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1

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

2

Infrared observations of the solar system in support of Large Aperture Infrared Telescope (LARITS): Calibration. Appendices  

NASA Astrophysics Data System (ADS)

An infrared (IR) optics package designed for a IR detector calibration survey will be used in conjunction with the 90 inch telescope at the University of Wyoming, or as a portable, stand along unit. An important part of this instrument package is a mechanical light beam chopper which rotates with a fixed phase relation with respect to a wobbling secondary mirror in the telescope. A control circuit synchronizes the chopper to an external signal when used at the Wyoming site, or generates an internal reference frequency when used as a portable system. The portable system consists of a small equatorial telescope mount to support the same IR instrumentation package, which is used without additional optics. An automated positioning and tracking system encorporates a personal computer to control the environment of the telescope mount via stepper motors attached to the drive axis. The computer is also used to record all data on floppy disc for both fixed and portable systems.

Shorthill, Richard W.

1990-05-01

3

Infrared observations of the solar system in support of Large Aperture Infrared Telescope (LARITS): Calibration  

NASA Astrophysics Data System (ADS)

The purpose of this project was to improve the infrared calibration base for infrared detectors. Groundbased infrared measurements of solid-surfaced planetary bodies, such as asteroids, are being used for the calibration of spacecraft detectors. A limitation has been the relatively poor theoretical understanding of thermal emission from these objects. The goal was to: (1) develop a database of sources, and (2) improve or modify the thermal models for these sources to provide a calibration data base for spacecraft infrared detector systems. The technique consisted of five phases: (1) design and construct infrared detector system to be used with and without collecting optics, (2) acquire whole-disk infrared lunar data relative to a laboratory blackbody and tie them to Mars (Venus or Mercury) and Vega, (3) compare with thermophysical model of the mood and modify, (4) acquire infrared asteroid photometry, and (5) compare the lunar disk photometry the asteroid calibrators using photometry and thermophysical models. The Si bolometer is calibrated without optics, attached to the portable telescope drive and Lunar disk measurement made. Next the bolometer is attached to the 90 inch telescope. Lunar scans are made and the remaining objects (planets, stars, asteroids) are measured.

Shorthill, Richard W.

1990-05-01

4

Aperture synthesis using orbiting telescopes  

NASA Technical Reports Server (NTRS)

A study was carried out to determine the feasibility, with current technology, of performing aperture synthesis using two telescopes orbiting the earth in coordinated orbits separated by approximately 10 m to 1 km. The objective was to determine whether there is a practical alternative to a very large, deployed, servo-controlled submillimeter telescope (i.e., the Large Deployable Reflector) for obtaining high-resolution submillimeter images of astronomical sources. It is found that suitable classes of orbits exist which can provide good UV coverage over the entire sky and the real-time correlation of wideband signals can be performed in orbit using current technology. The most difficult task appears to be the real-time determination of the orientation of the baseline vector in a stable coordinate system. A plausible scheme has been identified for the determination of an arbitrary direction to within 0.003 arcsec in an astrometric coordinate system. This scheme not only makes submillimeter interferometric image reconstruction possible but should also have numerous other applications.

Kuiper, T. B. H.; Synnott, S. P.; Linfield, R. P.; Resch, G. M.; Tubbs, E. F.

1985-01-01

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

Optical aperture synthesis with electronically connected telescopes  

E-print Network

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

Dainis Dravins; Tiphaine Lagadec; Paul D. Nuñez

2015-04-17

7

Optical aperture synthesis with electronically connected telescopes.  

PubMed

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

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

2015-01-01

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

Technology demonstration solar telescope  

Microsoft Academic Search

The conceptual design of the Large Earth-based Solar Telescope (LEST) has evolved through the years. In 1995-97 it was discussed whether a technology demonstration telescope could be built at a lower cost than the LEST originally proposed. In 1997, a de-scoped LEST design, the so-called \\

Torben Andersen; Oddbjrn Engvold; Mette Owner-Pedersen

2002-01-01

10

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

11

Solar Central Receiver with an Irising Aperture  

E-print Network

. If the aperture is small, it will be inefficient for periods when the solar isolation is inclined due to spillage. However, if the aperture is large, it will be inefficient for periods when the solar isolation is normal, due to excess heat radiation and convection...

Galal, T.; Kulaib, A. M.; Abuzaid, M.

2010-01-01

12

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

E-print Network

Abstract The segmented mirror and deployable optics technologies developed for the James Webb Space Telescope enable a 6A 16-m Telescope for the Advanced Technology Large Aperture Telescope (ATLAST) Mission Charles F Study Team Mission Concept Our ATLAST 16-meter telescope Mission Concept will utilize the capabilities

Sirianni, Marco

13

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

14

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

15

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

16

Conceptual design of a compact optical synthetic aperture telescope  

NASA Astrophysics Data System (ADS)

Y-4 synthetic aperture telescope consists of four 40cm sub-telescopes that are configured as Y-type array based on an unique AZ-Alt mounting. After passing through every sub-aperture, star lights are transformed into parallel beams, enter relay optics for co-phasing sensing, finally combined by an optical combiner and form interferometric images in image plane. Because all tubes are installed on single mounting, the complicate outer optical delay line can be avoided. Y-4 array telescope is of some advantages such as efficient diameter, angle resolution with respect to some other configurations. Some negative influence of beam combining errors including piston, tip/tilt, and pupil mapping error aiming to Y-4 array is analyzed subsequently. The preliminary mechanical and optics design of Y-4 telescope is introduced respectively.

Zhu, Neng-hong Zhu; Chen, Xin-yang, Zhou, Dan; Zhang, Cong-cong; Zheng, Li-xin; Wang, Chao-yan

2014-04-01

17

The Five-Hundred Aperture Spherical Radio Telescope (fast) Project  

Microsoft Academic Search

Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. Its innovative engineering concept and design pave a new road to realize a huge single dish in the most effective way. FAST also represents Chinese contribution in the international efforts to build the square kilometer array (SKA). Being

Rendong Nan; Di Li; Chengjin Jin; Qiming Wang; Lichun Zhu; Wenbai Zhu; Haiyan Zhang; Youling Yue; Lei Qian

2011-01-01

18

ADVANCED TECHNOLOGY LARGE-APERTURE SPACE TELESCOPE (ATLAST)  

E-print Network

= Northrop Grumman Aerospace Systems 8 = Jet Propulsion Laboratory, California Institute of Technology 9ADVANCED TECHNOLOGY LARGE-APERTURE SPACE TELESCOPE (ATLAST): A TECHNOLOGY ROADMAP FOR THE NEXT Aerospace & Technologies Corp. 2 = Marshall Space Flight Center 3 = Goddard Space Flight Center 4 = Space

Sirianni, Marco

19

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

20

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

21

Strategies for servicing the Single Aperture Far IR (SAFIR) telescope  

NASA Astrophysics Data System (ADS)

The Single Aperture Far Infrared (SAFIR) observatory is a high priority mission for NASA and space astronomy. This ten-meter diameter telescope, operating at <10 Kelvin, will chart the formation of galaxies and elements in the early universe, map debris disks around stars to track hidden planets, and explore the chemistry of life in the universe. While baselined as an autonomously deployed telescope, we consider enabling factors that in-space operations would bring to this telescope - in particular, servicing opportunities that would dramatically increase the scientific lifetime and productivity of the observatory. The use of humans and robots to support and conduct servicing, at the operational site of Earth-Sun L2 and primarily at Earth-Moon L1, are considered, and the required capabilities are reviewed. SAFIR shares many characteristics of future large telescopes in space, and strategies developed for this strawman case are applicable for broader planning efforts.

Lester, Dan; Friedman, Ed; Lillie, Charles

2005-08-01

22

Misalignment Sensing for Optical Aperture Synthesis Telescope Using Phase Diversity  

NASA Astrophysics Data System (ADS)

An optical aperture synthesis telescope such as the Multi-Mirror Telescope will suffer from phase errors unless the segments are aligned to within a small fraction of a wavelength. As an optical misalignment sensing technique, phase diversity can estimate the pupil phase from pairs of simultaneously recorded focused and defocused images, then the misalignment error is obtained. The image-forming system has been simulated by computer, and the unknown wavefront has been estimated by using the method of finite differences. Simulation results show phase-diversity method can accurately retrieve the wavefront, and sense misalignment error.

Cao, Fang; Wu, Zhen; Zhu, Yong-Tian

2008-09-01

23

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

24

Adaptive Optics for the 8 meter Chinese Giant Solar Telescope  

NASA Astrophysics Data System (ADS)

Solar ELTs enable diffraction limited imaging of the basic structure of the solar atmosphere. Magneto-hydrodynamic considerations limit their size to about 0.03 arcsec. To observe them in the near-infrared 8-meter class telescopes are needed. The Chinese Giant Solar Telescope, or CGST, is such a NIR solar ELT. It is a Ring Telescope with 8-meter outer diameter and a central clear aperture of about 6-meter diameter. At present various options for such a Gregorian type telescope are under study like a continuous ring made of segments or a multiple aperture ring made of 7 off-axis telescopes. The advantages of such a ring telescope is that its MTF covers all spatial frequencies out to those corresponding to its outer diameter, that its circular symmetry makes it polarization neutral, and that its large central hole helps thermal control and provides ample space for MCAO and Gregorian instrumentation. We present the current status of the design of the CGST. Our thinking is guided by the outstanding performance of the 1-meter vacuum solar telescope of the Yunnan Solar Observatory which like the CGST uses both AO and image reconstruction. Using it with a ring-shape aperture mask the imaging techniques for the CGST are being explored. The CGST will have Multi-Conjugate Adaptive Optics (MCAO). The peculiarities of Atmospheric Wavefront Tomography for Ring Telescopes are aided by the ample availability of guide stars on the Sun. IR MCAO-aided diffraction limited imaging offers the advantage of a large FOV, and high solar magnetic field sensitivity. Site testing is proceeding in western China, (e.g. northern Yunnan Province and Tibet). The CGST is a Chinese solar community project originated by the Yunnan Astronomical Observatory, the National Astronomical Observatories, the Purple Mountain Observatory, the Nanjing University, the Nanjing Institute of Astronomical Optics & Technology and the Beijing Normal University.

