden flight out of Ft. Sumner, NM on the 9th of October 2009. During the duration of its 6 hour flight on-board calibration of the detector plane was carried out utilizing a single tagged 198.8 nCi Am-241 source along with the simultaneous measurement of the background spectrum and an observation of Cygnus X-1. Here we recount the events of the flight and report on the detector performance in a near space environment. We also briefly discuss ProtoEXIST2: the next stage of detector development which employs the NuSTAR ASIC enabling finer (32×32) anode pixilation. When completed ProtoEXIST2 will consist of a 256 cm2 tiled array and be flown simultaneously with the ProtoEXIST1 telescope.

Allen, Branden; Hong, Jaesub; Grindlay, Josh; Barthelmy, Scott D.; Baker, Robert G.; Gehrels, Neil A.; Garson, Trey; Krawczynski, Henric S.; Cook, Walter R.; Harrison, Fiona A.; Apple, Jeffrey A.; Ramsey, Brian D.

2010-07-01

103

Solar synoptic telescope. Characteristics, possibilities, and limits of design  

NASA Astrophysics Data System (ADS)

A rapid evolution of electronics and information technologies makes it possible to use new original designs of synoptic telescopes for solar observations, to increase the demands on their functions, and to fully automate the observation. However, there are hardware and software limits that strongly influence the working capabilities of synoptic telescopes. In this contribution, we analyze relationships between the synoptic telescope's characteristics, the parameters of image digitization, the control, the achievable degree of automation of observations, and the possibilities to implement functions connected with the solar activity monitoring and image archiving. The principles listed above serve as a basis for the design study of the Auxiliary Full-Disc Telescope for the European Solar Telescope (EST), a pan-European project of a large 4-meter solar telescope.

Klva?a, M.; Sobotka, M.; Švanda, M.

2011-10-01

104

Advanced Technology Large-Aperture Space Telescope: Science Drivers and Technology Developments  

NASA Technical Reports Server (NTRS)

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8- to 16-m ultraviolet optical near Infrared space observatory for launch in the 2025 to 2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including: Is there life elsewhere in the Galaxy? We present a range of science drivers and the resulting performance requirements for ATLAST (8- to 16-marcsec angular resolution, diffraction limited imaging at 0.5 micron wavelength, minimum collecting area of 45 sq m, high sensitivity to light wavelengths from 0.1 to 2.4 micron, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to that of current generation observatory-class space missions.

Postman, Marc; Brown, Tom; Sembach, Kenneth; Glavallsco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Phillip; Tumlinson, Jason; Mountain, Matt; Soummer, Remi; Hyde, Tupper

2012-01-01

105

High Contrast Phase Occulted Visible Nulling Coronagraph for Arbitrary Telescope Apertures  

NASA Astrophysics Data System (ADS)

The phase-occulted visible nulling coronagraph is a new and scientifically high payoff approach to exoplanet coronagraphy. It is based on using constructive and destructive interference from a modified Mach-Zehnder interferometer, aka a muller. It uses a single interferometer to achieve theta to the 4 power or higher nulling such that on-axis starlight is ejected through the wavefront control channel, aka bright output channel, and off-axis planet light exits the science channel. The higher order dark hole is achieved by varying a small amount the plate scale difference between the two arms of the nuller. The shape of this plate scale can be controlled in 3 different ways such that the high contrast imaging is in principle achieved broadband and for both polarizations simultaneously and it is independent of the telescope aperture shape. Additionally it has a novel wavefront control system to be discussed.

Lyon, Richard; Clampin, M.

2014-01-01

106

THE BALLOON-BORNE LARGE APERTURE SUBMILLIMETER TELESCOPE (BLAST) 2006: CALIBRATION AND FLIGHT PERFORMANCE  

SciTech Connect

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 250 hr flight over Antarctica in 2006 December (BLAST06). As part of the calibration and pointing procedures, the red hypergiant star VY CMa was observed and used as the primary calibrator. Details of the overall BLAST06 calibration procedure are discussed. The 1sigma uncertainty on the absolute calibration is accurate to 9.5%, 8.7%, and 9.2% at the 250, 350, and 500 mum bands, respectively. The errors are highly correlated between bands resulting in much lower errors for the derived shape of the 250-500 mum continuum. The overall pointing error is < 5'' rms for the 36'', 42'', and 60'' beams. The performance of optics and pointing systems is discussed.

Truch, Matthew D. P.; Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip; Moncelsi, Lorenzo; Pascale, Enzo [Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, CF24 3AA (United Kingdom); Bock, James J. [Jet Propulsion Laboratory, Pasadena, CA 91109-8099 (United States); Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Hughes, David H. [Instituto Nacional de AstrofIsica Optica y Electronica (INAOE), Aptdo. Postal 51 y 72000 Puebla (Mexico); Martin, Peter G. [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Netterfield, C. Barth [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Olmi, Luca [Physics Department, University of Puerto Rico, Rio Piedras Campus, Box 23343, UPR Station, San Juan (Puerto Rico); Patanchon, Guillaume, E-mail: matthew@truch.ne [Universite Paris Diderot, Laboratoire APC, 10 rue Alice Domon et Leonie Duquet 75205 Paris (France)

2009-12-20

107

Thermal design and performance of the balloon-borne large aperture submillimeter telescope for polarimetry BLASTPol  

NASA Astrophysics Data System (ADS)

We present the thermal model of the Balloon-borne Large-Aperture Submillimeter Telescope for Polarimetry (BLASTPol). This instrument was successfully own in two circumpolar flights from McMurdo, Antarctica in 2010 and 2012. During these two flights, BLASTPol obtained unprecedented information about the magnetic field in molecular clouds through the measurement of the polarized thermal emission of interstellar dust grains. The thermal design of the experiment addresses the stability and control of the payload necessary for this kind of measurement. We describe the thermal modeling of the payload including the sun-shielding strategy. We present the in-flight thermal performance of the instrument and compare the predictions of the model with the temperatures registered during the flight. We describe the difficulties of modeling the thermal behavior of the balloon-borne platform and establish landmarks that can be used in the design of future balloon-borne instruments.

Soler, J. D.; Ade, P. A. R.; Angilč, F. E.; Benton, S. J.; Devlin, M. J.; Dober, B.; Fissel, L. M.; Fukui, Y.; Galitzki, N.; Gandilo, N. N.; Klein, J.; Korotkov, A. L.; Matthews, T. G.; Moncelsi, L.; Mroczkowski, A.; Netterfield, C. B.; Novak, G.; Nutter, D.; Pascale, E.; Poidevin, F.; Savini, G.; Scott, D.; Shariff, Jamil A.; Thomas, N. E.; Truch, M. D.; Tucker, C. E.; Tucker, G. S.; Ward-Thompson, D.

2014-07-01

108

Advanced Technology Large-Aperture Space Telescope: science drivers and technology developments  

NASA Astrophysics Data System (ADS)

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8- to 16-m ultraviolet optical near infrared space observatory for launch in the 2025 to 2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including: Is there life elsewhere in the Galaxy? We present a range of science drivers and the resulting performance requirements for ATLAST (8- to 16-marcsec angular resolution, diffraction limited imaging at 0.5-?m wavelength, minimum collecting area of 45 m2, high sensitivity to light wavelengths from 0.1 to 2.4 ?m, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to that of current generation observatory-class space missions.

Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Michael Rich, R.; Phillip Stahl, H.; Tumlinson, Jason; Mountain, Matt; Soummer, Rémi; Hyde, Tupper

2012-01-01

109

Stability studies of Solar Optical Telescope dynamics  

NASA Technical Reports Server (NTRS)

The Solar Optical Telescope (SOT) is designed to operate as an attached payload mounted on the Instrument Pointing System (IPS) in the cargo bay of the Shuttle Orbiter. Pointing and control of SOT is accomplished by an active Articulated Primary Mirror (APM), an active Tertiary Mirror (TM), an elaborate set of optical sensors, electromechanical actuators and programmable controllers. The structural interactions of this complex control system are significant factors in the stability of the SOT. The preliminary stability study results of the SOT dynamical system are presented. Structural transfer functions obtained from the NASTRAN model of the structure were used. These studies apply to a single degree of freedom (elevation). Fully integrated model studies will be conducted in the future.

Gullapalli, Sarma N.; Pal, Parimal K.; Ruthven, Gregory P.

1987-01-01

110

Solar Sail - Fresnel Zone Plate Lens for a Large Space Based Telescope  

SciTech Connect

A Fresnel zone plate lens made with solar sail material could be used as the primary optic for a very large aperture telescope on deep space probes propelled by solar sails. The large aperture telescope capability could enable significant science on fly-by missions to the asteroids, Pluto, Kuiper belt or the tort cloud and could also enable meaningful interstellar fly-by missions for laser propelled sails. This type of lens may also have some potential for laser communications and as a solar concentrator. The techniques for fabrication of meter size and larger Fresnel phase plate optics are under development at LLNL, and we are extending this technology to amplitude zone plates made from sail materials. Corrector optics to greatly extend the bandwidth of these Fresnel optics will be demonstrated in the future. This novel telescope concept will require new understanding of the fabrication, deployment and control of gossamer space structures. It will also require new materials technology for fabricating these optics and understanding their long term stability in a space environment.

Early, J T

2002-02-13

111

Analysis of adaptive optics control for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

Large aperture solar telescopes, such as the 4 meter aperture Advanced Technology Solar Telescope (ATST), depend on high order adaptive optics (AO) to achieve the telescope's diffraction limited resolution. The AO system not only corrects incoming distortions introduced by atmospheric turbulence, its performance also plays a critical role for the operation of other subsystems and affects the results obtained by downstream scientific instrumentation. For this reason, robust and optimal operation of the AO system is vital to maximize the scientific output of ATST. In order to optimize performance, we evaluate different strategies to obtain the control matrix of the AO system. The dependency of AO performance on various control parameters, such as different system calibration and reconstruction schemes, is analyzed using an AO simulation tool. The AO simulation tool provides a realistic solar AO system simulation and allows a detailed evaluation of the performance achieved by different calibration and reconstruction methods. The results of this study will guide the optimization of the AO system during design and operations.

Marino, Jose; Wöger, Friedrich; Rimmele, Thomas

2010-07-01

112

The Balloon-borne Large-Aperture Submillimeter Telescope for Polarization: BLAST-pol  

E-print Network

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a sub-orbital experiment designed to study the process of star formation in local galaxies (including the Milky Way) and in galaxies at cosmological distances. Using a 2-m Cassegrain telescope, BLAST images the sky onto a focal plane, which consists of 270 bolometric detectors split between three arrays, observing simultaneously in 30% wide bands, centered at 250, 350, and 500 microns. The diffraction-limited optical system provides a resolution of 30" at 250 microns. The pointing system enables raster-like scans with a positional accuracy of ~30", reconstructed to better than 5" rms in post-flight analysis. BLAST had two successful flights, from the Arctic in 2005, and from Antarctica in 2006, which provided the first high-resolution and large-area (~0.8-200 deg^2) submillimeter surveys at these wavelengths. As a pathfinder for the SPIRE instrument on Herschel, BLAST shares with the ESA satellite similar focal plane technology and scientific motivation. A third flight in 2009 will see the instrument modified to be polarization-sensitive (BLAST-Pol). With its unprecedented mapping speed and resolution, BLAST-Pol will provide insights into Galactic star-forming nurseries, and give the necessary link between the larger, coarse resolution surveys and the narrow, resolved observations of star-forming structures from space and ground based instruments being commissioned in the next 5 years.

G. Marsden; P. A. R. Ade; S. Benton; J. J. Bock; E. L. Chapin; J. Chung; M. J. Devlin; S. Dicker; L. Fissel; M. Griffin; J. O. Gundersen; M. Halpern; P. C. Hargrave; D. H. Hughes; J. Klein; A. Korotkov; C. J. MacTavish; P. G. Martin; T. G. Martin; T. G. Matthews; P. Mauskopf; L. Moncelsi; C. B. Netterfield; G. Novak; E. Pascale; L. Olmi; G. Patanchon; M. Rex; G. Savini; D. Scott; C. Semisch; N. Thomas; M. D. P. Truch; C. Tucker; G. S. Tucker; M. P. Viero; D. Ward-Thompson; D. V. Wiebe

2008-05-28

113

Narrow-band Imager for Multi-Application Solar Telescope (MAST) at Udaipur Solar Observatory  

NASA Astrophysics Data System (ADS)

Multi-Application Solar Telescope (MAST) is an off-axis Gregorian solar telescope of 50 cm clear aperture installed at the lake site of Udaipur solar observatory (USO). A narrow band imager is being developed for near simultaneous observations of the solar atmosphere at different heights. The heart of the system is two Fabry-Perot (FP) etalons working in tandem. The substrate of the etalons is made of Lithium Niobate electro-optic crystal. The filter is tuned by changing the refractive index of the crystal with the application of the voltage. It is important to know the voltage required per unit wavelength shift to tune the system for different wavelength regions for near simultaneous observations. A littrow spectrograph was set up to calibrate the FP etalons. The achieved spectral resolution with the spectrograph at 6173 Ĺ is 35 mĹ. Calibration is carried-out for the Fe I 6173 Ĺ, H-alpha 6563 Ĺ and Ca K 8542 Ĺ. Free spectral range (FSR) obtained for FP1 and FP2 in tandem for 6173 Ĺ is 6.7Ĺ and 150 mĹ respectively. Voltage range of the system allows us to scan the entire line profile of 6173 in the range of ±220 mĹ with a sampling of 20 mĹ. We also performed temperature tuning and voltage tuning of the system. Similar exercise is performed for other two wavelengths. Here we present the details of the calibration set-up and obtained parameters and first-light results of the system.

Raja Bayanna, A.; Mathew, Shibu K.; Venkatakrishnan, Parameswaran; Srivastava, Nandita

2013-04-01

114

Daniel K. Inouye Solar Telescope system safety  

NASA Astrophysics Data System (ADS)

System safety for the Daniel K. Inouye Solar Telescope (DKIST) is the joint responsibility of a Maui-based safety team and the Tucson-based systems engineering group. The DKIST project is committed to the philosophy of "Safety by Design". To that end the project has implemented an aggressive hazard analysis, risk assessment, and mitigation system. It was initially based on MIL-STD-882D, but has since been augmented in a way that lends itself to direct application to the design of our Global Interlock System (GIS). This was accomplished by adopting the American National Standard for Industrial Robots and Robot Systems (ANSI/RIA R15.06) for all identified hazards that involve potential injury to personnel. In this paper we describe the details of our augmented hazard analysis system and its use by the project. Since most of the major hardware for the DKIST (e.g., the enclosure, and telescope mount assembly) has been designed and is being constructed by external contractors, the DKIST project has required our contractors to perform a uniform hazard analysis of their designs using our methods. This paper also describes the review and follow-up process implemented by the project that is applied to both internal and external subsystem designs. Our own weekly hazard analysis team meetings have now largely turned to system-level hazards and hazards related to specific tasks that will be encountered during integration, test, and commissioning and maintenance operations. Finally we discuss a few lessons learned, describing things we might do differently if we were starting over today.

Hubbard, Robert P.; Bulau, Scott E.; Shimko, Steve; Williams, Timothy R.

2014-08-01

115

The wavefront correction system for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

An important part of a large solar telescope is the ability to correct, in real time, optical alignment errors caused by gravitational bending of the telescope structure and wavefront errors caused by atmospheric seeing. The National Solar Observatory is currently designing the 4 meter Advanced Technology Solar Telescope (ATST). The ATST wavefront correction system, described in this paper, will incorporate a number of interacting wavefront control systems to provide diffraction limited imaging performance. We will describe these systems and summarize the interaction between the various sub-systems and present results of performance modeling.

Rimmele, T.; Richards, K.; Roche, J. M.; Hegwer, S. L.; Hubbard, R. P.; Hansen, E. R.; Goodrich, B.; Upton, R. S.

2006-06-01

116

Daniel K. Inouye Solar Telescope: integration testing and commissioning planning  

NASA Astrophysics Data System (ADS)

The Daniel K. Inouye Solar Telescope (DKIST), formerly the Advanced Technology Solar Telescope (ATST), has been in its construction phase since 2010, anticipating the onset of the integration, test, and commissioning (IT&C) phase late in 2016, and the commencement of science verification in early 2019. In this paper we describe the planning of the Integration, Testing and Commissioning (IT&C) phase of the project.

Craig, Simon; Bulau, Scott E.; Gonzales, Kerry; Hansen, Eric; Goodrich, Bret; Hubbard, Robert P.; Johansson, Eric; Liang, Chen; Kneale, Ruth A.; McBride, William; Sekulic, Predrag; Williams, Timothy R.

2014-08-01

117

8 Meter Advanced Technology Large-Aperture Space Telescope (ATLAST-8m)  

NASA Technical Reports Server (NTRS)

ATLAST-8m (Advanced Technology Large Aperture Space Telescope) is a proposed 8-meter monolithic UV/optical/NIR space observatory (wavelength range 110 to 2500 nm) to be placed in orbit at Sun-Earth L2 by NASA's planned Ares V heavy lift vehicle. Given its very high angular resolution (15 mas @ 500 nm), sensitivity and performance stability, ATLAST-8m is capable of achieving breakthroughs in a broad range of astrophysics including: Is there life elsewhere in the Galaxy? An 8-meter UVOIR observatory has the performance required to detect habitability (H2O, atmospheric column density) and biosignatures (O2, O3, CH4) in terrestrial exoplanet atmospheres, to reveal the underlying physics that drives star formation, and to trace the complex interactions between dark matter, galaxies, and intergalactic medium. The ATLAST Astrophysics Strategic Mission Concept Study developed a detailed point design for an 8-m monolithic observatory including optical design; structural design/analysis including primary mirror support structure, sun shade and secondary mirror support structure; thermal analysis; spacecraft including structure, propulsion, GN&C, avionics, power systems and reaction wheels; mass and power budgets; and system cost. The results of which were submitted by invitation to NRC's 2010 Astronomy & Astrophysics Decadal Survey.

Stahl, H. Philip

2010-01-01

118

Hybrid Electrostatic/Flextensional Mirror for Lightweight, Large-Aperture, and Cryogenic Space Telescopes  

NASA Technical Reports Server (NTRS)

A lightweight, cryogenically capable, scalable, deformable mirror has been developed for space telescopes. This innovation makes use of polymer-based membrane mirror technology to enable large-aperture mirrors that can be easily launched and deployed. The key component of this innovation is a lightweight, large-stroke, cryogenic actuator array that combines the high degree of mirror figure control needed with a large actuator influence function. The latter aspect of the innovation allows membrane mirror figure correction with a relatively low actuator density, preserving the lightweight attributes of the system. The principal components of this technology are lightweight, low-profile, high-stroke, cryogenic-capable piezoelectric actuators based on PMN-PT (piezoelectric lead magnesium niobate-lead titanate) single-crystal configured in a flextensional actuator format; high-quality, low-thermal-expansion polymer membrane mirror materials developed by NeXolve; and electrostatic coupling between the membrane mirror and the piezoelectric actuator assembly to minimize problems such as actuator print-through.

Patrick, Brian; Moore, James; Hackenberger, Wesley; Jiang, Xiaoning

2013-01-01

119

Receiver for solar energy collector having improved aperture aspect  

DOEpatents

A secondary concentrator for use in receiver systems for linear focusing primary concentrators is provided with reflector wings at each end. The wings increase the capture of light rays reflected from areas adjacent the rim of a primary concentrator, increasing the apparent aperture size of the absorber as viewed from the rim of the primary concentrator. The length, tilt, and curvature of the wing reflectors can be adjusted to provide an absorber having a desired aperture aspect.

McIntire, William R. (Downers Grove, IL)

1984-01-01

120

A retrospective of the GREGOR solar telescope in scientific literature  

NASA Astrophysics Data System (ADS)

In this review, we look back upon the literature, which had the GREGOR solar telescope project as its subject including science cases, telescope subsystems, and post-focus instruments. The articles date back to the year 2000, when the initial concepts for a new solar telescope on Tenerife were first presented at scientific meetings. This comprehensive bibliography contains literature until the year 2012, i.e., the final stages of commissioning and science verification. Taking stock of the various publications in peer-reviewed journals and conference proceedings also provides the ``historical'' context for the reference articles in this special issue of Astronomische Nachrichten/Astronomical Notes.

Denker, C.; von der Lühe, O.; Feller, A.; Arlt, K.; Balthasar, H.; Bauer, S.-M.; Bello González, N.; Berkefeld, Th.; Caligari, P.; Collados, M.; Fischer, A.; Granzer, T.; Hahn, T.; Halbgewachs, C.; Heidecke, F.; Hofmann, A.; Kentischer, T.; Klva{?a, M.; Kneer, F.; Lagg, A.; Nicklas, H.; Popow, E.; Puschmann, K. G.; Rendtel, J.; Schmidt, D.; Schmidt, W.; Sobotka, M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier, K. G.; Volkmer, R.; Waldmann, T.; Wiehr, E.; Wittmann, A. D.; Woche, M.

2012-11-01

121

Polarization Calibration of the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) will be the World's largest solar polarimeter with a number of polarimetric instruments simultaneously sharing the ATST light beam. Polarization calibration requires determination of the polarization properties of the telescope optics that are shared by all instruments and the polarization response of each instrument. Hundreds of parameters are required to fully specify the telescope optics but by grouping successive optical elements separated at the Gregorian focus, the elevation rotation, and the Coudé - azimuth rotation and performing calibrations over the course of a day, it is possible to infer the polarization properties of each of the groups, and the instruments themselves with many fewer parameters.

Elmore, D. F.

2014-10-01

122

Polarization Model for the New Vacuum Solar Telescope  

NASA Astrophysics Data System (ADS)

It is essential to properly calibrate the instrumental polarization for solar telescopes, if one wants to achieve a high spectro-polarimetric accuracy. Model fitting is an efficient calibration method for telescopes with alt-azimuth mount. We have constructed an ideal model for the New Vacuum Solar Telescope (NVST) which describes its pupil and time-dependent polarization properties. An integration of polarization ray-tracing in pupil is implemented for solving the net polarization of main optics. The time and season-dependent polarization of the Coudé optics is calculated based on the NVST geometry and complex refractive index of ideal Al film.

Yuan, S.

2014-10-01

123

Development of large aperture cooled telescopes for the space infrared telescope for cosmology and astrophysics (SPICA) mission  

Microsoft Academic Search

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) mission is the third Japanese astronomical infrared satellite project of a 3.5m cooled telescope optimized for mid- to far-infrared observations, following the Infrared Telescope in Space (IRTS) and the ASTRO-F missions. It will employ mechanical coolers and an efficient radiative cooling system, which allow us to have a cooled (4.5K) telescope

Takashi Onaka; Hidehiro Kaneda; Keigo Enya; Takao Nakagawa; Hiroshi Murakiami; Hideo Matsuhara; Hirokazu Kataza

2005-01-01

124

Optimum aperture size and operating temperature of a solar cavity-receiver  

Microsoft Academic Search

For solar cavity-receivers operating at high temperatures, the optimum aperture size results from a compromise between maximizing radiation capture and minimizing radiation losses. When the absorbed solar energy is utilized as high temperature process heat, the energy conversion efficiency can be represented as the product of the energy absorption efficiency and the Carnot efficiency. The authors describe a simple, semiempirical

A. Steinfeld; M. Schubnell

1993-01-01

125

Defining A Risk Analysis Strategy for Exo-Earth Yields from a Future Large Aperture UVOIR Space Telescope  

NASA Astrophysics Data System (ADS)

The discovery and characterization of Earth-like planets around Sun-like stars using high-contrast imaging is a critical science metric for constraining the requirements on the next-generation large UVOIR space telescope. The dominant driver for the observatory architecture, cost and schedule is the telescope aperture size. Therefore it is important to provide as much constraint as possible on the required aperture size early in the design and planning process.An estimate of the detection yield for Earth-like planets can be calculated using a Monte Carlo simulation of a design reference mission (DRM), allowing the exploration of a variety of mission design and astrophysical parameters. We have developed such a code (Stark et al. 2014); it optimizes the target list and exposure times to maximize mission yield for a specific set of mission parameters. However, many of the important astrophysical quantities and future technical capabilities that feed into these parameters are not well constrained. This leads to a large uncertainty in the final mission architecture needed to achieve a specific exo-Earth yield.In this presentation we discuss the various physical and technological parameters that go into the DRM simulations, and the associated uncertainties based on the current state of research. We then present a strategy for a three-tiered risk assessment using these uncertainties, and conclude with a discussion of the current range in telescope aperture size associated with each risk level.

Mandell, Avi; Stark, Christopher C.; Roberge, Aki; Domagal-Goldman, Shawn; Stapelfeldt, Karl R.; Robinson, Tyler

2015-01-01

126

Photographic films for the Multi-Spectral Solar Telescope Array  

NASA Astrophysics Data System (ADS)

The rocketborne Multi-Spectral Solar Telescope Array (MSSTA) uses an array of Ritchey-Chretien, Cassegrain, and Herschelian telescopes to produce ultrahigh-resolution full-disk images of the sun within the soft X-ray, EUV, and FUV ranges. Such imaging of the solar disk and corona out to several solar radii placed great demands on the MSSTA's data storage capabilities; in addition, its photographic films required very low outgassing rates. Results are presented from calibration tests conducted on the MSSTA's emulsions, based on measurements at NIST's synchrotron facility.

Hoover, Richard B.; Walker, Arthur B. C., Jr.; Deforest, Craig E.; Allen, Maxwell J.; Lindblom, Joakim F.; Gilliam, Lou; November, Larry; Brown, Todd; Dewan, Clyde A.

1992-01-01

127

The Advanced Technology Solar Telescope (ATST) project: a construction update  

NASA Astrophysics Data System (ADS)

The 4m Advance Technology Solar Telescope (ATST) will be the world's leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. The project has entered its construction phase. Major subsystems have been contracted, designs are complete, and fabrication has started. As its highest priority science driver ATST shall provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. A high order adaptive optics system delivers a corrected beam to the initial set of state-of-the-art, facility class instrumentation located in the Coudé laboratory facility. The initial set of five first generation instruments consists of imagers and spectro-polarimeters. Development and construction of a four-meter solar telescope presents many technical challenges, including thermal control of the enclosure, telescope structure and optics and wavefront control. A brief overview of the science goals and observational requirements of the ATST will be given, followed by a summary of the status of the telescope, its instrumentation, and the construction of the facility.

Warner, Mark; McMullin, Joseph; Rimmele, Thomas; Berger, Tom

2013-09-01

128

Solar System Science with the James Webb Space Telescope  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) will succeed the Hubble Space Telescope as NASA’s premier space-based platform for observational astronomy. This 6.5-meter telescope, which is optimized for observations in the near and mid infrared, will be equipped with four state-of-the-art imaging, spectroscopic, and coronagraphic instruments. These instruments, along with the telescope’s moving target capabilities, will enable the infrared study of solar system objects with unprecedented detail (see companion presentation by Sonneborn et al.). This poster features highlights for planetary science applications, extracted from a white paper in preparation. We present a number of hypothetical solar system observations as a means of demonstrating potential planetary science observing scenarios; the list of applications discussed here is far from comprehensive. The goal of this poster and the subsequent white paper is to stimulate discussion and encourage participation in JWST planning among members of the planetary science community, and to encourage feedback to the JWST Project on any desired observing capabilities, data products, and analysis procedures that would enhance the use of JWST for solar system studies. The upcoming white paper updates and supersedes the solar system white paper published by the JWST Project in 2010 (Lunine et al., 2010), and is based in part on JWST events held at the 2012 DPS, the 2013 LPSC meeting, and this DPS (JWST Town Hall, Thursday, 10 October 2013, 12-1 pm).

Hammel, Heidi B.; Norwood, J.; Chanover, N.; Hines, D. C.; Stansberry, J.; Lunine, J. I.; Tiscareno, M. S.; Milam, S. N.; Sonneborn, G.; Brown, M.

2013-10-01

129

Daniel K. Inouye Solar Telescope systems engineering update  

NASA Astrophysics Data System (ADS)

The Daniel K. Inouye Solar Telescope (DKIST), formerly the Advanced Technology Solar Telescope (ATST), has been in its construction phase since 2010, anticipating the onset of integration, test, and commissioning (IT and C) phase late in 2016, and the commencement of science verification in early 2019. In this paper we describe the role of Systems Engineering during these final phases of the project, and present some of the tools, techniques, and methods in use for these purposes. The paper concludes with a brief discussion of lessons learned so far including things we might do differently next time.

Craig, Simon; Hansen, Eric; Hubbard, Robert P.; Kneale, Ruth

2014-08-01

130

STATISTICAL DISTRIBUTION OF SIZE AND LIFETIME OF BRIGHT POINTS OBSERVED WITH THE NEW SOLAR TELESCOPE  

SciTech Connect

We present results of 2 hr non-interrupted observations of solar granulation obtained under excellent seeing conditions with the largest aperture ground-based solar telescope-the New Solar Telescope (NST)-of Big Bear Solar Observatory. Observations were performed with adaptive optics correction using a broadband TiO filter in the 705.7 nm spectral line with a time cadence of 10 s and a pixel size of 0.''0375. Photospheric bright points (BPs) were detected and tracked. We find that the BPs detected in NST images are cospatial with those visible in Hinode/SOT G-band images. In cases where Hinode/SOT detects one large BP, NST detects several separated BPs. Extended filigree features are clearly fragmented into separate BPs in NST images. The distribution function of BP sizes extends to the diffraction limit of NST (77 km) without saturation and corresponds to a log-normal distribution. The lifetime distribution function follows a log-normal approximation for all BPs with lifetime exceeding 100 s. A majority of BPs are transient events reflecting the strong dynamics of the quiet Sun: 98.6% of BPs live less than 120 s. The longest registered lifetime was 44 minutes. The size and maximum intensity of BPs were found to be proportional to their lifetimes.

Abramenko, Valentyna; Yurchyshyn, Vasyl; Goode, Philip; Kilcik, Ali [Big Bear Solar Observatory, 40386 N. Shore Lane, Big Bear City, CA 92314 (United States)

2010-12-10

131

Prototype Spectro-Polarimeter for the India's National Large Solar Telescope  

NASA Astrophysics Data System (ADS)

India's National Large Solar Telescope (NLST) of two meter aperture size is proposed to be set up in Ladakh region of Himalayas at a height of around 4300 meters. A high resolution spectrograph along with a polarimeter is planned as one of the backend instruments for NLST. Prototype development of the NLST Spectro-Polarimeter (SP) is proposed to be designed and developed for usage at the back focal plane of the Multi-Application Solar Telescope (MAST) recently installed at the Udaipur Solar Observatory. Design of the prototype SP is discussed in detail along with the scientific goals. The SP is designed to be operated in three wavelengths to observe photospheric and chromospheric layers of the solar atmosphere simultaneously. Vector magnetic fields will be calculated in these layers. High resolution of the designed SP will provide accurate estimates of velocities. Highly resolved polarized line profiles will allow us to obtain the height variation of vector magnetic fields when used along with suitable inversion codes (like SPINOR or SIR).

Elayavalli Rangarajan, Komandur; Sankarasubramanian, Kasiviswanathan; Srivastava, Nandita; Venkatakrishnan, Parameswaran; Mathew, Shibu; Bayanna, Raja; Hasan, Sirajul; Prabhu, Kesavan

2013-04-01

132

The Advanced Technology Solar Telescope Construction Status Report  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) will provide observing capabilities in the visible through infrared wavelengths with unprecedented resolution and sensitivity. Designed to study solar magnetism that controls the solar wind, flares, CMEs and variability in the Sun's output, the ATST will be capable of detecting and spatially resolving the fundamental astrophysical processes at their intrinsic scales throughout the solar atmosphere. The 4-m class facility is currently under construction in Maui, HI on the Haleakala Observatories site with a scheduled completion of July 2019. Since the start of site construction in December of 2012, significant progress has been made toward the development of the observatory buildings (excavation, foundations, working towards the steel erection). In addition, off-site, the major subsystems of the telescope have been contracted, designs are complete and fabrication is underway. We review the science drivers, design details, technical challenges, and provide a construction status update on the subsystems and their integration.

McMullin, Joseph P.; Rimmele, T. R.; Warner, M.; Berger, T.; Keil, S. L.

2013-07-01

133

The National Large Solar Telescope (NLST) of India  

NASA Astrophysics Data System (ADS)

The Indian National Large Solar Telescope (NLST) will be a state-of-the-art 2-m class telescope for carrying out high-resolution studies in the solar atmosphere. Recent numerical simulations suggest that crucial physical processes like vortex flow, dissipation of magnetic fields and the generation of MHD waves can occur efficiently over length scales of tens of kilometers. Current telescopes are unable to resolve solar feature to this level at visible wavelengths. NLST will not only achieve good spatial resolution, but will also have a high photon throughput in order to carry out spectropolarimetric observations to accurately measure vector magnetic fields in the solar atmosphere with a good signal to noise ratio. The main science goals of NLST include: a) Magnetic field generation and the solar cycle; b) Dynamics of magnetized regions; c) Helioseismology; d) Long term variability; e) Energetic phenomena and Activity; and f) Night time astronomy. The optical design of the telescope is optimized for high optical throughput and uses a minimum number of optical elements. A high order adaptive optics system is integrated as part of the design that works with a modest Fried's parameter of 7-cm to give diffraction limited performance. The telescope will be equipped with a suite of post-focus instruments including a high resolution spectrograph and a polarimeter. NLST will also be used for carrying out stellar observations during the night. The mechanical design of the telescope, building, and the innovative dome takes advantage of the natural air flush which will help to keep the open telescope in temperature equilibrium. Critical to the successful implementation of NLST is the selection of a site with optimum atmospheric properties, such as the number of sunshine hours and good "seeing" over long periods. A site characterization programme carried over several years has established the existence of suitable sites in the Ladakh region. After its completion, currently planned for 2016, NLST will fill a gap in longitude between the major solar facilities in the world and will be for some years the largest solar telescope in the world.

Hasan, S. S.

2012-12-01

134

Advanced electrostatically clean solar array panel design using reflective aperture grids  

Microsoft Academic Search

An improved design for an electrostatically clean solar array (ECSA) is described. The baseline ECSA uses a frontside shield with apertures (FSA) to establish a continuously grounded frontside plane, and cover exposed conductors. The improved design adds a tent-shaped reflective cover onto the FSA which collects the energy that would normally be lost in the area covered by the FSA,

T. G. Stern

2002-01-01

135

Solar System observations with the James Webb Space Telescope  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) will succeed the Hubble Space Telescope as NASA's premier space-based platform for observational astronomy. This 6.5-meter telescope, which is optimized for observations in the near and mid infrared, will be equipped with four state-of-the-art instruments, which include imaging, spectroscopy, and coronagraphy. These instruments, along with the telescope's moving target capabilities, will enable the infrared study of solar-system objects with unprecedented detail. This poster features highlights for planetary-science applications, extracted from the recent white paper (Norwood et al., 2014). We present a number of hypothetical solar-system observations as a means of demonstrating potential planetary-science observing scenarios; the list of applications discussed here is far from comprehensive. The goals of this poster and white paper are to stimulate discussion and encourage participation in JWST planning among members of the planetary-science community, and to encourage feedback to the JWST Project on any desired observing capabilities, data products, and analysis procedures that would enhance the use of JWST for solar-system studies. This latest work provides the latest observatory and instrument capabilities and expands upon earlier studies of JWST solar-system opportunities (Lunine et al., 2010).

Milam, S.; Norwood, J.; Hammel, H.; Stansberry, J.; Lunine, J.; Chanover, N.; Hines, D.; Sonneborn, G.; Tiscareno, M.; Brown, M.; Ferruit, P.

2014-07-01

136

Solar System Science with the James Webb Space Telescope  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) will succeed the Hubble Space Telescope as NASA's premier space-based platform for observational astronomy. This 6.5-meter telescope, which is optimized for observations in the near and mid infrared, will be equipped with four state-of-the-art imaging, spectroscopic, and coronagraphic instruments. These instruments, along with the telescope's moving target capabilities, will enable the infrared study of solar system objects with unprecedented detail. This poster features highlights for planetary science applications, extracted from a white paper in preparation. We present a number of hypothetical solar system observations as a means of demonstrating potential planetary science observing scenarios; the list of applications discussed here is far from comprehensive. The goal of this poster and the subsequent white paper is to stimulate discussion and encourage participation in JWST planning among members of the planetary science community, and to encourage feedback to the JWST Project on any desired observing capabilities, data products, and analysis procedures that would enhance the use of JWST for solar system studies. The upcoming white paper updates and supersedes the solar system white paper published by the JWST Project in 2010 (Lunine et al., 2010), and is based in part on JWST events held at the 2012 and 2013 DPS meetings, and the 2013 LPSC meeting.

Norwood, J.; Hammel, H. B.; Milam, S.; Lunine, J. I.; Chanover, N.; Stansberry, J.; Hines, D. C.; Sonneborn, G.; Brown, M. E.; Tiscareno, M. S.

2013-12-01

137

Latest results and prospects of the CERN Axion Solar Telescope  

Microsoft Academic Search

The CERN Axion Solar Telescope (CAST) experiment searches for axions from the Sun converted into few keV photons via the inverse Primakoff effect in the high magnetic field of a superconducting Large Hadron Collider (LHC) decommissioned test magnet. After results obtained with vacuum in the magnet pipes (phase I of the experiment) as well as with 4He the collaboration is

I. G. Irastorza; S. Aune; K. Barth; A. Belov; S. Borghi; H. Bräuninger; G. Cantatore; J. M. Carmona; S. A. Cetin; J. I. Collar; T. Dafni; M. Davenport; C. Eleftheriadis; N. Elias; C. Ezer; G. Fanourakis; E. Ferrer-Ribas; P. Friedrich; J. Galán; A. Gardikiotis; E. N. Gazis; T. Geralis; I. Giomataris; S. Gninenko; H. Gómez; E. Gruber; T. Guthörl; R. Hartmann; F. Haug; M. D. Hasinoff; D. H. H. Hoffmann; F. J. Iguaz; J. Jacoby; K. Jakovcic; M. Karuza; K. Königsmann; R. Kotthaus; M. Krcmar; M. Kuster; B. Lakic; J. M. Laurent; A. Liolios; A. Ljubicic; V. Lozza; G. Lutz; G. Luzón; J. Morales; T. Niinikoski; A. Nordt; T. Papaevangelou; M. J. Pivovaroff; G. Raffelt; T. Rashba; H. Riege; A. Rodríguez; M. Rosu; J. Ruz; I. Savvidis; P. S. Silva; S. K. Solanki; R. Soufli; L. Stewart; A. Tomás; M. Tsagri; K. van Bibber; T. Vafeiadis; J. Villar; J. K. Vogel; S. C. Yildiz; K. Zioutas

2011-01-01

138

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLAST-Pol): Instrument and 2010 Science Campaign  

NASA Astrophysics Data System (ADS)

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLAST-Pol) is a 1.8-m telescope that observes polarized dust emission with a resolution of 1'. BLAST-Pol images the sky onto a focal plane that consists of 270 feed-horn coupled bolometers at 250, 350, and 500 microns. In January 2011, BLAST-Pol completed a successful 9.5-day flight over Antarctica. Eight science targets were observed, and a second flight is planned for December 2012. I will give an overview of the instrument performance during the first science campaign and present preliminary maps. BLAST-Pol maps will provide an excellent dataset for studying the role of magnetic fields in star formation.

Gandilo, Natalie; BLAST-Pol Collaboration

2012-01-01

139

Protective telescoping shield for solar concentrator  

NASA Technical Reports Server (NTRS)

An apparatus is described for use with a solar concentrator such as a parabolic dish which concentrates sunlight onto a small opening of a solar receiver, for protecting the receiver in the event of a system failure that could cause concentrated sunlight to damage the receiver. The protective apparatus includes a structure which can be moved to a stowed position where it does not block sunlight, to a deployed position. In this position, the structure forms a tube which substantially completely surrounds an axis connecting the receiver opening to the center of the concentrator at locations between the receiver and the concentrator.

Argoud, M. J.; Walker, W. L.; Butler, L. V. (inventors)

1986-01-01

140

Solar tests of aperture plate materials for solar thermal dish collectors  

NASA Technical Reports Server (NTRS)

If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

Jaffe, L. D.

1984-01-01

141

Solar tests of aperture plate materials for solar thermal dish collectors  

NASA Astrophysics Data System (ADS)

If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluoroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fall apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

Jaffe, L. D.

142

Solar Tests of Aperture Plate Materials for Solar Thermal Dish Collectors  

NASA Technical Reports Server (NTRS)

If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the Sun, motion of the concentrator may stop. As the Sun moves relative to the Earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluoroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fall apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

Jaffe, L. D.

1984-01-01

143

Solar tests of aperture plate materials for solar thermal dish collectors  

NASA Astrophysics Data System (ADS)

If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the Sun, motion of the concentrator may stop. As the Sun moves relative to the Earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluoroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fall apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

Jaffe, L. D.

1984-03-01

144

Solar tests of aperture plate materials for solar thermal dish collectors  

NASA Astrophysics Data System (ADS)

If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

Jaffe, L. D.

1984-11-01

145

Solar tests of aperture plate materials for solar thermal dish collectors  

NASA Technical Reports Server (NTRS)

If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluoroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fall apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

Jaffe, L. D.

1984-01-01

146

G-133: A soft x ray solar telescope  

NASA Technical Reports Server (NTRS)

The GOLDHELOX Project, NASA payload number G-133, is a robotic soft x ray solar telescope designed and built by an organization of undergraduate students. The telescope is designed to observe the sun at a wavelength of 171 to 181 A. Since we require observations free from atmospheric interference, the telescope will be launched in a NASA Get-Away-Special (GAS) canister with a Motorized Door Assembly (MDA). In this paper we primarily discuss the most important elements of the telescope itself. We also elaborate on some of the technical difficulties associated with doing good science in space on a small budget (about $100,000) and mention ways in which controlling the instrument environment has reduced the complexity of the system and thus saved us money.

Williams, Memorie K.; Campbell, Branton; Roming, Peter W. A.; Spute, Mark K.; Moody, J. Ward

1992-01-01

147

G-133: A soft X ray solar telescope  

NASA Astrophysics Data System (ADS)

The GOLDHELOX Project, NASA payload number G-133, is a robotic soft x ray solar telescope designed and built by an organization of undergraduate students. The telescope is designed to observe the sun at a wavelength of 171 to 181 A. Since we require observations free from atmospheric interference, the telescope will be launched in a NASA Get-Away-Special (GAS) canister with a Motorized Door Assembly (MDA). In this paper we primarily discuss the most important elements of the telescope itself. We also elaborate on some of the technical difficulties associated with doing good science in space on a small budget (about $100,000) and mention ways in which controlling the instrument environment has reduced the complexity of the system and thus saved us money.

Williams, Memorie K.; Campbell, Branton; Roming, Peter W. A.; Spute, Mark K.; Moody, J. Ward

1992-10-01

148

The science case and data processing strategy for the Thinned Aperture Light Collector (TALC): a project for a 20m far-infrared space telescope  

NASA Astrophysics Data System (ADS)

The future of far-infrared observations rests on our capacity to reach sub-arcsecond angular resolution around 100 ?m, in order to achieve a significant advance with respect to our current capabilities. Furthermore, by reaching this angular resolution we can bridge the gap between capacities offered by the JWST in the near infrared and those allowed by ALMA in the submillimeter, and thus benefit from similar resolving capacities over the whole wavelength range where interstellar dust radiates and where key atomic and molecular transitions are found. In an accompanying paper,1 we present a concept of a deployable annular telescope, named TALC for Thinned Aperture Light Collector, reaching 20m in diameter. Being annular, this telescope features a main beam width equivalent to that of a 27m telescope, i.e. an angular resolution of 0.92" at 100 ?m. In this paper we focus on the science case of such a telescope as well on the aspects of unconventional data processing that come with this unconventional optical configuration. The principal science cases of TALC revolve around its imaging capacities, that allow resolving the Kuiper belt in extra-solar planetary systems, or the filamentary scale in star forming clouds all the way to the Galactic Center, or the Narrow Line Region in Active Galactic Nuclei of the Local Group, or breaking the confusion limit to resolve the Cosmic Infrared Background. Equipping this telescope with detectors capable of imaging polarimetry offers as well the extremely interesting perspective to study the influence of the magnetic field in structuring the interstellar medium. We will then present simulations of the optical performance of such a telescope. The main feature of an annular telescope is the small amount of energy contained in the main beam, around 30% for the studied configuration, and the presence of bright diffraction rings. Using simulated point spread functions for realistic broad-band filters, we study the observing performance of TALC in typical situations, i.e a field of point sources, and fields with emission power at every physical scales, taken to represent an extragalactic deep field observation and an interstellar medium observation. We investigate different inversion techniques to try and recover the information present in the input field. We show that techniques combining a forward modeling of the observation process and a reconstruction algorithm exploiting the concept of sparsity (i.e. related to the more general field of compressed sensing) represent a promising avenue to reach the angular resolution promised by the main beam of TALC.

Sauvage, Marc; Chanial, Pierre; Durand, Gilles A.; Rodriguez, Louis R.; Starck, Jean-Luc; Ronayette, Samuel; Aussel, Hervé; Minier, Vincent; Motte, Frédérique; Pantin, Eric J.; Sureau, Florent; Terrisse, Robin

2014-08-01

149

Telescope beam-profile diagnostics and the solar limb  

NASA Technical Reports Server (NTRS)

The basic method is described for determining the solar limb brightness profile properly corrected for spurious limb darkening caused by the far wings of the resolving beams encountered in large far-infrared and radio telescopes. When the far wings of the beam can be independently measured this problem is usually amenable to standard deconvolution procedures. Under a broad range of well-defined cases, solutions to the deconvolution problem are unique to within the discrimination provided by the core of the beam profile. The theory is applied to solar limb scans made recently on the James Clerk Maxwell Telscope to show solar limb brightening in 850 micron radiation.

Lindsey, Charles A.; Roellig, Thomas L.

1991-01-01

150

Telescope beam-profile diagnostics and the solar limb  

SciTech Connect

The basic method is described for determining the solar limb brightness profile properly corrected for spurious limb darkening caused by the far wings of the resolving beams encountered in large far-infrared and radio telescopes. When the far wings of the beam can be independently measured this problem is usually amenable to standard deconvolution procedures. Under a broad range of well-defined cases, solutions to the deconvolution problem are unique to within the discrimination provided by the core of the beam profile. The theory is applied to solar limb scans made recently on the James Clerk Maxwell Telscope to show solar limb brightening in 850 micron radiation. 16 refs.

Lindsey, C.A.; Roellig, T.L. (Hawaii, University, Honolulu (USA) NASA, Ames Research Center, Moffett Field, CA (USA))

1991-07-01

151

The Advanced Technology Solar Telescope: Science Goals, Design and Project Status. (Invited)  

NASA Astrophysics Data System (ADS)

The 4m Advance Technology Solar Telescope (ATST) on Haleakala will be the most powerful solar telescope and the world’s leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun’s output. The project is about to enter the construction phase and is expected to be fully commissioned in 2017. A brief overview of the science goals and observational requirements of the ATST will be given followed by a summary of the design status of the telescope and its instrumentation will during which the technical and engineering challenges the ATST project faces will be discussed. ATST will provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona. With its 4 m aperture, ATST will resolve features at 0.”03 (20km on the sun) at visible wavelengths. The science requirement for polarimetric sensitivity (10-5 relative to intensity) and accuracy (5x10-4 relative to intensity) place strong constraints on the polarization analysis and calibration units. A high order adaptive optics system delivers a corrected beam to the initial set of state-of-the-art, facility class instrumentation located in the Coude lab facility. A few examples of the many unique science capabilities of the 4m ATST will be discussed. The initial set of first generation instruments includes: 1: the Visible Broadband Imager will provide images at the highest possible spatial and temporal resolution at a number of specified wavelengths in the range from 390 nm to 860 nm. 2: the Visible Spectro-Polarimeter will provide precision vector field measurements simultaneously at diverse wavelengths in the visible spectrum and thus deliver quantitative diagnostics of the magnetic field vector as a function of height in the solar atmosphere, along with the associated variation of the thermodynamic properties. 3: the Diffraction-Limited Near-Infrared Spectro-Polarimeter will record with high temporal cadence the full polarization state of spectral lines in the near infrared wavelength regime from 900 nm to 2300 nm. 4: the Cryogenic Near Infrared-Spectro-Polarimeter will measure solar magnetic fields over a large field-of-view at infrared wavelengths from 1000 nm to 5000 nm in the solar corona. 5: the Visible Tunable Filter will provide two-dimensional spectroscopy and polarimetry by recording diffraction-limited narrow-bandpass images with high temporal resolution.

Rimmele, T.; Keil, S. L.; Wagner, J.

2009-12-01

152

Research of active panel technology for large aperture millimeter-wave/sub-millimeter-wave telescope  

NASA Astrophysics Data System (ADS)

As Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project was completed successfully, indicating the key technology of active optics has been mastered by the Chinese astronomical community, experts of Nanjing Institute of Astronomical Optics and Technology (NIAOT), builders of this project, started to consider how to use the technology developed in large optical telescope such as LAMOST to improve the performance of millimeterwave / sub-millimeter-wave telescope. In order to do more research work about active optics of millimeter submillimeter band and improve the performance of Delingha 13.7m millimeter-wave telescope, researchers of NIAOT intend to upgrade the reflect panel accuracy of this telescope. This paper will introduce the preliminary work of the accuracy-upgrading task, numerical simulation of the 13.7m telescope. In this presentation, the primary reflector finite element model (FEM) construction, gravity and thermal deformation, and modal analyze are described. The result shows that the gravity and thermal distortion of the reflector are contributed mostly by the back-structure and the active support for the panels is very necessary to restrain this kind of distortion.

Wu, Xuhao; Cui, Xiangqun

2010-05-01

153

Facility level thermal systems for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The management and control of the local aero-thermal environment is critical for success of the Advanced Technology Solar Telescope (ATST). In addition to minimizing disturbances to local seeing, the facility thermal systems must meet stringent energy efficiency requirements to minimize impact on the surrounding environment and meet federal requirements along with operational budgetary constraints. This paper describes the major facility thermal equipment and systems to be implemented along with associated energy management features. The systems presented include the central plant, the climate control systems for the computer room and coudé laboratory, the carousel cooling system which actively controls the surface temperature of the rotating telescope enclosure, and the systems used for active and passive ventilation of the telescope chamber.

Phelps, LeEllen; Murga, Gaizka; Fraser, Mark; Climent, Tŕnia

2012-09-01

154

IMAGING FAINT BROWN DWARF COMPANIONS CLOSE TO BRIGHT STARS WITH A SMALL, WELL-CORRECTED TELESCOPE APERTURE  

SciTech Connect

We have used our 1.6 m diameter off-axis well-corrected subaperture (WCS) on the Palomar Hale telescope in concert with a small inner-working-angle phase-mask coronagraph to image the immediate environs of a small number of nearby stars. Test cases included three stars (HD 130948, HD 49197, and HR7672) with known brown dwarf companions at small separations, all of which were detected. We also present the initial detection of a new object close to the nearby young G0V star HD171488. Follow-up observations are needed to determine if this object is a bona fide companion, but its flux is consistent with the flux of a young brown dwarf or low-mass M star at the same distance as the primary. Interestingly, at small angles our WCS coronagraph demonstrates a limiting detectable contrast comparable to that of extant Lyot coronagraphs on much larger telescopes corrected with current-generation adaptive optics (AO) systems. This suggests that small apertures corrected to extreme AO (ExAO) levels can be used to carry out initial surveys for close brown dwarf and stellar companions, leaving follow-up observations for larger telescopes.

Serabyn, E.; Mawet, D.; Bloemhof, E.; Haguenauer, P.; Mennesson, B.; Wallace, K. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Hickey, J. [Palomar Observatory, California Institute of Technology, P.O. Box 200, Palomar Mountain, CA 92060 (United States)

2009-05-01

155

The Advanced Technology Solar Telescope: design and early construction  

NASA Astrophysics Data System (ADS)

The National Solar Observatory’s (NSO) Advanced Technology Solar Telescope (ATST) is the first large U.S. solar telescope accessible to the worldwide solar physics community to be constructed in more than 30 years. The 4-meter diameter facility will operate over a broad wavelength range (0.35 to 28 ?m ), employing adaptive optics systems to achieve diffraction limited imaging and resolve features approximately 20 km on the Sun; the key observational parameters (collecting area, spatial resolution, spectral coverage, polarization accuracy, low scattered light) enable resolution of the theoretically-predicted, fine-scale magnetic features and their dynamics which modulate the radiative output of the sun and drive the release of magnetic energy from the Sun’s atmosphere in the form of flares and coronal mass ejections. In 2010, the ATST received a significant fraction of its funding for construction. In the subsequent two years, the project has hired staff and opened an office on Maui. A number of large industrial contracts have been placed throughout the world to complete the detailed designs and begin constructing the major telescope subsystems. These contracts have included the site development, AandE designs, mirrors, polishing, optic support assemblies, telescope mount and coudé rotator structures, enclosure, thermal and mechanical systems, and high-level software and controls. In addition, design development work on the instrument suite has undergone significant progress; this has included the completion of preliminary design reviews (PDR) for all five facility instruments. Permitting required for physically starting construction on the mountaintop of Haleakal?, Maui has also progressed. This paper will review the ATST goals and specifications, describe each of the major subsystems under construction, and review the contracts and lessons learned during the contracting and early construction phases. Schedules for site construction, key factory testing of major subsystems, and integration, test and commissioning activities will also be discussed.

McMullin, Joseph P.; Rimmele, Thomas R.; Keil, Stephen L.; Warner, Mark; Barden, Samuel; Bulau, Scott; Craig, Simon; Goodrich, Bret; Hansen, Eric; Hegwer, Steve; Hubbard, Robert; McBride, William; Shimko, Steve; Wöger, Friedrich; Ditsler, Jennifer

2012-09-01

156

Complex apodized Lyot coronagraph for exoplanet imaging with partially obscured telescope apertures  

NASA Astrophysics Data System (ADS)

We update the design, performance, and future prospects for the complex apodized Lyot coronagraph. We extend previous design work for off axis telescope with unobscured circular pupils, now to designs for high-contrast exoplanet imaging and spectroscopy with complicated pupil obscurations such as the WFIRST/AFTA telescope. Together with a pair of deformable mirrors for active wavefront control, the complex apodized Lyot coronagraph creates high contrast dark fields of view extending to within angular separations of 3 ?/D from the central star, over spectral bandwidths of 10% or more, and with throughput efficiencies greater than 35%.

Trauger, John; Moody, Dwight; Gordon, Brian

2013-09-01

157

Solar Adaptive Optics System for 1-m New Vacuum Solar Telescope  

NASA Astrophysics Data System (ADS)

The 1-m New Vacuum Solar Telescope (NVST), located at Full-shine Lake Solar Observatory, Kunming, Yunnan, is the largest solar telescope in China recently. A 37-elemnt low-order solar adaptive optics (AO) system had been developed and installed on the telescope in 2011, and AO-corrected high resolution solar images were obtained at wavelength 430.5nm, 705.7nm and 1555nm simultaneously. The low-order AO system can yield diffraction limited images only in the near infrared under good seeing and in the visible under excellent seeing, which cannot satisfy the requirement of Solar Physics study. A high-order AO system, which consists of a fine tracking loop with a tip/tilt mirror and a correlation tracker, and a high-order correction loop with a 127-element deformable mirror, a correlating Shack-Hartmann wavefront sensor and a real-time controller, is under development. A multi-conjugate adaptive optics (MCAO) experiments are also carried on the telescope. This paper summarizes the progress of the solar adaptive optics in China and presents the observational results of the low-order AO system. The design of the high-order AO system and MCAO experimental prototype are given.

Rao, Changhui; Zhu, Lei; Gu, Naiting; Rao, Xuejun; Zhang, Lanqiang

2013-12-01

158

The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers, Technology Developments, and Synergies with Other Future Facilities  

NASA Technical Reports Server (NTRS)

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers that define the main performance requirements for ATLAST (8 to 16 milliarcsec angular resolution, diffraction limited imaging at 0.5 m wavelength, minimum collecting area of 45 square meters, high sensitivity to light wavelengths from 0.1 m to 2.4 m, high stability in wavefront sensing and control). We will also discuss the synergy between ATLAST and other anticipated future facilities (e.g., TMT, EELT, ALMA) and the priorities for technology development that will enable the construction for a cost that is comparable to current generation observatory-class space missions.

Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Phillip; Tumlinson, Jason; Mountain, Matt; Soummer, Remi; Hyde, Tupper

2011-01-01

159

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry-BLASTPol: Performance and results from the 2012 Antarctic flight  

E-print Network

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) is a suborbital mapping experiment, designed to study the role played by magnetic fields in the star formation process. BLASTPol observes polarized light using a total power instrument, photolithographic polarizing grids, and an achromatic half-wave plate to modulate the polarization signal. During its second flight from Antarctica in December 2012, BLASTPol made degree scale maps of linearly polarized dust emission from molecular clouds in three wavebands, centered at 250, 350, and 500 microns. The instrumental performance was an improvement over the 2010 BLASTPol flight, with decreased systematics resulting in a higher number of confirmed polarization vectors. The resultant dataset allows BLASTPol to trace magnetic fields in star-forming regions at scales ranging from cores to entire molecular cloud complexes.

Galitzki, N; Angilé, F E; Benton, S J; Devlin, M J; Dober, B; Fissel, L M; Fukui, Y; Gandilo, N N; Klein, J; Korotkov, A L; Matthews, T G; Moncelsi, L; Netterfield, C B; Novak, G; Nutter, D; Pascale, E; Poidevin, F; Savini, G; Scott, D; Shariff, J A; Soler, J D; Tucker, C E; Tucker, G S; Ward-Thompson, D

2014-01-01

160

On the co-alignment of solar telescopes. A new approach to solar pointing  

NASA Astrophysics Data System (ADS)

Helioseismological measurements require long observing times and thus may be adversely affected by lateral image drifts as caused by pointing instabilities. At the Vacuum Tower Telescope VTT, Tenerife we have recorded drift values of up to 5" per hour under unstable thermal conditions (dome opening, strong day-to-day thermal gradients). Typically drifts of 0.5" - 1.0" per hour may be encountered under more favorable conditions. Past experience has shown that most high-resolution solar telescopes may be affected by this problem to some degree. This inherent shortcoming of solar pointing is caused by the fact that the guiding loop can be closed only within the guiding beam but not within the telescope's main beam. We have developed a new approach to this problem. We correlate continuum brightness patterns observed from within the telescope main beam with patterns originating from a full disk telescope. We show that brightness patterns of sufficient size are unique with respect to solar location at any instant of time and may serve as a location identifier. We make use of the fact that averaged location information of solar structures is invariant with respect to telescope resolution. We have carried out tests at the VTT together with SDO. We have used SDO as a full disk reference. We were able to reduce lateral image drifts by an order of magnitude.

Staiger, J.

2013-06-01

161

Construction status of the Daniel K. Inouye Solar Telescope  

NASA Astrophysics Data System (ADS)

The Daniel K. Inouye Solar Telescope (DKIST, renamed in December 2013 from the Advanced Technology Solar Telescope) will be the largest solar facility built when it begins operations in 2019. Designed and developed to meet the needs of critical high resolution and high sensitivity spectral and polarimetric observations of the Sun, the observatory will enable key research for the study of solar magnetism and its influence on the solar wind, flares, coronal mass ejections and solar irradiance variations. The 4-meter class facility will operate over a broad wavelength range (0.38 to 28 microns, initially 0.38 to 5 microns), using a state-of-the-art adaptive optics system to provide diffraction-limited imaging and the ability to resolve features approximately 25 km on the Sun. Five first-light instruments will be available at the start of operations: Visible Broadband Imager (VBI; National Solar Observatory), Visible SpectroPolarimeter (ViSP; NCAR High Altitude Observatory), Visible Tunable Filter (VTF; Kiepenheuer Institut für Sonnenphysik), Diffraction Limited Near InfraRed SpectroPolarimeter (DL-NIRSP; University of Hawai'i, Institute for Astronomy) and the Cryogenic Near InfraRed SpectroPolarimeter (Cryo-NIRSP; University of Hawai'i, Institute for Astronomy). As of mid-2014, the key subsystems have been designed and fabrication is well underway, including the site construction, which began in December 2012. We provide an update on the development of the facilities both on site at the Haleakal? Observatories on Maui and the development of components around the world. We present the overall construction and integration schedule leading to the handover to operations in mid 2019. In addition, we outline the evolving challenges being met by the project, spanning the full spectrum of issues covering technical, fiscal, and geographical, that are specific to this project, though with clear counterparts to other large astronomical construction projects.

McMullin, Joseph P.; Rimmele, Thomas R.; Martínez Pillet, Valentin; Berger, Thomas E.; Casini, Roberto; Craig, Simon C.; Elmore, David F.; Goodrich, Bret D.; Hegwer, Steve L.; Hubbard, Robert P.; Johansson, Erik M.; Kuhn, Jeffrey R.; Lin, Haosheng; McVeigh, William; Schmidt, Wolfgang; Shimko, Steve; Tritschler, Alexandra; Warner, Mark; Wöger, Friedrich

2014-07-01

162

Observing Solar System Targets with the James Webb Space Telescope  

NASA Astrophysics Data System (ADS)

With its anticipated launch date in October 2018, the James Webb Space Telescope will tremendously advance astronomy in the near- and mid-infrared, offering sensitivity and spatial/spectral resolution greatly surpassing its predecessors. We have developed a white paper that explores observations of Solar System targets with JWST, with the goals of highlighting anticipated Solar System capabilities, motivation of potential observers, and encouragement of further interest and discussion. This paper presents the most current information available concerning JWST instrument properties and observing techniques relevant to planetary science. It also illustrates example observing scenarios for a wide variety of Solar System objects, including the giant planets, Kuiper Belt objects, Europa, Titan, and more. We are also collaborating with a set of focus groups that have expanded upon this work, producing a series of further white papers dealing with individual subdisciplines. This work has been supported by NASA Grant NAG5-12457.

Norwood, James; Hammel, Heidi; Milam, Stefanie; Stansberry, John; Lunine, Jonathan; Chanover, Nancy; Hines, Dean; Sonneborn, George; Tiscareno, Matthew; Brown, Michael; Ferruit, Pierre

2014-11-01

163

An Airborne Infrared Telescope and Spectrograph for Solar Eclipse Observations  

NASA Astrophysics Data System (ADS)

The solar infrared spectrum offers great possibilities for direct spatially resolved measurements of the solar coronal magnetic fields, via imaging of the plasma that is constrained to follow the magnetic field direction and via spectro-polarimetry that permits measurement of the field strength in the corona. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections (CME) and provides the ultimate source of energy for space weather. The large scale structure of the coronal field, and the opening up of the field in a transition zone between the closed and open corona determines the speed and structure of the solar wind, providing the background environment through which CMEs propagate. At present our only direct measurements of the solar magnetic fields are in the photosphere and chromosphere. The ability to determine where and why the corona transitions from closed to open, combined with measurements of the field strength via infrared coronal spectro-polarimetry will give us a powerful new tool in our quest to develop the next generation of forecasting models.We describe a first step in achieving this goal: a proposal for a new IR telescope, image stabilization system, and spectrometer, for the NCAR HIPER GV aircraft. The telescope/spectrograph will operate in the 2-6micron wavelength region, during solar eclipses, starting with the trans-north American eclipse in August 2017. The HIAPER aircraft flying at ~35,000 ft will provide an excellent platform for IR observations. Our imaging and spectroscopy experiment will show the distribution and intensity of IR forbidden lines in the solar corona.

DeLuca, Edward E.; Cheimets, Peter; Golub, Leon

2014-06-01

164

The soft x ray telescope for Solar-A  

NASA Technical Reports Server (NTRS)

The Solar-A satellite being prepared by the Institute for Sapce and Astronautical Sciences (ISAS) in Japan is dedicated to high energy observations of solar flares. The Soft X Ray Telescope (SXT) is being prepared to provide filtered images in the 2 to 60 A interval. The flight model is now undergoing tests in the 1000 foot tunnel at MSFC. Launch will be in September 1991. Earlier resolution and efficiency tests on the grazing incidence mirror have established its performance in soft x rays. The one-piece, two mirror grazing incidence telescope is supported in a strain free mount separated from the focal plane assembly by a carbon-epoxy metering tube whose windings and filler are chosen to minimize thermal and hygroscopic effects. The CCD detector images both the x ray and the concentric visible light aspect telescope. Optical filters provide images at 4308 and 4700 A. The SXT will be capable of producing over 8000 of the smallest partial frame images per day, or fewer but larger images, up to 1024 x 1024 pixel images. Image sequence with two or more of the five x ray analysis filters, with automatic exposure compensation to optimize the charge collection by the CCD detector, will be used to provide plasma diagnostics. Calculations using a differential emission measure code were used to optimize filter selection over the range of emission measure variations and to avoid redundancy, but the filters were chosen primarily to give ratios that are monotonic in plasma temperature.

Brown, W. A.; Acton, L. W.; Bruner, M. E.; Lemen, J. R.; Strong, K. T.

1989-01-01

165

Site-seeing measurements for the European Solar Telescope  

NASA Astrophysics Data System (ADS)

Seeing measurements are crucial for the optimum design of (multi-conjugate) adaptive optics systems operating at solar telescopes. For the design study of the 4-meter European Solar Telescope, to be located in the Canary Islands, several instruments have been constructed and operated, at the Observatorio del Roque de los Muchachos (La Palma) and at the Observatorio del Teide (Tenerife), to measure the properties of the ground layer and medium-high altitude turbulence. Several units of short (42.34 cm) and two long (323.06 cm) scintillometer bars are, or are to be, installed at both observatories. In addition to them, two wide-field wavefront sensors will be attached to the optical beams of the Swedish tower, on La Palma, and of the German VTT, on Tenerife, simultaneously used with the normal operation of the telescopes. These wavefront sensors are of Shack-Hartmann type with ~1 arcminute field of view. In this contribution, the instruments setup and their performance are described.

Berkefeld, Th.; Bettonvil, F.; Collados, M.; López, R.; Martín, Y.; Peńate, J.; Pérez, A.; Scharmer, G. B.; Sliepen, G.; Soltau, D.; Waldmann, T. A.; van Werkhoven, T.

2010-07-01

166

High-contrast imager for Complex Aperture Telescopes (HiCAT): APLC/shaped-pupil hybrid coronagraph designs  

NASA Astrophysics Data System (ADS)

HiCAT is a high-contrast imaging testbed designed to provide complete solutions in wavefront sensing, control and starlight suppression with complex aperture telescopes. Primary mirror segmentation, central obstruction and spiders in the pupil of an on-axis telescope introduces additional diffraction features in the point spread function, which make high-contrast imaging very challenging. The testbed alignment was completed in the summer of 2014, exceeding specifications with a total wavefront error of 12nm rms with a 18mm pupil. Two deformable mirrors are to be installed for wavefront control in the fall of 2014. In this communication, we report on the first testbed results using a classical Lyot coronagraph. We have developed novel coronagraph designs combining an Apodized Pupil Lyot Coronagraph (APLC) with shaped-pupil type optimizations. We present the results of these new APLC-type solutions with two-dimensional shaped-pupil apodizers for the HiCAT geometry. These solutions render the system quasi-insensitive to jitter and low-order aberrations, while improving the performance in terms of inner working angle, bandpass and contrast over a classical APLC.

N'Diaye, Mamadou; Choquet, Elodie; Carlotti, Alexis; Pueyo, Laurent; Egron, Sylvain; Leboulleux, Lucie; Levecq, Olivier; Perrin, Marshall D.; Wallace, J. Kent; Long, Chris; Lajoie, Rachel; Lajoie, Charles-Philippe; Eldorado Riggs, A. J.; Zimmerman, Neil T.; Groff, Tyler Dean; Kasdin, N. Jeremy; Vanderbei, Robert J.; Mawet, Dimitri; Macintosh, Bruce; Shaklan, Stuart; Soummer, Remi

2015-01-01

167

Considerations for the next generation of solar telescopes: A systems approach to solar physics  

NASA Astrophysics Data System (ADS)

The exciting new high resolution images from the one meter Sunrise balloon telescope and the first images from the 1.6 meter Big Bear telescope together with the continuing data from the 1 meter Swedish Solar Observatory demonstrate the promise of the new generation of multimeter solar telescopes. While the promise of the new generation of telescopes is great the technical challenges to build them will require the efforts of a significant fraction of the solar community. In this talk I will emphasize the need for an integrated systems approach to the development of the telescope, its instruments, its software, and its operations and management structures. The experience of several decades of space mission has taught us a great deal about the value of planning mission development from the definition of the primary scientific objectives to the delivery of the data to the science community. Much of these lessons learned, often painfully, should provide guidance to those in developing the new telescope systems.

Title, A.

2010-06-01

168

Comparison of Solar Photometric Data from Two Telescopes  

NASA Astrophysics Data System (ADS)

Sunspot areas from two photometric telescopes have been compared. The two telescopes are the Precision Solar Photometric Telescope (PSPT) operated on Mauna Loa by the High Altitude Observatory (HAO) and the Cartesian Full Disk Telescope 2 (CFDT2) operated at the San Fernando Observatory (SFO). The PSPT images originally 2048 x 2048 have been binned by two to agreee more closely with those from CFDT2. The binned PSPT pixels are 2" x 2" and the CFDT2 pixels are 2.5" x 2.5". A preliminary analysis shows that sunspot areas from the two are highly correlated although only seven image pairs have been correlated. Comparing the red PSPT spot areas with the red CFDT2 spot areas gives an r2 of 0.9947 and a scale factor of 0.909 +/- 0.03 where the scale factor implies the red areas are slightly too small. For CFDT2 blue images versus the red PSPT the r2 is 0.9895 with a scale factor of 1.06 +/- 0.05 implying that the blue areas are slightly too large. Results from other wavelengths and from an expanded data set will be presented and discussed. This research was partially supported by grants from NSF, NASA and a visiting scientist grant from HAO.

Chapman, G. A.; Walton, S. R.; deToma, G.; White, O. R.

2001-12-01

169

Fibered nulling telescope for extra-solar coronagraphy.  

PubMed

A family of fibered nulling telescopes is described, based on the joint use of several recent suggested or demonstrated techniques, namely, pupil densification, multiaxial recombination and single-mode fiber modal filtering, and the use of a fully symmetric beam splitter arrangement. The concept seems appropriate for the realization of a spaceborne nulling telescope, searching for Jupiter-like extra-solar planets and a precursor of future missions, such as Darwin or terrestrial planet finder interferometer (TPF-I). However, it is generally not possible to satisfy at the same time two major requirements, being the depth and size of the central nulling area, and the global throughput for the observed planet. PMID:19340231

Hénault, François

2009-04-01

170

New Solar Telescope Observations of Magnetic Reconnection Occurring in the Chromosphere of the Quiet Sun  

E-print Network

New Solar Telescope Observations of Magnetic Reconnection Occurring in the Chromosphere changes in a magnetized plasma. On the solar surface, it often occurs with the cancellation of two magnetic fragments of opposite polarity. Using the 1.6 meter New Solar Telescope, we observed

171

High resolution solar observations: the hydrogen-alpha telescopes on Skylab.  

PubMed

Two hydrogen-alpha telescopes were flown as part of the solar astronomy instruments on Skylab. These telescopes provided high resolution video imagery to the crew for both solar surveillance and the pointing of the entire instrument cluster. A film camera on one telescope provided photographs for a postmission pointing record. This paper details the design of the telescopes and their operating characteristics and presents an evaluation of their performance during the mission. PMID:20168612

Markey, J F; Austin, R R

1977-04-01

172

The Daniel K. Inouye Solar Telescope: A Project Update.  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope will be the largest solar facility ever built. Designed and developed to meet the needs of critical high resolution and high sensitivity spectral and polarimetric observations of the sun, this facility will support key experiments for the study of solar magnetism and its influence on the solar wind, flares, coronal mass ejections and solar irradiance variability. The 4-meter diameter facility will operate over a broad wavelength range (0.35 to 28 microns), using state-of-the-art adaptive optics systems to provide diffraction limited imaging and the ability to resolve features approximately 20 km on the Sun. Five first light instruments will be available at the start of operations. Key subsystems have been designed and fabrication is well underway, including the site construction, which began in December 2012. We provide an update on the development of the facilities both on site at the Haleakala Observatories in Maui and the development of components around the world. We present the overall construction and integration schedule leading to the start of operations in mid-2019 and touch on operations aspects.

Rimmele, T.; Berger, T.; McMullin, J.; Warner, M.; Casinsi, R.; Kuhn, J.; Lin, H.; Woeger, F.; Schmidt, W.; Tritschler, A.; Inouye, Daniel K.; Solar Telescope Team

2014-09-01

173

The design, construction and testing of the optics for a 147-cm-aperture telescope  

NASA Technical Reports Server (NTRS)

Geodetic optics research for the Air Force Cambridge Research Laboratories (AFCRL) is described. The work consisted mainly of the fabrication of the optical components for a telescope with a 152-cm-diam (60-in.) primary mirror masked down to 147-cm-diam for use by the AFCRL for a lunar ranging experiment. Among the achievements of this contract were the following: completion of the primary and secondary mirrors for a high-quality 147-cm-diam telescope system in eight months from the start of edging the primary; manufacture and testing of a unique center mount for the primary according to an AFCRL design that allowed for a thin-edged and therefore less-massive mirror; and development of a quantitative analysis of the wire test for calculating the departure of the mirror figure from the design figure quickly and accurately after each polishing step. This analysis method in conjunction with a knowledge of polishing rates for given weights and diameters of tools, mirror, and polishing materials should considerably reduce the polishing time required for future large mirrors.

Buchroeder, R. A.; Elmore, L. H.; Shack, R. V.; Slater, P. N.

1972-01-01

174

What Makes The Advanced Technology Solar Telescope (ATST) So Advanced?  

NASA Astrophysics Data System (ADS)

-- Its the science! While its true that we haven't advanced ground-based solar astronomy by a leap as big as this since Galileo, its the qualitatively new insights that we expect with ATST that drive its design. ATST isn't so much a telescope as much as it is a sensitive magnetometer, and a high dynamic range imaging spectropolarimeter. In this talk we'll try to draw the lines between the questions you've always wanted to ask about the Sun, and this unique optical and infrared instrument.

Kuhn, Jeffrey R.; Rimmele, T.; ATST Design Team

2007-05-01

175

DETECTION OF SMALL-SCALE GRANULAR STRUCTURES IN THE QUIET SUN WITH THE NEW SOLAR TELESCOPE  

SciTech Connect

Results of a statistical analysis of solar granulation are presented. A data set of 36 images of a quiet-Sun area on the solar disk center was used. The data were obtained with the 1.6 m clear aperture New Solar Telescope at Big Bear Solar Observatory and with a broadband filter centered at the TiO (705.7 nm) spectral line. The very high spatial resolution of the data (diffraction limit of 77 km and pixel scale of 0.''0375) augmented by the very high image contrast (15.5% {+-} 0.6%) allowed us to detect for the first time a distinct subpopulation of mini-granular structures. These structures are dominant on spatial scales below 600 km. Their size is distributed as a power law with an index of -1.8 (which is close to the Kolmogorov's -5/3 law) and no predominant scale. The regular granules display a Gaussian (normal) size distribution with a mean diameter of 1050 km. Mini-granular structures contribute significantly to the total granular area. They are predominantly confined to the wide dark lanes between regular granules and often form chains and clusters, but different from magnetic bright points. A multi-fractality test reveals that the structures smaller than 600 km represent a multi-fractal, whereas on larger scales the granulation pattern shows no multi-fractality and can be considered as a Gaussian random field. The origin, properties, and role of the population of mini-granular structures in the solar magnetoconvection are yet to be explored.

Abramenko, V. I.; Yurchyshyn, V. B.; Goode, P. R. [Big Bear Solar Observatory, 40386 N. Shore Lane, Big Bear City, CA 92314 (United States); Kitiashvili, I. N.; Kosovichev, A. G. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

2012-09-10

176

Goldhelox: a soft X-ray solar telescope.  

NASA Astrophysics Data System (ADS)

The Goldhelox Project is the construction and use of a near-normal incidence soft X-ray robotic solar telescope by undergraduate students at Brigham Young University. Once it is completed and tested, it will be deployed from a Get-Away-Special (GAS) canister in the bay of a Space Shuttle. It will image the Sun at a wavelength of 171 - 181 Ĺ with a time resolution of 1 sec and a spatial resolution of 2.5 arcsec. The observational bandpass was chosen to image X-rays from highly ionized coronal Fe lines. The data will be an aid in better understanding the beginning phases of solar flares and how flaring relates to the physics of the corona-chromosphere transition region. Goldhelox is tentatively scheduled to fly on a Space Shuttle sometime in 1995 or 1996. This paper outlines the project goals, basic instrument design, and the unique aspects of making this an undergraduate endeavor.

Durfee, D. S.; Moody, J. W.; Brady, K. D.; Brown, C.; Campbell, B.; Durfee, M. K.; Early, D.; Hansen, E.; Madsen, D. W.; Morey, D. B.; Roming, P. W. A.; Savage, M. B.; Eastman, P. F.; Jensen, V.

1995-03-01

177

Observing Solar System Objects with the James Webb Space Telescope  

NASA Technical Reports Server (NTRS)

The James Webb Space Telescope (JWST) will have the capability to observe Solar System objects having apparent rates of motion up to 30 milliarcseconds/sec. The key science drivers are the study of Kuiper Belt Objects, asteroids, comets, and the outer planets and their moons at near and mid-infrared wavelengths. This poster presents the results from a recent study that defined the conceptual design for a capability for JWST to track and observe moving targets. We illustrate about how guide star acquisition and tracking wi11 be handled while retaining the efficient and flexible execution characteristics of JWST event-driven operations. We also show how the JWST pointing control system can readily support moving target observations. The characteristics of Solar System objects that can be observed by JWST are summarized along with descriptions of the major aspects of moving target science observation planning and on-board event-driven execution.