Beckers, Jacques; Liu, Zhong; Deng, Yuanyong; Ji, Haisheng

2013-12-01

25

CASTEL: Capodimonte Antarctic Solar TELescope  

NASA Astrophysics Data System (ADS)

The program of the CONCORDIASTRO/Italy project consists of the installation of a 40 cm telescope at Dome C. This telescope will be used to acquire time-series of filtergrams in the visible at both medium and high spatial resolution, with the aim to qualify Dome C for solar observations. In case the expectation of very good seeing at Dome C will be confirmed, this site will allow long-lasting, high spatial resolution data that are needed for many scientific purposes; one example, of interest for our group, is the study of small seismic events that are considered the best candidate to excite the solar global oscillations. This contribution focuses on the project planning of CONCORDIASTRO/Italy and on the telescope named CASTEL (Capodimonte (or Concordia) Antarctic Solar TELescope).

Moretti, P. F.; Severino, G.

26

Active Optics for a 16-Meter Advanced Technology Large Aperture Space Telescope  

E-print Network

preliminary architecture builds on technologies from the James Webb Space Telescope (JWST), the SpaceActive Optics for a 16-Meter Advanced Technology Large Aperture Space Telescope David C. Redding-optics Advanced Technology Large Aperture Space Telescope, to be launched by the Ares V Heavy Lift Vehicle

Sirianni, Marco

27

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

28

The New Solar Telescope (NST): What’s Next ?  

NASA Astrophysics Data System (ADS)

The 1.6 m, off-axis, clear aperture New Solar Telescope (NST) has been in regular operation in Big Bear Solar Observatory since 2009. The NST is the first facility class solar telescope built in the U.S. in a generation, which already offers a significant improvement in ground-based high angular resolution capabilities. This presentation reports the up-to-date progress on the NST and its 2nd generation instruments including the AO system (AO-308), the Near-InfraRed Imaging Spectro-polarimeter (NIRIS), the Visible Imaging Spectrometer (VIS), and the Cryogenic Infrared Spectrograph (CYRA).

Cao, Wenda; Goode, P. R.; NST Team

2013-07-01

29

The COronal Solar Magnetism Observatory (COSMO) Large Aperture Coronagraph  

NASA Astrophysics Data System (ADS)

The COSMO is a facility dedicated to observing coronal and chromospheric magnetic fields. It will be located on a mountaintop in the Hawaiian Islands and will replace the current Mauna Loa Solar Observatory (MLSO). COSMO will provide unique observations of the global coronal magnetic fields and its environment to enhance the value of data collected by other observatories on the ground (e.g. SOLIS, BBO NST, Gregor, ATST, EST, Chinese Giant Solar Telescope, NLST, FASR) and in space (e.g. SDO, Hinode, SOHO, GOES, STEREO, Solar-C, Solar Probe+, Solar Orbiter). COSMO will employ a fleet of instruments to cover many aspects of measuring magnetic fields in the solar atmosphere. The dynamics and energy flow in the corona are dominated by magnetic fields. To understand the formation of CMEs, their relation to other forms of solar activity, and their progression out into the solar wind requires measurements of coronal magnetic fields. The large aperture coronagraph, the Chromospheric and Prominence Magnetometer and the K-Coronagraph form the COSMO instrument suite to measure magnetic fields and the polarization brightness of the low corona used to infer electron density. The large aperture coronagraph will employ a 1.5 meter fuse silica singlet lens, birefringent filters, and a spectropolarimeter to cover fields of view of up to 1 degree. It will observe the corona over a wide range of emission lines from 530.3 nm through 1083.0 nm allowing for magnetic field measurements over a wide range of coronal temperatures (e.g. FeXIV at 530.3 nm, Fe X at 637.4 nm, Fe XIII at 1074.7 and 1079.8 nm. These lines are faint and require the very large aperture. NCAR and NSF have provided funding to bring the large aperture coronagraph to a preliminary design review state by the end of 2013. As with all data from Mauna Loa, the data products from COSMO will be available to the community via the Mauna Loa website: http://mlso.hao.ucar.edu

Tomczyk, Steve; Gallagher, Dennis; Wu, Zhen; Zhang, Haiying; Nelson, Pete; Burkepile, Joan; Kolinksi, Don; Sutherland, Lee

2013-04-01

30

The Five-Hundred Aperture Spherical Radio Telescope (fast) Project  

NASA Astrophysics Data System (ADS)

Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. Its innovative engineering concept and design pave a new road to realize a huge single dish in the most effective way. FAST also represents Chinese contribution in the international efforts to build the square kilometer array (SKA). Being the most sensitive single dish radio telescope, FAST will enable astronomers to jump-start many science goals, such as surveying the neutral hydrogen in the Milky Way and other galaxies, detecting faint pulsars, looking for the first shining stars, hearing the possible signals from other civilizations, etc. The idea of sitting a large spherical dish in a karst depression is rooted in Arecibo telescope. FAST is an Arecibo-type antenna with three outstanding aspects: the karst depression used as the site, which is large to host the 500-meter telescope and deep to allow a zenith angle of 40 degrees; the active main reflector correcting for spherical aberration on the ground to achieve a full polarization and a wide band without involving complex feed systems; and the light-weight feed cabin driven by cables and servomechanism plus a parallel robot as a secondary adjustable system to move with high precision. The feasibility studies for FAST have been carried out for 14 years, supported by Chinese and world astronomical communities. Funding for FAST has been approved by the National Development and Reform Commission in July of 2007 with a capital budget ~ 700 million RMB. The project time is 5.5 years from the commencement of work in March of 2011 and the first light is expected to be in 2016. This review intends to introduce the project of FAST with emphasis on the recent progress since 2006. In this paper, the subsystems of FAST are described in modest details followed by discussions of the fundamental science goals and examples of early science projects.

Nan, Rendong; Li, Di; Jin, Chengjin; Wang, Qiming; Zhu, Lichun; Zhu, Wenbai; Zhang, Haiyan; Yue, Youling; Qian, Lei

31

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

2008-03-27

32

EST: The European Solar Telescope  

NASA Astrophysics Data System (ADS)

The European Solar Telescope (EST) is a project for a 4 meter-class ground-based telescope, to be located in the Canary Islands. The project is promoted by the European Association for Solar Telescopes (EAST), a consortium formed by research organizations from 15 European countries. EST will be optimized for studies of magnetic coupling between the deep photosphere and upper chromosphere. The project has been approved for funds by the European Union, within the FP-7 framework, to produce the design of all systems and subsystems of the telescope during the next three years. This includes the optical and optomechanical design of the telescope itself and of the instruments and their control. MCAO will be included in the optical path in a natural way to compensate for atmospheric disturbances in an optimum way. The design of EST will strongly emphasize the use of a large number of visible and near-infrared instruments simultaneously which will influence the telescope design from the very beginning. This communication will center mainly on the scientific objectives that EST will address. Generally speaking, they involve understanding how the magnetic field emerges through the solar surface, interacts with the plasma dynamics to transfer energy between different regions, and finally releases it in the form of heat or as violent events in the solar chromosphere and corona. Among the many topics of interest, one may cite, as described in the EST Science Requirements Document: small-scale flux emergence in quiet sun regions, large-scale magnetic structures, magnetic flux cancellation processes, polar magnetic fields, magnetic topology of the photosphere and chromosphere, conversion of mechanical to magnetic energy in the photosphere, wave propagation from photosphere to chromosphere, energy dissipation in the chromosphere at small and large scales, etc. The present status and future perspectives of the project will also be outlined.

Collados, M.

2008-09-01

33

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

34

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

35

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

36

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

37

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

38

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

E-print Network

, Nicolas Gorceixb, Roy Coulterb, Aaron Coulterb, Philip R. Goodeab aCenter for Solar-Terrestrial Research Observatory. The NST will be the largest aperture solar telescope in the world until the 4 m Advanced activity and variability. To verify and guide modeling of magneto-convection and flux emergence, transport

39

A large single-aperture telescope for submillimeter astronomy  

Microsoft Academic Search

The large submillimeter telescope (LST) is a proposed wide-field, 30m-class telescope operating from a ground-based site in the relatively unexplored 0.2 - 1mm waveband. The telescope will be equipped with imaging and spectroscopic instrumentation to allow astronomers to probe the earliest evolutionary stages of galaxies, stars and planets. It is intended to operate the telescope in the 200mum atmospheric window,

Wayne Holland; Rob Ivison; William Dent; Eli Atad; Ian Robson; Andy Longmore; Tim Hawarden; Jane Greaves; James Dunlop; Derek Ward-Thompson; Wolfgang Wild

2006-01-01

40

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

41

Optical design and testing of a fast large-aperture infrared space telescope  

Microsoft Academic Search

An optical design study for a next generation infrared space telescope has been performed. The concept is that of a passively cooled telescope of minimum aperture 2.5 meter with an F\\/1.2 primary and wavelength coverage from (lambda) equals 2 to at least 40 micrometers , and possibly to 100 micrometers . Compactness, low thermal emission from the optics and structure,

Colin M. Humphries; Yitzhak Nevo; Eli Ettedgui-Atad; John W. Harris

1992-01-01

42

Optical design and testing of a fast, large aperture, infrared space telescope  

Microsoft Academic Search

An optical design study for a next generation infrared space telescope has been performed. The concept is that of a passively cooled telescope of minium aperture 2.5 metre with an F\\/1.2 primary and wavelength coverage from ? = 2 to at least 40 µm, and possibly to 100 µm. Compactness, low thermal emission from the optics and structure, diffraction limited

C. M. Humphries; Y. Nevo; E. Ettedgui-Atad; J. W. Harris

1992-01-01

43

Experimental demonstration of a self-tracking 16aperture receiver telescope array for laser intersatellite communications  

Microsoft Academic Search

An adaptive receive telescope array with 16 apertures has been designed and breadboarded. With respect to size and performance, such a telescope array is well suited for use as receive antenna in a coherent interorbit laser link. The laboratory demonstrator, designed to operate at a wavelength of (lambda) equals 1.064 micrometers, is completely independent of any subsequent receiver and of

Andras Kalmar; Klaus H. Kudielka; Walter R. Leeb

1998-01-01

44

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

45

Effects of Misalignment Errors on the Optical Transfer Functions of Synthetic Aperture Telescopes  

NASA Astrophysics Data System (ADS)

A segmented or diluted aperture optical system will undergo phase errors as a result of errors in the positioning of the segments. The errors associated with a segmented primary mirror limit the image quality obtainable with synthetic aperture telescopes. Here we study the effects of segmentation errors on image quality, considering both the phase angle and the amplitude of the optical transfer function (OTF). We show that, in these kinds of telescope, phasing and alignment errors among segments reduce the amplitude and distort the phase angle of the OTF.

Flores, Jorge L.; Strojnik, Marija; Páez, Gonzalo; García-Torales, Guillermo

2004-11-01

46

Effect of misalignment errors on the optical transfer function of the synthetic aperture telescopes  

NASA Astrophysics Data System (ADS)

A segmented or diluted aperture optical system will undergo phase errors due to errors in the positing of the segments. The errors associated with a segmented primary mirror limit the image quality obtainable with the synthetic aperture telescopes. Here, we study the effects of segmentation errors on image quality considering both the phase angle and amplitude of the OTF. We show that, in these kind telescopes, the phasing and alignment errors among segments reduce the amplitude and distort the phase angle of the OTF.

Flores, Jorge L.; Paez, Gonzalo; Strojnik, Marija; Garcia, Guillermo

2003-12-01

47

The application of wavefront coding technology to a large segmented synthetic aperture telescope  

NASA Astrophysics Data System (ADS)

The utilization of a telescope with a large single aperture is limited by the manufacturing technique, cost, volume and weight of a monolithic mirror. In order to solve these problems, the technology of the segmented synthetic aperture was introduced. The primary mirror of a large segmented synthetic aperture telescope consists of several segmented mirrors, whose misalignment errors make the wavefront change drastically and influence the MTF of the optical system badly. The wavefront coding technology (WFC) is an innovative technology that joints the optical design and digital image processing together. By adding a phase mask close to the pupil of an optical system and modulating the wavefront, the WFC system becomes very insensitive to defocus and other aberrations based on defocus. The theoretical analysis of characteristics of the WFC system was done in the form of PSF. The application of WFC to a segmented three mirror anastigmat (TMA) was presented. A space telescope with an effective focal length as 40m, a F number as 10, a field of view as 0.5°x0.05° was designed, whose primary mirror consisted of seven segmented mirrors. The influence of defocus and misalignment errors on the telescope was discussed. The imaging process of the WFC system and following image restoration were simulated. As a result, sharp images were obtained and the large segmented synthetic aperture telescope had looser misalignment tolerance and extended depth of focus.

Feng, Litong; Meng, Junhe; Dun, Xiong; Tao, Yu; Zhu, Lixin; Wu, Xiaojing; Zhang, Zhen; Zhang, Chenzhong; Chen, Xin; Lei, Li; Zhao, Kan

2010-05-01

48

Optical design and testing of a fast, large aperture, infrared space telescope  

Microsoft Academic Search

An optical design study for a next generation infrared space telescope has been performed. The concept is that of a passively cooled telescope of minimum aperture 2.5 m with an F\\/1.2 primary and wavelength coverage from 2 to as least 40 microns, and possibly to 100 microns. Compactness, low thermal emission from the optics and structure, diffraction limited imaging at

C. M. Humphries; Y. Nevo; E. Ettedgui-Atad; J. W. Harris

1992-01-01

49

FAST - Five hundred meter Aperture Spherical radio Telescope  

Microsoft Academic Search

The idea of sitting a large spherical dish in Karst depression is rooted in Arecibo telescope hosted by the NAIC of Cornell University. FAST is an Arecibo-type antenna with 3 outstanding aspects: the unique karst depression as the site; the active main reflector which corrects spherical aberration on the ground to achieve full polarization and wide band without involving complex

Ren-Dong Nan

2009-01-01

50

Performance predictions for spaceborne, long-lifetime helium dewars containing large-aperture telescopes  

NASA Technical Reports Server (NTRS)

The evolution of design approaches for high-performance superfluid helium dewars containing large-aperture telescopes are discussed. Particular attention is given to thermal-math modeling for the IRAS and the Cosmic Background Explorer (COBE) dewars. Correlation of the recent COBE flight data with the dewar thermal-math model is presented, and apparent predictive deficiencies of the model are discussed.

Hopkins, Richard A.; Nieczkoski, Stephen J.; Volz, Stephen M.

1990-01-01

51

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

52

ATLAST-9.2: A Deployable Large Aperture UVOIR Space Telescope  

Microsoft Academic Search

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

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

2010-01-01

53

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

E-print Network

' The Revolution in Telescope Aperture C.M. Mountain and F.C. Gillett Gemini Observatory, 670 N. A of the Kitt Peak National Observatory have seen several revolutions in astronomy. One such revolution. This revolution, although ultimately driven by curiosity, has come about because of advances in computers

54

Atmospheric-induced wavefront distortion and compensation on large-aperture millimeter-wave telescopes  

Microsoft Academic Search

In the troposphere water vapor plays a fundamental role in radio propagation. The refractivity of water vapor is about 20 times greater in the radio range than in near-infrared or optical regimes. As a consequence, phase fluctuations at frequencies higher than about 1 GHz are predominantly caused by fluctuations in the distribution of water vapor. On filled-aperture telescopes radio seeing

Luca Olmi

2003-01-01

55

GREGOR, a 1.5 M Solar Telescope  

NASA Astrophysics Data System (ADS)

We present the design of a new large solar telescope which is going to be installed at the Observatorio del Teide, in the tower that presently houses the 45cm Gregory-Coudé-Telescope. The new telescope has an aperture of 1.5 meters and its optical design is basically a Gregorian configuration. It will be an open telescope in an azimuthal mount. An adaptive optics system is incorporated in the optical design as well as a polarimetry package. The feasibility of lightweight optics for the primary mirror has been investigated in an industrial pre-study. The focal plane instrumentation will include a high resolution filter spectrometer similar to the existing TESOS instrument at the VTT and a new spectro-polarimeter for the visible and the near UV. The latter instrument is presently being developed jointly by the KIS and the High Altitude Observatory in Boulder, USA. Budget permitting, detailed (Phase-B) planning will start in 2000, and the telescope will be developed and built in 2002 and 2003 with first light in spring of 2004.

von der Lühe, O.; Schmidt, W.; Soltau, D.; Kneer, F.; Staude, J.

56

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

57

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

58

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

59

Heterodyne Doppler 1-micron lidar measurement of reduced effective telescope aperture due to atmospheric turbulence  

NASA Astrophysics Data System (ADS)

A pulsed Nd:YAG bistatic focused-beam lidar allowing simultaneous heterodyne and direct detection of the same lidar returns has been experimentally employed to ascertain the effect of atmospheric turbulence on heterodyne and direct-detection lidar at 1 micron, by measuring the average carrier-to-noise ratio and statistical fluctuation level in the return signals under various experimental and atmospheric conditions. Atmospheric turbulence is found capable of reducing the lidar receiver's effective telescope aperture and heterodyne detection efficiency. This observed effective-aperture limitation functionally resembles predictions based on the Clifford and Wandzura (1981) heterodyne wavefront detection theory.

Chan, Kin Pui; Killinger, Dennis K.; Sugimoto, Nobuo

1991-06-01

60

FAST - Five hundred meter Aperture Spherical radio Telescope  

NASA Astrophysics Data System (ADS)

The idea of sitting a large spherical dish in Karst depression is rooted in Arecibo telescope hosted by the NAIC of Cornell University. FAST is an Arecibo-type antenna with 3 outstanding aspects: the unique karst depression as the site; the active main reflector which corrects spherical aberration on the ground to achieve full polarization and wide band without involving complex feed system; and the light focus cabin driven by cables and servomechanism plus a parallel robot as secondary adjustable system to carry the most precise parts of the receivers. These design features will enable FAST to jumpstart many of science goals, such as HI neutral hydrogen line survey, pulsar survey, largest station in VLBI network, spectral line observations and Search for alien's technologies. The feasibility studies for FAST have been carried out for 14 years, being supported by Chinese and world astronomical communities. Funding for Project FAST has been approved by the National Development and Reform commission NDRC in July of 2007 with a capital budget 600 millions RMB and a project time of 5.5 years from the foundation. The first light is expected to be in early 2014. This work is supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China (Grant No. 10433020). More than a hundred research personnel from over thirty research teams were involved in this research. On behalf of project FAST, I wish to make special recognition to their diligent work and great contribution to the project.

Nan, Ren-Dong

2009-01-01

61

Advanced Technology Large-Aperture Space Telescope (ATLAST) Appendix G: ATLAST-9.2m Design Study  

E-print Network

) are required to achieve the ATLAST-9.2m requirements. ATLAST-9.2m draws heavily on James Webb Space TelescopeAdvanced Technology Large-Aperture Space Telescope (ATLAST) 1 Appendix G: ATLAST-9.2m Design Study.........................................................................8 G 2.1 ATLAST 9.2m Optical Telescope Assembly

Sirianni, Marco

62

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

63

The CERN Axion Solar Telescope  

Microsoft Academic Search

The CAST experiment at CERN is using a decommissioned LHC prototype magnet to search for solar axions through their Primakoff conversion into x-ray photons. The magnet (B = 9.0 Tesla, L = 10 m) can track the sun each day for a total exposure time of ~180 minutes (sunrise + sunset). We expect to reach a sensitivity in axion-photon coupling,

M. D. Hasinoff; S. Andriamonje; E. Arik; D. Autiero; F. Avignone; K. Barth; E. Bingol; H. Brauninger; R. Brodzinski; J. Carmona; E. Chesi; S. Cebrian; S. Cetin; J. Collar; R. Creswick; T. Dafni; R. de Oliveira; S. Dedoussis; A. Delbart; L. di Lella; C. Eleftheriadis; G. Fanourakis; H. Farach; H. Fischer; F. Formenti; T. Geralis; I. Giomataris; S. Gninenko; N. Goloubev; R. Hartmann; D. Hoffmann; I. G. Irastorza; J. Jacoby; D. Kang; K. Konigsmann; R. Kotthaus; M. Krcmar; M. Kuster; B. Lakic; A. Liolios; A. Ljubicic; G. Lutz; G. Luzon; H. Miley; A. Morales; J. Morales; M. Mutterer; A. Nikolaidis; A. Ortiz; T. Papaevangelou; A. Placci; G. Raffelt; H. Riege; M. Sarsa; I. Savvidis; R. Schopper; I. Semertzidis; C. Spano; J. Villar; B. Vullierme; L. Walckiers; K. Zachariadou; K. Zioutas

2003-01-01

64

Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements  

NASA Technical Reports Server (NTRS)

An advanced large aperture UV/optical UVO space telescope is required for the next generation of astrophysics and exoplanet science. The science requirements of proposed exoplanet and astrophysics missions were used to determine the encircled energy, point spread function stability and thermal environment requirements. These requirements then determine the optical wavefront specification for potential telescope assemblies which can fit inside current and planned launch vehicles. The optical wavefront specification becomes the top level of the error budget that is split into various sources that control the structural, thermal and optical design.