Sonneborn, George; Issacs, J.; Balzano, V.; Nelan, E.P.; Anandakrishnan, S.; Hammel, H.

2008-01-01

178

Mechanical analysis and thermal calculation in Space Solar Telescope  

NASA Astrophysics Data System (ADS)

Space frame including satellite platform is the most important structure part in Space Solar Telescope (SST), which is designed to make observations of transient and steady state solar hydrodynamic and magnetohydrodynamic processes. This paper first introduces the space frame, which is not only a crucial linker between the optical and other subsystems but also a mechanical interface for the telescope and launching rocket. It must satisfy the optics with sufficient strength, stiffness, and thermal stability under the space environment and in the launching process. Then the author sets up finite element analysis model by MSC.Patran software and analyzes the mechanical quality under different load cases such as on-ground, during launching and in-orbit. In order to simulate the space environment and evaluate the influence of space heat to the whole space frame, the paper also presents space thermal calculation and analysis. Calculation results show that this space frame can meet the satellite"s requirements in space running. However, the thermal problem is still serious in primary mirror, which needs to be tested and controlled with strict way. Finally, the paper gives conclusions and forward suggestions, which will be applied to further research and fabrication in SST.

Chen, Zhiping; Chen, Zhiyuan; Yang, Shimo; Shi, Huli

2004-10-01

179

Active optical alignment of the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) is a complex off-axis Gregorian design to be used for solar astronomy. In order the counteract the effects of mirror and telescope structure flexure, the ATST requires an active optics alignment strategy. This paper presents an active optics alignment strategy that uses three wavefront sensors distributed in the ATST field-of-view to form a least-squares alignment solution with respect to RMS wavefront error. The least squares solution is realized by means of a damped least squares linear reconstructor. The results of optical modelling simulations are presented for the ATST degrees-of-freedom subject to random perturbations. Typical results include residual RMS wavefront errors less than 20 nm. The results quoted include up to 25 nm RMS wavefront sensor signal noise, random figure errors on the mirrors up to 500 nm amplitude, random decenter range up to 500 ?m, and random tilts up to 10e - 03 degrees (36 arc-secs) range.

Upton, Robert; Rimmele, Thomas; Hubbard, Robert

2006-06-01

180

The Solar Optical Telescope on Hinode: Performance and Capabilities  

NASA Astrophysics Data System (ADS)

The Hinode (Solar B) satellite includes the Solar Optical Telescope (SOT) with its 50 cm diameter Optical Telescope Assembly (OTA) and Focal Plane Package (FPP), for near UV and visible observations of the photosphere and chromosphere at very high (diffraction limited) angular resolution. The FPP has a Spectropolarimeter (SP) for precision measurements of photospheric vector magnetic fields over a 160 x 320 arcsecond field of view; a Narrowband Filter Imager (NFI) with a tunable birefringent filter for magnetic, Doppler, and intensity maps over the same field of view; and a Broadband Filter Imager (BFI) for highest resolution images in six wavelengths (G band, Ca II H, continua, etc.) over two thirds of that field of view. A polarization modulator in the telescope allows measurement of Stokes parameters at all wavelengths in the SP and NFI. This poster gives examples of SOT observables from the performance verification and initial observing phases of the mission. The SP routinely collects Stokes profiles with spatial resolution 0.16 arc seconds (pixel) and rms noise less than 0.001. Initially the NFI only made magnetograms in Fe I 6302.5 with rms noise less than 0.002; more recently it has begun to observe the other photospheric and chromospheric lines available. The BFI movies have unprecedented uniformity and stability for such high spatial resolution; cadence can be 4 seconds or less. All images are stabilized to 0.01 arc seconds by a tip tilt mirror and correlation tracker. The process for requesting Hinode observations is described, along with guidelines for SOT observing programs. Starting in May, 2007, the Hinode data policy becomes completely open, with all data available to the community immediately after receipt and reformatting at ISAS. Hinode is an international cooperative mission between JAXA/ISAS of Japan, NASA of the United States, PPARC of the United Kingdom, and ESA.

Tarbell, Theodore D.; Tsuneta, S.; SOT Team

2007-05-01

181

KAPAO: A Natural Guide Star Adaptive Optics System for Small Aperture Telescopes  

NASA Astrophysics Data System (ADS)

We describe KAPAO, our project to develop and deploy a low-cost, remote-access, natural guide star adaptive optics system for the Pomona College Table Mountain Observatory (TMO) 1-meter telescope. The system will offer simultaneous dual-band, diffraction-limited imaging at visible and near-infrared wavelengths and will deliver an order-of-magnitude improvement in point source sensitivity and angular resolution relative to the current TMO seeing limits. We have adopted off-the-shelf core hardware components to ensure reliability, minimize costs and encourage replication efforts. These components include a MEMS deformable mirror, a Shack-Hartmann wavefront sensor and a piezo-electric tip-tilt mirror. We present: project motivation, goals and milestones; the instrument optical design; the instrument opto-mechanical design and tolerances; and an overview of KAPAO Alpha, our on-the-sky testbed using off-the-shelf optics. Beyond the expanded scientific capabilities enabled by AO-enhanced resolution and sensitivity, the interdisciplinary nature of the instrument development effort provides an exceptional opportunity to train a broad range of undergraduate STEM students in AO technologies and techniques. The breadth of our collaboration, which includes both public (Sonoma State University) and private (Pomona and Harvey Mudd Colleges) undergraduate institutions has enabled us to engage students ranging from physics, astronomy, engineering and computer science in the all stages of this project. This material is based upon work supported by the National Science Foundation under Grant No. 0960343.

Severson, Scott A.; Choi, P. I.; Spjut, E.; Contreras, D. S.; Gilbreth, B. N.; McGonigle, L. P.; Morrison, W. A.; Rudy, A. R.; Xue, A.; Baranec, C.; Riddle, R.

2012-05-01

182

KAPAO-Alpha: An On-The-Sky Testbed for Adaptive Optics on Small Aperture Telescopes  

NASA Astrophysics Data System (ADS)

We present initial in-lab and on-sky results of a natural guide star adaptive optics instrument, KAPAO-Alpha, being deployed on Pomona College’s 1-meter telescope at Table Mountain Observatory. The instrument is an engineering prototype designed to help us identify and solve design and integration issues before building KAPAO, a low-cost, dual-band, natural guide star AO system currently in active development and scheduled for first light in 2013. The Alpha system operates at visible wavelengths, employs Shack-Hartmann wavefront sensing, and is assembled entirely from commercially available components that include: off-the-shelf optics, a 140-actuator BMC deformable mirror, a high speed SciMeasure Lil’ Joe camera, and an EMCCD for science image acquisition. Wavefront reconstruction operating at 1-kHz speeds is handled with a consumer-grade computer running custom software adopted from the Robo-AO project. The assembly and integration of the Alpha instrument has been undertaken as a Pomona College undergraduate thesis. As part of the larger KAPAO project, it is supported by the National Science Foundation under Grant No. 0960343.

Morrison, Will; Choi, P. I.; Severson, S. A.; Spjut, E.; Contreras, D. S.; Gilbreth, B. N.; McGonigle, L. P.; Rudy, A. R.; Xue, A.; Baranec, C.; Riddle, R.

2012-05-01

183

Lupus I Observations from the 2010 Flight of the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry  

E-print Network

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous observation at 250, 350, and 500 {\\mu}m. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarization on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry (The optical data were published in 1998 by J. Rizzo and collaborators.). The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I,...

Matthews, Tristan G; Angilč, Francesco E; Benton, Steven J; Chapin, Edward L; Chapman, Nicholas L; Devlin, Mark J; Fissel, Laura M; Fukui, Yasuo; Gandilo, Natalie N; Gundersen, Joshua O; Hargrave, Peter C; Klein, Jeffrey; Korotkov, Andrei L; Moncelsi, Lorenzo; Mroczkowski, Tony K; Netterfield, Calvin B; Novak, Giles; Nutter, David; Olmi, Luca; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A; Soler, Juan Diego; Tachihara, Kengo; Thomas, Nicholas E; Truch, Matthew D P; Tucker, Carole E; Tucker, Gregory S; Ward-Thompson, Derek

2013-01-01

184

First Solar System Results of the Spitzer Space Telescope  

NASA Technical Reports Server (NTRS)

The Spitzer Space Telescope, formerly known as SIRTF, is now operational and delivers unprecedented sensitivity for the observation of Solar System targets. Spitzer's capabilities and first general results were presented at the January 2004 AAS meeting. In this poster, we focus on Spitzer's performance for moving targets, and the first Solar System results. Spitzer has three instruments, IRAC, IRS, and MIPS. IRAC (InfraRed Array Camera) provides simultaneous images at wavelengths of 3.6, 4.5, 5.8, and 8.0 microns. IRS (InfraRed Spectrograph) has 4 modules providing low-resolution (R=60-120) spectra from 5.3 to 40 microns, high-resolution (R=600) spectra from 10 to 37 m, and an autonomous target acquisition system (PeakUp) which includes small-field imaging at 15 m. MIPS (Multiband Imaging Photometer for SIRTF) does imaging photometry at 24, 70, and 160 m and low-resolution (R=15-25) spectroscopy (SED) between 55 and 96 microns. Guaranteed Time Observer (GTO) programs include the moons of the outer Solar System, Pluto, Centaurs, Kuiper Belt Objects, and comets

VanCleve, J.; Cruikshank, D. P.; Stansberry, J. A.; Burgdorf, M. J.; Devost, D.; Emery, J. P.; Fazio, G.; Fernandez, Y. R.; Glaccum, W.; Grillmair, C.

2004-01-01

185

Flight hardware for the Hubble Space Telescope solar array damper  

NASA Astrophysics Data System (ADS)

The Hubble Space Telescope (HST) is currently operating with two flexible solar arrays (or 'wings'), referred to as SA2, that were installed during Servicing Mission 1. These flexible solar arrays are to be replaced with two rigid solar arrays, SA3, during Servicing Mission 3B which is currently scheduled for May, 2001. The key requirements for these arrays are to: (1) increase long term power to support the HST mission, (2) improve the jitter performance while maintaining stability margin requirements, and (3) withstand re-boost loads without astronaut or ground intervention. Analysis of the original SA3 design showed that the Pointing Control System (PCS) stability margin requirements would be violated because of the modal characteristics of the SA3 fundamental bending modes. One of the options to regain the stability margins was to increase the damping of these modes. Damping of 1.5% of critical of the SA3 fundamental bending modes, at the HST system level, is needed to meet stability margin requirements. Therefore, the development of a discrete damping device was undertaken to provide adequate damping of the SA3 fundamental bending modes for all operational conditions.

Maly, Joseph R.; Anandakrishnan, Satya M.; Pendleton, Scott C.; Shade, E.; Sills, J. W.

2000-04-01

186

Transient Small-Scale Magnetic Flux Emergence and Atmospheric Response Observed with New Solar Telescope and SDO  

NASA Astrophysics Data System (ADS)

State-of-the art solar instrumentation is now revealing the activity of the Sun at the highest temporal and spatial resolution. Granular-scale magnetic flux emergence and the response of the solar atmosphere is one of the key topics. Observations with the 1.6m aperture New Solar Telescope (NST) at Big Bear Solar Observatory (BBSO) are making next steps in our understanding of the solar surface structure. On August 7, 2013, NST observed active region NOAA 11810 in different photospheric and chromospheric wavelengths. The region displays a group of solar pores, in the vicinity of which we detected a site of emerging magnetic flux accompanied by intense and very confined abnormal granulation dynamics, observed in the photospheric TiO 7057 A with a resolution of 0.034 “/pix. Following the expansion of exploding granules in this site, we observed a sudden appearance of an extended surge in the HeI 10830A data (bandpass of 0.05 A). The SDO/HMI data used to study the evolution of the magnetic field and Doppler velocities reveal a short-lived emerging loop-like structure with strong upflows. We used the SDO/AIA data to investigate the response of the transition region and corona to the transient emerging flux phenomenon. We compare the results with previous observations, and propose a scenario for the production of plasma surges by the transient magnetic flux emergence events.

Vargas Domínguez, Santiago; Kosovichev, Alexander G.

2014-06-01

187

The IMaX polarimeter for the solar telescope SUNRISE of the NASA long duration balloon program  

NASA Astrophysics Data System (ADS)

On June 8th 2009 the SUNRISE mission was successfully launched. This mission consisted of a 1m aperture solar telescope on board of a stratospheric balloon within the Long Duration Balloon NASA program. The flight followed the foreseen circumpolar trajectory over the Artic and the duration was 5 days and 17 hours. One of the two postfocal instruments onboard was IMaX, the Imaging Magnetograph eXperiment. This instrument is a solar magnetograph which is a diffraction limited imager capable to resolve 100 km on the solar surface, and simultaneously a high sensitivity polarimeter (<10-3) and a high resolution spectrograph (bandwidth <70mĹ). The magnetic vectorial map can be extracted thanks to the well-know Zeeman effect, which takes place in the solar atoms, allowing to relate polarization and spectral measurements to magnetic fields. The technological challenge of the IMaX development has a special relevance due to the utilization of innovative technologies in the Aeroespacial field and it is an important precedent for future space missions such as Solar Orbiter from ESA. Among these novel technologies the utilization of Liquid Crystal Variable Retarders (LCVRs) as polarization modulators and a LiNbO3 etalon as tunable spectral filter are remarkable. Currently the data obtained is being analyzed and the preliminary results show unprecedented information about the solar dynamics.

Alvarez-Herrero, A.; Martínez-Pillet, V.; Del Toro Iniesta, J. C.; Domingo, V.

2010-06-01

188

Thermal analysis of the main mirror in space solar telescope  

NASA Astrophysics Data System (ADS)

For the design of a space solar telescope (SST), the large reflect mirror faces to the sun directly, which is in an abominable thermal condition with seriously thermal distortion. In this paper, it sets up the thermal mode and analyzes the temperature field and thermal distortion of the main mirror of SST. Further more, it uses the thermal design software SINDA/G (System Improved Numerical Differencing Analyzer/Gaski) and the finite element analysis software MSC.Patran to set up different models and various temperature distributions of the main mirror. Though comparing with these models, the paraboloid mirror model is confirmed, which becomes a reference to later thermal analysis of the whole SST.

Li, Rong; Shi, Hu-li; Chen, Zhi-yuan

2007-12-01

189

First results from the CERN axion solar telescope.  

PubMed

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses. PMID:15903903

Zioutas, K; Andriamonje, S; Arsov, V; Aune, S; Autiero, D; Avignone, F T; Barth, K; Belov, A; Beltrán, B; Bräuninger, H; Carmona, J M; Cebrián, S; Chesi, E; Collar, J I; Creswick, R; Dafni, T; Davenport, M; Di Lella, L; Eleftheriadis, C; Englhauser, J; Fanourakis, G; Farach, H; Ferrer, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, I; Gninenko, S; Goloubev, N; Hasinoff, M D; Heinsius, F H; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Kang, D; Königsmann, K; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Laki?, B; Lasseur, C; Liolios, A; Ljubici?, A; Lutz, G; Luzón, G; Miller, D W; Morales, A; Morales, J; Mutterer, M; Nikolaidis, A; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Ruz, J; Riege, H; Sarsa, M L; Savvidis, I; Serber, W; Serpico, P; Semertzidis, Y; Stewart, L; Vieira, J D; Villar, J; Walckiers, L; Zachariadou, K

2005-04-01

190

Kitt Peak 60-cm vacuum telescope. [for solar astronomy  

NASA Technical Reports Server (NTRS)

A major new solar-research telescope conceived and built during a time of budget restraint is described. The observation of magnetic and velocity (circulation) field structure on a synoptic basis and with diffraction-limited resolution is the aim. New optical features include the use of oversize mirrors and windows to avoid thermal edge effects and the placement of the coelostat feed outside the vacuum, mainly for economy. The site selected has prevailing winds that clear thermals from these mirrors. Test data in the form of the system MTF and optical transmission, together with examples of full disk magnetograms and photoheliograms, show present performance capability. Measured MTF indicates a response of 0.2 at 1 sec of arc (whereas diffraction-limited response would be about 0.8). System transmission, including the accompanying spectrograph, is only 2-3% (wavelength 0.44-1.1 microns). Thus, both the optical quality and efficiency are subject to improvement.

Livingston, W. C.; Harvey, J.; Pierce, A. K.; Schrage, D.; Gillespie, B.; Simmons, J.; Slaughter, C.

1976-01-01

191

Optical control of the Advanced Technology Solar Telescope.  

PubMed

The Advanced Technology Solar Telescope (ATST) is an off-axis Gregorian astronomical telescope design. The ATST is expected to be subject to thermal and gravitational effects that result in misalignments of its mirrors and warping of its primary mirror. These effects require active, closed-loop correction to maintain its as-designed diffraction-limited optical performance. The simulation and modeling of the ATST with a closed-loop correction strategy are presented. The correction strategy is derived from the linear mathematical properties of two Jacobian, or influence, matrices that map the ATST rigid-body (RB) misalignments and primary mirror figure errors to wavefront sensor (WFS) measurements. The two Jacobian matrices also quantify the sensitivities of the ATST to RB and primary mirror figure perturbations. The modeled active correction strategy results in a decrease of the rms wavefront error averaged over the field of view (FOV) from 500 to 19 nm, subject to 10 nm rms WFS noise. This result is obtained utilizing nine WFSs distributed in the FOV with a 300 nm rms astigmatism figure error on the primary mirror. Correction of the ATST RB perturbations is demonstrated for an optimum subset of three WFSs with corrections improving the ATST rms wavefront error from 340 to 17.8 nm. In addition to the active correction of the ATST, an analytically robust sensitivity analysis that can be generally extended to a wider class of optical systems is presented. PMID:16926876

Upton, Robert

2006-08-10

192

Optical control of the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) is an off-axis Gregorian astronomical telescope design. The ATST is expected to be subject to thermal and gravitational effects that result in misalignments of its mirrors and warping of its primary mirror. These effects require active, closed-loop correction to maintain its as-designed diffraction-limited optical performance. The simulation and modeling of the ATST with a closed-loop correction strategy are presented. The correction strategy is derived from the linear mathematical properties of two Jacobian, or influence, matrices that map the ATST rigid-body (RB) misalignments and primary mirror figure errors to wavefront sensor (WFS) measurements. The two Jacobian matrices also quantify the sensitivities of the ATST to RB and primary mirror figure perturbations. The modeled active correction strategy results in a decrease of the rms wavefront error averaged over the field of view (FOV) from 500 to 19 nm, subject to 10 nm rms WFS noise. This result is obtained utilizing nine WFSs distributed in the FOV with a 300 nm rms astigmatism figure error on the primary mirror. Correction of the ATST RB perturbations is demonstrated for an optimum subset of three WFSs with corrections improving the ATST rms wavefront error from 340 to 17.8 nm. In addition to the active correction of the ATST, an analytically robust sensitivity analysis that can be generally extended to a wider class of optical systems is presented.

Upton, Robert

2006-08-01

193

HUBBLE SPACE TELESCOPE SPECTROPHOTOMETRY AND MODELS FOR SOLAR ANALOGS  

SciTech Connect

Absolute flux distributions for seven solar analog stars are measured from 0.3 to 2.5 {mu}m by Hubble Space Telescope (HST) spectrophotometry. In order to predict the longer wavelength mid-IR fluxes that are required for James Webb Space Telescope calibration, the HST spectral energy distributions are fit with Castelli and Kurucz model atmospheres; and the results are compared with fits from the MARCS model grid. The rms residuals in 10 broadband bins are all <0.5% for the best fits from both model grids. However, the fits differ systematically: the MARCS fits are 40-100 K hotter in T {sub eff}, 0.25-0.80 higher in log g, 0.01-0.10 higher in log z, and 0.008-0.021 higher in the reddening E(B - V), probably because their specifications include different metal abundances. Despite these differences in the parameters of the fits, the predicted mid-IR fluxes differ by only {approx}1%; and the modeled flux distributions of these G stars have an estimated ensemble accuracy of 2% out to 30 {mu}m.

Bohlin, R. C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)], E-mail: bohlin@stsci.edu

2010-04-15

194

A conceptual design for a Cassegrain-mounted high-resolution optical spectrograph for large-aperture telescopes  

NASA Astrophysics Data System (ADS)

We present a conceptual design for a high-resolution optical spectrograph appropriate for mounting at Cassegrain on a large aperture telescope. The design is based on our work for the Gemini High Resolution Optical Spectrograph (CUGHOS) project. Our design places the spectrograph at Cassegrain focus to maximize throughput and blue wavelength coverage, delivering R=40,000 resolving power over a continuous 320-1050 nm waveband with throughputs twice those of current instruments. The optical design uses a two-arm, cross-dispersed echelle format with each arm optimized to maximize efficiency. A fixed image slicer is used to minimize optics sizes. The principal challenge for the instrument design is to minimize flexure and degradation of the optical image. To ensure image stability, our opto-mechanical design combines a cost-effective, passively stable bench employing a honeycomb aluminum structure with active flexure control. The active flexure compensation consists of hexapod mounts for each focal plane with full 6-axis range of motion capability to correct for focus and beam displacement. We verified instrument performance using an integrated model that couples the optical and mechanical design to image performance. The full end-to-end modeling of the system under gravitational, thermal, and vibrational perturbations shows that deflections of the optical beam at the focal plane are <29 ?m per exposure under the worst case scenario (<10 ?m for most orientations), with final correction to 5 ?m or better using open-loop active control to meet the stability requirement. The design elements and high fidelity modeling process are generally applicable to instruments requiring high stability under a varying gravity vector.

Froning, Cynthia S.; Osterman, Steven; Burgh, Eric; Beasley, Matthew; Scowen, Paul; Veach, Todd; Jordan, Steven; Ebbets, Dennis; Lieber, Michael; deCino, James; Castilho, Bruno Vaz; Gneiding, Clemens; César de Oliveira, Antonio

2013-09-01

195

Future Diagnostic Capabilities: The 4-meter Daniel K. Inouye Solar Telescope  

NASA Astrophysics Data System (ADS)

We discuss the observational capabilities of the Daniel K. Inouye Solar Telescope (DKSIT), formerly known as the Advanced Technology Solar Telescope (ATST), currently under construction on Haleakala Mountain on the island of Maui, Hawaii, with first light anticipated in mid-2019. The DKIST will be a 4-meter aperture Gregorian telescope with advanced environmental control and adaptive optics capable of producing diffraction-limited resolution in visible light of 0.03" or about 20 km in the solar photosphere. The first light instrument suite will include the Visible Broadband Imager (VBI), an interference filter-based instrument capable of 30 Hz imaging of photospheric and chromospheric magnetic structures in the 380 to 800 nm wavelength range. All VBI images will be reconstructed in near-real-time using the KISIP speckle reconstruction algorithm adapted to the DKIST optical and AO configuration. The Visible Spectropolarimeter (ViSP) instrument being fabricated by the High Altitude Observatory (HAO) will enable high-precision slit-spectropolarimetery in any three spectral regions from 380 to 900 nm. The ViSP instrument will be the highest precision spectropolarimeter ever produced with a spatial resolution of approximately 40 km at 600 nm and temporal resolution of 10s to achieve 1e-03 polarimetric precision. The Visible Tunable Filter (VTF) instrument under fabrication at the Kiepenheuer Institute for Solar Physics (KIS) is a triple-etalon Fabry-Perot imaging spectropolarimeter instrument capable of diffraction limited measurements of the Fe I 630.2 nm and Ca II 854.2 nm spectral lines for Doppler and magnetic measurements in the photosphere and chromosphere, respectively. The VTF will also enable the highest spatial and temporal resolution observations yet achieved in the H-alpha line for detailed studies of chromospheric dynamics in response to photospheric magnetic drivers. The Diffraction-Limited Near-IR Spectropolarimeter (DL-NiRSP) and the Cryogenic Near-IR Spectropolarimeter (Cryo-NiRSP) instruments, both under fabrication at the University of Hawaii, will enable polarimetric and spectroscopic investigations in the largely unexplored infra-red spectral region. The DL-NiRSP will span 900 nm to 2.5 microns in wavelength and include a novel fiber-optic "Integral Field Unit" (IFU) for true imaging spectropolarimetry in three simultaneous spectral regions over a variable field of view. This instrument will enable revolutionary measurements of prominence magnetic fields and will also, in the wider field mode, enable coronal polarimetric studies. The Cryo-NiRSP instrument spans the 1--5 micron wavelength range and will make near-diffraction limited 0.3" resolution slit-scan measurements of the coronal magnetic field out to 1.3 solar radii with temporal resolution measured in minutes. The DKIST facility will undergo extensive polarimetric calibration to ensure that the ultimate goal of 5e-04 polarimetic precision is obtainable under the best conditions. All of the data from the DKIST will be transmitted to the central DKIST data center in Boulder, Colorado where automated reduction and calibration pipelines will rapidly provide the community with calibrated data products for use in science investigations. The DKIST will also be operated in a "Service Mode" access model in which investigators will not be required to travel to the telescope to accomplish their science observations.

Berger, Thomas; Reardon, Kevin; Elmore, David; Woeger, Friedrich; Tritschler, Alexandra; Rimmele, Thomas

196

Space solar telescope in soft X-ray and EUV band  

NASA Astrophysics Data System (ADS)

In this paper we have reviewed our achievements in soft X-ray and extreme ultraviolet (EUV) optics. Up to now, the research system of soft X-ray and EUV optics has been established, including light sources, detectors, calibrations, optical testing and machining of super smooth mirrors, and fabrications of multilayer film mirrors. Based on our achievements, we have developed two types of solar space telescopes for the soft X-ray and EUV space solar observations. One is an EUV multilayer normal incident telescope array including 4 different operation wavelength telescopes. The operation wavelengths of the EUV telescope are 13.0, 17.1, 19.5 and 30.4 nm. The other is a complex space solar telescope, which is composed of an EUV multilayer normal incident telescope and a soft X-ray grazing incident telescope. The EUV multilayer normal incident telescope stands in the central part of the soft X-ray grazing incident telescope. The normal incident telescope and the grazing incident telescope have a common detector. The different operation wavelengths can be changed by rotating a filter wheel.

Chen, Bo; Liu, Zhen; Yang, Lin; Gao, Liang; He, Fei; Wang, Xiaoguang; Ni, Qiliang

2009-11-01

197

Telescopes and recording systems used by amateurs for studying planets in our solar system - an overview  

NASA Astrophysics Data System (ADS)

During the last couple of years, engaged amateur astronomers have benefited by the rapid development in the field of commercial CCD cameras, video techniques, and the availability of mirror telescopes with high quality. Until recently, such technical equipment and the related handling experience had been reserved to research institutes. This contribution presents the potential capabilities of amateur astronomers and describes the approach to the production of data. The quality of the used telescopes is described with respect to aperture and resolving power; as well as the quantum efficiency of the used sensitive b/w CCD cameras with respect to the detectable wavelength. Beyond these facts the necessary exposure times for CCD images using special filters are discussed. Today's amateur astronomers are able to image the bodies of the solar system in the wavelength range between 340 and 1050 nm [1], [2], [3], [4]. This covers a wide range of the spectrum which is investigated with cameras on board of space telescopes or planetary probes. While space probes usually obtain high-resolution images of individual Surface or atmospheric features of the planets, the images of amateur astronomers show the entire surface of the observed planet. Both datasets together permit a more comprehensive analysis of the data aquired in each case. The "Venus Amateur Observing Project" of the European Space Agency [5] is a first step into a successful co-operation between amateur astronomers and planetary scientists. Individual CCD images captured through the turbulent atmosphere of the Earth usually show characteristic distortions of the arriving wave fronts. If one captures hundreds or thousands of images on a video stream in very short time, there will be always also undistorted images within the data. Computer programmes are available to identify and retrieve these undistorted images and store them for further processing [7]. This method is called "Lucky Imaging" and it allows to achieve nearly the theoretical limit of telescopic resolution. By stacking the undistorted images, the signal-to-noise ratio of the data can be increased significantly. "Lucky Imaging" has become a standard in the amateur community since several years. Contrary to space based observations the data rate is not limited by the capacity of any radio transmission, but only limited by the scanning rate and capacity of a modern computer hard disk. An individual video with the uncompreesed raw data can be as large as 4 to 5 GB. EPSC Abstracts, Vol. 3, EPSC2008-A-00191, 2008 European Planetary Science Congress, Author(s) 2008 In addition to the video data, so-called meta data such as the observing location, the recording time, the used filter, environmental conditions (air temperature, wind velocity, air humidity and Seeing) are also documented. From these meta data, the central meridian (CM) of the observed planet during the time of image acqusition can be determined. After data reduction the resulting images can be used to produce map projections or position measurements of albedo structures on the planetary surface or of details within atmospheric features. Amateur astronomers can observe objects in the solar system for large continuous time periods due to the large number of the existing observers e. g. the members of the Association of Lunar & Planetary Observers [6] and their telescopes. They can and react very fast to special events, since they do not have to submit requests for telescope time to a national or international organization. References: [1] Venusimages in uv-light: B. Gährken: http://www.astrode.de/venus07.htm R. Gerstheimer: http://www.astromanie.de/astromania/galerie/venus/venus.html S. Kowollik: http://www.sternwarte-zollern-alb.de/mitarbeiterseiten/kowollik/venus M. Weigand: http://www.skytrip.de/venus2007.htm [2] Images of planets in visible light: M. Fiedler: http://bilder.astroclub-radebeul.de/kategorien.php?action=showukats&kat=0 R. Gerstheimer: http://www.astromanie.de/ S. Kowollik: http://www.sternwarte-zoll

Kowollik, S.; Gaehrken, B.; Fiedler, M.; Gerstheimer, R.; Sohl, F.; Koschny, D.

2008-09-01

198

The 1.6 m Off-Axis New Solar Telescope (NST) in Big Bear  

NASA Astrophysics Data System (ADS)

The New Solar Telescope (NST) in Big Bear is the first facility-class solar telescope built in the US in a generation, and it has an off-axis design as is planned for the Advanced Technology Solar Telescope (ATST). The NST is in regular operation with adaptive optics (AO) correcting the light currently feeding photometric and near-IR polarimetric systems, as well as an imaging spectrograph. Here we show the high resolution capabilities of the NST. As well, we sketch our plans for, and reasoning behind the next generation NST instrumentation.

Goode, P. R.; Cao, W.

2012-12-01

199

The Focal Plane Package of the Solar Optical telescope on Solar B  

NASA Astrophysics Data System (ADS)

The Solar-B satellite will be launched into a full-sun low-earth orbit in the fall of 2006 from Japan's Uchinoura Space center. It includes the 50-cm diameter Solar Optical Telescope with its Focal Plane Package (FPP), for near-UV and visible observations of the photosphere and chromosphere at very high (diffraction limited) angular resolution. The FPP has a Spectro-Polarimeter (SP) for precision measurements of photospheric vector magnetic fields over a 160 x 320 arcsecond field of view; a Narrowband Filter Imager (NFI) with a tunable birefringent filter for magnetic, Doppler, and intensity maps over the same field of view; and a Broadband Filter Imager (BFI) for highest resolution images in six wavelengths (G band, Ca II H, continua, etc.) over two-thirds of that field of view. A polarization modulator in the telescope allows measurement of Stokes parameters at all wavelengths in the SP and NFI. The NFI wavelengths include both photospheric and chromospheric lines (Fe I, Mg b, Na D, H-alpha). All images are stabilized by a tip-tilt mirror and correlation tracker. This presentation will include pictures and description of the instrument, results from calibration and sun testing, portions of the draft science plan, and some preliminary JOP's. Solar-B is an international cooperative mission between JAXA/ISAS of Japan, NASA of the United States, and PPARC of the United Kingdom. The Solar Optical Telescope has been developed by the National Astronomical Observatory of Japan, Mitsubishi Electric Company, and JAXA/ISAS. The FPP has been developed by the Lockheed Martin Advanced Technology Center, High Altitude Observatory, and NASA.

Tarbell, Theodore D.

2006-06-01

200

Multi-conjugate AO for the European Solar Telescope  

NASA Astrophysics Data System (ADS)

The European Solar Telescope (EST) will be a 4-meter diameter world-class facility, optimized for studies of the magnetic coupling between the deep photosphere and upper chromosphere. It will specialize in high spatial resolution observations and therefore it has been designed to incorporate an innovative built-in Multi-Conjugate Adaptive Optics system (MCAO). It combines a narrow field high order sensor that will provide the information to correct the ground layer and a wide field low order sensor for the high altitude mirrors used in the MCAO mode. One of the challenging particularities of solar AO is that it has to be able to correct the turbulence for a wide range of observing elevations, from zenith to almost horizon. Also, seeing is usually worse at day-time, and most science is done at visible wavelengths. Therefore, the system has to include a large number of high altitude deformable mirrors. In the case of the EST, an arrangement of 4 high altitude DMs is used. Controlling such a number of mirrors makes it necessary to use fast reconstruction algorithms to deal with such large amount of degrees of freedom. For this reason, we have studied the performance of the Fractal Iterative Method (FriM) and the Fourier Transform Reconstructor (FTR), to the EST MCAO case. Using OCTOPUS, the end-to-end simulator of the European Southern Observatory, we have performed several simulations with both algorithms, being able to reach the science requirement of a homogeneous Strehl higher that 50% all over the 1 arcmin field of view.

Montilla, I.; Béchet, C.; Le Louarn, M.; Tallon, M.; Sánchez-Capuchino, J.; Collados Vera, M.

2012-07-01

201

Telescopes for solar research; from Scheiner's Helioscopium to De la Rue's Photoheliograph.  

NASA Astrophysics Data System (ADS)

Early telescopes used for solar observation were usually standard instruments, equipped with a filter or used in projection mode. The occasional exceptions were telescopes designed or modified for viewing, drawing, or photographing the sun. Christoph Scheiner observed sunspots regularly & systematically for 15 years, beginning early in 1611. A simple projection telescope was replaced with his Helioscopium, which was probably the first equatorially mounted telescope. Robert Hooke published a booklet in 1676 titled `Helioscopes', filled with an array of highly ingenious telescope designs, some of which were designed for solar observation and some of which were constructed and used. Warren De la Rue designed a photographic solar telescope, built by Andrew Ross in 1857 for the use of the Royal Society to establish a continuous record of solar activity. This photoheliograph was responsible for several important discoveries. Improvements in solar instruments led to advances in knowledge of the sun, and the contributions of some early solar telescopes and their makers will be recognized in this paper.

Abrahams, P.

2002-12-01

202

Functional safety for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

Since inception, the Advanced Technology Solar Telescope (ATST) has planned to implement a facility-wide functional safety system to protect personnel from harm and prevent damage to the facility or environment. The ATST will deploy an integrated safety-related control system (SRCS) to achieve functional safety throughout the facility rather than relying on individual facility subsystems to provide safety functions on an ad hoc basis. The Global Interlock System (GIS) is an independent, distributed, facility-wide, safety-related control system, comprised of commercial off-the-shelf (COTS) programmable controllers that monitor, evaluate, and control hazardous energy and conditions throughout the facility that arise during operation and maintenance. The GIS has been designed to utilize recent advances in technology for functional safety plus revised national and international standards that allow for a distributed architecture using programmable controllers over a local area network instead of traditional hard-wired safety functions, while providing an equivalent or even greater level of safety. Programmable controllers provide an ideal platform for controlling the often complex interrelationships between subsystems in a modern astronomical facility, such as the ATST. A large, complex hard-wired relay control system is no longer needed. This type of system also offers greater flexibility during development and integration in addition to providing for expanded capability into the future. The GIS features fault detection, self-diagnostics, and redundant communications that will lead to decreased maintenance time and increased availability of the facility.

Bulau, Scott; Williams, Timothy R.

2012-09-01

203

Solar tests of aperture plate materials for solar thermal dish collectors  

NASA Technical Reports Server (NTRS)

In parabolic dish solar collectors, walk-off of the spot of concentrated sunlight is a hazard if a malfunction causes the concentrator to stop following the Sun. Therefore, a test program was carried out to evaluate the behavior of various ceramics, metals, and polymers under solar irradiation of about 7000 kW/sq m. (peak) for 15 minutes. The only materials that did not slump or shatter were two grades of medium-grain extruded graphite. High purity, slip-cast silica might be satisfactory at somewhat lower flux. Oxidation of the graphite appeared acceptable during tests simulating walk-off, acquisition (2000 cycles on/off Sun), and spillage (continuous on-Sun operation).

Jaffe, L. D.

1983-01-01

204

ATST telescope pier  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) will be the largest solar telescope in the world with a 4m aperture primary mirror. The off axis nature of the telescope optical layout, has the proportions of an 8 metre class telescope. Accordingly the instrumentation for solar observations a 16m diameter co-rotating laboratory (Coude Rotator) is also located within the telescope pier. The pier has a lower cylindrical profile with an upper conical section to support both the telescope mount with a 9m bearing diameter and contain the 16m diameter Coudé rotator. The performance of this pier cannot be considered in isolation but must account for ancillary equipment, access and initial installation. The Coude rotator structure and bearing system are of similar size to the telescope base structure and therefore this is the proverbial 'ship in a bottle' problem. This paper documents the competing requirements on the pier design and the balancing of these as the design progresses. Also summarized is the evolution of the design from a conceptual traditional reinforced concrete pier to a composite concrete and steel framed design. The stiffness requirements of the steel frame was a unique challenge for both the theoretical performance and overall design strategy considering constructability. The development of design acceptance criteria for the pier is discussed along with interfacing of the AandE firm responsible for the pier design and the telescope designer responsible for the telescope performance.

Jeffers, Paul; Manuel, Eric; Dreyer, Oliver; Kärcher, Hans

2012-09-01

205

Telescopes  

NSDL National Science Digital Library

The first Web site on telescopes comes from Enchanted Learning.com, called Inventions: Telescopes (1). This site gives a brief description of the history of telescopes and their inventors, beginning with Hans Lippershey and his refracting telescope in 1608. The next site, offered by NASA, is the Telescope in Education site (2). This program provides students from around the world the opportunity to use a remotely controlled telescope and charge-coupled device camera in a real-time, hands-on, interactive environment. All of the information needed for educators to set up the program can be found within. The third site, from the online periodical Sky and Telescope, is called Telescopes and Binoculars (3). These how-to links give information on choosing your first telescope, caring for optics, using a map for your telescope, making a backyard observatory, and more. From the Australia Telescope National Facility comes the next site, Australia Telescope Compact Array LIVE! (4). The array is a radio telescope made up of six 22m antennas whose locational and other information is updated every ten seconds on the site. Telescope images and links to other similar sites can also be found here. The next site, from the National Optical Astronomy Observatory, is the Kitt Peak Virtual Tour (5). The Kitt Peak National Observatory is the first national observatory of the United States and has the world's largest collection of optical telescopes. The site gives a complete tour of the grounds and telescopes, along with descriptions, maps, photographs, and more. The Space Telescope Science Institute's Web site, Hubble Space Telescope Public Pictures (6), provides a large database of space photographs and press releases regarding Hubble. The extraordinary pictures are categorized by subject and the press releases by year (which also contain relevant photographs). The next site from the Sloan Digital Sky Survey called Image Gallery: Telescope Photos (7) contains pictures not of what the telescopes are viewing but of the telescopes themselves. The short descriptions and impressive photographs give unfamiliar users an idea of what these machines actually look like. The last site, Telescope Data Center (8), is maintained by the Smithsonian Astrophysical Observatory, which is part of the Harvard-Smithsonian Center for Astrophysics. The Data Center supports scheduling, observation, data reduction, analysis, and data archiving for the optical telescopes, and offers these products on the site for anyone interested.