Stahl, H. Philip; Arnold, William; Bevan, Ryan M.; Smith, W. Scott.; Kirk, Charles S.; Postman, Mark

2013-01-01

65

High-contrast imager for complex aperture telescopes (HiCAT): 1. testbed design  

NASA Astrophysics Data System (ADS)

Searching for nearby habitable worlds with direct imaging and spectroscopy will require a telescope large enough to provide angular resolution and sensitivity to planets around a significant sample of stars. Segmented telescopes are a compelling option to obtain such large apertures. However, these telescope designs have a complex geometry (central obstruction, support structures, segmentation) that makes high-contrast imaging more challenging. We are developing a new high-contrast imaging testbed at STScI to provide an integrated solution for wavefront control and starlight suppression on complex aperture geometries. We present our approach for the testbed optical design, which defines the surface requirements for each mirror to minimize the amplitude-induced errors from the propagation of out-of-pupil surfaces. Our approach guarantees that the testbed will not be limited by these Fresnel propagation effects, but only by the aperture geometry. This approach involves iterations between classical ray-tracing optical design optimization, and end-to-end Fresnel propagation with wavefront control (e.g. Electric Field Conjugation / Stroke Minimization). The construction of the testbed is planned to start in late Fall 2013.

N'Diaye, Mamadou; Choquet, Elodie; Pueyo, Laurent; Elliot, Erin; Perrin, Marshall D.; Wallace, J. Kent; Groff, Tyler; Carlotti, Alexis; Mawet, Dimitri; Sheckells, Matt; Shaklan, Stuart; Macintosh, Bruce; Kasdin, N. Jeremy; Soummer, Rémi

2013-09-01

66

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

67

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

68

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

E-print Network

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 thus to compare with specifications. In this work 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 validit...

Olmi, Luca

2007-01-01

69

The five-hundred-meter aperture spherical radio telescope (FAST) project  

NASA Astrophysics Data System (ADS)

Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese "mega-science" project to build the largest single dish radio telescope in the world. Its engineering concept and design pave a new road to realize a huge single dish in an effective way. Being the most sensitive single dish radio telescope, FAST will enable astronomers to jump-start many science goals, such as surveying the neutral hydrogen in the Milky Way and other galaxies, detecting faint pulsars, hearing the possible signals from other civilizations, etc. The feasibility studies for FAST have been carried out for 14 years, supported by Chinese and international astronomy communities. The National Development and Reform Commission approved the funding proposal of FAST in 2007 with a capital budget close to 700 million RMB. The project time is 5.5 years from the commencement of work in March of 2011 and the first light is expected in 2016.

Nan, Rendong; Li, Di

2013-04-01

70

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

71

Hubble Space Telescope (HST) Solar Array Damper  

NASA Technical Reports Server (NTRS)

This paper describes the design of a solar array damper that will be built into each of two new solar arrays to be installed on the Hubble Space Telescope (HST) during Servicing Mission 3. On this mission, currently scheduled for August, 2000, two "rigid" solar array wings will replace the "flexible" wings currently providing power for HST. Dynamic interaction of these wings with the telescope spacecraft can affect the Pointing Control System. The damper, which is integral to the mast of the solar array, suppresses the fundamental bending modes of the deployed wings at 1.2 Hz (in-plane) and 1.6 Hz (out-of-plane). With the flight version of the damper, modal damping of 2.3% of critical is expected over the temperature range of -4 C to 23 C with a peak damping level of 3.9%. The unique damper design is a combination of a titanium spring and viscoelastic-shear-lap dashpot. The damper was designed using a system finite element model of the solar array wing and measured viscoelastic material properties. Direct complex stiffness (DCS) testing was performed to characterize the frequency- and temperature-dependent behavior of the damping prior to fixed-base modal testing of the wing at NASA/Goddard Space Flight Center (NASA/GSFC).

Maly, J. R.; Pendleton, S. C.; Salmanoff, J.; Blount, G. J.; Mathews, K.

1999-01-01

72

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

73

High-contrast imager for Complex Aperture Telescopes (HiCAT): testbed design and coronagraph developments  

NASA Astrophysics Data System (ADS)

We present a new high-contrast imaging testbed designed to provide complete solutions for wavefront sensing and control and starlight suppression with complex aperture telescopes (NASA APRA; Soummer PI). This includes geometries with central obstruction, support structures, and/or primary mirror segmentation. Complex aperture telescopes are often associated with large telescope designs, which are considered for future space missions. However, these designs makes high-contrast imaging challenging because of additional diffraction features in the point spread function. We present a novel optimization approach for the testbed optical and opto-mechanical design that minimizes the impact of both phase and amplitude errors from the wave propagation of testbed optics surface errors. This design approach allows us to define the specification for the bench optics, which we then compare to the manufactured parts. We discuss the testbed alignment and first results. We also present our coronagraph design for different testbed pupil shapes (AFTA or ATLAST), which involves a new method for the optimization of Apodized Pupil Lyot Coronagraphs (APLC).

N'Diaye, Mamadou; Choquet, E.; Pueyo, L.; Elliot, E.; Perrin, M. D.; Wallace, J.; Anderson, R. E.; Carlotti, A.; Groff, T. D.; Hartig, G. F.; Kasdin, J.; Lajoie, C.; Levecq, O.; Long, C.; Macintosh, B.; Mawet, D.; Norman, C. A.; Shaklan, S.; Sheckells, M.; Sivaramakrishnan, A.; Soummer, R.

2014-01-01

74

High-contrast Imager for Complex Aperture Telescopes (HICAT): II. Design overview and first light results  

NASA Astrophysics Data System (ADS)

We present a new high-contrast imaging testbed designed to provide complete solutions in wavefront sensing, control and starlight suppression with complex aperture telescopes. The testbed was designed to enable a wide range of studies of the effects of such telescope geometries, with primary mirror segmentation, central obstruction, and spiders. The associated diffraction features in the point spread function make high-contrast imaging more challenging. In particular the testbed will be compatible with both AFTA-like and ATLAST-like aperture shapes, respectively on-axis monolithic, and on-axis segmented telescopes. The testbed optical design was developed using a novel approach to define the layout and surface error requirements to minimize amplitude­ induced errors at the target contrast level performance. In this communication we compare the as-built surface errors for each optic to their specifications based on end-to-end Fresnel modelling of the testbed. We also report on the testbed optical and optomechanical alignment performance, coronagraph design and manufacturing, and preliminary first light results.

N'Diaye, Mamadou; Choquet, Elodie; Egron, Sylvain; Pueyo, Laurent; Leboulleux, Lucie; Levecq, Olivier; Perrin, Marshall D.; Elliot, Erin; Wallace, J. Kent; Hugot, Emmanuel; Marcos, Michel; Ferrari, Marc; Long, Chris A.; Anderson, Rachel; DiFelice, Audrey; Soummer, Rémi

2014-08-01

75

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

76

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

77

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

NASA Astrophysics Data System (ADS)

The close-pack array of the MROI necessitated an original design for the Unit Telescope Enclosure (UTE) at Magdalena Ridge Observatory. The Magdalena Ridge Observatory Interferometer (MROI) is a project which comprises an array of up to ten (10) 1.4m diameter mirror telescopes arranged in a "Y" configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. The most compact configuration includes all ten telescopes, several of which are at a relative distance of less than 8m center to center from each other. Since the minimum angle of the field of regard is 30° with respect to the horizon, it is difficult to prevent optical blockage caused by adjacent UTEs in this compact array. This paper presents the design constraints inherent in meeting the requirement for the close-pack array. An innovative design enclosure was created which incorporates an unique dome/observing aperture system. The description of this system focuses on how the field of regard requirement led to an unique and highly innovative concept that had to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). Finally, we describe the wide use of composites materials and structures (e.g. glass/carbon fibres, sandwich panels etc.) on the aperture system which represents the only way to guarantee adequate thermal and environmental protection, compactness, structural stability and limited power consumption due to reduced mass.

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

2010-07-01

78

ExSPO: A Discovery Class Apodized Square Aperture (ASA) Expo-Planet Imaging Space Telescope Concept  

NASA Technical Reports Server (NTRS)

ExSPO is a Discovery Class (approx. 4 meter) apodized square aperture (ASA) space telescope mission designed for direct imaging of extrasolar Earth-like planets, as a precursor to TPF. The ASA telescope concept, instrument design, capabilities, mission plan and science goals are described.

Gezari, D.; Harwit, M.; Lyon, R.; Melnick, G.; Papaliolos, G.; Ridgeway, S.; Woodruff, R.; Nisenson, P.; Oegerle, William (Technical Monitor)

2002-01-01

79

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

NASA Astrophysics Data System (ADS)

The 1.6 m clear aperture, off-axis New Solar Telescope (NST) is in regular operation in Big Bear Solar Observatory. The NST is the first facility-class solar telescope built in the U.S. in a generation. The NST provides high resolution and high sensitivity observations of the solar photosphere and chromosphere in the visible and near infrared (NIR). A high order adaptive optics system delivers corrected light to an ensemble of state-of-the-art scientific instruments in the coude laboratory including the Broad-band Filter Imagers (BFIs), NIR Imaging Spectro-polarimeter (NIRIS), Visible Imaging Spectro-polarimeter (VIS) and Fast Imaging Solar Spectrograph (FISS). Some early scientific results from the NST will be presented, followed by a progress report on NST instrument development projects, as well as upgrades to existing instruments.