Brieske, Joel A.

206

The enclosure for the European Solar Telescope (EST) F.C.M. Bettonvil*a  

E-print Network

the requirements. Keywords: Dome, solar telescope, CFD, local seeing, turbulence, kinetic energy, retractable of the plasma over many scale heights. EST will be located on the Canary Islands, at either La Palma or Tenerife

Rutten, Rob

207

A two-dimensional spectropolarimeter as a first-light instrument for the Daniel K. Inouye Solar Telescope  

NASA Astrophysics Data System (ADS)

The Visible Tunable Filter (VTF) is a narrowband tunable filter system for imaging spectropolarimetry. The instrument will be one of the first-light instruments of the Daniel K. Inouye Solar Telescope (DKIST) that is currently under construction on Maui (Hawaii). The DKIST has a clear aperture of 4 meters. The VTF is being developed by the Kiepenheuer Institut für Sonnenphysik in Freiburg, as a German contribution to the DKIST. The VTF is designed as a diffraction-limited narrowband tunable instrument for Stokes spectro-polarimetry in the wavelength range between 520 and 860 nm. The instrument uses large-format Fabry-Perot interferometers (Etalons) as tunable monochromators with clear apertures of about 240 mm. To minimize the influence of gravity on the interferometer plates, the Fabry-Perots are placed horizontally. This implies a complex optical design and a three-dimensional support structure instead of a horizontal optical bench. The VTF has a field of view of one arc minute squared. With 4096x4096 pixel detectors, one pixel corresponds to an angle of 0.014" on the sky (10 x 10 km on the Sun). The spectral resolution is 6 pm at a wavelength of 600 nm. One 2Dspectrum with a polarimetric sensitivity of 5E-3 will be recorded within 13 seconds. The wavelength range of the VTF includes a number of important spectral lines for the measurement flows and magnetic fields in the atmosphere of the Sun. The VTF uses three identical large-format detectors, two for the polarimetric measurements, and one for broadband filtergrams. The main scientific observables of the VTF are Stokes polarimetric images to retrieve the magnetic field configuration of the observed area, Doppler images to measure the line-of-sight flow in the solar photosphere, and monochromatic intensity filtergrams to study higher layers of the solar atmosphere.

Schmidt, Wolfgang; Bell, Alexander; Halbgewachs, Clemens; Heidecke, Frank; Kentischer, Thomas J.; von der Lühe, Oskar; Scheiffelen, Thomas; Sigwarth, Michael

2014-07-01

208

WILL THE LARGE SYNOPTIC SURVEY TELESCOPE DETECT EXTRA-SOLAR PLANETESIMALS ENTERING THE SOLAR SYSTEM?  

SciTech Connect

Planetesimal formation is a common by-product of the star formation process. Taking the dynamical history of the solar system as a guideline-in which the planetesimal belts were heavily depleted due to gravitational perturbation with the giant planets-and assuming similar processes have taken place in other planetary systems, one would expect the interstellar space to be filled with extra-solar planetesimals. However, not a single one of these objects has been detected so far entering the solar system, even though it would clearly be distinguishable from a solar system comet due to its highly hyperbolic orbit. The Large Synoptic Survey Telescope (LSST) will provide wide coverage maps of the sky to a very high sensitivity, ideal to detect moving objects like comets, both active and inactive. In anticipation of these observations, we estimate how many inactive 'interstellar comets' might be detected during the duration of the survey. The calculation takes into account estimates (from observations and models) of the number density of stars, the amount of solids available to form planetesimals, the frequency of planet and planetesimal formation, the efficiency of planetesimal ejection, and the possible size distribution of these small bodies.

Moro-Martin, Amaya [Centro de AstrobiologIa (CSIC-INTA), 28850 Torrejon de Ardoz, Madrid (Spain); Turner, Edwin L. [Princeton University Observatory, Princeton, NJ 08544 (United States); Loeb, Abraham [Harvard University, Center for Astrophysics, MS 51, 60 Garden Street, Cambridge, MA 02138 (United States)

2009-10-10

209

Kees Zwaan, open principle, future of high-resolution solar telescopes  

NASA Astrophysics Data System (ADS)

It was around the 1970s that during site-test campaigns masts were erected up till 30 m height with sensors at several heights for the measurement of temperature fluctuations. Kees Zwaan discovered that the fluctuations decrease drastically at heights from about 15 m and upward when there is some wind. The conclusion from this experience was the open telescope principle: a telescope completely free in the air 15 m or more above the ground. The Dutch Open Telescope (DOT) was the pioneering demonstrator of the open-telescope technology. Now that larger high-resolution telescopes come in view, it is time to analyze again the principle: the essentials for proper working of the open principle and the design consequences for the new generation of high-resolution solar telescopes.

Hammerschlag, R. H.; Bettonvil, F. C. M.

2013-01-01

210

Data From the Precision Solar Photometric Telescope (Pspt) in Hawaii From March 1998 to March 1999  

Microsoft Academic Search

Two Precision Solar Photometric Telescopes (PSPT) designed and built at the U.S. National Solar Observatory (NSO) are in operation in Rome and Hawaii. A third PSPT is now in operation the NSO at Sunspot, NM. The PSPT system records full disk solar images at three wavelengths: K line at 393.3 nm and two continua at 409 nm and 607 nm throughout the observing

Oran R. White; Peter A. Fox; Randy Meisner; Mark P. Rast; Eric Yasukawa; Darryl Koon; Crystal Rice; Haosheng Lin; Jeff Kuhn; Roy Coulter

2000-01-01

211

Data from the Precision Solar Photometric Telescope (PSPT) in Hawaii from March 1998 to March 1999  

Microsoft Academic Search

\\u000a Two Precision Solar Photometric Telescopes (PSPT) designed and built at the U.S. National Solar Observatory (NSO) are in operation\\u000a in Rome and Hawaii. A third PSPT is now in operation the NSO at Sunspot, NM. The PSPT system records full disk solar images\\u000a at three wavelengths: K line at 393.3 nm and two continua at 409 nm and 607 nm

Oran R. White; Peter A. Fox; Randy Meisner; Mark P. Rast; Eric Yasukawa; Koon Darryl; Crystal Rice; Haosheng Lin; Jeff Kuhn; Roy Coulter

212

The 1.6 m off-axis New Solar Telescope (NST) in Big Bear  

NASA Astrophysics Data System (ADS)

The 1.6-m New Solar Telescope (NST) has been used to observe the Sun for more than three years with ever increasing capabilities as its commissioning phase winds down. The NST is the first facility-class solar telescope built in the U.S. in a generation, and it has an off-axis design as is planned for the 4 m Advanced Technology Solar Telescope. Lessons learned will be discussed. Current NST post-focus instrumentation includes adaptive optics (AO) feeding photometric and near-IR polarimetric sytems, as well as an imaging spectrograph. On-going instrumentation projects will be sketched, including Multi-Conjugate AO (MCAO), next generation (dual Fabry- Perot) visible light and near-IR polarimeters and a fully cryogenic spectrograph. Finally, recent observational results illustrating the high resolution capabilities of the NST will be shown.

Goode, Philip R.; Cao, Wenda

2012-09-01

213

Paraboloidal X-ray telescope mirror for solar coronal spectroscopy  

NASA Technical Reports Server (NTRS)

The telescope mirror for the X-ray Spectrograph Spectrometer Telescope System is a sixty degree sector of an extreme off-axis paraboloid of revolution. It was designed to focus a coronal region 1 by 10 arc seconds in size on the entrance slit of the spectrometer after reflection from the gold surface. This paper discusses the design, manufacture, and metrology of the mirror, the methods of precision mechanical metrology used to focus the system, and the mounting system which locates the mirror and has proven itself through vibration tests. In addition, the results of reflection efficiency measurements, alignment tolerances, and ray trace analysis of the effects of misalignment are considered.

Brown, W. A.; Bruner, E. C., Jr.; Acton, L. W.; Franks, A.; Stedman, M.; Speer, R. J.

1979-01-01

214

Science drivers and requirements for an Advanced Technology Large Aperture Space Telescope (ATLAST): implications for technology development and synergies with other future facilities  

NASA Astrophysics Data System (ADS)

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astronphysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers that define the main performance requirements for ATLAST (8 to 16 milliarcsec angular resolution, diffraction limited imaging at 0.5 ?m wavelength, minimum collecting area of 45 square meters, high sensitivity to light wavelengths from 0.1 ?m to 2.4 ?m, high stability in wavefront sensing and control). We will also discuss the synergy between ATLAST and other anticipated future facilities (e.g., TMT, EELT, ALMA) and the priorities for technology development that will enable the construction for a cost that is comparable to current generation observatory-class space missions.

Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Philip; Tumlinson, Jason; Mountain, Matt; Soummer, Rémi; Hyde, Tupper

2010-07-01

215

Review of the Solar Array Telescopes David A. Smith  

E-print Network

, solar tower facilities were built in several countries to generate electricity, or as high temperature, high heat research facilities. Their gigantic mirror areas, on hundreds, even thousands, of alt that of the Cherenkov imaging tele- scopes have been the "solar tower" detectors. They use > 2000 m2 mirror areas

Paris-Sud XI, Université de

216

ATST telescope mount: telescope of machine tool  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

217

Active reconstruction and alignment strategies for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) is a 4m off-axis telescope with a Gregorian front end. At the time of its construction it will be the world's largest solar astronomical telescope. During scientific operations the ATST mirrors and structure will be deformed due to thermal and gravitational loading. The ATST team has developed a quasi-static alignment scheme that utilizes the wavefront sensing signals from at least one and as many as three wavefront sensors in the telescope science field of view, and active figure control of the primary mirror and rigid body control of the secondary mirror to achieve least-squares optical control of the telescope. This paper presents the quasi-static alignment model for the ATST, and three different active alignment schemes that are the damped least-squares control, force optimized control that defines a least-squares aligned state of the telescope subject to minimum primary actuator force, and pivot-point control of the secondary mirror. All three strategies achieve the desired minimum RMS wavefront error, but demonstrate different optimized states of the telescope.

Upton, Robert; Rimmele, Thomas

2010-08-01

218

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

NASA Technical Reports Server (NTRS)

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.

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

219

The Large Millimeter Telescope and Solar Like Stars  

NASA Astrophysics Data System (ADS)

This paper describes the current status of the Large Millimeter Telescope (LMT), the near-term plans for the telescope and the initial suite of instrumentation. It also briefly describes two astronomical branches in which the LMT will certainly have a major impact: the study of thermal emission of circumstellar material around main sequence stars and the analysis of the molecular contents of this material in relatively young stars. The LMT is a bi-national collaboration between Mexico and the USA, led by the Instituto Nacional de Astrofísica, Optica y Electrónica (INAOE) and the University of Massachusetts at Amherst, to construct, commission and operate a 50m-diameter millimeter-wave radio telescope. Construction of the telescope structure is complete at the 4600 m LMT site on the summit of Volcán Sierra Negra, an extinct volcano in the Mexican state of Puebla. First-light with the LMT was successfully conducted in June and July 2011 with observations at both 3 and 1.1 mm. The commissioning and future scientific operation of the LMT is divided into two major phases. As part of phase I, following the improvement in the alignment of the surface segments within the inner 32 meter diameter of the antenna, the project will begin the first shared risk scientific observations in the spring of 2013. In phase II, we will continue the installation and alignment of the remainder of the reflector surface, after which the final commissioning of the full 50m LMT will take place. The LMT antenna, outfitted with its initial complement of scientific instruments, will be a world-leading scientific research facility for millimeter-wave astronomy.

Chavez, M.; Hughes, D.; LMT Project Team

2013-04-01

220

The daytime use of Adaptive Optics for solar and stellar Extremely Large Telescopes  

Microsoft Academic Search

Now Single Conjugate Adaptive Optics (SCAO) has been successfully implemented on both nighttime and solar telescopes, there is a rapidly growing interest in developing, what will be the next step in astronomical adaptive optics, Multi-Conjugate Adaptive Optics (MCAO). MCAO aims at breaking the small field-of-view barrier inherent in SCAO. MCAO is considered an essential component for both future solar and

Jacques Beckers

2002-01-01

221

The Soft X-ray Telescope for the SOLAR-A mission  

Microsoft Academic Search

The Soft X-ray Telescope (SXT) of the SOLAR-A mission is designed to produce X-ray movies of flares with excellent angular and time resolution as well as full-disk X-ray images for general studies. A selection of thin metal filters provide a measure of temperature discrimination and aid in obtaining the wide dynamic range required for solar observing. The co-aligned SXT aspect

S. Tsuneta; L. Acton; M. Bruner; J. Lemen; W. Brown; R. Caravalho; R. Catura; S. Freeland; B. Jurcevich; M. Morrison; Y. Ogawara; T. Hirayama; J. Owens

1991-01-01

222

OSCILLATORY BEHAVIOR IN THE QUIET SUN OBSERVED WITH THE NEW SOLAR TELESCOPE  

SciTech Connect

Surface photometry of the quiet Sun has achieved an angular resolution of 0.''1 with the New Solar Telescope at Big Bear Solar Observatory, revealing that a disproportionate fraction of the oscillatory events appear above observed bright point-like structures. During the tracking of these structures, we noted that the more powerful oscillatory events are cospatial with them, indicating that observed flux tubes may be the source of many observed oscillatory events.

Andic, A.; Goode, P. R.; Cao, W.; Yurchyshyn, V.; Abramenko, V. [Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States); Chae, J.; Ahn, K. [Also at Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-741 (Korea, Republic of)

2010-07-10

223

The Siberian Solar Radio Telescope: the current state of the instrument, observations, and data  

Microsoft Academic Search

The Siberian Solar Radio Telescope (SSRT) is one of the world's largest solar radio heliographs. It commenced operation in\\u000a 1983, and since then has undergone several upgrades. The operating frequency of the SSRT is 5.7 GHz. Since 1992 the instrument\\u000a has had the capability to make one-dimensional scans with a high time resolution of 56 ms and an angular resolution of 15 arc sec.

V. V. Grechnev; S. V. Lesovoi; G. Ya. Smolkov; B. B. Krissinel; V. G. Zandanov; A. T. Altyntsev; N. N. Kardapolova; R. Y. Sergeev; A. M. Uralov; V. P. Maksimov; B. I. Lubyshev

2003-01-01

224

Performance of polarization modulation and calibration optics for the Daniel K. Inouye Solar Telescope  

NASA Astrophysics Data System (ADS)

The Daniel K. Inouye Solar Telescope (formerly Advanced Technology Solar Telescope) will be the world's largest solar telescope and polarimeter when completed in 2019. Efficient use of the telescope to address key science priorities calls for polarization measurements simultaneously over broad wavelength ranges and calibration of the telescope and polarimeters to high accuracy. Broadband polarization modulation and calibration optics utilizing crystal optics have been designed for this application. The performance of polarization modulators and calibration retarders is presented along with a discussion of the unique challenges of this application. Polarimeters operate over the ranges of 0.38-1.1 microns, 0.5-2.5 microns, and 1.0-5.0 microns. Efficient polarization modulation over these broad ranges led to modulators utilizing multiple wave plates and that are elliptical, rather than linear, retarders. Calibration retarders are linear retarders and are constructed from the same sub-component wave plate pairs as the polarization modulators. Polarization optics must address efficiency over broad wavelength ranges while meeting beam deflection, transmitted wave front error, and thermal constraints and doing so with designs that, though large in diameter, can be affordably manufactured.

Elmore, David F.; Sueoka, Stacey R.; Casini, Roberto

2014-07-01

225

The Calibration of the Solar-B X-ray Telescope (XRT)  

NASA Astrophysics Data System (ADS)

The Solar-B X-ray telescope (XRT) is designed to have a wide temperature sensitivity in order to observe and analyze both the high (5-10 MK) and low temperature (1-5 MK) phenomena in the coronal plasma. It will be the telescope with the highest resolution ever flown for solar coronal studies. The telescope is designed for full Sun imaging over the wavelength range 6-60 Angstroms. The XRT is a grazing-incidence modified Wolter I X-ray telescope, of 35 cm inner diameter and 2.7 m focal length. The 2048 X 2048 back illuminated CCD has 13.5 µm pixels, corresponding to 1 arcsecond. The filter set used in the XRT, mounted at the telescope entrance and near the focal plane, will perform three functions: (1) to reduce the heat load inside the telescope, (2) to reduce the incoming visible light and (3) to provide spectral diagnostics to determine coronal plasma temperatures. This paper will present the results of the XRT calibration performed at the X-ray Calibration Facility, NASA-MSFC, Huntsville, Alabama in January 2005. We will discuss the methods and the most significant results of the XRT performance, namely: imaging properties, encircled energy, the point response function and the effective area in the 0.2-2 keV energy range.

Golub, L.; Barbera, M.; Bookbinder, J.; Cheimets, P.; Cirtain, J.; Cosmo, M.; Deluca, E.; Podgorski, W.; Sette, A.; Varisco, S.; Weber, M.

2005-05-01

226

High-resolution telescope and spectrograph observations of the quiet solar chromosphere and transition zone  

Microsoft Academic Search

A systematic program to observe the two-dimensional structure of the solar atmosphere and its temporal variation was conducted in connection with the third rocket flight of the High Resolution Telescope and Spectrograph (HRTS). A description is presented of the manner in which line intensities, Doppler shifts (velocities), and line widths are obtained from HRTS spectra. These quantities are derived for

K. P. Dere; J.-D. F. Bartoe; G. E. Brueckner

1984-01-01

227

Exploring the Solar System, the Galaxies, and the Universe with the Hubble Space Telescope  

NSDL National Science Digital Library

The Hubble Telescope site (http://hubblesite.org) contains numerous teaching tools including videos, news articles about the solar system and the Universe, and games that introduce and reinforce astronomy and space science content and concepts. Teachers can design activities for multiple grade levels using the site as a foundation.

Rebecca Dodge

228

Solar Physics, Space Weather, and Wide-field X-ray Telescopes  

E-print Network

Solar Physics, Space Weather, and Wide-field X-ray Telescopes CREOL & FPCE: The College of Optics at CREOL Industrial Affiliates Day "Optics & Photonics for Space-Based and Medical Applications" April 21, 2006 #12;Abstract The sun is essentially a giant thermonuclear fusion reactor (105 x the size

Van Stryland, Eric

229

On the Use of Cherenkov Telescopes for Outer Solar System Body Occultations  

E-print Network

Imaging Atmosphere Cherenkov Telescopes (IACT) are arrays of very large optical telescopes that are well-suited for rapid photometry of bright sources. I investigate their potential in observing stellar occultations by small objects in the outer Solar System, Transjovian Objects (TJOs). These occultations cast diffraction patterns on the Earth. Current IACT arrays are capable of detecting objects smaller than 100 meters in radius in the Kuiper Belt and 1 km radius out to 5000 AU. The future Cherenkov Telescope Array (CTA) will have even greater capabilities. Because the arrays include several telescopes, they can potentially measure the speeds of TJOs without degeneracies, and the sizes of the TJOs and background stars. I estimate the achievable precision using a Fisher matrix analysis. With CTA, the precisions of these parameter estimations will be as good as a few percent. I consider how often IACTs can observe occultations by members of different TJO populations, including Centaurs, Kuiper Belt Objects (KB...

Lacki, Brian C

2014-01-01

230

Quasi-static wavefront control for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) requires active control of quasi-static telescope aberrations in order to meet image quality standards set by its science requirements. Wavefront control is managed by the Telescope Control System, with many telescope subsystems playing key roles. We present the design of the ATST quasi-static wavefront and alignment control architecture and the algorithms used to control its four active mirrors. Two control algorithms are presented, one that minimizes force on M1 actuators and another that employs a neutral-pointing constraint on M2 to reduce pointing error. We also present simulations that generate typical daily active mirror trajectories which correct optical misalignments due to changing gravitational and thermal loads.

Johnson, Luke C.; Upton, R.; Rimmele, T.; Barden, S.

2012-09-01

231

Solar observations with a low frequency radio telescope  

NASA Astrophysics Data System (ADS)

We have set up a low frequency radio monitoring station for solar bursts at the Observatory of the Aristotle University in Thessaloniki. The station consists of a dual dipole phased array, a radio receiver and a dedicated computer with the necessary software installed. The constructed radio receiver is based on NASA's Radio Jove project. It operates continuously, since July 2010, at 20.1 MHz (close to the long-wavelength ionospheric cut-off of the radio window) with a narrow bandwidth (~5 kHz). The system is properly calibrated, so that the recorded data are expressed in antenna temperature. Despite the high interference level of an urban region like Thessaloniki (strong broadcasting shortwave radio stations, periodic experimental signals, CBs, etc), we have detected several low frequency solar radio bursts and correlated them with solar flares, X-ray events and other low frequency solar observations. The received signal is monitored in ordinary ASCII format and as audio signal, in order to investigate and exclude man-made radio interference. In order to exclude narrow band interference and calculate the spectral indices of the observed events, a second monitoring station, working at 36 MHz, is under construction at the village of Nikiforos near the town of Drama, about 130 km away of Thessaloniki. Finally, we plan to construct a third monitoring station at 58 MHz, in Thessaloniki. This frequency was revealed to be relatively free of interference, after a thorough investigation of the region.

Myserlis, I.; Seiradakis, J.; Dogramatzidis, M.

2012-01-01

232

Harnessing solar pressure to slew and point large infrared space telescopes  

NASA Astrophysics Data System (ADS)

Large astronomical Gossamer telescopes in space will need to employ large solar shields to safeguard the optics from solar radiation. These types of telescopes demand accurate controls to maintain telescope pointing over long integration periods. We propose an active solar shield system that harnesses radiation pressure to accurately slew and acquire new targets without the need for reaction wheels or thrusters. To provide the required torques, the solar shield is configured as an inverted, 4-sided pyramidal roof. The sloped roof interior surfaces are covered with hinged “tiles” made from piezoelectric film bimorphs with specular metallized surfaces. Nominally, the tiles lie flat against the roof and the sunlight is reflected outward equally from all sloped surfaces. However, when the tiles on one roof pitch are raised, the pressure balance is upset and the sunshade is pushed to one side. By judicious selection of the tiles and control of their lift angle, the solar pressure can be harvested to stabilize the spacecraft orientation or to change its angular momentum. A first order conceptual design performance analysis and the results from the experimental design, fabrication and testing of piezoelectric bimorph hinge elements will be presented. Next phase challenges in engineering design, materials technology, and systems testing will be discussed.

Errico, Simona; Angel, Roger P.; Calvert, Paul D.; Woof, Neville

2003-03-01

233

The x-ray/EUV telescope for the Solar-C mission: science and development activities  

NASA Astrophysics Data System (ADS)

We report science and development activities of the X-ray/EUV telescope for the Japanese Solar-C mission whose projected launch around 2019. The telescope consists of a package of (a) a normal-incidence (NI) EUV telescope and (b) a grazing-incidence (GI) soft X-ray telescope. The NI telescope chiefly provides images of low corona (whose temperature 1 MK or even lower) with ultra-high angular resolution (0.2-0.3"/pixel) in 3 wavelength bands (304, 171, and 94 angstroms). On the other hand, the GI telescope provides images of the corona with a wide temperature coverage (1 MK to beyond 10 MK) with the highest-ever angular resolution (~0.5"/pixel) as a soft X-ray coronal imager. The set of NI and GI telescopes should provide crucial information for establishing magnetic and gas-dynamic connection between the corona and the lower atmosphere of the Sun which is essential for understanding heating of, and plasma activities in, the corona. Moreover, we attempt to implement photon-counting capability for the GI telescope with which imaging-spectroscopy of the X-ray corona will be performed for the first time, in the energy range from ~0.5 keV up to 10 keV. The imaging-spectroscopic observations will provide totally-new information on mechanism(s) for the generation of hot coronal plasmas (heated beyond a few MK), those for magnetic reconnection, and even generation of supra-thermal electrons associated with flares. An overview of instrument outline and science for the X-ray photoncounting telescope are presented, together with ongoing development activities in Japan towards soft X-ray photoncounting observations, focusing on high-speed X-ray CMOS detector and sub-arcsecond-resolution GI mirror.

Sakao, Taro; Narukage, Noriyuki; Imada, Shinsuke; Suematsu, Yoshinori; Shimojo, Masumi; Tsuneta, Saku; DeLuca, Edward E.; Watanabe, Kyoko; Ishikawa, Shin-nosuke

2012-09-01

234

Commissioning and First Operation of the Cryogenics for the CERN Axion Solar Telescope (CAST)  

SciTech Connect

A new experiment, the CERN Axion Solar Telescope (CAST) was installed and commissioned in 2002. Its aim is to experimentally prove the existence of an as yet hypothetical particle predicted by theory as a solution of the strong CP problem and possible candidate for galactic dark matter. The heart of the detector consists of a decommissioned 10-m long LHC superconducting dipole prototype magnet, providing a magnetic field of up to 9.5 T. The whole telescope assembly is aligned with high precision to the core of the sun. If they exist, axions could be copiously produced in the core of the sun and converted into photons within the transverse magnetic field of the telescope. The converted low-energy solar axion spectrum, peaked around a mean energy of 4.4 keV, can then be focused by a special x-ray mirror system and detected by low-background photon detectors, installed on each end of the telescopes twin beam pipes. This paper describes the external and proximity cryogenic system and magnet commissioning as well as the first operational experience with the overall telescope assembly.

Barth, K.; Delikaris, D.; Passardi, G.; Pezzetti, M.; Pirotte, O.; Stewart, L.; Vullierme, B.; Walckiers, L.; Zioutas, K. [CERN - European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland)

2004-06-23

235

The Lowell ``Solar Variations" Telescope: 50 Years of Continuous Service to Planetary and Stellar Research  

NASA Astrophysics Data System (ADS)

The return of Harold L. Johnson to Lowell Observatory in 1952 marked the beginning of a half century of precise photoelectric photometry using a new 21-inch reflecting telescope that remains in service today. A 1953 newspaper headline proclaimed ``Lowell's New Telescope to Train on Sun's Light," a somewhat misleading description that nevertheless captures the spirit of work carried out over the past half century. Johnson completed observations defining the UBV system and began regular measurements of Uranus and Neptune in a long-running effort to characterize solar variability by monitoring reflected planetary light. Although spacecraft measurements after 1980 show that the Sun's variation is less than 0.1% and thus undetectable from the ground, the ``Solar Variability" theme motivated long-term studies of the variations of sunlike stars and solar system objects. Perhaps the telescope's most enduring contribution has been to supply data characterizing the sub-1% variability of sunlike stars and the power law relationship between photometric variability and mean chromospheric activity. We illustrate the output of this highly productive facility with a sampling of results from the past half century, including 50-year lightcurves of Uranus and Neptune, a 29.5 year complete seasonal lightcurve of Titan, lightcurves of sunlike stars (now being extended into a third decade by automated telescopes at Fairborn Observatory), and shorter term projects on hot main sequence pulsators. It is unlikely that these projects would have been deemed feasible without guaranteed, uninterrupted, and convenient access to a dedicated telescope. Work described here has been supported almost without interruption by the NSF Solar-Terrestrial program, NASA Planetary Astronomy, and the United States Air Force.

Lockwood, G. W.; Jerzykiewicz, M.

2005-12-01

236

Thermal effects in the Solar Disk Sextant telescope  

NASA Astrophysics Data System (ADS)

The Solar Disk Sextant (SDS) is an instrument conceived to monitor the diameter of the Sun and its oscillations. A key component of the SDS is the Beam Splitting Wedge (BSW), whose function is to provide calibration to the geometry of the focal plane. The thermal behavior of the BSW is critical, as it affects the overall performance of the instrument. Modeling the elements of the BSW and the basic thermal processes is shown to account for experimental evidences of defocusing observed in early measurements with a balloon borne prototype. Basic requirements for accurate thermal stabilization on board of the final instrument are derived.

Spagnesi, Chiara; Vannoni, Maurizio; Molesini, Giuseppe; Righini, Alberto

2004-02-01

237

Grazing-incidence telescope-spectrograph for space solar-imaging spectroscopy.  

PubMed

The design of a stigmatic grazing-incidence instrument for space applications to solar-imaging spectroscopy is presented. It consists of a double telescope and a spectrograph: Telescope I consists of a single cylindrical mirror with parabolic section, focusing the radiation on the entrance slit of the spectrograph in the spectral dispersion plane; telescope II consists of two cylindrical mirrors with aspherical section in a Wolter configuration, focusing the radiation on the spectrograph focal plane in the direction perpendicular to the spectral dispersion plane. The spectrograph consists of a grazing-incidence spherical variable-line-spaced grating with flat-field properties. Telescope II is crossed with respect to the grating and telescope I; i.e., it is mounted with its tangential planes coincident with the grating equatorial plane. The spectrum is acquired by a detector mounted at near-normal incidence with respect to the direction of the exit beam. The spectral resolution is also preserved for off-axis angles. The effective collecting area of the instrument can be preserved by adoption of a nested configuration for telescope II without degradation of the spectral resolution. PMID:18357295

Poletto, L; Tondello, G

2001-06-01

238

Measurement of solar vector magnetic fields using Kodaikanal tower telescope  

NASA Astrophysics Data System (ADS)

A Stokes polarimeter was built at the Kodaikanal Tower Telescope to study the vector field map of active regions like sunspot using the well known Fe I lines 6301.5 Ĺ and 6302.5 Ĺ lines. The Mueller matrix of the polarimeter was obtained using simple laboratory and field tests. The instrumental polarisation due to the oblique reflections are removed before the observed Stokes profiles were analysed. The advanced Stokes Polarimeter data analysis program (ASP code) was used to invert the corrected Stokes profiles to calculate the vector magnetic field parameters of NOAA 8951. The maximum field strength obtained at the umbra of the sunspot was 2500 Gauss. The variation of the field strength, the line-of-sight angle and the azimuthal angle along a cut which passes through the umbra resembles that of a simple round sunspot. The accuracy in the calculation of the vector field is high in the umbra and low in the outer edge of the penumbra of the observed sunspot. The range of errors in the calculation of the field strength, line-of-sight inclination angle, and the azimuthal angle of the magnetic vector are 20-100 Gauss, 1-5O, and 12-20O respectively. We also find a good fit for the observed Stokes profiles of the Ti I line at 6303.78 Ĺ with a synthetic profile produced using the vector field parameters derived from the Fe I 6301.5 Ĺ and 6302.5 Ĺ lines.

Sankarasubramanian, R.; Rangarajan, K. E.; Ramesh, K. B.

2002-06-01

239

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: A 4 sq. deg Galactic Plane Survey in Vulpecula (l=59)  

E-print Network

We present the first results from a new 250, 350, and 500 micron Galactic Plane survey taken with the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) in 2005. This survey's primary goal is to identify and characterize high-mass proto-stellar objects (HMPOs). The region studied here covers 4 sq. deg near the open cluster NGC 6823 in the constellation Vulpecula (l=59). We find 60 compact sources (0) velocities combined with a variety of other velocity and morphological data in the literature. In total, 49 sources are associated with a molecular cloud complex encompassing NGC 6823 (distance ~2.3kpc), 10 objects with the Perseus Arm (~8.5kpc) and one object is probably in the outer Galaxy (~14kpc). Near NGC 6823, the inferred luminosities and masses of BLAST sources span ~40-10^4 L_\\odot, and ~15-700 M_\\odot, respectively. The mass spectrum is compatible with molecular gas masses in other high-mass star forming regions. Several luminous sources appear to be Ultra Compact HII regions powered by early B stars. However, many of the objects are cool, massive gravitationally-bound clumps with no obvious internal radiation from a protostar, and hence excellent HMPO candidates.

E. L. Chapin; P. A. R. Ade; J. J. Bock; C. Brunt; M. J. Devlin; S. Dicker; M. Griffin; J. O. Gundersen; M. Halpern; P. C. Hargrave; D. H. Hughes; J. Klein; G. Marsden; P. G. Martin; P. Mauskopf; C. B. Netterfield; L. Olmi; E. Pascale; G. Patanchon; M. Rex; D. Scott; C. Semisch; M. D. P. Truch; C. Tucker; G. S. Tucker; M. P. Viero; D. V. Wiebe

2007-11-21

240

Gregor@night: The future high-resolution stellar spectrograph for the GREGOR solar telescope  

NASA Astrophysics Data System (ADS)

We describe the future night-time spectrograph for the GREGOR solar telescope and present its science core projects. The spectrograph provides a 3-pixel resolution of up to R=87 000 in 45 échelle orders covering the wavelength range 390-900 nm with three grating settings. An iodine cell can be used for high-precision radial velocity work in the 500-630 nm range. The operation of the spectrograph and the telescope will be fully automated without the presence of humans during night-time and will be based on the successful STELLA control system. Future upgrades include a second optical camera for even higher spectral resolution, a Stokes-V polarimeter and a link to the laser-frequency comb at the Vacuum Tower Telescope. The night-time core projects are a study of the angular-momentum evolution of ``The Sun in Time'' and a continuation of our long-term Doppler imaging of active stars.

Strassmeier, K. G.; Ilyin, I. V.; Woche, M.; Granzer, T.; Weber, M.; Weingrill, J.; Bauer, S.-M.; Popow, E.; Denker, C.; Schmidt, W.; von der Lühe, O.; Berdyugina, S.; Collados, M.; Koubsky, P.; Hackman, T.; Mantere, M. J.

2012-11-01

241

The solar array-induced disturbance of the Hubble Space Telescope pointing system  

NASA Technical Reports Server (NTRS)

The investigation of the vibrational disturbances of the Hubble Space Telescope that were discovered soon after deployment in orbit is described in detail. It was found that the disturbances were particularly evident during orbital day-night crossings, and that the magnitudes of the disturbances were considerably larger than the design jitter requirements. This paper describes the process by which the vibrations were characterized and isolated to a particular mechanism. The analysis of the flight data and comparisons with computer simulation results showed that the source of the disturbances was the thermally driven deformation of the solar arrays in conjunction with frictional effects in the array mechanisms. The control system was successfully modified to attenuate the disturbances to tolerable levels pending mechanical and thermal redesign of the solar arrays. The new arrays were installed during the first space telescope servicing mission and, in combination with the enhanced control system algorithm, reduced the disturbances to satisfactory levels.

Foster, C. L.; Tinker, M. L.; Nurre, G. S.; Till, W. A.

1995-01-01

242

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

NASA Technical Reports Server (NTRS)

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.

Jenkins, Kathleen; Hershfeld, Donald J.

1999-01-01

243

X-ray photographs of a solar active region with a multilayer telescope at normal incidence  

NASA Technical Reports Server (NTRS)

An astronomical photograph was obtained with a multilayer X-ray telescope. A 4-cm tungsten-carbon multilayer mirror was flown as part of an experimental solar rocket payload, and successful images were taken of the sun at normal incidence at a wavelength of 44 A. Coronal Si XII emission from an active region was recorded on film; as expected, the structure is very similar to that observed at O VIII wavelengths by the Solar Maximum Mission flat-crystal spectrometer at the same time. The small, simple optical system used in this experiment appears to have achieved a resolution of 5 to 10 arcsec.

Underwood, J. H.; Bruner, M. E.; Haisch, B. M.; Brown, W. A.; Acton, L. W.

1987-01-01

244

Features of the solar array drive mechanism for the space telescope  

NASA Technical Reports Server (NTRS)

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.

Hostenkamp, R. G.

1985-01-01

245

Multiple field-of-view MCAO for a Large Solar Telescope: LOST simulations  

E-print Network

In the framework of a 4m class Solar Telescope we studied the performance of the MCAO using the LOST simulation package. In particular, in this work we focus on two different methods to reduce the time delay error which is particularly critical in solar adaptive optics: a) the optimization of the wavefront reconstruction by reordering the modal base on the basis of the Mutual Information and b) the possibility of forecasting the wavefront correction through different approaches. We evaluate these techniques underlining pros and cons of their usage in different control conditions by analyzing the results of the simulations and make some preliminary tests on real data.

Stangalini, Marco; Del Moro, Dario; Piazzesi, Roberto

2010-01-01

246

The chemistry of micrometeoroid and space debris remnants captured on hubble space telescope solar cells  

Microsoft Academic Search

Prior to the retrieval in 1993 from low Earth orbit (LEO), the “—V2” Solar Array wing of the Hubble Space Telescope was exposed to hypervelocity impacts (micrometre to millimetre scale) from both micrometeoroids and space debris. The initial survey of the damage (100–3500?m diameter sized craters) identified that micrometeoroid remnants dominated the flux in the 100–1000?m size regime, with debris

G. A. Graham; N. McBride; A. T. Kearsley; G. Drolshagen; S. F. Green; J. A. M. McDonnell; M. M. Grady; I. P. Wright

2001-01-01

247

Background study for the pn-CCD detector of CERN Axion Solar Telescope  

Microsoft Academic Search

The CERN Axion Solar Telescope (CAST) experiment searches for axions from the Sun converted into photons with energies up to around 10keV via the inverse Primakoff effect in the high magnetic field of a superconducting Large Hadron Collider (LHC) prototype magnet. A backside illuminated pn-CCD detector in conjunction with an X-ray mirror optics is one of the three detectors used

S. Cebrián; A. Rodríguez; M. Kuster; B. Beltrán; H. Gómez; R. Hartmann; I. G. Irastorza; R. Kotthaus; G. Luzón; J. Morales; J. Ruz; L. Strüder; J. A. Villar

2007-01-01

248

Keck Observations of Solar System Objects: Perspectives for Extremely Large Telescopes  

Microsoft Academic Search

From differential tracking techniques, required for appulse observations of KBOs with Laser Guide Star Adaptive Optics (LGSAO),\\u000a to developing methods for collecting spectra at the precise moment of a predicted impact, each Solar System observation conducted\\u000a on a large telescope presents a unique set of challenges. We present operational details and some key science results from\\u000a our science program, adaptive

A. R. Conrad; R. W. Goodrich; R. D. Campbell; W. J. Merline; J. D. Drummond; C. Dumas; B. Carry

2009-01-01

249

MuSICa image slicer prototype at 1.5-m GREGOR solar telescope  

NASA Astrophysics Data System (ADS)

Integral Field Spectroscopy is an innovative technique that is being implemented in the state-of-the-art instruments of the largest night-time telescopes, however, it is still a novelty for solar instrumentation. A new concept of image slicer, called MuSICa (Multi-Slit Image slicer based on collimator-Camera), has been designed for the integral field spectrograph of the 4-m European Solar Telescope. This communication presents an image slicer prototype of MuSICa for GRIS, the spectrograph of the 1.5-m GREGOR solar telescope located at the Observatory of El Teide. MuSICa at GRIS reorganizes a 2-D field of view of 24.5 arcsec into a slit of 0.367 arcsec width by 66.76 arcsec length distributed horizontally. It will operate together with the TIP-II polarimeter to offer high resolution integral field spectropolarimetry. It will also have a bidimensional field of view scanning system to cover a field of view up to 1 by 1 arcmin.

Calcines, A.; López, R. L.; Collados, M.; Vega Reyes, N.

2014-07-01

250

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

NASA Technical Reports Server (NTRS)

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.

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

251

Detecting Life-bearing Extra-solar Planets with Space Telescopes  

E-print Network

One of the promising methods to search for life on extra-solar planets (exoplanets) is to detect life's signatures in their atmospheres. Spectra of exoplanet atmospheres at the modest resolution needed to search for oxygen, carbon dioxide, water, and methane will demand large collecting areas and large diameters to capture and isolate the light from planets in the habitable zones around the stars. For telescopes using coronagraphs to isolate the light from the planet, each doubling of telescope diameter will increase the available sample of stars by an order of magnitude, indicating a high scientific return if the technical difficulties of constructing very large space telescopes can be overcome. For telescopes detecting atmospheric signatures of transiting planets, the sample size increases only linearly with diameter, and the available samples are probably too small to guarantee detection of life-bearing planets. Using samples of nearby stars suitable for exoplanet searches, this paper shows that the demands of searching for life with either technique will require large telescopes, with diameters of order 10m or larger in space.

Steven V. W. Beckwith

2007-10-07

252

The pier and building of the European Solar Telescope (EST) F.C.M. Bettonvil*a  

E-print Network

-Hertogenbosch, The Netherlands; e Instituto de Astrofísica de Canarias, Avda Vía Láctea S/N, La Laguna 38205, Tenerife, Spain, local seeing, turbulence, kinetic energy. 1. INTRODUCTION The EST (European Solar Telescope)1 is a 4-m Palma or Tenerife. The basic function of the pier is to connect the telescope/enclosure with the ground

Rutten, Rob

253

Preliminary design of the visible spectro-polarimeter for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Visible Spectro-Polarimeter (ViSP) is one of the first light instruments for the Advanced Technology Solar Telescope (ATST). It is an echelle spectrograph designed to measure three different regions of the solar spectrum in three separate focal planes simultaneously between 380 and 900 nm. It will use the polarimetric capabilities of the ATST to measure the full Stokes parameters across the line profiles. By measuring the polarization in magnetically sensitive spectral lines the magnetic field vector as a function of height in the solar atmosphere can be obtained, along with the associated variation of the thermodynamic properties. The ViSP will have a spatial resolution of 0.04 arcsec over a 2 arcmin field of view (at 600 nm). The minimum spectral resolving power for all the focal planes is 180,000. The spectrograph supports up to 4 diffraction gratings and is fully automated to allow for rapid reconfiguration.

de Wijn, Alfred G.; Casini, Roberto; Nelson, Peter G.; Huang, Pei

2012-09-01

254

The Visible Spectro-Polarimeter (ViSP) for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Visible Spectro-Polarimeter (ViSP) is one of the first light instruments for the Advanced Technology Solar Telescope (ATST). It is an echelle spectrograph designed to measure three different regions of the solar spectrum in three separate focal planes simultaneously between 380 and 1600nm. It will use the polarimetric capabilities of the ATST to measure the full Stokes parameters across the line profiles. By measuring the polarization in magnetically sensitive spectral lines the magnetic field vector as a function of height in the solar atmosphere, along with the associated variation of the thermodynamic properties can be obtained. The ViSP will have a spatial resolution of 0.04 arc seconds over a 2 minute field of view (at 600nm). The minimum resolving power for all the focal planes is 180,000. The spectrograph supports up to 5 diffraction gratings and is fully automated to allow for rapid reconfiguration.

Nelson, Peter G.; Casini, Roberto; de Wijn, Alfred G.; Knoelker, Michael

2010-07-01

255

The Solar Neutron Telescope at Sierra Negra, Mexico, and the 7 september 2005 Event  

NASA Astrophysics Data System (ADS)

The Solar Neutron Telescope (SNT) at Sierra Negra (19.0 N, 97.3 W and 4580 m.a.s.l) is part of the world wide Solar Neutron Telescope Network. This SNT is composed by four 1m1m30 cm plastic scintillators (Sci). The telescope is completely surrounded by anti-coincidence propor-tional counters (PRCs). It is capable of registering four different energy deposition channels: Eż30, ż60, ż90 and ż120 MeV. The arrival direction of neutrons is determined by four layers of PRCs, orthogonally located underneath the SNT. We present the numerically simulated de-tector response to neutrons, protons, electrons and gammas entering the SNT with a range of energies from 100 to 1000 MeV. We report on the detector efficiency and on its angular reso-lution for particles impinging the device with different zenith angles. The simulation code was written using the Geant4 package, taking into account all relevant physical processes. Strong signals of energetic neutrons associated with the solar flare of 7 September 2005 were detected by the SNTs located at Mt. Chacaltaya, Bolivia and Sierra Negra, Mexico, Neutron Monitors (NMs) located at Mt. Chacaltaya and Mexico City. Based on the numerical simulations done to estimate the response of the detector, we did an analysis of the SNT data to obtain the energy spectrum of the solar neutrons. The SNT channels of different response functions in energy enabled us to obtain spectrum without any assumption on the emission time profile. The result supports conclusions of previous studies supporting the emission of the neutrons and gamma-rays starting at the same time and neutrons gradually and not impulsively emitted.

Francisco Valdes-Galicia, Jose; Gonzalez, Luis Xavier; Sanchez, Federico; Matsubara, Yutaka; Sako, Takeshi; Muraki, Yasushi; Watanabe, Kyoko

256

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

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

257

Real time controller for 37-element low-order solar adaptive optics system at 1m new vacuum solar telescope  

NASA Astrophysics Data System (ADS)

A low-order solar adaptive optics (AO) system had been successfully built and installed at 1m New Vacuum Solar Telescope (NVST) of Full-shine Lake Solar Observatory. The real time controller (RTC) of the AO system, which consists of a correlation tracker and a high-order wavefront correction controller, was developed. In this system, the absolute difference algorithm is used to detect wavefront gradients. A new architecture with field-programmable gate array (FPGA) and digital signal processor (DSP) for the real-time controller based on systolic array and pipeline was designed. The controller was integrated into the AO system and saw the first light on February 24th, 2011, using solar granulation as the beacon. Later, the AO-corrected high resolution sunspots images were obtained using sunspots as the beacon. The observational results show that the contrast and resolution of the solar images are improved evidently after the correction by the AO system. The design of the RTC and the observational results will be presented.

Zhu, Lei; Gu, Naiting; Chen, Shanqiu; Zhang, Lanqiang; Wang, Xiaoyun; Rao, Xuejun; Li, Mei; Rao, Changhui

258

The wavefront correction control system for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The ATST Wavefront Correction Control System (WCCS) is the high-level control software for the Wavefront Correction (WFC) system to be employed in the new Advanced Technology Solar Telescope. The WFC is comprised of a set of subsystems: the high-order adaptive optics system for correction of wavefront aberrations, an active optics system that calculates corrections for low-order distortions caused by optical misalignments, a context viewing camera to provide quick-look quality analysis data, and a limb guider for positioning an occulting mask on the solar disk. The operation and configuration of the WFC is determined by the operational modes set by the operator. The Telescope Control System (TCS) sends these operational modes to the WCCS, which is the interface between the telescope and the WFC. The WCCS adopts a modular approach to the organization of the software. At the top-level there is a high-level management controller which is the interface to the TCS. This management controller is responsible for the validation of commands received from the TCS and for the coordination and synchronization of the operation of the WFC subsystems. Separate subsystem controllers manage the functional behavior of each WFC subsystem. In this way the WCCS provides a consistent interface to the TCS for each subsystem while synchronizing and coordinating the components of the Wavefront Correction system.

Kinney, Ellyne K.; Richards, Kit; Johnson, Luke; Rimmele, Thomas R.; Barden, Samuel C.

2012-07-01

259

Reflectivity, polarization properties, and durability of metallic mirror coatings for the European Solar Telescope  

NASA Astrophysics Data System (ADS)

In the context of the conceptual design study for the European Solar Telescope (EST) we have investigated different metallic mirror coatings in terms of reflectivity, polarization properties and durability. Samples of the following coating types have been studied: bare aluminum, silver with different dielectric layers for protection and UV enhancement, and an aluminum-silver combination. From 2009 to 2011 we have carried out a long-term durability test under realistic observing conditions at the VTT solar telescope of the Observatorio del Teide (Tenerife, Spain), accompanied by repeated reflectivity measurements in the EST spectral working range (0.3 - 20 ?m), and by polarization measurements in the visible range. The test results allow us to find the optimum coatings for the different mirrors in the EST beampath and to eventually assess aging effects and re-coating cycles. The results of the polarization measurements are a valuable input for an EST telescope polarization model, helping to meet the stringent requirements on polarimetric accuracy.

Feller, A.; Krishnappa, N.; Pleier, O.; Hirzberger, J.; Jobst, P. J.; Schürmann, M.

2012-09-01

260

Solar System Research with the Spacewatch 1.8-m Telescope  

NASA Technical Reports Server (NTRS)

During this grant period, the 1.8-m Spacewatch telescope was put into routine operation to search for asteroids and comets ranging in location from near-Earth space to regions beyond the orbit of Neptune. All of these classes of objects can be detected simultaneously with our uniform scanning procedures. We are studying near Earth objects (NEOs), main belt asteroids, comets, Centaurs, and trans-Neptunian objects (TNOs), as well as the interrelationships of these classes and their bearing on the origin and evolution of the solar system. The Spacewatch 1.8-meter telescope is sensitive to V(mag) < 22.6 in sidereal scanning mode and is able to reach even fainter in longer 'staring' exposures, with a field of view 0.5 degrees square. These faint limits make the operation of the Spacewatch 1.8-m telescope complementary to asteroid surveys being done by other groups. Specifically, EAs smaller than 100 m in diameter and small main belt asteroids can be found, as well as more distant objects such as Centaurs/Scattered Disk Objects (SDOs) and TNOs. The 1.8-m telescope is also being used to do recoveries and astrometry of recently-discovered asteroids that subsequently become too faint for the other groups before good orbits are established.

McMillan, Robert S.

2001-01-01

261

On the use of Cherenkov Telescopes for outer Solar system body occultations  

NASA Astrophysics Data System (ADS)

Imaging Atmospheric Cherenkov Telescopes (IACTs) are arrays of very large optical telescopes that are well-suited for rapid photometry of bright sources. I investigate their potential in observing stellar occultations by small objects in the outer Solar system, Transjovian Objects (TJOs). These occultations cast diffraction patterns on the Earth. Current IACT arrays are capable of detecting objects smaller than 100 m in radius in the Kuiper Belt and 1 km radius out to 5000 au. The future Cherenkov Telescope Array (CTA) will have even greater capabilities. Because the arrays include several telescopes, they can potentially measure the speeds of TJOs without degeneracies, and the sizes of the TJOs and background stars. I estimate the achievable precision using a Fisher matrix analysis. With CTA, the precisions of these parameter estimations will be as good as a few per cent. I consider how often detectable occultations occur by members of different TJO populations, including Centaurs, Kuiper Belt Objects (KBOs), Oort Cloud objects, and satellites and Trojans of Uranus and Neptune. The great sensitivity of IACT arrays means that they likely detect KBO occultations once every O(10) hours when looking near the ecliptic. IACTs can also set useful limits on many other TJO populations.

Lacki, Brian C.

2014-12-01

262

Rocket studies of solar corona and transition region. [X-Ray spectrometer/spectrograph telescope  

NASA Technical Reports Server (NTRS)

The XSST (X-Ray Spectrometer/Spectrograph Telescope) rocket payload launched by a Nike Boosted Black Brant was designed to provide high spectral resolution coronal soft X-ray line information on a spectrographic plate, as well as time resolved photo-electric records of pre-selected lines and spectral regions. This spectral data is obtained from a 1 x 10 arc second solar region defined by the paraboloidal telescope of the XSST. The transition region camera provided full disc images in selected spectral intervals originating in lower temperature zones than the emitting regions accessible to the XSST. A H-alpha camera system allowed referencing the measurements to the chromospheric temperatures and altitudes. Payload flight and recovery information is provided along with X-ray photoelectric and UV flight data, transition camera results and a summary of the anomalies encountered. Instrument mechanical stability and spectrometer pointing direction are also examined.

Acton, L. W.; Bruner, E. C., Jr.; Brown, W. A.; Nobles, R. A.

1979-01-01

263

System safety and hazard analysis for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) is a four-meter class instrument being built to perform diffractionlimited observations of the sun. This paper describes how ATST has dealt with system safety and in particular hazard analysis during the design and development (D&D) phase. For ATST the development of a system safety plan and the oversight of the hazard analysis fell, appropriately, to systems engineering. We have adopted the methodology described in MIL-STD-882E, "Standard Practice for System Safety." While these methods were developed for use by the U.S. Department of Defense, they are readily applicable to the safety needs of telescope projects. We describe the details of our process, how it was implemented by the ATST design team, and some useful lessons learned. We conclude with a discussion of our safety related plans during the construction phase of ATST and beyond.

Hubbard, Robert P.

2010-07-01

264

Isoplanatic patch considerations for solar telescope multi-conjugate adaptive optics  

NASA Astrophysics Data System (ADS)

I compare recent site surveys for the future large 4-meter solar and 30-meter nighttime telescopes at the nearby Haleakala and Mauna Kea sites respectively. They show that the outstanding early morning image quality at the solar site corresponds indeed to that observed at the late night one at the nighttime site. That confirms the notion that daytime solar site heating only shows itself later in the morning. The nighttime survey includes observations of the refractive index structure function Cn 2(h) to high altitudes from which the radius of the isoplanatic patch (?0) can be determined. At zenith (? = 00) it equals 2.5 arcsec at 500 nm wavelength. For the early morning (best) seeing at the solar site, which occurs at ?sun = 750 and the cos1.6(?) dependence of ?0,that means an extremely small ?0 (0.26 arcsec). Such small values compromise Adaptive Optics (AO) solar correlation wavefront sensing for which areas are needed equal to about 8"× 8" I suggest options for measuring Cn2(h), and therefore ?0, during the day. These make use of the solar image as well as of daytime images of bright stars and planets. Some use the MASS technique on stars; some use the SHABAR technique using very large detector baselines on the Sun and shorter baselines on planets. It is suggested that these Cn2(h) measurements are made also during regular solar observations. In that way optimal solar observations can be planned using real-time ?0 observations by image selection and optimization of the MCAO configuration.

Beckers, Jacques M.

2014-08-01

265

NEXT GENERATION SPACE TELESCOPE  

E-print Network

the Early Universe: The Dark Ages . . . . . . . . . . . . .1 2 Seeing Beyond the Hubble Space Telescope the feasibility of a large aperture space telescope to follow the Hubble Space Telescope. The scientific goalsTHE NEXT GENERATION SPACE TELESCOPE Visiting a Time When Galaxies Were Young The NGST Study Team

Sirianni, Marco

266

Advanced Technology Solar Telescope M1 thermal control system design, modeling, and prototype testing  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) project plans to implement thermal control of the primary mirror using jet impingement of temperature controlled air on the backside of the meniscus mirror. This technique will be used to minimize temperature rise of the optical surface due to coating absorption, minimizing mirror seeing effects. The performance of this system has been evaluated using numerical modeling techniques and weather data recorded at the proposed observatory site. To aid in the design of the M1 thermal control system for the ATST, a prototype test bed was designed, fabricated and tested. This paper reviews the progress and results of this development program.

Hansen, Eric; Bulau, Scott; Phelps, LeEllen

2008-07-01

267

A simulation of the pointing performance of the Solar Optical Telescope  

NASA Technical Reports Server (NTRS)

The Space Shuttle-based Solar Optical Telescope (SOT) will be able to resolve details subtending 0.1 arcsec for continuous viewing over several hours. The SOT's jitter must contribute only 0.03 arcsec rms pointing error over the observation periods; this requirement is addressed with several control system layers encompassing the Shuttle, the Instrument Pointing System, the Prime Focus Image Control Functional System, and the Gregorian Focus Image Control Functional System. The mathematical models for system pointing stability presented give attention to the interaction of the structural and control systems on pointing stability and to Space Shuttle disturbances.

Bundas, David J.

1987-01-01

268

DYNAMICALLY EXCITED OUTER SOLAR SYSTEM OBJECTS IN THE HUBBLE SPACE TELESCOPE ARCHIVE  

SciTech Connect

We present the faintest mid-ecliptic latitude survey in the second part of Hubble Space Telescope archival search for outer solar system bodies. We report the discovery of 28 new trans-Neptunian objects and one small centaur (R {approx} 2 km) in the band 5 Degree-Sign -20 Degree-Sign off the ecliptic. The inclination distribution of these excited objects is consistent with the distribution derived from brighter ecliptic surveys. We suggest that the size and inclination distribution should be estimated consistently using suitable surveys with calibrated search algorithms and reliable orbital information.

Fuentes, Cesar I.; Trilling, David E. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Holman, Matthew J., E-mail: cesar.i.fuentes@nau.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-12-01

269

Conceptual design of the control software for the European Solar Telescope  

NASA Astrophysics Data System (ADS)

Aim of this paper is to present an overview of the conceptual design of the Control Software for the European Solar Telescope (EST), as emerged after the successful Conceptual Design Review held in June 2011 which formally concluded the EST Preliminary Design Study. After a general description of ECS (EST Control Software) architecture end-to-end, from operation concepts and observation preparations to the control of the planned focal plane instruments, the paper focuses on the arrangement devised to date of ECS to cope with the foreseen scientific requirements. EST major subsystems together with the functions to be controlled are eventually detailed and discussed.

Di Marcantonio, P.; Cirami, R.; Romano, P.; Cosentino, R.; Ermolli, I.; Giorgi, F.

2012-09-01

270

Will the Large Synoptic Survey Telescope Detect ExtraSolar Planetesimals Entering the Solar System?  

Microsoft Academic Search

Planetesimal formation is a common by-product of the star formation process. Taking the dynamical history of the solar system as a guideline---in which the planetesimal belts were heavily depleted due to gravitational perturbation with the giant planets---and assuming similar processes have taken place in other planetary systems, one would expect the interstellar space to be filled with extra-solar planetesimals. However,

Amaya Moro-Martín; Edwin L. Turner; Abraham Loeb

2009-01-01

271

The Kilodegree Extremely Little Telescope (KELT): A Small Robotic Telescope for Large-Area Synoptic Surveys  

E-print Network

The Kilodegree Extremely Little Telescope (KELT) project is a survey for planetary transits of bright stars. It consists of a small-aperture, wide-field automated telescope located at Winer Observatory near Sonoita, Arizona. The telescope surveys a set of 26 x 26 degree fields, together covering about 25% of the Northern sky, targeting stars in the range of 8solar-type main sequence stars.

Joshua Pepper; Richard W. Pogge; D. L. DePoy; J. L. Marshall; K. Z. Stanek; Amelia M. Stutz; Shawn Poindexter; Robert Siverd; Thomas P. O'Brien; Mark Trueblood; Patricia Trueblood

2007-07-30

272

Analysis of optical efficiency of METIS coronagraph telescope on board of the Solar Orbiter mission  

NASA Astrophysics Data System (ADS)

The Multi Element Telescope for Imaging and Spectroscopy (METIS) coronagraph is an instrument belonging to the SOLar Orbiter(SOLO) mission payload which will perform the imaging of the solar corona in three different spectral ranges: 30.4 nm (He-II Lyman-? line), 121.6 nm (H-I Lyman- ? line) and visible spectral range (500-650 nm). Optical coatings with high reflectance performances at the interested wavelengths are required to collect enough light at the detector level. Different multilayer structures based on Si/Mo couples with appropriate capping layers have been already designed and tested to achieve this purpose. A model has been developed in order to estimate the efficiency's performances of the instrument on the whole field of view (FoV) by considering the ray paths. The results shown have been obtained taking into account of the experimental results on multilayers structures previously tested and the optical design of the instrument.

Polito, V.; Corso, A. J.; Zuppella, P.; Nicolosi, P.; Fineschi, S.; Antonucci, E.; Windt, D. L.; Pelizzo, M. G.

2012-09-01

273

Feasibility study of a layer-oriented wavefront sensor for solar telescopes.  

PubMed

Solar multiconjugate adaptive optics systems rely on several wavefront sensors, which measure the incoming turbulent phase along several field directions to produce a tomographic reconstruction of the turbulent phase. In this paper, we explore an alternative wavefront sensing approach that attempts to directly measure the turbulent phase present at a particular height in the atmosphere: a layer-oriented cross-correlating Shack-Hartmann wavefront sensor (SHWFS). In an experiment at the Dunn Solar Telescope, we built a prototype layer-oriented cross-correlating SHWFS system conjugated to two separate atmospheric heights. We present the data obtained in the observations and complement these with ray-tracing computations to achieve a better understanding of the instrument's performance and limitations. The results obtained in this study strongly indicate that a layer-oriented cross-correlating SHWFS is not a practical design to measure the wavefront at a high layer in the atmosphere. PMID:24514185

Marino, Jose; Wöger, Friedrich

2014-02-01

274

NEW SOLAR TELESCOPE OBSERVATIONS OF MAGNETIC RECONNECTION OCCURRING IN THE CHROMOSPHERE OF THE QUIET SUN  

SciTech Connect

Magnetic reconnection is a process in which field-line connectivity changes in a magnetized plasma. On the solar surface, it often occurs with the cancellation of two magnetic fragments of opposite polarity. Using the 1.6 m New Solar Telescope, we observed the morphology and dynamics of plasma visible in the H{alpha} line, which is associated with a canceling magnetic feature (CMF) in the quiet Sun. The region can be divided into four magnetic domains: two pre-reconnection and two post-reconnection. In one post-reconnection domain, a small cloud erupted, with a plane-of-sky speed of 10 km s{sup -1}, while in the other one, brightening began at points and then tiny bright loops appeared and subsequently shrank. These features support the notion that magnetic reconnection taking place in the chromosphere is responsible for CMFs.

Chae, Jongchul; Ahn, K. [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Goode, P. R.; Yurchysyn, V.; Abramenko, V.; Andic, A.; Cao, W. [Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States); Park, Y. D. [Korea Astronomy and Space Science Institute, 838 Daedeokdaero, Daejeon 305-348 (Korea, Republic of)

2010-04-10

275

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

276

The soft x-ray photon-counting telescope for solar observations  

NASA Astrophysics Data System (ADS)

We present overview and development activities of a soft X-ray photon-counting spectroscopic imager for the solar corona that we conceive as a possible scientific payload for future space solar missions including Japanese Solar-C. The soft X-ray imager will employ a Wolter I grazing-incidence sector mirror with which images of the corona (1 MK to beyond 10 MK) will be taken with the highest-ever angular resolution (0.5"/pixel for a focal length of 4 m) as a solar Xray telescope. In addition to high-resolution imagery, we attempt to implement photon-counting capability for the imager by employing a backside-illuminated CMOS image sensor as the focal-plane device. Imaging-spectroscopy of the X-ray corona will be performed for the first time in the energy range from ~0.5 keV up to 10 keV. The imaging-spectroscopic observations with the soft X-ray imager will provide a noble probe for investigating mechanism(s) of magnetic reconnection and generation of supra-thermal (non-thermal) electrons associated with flares. Ongoing development activities in Japan towards the photon-counting imager is described with emphasis on that for sub-arcsecond-resolution grazing-incidence mirrors.

Sakao, Taro; Narukage, Noriyuki; Suematsu, Yoshinori; Watanabe, Kyoko; Shimojo, Masumi; Imada, Shinsuke; Ishikawa, Shin-nosuke; DeLuca, Edward E.

2014-07-01

277

Tilt extraction of scanning Fabry-Pérot interferometer for solar telescope  

NASA Astrophysics Data System (ADS)

Tunable Fabry-Pérot (F-P) based narrow band filter has been widely used in large solar telescope, which is utilized to isolate an arbitrary wavelength that we are interested in by adjusting the cavity length. However, it is difficult to guarantee that the mirror scan strictly parallel. As a result, the observations of the solar telescope would be affected. Here, we proposed a method to extract the tilt information of the scanning mirror. At first, the interferogram is obtained on the outer surface of the F-P interferometer. Then an interferogram of double-path is obtained from the multi-beam fringe pattern, which contains the tilt information of the moving mirror. Finally, the Radon transform is used in processing the interferogram to extract the tilted plane. Good results come out of the simulation of this method. It has high accuracy and high stability. It can provide feedback information to the closed-loop control system, and guide the tilt correction.

Liu, Chengmiao; Li, Jianxin; Sun, Yusheng; Zhu, Rihong

2014-11-01

278

Search for sub-eV mass solar axions by the CERN Axion Solar Telescope with 3He buffer gas.  

PubMed

The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV?m(a)?0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(a?)?2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)?1.15 eV, comfortably overlapping with cosmological hot dark matter bounds. PMID:22243149

Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Ezer, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Gazis, E N; Geralis, T; Giomataris, I; Gninenko, S; Gómez, H; Gruber, E; Guthörl, T; Hartmann, R; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakov?i?, K; Karuza, M; Königsmann, K; Kotthaus, R; Kr?mar, M; Kuster, M; Laki?, B; Laurent, J M; Liolios, A; Ljubi?i?, A; Lozza, V; Lutz, G; Luzón, G; Morales, J; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Rashba, T; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K

2011-12-23

279

Narrow-Band Imaging System for the Multi-application Solar Telescope at Udaipur Solar Observatory: Characterization of Lithium Niobate Etalons  

NASA Astrophysics Data System (ADS)

Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry-Perot etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt or temperature of the etalons. To characterize the etalons, a Littrow spectrograph was set up, in conjunction with a 15 cm Carl Zeiss Coud\\'e solar telescope. The etalons were calibrated for the solar spectral lines FeI 6173 {\\AA}, and CaII 8542 {\\AA}. In this work, we discuss the characterization of the Fabry-Perot etalons, specifically the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We also present solar images obtained using the system parameters. We also present solar images obtained using the system.

Raja Bayanna, A.; Mathew, Shibu K.; Venkatakrishnan, P.; Srivastava, N.

2014-10-01

280

The Large Binocular Telescope  

NASA Astrophysics Data System (ADS)

The Large Binocular Telescope (LBT) Observatory is a collaboration between institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio and Virginia. The telescope on Mt. Graham in southeastern Arizona uses two 8.4-meter diameter borosilicate honeycomb primary mirrors mounted side-by-side to produce a collecting area equivalent to an 11.8-meter circular aperture. A unique feature of LBT is that the light from the two primary mirrors can be combined to produce phased-array imaging of an extended field. This coherent imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65-meter telescope. The first on-sky phasing of the two telescopes in the mid-infrared occurred in October 2010 with the LBTI instrument in Fizeau mode. The telescope control system has been upgraded to allow binocular (2-sided) observations with pairs of instruments. The prime focus cameras (LBC) routinely operate in this mode. Improved collimation and pointing models have been deployed to keep both sides collimated and pointed at the same target. The control system has also been upgraded to allow observations of solar system objects at non-sidereal tracking rates. Science observations are scheduled for 60% of the nights including a significant fraction of adaptive optics imaging with the first adaptive secondary mirror and the FLAO system with natural guide stars. MODS1, a nearUV-optical spectrometer, has been added to the suite of science instruments along with LBC (visible imagers) and LUCI1 (near infrared spectrometer). LMIRcam (2-5 microns) and PISCES (1-2.5 microns) have been used for adaptive optics imaging. The remaining nights are scheduled for telescope and instrument commissioning activities as new instruments arrive. The second of the two F/15 adaptive secondary mirrors has been installed on the telescope in Fall 2011 and has been commissioned on-sky in Spring 2012.

Hill, J. M.; Green, R. F.; Ashby, D. S.; Brynnel, J. G.; Cushing, N. J.; Little, J. K.; Slagle, J. H.; Wagner, R. M.

2012-09-01

281

Progress making the top end optical assembly (TEOA) for the 4-meter Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

L-3 Integrated Optical Systems (IOS) Division has been selected by the National Solar Observatory (NSO) to design and produce the Top End Optical Assembly (TEOA) for the 4-meter Advanced Technology Solar Telescope (ATST) to operate at Haleakal', Maui. ATST will perform to a very high optical performance level in a difficult thermal environment. The TEOA, containing the 0.65-meter silicon carbide secondary mirror and support, mirror thermal management system, mirror positioning and fast tip-tilt system, field stop with thermally managed heat dump, thermally managed Lyot stop, safety interlock and control system, and support frame, operates in the "hot spot" at the prime focus of the ATST and so presents special challenges. In this paper, we describe progress in the L-3 technical approach to meeting these challenges, including silicon carbide off-axis mirror design, fabrication, and high accuracy figuring and polishing all within L-3; mirror support design; the design for stray light control; subsystems for opto-mechanical positioning and high accuracy absolute mirror orientation sensing; Lyot stop design; and thermal management of all design elements to remain close to ambient temperature despite the imposed solar irradiance load.

Canzian, Blaise; Barentine, J.; Arendt, J.; Bader, S.; Danyo, G.; Heller, C.

2012-09-01

282

Feasibility study of a layer-oriented wavefront sensor for solar telescopes: comment.  

PubMed

The future generation of telescopes will be equipped with multi-conjugate adaptive-optics (MCAO) systems in order to obtain high angular resolution over large fields of view. MCAO comes in two flavors: star- and layer-oriented. Existing solar MCAO systems rely exclusively on the star-oriented approach. Earlier we suggested a method to implement the layer-oriented approach, and in view of recent concerns by Marino and Wöger [Appl. Opt.53, 685 (2014)10.1364/AO.53.000685APOPAI1559-128X], we now explain the proposed scheme in further detail. We note that in any layer-oriented system one sensor is conjugated to the pupil and the others are conjugated to higher altitudes. For the latter, not all the sensing surface is illuminated by the entire field of view. The successful implementation of nighttime layer-oriented systems shows that the field reduction is no crucial limitation. In the solar approach the field reduction is directly noticeable because it causes vignetting of the Shack-Hartmann subaperture images. It can be accounted for by a suitable adjustment of the algorithms to calculate the local wavefront slopes. We discuss a further concern related to the optical layout of a layer-oriented solar system. PMID:25402984

Kellerer, Aglaé

2014-11-10

283

Simultaneous control of multiple instruments at the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) is a 4-meter solar observatory under construction at Haleakala, Hawaii. The simultaneous use of multiple instruments is one of the unique capabilities that makes the ATST a premier ground based solar observatory. Control of the instrument suite is accomplished by the Instrument Control System (ICS), a layer of software between the Observatory Control System (OCS) and the instruments. The ICS presents a single narrow interface to the OCS and provides a standard interface for the instruments to be controlled. It is built upon the ATST Common Services Framework (CSF), an infrastructure for the implementation of a distributed control system. The ICS responds to OCS commands and events, coordinating and distributing them to the various instruments while monitoring their progress and reporting the status back to the OCS. The ICS requires no specific knowledge about the instruments. All information about the instruments used in an experiment is passed by the OCS to the ICS, which extracts and forwards the parameters to the appropriate instrument controllers. The instruments participating in an experiment define the active instrument set. A subset of those instruments must complete their observing activities in order for the experiment to be considered complete and are referred to as the must-complete instrument set. In addition, instruments may participate in eavesdrop mode, outside of the control of the ICS. All instrument controllers use the same standard narrow interface, which allows new instruments to be added without having to modify the interface or any existing instrument controllers.

Johansson, Erik M.; Goodrich, Bret

2012-09-01

284

Multi Element Telescope for Imaging and Spectroscopy (METIS) coronagraph for the Solar Orbiter mission  

NASA Astrophysics Data System (ADS)

METIS, the “Multi Element Telescope for Imaging and Spectroscopy”, is a coronagraph selected by the European Space Agency to be part of the payload of the Solar Orbiter mission to be launched in 2017. The unique profile of this mission will allow 1) a close approach to the Sun (up to 0.28 A.U.) thus leading to a significant improvement in spatial resolution; 2) quasi co-rotation with the Sun, resulting in observations that nearly freeze for several days the large-scale outer corona in the plane of the sky and 3) unprecedented out-of-ecliptic view of the solar corona. This paper describes the experiment concept and the observational tools required to achieve the science drivers of METIS. METIS will be capable of obtaining for the first time: • simultaneous imaging of the full corona in polarized visible-light (590-650 nm) and narrow-band ultraviolet HI Lyman ? (121.6 nm); • monochromatic imaging of the full corona in the extreme ultraviolet He II Lyman ? (30.4 nm); • spectrographic observations of the HI and He II Ly ? in corona. These measurements will allow a complete characterization of the three most important plasma components of the corona and the solar wind, that is, electrons, hydrogen, and helium. This presentation gives an overview of the METIS imaging and spectroscopic observational capabilities to carry out such measurements.

Antonucci, Ester; Fineschi, Silvano; Naletto, Giampiero; Romoli, Marco; Spadaro, Daniele; Nicolini, Gianalfredo; Nicolosi, Piergiorgio; Abbo, Lucia; Andretta, Vincenzo; Bemporad, Alessandro; Auchčre, Frédéric; Berlicki, Arkadiusz; Bruno, Roberto; Capobianco, Gerardo; Ciaravella, Angela; Crescenzio, Giuseppe; Da Deppo, Vania; D'Amicis, Raffaella; Focardi, Mauro; Frassetto, Fabio; Heinzel, Peter; Lamy, Philippe L.; Landini, Federico; Massone, Giuseppe; Malvezzi, Marco A.; Moses, J. Dan; Pancrazzi, Maurizio; Pelizzo, Maria-Guglielmina; Poletto, Luca; Schühle, Udo H.; Solanki, Sami K.; Telloni, Daniele; Teriaca, Luca; Uslenghi, Michela

2012-09-01

285

Calibration of data from InfraRed Imaging Magnetograph for the New Solar Telescope  

NASA Astrophysics Data System (ADS)

The InfraRed Imaging Magnetograph (IRIM) takes advantage of the high spatial resolution of New Solar Telescope (NST). It adopts a rotating birefringent polymer to modulate polarization signals and two Wollaston prisms as analyzer. Dual beam setup is used to minimize the effect of image motion caused by seeing. Its field of view is 50" x 25" and the wavelengths of operation are Fe I 15648 A and He I 10830 A. Due to the off-axis shape of the NST primary and secondary mirrors, multiple calibration techniques should be combined to reconstruct the original Stokes parameters. Here, we would like to introduce current status of our calibration efforts and discuss how IRIM data can be used for scientific purposes.

Ahn, Kwangsu; Cao, W.; Gorceix, N.; Goode, P. R.

2012-05-01

286

A solar extreme ultraviolet telescope and spectrograph for space shuttle. Volume 1: Investigation and technical plan  

NASA Technical Reports Server (NTRS)

A scientific investigation of heating and mass transport in the solar corona that is currently planned for a future Shuttle/Spacelab flight is outlined. The instrument to be used is a near-normal incidence grating spectrograph fed by a grazing incidence Wolter Type 2 telescope. A toroidal grating design provides stigmatic images of the corona up to 8 arc min in extent over the spectral region from 225 A to 370 A. Spatial resolution of at least 2 arc sec and spectral resolution of 0.050 A is achievable throughout the central 4 arc min field or view. Primary scientific data are recorded on Schumann-type film. An H-alpha slit jaw monitor and zero order extreme ultraviolet monitor are also planned to support instrument operation.

Neupert, W. M.

1978-01-01

287

Solar Effects on Tensile and Optical Properties of Hubble Space Telescope Silver-Teflon(Registered Trademark) Insulation  

NASA Technical Reports Server (NTRS)

A section of the retrieved Hubble Space Telescope (HST) solar array drive arm (SADA) multilayer insulation (MLI), which experienced 8.25 years of space exposure, was analyzed for environmental durability of the top layer of silver-Teflon (DuPont) fluorinated ethylene propylene (Ag-FEP). Because the SADA MLI had solar and anti-solar facing surfaces and was exposed to the space environment for a long duration, it provided a unique opportunity to study solar effects on the environmental degradation of Ag-FEP, a commonly used spacecraft thermal control material. Data obtained included tensile properties, solar absorptance, surface morphology and chemistry. The solar facing surface was found to be extremely embrittled and contained numerous through-thickness cracks. Tensile testing indicated that the solar facing surface lost 60% of its mechanical strength and 90% of its elasticity while the anti-solar facing surface had ductility similar to pristine FEP. The solar absorptance of both the solar facing surface (0.155 plus or minus 0.032) and the anti-solar facing surface (0.208 plus or minus 0.012) were found to be greater than pristine Ag-FEP (0.074). Solar facing and anti-solar facing surfaces were microscopically textured, and locations of isolated contamination were present on the anti-solar surface resulting in increased localized texturing. Yet, the overall texture was significantly more pronounced on the solar facing surface indicating a synergistic effect of combined solar exposure and increased heating with atomic oxygen erosion. The results indicate a very strong dependence of degradation, particularly embrittlement, upon solar exposure with orbital thermal cycling having a significant effect.

deGroh, Kim, K.; Dever, Joyce A.; Snyder, Aaron; Kaminski, Sharon; McCarthy, Catherine E.; Rapoport, Alison L.; Rucker, Rochelle N.

2006-01-01

288

Software control of the Advanced Technology Solar Telescope enclosure PLC hardware using COTS software  

NASA Astrophysics Data System (ADS)

As PLCs evolve from simple logic controllers into more capable Programmable Automation Controllers (PACs), observatories are increasingly using such devices to control complex mechanisms1, 2. This paper describes use of COTS software to control such hardware using the Advanced Technology Solar Telescope (ATST) Common Services Framework (CSF). We present the Enclosure Control System (ECS) under development in Spain and the UK. The paper details selection of the commercial PLC communication library PLCIO. Implemented in C and delivered with source code, the library separates the programmer from communication details through a simple API. Capable of communicating with many types of PLCs (including Allen-Bradley and Siemens) the API remains the same irrespective of PLC in use. The ECS is implemented in Java using the observatory's framework that provides common services for software components. We present a design following a connection-based approach where all components access the PLC through a single connection class. The link between Java and PLCIO C library is provided by a thin Java Native Interface (JNI) layer. Also presented is a software simulator of the PLC based upon the PLCIO Virtual PLC. This creates a simulator operating below the library's API and thus requires no change to ECS software. It also provides enhanced software testing capabilities prior to hardware becoming available. Results are presented in the form of communication timing test data, showing that the use of CSF, JNI and PLCIO provide a control system capable of controlling enclosure tracking mechanisms, that would be equally valid for telescope mount control.