Cao, W.

2012-12-01

80

Science with Large Solar Telescopes: Overview of SpS 6  

NASA Astrophysics Data System (ADS)

With several large aperture optical and IR telescopes just coming on-line, or scheduled for the near future, solar physics is on the verge of a quantum leap in observational capabilities. An efficient use of such facilities will require new and innovative approaches to both observatory operations and data handling. This two-days long Special Session discussed the science expected with large solar telescopes, and started addressing the strategies necessary to optimize their scientific return. Cutting edge solar science as derived from state-of-the-art observations and numerical simulations and modeling was presented, and discussions were held on the role of large facilities in satisfying the demanding requirements of spatial and temporal resolution, stray-light correction, and spectro-polarimetric accuracy. Building on the experience of recently commissioned telescopes, critical issues for the development of future facilities were discussed. These included operational issues peculiar to large telecopes as well as strategies for their best use.

Cauzzi, Gianna; Tritschler, Alexandra; Deng, Yuanyong

2015-03-01

81

Optical design and testing of a fast, large aperture, infrared space telescope  

NASA Technical Reports Server (NTRS)

An optical design study for a next generation infrared space telescope has been performed. The concept is that of a passively cooled telescope of minimum aperture 2.5 m with an F/1.2 primary and wavelength coverage from 2 to as least 40 microns, and possibly to 100 microns. Compactness, low thermal emission from the optics and structure, diffraction limited imaging at 2 microns, and sensitivity to misalignment aberrations and manufacturing errors were the main considerations for this study. Ray tracing results are presented showing the characteristics of the various designs considered. A preliminary investigation of stray light properties is also given. Special emphasis has been placed on the testing of such a fast primary, and optical systems using a lateral shearing interferometer are described for testing both the primary and the primary/secondary combination.

Humphries, C. M.; Nevo, Y.; Ettedgui-Atad, E.; Harris, J. W.

1992-01-01

82

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

83

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.

84

High-contrast imaging testbed for Complex Aperture Telescopes (HiCAT) for future space missions  

NASA Astrophysics Data System (ADS)

Searching for nearby habitable worlds with direct imaging and spectroscopy will require a telescope large enough to provide angular resolution and sensitivity to planets around a significant sample of stars. Segmented telescopes are a compelling option to obtain such large apertures. However, these designs have a complex geometry (central obstruction, support structures, segmentation) that makes high contrast imaging challenging. We are developing a new high-contrast imaging testbed at STScI to provide an integrated solution for wavefront control and starlight suppression on complex aperture geometries. We present a novel optimization approach for the testbed optical and opto-mechanical design that minimizes the impact of both phase and amplitude errors from the wave propagation of testbed optics surface errors. This design approach allows us to define the specification for the bench optics, which we then compare to the manufactured parts. We discuss the testbed alignment and first results. We also present our coronagraph design for different testbed pupil shapes (AFTA or ATLAST), which involves a new method for the optimization of Apodized Pupil Lyot Coronagraphs (APLC).

Choquet, E.; N'Diaye, M.; Pueyo, L.; Elliot, E.; Perrin, M. D.; Wallace, J. K.; Anderson, R.; Carlotti, A.; Groff, T.; Hartig, G.; Kasdin, N. J.; Lajoie, C.; Levecq, O.; Long, C.; Mawet, D.; Macintosh, B.; Norman, C.; Shaklan, S.; Sheckells, M.; Sivaramakrishnan, An; Soummer, R.

2014-03-01

85

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

86

Experimental demonstration of a self-tracking 16-aperture receiver telescope array for laser intersatellite communications  

NASA Astrophysics Data System (ADS)

An adaptive receive telescope array with 16 apertures has been designed and breadboarded. With respect to size and performance, such a telescope array is well suited for use as receive antenna in a coherent interorbit laser link. The laboratory demonstrator, designed to operate at a wavelength of (lambda) equals 1.064 micrometers, is completely independent of any subsequent receiver and of the data modulation format employed. The telescope array is self-phasing, i.e. the main lobe of the antenna pattern automatically follows the direction of the incident wave. It thus performs non- mechanical fine tracking. Our experimental setup comprises a subtelescope array and a digital control unit employing digital signal processors. Besides inertia-free tracking, the control unit also checks and, if necessary, restores parallel alignment of the subtelescope axes at regular intervals. Space-worthy concepts have been applied wherever possible, although experiments have been performed only in the laboratory. Automatic fine-tracking is achieved within a single subtelescope's field of view (30 (mu) rad) in the frequency range up to 730 Hz.

Kalmar, Andras; Kudielka, Klaus H.; Leeb, Walter R.

1998-05-01

87

Results of aperture area comparisons for exo-atmospheric total solar irradiance measurements.  

PubMed

Exo-atmospheric solar irradiance measurements made by the solar irradiance community since 1978 have incorporated limiting apertures with diameters measured by a number of metrology laboratories using a variety of techniques. Knowledge of the aperture area is a critical component in the conversion of radiant flux measurements to solar irradiance. A National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) sponsored international comparison of aperture area measurements of limiting apertures provided by solar irradiance researchers was performed, the effort being executed by the National Institute of Standards and Technology (NIST) in coordination with the EOS Project Science Office. Apertures that had institutional heritage with historical solar irradiance measurements were measured using the absolute aperture measurement facility at NIST. The measurement technique employed noncontact video microscopy using high-accuracy translation stages. We have quantified the differences between the participating institutions' aperture area measurements and find no evidence to support the hypothesis that preflight aperture area measurements were the root cause of discrepancies in long-term total solar irradiance satellite measurements. Another result is the assessment of uncertainties assigned to methods used by participants. We find that uncertainties assigned to a participant's values may be underestimated. PMID:24513747

Johnson, B Carol; Litorja, Maritoni; Fowler, Joel B; Shirley, Eric L; Barnes, Robert A; Butler, James J

2013-11-20

88

Integrating Seeing Measurements into the Operations of Solar Telescopes  

E-print Network

gathering power is the 4-meter ATST7 under the stewardship of the National Solar Observatory, which has conditions for solar observations: Big Bear Solar Observatory in California, Haleakala on Maui, HawaiiIntegrating Seeing Measurements into the Operations of Solar Telescopes C. Denker and A. P. Verdoni

89

Initial Results of Aperture Area Comparisons for Exo-Atmospheric Total Solar Irradiance Measurements  

NASA Technical Reports Server (NTRS)

In the measurement of exo-atmospheric total solar irradiance (TSI), instrument aperture area is a critical component in converting solar radiant flux to irradiance. In a May 2000 calibration workshop for the Total Irradiance Monitor (TIM) on the Earth Observing System (EOS) Solar Radiation and Climate Experiment (SORCE), the solar irradiance measurement community recommended that NASA and NISI coordinate an aperture area measurement comparison to quantify and validate aperture area uncertainties and their overall effect on TSI uncertainties. From May 2003 to February 2006, apertures from 4 institutions with links to the historical TSI database were measured by NIST and the results were compared to the aperture area determined by each institution. The initial results of these comparisons are presented and preliminary assessments of the participants' uncertainties are discussed.

Johnson, B. Carol; Litorja, Maritoni; Fowler, Joel B.; Butler, James J.

2009-01-01

90

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

91

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.; Angilè, 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

92

Secondary mirror system for the European Solar Telescope (EST)  

Microsoft Academic Search

The European Solar Telescope (EST) is a European collaborative project to build a 4m class solar telescope in the Canary Islands, which is now in its design study phase. The telescope will provide diffraction limited performance for several instruments observing simultaneously at the Coudé focus at different wavelengths. A multi-conjugated adaptive optics system composed of a tip-tilt mirror and several

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

2010-01-01

93

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

2008-09-25

94

CAMERA: a compact, automated, laser adaptive optics system for small aperture telescopes  

NASA Astrophysics Data System (ADS)

CAMERA is an autonomous laser guide star adaptive optics system designed for small aperture telescopes. This system is intended to be mounted permanently on such a telescope to provide large amounts of flexibly scheduled observing time, delivering high angular resolution imagery in the visible and near infrared. The design employs a Shack Hartmann wavefront sensor, a 12x12 actuator MEMS device for high order wavefront compensation, and a solid state 355nm ND:YAG laser to generate a guide star. Commercial CCD and InGaAs detectors provide coverage in the visible and near infrared. CAMERA operates by selecting targets from a queue populated by users and executing these observations autonomously. This robotic system is targeted towards applications that are diffcult to address using classical observing strategies: surveys of very large target lists, recurrently scheduled observations, and rapid response followup of transient objects. This system has been designed and costed, and a lab testbed has been developed to evaluate key components and validate autonomous operations.

Britton, Matthew; Velur, Viswa; Law, Nick; Choi, Philip; Penprase, Bryan E.

2008-07-01

95

Structural Feasibility Analysis of a Robotically Assembled Very Large Aperture Optical Space Telescope  

NASA Technical Reports Server (NTRS)

This paper presents a feasibility study of robotically constructing a very large aperture optical space telescope on-orbit. Since the largest engineering challenges are likely to reside in the design and assembly of the 150-m diameter primary reflector, this preliminary study focuses on this component. The same technology developed for construction of the primary would then be readily used for the smaller optical structures (secondary, tertiary, etc.). A reasonable set of ground and on-orbit loading scenarios are compiled from the literature and used to define the structural performance requirements and size the primary reflector. A surface precision analysis shows that active adjustment of the primary structure is required in order to meet stringent optical surface requirements. Two potential actuation strategies are discussed along with potential actuation devices at the current state of the art. The finding of this research effort indicate that successful technology development combined with further analysis will likely enable such a telescope to be built in the future.

Wilkie, William Keats; Williams, R. Brett; Agnes, Gregory S.; Wilcox, Brian H.

2007-01-01

96

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

NASA Astrophysics Data System (ADS)

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 2m 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 ?m. The diffraction-limited optical system provides a resolution of 30" at 250 ?m. The pointing system enables raster-like scans with a positional accuracy of ~30", reconstructed to better than 5" rms in postflight 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 deg2) 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.