Borrowman, Alastair J.; de Bilbao, Lander; Arińo, Javier; Murga, Gaizka; Goodrich, Bret; Hubbard, John R.; Greer, Alan; Mayer, Chris; Taylor, Philip

2012-09-01

289

Optical design of a near-infrared imaging spectropolarimeter for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

In designing the optics of an imaging multi-etalon spectropolarimeter as a post-focus instrument for the Advanced Technology Solar Telescope (ATST), many constraints must be considered. Among these are the large entrance pupil diameter of the telescope (4 m), the demanded large field of view (?90 arc sec), high spectral resolving power (?200,000), and limited field-dependent blue-shift of the instrumental profile [?3 full width at half maximum (FWHM)], which require Fabry-Perot interferometers of large diameter (?200 mm), lighted by highly collimated beams. This implies large optical elements and long optical paths. Moreover, to use interference pre-filters with a relatively small diameter (?70 mm) and placed between the interferometers to reduce the inter-reflections in axial-mount, a "pupil adapter" must be included with a further increase of the optical path length. Although a multi-etalon spectropolarimeter works in quasi-monochromatic light, the Fraunhofer lines of interest cover a wide range of wavelengths (850 to 1650 nm), which demands a good chromatic aberration control. A low instrumental polarization (?0.5%) is also required to allow a high polarimetric precision. Finally, some secondary optical paths are required to perform the initial instrumental setup and to secure the best instrumental performances. A diffraction-limited optical solution for ATST is described that fulfills all the above requirements in a relative small volume.

Greco, Vincenzo; Cavallini, Fabio

2013-06-01

290

Geant4 simulation of the solar neutron telescope at Sierra Negra, Mexico  

NASA Astrophysics Data System (ADS)

The solar neutron telescope (SNT) at Sierra Negra (19.0°N, 97.3°W and 4580 m.a.s.l) is part of a worldwide network of similar detectors (Valdés-Galicia et al., (2004) [1]). This SNT has an area of 4 m2; it is composed by four 1 m×1 m×30 cm plastic scintillators (Sci). The Telescope is completely surrounded by anti-coincidence proportional counters (PRCs) to separate charged particles from the neutron flux. In order to discard photon background it is shielded on its sides by 10 mm thick iron plates and on its top by 5 mm lead plates. It is capable of registering four different channels corresponding to four energy deposition thresholds: E>30, >60, >90 and >120 MeV. The arrival direction of neutrons is determined by gondolas of PRCs in electronic coincidence, four layers of these gondolas orthogonally located underneath the SNT, two in the NS direction and two in the EW direction. We present here simulations of the detector response to neutrons, protons, electrons and gammas in range of energies from 100 to 1000 MeV. We report on the detector efficiency and on its angular resolution for particles impinging the device with different zenith angles. The simulation code was written using the Geant4 package (Agostinelli et al., (2003) [2]), taking into account all relevant physical processes.

González, L. X.; Sánchez, F.; Valdés-Galicia, J. F.

2010-02-01

291

A study on support structure of the one-meter primary mirror of the Space Solar Telescope  

NASA Astrophysics Data System (ADS)

In this paper, a reasonable support system of the one-meter primary mirror which is one of important components of the Space Solar Telescope is presented. This system can satisfy the optical calibration on the ground and launching mechanical environment, and guarantee a high precision state during the normal observation on the orbit.

Liu, Mei; Hu, Qi-Qian

2004-06-01

292

FPGA-based real time processing of the plenoptic wavefront sensor for the european solar telescope (EST)  

Microsoft Academic Search

This paper describes the development of the plenoptic wave front sensor for an adaptive optics systems proposed for the future EST Solar telescope. The plenoptic sensor offers additional optical information compared to traditional sensors at the expense of a significant increase in the image processing. This paper will concentrate on the processing required to develop a viable plenoptic sensor, describing

Y. Martin; L. F. Rodriguez-Ramos; J. Garcia; J. M. Rodriguez-Ramos

2010-01-01

293

Co-Alignment System (CAS) study. Report on task 1-3. [Solar Extreme Ultraviolet Telescope and Spectrometer pointing system  

NASA Technical Reports Server (NTRS)

The design of a suitable coalignment system (CAS) for the Solar Extreme Ultraviolet Telescope and Spectrometer (SEUTS) is presented. The CAS provides offset adjustment capabilities to SEUTS which will be mounted on a single large pointing system with other devices. The suitability of existing designs is determined and modifications are suggested.

Anderson, N. T.

1980-01-01

294

Narrow-Band Imaging System for the Multi-application Solar Telescope at Udaipur Solar Observatory: Characterization of Lithium Niobate Etalons  

E-print Network

Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry-Perot etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt or temperature of the etalons. To characterize the etalons, a Littrow spectrograph was set up, in conjunction with a 15 cm Carl Zeiss Coud\\'e solar telescope. The etalons were calibrated for the solar spectral lines FeI 6173 {\\AA}, and CaII 8542 {\\AA}. In this work, we discuss the characterization of the Fabry-Perot etalons, specifically the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We al...

Bayanna, A Raja; Venkatakrishnan, P; Srivastava, N

2014-01-01

295

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)

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.

Alexander, D. W.

1992-01-01

296

First Results of Coordinated Observations from IRIS and New Solar Telescope  

NASA Astrophysics Data System (ADS)

Most of the chromospheric structuring and dynamics is controlled by the underlying photospheric processes, associated with turbulent magnetoconvection, ubiquitous magnetic flux emergence, small-scale eruptions and acoustic events. The 1.6 m New Solar Telescope (NST) of Big Bear Solar Observatory offers a substantial improvement in ground-based high-resolution capabilities, and provides important support for the IRIS mission. The primary goal of the coordinated IRIS-NST observations is to obtain complementary data for investigations of photosphere-chromosphere links and drivers of the chromospheric dynamics. The coordinated NST observations are performed using the second-generation adaptive optics system AO-308, and three instruments: Broadband Filter Imagers (G-band and TiO), Visible Imaging Spectrometer (H-alpha), and Near InfraRed Imaging Spectropolarimeter (NIRIS). NIRIS provides high-cadence data in Fe I 1565 nm doublet which is the most Zeeman sensitive probe of magnetic fields in the deep photosphere, and in the He I 1083 nm multiplet for diagnostics of the upper chromosphere. We present initial results of the coordinated observations, and discuss properties of small-scale ejections in fibril magnetic structures, obtained from analysis of IRIS and NST data.

Kosovichev, A. G.; Cao, W.; Goode, P. R.; Gorceix, N.; Kleint, L.; Plymate, C.; Varsik, J. R.; Shumko, S.; Yurchyshyn, V.

2013-12-01

297

New Digital H-alpha Observation by Solar Flare Telescope at BOAO  

NASA Astrophysics Data System (ADS)

Recently, we have set up a new digital CCD camera system, MicroMax YHS-1300 manufactured by Roper Scientific for H-alpha observation by Solar Flare Telescope at Bohyunsan Optical Astronomical Observatory. It has a 12 bit dynamic range, a pixel number of 1300x1030, a thermoelectric cooler, and an electric shutter. Its readout speed is about 3 frames per second and the dark current is about 0.05 e-/p/s at -10 C degree. We have made a system performance test by confirming the system linearity, system gain, and system noise that its specification requires. We have also developed a data acquisition software which connects a digital camera controller to a PC and acquires H-alpha images via Microsoft C++ 6.0 under Windows 98. Comparisons of high quality H-alpha images of AR 9169 and AR 9283 obtained from SOFT with the corresponding images from Learmonth Solar Observatory in Australia confirm that our H-alpha digital observational system is performed properly. Finally, we present a set of H-alpha images taken from a two ribbon flare occurred in AR 9283.

Lee, C.-W.; Moon, Y.-J.; Park, Y. D.; Jang, B.-H.; Kim, Kap-Sung

2001-06-01

298

PROPERTIES OF UMBRAL DOTS AS MEASURED FROM THE NEW SOLAR TELESCOPE DATA AND MHD SIMULATIONS  

SciTech Connect

We studied bright umbral dots (UDs) detected in a moderate size sunspot and compared their statistical properties to recent MHD models. The study is based on high-resolution data recorded by the New Solar Telescope at the Big Bear Solar Observatory and three-dimensional (3D) MHD simulations of sunspots. Observed UDs, living longer than 150 s, were detected and tracked in a 46 minute long data set, using an automatic detection code. A total of 1553 (620) UDs were detected in the photospheric (low chromospheric) data. Our main findings are (1) none of the analyzed UDs is precisely circular, (2) the diameter-intensity relationship only holds in bright umbral areas, and (3) UD velocities are inversely related to their lifetime. While nearly all photospheric UDs can be identified in the low chromospheric images, some small closely spaced UDs appear in the low chromosphere as a single cluster. Slow-moving and long-living UDs seem to exist in both the low chromosphere and photosphere, while fast-moving and short-living UDs are mainly detected in the photospheric images. Comparison to the 3D MHD simulations showed that both types of UDs display, on average, very similar statistical characteristics. However, (1) the average number of observed UDs per unit area is smaller than that of the model UDs, and (2) on average, the diameter of model UDs is slightly larger than that of observed ones.

Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.; Goode, P. R.; Cao, W. [Big Bear Solar Observatory, Big Bear City, CA 92314 (United States); Rempel, M. [High Altitude Observatory, NCAR, Boulder, CO 80307-3000 (United States); Kitai, R.; Watanabe, H. [Kwasan and Hida Observatories, Kyoto University, Kyoto 607-8417 (Japan)

2012-02-01

299

The LSST and Solar System Science  

Microsoft Academic Search

The Large-aperture Synoptic Survey Telescope (LSST) was a highly ranked Major Initiative in Astronomy and Astrophysics in the New Millenium, the last decadal survey. The LSST's potential for exploring the Solar System was a major reason for this high ranking. The proposed design (see poster by Angel, this meeting) provides an effective aperture of 6.9-m and a 7 square degree

K. H. Cook; J. A. Tyson; C. Stubbs; E. L. Bowell; A. W. Harris; R. Binzel; W. Craig

2001-01-01

300

The 2012 status of the MCAO testbed for the GREGOR solar telescope  

NASA Astrophysics Data System (ADS)

We look back on two years of experience with the laboratory MCAO testbed for the GREGOR solar telescope. GREGOR’s MCAO features four adaptive mirrors, i. e. one tip-tilt mirror, and three DMs to compensate for turbulence around 0 km, 5 km, and 15.5 km above ground. Two different Hartmann-Shack wavefront sensor units are used for wavefront tomography. A sensor with a narrow field of view and smaller subapertures is dedicated to high-order aberrations on the optical axis. This sensor directly follows the pupil plane DM and does not see the high-altitude DMs. The second sensor features larger subapertures and 19 guide regions spread over a wide field of view for off-axis wavefront sensing. We show that high-altitude DMs cause rapidly changing pupil distortions and thus misregistration, which renders the interaction of a pupil-plane DM and a subsequent wavefront sensor non-linear. We rewrote the control software for cleaner and more flexible code, and we switched to modal wavefront reconstruction from direct reconstruction. The original digital interfacing of the DMs high-voltage electronics didn’t prove to be reliable. Thus, we developed a new interface board that is based on CameraLink/ChannelLink technology to transmit the DM commands from the control computer. In this paper we present the innovations and some of the first experimental performance measurements with two DMs. One DM failed before scientific grade data was recorded with three DMs. This DM will be replaced soon. We conclude that GREGOR’s MCAO system is now ready for first on-sky tests at the telescope.

Schmidt, Dirk; Berkefeld, Thomas; Heidecke, Frank

2012-07-01

301

UPDATED ANALYSIS OF THE UPWIND INTERPLANETARY HYDROGEN VELOCITY AS OBSERVED BY THE HUBBLE SPACE TELESCOPE DURING SOLAR CYCLE 23  

SciTech Connect

The interplanetary hydrogen (IPH), a population of neutrals that fill the space between planets inside the heliosphere, carries the signature of the interstellar medium (ISM) and the heliospheric interface. As the incoming ISM-ionized component deflects at the heliopause, charge exchange reactions decelerate the bulk motion of the neutrals that penetrate the heliosphere. Inside the heliosphere, the IPH bulk velocity is further affected by solar gravity, radiation pressure, and ionization processes, with the latter two processes dependent on solar activity. Solar cycle 23 provided the first partial temporal map of the IPH velocity, including measurements from the Hubble Space Telescope (HST) spectrometers (Goddard High Resolution Spectrograph (GHRS) and Space Telescope Imaging Spectrograph (STIS)) and the Solar and Heliospheric Observatory/Solar Wind ANisotropies (SWAN) instrument. We present an updated analysis of IPH velocity measurements from GHRS and STIS and compare these results with those of SWAN and two different time-dependent models. Our reanalysis of STIS data reveals a significant change in IPH velocity relative to earlier reports, because of the contamination by geocoronal oxygen that was not accounted for. While current models of the heliospheric interface predict the observed IPH velocity for solar maximum, they are not consistent with data covering solar minimum. With updates to the HST data points, we now find that all data can be fit by the existing models to within 1{sigma}, with the exception of SWAN observations taken at solar minimum (1997/1998). We conclude that the current data lack the temporal coverage and/or precision necessary to determine the detailed characteristics of the solar cycle dependence. Hence, new observations are merited.

Vincent, Frederic E.; Ben-Jaffel, Lotfi [Institut d'Astrophysique de Paris, CNRS-UPMC, 75014 Paris (France); Harris, Walter M. [Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616 (United States)

2011-09-10

302

Dynamics in Sunspot Umbra as Seen in New Solar Telescope and Interface Region Imaging Spectrograph Data  

NASA Astrophysics Data System (ADS)

We analyze sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) slit-jaw and spectral data and narrow-band chromospheric images from the New Solar Telescope (NST) for the main sunspot in NOAA AR 11836. We report that the difference between the shock arrival times as measured by the Mg II k 2796.35 Ĺ and Si IV 1393.76 Ĺ line formation levels changes during the observed period, and peak-to-peak delays may range from 40 s to zero. The intensity of chromospheric shocks also displays long-term (about 20 min) variations. NST's high spatial resolution H? data allowed us to conclude that, in this sunspot, umbral flashes (UFs) appeared in the form of narrow bright lanes stretched along the light bridges and around clusters of umbral bright points. The time series also suggested that UFs preferred to appear on the sunspot-center side of light bridges, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. The sunspot's umbra as seen in the IRIS chromospheric and transition region data appears bright above the locations of light bridges and the areas where the dark umbra is dotted with clusters of umbral dots. Co-spatial and co-temporal data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory showed that the same locations were associated with bright footpoints of coronal loops suggesting that the light bridges may play an important role in heating the coronal sunspot loops. Finally, the power spectra analysis showed that the intensity of chromospheric and transition region oscillations significantly vary across the umbra and with height, suggesting that umbral non-uniformities and the structure of sunspot magnetic fields may play a role in wave propagation and heating of umbral loops.

Yurchyshyn, V.; Abramenko, V.; Kilcik, A.

2015-01-01

303

PRECURSOR OF SUNSPOT PENUMBRAL FORMATION DISCOVERED WITH HINODE SOLAR OPTICAL TELESCOPE OBSERVATIONS  

SciTech Connect

We present observations of a precursory signature that would be helpful for understanding the formation process of sunspot penumbrae. The Hinode Solar Optical Telescope successfully captured the entire evolution of a sunspot from the pore to a large well-developed sunspot with penumbra in an emerging flux region appearing in NOAA Active Region 11039. We found an annular zone (width 3''-5'') surrounding the umbra (pore) in Ca II H images before the penumbra formed around the umbra. The penumbra developed as if to fill the annular zone. The annular zone shows weak magnetogram signals, meaning less magnetic flux or highly inclined fields there. Pre-existing ambient magnetic field islands were distributed at the outer edge of the annular zone and did not come into the zone. There are no strong systematic flow patterns in the zone, but we occasionally observed small magnetic flux patches streaming out. The observations indicate that the annular zone is different from the sunspot moat flow region and that it represents the structure in the chromosphere. We conclude that the annular zone reflects the formation of a magnetic canopy overlying the region surrounding the umbra at the chromospheric level, long before the formation of the penumbra at the photospheric level. The magnetic field structure in the chromosphere needs to be considered in the formation process of the penumbrae.

Shimizu, Toshifumi [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan); Ichimoto, Kiyoshi [Kwasan and Hida Observatories, Kyoto University, Kamitakara-cho, Takayama, Gifu 506-1314 (Japan); Suematsu, Yoshinori, E-mail: shimizu.toshifumi@isas.jaxa.jp [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

2012-03-10

304

Opto-thermal analysis of a lightweighted mirror for solar telescope.  

PubMed

In this paper, an opto-thermal analysis of a moderately heated lightweighted solar telescope mirror is carried out using 3D finite element analysis (FEA). A physically realistic heat transfer model is developed to account for the radiative heating and energy exchange of the mirror with surroundings. The numerical simulations show the non-uniform temperature distribution and associated thermo-elastic distortions of the mirror blank clearly mimicking the underlying discrete geometry of the lightweighted substrate. The computed mechanical deformation data is analyzed with surface polynomials and the optical quality of the mirror is evaluated with the help of a ray-tracing software. The thermal print-through distortions are further shown to contribute to optical figure changes and mid-spatial frequency errors of the mirror surface. A comparative study presented for three commonly used substrate materials, namely, Zerodur, Pyrex and Silicon Carbide (SiC) is relevant to vast area of large optics requirements in ground and space applications. PMID:23546089

Banyal, Ravinder K; Ravindra, B; Chatterjee, S

2013-03-25

305

Plate coil thermal test bench for the Daniel K. Inouye Solar Telescope (DKIST) carousel cooling system  

NASA Astrophysics Data System (ADS)

Analyses have shown that even a white-painted enclosure requires active exterior skin-cooling systems to mitigate dome seeing which is driven by thermal nonuniformities that change the refractive index of the air. For the Daniel K. Inouye Solar Telescope (DKIST) Enclosure, this active surface temperature control will take the form of a system of water cooled plate coils integrated into the enclosure cladding system. The main objective of this system is to maintain the surface temperature of the enclosure as close as possible to, but always below, local ambient temperature in order to mitigate this effect. The results of analyses using a multi-layer cladding temperature model were applied to predict the behavior of the plate coil cladding system and ultimately, with safety margins incorporated into the resulting design thermal loads, the detailed designs. Construction drawings and specifications have been produced. Based on these designs and prior to procurement of the system components, a test system was constructed in order to measure actual system behavior. The data collected during seasonal test runs at the DKIST construction site on Haleakal? are used to validate and/or refine the design models and construction documents as appropriate. The test fixture was also used to compare competing hardware, software, components, control strategies, and configurations. This paper outlines the design, construction, test protocols, and results obtained of the plate coil thermal test bench for the DKIST carousel cooling system.

Phelps, LeEllen; Murga, Gaizka; Montijo, Guillermo; Hauth, David

2014-08-01

306

Fine pointing of the Solar Optical Telescope in the Space Shuttle environment  

NASA Technical Reports Server (NTRS)

Instruments requiring fine (i.e., sub-arcsecond) pointing, such as the Solar Optical Telescope (SOT), must be equipped with two-stage pointing devices, coarse and fine. Coarse pointing will be performed by a gimbal system, such as the Instrument Pointing System, while the image motion compensation (IMC) will provide fine pointing. This paper describes work performed on the SOT concept design that illustrates IMC as applied to SOT. The SOT control system was modeled in the frequency domain to evaluate performance, stability, and bandwidth requirements. The two requirements of the pointing control, i.e., the 2 arcsecond reproducibility and 0.03 arcsecond rms pointing jitter, can be satisfied by use of IMC at about 20 Hz bandwidth. The need for this high bandwidth is related to Shuttle-induced disturbances that arise primarily from man push-offs and vernier thruster firings. A block diagram of SOT model/stability analysis, schematic illustrations of the SOT pointing system, and a structural model summary are included.

Gowrinathan, S.

1985-01-01

307

Magnetic Reconnection between Small-scale Loops Observed with the New Vacuum Solar Telescope  

NASA Astrophysics Data System (ADS)

Using the high tempo-spatial resolution H? images observed with the New Vacuum Solar Telescope, we report solid observational evidence of magnetic reconnection between two sets of small-scale, anti-parallel loops with an X-shaped topology. The reconnection process contains two steps: a slow step with a duration of more than several tens of minutes, and a rapid step lasting for only about three minutes. During the slow reconnection, two sets of anti-parallel loops gradually reconnect, and new loops are formed and stacked together. During the rapid reconnection, the anti-parallel loops approach each other quickly, and then rapid reconnection takes place, resulting in the disappearance of the former loops. In the meantime, new loops are formed and separate. The region between the approaching loops is brightened, and the thickness and length of this region are determined to be about 420 km and 1.4 Mm, respectively. During the rapid reconnection process, obvious brightenings at the reconnection site and apparent material ejections outward along reconnected loops are observed. These observed signatures are consistent with predictions by reconnection models. We suggest that the successive slow reconnection changes the conditions around the reconnection site and triggers instabilities, thus leading to the rapid approach of the anti-parallel loops and resulting in the rapid reconnection.

Yang, Shuhong; Zhang, Jun; Xiang, Yongyuan

2015-01-01

308

Magnetic reconnection between small-scale loops observed with the New Vacuum Solar Telescope  

E-print Network

Using the high tempo-spatial resolution H$\\alpha$ images observed with the New Vacuum Solar Telescope, we report the solid observational evidence of magnetic reconnection between two sets of small-scale anti-parallel loops with an X-shaped topology. The reconnection process contains two steps: a slow step with the duration of more than several tens of minutes, and a rapid step lasting for only about three minutes. During the slow reconnection, two sets of anti-parallel loops reconnect gradually, and new loops are formed and stacked together. During the rapid reconnection, the anti-parallel loops approach each other quickly, and then the rapid reconnection takes place, resulting in the disappearance of former loops. In the meantime, new loops are formed and separate. The region between the approaching loops is brightened, and the thickness and length of this region are determined to be about 420 km and 1.4 Mm, respectively. During the rapid reconnection process, obvious brightenings at the reconnection site an...

Yang, Shuhong; Xiang, Yongyuan

2014-01-01

309

Site evaluation study for the Indian National Large Solar Telescope using microthermal measurements  

NASA Astrophysics Data System (ADS)

A microthermal seeing measurement device has been developed in-house to measure the temperature structure function DT(r, h) and the air temperature Tair(h). A pressure sensor, located adjacent to it, measures the average barometric pressure P(h). From the data measured, the temperature structure coefficient C_T^2(r, h) and the refractive index structure constant C_N^2(h) are computed for the five equidistant microthermal seeing layers in the 3-15 m range in the surface layers. A statistical analysis is performed on the local coherence length ro(loc)(h1, h2). Corresponding values of the atmospheric seeing ?(loc)(h1, h2) for all 10 microthermal seeing slabs is also computed and plotted, and the data are logged in real time. Because the characterization of the three sites is under way and the best site for the National Large Solar Telescope facility is yet to be determined, in this paper I discuss the preliminary results obtained from the Hanle site. A summary of the first results is as follows: ?(loc) (3 m, 6 m) = 0.663 arcsec, ?(loc) (6 m, 9 m) = 0.465 arcsec, ?(loc) (9 m, 12 m) = 0.363 arcsec and ?(loc) (12 m, 15 m) = 0.315 arcsec.

Dhananjay, K.

2014-01-01

310

Cryogenic detectors for infrared astronomy: the Single Aperture Far-InfraRed (SAFIR) Observatory  

Microsoft Academic Search

The development of a large, far-infrared telescope in space has taken on a new urgency with breakthroughs in detector technology and recognition of the fundamental importance of the far-infrared spectral region to questions ranging from cosmology to our own Solar system. The Single Aperture Far-InfraRed (SAFIR) Observatory is 10m-class far-infrared observatory that would begin development later in this decade to

Dominic J. Benford; S. Harvey Moseley

2004-01-01

311

Measurement of the point spread function and effective area of the Solar-A Soft X-ray Telescope mirror  

NASA Technical Reports Server (NTRS)

A grazing incidence solar X-ray telescope, Soft X-ray Telescope (SXT), will be flown on the Solar-A satellite in 1991. Measurements have been conducted to determine the focal length, Point Spread Function (PSF), and effective area of the SXT mirror. The measurements were made with pinholes, knife edges, a CCD, and a proportional counter. The results show the 1/r character of the PSF, and indicate a half power diameter of 4.9 arcsec and an effective area of 1.33 sq cm at 13.3 A (0.93 keV). The mirror was found to provide a high contrast image with very little X-ray scattering.

Lemen, J. R.; Claflin, E. S.; Brown, W. A.; Bruner, M. E.; Catura, R. C.

1989-01-01

312

Diffraction-limited constant-resolution zoom lens across multi-wavelengths for the Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

Zoom lenses are usually designed for a specified waveband and change magnification, and thus resolution, for different object sizes or different object distances. However, the Advanced Technology Solar Telescope (ATST)/ Visible Light Broadband Imager (VLBI), under development by the National Solar Observatory, require constant resolution for different wavelengths over a wide spectral range (388.3 nm 3o 854.2 nm). An eight-element zoom lens meeting this requirement is presented, and yields diffraction-limited performance over the field of view at nine specific wavelength/zoom positions. Each zoom position, corresponding to a specific wavelength, has a focal length and f/number for achieving constant CCD sampling. The Strehl ratio of the telescope is greater than 90% over all zoom positions.

An, Hyun Kyoung; Pitalo, Stephen K.

2007-01-01

313

Production of the 4.26 m ZERODUR mirror blank for the Advanced Technology Solar telescope (ATST)  

NASA Astrophysics Data System (ADS)

The Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST) will be the most powerful solar telescope in the world. It is currently being built by the Association of Universities for Research in Astronomy (AURA) in a height of 3000 m above sea level on the mountain Haleakala of Maui, Hawaii. The primary mirror blank of diameter 4.26 m is made of the extremely low thermal expansion glass ceramic ZERODUR® of SCHOTT AG Advanced Optics. The DKIST primary mirror design is extremely challenging. With a mirror thickness of only 78 to 85 mm it is the smallest thickness ever machined on a mirror of 4.26 m in diameter. Additionally the glassy ZERODUR® casting is one of the largest in size ever produced for a 4 m class ZERODUR® mirror blank. The off axis aspherical mirror surface required sophisticated grinding procedures to achieve the specified geometrical tolerance. The small thickness of about 80 mm required special measures during processing, lifting and transport. Additionally acid etch treatment was applied to the convex back-surface and the conical shaped outer diameter surface to improve the strength of the blank. This paper reports on the challenging tasks and the achievements on the material property and dimensional specification parameter during the production of the 4.26 m ZERODUR® primary mirror blank for AURA.

Jedamzik, Ralf; Werner, Thomas; Westerhoff, Thomas

2014-07-01

314

Analysis of telescope arrays for deep space optical communications  

Microsoft Academic Search

It has been very well established in the literature that the cost of a large aperture telescope grows exponentially as a function of its diameter. On Earth, large aperture telescopes in excess of 10m also have the disadvantage of undergoing gravitational and other environmental effects. Array configurations, instead, may be the potential alternatives when large aperture telescopes are considered for

Ali Asghar Eftekhar; S. Khjorasani; A. Adibi; F. Amoozegar; S. Piazzolla

2005-01-01

315

EUV and soft x-ray telescope-spectrometer for imaging spectroscopy on the Solar Orbiter mission: configurations with multilayer-coated optics  

Microsoft Academic Search

Two configurations with multilayer-coated optics for an EUV and soft X-ray telescope-spectrometer for imaging spectroscopy on the Solar Orbiter mission are presented. The telescope is designed with conventional grazing-incidence optics, in order to reduce the thermal load on optics looking directly at the solar disk. The spectrometer mounts a normal-incidence multilayer-coated grating, being protected by the entrance slit. Two configurations

Luca Poletto; Giuseppe Tondello; Massimo Landini

2001-01-01

316

High resolution telescope  

DOEpatents

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.

Massie, Norbert A. (San Ramon, CA); Oster, Yale (Danville, CA)

1992-01-01

317

Simulated Solar Flare X-Ray and Thermal Cycling Durability Evaluation of Hubble Space Telescope Thermal Control Candidate Replacement Materials  

NASA Technical Reports Server (NTRS)

During the Hubble Space Telescope (HST) second servicing mission (SM2), astronauts noticed that the multilayer insulation (MLI) covering the telescope was damaged. Large pieces of the outer layer of MLI (aluminized Teflon fluorinated ethylene propylene (Al-FEP)) were torn in several locations around the telescope. A piece of curled up Al-FEP was retrieved by the astronauts and was found to be severely embrittled, as witnessed by ground testing. Goddard Space Flight Center (GSFC) organized a HST MLI Failure Review Board (FRB) to determine the damage mechanism of FEP in the HST environment, and to recommend replacement insulation material to be installed on HST during the third servicing mission (SM3) in 1999. Candidate thermal control replacement materials were chosen by the FRB and tested for environmental durability under various exposures and durations. This paper describes durability testing of candidate materials which were exposed to charged particle radiation, simulated solar flare x-ray radiation and thermal cycling under load. Samples were evaluated for changes in solar absorptance and tear resistance. Descriptions of environmental exposures and durability evaluations of these materials are presented.

deGroh, Kim K.; Banks, Bruce A.; Sechkar, Edward A.; Scheiman, David A.

1998-01-01

318

A normal incidence, high resolution X-ray telescope for solar coronal observations  

NASA Technical Reports Server (NTRS)

A Normal Incidence high resolution X-ray Telescope is reported. The design of a telescope assembly which, after fabrication, will be integrated with the mirror fabrication process is described. The assembly is engineered to fit into the Black Brant rocket skin to survive sounding rocket launch conditions. A flight ready camera is modified and tested.

Golub, L.

1984-01-01

319

Development of the tip-tilt mirror system for the solar XUV telescope  

Microsoft Academic Search

This paper describes the design and prelaunch performance of the tip-tilt mirror (TTM) system developed for the XUV Cassegrain telescope aboard the ISAS sounding rocket experiment. The spatial resolution of the telescope is about 5 arcsec, whereas the rocket pointing is only controlled to be within +\\/- 0.5 degree around the target without stability control. The TTM is utilized to

Kazuhide Kodeki; Kazuhiko Fukushima; Toshio Kashiwase; Masao Inoue; Toshifumi Shimizu; Tsuyoshi Yoshida; Taro Sakao; Hirohisa Hara; Shin'ichi Nagata; Ryouhei Kano; Saku Tsuneta

1998-01-01

320

Search for Solar Axions by the CERN Axion Solar Telescope with He3 Buffer Gas: Closing the Hot Dark Matter Gap  

NASA Astrophysics Data System (ADS)

The CERN Axion Solar Telescope has finished its search for solar axions with He3 buffer gas, covering the search range 0.64 eV?ma?1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of ga??3.3×10-10 GeV-1 at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of ga?, for example by the currently discussed next generation helioscope International AXion Observatory.

Arik, M.; Aune, S.; Barth, K.; Belov, A.; Borghi, S.; Bräuninger, H.; Cantatore, G.; Carmona, J. M.; Cetin, S. A.; Collar, J. I.; Da Riva, E.; Dafni, T.; Davenport, M.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galán, J.; García, J. A.; Gardikiotis, A.; Garza, J. G.; Gazis, E. N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gómez, H.; Gómez Marzoa, M.; Gruber, E.; Guthörl, T.; Hartmann, R.; Hauf, S.; Haug, F.; Hasinoff, M. D.; Hoffmann, D. H. H.; Iguaz, F. J.; Irastorza, I. G.; Jacoby, J.; Jakov?i?, K.; Karuza, M.; Königsmann, K.; Kotthaus, R.; Kr?mar, M.; Kuster, M.; Laki?, B.; Lang, P. M.; Laurent, J. M.; Liolios, A.; Ljubi?i?, A.; Luzón, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M. J.; Raffelt, G.; Riege, H.; Rodríguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P. S.; Solanki, S. K.; Stewart, L.; Tomás, A.; Tsagri, M.; van Bibber, K.; Vafeiadis, T.; Villar, J.; Vogel, J. K.; Yildiz, S. C.; Zioutas, K.; CAST Collaboration

2014-03-01

321

Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.  

PubMed

The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ? ma ? 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of ga? ? 3.3 × 10(-10)? GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of ga?, for example by the currently discussed next generation helioscope International AXion Observatory. PMID:24655238

Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Da Riva, E; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Garza, J G; Gazis, E N; Geralis, T; Georgiopoulou, E; Giomataris, I; Gninenko, S; Gómez, H; Gómez Marzoa, M; Gruber, E; Guthörl, T; Hartmann, R; Hauf, S; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakov?i?, K; Karuza, M; Königsmann, K; Kotthaus, R; Kr?mar, M; Kuster, M; Laki?, B; Lang, P M; Laurent, J M; Liolios, A; Ljubi?i?, A; Luzón, G; Neff, S; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Shilon, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J; Vogel, J K; Yildiz, S C; Zioutas, K

2014-03-01

322

The High-Resolution Lightweight Telescope for the EUV (HiLiTE)  

SciTech Connect

The High-resolution Lightweight Telescope for the EUV (HiLiTE) is a Cassegrain telescope that will be made entirely of Silicon Carbide (SiC), optical substrates and metering structure alike. Using multilayer coatings, this instrument will be tuned to operate at the 465 {angstrom} Ne VII emission line, formed in solar transition region plasma at {approx}500,000 K. HiLiTE will have an aperture of 30 cm, angular resolution of {approx}0.2 arc seconds and operate at a cadence of {approx}5 seconds or less, having a mass that is about 1/4 that of one of the 20 cm aperture telescopes on the Atmospheric Imaging Assembly (AIA) instrument aboard NASA's Solar Dynamics Observatory (SDO). This new instrument technology thus serves as a path finder to a post-AIA, Explorer-class missions.

Martinez-Galarce, D S; Boerner, P; Soufli, R; De Pontieu, B; Katz, N; Title, A; Gullikson, E M; Robinson, J C; Baker, S L

2008-06-02

323

A Scanning Hartmann Focus Test for the EUVI Telescopes aboard STEREO  

NASA Technical Reports Server (NTRS)

The Solar TErrestrial RElations Observatory (STEREO), the third mission in NASA s Solar Terrestrial Probes program, was launched in 2006 on a two year mission to study solar phenomena like coronal mass ejections. STEREO consists of two nearly identical satellites, each carrying a suite of instruments that provide, among other data, simultaneous images of the Sun. One of these telescopes is the Extreme Ultraviolet Instrument (EUVI). There are two EUVI telescopes, one on each STEREO satellite (EUVI-A and EUVI-B). EUVI is a normal incidence, 98mm diameter, Ritchey-Chretien telescope designed to obtain wide field of view (approx.1deg) images of the Sun at short wavelengths (approx.20nm) using a CCD detector. The telescope entrance aperture is divided into four quadrants by a mask near the secondary mirror spider veins. A mechanism that rotates another mask allows only one of these sub-apertures to accept light from the Sun during an observation. The EUVI is thus four co-aligned, off-axis telescopes. Each off-axis segment on the primary and secondary mirrors has a different extreme ultraviolet coating stack. Furthermore, the aperture select mechanism is synchronized with a filter wheel mechanism near the CCD detector. The EUVI contains no focus mechanism. Models predict that the difference in on-orbit operating temperature and ambient clean room conditions yield a "best focus" difference between integration and operation of approx. 0.2mm.

Ohl, R.; Antonille, S.; Aronstein, D.; Dean, B.; Delmont, M.; Eichord, W.; Frey, B.; Kubalak, D.; Wilson, M.; Redman, K.; Hynes, S.; Shiri, R.; Smith, J. S.; Thompson, P.

2007-01-01

324

Development of Solar Scintillometer  

NASA Astrophysics Data System (ADS)

The index of scintillation measurement is a good parameter to compare different sites for image quality or `seeing'.We have developed a scintillometer, which is deployed on the high resolution SPAR telescope in the island site of Udaipur Solar Observatory, for the site characterization to specify the proposed MAST (Multi Application Solar Telescope). The scintillometer consists of a miniature telescope, termed as micro telescope (4mm aperture, 15mm focal length) mounted on a drive which tracks the Sun continuously, associated amplifiers and a data acquisition system. A photodiode is used as the detector. The telescope along with detector was obtained from National Solar Observatory (NSO), and is similar to the one used for Advanced Technology Solar Telescope (ATST) site survey. At USO we developed the amplifier and data acquisition system for the scintillometer. A 24-bit analog to digital converter based system was designed, assembled, tested and used as the data acquisition system (DAS). In this paper, we discuss the instrumentation and present the initial results.

Gupta, Sudhir Kumar; Mathew, Shibu K.; Venkatakrishnan, P.

2006-09-01

325

Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes  

NASA Astrophysics Data System (ADS)

Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex "roll-up" of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) "optical flow" code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s-1, which is supersonic for a ~10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s-1. Typical lifetimes range from 300 to 1000 s (~5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km2 s-1 reaching maximum projected areas from 2 to 15 Mm2. Maximum contrast of the dark flows relative to the bright prominence plasma in SOT images is negative and ranges from -10% for smaller flows to -50% for larger flows. Passive scalar "cork movies" derived from NAVE measurements show that prominence plasma is entrained by the upflows, helping to counter the ubiquitous downflow streams in the prominence. Plume formation shows no clear temporal periodicity. However, it is common to find "active cavities" beneath prominences that can spawn many upflows in succession before going dormant. The mean flow recurrence time in these active locations is roughly 300-500 s (5-8 minutes). Locations remain active on timescales of tens of minutes up to several hours. Using a column density ratio measurement and reasonable assumptions on plume and prominence geometries, we estimate that the mass density in the dark cavities is at most 20% of the visible prominence density, implying that a single large plume could supply up to 1% of the mass of a typical quiescent prominence. We hypothesize that the plumes are generated from a Rayleigh-Taylor instability taking place on the boundary between the buoyant cavities and the overlying prominence. Characteristics, such as plume size and frequency, may be modulated by the strength and direction of the cavity magnetic field relative to the prominence magnetic field. We conclude that buoyant plumes are a source of quiescent prominence mass as well as a mechanism by which prominence plasma is advected upward, countering constant gravitational drainage.

Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

2010-06-01

326

Astrometric and Photometric Observations of Solar System Bodies with Telescopes of Pulkovo Observatory  

E-print Network

with MTM-500M telescope, placed on Mount Astronomical Station of Pulkovo observatory (Northern Caucasus in the Mount Astronomical station of Pulkovo Observatory at Northern Caucasus ( = 42° 40', = 43° 44', h = 2070

Boyer, Edmond

327

A normal incidence, high resolution X-ray telescope for solar coronal observations  

NASA Technical Reports Server (NTRS)

Efforts directed toward the completion of an X-ray telescope assembly design, the procurement of major components, and the coordination of optical fabrication and X-ray multilayer testing are reported.

Golub, L.

1984-01-01

328

Synthetic aperture systems; Proceedings of the Meeting, San Diego, CA, August 25, 26, 1983  

NASA Astrophysics Data System (ADS)

Synthetic aperture concepts are discussed, taking into account a synthetic aperture beam control system, a coherent optical system of modular imaging collectors providing an approach for a large aperture high angular resolution telescope in space, multimirror telescope alignment systems which employ fan beams and translation insensitive interferometers, translation insensitive heterodyne interferometers, and a synthetic aperture phase measurement system using a metering rod bridge with corner cubes. Topics related to design, simulation, and analysis are also explored, giving attention to a physical understanding of synthetic aperture arrays via simple models, design and performance of ranging telescopes, performance and phasing of multiline synthetic apertures, a computer model for evaluating synthetic aperture propogation, image-plane phase sensing for phased array telescopes, the testing of large telescope systems using multiple subapertures, and the influence of higher order noise in wavefront reconstruction. Synthetic aperture experiments are also considered.