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

2008-07-01

97

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

structures drive us to build large-aperture solar telescopes and state-of-the-art facility- class instruments instrumentation for the 1.6 m New Solar Telescope in Big Bear W. Cao1,2, , N. Gorceix2 , R. Coulter2 , K. Ahn3 , T 2010 Mar 29 Published online 2010 Jun 17 Key words instrumentation: adaptive optics ­ instrumentation

98

New solar telescope in Big Bear: evidence for super-diffusivity and small-scale solar dynamos?  

NASA Astrophysics Data System (ADS)

The 1.6 m clear aperture New Solar Telescope (NST) in Big Bear Solar Observatory (BBSO) is now providing the highest resolution solar data ever. These data have revealed surprises about the Sun on small-scales including the observation that bright points (BPs), which can be used as proxies for the intense, compact magnetic elements that are apparent in photospheric intergranular lanes. The BPs are ever more numerous on ever smaller spatial scales as though there were no limit to how small the BPs can be. Here we discuss high resolution NST data on BPs that provide support for the ideas that a turbulent regime of super-diffusivity dominates in the quiet Sun, and there are local dynamos operating near the solar surface.

Goode, Philip R.; Abramenko, Valentyna; Yurchyshyn, Vasyl

2012-07-01

99

Spillage and flux density on a receiver aperture lip. [of solar thermal collector  

NASA Technical Reports Server (NTRS)

In a dish-type point-focusing solar thermal collector, the spillage and the flux density on the receiver aperture lip are related in a very simple way, if the aperture is circular and centered on the optical axis. Specifically, the flux density on the lip is equal to the spillage times the peak flux density in the plane of the lip.

Jaffe, L. D.

1985-01-01

100

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 Å is 35 mÅ. Calibration is carried-out for the Fe I 6173 Å, H-alpha 6563 Å and Ca K 8542 Å. Free spectral range (FSR) obtained for FP1 and FP2 in tandem for 6173 Å is 6.7Å and 150 mÅ respectively. Voltage range of the system allows us to scan the entire line profile of 6173 in the range of ±220 mÅ with a sampling of 20 mÅ. 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

101

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

102

Ground demonstration of an optical control system for a space-based sparse-aperture telescope  

NASA Astrophysics Data System (ADS)

SVS has recently completed a phase II small business innovative research (SBIR) project called low cost space imager (LCSI). As part of the SBIR project, a sparse aperture telescope design concept was developed. This design includes an optical control system capable of correcting the primary segments to within 38 nm piston and 17 nrad tilt as required by the optical tolerance analysis. The optical system utilizes a common secondary and primaries arranged in a Golay-6 configuration. The primaries are spherical, which eliminates the need for translation and rotation control. A laboratory experiment to validate the controls concept has been completed. This experiment culminated in the demonstration of autonomous capture, alignment, and phasing of an optical system with a three segment primary to tolerances consistent with the space optical system. The implementation of the controls scheme in the laboratory experiment is done using Matlab/Simulink for controller design and code generation the code is implemented real-time on a VME based computer system. Closed loop piston control, which utilizes a four-bin sensing scheme, of an actuated mirror to 25 nm RMS mirror motion has been demonstrated. Additionally, autonomous capture and phasing of three segmented primaries has been demonstrated. The technique for the phasing capture involves real-time implementation of image processing techniques to measure the white light fringe visibility in the far field.

De Young, David B.; Dillow, James; Corcoran, Stephen P.; Andrews, Edwina V.; Yellowhair, Julius; Devries, Kevin

1998-08-01

103

Ground demonstration of an optical control system for a space-based sparse aperture telescope  

NASA Astrophysics Data System (ADS)

SVS has recently completed a phase II small business innovative research (SBIR) project called Low Cost Space Imager. As part of the SBIR project, a sparse aperture telescope design concept was developed. This design includes an optical control system capable of correcting the primary segments to within 38 nm piston and 17 nrad tilt as required by the optical tolerance analysis. The optical system utilizes a common secondary and primaries arranged in a Golay-6 configuration. The primaries are spherical, which eliminates the need for translation and rotation control. A laboratory experiment to validate the controls concept has ben completed. This experiment culminated in the demonstration of autonomous capture, alignment, and phasing of an optical system with a three segment primary to tolerances consistent with the space optical system. The implementation of the controls scheme in the laboratory experiment is done using Matlab/Simulink for controller design and code generation. The code is implemented real- time on a VME based computer system. Closed loop piston control, which utilizes a four-bin sensing scheme, of an actuated mirror to 25 nm RMS mirror motion has been demonstrated. Additionally, autonomous capture and phasing of three segmented primaries has been demonstrated. The technique for the phasing capture involves real-time implementation of image processing techniques to measure the white light fringe visibility in the far field.

De Young, David B.; Dillow, James; Corcoran, Stephen; Andrews, Edwina V.; Yellowhair, Julius; Devries, Kevin

1998-09-01

104

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

105

AGN and quasar science with aperture masking interferometry on the James Webb Space Telescope  

E-print Network

Due to feedback from accretion onto supermassive black holes (SMBHs), Active Galactic Nuclei (AGNs) are believed to play a key role in LambdaCDM cosmology and galaxy formation. However, AGNs' extreme luminosities and the small angular size of their accretion flows create a challenging imaging problem. We show James Webb Space Telescope's Near Infrared Imager and Slitless Spectrograph (JWST-NIRISS) Aperture Masking Interferometry (AMI) mode will enable true imaging (i.e. without any requirement of prior assumptions on source geometry) at ~65 mas angular resolution at the centers of AGNs. This is advantageous for studying complex extended accretion flows around SMBHs, and in other areas of angular-resolution-limited astrophysics. By simulating data sequences incorporating expected sources of noise, we demonstrate that JWST-NIRISS AMI mode can map extended structure at a pixel-to-pixel contrast of ~10^{-2} around an L=7.5 point source, using short exposure times (minutes). Such images will test models of AGN fee...

Ford, K E Saavik; Sivaramakrishnan, Anand; Martel, André R; Koekemoer, Anton; Lafrenière, David; Parmentier, Sébastien

2014-01-01

106

The electromagnetic properties of aperture-synthesis telescopes shaped as Reuleaux triangles  

NASA Astrophysics Data System (ADS)

The electromagnetic properties of aperture-synthesis telescopes in the form of an array of identical antennas sited on the sides of an equilateral Reuleaux triangle are studied in the limit that the number of antennas becomes arbitrarily large. The density of baselines in the uv-plane is derived exactly and is found to be highly irregular: it has seven singularities and 13 finite discontinuities, and is not even approximately circularly symmetric. The response pattern of the synthesized beam is computed numerically and is also found not to be circularly symmetric, although only to a moderate extent. The properties are compared with those of the circular ring array and found to be very similar: the main differences are that the synthesized beam of the Reuleaux triangle is 4 per cent broader than that of the circle with the same diameter whereas the average sidelobe level is 10 per cent lower. The Reuleaux triangle came to attention in a search for the shape of array that gives the most uniform coverage of baselines in the uv-plane, and a discussion is presented whether it really is optimal in this regard.

Webster, Adrian

2004-10-01

107

High-flux, high-temperature thermal vacuum qualification testing of a solar receiver aperture shield  

Microsoft Academic Search

To verify its thermal-structural durability under anticipated high-flux, high-temperature loading, a solar dynamic power system receiver aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar

Thomas W. Kerslake; Lee S. Mason; Hal J. Strumpf

1997-01-01

108

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

E-print Network

Rather than using an adaptive optics (AO) system to correct a telescope s entire pupil, it can instead be used to more finely correct a smaller sub-aperture. Indeed, existing AO systems can be used to correct a sub-aperture 1/3 to 1/2 the size of a 5-10 m telescope to extreme adaptive optics (ExAO) levels. We discuss the potential performance of a clear off-axis well-corrected sub-aperture (WCS), and describe our initial imaging results with a 1.5 m diameter WCS on the Palomar Observatory s Hale telescope. These include measured Strehl ratios of 0.92-0.94 in the infrared (2.17 microns), and 0.12 in the B band, the latter allowing a binary of separation 0.34 arc sec to be easily resolved in the blue. Such performance levels enable a variety of novel observational modes, such as infrared ExAO, visible-wavelength AO, and high-contrast coronagraphy. One specific application suggested by the high Strehl ratio stability obtained (1%) is the measurement of planetary transits and eclipses. Also described is a simple dark-hole experiment carried out on a binary star, in which a comatic phase term was applied directly to the deformable mirror, in order to shift the diffraction rings to one side of the point spread function.

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

2007-02-21

109

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

110

Selecting the site for the advanced technology solar telescope  

Microsoft Academic Search

Instrumentation and analysis methods have been developed to provide sky brightness and daytime seeing as a function of height at different locations. To measure magnetic fields in the sun's outer atmosphere (the corona), and to provide the highest spatial resolution solar im- ages ever achieved, the Advanced Technology Solar Telescope (ATST) must be located at a site with excellent daytime

Frank Hill

2006-01-01

111

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

112

Design and Analysis of the Aperture Shield Assembly for a Space Solar Receiver  

NASA Technical Reports Server (NTRS)

A joint U.S./Russia program has been conducted to design, develop, fabricate, launch, and operate the world's first space solar dynamic power system on the Russian Space Station Mir. The goal of the program was to demonstrate and confirm that solar dynamic power systems are viable for future space applications such as the International Space Station (ISS). The major components of the system include a solar receiver, a closed Brayton cycle power conversion unit, a power conditioning and control unit, a solar concentrator, a radiator, a thermal control system, and a Space Shuttle carrier. Unfortunately, the mission was demanifested from the ISS Phase 1 Space Shuttle Program in 1996. However, NASA Lewis is proposing to use the fabricated flight hardware as part of an all-American flight demonstration on the ISS in 2002. The present paper concerns the design and analysis of the solar receiver aperture shield assembly. The aperture shield assembly comprises the front face of the cylindrical receiver and is located at the focal plane of the solar concentrator. The aperture shield assembly is a critical component that protects the solar receiver structure from highly concentrated solar fluxes during concentrator off-pointing events. A full-size aperture shield assembly was fabricated. This unit was essentially identical to the flight configuration, with the exception of materials substitution. In addition, a thermal shock test aperture shield assembly was fabricated. This test article utilized the flight materials and was used for high-flux testing in the solar simulator test rig at NASA Lewis. This testing is described in a companion paper.

Strumpf, Hal J.; Trinh, Tuan; Westelaken, William; Krystkowiak, Christopher; Avanessian, Vahe; Kerslake, Thomas W.

1997-01-01

113

Multi-Application Solar Telescope: assembly, integration, and testing  

NASA Astrophysics Data System (ADS)

The Multi-Application Solar Telescope (MAST) is a 50 cm diameter class telescope to be installed by AMOS on the Udaipur Solar Observatory's Island on the Lake Fatehsagar in India. Despite its limited size, the telescope is expected to be competitive with respect to worldwide large and costly projects thanks to its versatility regarding science goals and due to its demanding optomechanical and thermal specification. This paper describes the latest, on-going and forthcoming activities, including factory assembly, integration and testing, followed by on-site installation and commissioning activities. Emphasis is put on the highly demanding thermal control of the telescope, showing development and results for the specific techniques employed on this purpose. Other key features also depicted are the unusual tracking and alignment control solutions on such a specific science target like the Sun.

Denis, Stefan; Coucke, Pierre; Gabriel, Eric; Delrez, Christophe; Venkatakrishnan, Parameshwaran

2010-07-01

114

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

115

Manufacturing of space telescope solar array blankets  

Microsoft Academic Search

Fabrication details are listed for the flexible substrate and solar cell array subsections, including the bonding of the cells to the substrate. A vacuum device is used to position each array subsection. Adhesive is applied to the substrate with a screen printing technique. A special jig is described which is used for the interconnection of the solar panel assemblies and

G. Kuechler

1980-01-01

116

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

117

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

118

BAT Slew Survey (BATSS): Slew Data Analysis for the Swift-BAT Coded Aperture Imaging Telescope  

NASA Astrophysics Data System (ADS)

The BAT Slew Survey (BATSS) is the first wide-field survey of the hard X-ray sky (15--150 keV) with a slewing coded aperture imaging telescope. Its fine time resolution, high sensitivity and large sky coverage make it particularly well-suited for detections of transient sources with variability timescales in the ˜1 sec--1 hour range, such as Gamma-Ray Bursts (GRBs), flaring stars and Blazars. As implemented, BATSS observations are found to be consistently more sensitive than their BAT pointing-mode counterparts, by an average of 20% over the 10 sec--3 ksec exposure range, due to intrinsic systematic differences between them. The survey's motivation, development and implementation are presented, including a description of the software and hardware infrastructure that made this effort possible. The analysis of BATSS science data concentrates on the results of the 4.8-year BATSS GRB survey, beginning with the discovery of GRB 070326 during its preliminary testing phase. A total of nineteen (19) GRBs were detected exclusively in BATSS slews over this period, making it the largest contribution to the Swift GRB catalog from all ground-based analysis. The timing and spectral properties of prompt emission from BATSS GRBs reveal their consistency with Swift long GRBs (L-GRBs), though with instances of GRBs with unusually soft spectra or X-Ray Flashes (XRFs), GRBs near the faint end of the fluence distribution accessible to Swift -BAT, and a probable short GRB with extended emission, all uncommon traits within the general Swift GRB population. In addition, the BATSS overall detection rate of 0.49 GRBs/day of instrument time is a significant increase (45%) above the BAT pointing detection rate. This result was confirmed by a GRB detection simulation model, which further showed the increased sky coverage of slews to be the dominant effect in enhancing GRB detection probabilities. A review of lessons learned is included, with specific proposals to broaden both the number and range of astrophysical sources found in future enhancements. The BATSS survey results provide solid empirical evidence in support of an all-slewing hard X-ray survey mission, a prospect that may be realized with the launch of the proposed MIRAX-HXI mission in 2017.

Copete, Antonio Julio

119

Optomechanical and thermal design of the Multi-Application Solar Telescope for USO  

Microsoft Academic Search

The Multi-Application Solar Telescope (MAST) is a 50 cm diameter class telescope to be installed on the Udaipur Solar Observatory's Island on the Lake Fatehsagar in Udaipur, India. It is dedicated to solar observation. The telescope is designed, manufactured, assembled and installed on-site by the belgian company AMOS SA for the Udaipur Solar Observatory (USO), an academic division of the

Stefan Denis; Pierre Coucke; Eric Gabriel; Christophe Delrez; Parameshwaran Venkatakrishnan

2008-01-01

120

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

121

Application of a white-light interferometric measuring system as co-phasing the segmented primary mirrors of the high-aperture telescope  

Microsoft Academic Search

For the optical system of the telescope, with the increase in telescope size, the manufacture of monolithic primary becomes increasingly difficult. Instead, the use of segmented mirrors, where many individual mirrors (the segments) work together to provide an image quality and an aperture equivalent to that of a large monolithic mirror, is considered a more appropriate strategy. But with the

Helun Song; Huaqiang Li; Hao Xian; Jian Huang; Shengqian Wang; Wenhan Jiang

2008-01-01

122

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

123

Polarization Calibration of the Solar Optical Telescope onboard Hinode  

Microsoft Academic Search

The Solar Optical Telescope (SOT) onboard Hinode aims to obtain vector magnetic fields on the Sun through precise spectropolarimetry of solar spectral lines with a spatial\\u000a resolution of 0.2?–?0.3 arcsec. A photometric accuracy of 10?3 is achieved and, after the polarization calibration, any artificial polarization from crosstalk among Stokes parameters is\\u000a required to be suppressed below the level of the statistical noise

K. Ichimoto; B. Lites; D. Elmore; Y. Suematsu; S. Tsuneta; Y. Katsukawa; T. Shimizu; R. Shine; T. Tarbell; J. Kiyohara; K. Shinoda; G. Card; A. Lecinski; K. Streander; M. Nakagiri; M. Miyashita; M. Noguchi; C. Hoffmann; T. Cruz

2008-01-01

124

High-Flux, High-Temperature Thermal Vacuum Qualification Testing of a Solar Receiver Aperture Shield  

NASA Technical Reports Server (NTRS)

As part of the International Space Station (ISS) Phase 1 program, NASA Lewis Research Center (LERC) and the Russian Space Agency (RSA) teamed together to design, build and flight test the world's first orbital Solar Dynamic Power System (SDPS) on the Russian space station Mir. The Solar Dynamic Flight Demonstration (SDFD) program was to operate a nominal 2 kWe SDPS on Mir for a period up to 1-year starting in late 1997. Unfortunately, the SDFD mission was demanifested from the ISS phase 1 shuttle program in early 1996. However, substantial flight hardware and prototypical flight hardware was built including a heat receiver and aperture shield. The aperture shield comprises the front face of the cylindrical cavity heat receiver and is located at the focal plane of the solar concentrator. It is constructed of a stainless steel plate with a 1-m outside diameter, a 0.24-m inside diameter and covered with high-temperature, refractory metal Multi-Foil Insulation (MFI). The aperture shield must minimize heat loss from the receiver cavity, provide a stiff, high strength structure to accommodate shuttle launch loads and protect receiver structures from highly concentrated solar fluxes during concentrator off-pointing events. To satisfy Mir operational safety protocols, the aperture shield was required to accommodate direct impingement of the intensely concentrated solar image for a 1-hour period. To verify thermal-structural durability under the anticipated high-flux, high-temperature loading, an aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar flux for a period of 1-hour. In the first test, a near equilibrium temperature of 1862 K was attained in the center of the shield hot spot. In the second test, with increased incident flux, a near equilibrium temperature of 2072 K was achieved. The aperture shield sustained no visible damage as a result of the exposures. This paper describes the aperture shield thermal-vacuum qualification test program including the test article, test facility, procedures, data collection, test success criteria, results and conclusions.

Kerslake, Thomas W.; Mason, Lee S.; Strumpf, Hal J.

1997-01-01

125

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

126

The cern axion solar telescope (CAST): an update  

Microsoft Academic Search

The CERN Axion Solar Telescope (CAST), a 10 meter long LHC, 9 Tesla, test magnet is mounted on a moving platform that tracks the sun about 1.5 hours during sunrise, again during sunset. It moves ±80 vertically and ±400 horizontally. It has been taking data continuously since July 10, 2003. Data analyzed thus far yield an upper bound on the

S. Andriamonje; V. Arsov; S. Aune; T. Aune; F AVIGNONEIII; K. Barth; A. Belov; B. Beltran; H. Bräuninger; J. Carmona; S. Cebrián; E. Chesi; G. Cipolla; J. Collar; R. Creswick; T. Dafni; M. Davenport; S. Dedousis; M. Delattre; A. Delbart; R. Deoliveira; L. Dilella; C. Eleftheriadis; J. Engelhauser; G. Fanourakis; H. Farach; E. Ferrer; H. Fischer; F. Formenti; J. Franz; P. Friedrich; T. Geralis; I. Giomataris; S. Gninenko; N. Golubev; R. Hartmann; M. Hasinoff; F. H. Heinsius; D. H. H. Hoffmann; I. Irastorza; J. Jacoby; J. N. Joux; D. Kang; K. Königsmann; R. Kotthaus; M. Krcmar; M. Kuster; B. Lakic; C. Lasseur; A. Liolios; A. Lippitsch; A. Ljubicic; G. Lutz; G. Luzon; A. Morales; J. Morales; M. Mutterer; A. Nikolaidis; A. Ortiz de Solorzano; T. Papaevangelou; A. Placci; G. Raffelt; P. Rammos; J. P. Robert; J. Ruz; M. Sarsa; C. Schill; W. Serber; Y. Semertzidis; J. Vieira; J. Villar; B. Vullierme; L. Walckiers; K. Zioutas

2005-01-01

127

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

128

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

129

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

130

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

131

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

132

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

133

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

134

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

135

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

136

Solar tests of aperture plate materials for solar thermal dish collectors  

SciTech Connect

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

137

SolarB X-Ray Telescope (XRT)  

NASA Astrophysics Data System (ADS)

The Soft X-ray Telescope (XRT) aboard SolarB is a grazing incidence X-ray telescope equipped with 2k × 2k CCD. XRT has 1 arcsec resolution with wide field-of-view of 34 × 34 arcmin. It is sensitive to <1 MK to 30 MK, allowing us to obtain TRACE-like low temperature images as well. Co-alignment with SOT and EIS is realized through the XRT visible light telescope and with temperature overlap with EIS. Spacecraft mission data processor (MDP) controls XRT through the sequence tables with versatile autonomous functions such as exposure control, region-of-interest tracking, flare detection and flare location identification. Data are compressed either with DPCM or JPEG, depending on the purpose. This results in higher cadence and/or wider field-of-view for given telemetry bandwidth. With focus adjust mechanism, higher resolution of Gaussian focus may be available on-axis.