Fender, J. S.

1984-01-01

329

Ultra high resolution images of the solar chromosphere and corona using coordinated rocket and balloon observations  

NASA Technical Reports Server (NTRS)

A discussion is presented of the scientific objectives that can be pursued by simultaneous coronal/chromospheric observation with the Multi-Spectral Solar Telescope Array (MSSTA), and a new balloon-borne observatory called the Ultra-High Resolution Vacuum Ultraviolet Spectroheliograph (UHRVS). Attention is given to the proposed UHRVS observatory, which will incorporate two instruments, a 65-cm aperture telescope with narrowband filters for high resolution photographic and photoelectric spectroheliograms, and a very high resolution spectrograph which uses a 40-cm aperture telescope. The capabilities of the MSSTA, and the joint UHRVS/MSSTA observing program that is envisioned are reviewed.

Walker, Arthur B. C., Jr.; Timothy, J. G.; Hoover, Richard B.; Barbee, Troy W., Jr.

1993-01-01

330

New Solar System Researches expected by a New Telescope Project at Mt. Haleakala, Hawaii  

NASA Astrophysics Data System (ADS)

We Tohoku University starts the project for the new ground-based telescope dedicated to planets and exoplanets, in collaboration with the Institute for Astronomy of University of Hawaii(IfA/UH) and ETH Zurich. The summit of Mt. Haleakala in Maui, Hawaii is one of the best sites with clear skies, good seeing, and low humidity conditions as well as good accessibility despite its high altitude (elv. 3,000m). Haleakala High Altitude Observatory is operated by IfA/UH, and we have been making observation of planets there since 2000. Currently, our observation facility consists of a 40cm telescope. We have been making observations of faint atmospheric and plasma features around bright planets, Io plasma torus, Mercury and Lunar sodium tail, and so on. Atmospheric escapes from Mars and Venus, the exoplanets close to mother stars are also possible future important topics. When we try to observe those faint emissions surrounding the bright objects, intense scattered light causes a serious problem. The new telescope shall avoid the diffraction due to a spider structure that holds a secondary mirror and to minimize the scattered light from mirror surfaces as far as possible. Such telescope with a wide dynamic range dedicated to planetary and exoplanetary sciences does not exist yet. The project, called PLANETS (Poralized Light from Atmospheres of Nearby Extra Terrestrial Planets), develops a new telescope (tentatively named as JHET; Japan Hawaii Europe Telescope) which consists of an off-axis primary mirror with a diameter of 1.8m, and Gregorian optics on an equatorial mount. State-of-art adaptive optics and masking technologies will also be adopted to eliminate the scattering light. This telescope will enables us to do spectro-polarimetric observations and faint plasma and atmospheres around the bright bodies. We will introduce the progress of our ground-based observations and the future plan involving the wide area of the international communities.

Kagitani, Masato; Okano, S.; Kasaba, Y.; Kuhn, J.; Berdyugina, S.

2009-09-01

331

The process of data formation for the Spectrometer/Telescope for Imaging X-rays (STIX) in Solar Orbiter  

E-print Network

The Spectrometer/Telescope for Imaging X-rays (STIX) is a hard X-ray imaging spectroscopy device to be mounted in the Solar Orbiter cluster with the aim of providing images and spectra of solar flaring regions at different photon energies in the range from a few keV to around 150 keV. The imaging modality of this telescope is based on the Moire pattern concept and utilizes 30 sub-collimators, each one containing a pair of co-axial grids. This paper applies Fourier analysis to provide the first rigorous description of the data formation process in STIX. Specifically, we show that, under first harmonic approximation, the integrated counts measured by STIX sub-collimators can be interpreted as specific spatial Fourier components of the incoming photon flux, named visibilities. Fourier analysis also allows the quantitative assessment of the reliability of such interpretation. The description of STIX data in terms of visibilities has a notable impact on the image reconstruction process, since it fosters the applic...

Giordano, Sara; Piana, Michele; Massone, Anna Maria

2014-01-01

332

Formation metrology and control for large separated optics space telescopes  

NASA Technical Reports Server (NTRS)

In this paper we present formation flying performance analysis initial results for a representative large space telescope composed of separated optical elements [Mett 02]. A virtual-structure construct (an equivalent rigid body) is created by unique metrology and control that combines both centralized and decentralized methods. The formation may be in orbit at GEO for super-resolution Earth observation, as in the case of Figure 1, or it may be in an Earth-trailing orbit for astrophysics, Figure 2. Extended applications are envisioned for exo-solar planet interferometric imaging by a formation of very large separated optics telescopes, Figure 3. Space telescopes, with such large apertures and f/10 to f/100 optics, are not feasible if connected by massive metering structures. Instead, the new virtual-structure paradigm of information and control connectivity between the formation elements provides the necessary spatial rigidity and alignment precision for the telescope.

Mettler, E.; Quadrelli, M.; Breckenridge, W.

2002-01-01

333

Roof aperture system for selective collection and control of solar energy for building heating, cooling and daylighting  

DOEpatents

The amount of building heating, cooling and daylighting is controlled by at least one pair of solar energy passing panels, with each panel of the pair of panels being exposed to a separate direction of sun incidence. A shutter-shade combination is associated with each pair of panels and the shutter is connected to the shade so that rectilinear movement of the shutter causes pivotal movement of the shade.

Sanders, William J. (Kansas City, KS); Snyder, Marvin K. (Overland Park, KS); Harter, James W. (Independence, MO)

1983-01-01

334

The solar array-induced disturbance of the Hubble Space Telescope pointing system  

Microsoft Academic Search

The investigation of the vibrational disturbances of the Hubble Space Telescope that were discovered soon after deployment in orbit is described in detail. It was found that the disturbances were particularly evident during orbital day-night crossings, and that the magnitudes of the disturbances were considerably larger than the design jitter requirements. This paper describes the process by which the vibrations

C. L. Foster; M. L. Tinker; G. S. Nurre; W. A. Till

1995-01-01

335

Solar-array-induced disturbance of the Hubble space telescope pointing system  

Microsoft Academic Search

The investigation of the vibrational disturbances of the Hubble Space Telescope that were discovered soon after deployment in orbit is described in detail. It was found that the disturbances were particularly evident during orbital day-night crossings, and that the magnitude of the disturbances was considerably larger than the design jitter requirement. This paper describes the process by which the vibrations

Carlton L. Foster; Michael L. Tinker; Gerald S. Nurre; William A. Till

1995-01-01

336

The Hadean, Through a Glass Telescopically: Observations of Young Solar Analogs  

NASA Technical Reports Server (NTRS)

Investigations into the Earth's surface environment during the Hadean eon (prior to 3.8 Ga) are hampered by the paucity of the geological and geochemical record and the relative inaccessibility of better-preserved surfaces with possibly similar early histories (i.e., Mars). One approach is to observe nearby, young solar-mass stars as analogs to the Hadean Sun and its environment. A catalog of 38 G and early K stars within 25 pc was constructed based on main-sequence status, bolometric luminosity, lack of known stellar companions within 800 AU, and coronal X-ray luminosities commensurate with the higher activity of solar-mass stars <0.8 b.y. old. Spectroscopic data support the assignment of ages of 0.2 - 0.8 Ga for most of these stars. Observations of these objects will provide insight into external forces that influenced Hadean atmosphere, ocean, and surface evolution (and potential ecosystems), including solar luminosity evolution, the flux and spectrum of solar ultraviolet radiation, the intensity of the solar wind, and the intensity and duration of a late period of heavy bombardment. The standard model of solar evolution predicts a luminosity of 0.75 solar luminosity at the end of the Hadean, implying a terrestrial surface temperature inconsistent with the presence of liquid water and motivating atmospheric greenhouse models. An alternative model fo solar evolution that invokes mass loss, constructed to explain solar Li depletion, attenuates or reverses this luminosity evolution of the atmospheres of Earth and the other terrestrial planets. This model can be tested by Li abundance measurements. The continuum emission from stellar wind plasma during significant mass loss may be detectable at millimeter and radio wavelengths. The Earth (and Moon) experienced a period of intense bombardment prior to 3.8 Ga, long after accretion was completed in the inner solar system and possibly associated with the clearing of residual planetesimals in the outer solar system. Such a bombardment may have contributed volatiles and organics to the surface, but also have limited the appearacne of a biosphere. While planetary systems around solar systems cannot be detected directly with present technology, the thermal emission from the interplanetary dust generated during a similar heavy bombardment period can be. Midinfrared observations of a large uniform sample of solar analogs are used to constrain the frequency and duration of such events.

Gaidos, E. J.

1998-01-01

337

Submillimeter Telescopes  

NASA Astrophysics Data System (ADS)

The submillimeter band is a critical one for astronomy. It contains spectral and spatial information on very distant newly formed galaxies and on the early stages of star formation within gas clouds. Yet it is one of the few regions of the electromagnetic spectrum still to be made fully available to astronomy. This is in part due to the general difficulties of construction of detectors, receivers, and telescopes for these wavelengths and in part to the attenuating nature of the Earth's atmosphere. In recent years, optical style telescopes have become available, either on high mountain sites, or in the case of the NASA Kuiper Airborne Observatory (KAO) or Stratospheric Observatory for Infrared Astronomy (SOFIA) on board a high-altitude airplane. The James Clerk Maxwell telescope at 15 m and the Caltech Submillimeter Observatory (CSO) telescope at 10.4 m are both large enough to have developed the field. However, the ESA satellite Herschel has now provided the required space platform for complete spectral coverage and the Atacama Large Millimeter/Submillimeter Array (ALMA) the high spatial resolution, aperture synthesis, high-sensitivity platform.

Phillips, Thomas G.; Padin, Stephen; Zmuidzinas, Jonas

338

Challenges and Approach for Making the Top End Optical Assembly for the 4-meter Advanced Technology Solar Telescope  

NASA Astrophysics Data System (ADS)

L-3 Integrated Optical Systems (IOS) Division has been selected by the National Solar Observatory (NSO) to make the Top End Optical Assembly (TEOA) for the 4-meter Advanced Technology Solar Telescope (ATST) to operate at Haleakala, Maui. ATST will perform to a very high optical performance level in a difficult thermal environment. The TEOA, containing the 0.65-meter silicon carbide secondary mirror and support, mirror thermal management system, mirror positioning and fast tip-tilt system, field stop with thermally managed heat dump, thermally managed Lyot stop, safety interlock and control system, and support frame, operates in the "hot spot” at the prime focus of the ATST and so presents special challenges. In this paper, we will describe the L-3 IOS technical approach to meet these challenges, including subsystems for opto-mechanical positioning, rejected and stray light control, wavefront tip-tilt compensation, and thermal management. Key words: ATST, TEOA, L-3 IOS, thermal management, silicon carbide (SiC) mirrors, hexapods, solar astronomy

Canzian, Blaise; Barentine, J.; Hull, T.

2012-01-01

339

New Solar System Researches expected by a New Telescope Project at Mt. Haleakala, Hawaii  

Microsoft Academic Search

We Tohoku University starts the project for the new ground-based telescope dedicated to planets and exoplanets, in collaboration with the Institute for Astronomy of University of Hawaii(IfA\\/UH) and ETH Zurich. The summit of Mt. Haleakala in Maui, Hawaii is one of the best sites with clear skies, good seeing, and low humidity conditions as well as good accessibility despite its

Masato Kagitani; S. Okano; Y. Kasaba; J. Kuhn; S. Berdyugina

2009-01-01

340

Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with {sup 3}He Buffer Gas  

SciTech Connect

The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using {sup 3}He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with {sup 4}He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV < or approx. m{sub a} < or approx. 0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g{sub a}{gamma} < or approx. 2.3x10{sup -10} GeV{sup -1} at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m{sub a} < or approx. 1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

Arik, M.; Cetin, S. A.; Ezer, C.; Yildiz, S. C. [Dogus University, Istanbul (Turkey); Aune, S.; Ferrer-Ribas, E.; Giomataris, I.; Papaevangelou, T. [IRFU, Centre d'Etudes Nucleaires de Saclay (CEA-Saclay), Gif-sur-Yvette (France); Barth, K.; Borghi, S.; Davenport, M.; Elias, N.; Haug, F.; Laurent, J. M.; Niinikoski, T.; Silva, P. S.; Stewart, L. [European Organization for Nuclear Research (CERN), Geneve (Switzerland); Belov, A.; Gninenko, S. [Institute for Nuclear Research (INR), Russian Academy of Sciences, Moscow (Russian Federation); Braeuninger, H. [Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany)

2011-12-23

341

Telescopes and space exploration  

NASA Technical Reports Server (NTRS)

The necessity for different types of telescopes for astronomical investigations is discussed. Major findings in modern astronomy by ground-based and spaceborne telescopes are presented. Observations of the Crab Nebula, solar flares, interstellar gas, and the Black Hole are described. The theory of the oscillating universe is explored. Operating and planned telescopes are described.

Brandt, J. C.; Maran, S. P.

1976-01-01

342

A Scanning Hartmann Focus Test for the EUVI Telescopes aboard STEREO  

NASA Technical Reports Server (NTRS)

The Solar TErrestrial RElations Observatory (STEREO), the third mission in NASA's Solar Terrestrial Probes program, was launched in 2006 on a two year mission to study solar phenomena. STEREO consists of two nearly identical satellites, each carrying an Extreme Ultraviolet Imager (EUVI) telescope as part of the Sun Earth Connection Coronal and Heliospheric Investigation instrument suite. EUVI is a normal incidence, 98mm diameter, Ritchey-Chretien telescope designed to obtain wide field of view images of the Sun at short wavelengths (17.1-30.4nm) using a CCD detector. The telescope entrance aperture is divided into four quadrants by a mask near the secondary mirror spider veins. A mechanism that rotates another mask allows only one of these sub-apertures to accept light over an exposure. The EUVI contains no focus mechanism. Mechanical models predict a difference in telescope focus between ambient integration conditions and on-orbit operation. We describe an independent check of the ambient, ultraviolet, absolute focus setting of the EUVI telescopes after they were integrated with their respective spacecraft. A scanning Hartmann-like test design resulted from constraints implied by the EUVI aperture select mechanism. This inexpensive test was simultaneously coordinated with other NASA integration and test activities in a high-vibration, clean room environment. The total focus test error was required to be better than +/-0.05 mm. We describe the alignment and test procedure, sources of statistical and systematic error, and then the focus determination results using various algorithms. The results are consistent with other tests of focus alignment and indicate that the EUVI telescopes meet the ambient focus offset requirements. STEREO is functioning well on-orbit and the EUVI telescopes meet their on-orbit image quality requirements.

Ohl, Ray; Antonille, Scott; Aronstein, Dave; Dean, Bruce; Eichhorn, Bil; Frey, Brad; Kubalak, Dave; Shiri, Ron; Smith, Scott; Wilson, Mark; Redman, Kevin; Janssen, Douglas; d'Entremont, Joseph

2007-01-01

343

A CATALOG OF SOLAR X-RAY PLASMA EJECTIONS OBSERVED BY THE SOFT X-RAY TELESCOPE ON BOARD YOHKOH  

SciTech Connect

A catalog of X-ray plasma ejections (XPEs) observed by the Soft X-ray Telescope on board the Yohkoh satellite has been recently developed in the Astronomical Institute of University of Wroclaw. The catalog contains records of 368 events observed in years 1991-2001 including movies and cross-references to associated events like flares and coronal mass ejections (CMEs). One hundred sixty-three XPEs out of 368 in the catalog were not reported until now. A new classification scheme of XPEs is proposed in which morphology, kinematics, and recurrence are considered. The relation between individual subclasses of XPEs and the associated events was investigated. The results confirm that XPEs are strongly inhomogeneous, responding to different processes that occur in the solar corona. A subclass of erupting loop-like XPEs is a promising candidate to be a high-temperature precursor of CMEs.

Tomczak, M.; Chmielewska, E., E-mail: tomczak@astro.uni.wroc.pl, E-mail: chmielewska@astro.uni.wroc.pl [Astronomical Institute, University of Wroclaw, ul. Kopernika 11, PL-51-622 Wroclaw (Poland)

2012-03-01

344

A Future Large-Aperture UVOIR Space Observatory: Study Overview  

NASA Astrophysics Data System (ADS)

The scientific drivers for very high angular resolution coupled with very high sensitivity and wavefront stability in the UV and optical wavelength regime have been well established. These include characterization of exoplanets in the habitable zones of solar type stars, probing the physical properties of the circumgalactic medium around z < 2 galaxies, and resolving stellar populations across a broad range of galactic environments. The 2010 NRC Decadal Survey and the 2013 NASA Science Mission Directorate 30-Year Roadmap identified a large-aperture UVOIR observatory as a priority future space mission. Our joint NASA GSFC/JPL/MSFC/STScI team has extended several earlier studies of the technology and engineering requirements needed to design and build a single filled aperture 10-meter class space-based telescope that can enable these ambitious scientific observations. We present here an overview of our new technical work including a brief summary of the reference science drivers as well as in-depth investigations of the viable telescope architectures, the requirements on thermal control and active wavefront control systems, and the range of possible launch configurations.

Postman, Marc; Thronson, Harley A.; Feinberg, Lee; Redding, David; Stahl, H. Philip

2015-01-01

345

Journal of Atmospheric and Solar-Terrestrial Physics 67 (2005) 11711177 Modelling high-power large-aperture radar meteor trails  

E-print Network

-aperture radar meteor trails Lars P. Dyrud�, Licia Ray, Meers Oppenheim, Sigrid Close, Kelly Denney Center see high-power large-aperture (HPLA) radar observations of meteor phenomena called head echoes and non demonstrating that meteor trails are unstable to growth of Farley­Buneman gradient-drift (FBGD) waves

Oppenheim, Meers

346

The using of large ground-based low frequency radio telescopes for outer solar corona diagnostics  

Microsoft Academic Search

The interplanetary scintillations method is well developed at meter- decimeter wavelength for solar wind study. Potentially the decameter range can be convenient for implementing this method at large elongations, i.e. for studying the outer corona. During last years this method was evaluated by using largest decameter antennas UTR-2 and Nancay Decameter Array at new quantity and quality levels. New methods

A. A. Konovalenko; I. S. Falkovich; N. N. Kalinichenko; M. R. Olyak; I. N. Bubnov; A. Lecacheux; C. Rosolen; J.-L. Bougeret; H. O. Rucker; R. Leitinger

2003-01-01

347

Lower bound on number and sizes of telescopes in an optical array receiver for deep space optical communication  

NASA Astrophysics Data System (ADS)

Free-Space optical communication is expected to revolutionize the deep-space communication by providing the high bandwidth data support for future solar and planetary exploration missions. Due to the cost and up-gradation constraints, an earth-based receiver seems to be a viable option. A large telescope acting as an optical antenna is required at the receiver end to support the reasonable data rates (at least in 10s of Mbps range). An array of smaller telescopes connected to fabricate a larger photon-collecting aperture is an attractive architecture. In this research, performance analyses of different array architectures are evaluated for a deep-space interplanetary optical communication link between Mars and Earth with an objective to find a lower bound on the number and sizes of individual telescopes in the array receiver. The achievable data rates are calculated for opposition and conjunction phases of Mars-Earth orbit. Various deleterious factors, such as background noise and atmospheric turbulence are also modeled in the simulations. Total aperture size of various array architectures are kept at 10 m. The comparison of results for different array architectures show that the performance of a receiver employing an array comprising of 135 telescopes with 0.86 m aperture diameter each is almost equivalent to a single telescope with 10 m aperture diameter. Further, if the diameter is reduced below this limit, the performance degradation is substantial.

Hashmi, Ali J.; Eftekhar, Ali A.; Adibi, Ali; Amoozegar, Farid

2014-10-01

348

Power Challenges of Large Scale Research Infrastructures: the Square Kilometer Array and Solar Energy Integration; Towards a zero-carbon footprint next generation telescope  

E-print Network

The Square Kilometer Array (SKA) will be the largest Global science project of the next two decades. It will encompass a sensor network dedicated to radioastronomy, covering two continents. It will be constructed in remote areas of South Africa and Australia, spreading over 3000Km, in high solar irradiance latitudes. Solar Power supply is therefore an option to power supply the SKA and contribute to a zero carbon footprint next generation telescope. Here we outline the major characteristics of the SKA and some innovation approaches on thermal solar energy Integration with SKA prototypes.

Barbosa, Domingos; Ruiz, Valeriano; Silva, Manuel; Verdes-Montenegro, Lourdes; Santander-Vela, Juande; Maia, Dalmiro; Antón, Sonia; van Ardenne, Arnold; Vetter, Matthias; Kramer, Michael; Keller, Reinhard; Pereira, Nuno; Silva, Vitor

2012-01-01

349

Improved magnetogram calibration of Solar Magnetic Field Telescope and its comparison with the Helioseismic and Magnetic Imager  

NASA Astrophysics Data System (ADS)

In this paper, we try to improve the magnetogram calibration method of the Solar Magnetic Field Telescope (SMFT). The improved calibration process fits the observed full Stokes information, using six points on the profile of Fe I 5324.18 Ĺ line, and the analytical Stokes profiles under the Milne-Eddington atmosphere model, adopting the Levenberg-Marquardt least-squares fitting algorithm. In comparison with the linear calibration methods, which employs one point, there is a large difference in the strength of longitudinal field Bl and transverse field Bt, caused by the non-linear relationship, but the discrepancy is little in the case of inclination and azimuth. We conclude that it is better to deal with the non-linear effects in the calibration of Bl and Bt using six points. Moreover, in comparison with Solar Dynamics Observatory/Helioseismic and Magnetic Imager (HMI), SMFT has larger stray light and acquires less magnetic field strength. For vector magnetic fields in two sunspot regions, the magnetic field strength, inclination and azimuth angles between SMFT and HMI are roughly in agreement, with the linear fitted slopes of 0.73/0.7, 0.95/1.04 and 0.99/1.1. In the case of pores and quiet regions (Bl < 600 G), the fitted slopes of the longitudinal magnetic field strength are 0.78 and 0.87, respectively.

Bai, X. Y.; Deng, Y. Y.; Teng, F.; Su, J. T.; Mao, X. J.; Wang, G. P.

2014-11-01

350

Radio telescopes of large resolving power  

Microsoft Academic Search

The method of aperture synthesis is discussed, and several facilities using the method, as well as some results obtained with them, are described. A brief historical view of the development leading up to the design of aperture synthesis telescopes is given. Apparatus described includes the one-arm, one-movable-point telescope built by Blythe in 1954 and the half-mile, one-mile, and 5-km telescopes.

M. Ryle

1975-01-01

351

High-Resolution Observations of Limb Spicules from the Transition Region and Coronal Explorer and the Swedish Solar Telescope  

NASA Astrophysics Data System (ADS)

We observed spicules at the solar limb with TRACE and the Swedish Solar Telescope on La Palma for four-day intervals in 2004 and 2005 as well as simultaneous SUMER/SOHO observations in 2004. We are evaluating the apparent motion of individual spicules to infer chromospheric heat flow and mass transfer and to improve the statistics of basic spicule parameters including height, velocity, and inclination. We use the highest available cadence to measure height vs. time curves, using parabolic and linear fits to extract average maximum heights and apparent velocities of rise and descent. Our semiautomatic measurements of several dozen individual Ca II H spicules find an average height of 7610 ± 20 km based on ballistic fits and 7990 ± 80 km based on linear fits, with average velocities 8.7 ± 0.2 km/s ascending and 5.6 ± 0.1 km/s descending. Our TRACE data include observations at 1600 Ĺ, 171 Ĺ, and Lyman-alpha; our SST observations using Lockheed Martin's SOUP include H-alpha (four wing wavelengths to measure velocities) and Ca II H. We are investigating the relationships between spicule height and intensity to search for evidence of sheathed vs. monolithic spicule models, and analyzing ionization fadeout vs. velocity reversals for limiting spicule heights. A third yearly session of simultaneous TRACE/SST observations is scheduled.We thank S. P. Souza, B. De Pontieu, L. Golub, and J. Cirtain; earlier collaboration by D. B. Seaton, J. P. Shoer, D. L. Butts, and J. W. Gangestad; as well as the Royal Swedish Academy of Sciences. Support was provided by a NASA/Solar-Terrestrial Guest Investigator Grant for TRACE (NNG04GK44G), from Sigma Xi, and from the NASA/Massachusetts Space Grant.

Westbrook, Owen; Pasachoff, J. M.; Kozarev, K. A.; Yee, J.

2006-06-01

352

HILT: a heavy ion large area proportional counter telescope for solar and anomalous cosmic rays  

Microsoft Academic Search

The HILT sensor has been designed to measure heavy ion elemental abundances, energy spectra, and direction of incidence in the mass range from helium to iron and in the energy range 4-250 MeV\\/nucleon. With its large geometric factor of 60 cm2 sr the sensor is optimized to provide compositional and spectral measurements for low-intensity cosmic rays, i.e., for small solar

Berndt Klecker; Dietrich Hovestadt; M. Scholer; H. Arbinger; M. Ertl; H. Kaestle; E. Kuenneth; P. Laeverenz; E. Seidenschwang; J. B. Blake; N. Katz; D. Mabry

1993-01-01

353

Infrared, adaptive, and synthetic aperture optical systems  

Microsoft Academic Search

This book contains 24 selections. Some of the titles are: Generating, grinding, and figuring advanced optical elements; Survey of material for an infrared-opaque coating; Parametric study of various synthetic aperture telescope configurations for coherent imaging applications; and Zone plates for optical sensor applications.

R. B. Johnson; W. L. Wolfe; J. S. Fender

1986-01-01

354

Discovery of Finely Structured Dynamic Solar Corona Observed in the Hi-C Telescope  

NASA Astrophysics Data System (ADS)

In the Summer of 2012, the High-resolution Coronal Imager (Hi-C) flew on board a NASA sounding rocket and collected the highest spatial resolution images ever obtained of the solar corona. One of the goals of the Hi-C flight was to characterize the substructure of the solar corona. We therefore examine how the intensity scales from AIA resolution to Hi-C resolution. For each low-resolution pixel, we calculate the standard deviation in the contributing high-resolution pixel intensities and compare that to the expected standard deviation calculated from the noise. If these numbers are approximately equal, the corona can be assumed to be smoothly varying, i.e., have no evidence of substructure in the Hi-C image to within Hi-C's ability to measure it given its throughput and readout noise. A standard deviation much larger than the noise value indicates the presence of substructure. We calculate these values for each low-resolution pixel for each frame of the Hi-C data. On average, 70% of the pixels in each Hi-C image show no evidence of substructure. The locations where substructure is prevalent is in the moss regions and in regions of sheared magnetic field. We also find that the level of substructure varies significantly over the roughly 160 s of the Hi-C data analyzed here. This result indicates that the finely structured corona is concentrated in regions of heating and is highly time dependent.

Winebarger, Amy R.; Cirtain, Jonathan; Golub, Leon; DeLuca, Edward; Savage, Sabrina; Alexander, Caroline; Schuler, Timothy

2014-05-01

355

The Substructure of the Solar Corona Observed in the Hi-C Telescope  

NASA Astrophysics Data System (ADS)

In the summer of 2012, the High-resolution Coronal Imager (Hi-C) flew aboard a NASA sounding rocket and collected the highest spatial resolution images ever obtained of the solar corona. One of the goals of the Hi-C flight was to characterize the substructure of the solar corona. We therefore calculate how the intensity scales from a low-resolution (AIA) pixels to high-resolution (Hi-C) pixels for both the dynamic events and “background” emission (meaning, the steady emission over the 5 minutes of data acquisition time). We find there is no evidence of substructure in the background corona; the intensity scales smoothly from low-resolution to high-resolution Hi-C pixels. In transient events, however, the intensity observed with Hi-C is, on average, 2.6 times larger than observed with AIA. This increase in intensity suggests that AIA is not resolving these events. This result suggests a finely structured dynamic corona embedded in a smoothly varying background.

Winebarger, Amy R.; Cirtain, Jonathan W.; Golub, Leon; DeLuca, Ed; Savage, Sabrina; Alexander, Caroline; Schuler, Timothy

2014-06-01

356

Cost Modeling for Space Telescope  

NASA Technical Reports Server (NTRS)

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

Stahl, H. Philip

2011-01-01

357

WIDESPREAD NANOFLARE VARIABILITY DETECTED WITH HINODE/X-RAY TELESCOPE IN A SOLAR ACTIVE REGION  

SciTech Connect

It is generally agreed that small impulsive energy bursts called nanoflares are responsible for at least some of the Sun's hot corona, but whether they are the explanation for most of the multimillion-degree plasma has been a matter of ongoing debate. We present here evidence that nanoflares are widespread in an active region observed by the X-Ray Telescope on board the Hinode mission. The distributions of intensity fluctuations have small but important asymmetries, whether taken from individual pixels, multipixel subregions, or the entire active region. Negative fluctuations (corresponding to reduced intensity) are greater in number but weaker in amplitude, so that the median fluctuation is negative compared to a mean of zero. Using Monte Carlo simulations, we show that only part of this asymmetry can be explained by Poisson photon statistics. The remainder is explainable through a tendency for exponentially decreasing intensity, such as would be expected from a cooling plasma produced from a nanoflare. We suggest that nanoflares are a universal heating process within active regions.

Terzo, Sergio; Reale, Fabio; Miceli, Marco [Dipartimento di Fisica, Universita di Palermo, Sezione di Astronomia, Piazza del Parlamento 1, 90134 Palermo (Italy); Klimchuk, James A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kano, Ryouhei; Tsuneta, Saku, E-mail: terzo@astropa.unipa.it [National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan)

2011-08-01

358

Mass and Energy of Erupting Solar Plasma Observed with the X-Ray Telescope on Hinode  

NASA Astrophysics Data System (ADS)

We investigate seven eruptive plasma observations by Hinode/XRT. Their corresponding EUV and/or white light coronal mass ejection features are visible in some events. Five events are observed in several passbands in X-rays, which allows for the determination of the eruptive plasma temperature using a filter ratio method. We find that the isothermal temperatures vary from 1.6 to 10 MK. These temperatures are an average weighted toward higher temperature plasma. We determine the mass constraints of eruptive plasmas by assuming simplified geometrical structures of the plasma with isothermal plasma temperatures. This method provides an upper limit to the masses of the observed eruptive plasmas in X-ray passbands since any clumping causes the overestimation of the mass. For the other two events, we assume the temperatures are at the maximum temperature of the X-ray Telescope (XRT) temperature response function, which gives a lower limit of the masses. We find that the masses in XRT, ~3 × 1013-5 × 1014 g, are smaller in their upper limit than the total masses obtained by LASCO, ~1 × 1015 g. In addition, we estimate the radiative loss, thermal conduction, thermal, and kinetic energies of the eruptive plasma in X-rays. For four events, we find that the thermal conduction timescales are much shorter than the duration of eruption. This result implies that additional heating during the eruption may be required to explain the plasma observations in X-rays for the four events.

Lee, Jin-Yi; Raymond, John C.; Reeves, Katharine K.; Moon, Yong-Jae; Kim, Kap-Sung

2015-01-01

359

Cooling Technology for Large Space Telescopes  

Microsoft Academic Search

NASA's New Millennium Program funded an effort to develop a system cooling technology, which is applicable to all future infrared, sub-millimeter and millimeter cryogenic space telescopes. In particular, this technology is necessary for the proposed large space telescope Single Aperture Far-Infrared Telescope (SAFIR) mission. This technology will also enhance the performance and lower the risk and cost for other cryogenic

Michael DiPirro; Paul Cleveland; Dale Durand; Andy Klavins; Danniella Muheim; Christopher Paine; Mike Petach; Domenick Tenerelli; Jason Tolomeo; Keith Walyus

360

Solar observing facilities  

Microsoft Academic Search

An overview is given of current and planned ground-based solar telescopes and instruments, balloon-borne and suborbital solar telescopes, and solar and heliospheric space missions. These observing facilities operate in all areas of solar physics, from the solar interior to interplanetary space and from regimes of high energy to observations requiring high resolution. The next generation of solar telescopes and instruments

B. Fleck; C. U. Keller

2003-01-01

361

Toward Active X-ray Telescopes II  

NASA Technical Reports Server (NTRS)

In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the sensitivity for detection of cosmic x-ray sources has improved by ten orders of magnitude. Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope. The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (greater than 1 m2) and finer angular resolution (less than 1.). Combined with the special requirements of grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically challenging.requiring precision fabrication, alignment, and assembly of large areas (greater than 100 m2) of lightweight (approximately 1 kg m2 areal density) mirrors. Achieving precise and stable alignment and figure control may entail active (in-space adjustable) x-ray optics. This paper discusses relevant programmatic and technological issues and summarizes progress toward active x-ray telescopes.

O'Dell, Stephen L.; Aldroft, Thomas L.; Atkins, Carolyn; Button, Timothy W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peter; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Johnson-Wilke, Raegan L.; Kolodziejczak, Jeffery J.; Lillie, Charles F.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Sanmartin, Daniel Rodriguez; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan E.; Ulmer, Melville P.; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

2012-01-01

362

Toward active x-ray telescopes II  

NASA Astrophysics Data System (ADS)

In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the observation time required to achieve a given sensitivity has decreased by eight orders of magnitude. Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope, culminating with the exquisite subarcsecond imaging performance of the Chandra X-ray Observatory. The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (< 1 m2) and comparable or finer angular resolution (< 1?). Combined with the special requirements of grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically challenging—requiring precision fabrication, alignment, and assembly of large areas (< 200 m2) of lightweight (? 1 kg m-2 areal density) mirrors. Achieving precise and stable alignment and figure control may entail active (in-space adjustable) x-ray optics. This paper discusses relevant programmatic and technological issues and summarizes current progress toward active x-ray telescopes.

O'Dell, Stephen L.; Aldcroft, Thomas L.; Atkins, Carolyn; Button, Timothy W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peter; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Johnson-Wilke, Raegan L.; Kolodziejczak, Jeffery J.; Lillie, Charles F.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Rodriguez Sanmartin, Daniel; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan E.; Ulmer, Melville P.; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

2012-10-01

363

Hubble, a view to the edge of space : telescope tour  

NSDL National Science Digital Library

Eight thumbnail images of key features of the Hubble Space Telescope surround this drawing of Hubble. Users can move their mouse over the image of a feature to reveal both the location(s) of the feature and a description of its function. The solar arrays, communications antennae, aperture door, and fine gauge sensors are among the featured parts. Three of the eight feature descriptions offer users the option to link to additional information about these parts of Hubble. Links to more information and to activities about Hubble are provided at the bottom of the page. Copyright 2005 Eisenhower National Clearinghouse

Exploratorium

2001-01-01

364

Solar prominences in the extreme ultraviolet as observed from the Apollo Telescope Mount  

NASA Technical Reports Server (NTRS)

Observations of quiescent solar prominences with the Harvard College Observatory spectrometer aboard Skylab show that prominence material is optically thick in the Lyman alpha line and the Lyman continuum. The color temperature of the Lyman continuum has a mean of 6600 K and an upward gradient toward the top of the prominence. The departure coefficient of the ground state of hydrogen is found to be of the order of unity, as expected from theory. The optical depth of the C III sheath region is determined directly from the observation of the limb through the prominence and is used to infer the mean electron density and the temperature gradient of the sheath. The result implies that the sheath density is about 0.4, and the temperature gradient about 1.4 times the respective value in the C III transition zone of the quiet sun. The C III triplet-singlet ratio for the prominence is found to give a density compatible, within the uncertainty of the atomic parameters, with the density obtained from the optical depth.

Schmahl, E. J.; Foukal, P. V.; Noyes, R. W.; Reeves, E. M.; Timothy, J. G.; Vernazza, J. E.; Withbroe, G. L.; Huber, M. C. E.

1974-01-01

365

Electron microscope aperture system  

NASA Technical Reports Server (NTRS)

An electron microscope including an electron source, a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the specimen, and an objective lens having an annular objective aperture, for focusing electrons passing through the specimen onto an image plane are described. The invention also entails a method of making the annular objective aperture using electron imaging, electrolytic deposition and ion etching techniques.

Heinemann, K. (inventor)

1976-01-01

366

Ground-based solar facilities in the U.S.A.  

NASA Astrophysics Data System (ADS)

In this review, we present the status of new ground-based facilities for optical and radio observations of the Sun in the United States. The 4-meter aperture Advanced Technology Solar Telescope (ATST) under the stewardship of the National Solar Observatory (NSO) has successfully completed its design phase and awaits funding approval. The 1.6-meter aperture New Solar Telescope (NST) at Big Bear Solar Observatory (BBSO) is currently under construction. Complementing these optical telescopes is the Frequency Agile Solar Radiotelescope (FASR) an instrument for dynamic broadband imaging spectroscopy covering a multitude of radio frequencies from 50 MHz to 20 GHz. Imaging spectroscopy and polarimetry are common features of these telescopes, which will provide new insight regarding the evolution and nature of solar magnetic fields. High-resolution observations of solar activity, bridging the solar atmosphere from the photosphere to the corona, will be obtained with a dedicated suite of instruments. Special emphasis of this review will be put on the interplay between instrumentation and scientific discovery.

Denker, C.; Gary, D. E.; Rimmele, T. R.

367

Sub-arcsec X-Ray Telescope for Imaging The Solar Corona In the 0.25 - 1.2 keV Band  

NASA Technical Reports Server (NTRS)

We have developed an X-ray telescope that uses a new technique for focusing X-rays with grazing incidence optics. The telescope was built with spherical optics for all of its components, utilizing the high quality surfaces obtainable when polishing spherical (as opposed to aspherical) optics. We tested the prototype X-ray telescope in the 300 meter vacuum pipe at White Sands Missile Range, NM. The telescope features 2 degee graze angles with tungsten coatings, yielding a bandpass of 0.25-1.5 keV with a peak effective area of 0.8 sq cm at 0.83 keV. Results from X-ray testing at energies of 0.25 keV and 0.93 keV (C-K and Cu-L) verify 0.5 arcsecond performance at 0.93 keV. Results from modeling the X-ray telescope's response to the Sun show that the current design would be capable of recording 10 half arcsecond images of a solar active region during a 300 second NASA sounding rocket flight.

Gallagher, Dennis; Cash, Webster; Jelsma, Schuyler; Farmer, Jason

1996-01-01

368

Surveys, Temporal Variability, and the Las Cumbres Observatory Global Telescope  

NASA Astrophysics Data System (ADS)

Upcoming wide-field surveys such as Pan-STARRS, LSST, and Skymapper will detect large numbers of objects that vary photometrically, or that move. These objects will include small bodies in the solar systema, eclipsing binary stars, transiting extrasolar planets, pulsating stars, dwarf novae, novae, supernovae, active galactic nuclei, and quite possibly other transient phenomena for which we have no names as yet. Although they will be a fertile source of such transient detections, wide-field surveys themselves ordinarily will have neither the observing cadence nor the (e.g., spectroscopic) observing capabilities to perform adequate follow-up observations of these variable objects. The Las Cumbres Observatory Global Telescope (LCOGT) will be a global network of moderate-aperture (2m and smaller) telescopes, instrumented and interconnected so as to facilitate such in-depth variability studies. The LCOGT now operates the two 2m Faulkes Telescopes: FT North located on the island of Maui, and FT South at the Siding Spring site in Australia. These telescopes will anchor a network of about 7 clusters of 1m-class telescopes, each cluster containing 4 telescopes. First-light instruments will provide visible-light and NIR imaging; spectroscopic capabilities will come later, and will likely include both low- and high-resolution visible-light spectrographs. Scheduling and coordination of observations will be provided from a central site, in pursuit of a single set of scientific goals.

Brown, Tim; Rosing, W. E.; Baliber, N.; Hidas, M.; Street, R.

2007-05-01

369

Cooling Technology for Large Space Telescopes  

NASA Technical Reports Server (NTRS)

NASA's New Millennium Program funded an effort to develop a system cooling technology, which is applicable to all future infrared, sub-millimeter and millimeter cryogenic space telescopes. In particular, this technology is necessary for the proposed large space telescope Single Aperture Far-Infrared Telescope (SAFIR) mission. This technology will also enhance the performance and lower the risk and cost for other cryogenic missions. The new paradigm for cooling to low temperatures will involve passive cooling using lightweight deployable membranes that serve both as sunshields and V-groove radiators, in combination with active cooling using mechanical coolers operating down to 4 K. The Cooling Technology for Large Space Telescopes (LST) mission planned to develop and demonstrate a multi-layered sunshield, which is actively cooled by a multi-stage mechanical cryocooler, and further the models and analyses critical to scaling to future missions. The outer four layers of the sunshield cool passively by radiation, while the innermost layer is actively cooled to enable the sunshield to decrease the incident solar irradiance by a factor of more than one million. The cryocooler cools the inner layer of the sunshield to 20 K, and provides cooling to 6 K at a telescope mounting plate. The technology readiness level (TRL) of 7 will be achieved by the active cooling technology following the technology validation flight in Low Earth Orbit. In accordance with the New Millennium charter, tests and modeling are tightly integrated to advance the technology and the flight design for "ST-class" missions. Commercial off-the-shelf engineering analysis products are used to develop validated modeling capabilities to allow the techniques and results from LST to apply to a wide variety of future missions. The LST mission plans to "rewrite the book" on cryo-thermal testing and modeling techniques, and validate modeling techniques to scale to future space telescopes such as SAFIR.

DiPirro, Michael; Cleveland, Paul; Durand, Dale; Klavins, Andy; Muheim, Daniella; Paine, Christopher; Petach, Mike; Tenerelli, Domenick; Tolomeo, Jason; Walyus, Keith

2007-01-01

370

Solar astronomy  

NASA Technical Reports Server (NTRS)

An overview is given of modern solar physics. Topics covered include the solar interior, the solar surface, the solar atmosphere, the Large Earth-based Solar Telescope (LEST), the Orbiting Solar Laboratory, the High Energy Solar Physics mission, the Space Exploration Initiative, solar-terrestrial physics, and adaptive optics. Policy and related programmatic recommendations are given for university research and education, facilitating solar research, and integrated support for solar research.

Rosner, Robert; Noyes, Robert; Antiochos, Spiro K.; Canfield, Richard C.; Chupp, Edward L.; Deming, Drake; Doschek, George A.; Dulk, George A.; Foukal, Peter V.; Gilliland, Ronald L.

1991-01-01

371

The application of linear actuators for telescope pointing control  

Microsoft Academic Search

A study team at MSFC has conceptually designed two lunar-based telescopes, a 16 m aperture Large Lunar Telescope (LLT) and a 4 m Cluster Telescope Experiment (CTE). The CTE serves as a technology tested for the LLT. The CTE utilizes a hexapod telescope mount to obtain a small gimbal angle that significantly extends the viewing space and observation time from

C. K. Carrington; B. G. Davis

1992-01-01

372

The 5-km Radio Telescope at Cambridge  

Microsoft Academic Search

Radio astronomers can now map the sky with a resolution comparable to that of the best optical telescopes. This latest advance in aperture synthesis technology should yield important new evidence on the physics of radio galaxies, quasars and supernova remnants.

Martin Ryle

1972-01-01

373

Observations of Microwave Fine Structures by the Badary Broadband Microwave Spectropolarimeter and the Siberian Solar Radio Telescope  

NASA Astrophysics Data System (ADS)

Observations of solar radio bursts with fine temporal and spectral structures may provide important information about the physical processes occurring in the solar corona. The Badary Broadband Microwave Spectropolarimeter instrument has been regularly observing solar radio emission in the 3.8 - 8.2 GHz range since August 2010. We present the statistical analysis of spectral and temporal fine structures of microwave emission during solar flares that occurred in 2011 - 2012. Fine structures were detected both during solar flares accompanied by microwave broadband emission and during weak solar flares when the microwave broadband emission was absent. A total of 235 events of solar origin were found and analyzed.

Zhdanov, D. A.; Zandanov, V. G.

2015-01-01

374

The South Pole Telescope  

SciTech Connect

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

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

2004-11-04

375

LUTE telescope structural design  

NASA Technical Reports Server (NTRS)

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

Ruthven, Gregory

1993-01-01

376

The Spacewatch 1.8-meter Telescope  

NASA Astrophysics Data System (ADS)

The largest telescope in the world dedicated to the search for Earth-approaching asteroids and other previously unknown members of the solar system will soon be operational. Its 1.8-m aperture, large and sensitive CCD, and dedication to surveying will make it possible to find as many as 80,000 new asteroids per year. The mechanical design by Barr is optimized by finite-element analysis to provide high resonant frequencies. The mount is an altitude-azimuth type for compatibility with the mirror support cell contributed by the Multi-Mirror Telescope Observatory. Both axes are driven by DC servo motors directly coupled to friction rollers. The CCD instrument stage will also be rotated under computer control. The telescope was fabricated in the University Research Instrumentation Center (URIC). Construction of the building began on Kitt Peak on July 1, 1996. The optical configuration is f/2.7 folded prime focus with a flat secondary that locates the focal plane in the center of the optical truss near the altitude axis. This shortened the telescope enough to make the dome building affordable, and the flat secondary preserves the fast f/number of the primary mirror. The coma corrector designed by R. A. Buchroeder is a modified Klee design of 5 spherical lens elements plus a filter transmitting longward of the B bandpass. The filter greatly simplifies lens design and reduces sky background while not significantly reducing the brightness of asteroids. The distortion-free, flat, unvignetted field of view is 0.8 deg in diameter and the image scale is 1.0 arcsec/24 micron pixel. Construction of the Spacewatch Telescope has been funded by grants from the DoD Clementine Program, NASA, the University of Arizona Foundation, and other private and corporate donors.

Perry, M. L.; McMillan, R. S.; Barr, L. D.; Bressi, T. H.; Gehrels, T.

1996-09-01

377

Variable-aperture screen  

DOEpatents

Apparatus for separating material into first and second portions according to size including a plurality of shafts, a plurality of spaced disks radiating outwardly from each of the shafts to define apertures and linkage interconnecting the shafts for moving the shafts toward or away from one another to vary the size of the apertures while the apparatus is performing the separating function.

Savage, George M. (Richmond, CA)

1991-01-01

378

Rotating Aperture System  

DOEpatents

A rotating aperture system includes a low-pressure vacuum pumping stage with apertures for passage of a deuterium beam. A stator assembly includes holes for passage of the beam. The rotor assembly includes a shaft connected to a deuterium gas cell or a crossflow venturi that has a single aperture on each side that together align with holes every rotation. The rotating apertures are synchronized with the firing of the deuterium beam such that the beam fires through a clear aperture and passes into the Xe gas beam stop. Portions of the rotor are lapped into the stator to improve the sealing surfaces, to prevent rapid escape of the deuterium gas from the gas cell.

Rusnak, Brian (Livermore, CA); Hall, James M. (Livermore, CA); Shen, Stewart (Danville, CA); Wood, Richard L. (Santa Fe, NM)

2005-01-18

379

Corrective Optics For Camera On Telescope  

NASA Technical Reports Server (NTRS)

Assembly of tilted, aspherical circularly symmetric mirrors used as corrective optical subsystem for camera mounted on telescope exhibiting both large spherical wave-front error and inherent off-axis astigmatism. Subsystem provides unobscured camera aperture and diffraction-limited camera performance, despite large telescope aberrations. Generic configuration applied in other optical systems in which aberations deliberately introduced into telescopes and corrected in associated cameras. Concept of corrective optical subsystem provides designer with additional degrees of freedom used to optimize optical system.

Macenka, Steven A.; Meinel, Aden B.

1994-01-01

380

Optical Design for a New Off-Axis 1.6 m Solar Telescope (NST) at Big Bear  

E-print Network

Some technological improvements (high-speed computers, real-time systems for analyzing and controlling. A high-order Adaptive optics (AO) system will deliver light to the current and planned complement of BBSO-axis) pupil. Keywords: Optical Design, Off-Axis Telescope, Adaptive Optics 1. INTRODUCTION There are a few

Didkovsky, Leonid

381

Cost Modeling for Space Optical Telescope Assemblies  

NASA Technical Reports Server (NTRS)

Parametric cost models are used to plan missions, compare concepts and justify technology investments. This paper reviews an on-going effort to develop cost modes for space telescopes. This paper summarizes the methodology used to develop cost models and documents how changes to the database have changed previously published preliminary cost models. While the cost models are evolving, the previously published findings remain valid: it costs less per square meter of collecting aperture to build a large telescope than a small telescope; technology development as a function of time reduces cost; and lower areal density telescopes cost more than more massive telescopes.

Stahl, H. Philip; Henrichs, Todd; Luedtke, Alexander; West, Miranda

2011-01-01

382

The Largest Feasible Steerable Telescope  

NASA Astrophysics Data System (ADS)

Ever since Grote Reber built a 32-ft steerable dish in 1937, successive generations of radio astronomers world-wide have designed larger and larger fully steerable filled aperture radio telescopes to address a variety of astronomical questions. Paced by the giant 250-ft radio telescope that was built at Jodrell Bank, starting in the 1950’s NRAO, Caltech, and Smithsonian radio astronomers have discused the construction of a series of large steerable dishes ranging in size up to 600-ft in diameter. Although the need for a large steerable radio telescope was repeatedly recognized by the series of NRC decade reviews of astronomy, they were never given the highest priority and were never funded. Meanwhile, in the 1960s and 1970s the Parkes 64-m and the German 100-m telescopes became operational. A freak 1989 accident that caused the collapse of the 300-ft Green Bank transit telescope, led directly to the construction of the 100-m Green Bank Telescope with its novel unblocked aperture and adaptive surface, although by 1989, the 300-ft telescope had long outlived its designed lifetime, and had already been recommended for closure.

Kellermann, Kenneth I.; Bouton, E. N.

2014-01-01

383

Dielectric loaded aperture antennas.  

NASA Technical Reports Server (NTRS)

This paper describes a primarily experimental study of the effect of placing dielectric obstacles having various geometries directly upon the aperture of circular and rectangular waveguide antennas. It is found that plexiglas spheres, and in some cases plexiglas cubes, one to four wavelengths in dimension, produce directive patterns with low sidelobes. The measured gain in some cases is 6 dB greater than the gain of an optimum horn having an equal aperture size.

Croswell, W. F.; Chatterjee, J. S.

1972-01-01

384

APT: Aperture Photometry Tool  

NASA Astrophysics Data System (ADS)

Aperture Photometry Tool (APT) is software for astronomers and students interested in manually exploring the photometric qualities of astronomical images. It has a graphical user interface (GUI) which allows the image data associated with aperture photometry calculations for point and extended sources to be visualized and, therefore, more effectively analyzed. Mouse-clicking on a source in the displayed image draws a circular or elliptical aperture and sky annulus around the source and computes the source intensity and its uncertainty, along with several commonly used measures of the local sky background and its variability. The results are displayed and can be optionally saved to an aperture-photometry-table file and plotted on graphs in various ways using functions available in the software. APT is geared toward processing sources in a small number of images and is not suitable for bulk processing a large number of images, unlike other aperture photometry packages (e.g., SExtractor). However, APT does have a convenient source-list tool that enables calculations for a large number of detections in a given image. The source-list tool can be run either in automatic mode to generate an aperture photometry table quickly or in manual mode to permit inspection and adjustment of the calculation for each individual detection. APT displays a variety of useful graphs, including image histogram, and aperture slices, source scatter plot, sky scatter plot, sky histogram, radial profile, curve of growth, and aperture-photometry-table scatter plots and histograms. APT has functions for customizing calculations, including outlier rejection, pixel “picking” and “zapping,” and a selection of source and sky models. The radial-profile-interpolation source model, accessed via the radial-profile-plot panel, allows recovery of source intensity from pixels with missing data and can be especially beneficial in crowded fields.

Laher, Russ

2012-08-01

385

Analysis of telescope site selection for optical deep space network  

Microsoft Academic Search

The successful design of an optical deep space network (ODSN) greatly depends on the selection of optimal telescope sites. At the highest system level, there are two main factors to consider in the design of a global optical communications network for deep space applications: telescope size (i.e., aperture size) and the distance between stations. The size of the individual telescope

Sabino Piazzolla; Farid Amoozegar; Robert Cesarone

2004-01-01

386

Hubble Space Telescope  

NASA Technical Reports Server (NTRS)

An overview of the mission of the Hubble Space Telescope, a joint project between NASA and the European Space Agency which will be used to study deep space, as well as our solar system is presented. The video contains animations depicting the Hubble Space Telescope in orbit, as well as footage of scientists at the Space Telescope Science Institute making real time observations. The images Hubble acquires will be downloaded into a database that contains images of over 19,000,000 celestial objects called the Star Catalog.

1990-01-01

387

The Local Seeing Environment at Big Bear Solar Observatory  

NASA Astrophysics Data System (ADS)

The site survey for the Advanced Technology Solar Telescope (ATST) of the National Solar Observatory was initiated in 2002 to find the best location for a 4 m aperture solar telescope. At the end of a 4 year survey, three sites (Big Bear Solar Observatory [BBSO] in California, Mees Solar Observatory [MSO] on Haleakala, Maui, Hawaii, and Observatorio Roque de los Muchachos, on La Palma, Spain) were identified as excellent sites for high-resolution solar observations. MSO was ultimately chosen as the future ATST site. We present a subset of the ATST site survey data, focusing on the local seeing environment at BBSO. In particular, we are interested in the seeing characteristics at a mountain lake-site observatory, its relation to the local environment and climate, and its implications for the 1.6 m New Solar Telescope (NST) currently being built at BBSO. We find a close correlation of very good seeing conditions with the prevailing wind direction and speed. The observatory building, located at the end of a 300 m causeway, is surrounded by the cool waters of Big Bear Lake, which effectively suppress the ground-layer seeing. Very good seeing conditions from sunrise to sunset are a unique feature of BBSO, which makes it ideally suited for synoptic observations and sustained high-resolution studies of solar activity and space weather.

Verdoni, Angelo; Denker, Carsten

2007-07-01

388

Neutrino Telescopes  

SciTech Connect

Neutrino telescopes complement gamma ray telescopes in the observations of energetic astronomical sources as well as in searching for the dark matter. This paper gives the status of the current generation neutrino telescopes projects: Baikal, AMANDA, NESTOR, NEMO and ANTARES with particular emphasis on the ANTARES telescope in the Mediterranean Sea.

Carr, John [Centre de Physiques des Particules de Marseille, IN2P3/CNRS (France)

2005-02-21

389

Space Telescope.  

ERIC Educational Resources Information Center

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

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

390

Relating a Prominence Observed from the Solar Optical Telescope on the Hinode Satellite to Known 3-D Structures of Filaments  

NASA Astrophysics Data System (ADS)

We address only a first step in relating limb and disk observations by illustrating and comparing the spines and barbs of three different quiescent prominences and filaments observed in H? by three different telescopes. Although the appearance of the three quiescent prominences is quite different, we show that each consists of a spine, barbs extending from the spine, and arcs at the base of some of the curtains of barb threads.

Martin, S. F.; Panasenco, O.; Agah, Y.; Engvold, O.; Lin, Y.

2009-12-01

391

Astron. Nachr. / AN 331, No. 6, 636 639 (2010) / DOI 10.1002/asna.201011390 Scientific instrumentation for the 1.6 m New Solar Telescope in Big Bear  

E-print Network

instrumentation for the 1.6 m New Solar Telescope in Big Bear W. Cao1,2, , N. Gorceix2 , R. Coulter2 , K. Ahn3 , T, 323 Martin Luther King Blvd., Newark, NJ, U.S.A. 2 Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA, U.S.A. 3 Department of Physics and Astronomy, Seoul National University, Korea 4

392

Influence of the antenna diagram on a stellar interferometer that is suffering from telescope-pointing errors  

Microsoft Academic Search

We report our experimental investigations of the influence of differential telescope-pointing errors on data corruption in an optical stellar interferometer. This effect was investigated theoretically as a function of the telescope antenna diagram, which depends on the aperture diameter. Using a laboratory breadboard consisting of a three-telescope array, we carried out the experiments with various aperture diameters and complex objects.

Emmanuel Longueteau; Laurent Delage; Fra?ois Reynaud

2002-01-01

393

Solar Meridional Circulation from Doppler Shifts of the Fe I Line at 5250 Ĺ as Measured by the 150-foot Solar Tower Telescope at the Mt. Wilson Observatory  

NASA Astrophysics Data System (ADS)

Doppler shifts of the Fe I spectral line at 5250 Ĺ from the full solar disk obtained over the period 1986 to 2009 are analyzed to determine the circulation velocity of the solar surface along meridional planes. Simultaneous measurements of the Zeeman splitting of this line are used to obtain measurements of the solar magnetic field that are used to select low field points and impose corrections for the magnetically induced Doppler shift. The data utilized is from a new reduction that preserves the full spatial resolution of the original observations so that the circulation flow can be followed to latitudes of 80° N/S. The deduced meridional flow is shown to differ from the circulation velocities derived from magnetic pattern movements. A reversed circulation pattern is seen in polar regions for three successive solar minima. A surge in circulation velocity at low latitudes is seen during the rising phases of cycles 22 and 23.

Ulrich, Roger K.

2010-12-01

394

SOLAR MERIDIONAL CIRCULATION FROM DOPPLER SHIFTS OF THE Fe I LINE AT 5250 A AS MEASURED BY THE 150-FOOT SOLAR TOWER TELESCOPE AT THE MT. WILSON OBSERVATORY  

SciTech Connect

Doppler shifts of the Fe I spectral line at 5250 A from the full solar disk obtained over the period 1986 to 2009 are analyzed to determine the circulation velocity of the solar surface along meridional planes. Simultaneous measurements of the Zeeman splitting of this line are used to obtain measurements of the solar magnetic field that are used to select low field points and impose corrections for the magnetically induced Doppler shift. The data utilized is from a new reduction that preserves the full spatial resolution of the original observations so that the circulation flow can be followed to latitudes of 80{sup 0} N/S. The deduced meridional flow is shown to differ from the circulation velocities derived from magnetic pattern movements. A reversed circulation pattern is seen in polar regions for three successive solar minima. A surge in circulation velocity at low latitudes is seen during the rising phases of cycles 22 and 23.

Ulrich, Roger K. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562 (United States)

2010-12-10

395

Combining visibilities from the Giant Meterwave Radio Telescope and the Nancay Radio Heliograph: High dynamic range snapshot images of the solar corona at 327 MHz  

E-print Network

We report first results from an ongoing program of combining visibilities from the Giant Meterwave Radio Telescope (GMRT) and the Nancay Radio Heliograph (NRH) to produce composite snapshot images of the sun at meter wavelengths. We describe the data processing, including a specific multi-scale CLEAN algorithm. We present results of a) simulations for two models of the sun at 327 MHz, with differing complexity b) observations of a complex noise storm on the sun at 327 MHz on Aug 27 2002. Our results illustrate the capacity of this method to produce high dynamic range snapshot images when the solar corona has structures with scales ranging from the image resolution of 49" to the size of the whole sun. We find that we cannot obtain reliable snapshot images for complex objects when the visibilities are sparsely sampled.

Claude Mercier; Prasad Subramanian; Alain Kerdraon; Monique Pick; S. Ananthakrishnan; P. Janardhan

2005-08-31

396

A Space-Based Near-Earth Object Survey Telescope in Support of Human Exploration, Solar System Science, and Planetary Defense  

NASA Technical Reports Server (NTRS)

Human exploration of near-Earth objects (NEOs) beginning in 2025 is one of the stated objectives of U.S. National Space Policy. Piloted missions to these bodies would further development of deep space mission systems and technologies, obtain better understanding of the origin and evolution of our Solar System, and support research for asteroid deflection and hazard mitigation strategies. As such, mission concepts have received much interest from the exploration, science, and planetary defense communities. One particular system that has been suggested by all three of these communities is a space-based NEO survey telescope. Such an asset is crucial for enabling affordable human missions to NEOs circa 2025 and learning about the primordial population of objects that could present a hazard to the Earth in the future.

Abell, Paul A.

2011-01-01

397

A Low-Frequency Distributed Aperture Array for Radio Astronomy in Space  

NASA Astrophysics Data System (ADS)

The frequency band below 30 MHz is one of the last unexplored bands in radio astronomy. This band is well suited for studying the early cosmos at high hydrogen redshifts, the so-called dark ages, extragalactic surveys, (extra) solar planetary bursts, and high energy particle physics. In addition, space research such as space weather tomography, are also areas of scientific interest. Due to ionospheric scintillation (below 30MHz) and its opaqueness (below 15MHz), earth-bound radio astronomy observations in these bands are either severely limited in sensitivity and spatial resolution or entirely impossible. A radio telescope in space obviously would not be hampered by the Earth's ionosphere. In the past, several (limited) studies have been conducted to explore possibilities for such an array in space. These studies considered aperture synthesis arrays in space, at the back-side of the Moon, or a satellite constellation operating in a coherent mode. In 2009 an ESA project, Distributed Aperture Array for Radio Astronomy in Space (DARIS), set out to investigate the space-based radio telescope concept. The focus of this feasibility study is on a moderate size three-dimensional satellite constellation operating as a coherent large aperture synthesis array. This aperture synthesis array would consist of 5 to 50 antennas (satellites) having a maximum separation of 100 km. This study considers the main aspects of such a distributed system in more detail than previous studies. This conference contribution aims at presenting an overview of the DARIS project and at discussing the main results. The project selected extra-galactic surveys and the search for transient radio sources as the best suited science cases within the DARIS concept, and it investigated the scientific and technical requirements for such an array. Several antenna concepts were considered and simulated. An active antenna dipole array concept would be well suited, and a moderate 5 m tip-tip antenna system would lead to a sky noise limited system. Multiple digital signal processing scenarios were considered. Ultimately, although a distributed signal processing approach would be fa-vorable in terms of reliability and scalability, for complexity reasons the project has chosen to have several (5 to 50) identical receiving nodes, and one centralized processing node i.e. the correlator. Analysis has shown that with current technologies, one MHz bandwidth can be processed with full duty cycle. The limiting factor is the inter-satellite link bandwidth. Several deployment locations, such as Moon orbit, Earth-Moon L2, and dynamic Solar orbits were investigated. Each of those locations has its pro's and con's such as interference levels from the Earth (which drive the number of sampling bits), relative speed-vectors of the satellite nodes (influencing maximum correlator integration times, and the need for orbit maintenance), and achievable down-link bandwidth to Earth. Two preferred deployment location were selected: Moon orbit and dynamic Solar orbit. The main advantage of the Moon orbit is that the syn-thetic aperture is filled more rapidly, making it more suitable for transient science than the dynamic Solar orbit. The project also studied the relation between the three-dimensional satellite configuration, the deployment location and the quality of the sky maps. The conclusion is that for the science cases under consideration, sufficient independent aperture sampling points can be obtained in a 1 MHz limited band (with 1 kHz channels) by using bandwidth synthesis. It is expected that, as a result, up to about one million astronomical sources can be detected in a five year duration mission.

Boonstra, Albert-Jan; Saks, Noah; Falcke, Heino; Klein-Wolt, Marc; Bentum, Ark; Thilak Rajan, Raj; Wijnholds, Ir. Stefan J.; Arts, Michel; van-T Klooster, Kees; Belien, Frederik

398

Confocal coded aperture imaging  

DOEpatents

A method for imaging a target volume comprises the steps of: radiating a small bandwidth of energy toward the target volume; focusing the small bandwidth of energy into a beam; moving the target volume through a plurality of positions within the focused beam; collecting a beam of energy scattered from the target volume with a non-diffractive confocal coded aperture; generating a shadow image of said aperture from every point source of radiation in the target volume; and, reconstructing the shadow image into a 3-dimensional image of the every point source by mathematically correlating the shadow image with a digital or analog version of the coded aperture. The method can comprise the step of collecting the beam of energy scattered from the target volume with a Fresnel zone plate.

Tobin, Jr., Kenneth William (Harriman, TN); Thomas, Jr., Clarence E. (Knoxville, TN)

2001-01-01

399

Aperture Photometry Tool  

NASA Astrophysics Data System (ADS)

Aperture Photometry Tool (APT) is software for astronomers and students interested in manually exploring the photometric qualities of astronomical images. It is a graphical user interface (GUI) designed to allow the image data associated with aperture photometry calculations for point and extended sources to be visualized and, therefore, more effectively analyzed. The finely tuned layout of the GUI, along with judicious use of color-coding and alerting, is intended to give maximal user utility and convenience. Simply mouse-clicking on a source in the displayed image will instantly draw a circular or elliptical aperture and sky annulus around the source and will compute the source intensity and its uncertainty, along with several commonly used measures of the local sky background and its variability. The results are displayed and can be optionally saved to an aperture-photometry-table file and plotted on graphs in various ways using functions available in the software. APT is geared toward processing sources in a small number of images and is not suitable for bulk processing a large number of images, unlike other aperture photometry packages (e.g., SExtractor). However, APT does have a convenient source-list tool that enables calculations for a large number of detections in a given image. The source-list tool can be run either in automatic mode to generate an aperture photometry table quickly or in manual mode to permit inspection and adjustment of the calculation for each individual detection. APT displays a variety of useful graphs with just the push of a button, including image histogram, x and y aperture slices, source scatter plot, sky scatter plot, sky histogram, radial profile, curve of growth, and aperture-photometry-table scatter plots and histograms. APT has many functions for customizing the calculations, including outlier rejection, pixel ""picking"" and ""zapping,"" and a selection of source and sky models. The radial-profile-interpolation source model, which is accessed via the radial-profile-plot panel, allows recovery of source intensity from pixels with missing data and can be especially beneficial in crowded fields.

Laher, Russ R.; Gorjian, Varoujan; Rebull, Luisa M.; Masci, Frank J.; Fowler, John W.; Helou, George; Kulkarni, Shrinivas R.; Law, Nicholas M.

2012-07-01

400

Detection of zero anisotropy at 5.2 AU during the November 1998 solar particle event: Ulysses Anisotropy Telescopes observations  

E-print Network

Detection of zero anisotropy at 5.2 AU during the November 1998 solar particle event: Ulysses the Ulysses spacecraft measured constant zero anisotropy of pro- tons in the 1.3±2.2 MeV energy range place at Ulysses between 25 November and 15 December 1998, an event characterised by constant high

Paris-Sud XI, Université de

401

High-Resolution X-Ray Telescopes  

NASA Technical Reports Server (NTRS)

Fundamental needs for future x-ray telescopes: a) Sharp images => excellent angular resolution. b) High throughput => large aperture areas. Generation-X optics technical challenges: a) High resolution => precision mirrors & alignment. b) Large apertures => lots of lightweight mirrors. Innovation needed for technical readiness: a) 4 top-level error terms contribute to image size. b) There are approaches to controlling those errors. Innovation needed for manufacturing readiness. Programmatic issues are comparably challenging.

ODell, Stephen L.; Brissenden, Roger J.; Davis, William; Elsner, Ronald F.; Elvis, Martin; Freeman, Mark; Gaetz, Terry; Gorenstein, Paul; Gubarev, Mikhail V.

2010-01-01

402

Electrostatically clean solar array  

NASA Technical Reports Server (NTRS)

Provided are methods of manufacturing an electrostatically clean solar array panel and the products resulting from the practice of these methods. The preferred method uses an array of solar cells, each with a coverglass where the method includes machining apertures into a flat, electrically conductive sheet so that each aperture is aligned with and undersized with respect to its matched coverglass sheet and thereby fashion a front side shield with apertures (FSA). The undersized portion about each aperture of the bottom side of the FSA shield is bonded to the topside portions nearest the edges of each aperture's matched coverglass. Edge clips are attached to the front side aperture shield edges with the edge clips electrically and mechanically connecting the tops of the coverglasses to the solar panel substrate. The FSA shield, edge clips and substrate edges are bonded so as to produce a conductively grounded electrostatically clean solar array panel.

Stern, Theodore Garry (Inventor); Krumweide, Duane Eric (Inventor)

2004-01-01

403

Design and fabrication of three 1.6-meter telescopes for the Korea Microlensing Telescope Network (KMTNet)  

NASA Astrophysics Data System (ADS)

The KMTNet telescope Project, sponsored by The Korea Astronomy and Space Science Institute (KASI), is fabricating three wide-field equatorial mount telescopes of 1.6 meter aperture to conduct continuous observations of the Galactic bulge region to search for extra-solar planets. Southern latitude sites secured for these telescopes are SAAO (South Africa), CTIO (Chile), and SSO (Australia). A prime-focus configuration, along with a four-lens corrector achieves the 2.8 degree diagonal FOV. The basic mechanical design utilizes a scaled-up version of the successful 2MASS Telescopes built by the authors in the late 1990's. Scaling up of components has presented challenges requiring several iterations of the detailed mechanical analysis as well as the optical analysis due to interaction with mounting assemblies for the optical components. A flexure-style focus mechanism, driven by three precision actuators, moves the entire headring assembly and provides real-time focus capability, and active primary mirror cooling is implemented for the Zerodur primary. KMTNet engineering specifications are met with the current design, which uses Comsoft's Legacy PCTCS for control. A complete operational telescope and enclosure are scheduled for installation in Tucson, AZ prior to shipping the first hardware to CTIO in order to verify tracking, optical characteristics at various attitudes, and overall observatory functionality. The cameras, being fabricated by The Ohio State University Department of Astronomy, Imaging Sciences Laboratory (ISL), are proceeding in parallel with the telescope fabrication, and that interface is now fixed. Specifics of the mechanical and optical design are presented, along with the current fabrication progress and testing protocols.

Poteet, W. M.; Cauthen, H. K.; Kappler, N.; Kappler, L. G.; Park, Byeong-Gon; Lee, Chung-Uk; Kim, Seung-Lee; Cha, Sang-Mok

2012-09-01

404

Space Telescopes  

NASA Technical Reports Server (NTRS)

Space telescopes have been a dominant force in astrophysics and astronomy over the last two decades. As Lyman Spitzer predicted in 1946, space telescopes have opened up much of the electromagnetic spectrum to astronomers, and provided the opportunity to exploit the optical performance of telescopes uncompromised by the turbulent atmosphere. This special section of Optical Engineering is devoted to space telescopes. It focuses on the design and implementation of major space observatories from the gamma-ray to far-infrared, and highlights the scientific and technical breakthroughs enabled by these telescopes. The papers accepted for publication include reviews of major space telescopes spanning the last two decades, in-depth discussions of the design considerations for visible and x-ray telescopes, and papers discussing concepts and technical challenges for future space telescopes.

Clampin, Mark; Flanagan, Kathryn A.

2012-01-01

405

Minimizing high spatial frequency residual in active space telescope mirrors  

E-print Network

The trend in future space telescopes is towards large apertures and lightweight, rib-stiffened, and actively controlled deformable mirrors. These mirror architectures permit the development of segmented and deployed primary ...

Gray, Thomas, S.M. (Thomas L.) Massachusetts Institute of Technology

2008-01-01

406

Wide-field Fizeau imaging telescope: experimental results  

Microsoft Academic Search

A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 murad. The

R. L. Kendrick; Jean-Noel Aubrun; Ray Bell; Robert Benson; Larry Benson; David Brace; John Breakwell; Larry Burriesci; Eric Byler; John Camp; Gene Cross; Peter Cuneo; Peter Dean; Ramji Digumerthi; Alan Duncan; John Farley; Andy Green; Howard H. Hamilton; Bruce Herman; Kris Lauraitis; Erich de Leon; Kenneth Lorell; Rob Martin; Ken Matosian; Tom Muench; Mel Ni; Alice Palmer; Dennis Roseman; Sheldon Russell; Paul Schweiger; Rob Sigler; John Smith; Richard Stone; David Stubbs; Gregg Swietek; John Thatcher; C. Tischhauser; Harvey Wong; Vassilis Zarifis; Kurt Gleichman; Rick Paxman

2006-01-01

407

Synthetic aperture radar interferometry  

Microsoft Academic Search

Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristic of the surface. By exploiting the phase of the coherent radar signal, interferometry has transformed radar remote sensing from a largely interpretive science to a quantitative tool, with applications in cartography, geodesy, land cover

PAUL A. ROSEN; SCOTT HENSLEY; IAN R. JOUGHIN; FUK K. LI; SŘREN N. MADSEN; ERNESTO RODRÍGUEZ; RICHARD M. GOLDSTEIN

2000-01-01

408

Piezoceramic actuated aperture antennae  

Microsoft Academic Search

Recently, it has been demonstrated that aperture antennae can have their performance improved by employing shape control on the antenna surface. The antennae previously studied were actuated utilizing polyvinylidene fluoride (PVDF). Since PVDF is a polymer with limited control authority, these antennae can only be employed in space based applications. This study examines more robust antenna structures devised of a

Hwan-Sik Yoon; Gregory Washington

1998-01-01

409

Piezoceramic actuated aperture antennas  

Microsoft Academic Search

Recently, it has been demonstrated that aperture antennas can have their performance improved by utilizing PVDF as a shape controlling actuator. Since PVDF is a polymer with limited control authority, these antennas can only be employed in space based applications. This study examines more robust antenna structures devised of a thick metalized substrate with surface bonded piezoceramic (PZT) actuators. In

Hwan-Sik Yoon; Gregory Washington

1998-01-01

410

Radio telescopes  

Microsoft Academic Search

A radio telescope is used in radio astronomy to measure the intensity of the radiation received from various parts of the sky. Such a telescope must be able both to detect and to locate faint radio sources of small angular size, and also to measure the brightness distribution across extended radio sources or over large sky areas. Ideally the telescope

J. Findlay

1964-01-01

411

High-contrast Imaging with an Arbitrary Aperture: Active Compensation of Aperture Discontinuities  

NASA Astrophysics Data System (ADS)

We present a new method to achieve high-contrast images using segmented and/or on-axis telescopes. Our approach relies on using two sequential deformable mirrors (DMs) to compensate for the large amplitude excursions in the telescope aperture due to secondary support structures and/or segment gaps. In this configuration the parameter landscape of DM surfaces that yield high-contrast point-spread functions is not linear, and nonlinear methods are needed to find the true minimum in the optimization topology. We solve the highly nonlinear Monge-Ampere equation that is the fundamental equation describing the physics of phase-induced amplitude modulation. We determine the optimum configuration for our two sequential DM system and show that high-throughput and high-contrast solutions can be achieved using realistic surface deformations that are accessible using existing technologies. We name this process Active Compensation of Aperture Discontinuities (ACAD). We show that for geometries similar to the James Webb Space Telescope, ACAD can attain at least 10-7 in contrast and an order of magnitude higher for both the future extremely large telescopes and on-axis architectures reminiscent of the Hubble Space Telescope. We show that the converging nonlinear mappings resulting from our DM shapes actually damp near-field diffraction artifacts in the vicinity of the discontinuities. Thus, ACAD actually lowers the chromatic ringing due to diffraction by segment gaps and struts while not amplifying the diffraction at the aperture edges beyond the Fresnel regime. This outer Fresnel ringing can be mitigated by properly designing the optical system. Consequently, ACAD is a true broadband solution to the problem of high-contrast imaging with segmented and/or on-axis apertures. We finally show that once the nonlinear solution is found, fine tuning with linear methods used in wavefront control can be applied to further contrast by another order of magnitude. Generally speaking, the ACAD technique can be used to significantly improve a broad class of telescope designs for a variety of problems.

Pueyo, Laurent; Norman, Colin

2013-06-01

412

Coronagraph design for an extreme adaptive optics system with spatially filtered wavefront sensing on segmented telescopes  

Microsoft Academic Search

High dynamic range coronagraphy targeted at discovering planets around nearby stars is often associated with monolithic, unobstructed aperture space telescopes. With the advent of extreme adaptive optics (ExAO) systems with thousands of sensing and correcting channels, the benefits of placing a near-infrared coronagraph on a large segmented mirror telescope become scientifically interesting. This is because increased aperture size produces a

Anand Sivaramakrishnan; Russell B. Makidon; Remi Soummer; Bruce A. Macintosh; Mitchell Troy; Gary A. Chanan; James P. Lloyd; Marshall D. Perrin; James R. Graham; Lisa Poyneer; Andrew I. Sheinis

2004-01-01

413

Planetary Remote Sensing Science Enabled by MIDAS (Multiple Instrument Distributed Aperture Sensor)  

NASA Technical Reports Server (NTRS)

The science capabilities and features of an innovative and revolutionary approach to remote sensing imaging systems, aimed at increasing the return on future space science missions many fold, are described. Our concept, called Multiple Instrument Distributed Aperture Sensor (MIDAS), provides a large-aperture, wide-field, diffraction-limited telescope at a fraction of the cost, mass and volume of conventional telescopes, by integrating optical interferometry technologies into a mature multiple aperture array concept that addresses one of the highest needs for advancing future planetary science remote sensing.

Pitman, Joe; Duncan, Alan; Stubbs, David; Sigler, Robert; Kendrick, Rick; Chilese, John; Lipps, Jere; Manga, Mike; Graham, James; dePater, Imke

2004-01-01

414

Looking beyond 30m-class telescopes: the Colossus project  

NASA Astrophysics Data System (ADS)

The exponential growth in exoplanet studies is a powerful reason for developing very large optical systems optimized for narrow-field science. Concepts which cross the boundary between fixed aperture telescopes and interferometers, combined with technologies that decrease the system moving mass, can violate the cost and mass scaling laws that make conventional large-aperture telescopes relatively expensive. Here we describe a concept which breaks this scaling relation in a large optical/IR system called "Colossus"1.

Kuhn, J. R.; Berdyugina, S. V.; Langlois, M.; Moretto, G.; Thiébaut, E.; Harlingten, C.; Halliday, D.

2014-07-01

415

The Falcon Telescope Network  

NASA Astrophysics Data System (ADS)

The Falcon Telescope Network (FTN) is a global network of small aperture telescopes developed by the Center for Space Situational Awareness Research in the Department of Physics at the United States Air Force Academy (USAFA). Consisting of commercially available equipment, the FTN is a collaborative effort between USAFA and other educational institutions ranging from two- and