Kano, R.; Hara, H.; Shimojo, M.; Tsuneta, S.; Sakao, T.; Matsuzaki, K.; Kosugi, T.; Golub, L.; Deluca, E. E.; Bookbinder, J. A.; Cheimets, P.; Owens, J. K.; Hill, L. D.

2004-12-01

138

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

139

The Lyman-alpha Imager onboard Solar Polar Orbit Telescope  

NASA Astrophysics Data System (ADS)

Solar Polar ORbit Telescope (SPORT) was originally proposed in 2004 by the National Space Science Center, Chinese Academy of Sciences, which is currently being under background engineering study phase in China. SPORT will carry a suite of remote-sensing and in-situ instruments to observe coronal mass ejections (CMEs), solar high-latitude magnetism, and the fast solar wind from a polar orbit around the Sun. The Lyman-alpha Imager (LMI) is one of the key remotesensing instruments onboard SPORT with 45arcmin FOV, 2000mm effective focal length and 1.4arcsec/pixel spatial resolution . The size of LMI is ?150×1000mm, and the weight is less than10kg, including the 7kg telescope tube and 3kg electronic box. There are three 121.6nm filters used in the LMI optical path, so the 98% spectral purity image of 121.6nm can be achieved. The 121.6nm solar Lyman-alpha line is produced in the chromosphere and very sensitive to plasma temperature, plasma velocity and magnetism variation in the chromosphere. Solar Lyman-alpha disk image is an ideal tracker for corona magnetism variation.

Li, Baoquan; Li, Haitao; Zhou, Sizhong; Jiang, Bo

2013-12-01

140

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

141

Observing Solar System Objects with the James Webb Space Telescope  

Microsoft Academic Search

The James Webb Space Telescope (JWST) will have the capability to observe Solar System objects having apparent rates of motion up to 30 milli-arcseconds\\/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

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

2009-01-01

142

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

143

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

144

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

145

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

146

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

147

NIRIS: The Second Generation Near-Infrared Imaging Spectro-polarimeter for the 1.6 Meter New Solar Telescope  

NASA Astrophysics Data System (ADS)

The largest aperture solar telescope, the 1.6 m New Solar Telescope (NST) has been installed at the Big Bear Solar Observatory (BBSO). To take full advantage of the NST's greatest potential, we are upgrading the routinely operational InfraRed Imaging Magnetograph (IRIM) to its second generation, the NIRIS (Near-InfraRed Imaging Spectropolarimeter). NIRIS will offer unprecedented high resolution spectroscopic and polarimetric imaging data of the solar atmosphere from the deepest photosphere through the base of the corona. With the aid of the BBSO adaptive optics (AO) system, the spatial resolution will be close to the diffraction limit of the NST. The spectroscopic cadence will reach one second, while polarimetric measurements, including Stokes I, Q, U, V profiles, remain at a better than 10 s cadence. Polarization sensitivity is expected to be reach ˜ 10-4Ic. NIRIS will cover a broad spectral range from 1.0 to 1.7?m, with particular attention to two unique spectral lines: the Fe I 1565 nm doublet has already proven to be the most sensitive to Zeeman effect for probing the magnetic field in the deepest photosphere; the He I 1083 nm multiplet is one of the best currently available diagnostic of upper chromospheric magnetic fields that allows one to map the vector field at the base of the corona. NIRIS will be built on dual Fabry-Pérot Interferometers (FPIs), each of which has an aperture of 100 mm. The larger aperture of FPIs allows the available field-of-view up to one and half minutes with a spectral power of ˜ 105.

Cao, W.; Goode, P. R.; Ahn, K.; Gorceix, N.; Schmidt, W.; Lin, H.

2012-12-01

148

Design Requirements and Component Down Selection Process for an Aperture Masking Instrument at the Magdalena Ridge Observatory 2.4m Telescope  

Microsoft Academic Search

The design of a new instrument requires careful consideration of all components to ensure that design specifications are met while staying within the prescribed budget. This poster presents the down selection process for the major components of a new instrument for the Magdalena Ridge Observatory 2.4m telescope. This instrument is designed primarily for aperture masking at optical wavelengths, a technique

Luke M. Schmidt; S. W. Teare; D. J. Westpfahl; C. A. Jurgenson

2009-01-01

149

Extra Solar Planetary Imaging Coronagraph and Science Requirements for the James Webb Telescope Observatory  

NASA Technical Reports Server (NTRS)

1) Extra solar planetary imaging coronagraph. Direct detection and characterization of Jovian planets, and other gas giants, in orbit around nearby stars is a necessary precursor to Terrestrial Planet Finder 0 in order to estimate the probability of Terrestrial planets in our stellar neighborhood. Ground based indirect methods are biased towards large close in Jovian planets in solar systems unlikely io harbor Earthlike planets. Thus to estimate the relative abundances of terrestrial planets and to determine optimal observing strategies for TPF a pathfinder mission would be desired. The Extra-Solar Planetary Imaging Coronagraph (EPIC) is such a pathfinder mission. Upto 83 stellar systems are accessible with a 1.5 meter unobscured telescope and coronagraph combination located at the Earth-Sun L2 point. Incorporating radiometric and angular resolution considerations show that Jovians could be directly detected (5 sigma) in the 0.5 - 1.0 micron band outside of an inner working distance of 5/D with integration times of -10 - 100 hours per observation. The primary considerations for a planet imager are optical wavefront quality due to manufacturing, alignment, structural and thermal considerations. pointing stability and control, and manufacturability of coronagraphic masks and stops to increase the planetary-to- stellar contrast and mitigate against straylight. Previously proposed coronagraphic concepts are driven to extreme tolerances. however. we have developed and studied a mission, telescope and coronagraphic detection concept, which is achievable in the time frame of a Discovery class NASA mission. 2) Science requirements for the James Webb Space Telescope observatory. The James Webb Space Observatory (JWST) is an infrared observatory, which will be launched in 201 1 to an orbit at L2. JWST is a segmented, 18 mirror segment telescope with a diameter of 6.5 meters, and a clear aperture of 25 mA2. The telescope is designed to conduct imaging and spectroscopic observations from 0.6-27 microns. The primary mirror find and understand predicted first light objects, observe galaxies back to their earliest precursors so that we can understand their growth and evolution, unravel the birth and early evolution of stars and planetary systems, and study planetary systems and the origins of life. In this paper we discuss the science goals for JWST in the context of the performance requirements they levy on the observatory.

Clampin, Mark

2004-01-01

150

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.; Peñate, J.; Pérez, A.; Scharmer, G. B.; Sliepen, G.; Soltau, D.; Waldmann, T. A.; van Werkhoven, T.

2010-07-01

151

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

152

A balloon-borne coded aperture telescope for low-energy gamma-ray astronomy  

Microsoft Academic Search

A telescope for imaging cosmic gamma-ray emission over the energy range 160 keV to 9.3 MeV has been developed and successfully flown on a high altitude balloon over Palestine, Texas on 1 October, 1984. This instrument consists of a coded mask based on a 5 × 7 uniformly redundant array (URA) and a scintillator array consisting of 35 bismuth germanate

Philip P. Dunphy; Mark L. McConnell; Alan Owens; Edward L. Chupp; David J. Forrest; Jonathan Googins

1989-01-01

153

Compton telescope with coded aperture mask: Imaging with the INTEGRAL/IBIS Compton mode  

E-print Network

Compton telescopes provide a good sensitivity over a wide field of view in the difficult energy range running from a few hundred keV to several MeV. Their angular resolution is, however, poor and strongly energy dependent. We present a novel experimental design associating a coded mask and a Compton detection unit to overcome these pitfalls. It maintains the Compton performance while improving the angular resolution by at least an order of magnitude in the field of view subtended by the mask. This improvement is obtained only at the expense of the efficiency that is reduced by a factor of two. In addition, the background corrections benefit from the coded mask technique, i.e. a simultaneous measurement of the source and background. This design is implemented and tested using the IBIS telescope on board the INTEGRAL satellite to construct images with a 12' resolution over a 29 degrees x 29 degrees field of view in the energy range from 200 keV to a few MeV. The details of the analysis method and the resulting telescope performance, particularly in terms of sensitivity, are presented.

M. Forot; P. Laurent; F. Lebrun; O. Limousin

2007-08-28

154

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

155

Solar Patrol Polarization Telescopes at 45 and 90 GHz  

NASA Astrophysics Data System (ADS)

The spectra of solar flares provide important information about the physics involved in the flaring process. Presently, however, there is a large frequency gap at radio frequencies between 20 and 200 GHz. Unfortunately, this gap hinders the determination of important flare parameters such as: (i) the frequency of the peak of the spectra, or turnover frequency, which yields the magnetic field intensity in the flaring source and electron density; (ii) the optically thin frequency slope, that is related to the accelerated electrons with a power-law energy distribution, allowing information about the acceleration mechanism; (iii) and other physical parameters such as source size and inhomogeneities that may also be estimated from spectra with complete spectral coverage. Recently a new spectral component at high frequencies was discovered with fluxes increasing above 200 GHz, distinct from the traditional microwave component, with peak frequencies at about 10 GHz. To elucidate the nature of both components and fully characterize the spectra of solar flares, we analyze new observations at the intermediate frequencies obtained by two antennas with receivers at 45 and 90 GHz, capable of measuring circular polarization. The telescope, installed at CASLEO Observatory (Argentina), is described in detail. We also analyze the observations of the flares it has already detected, including their spectra especially when data at 212 and 405 GHz from the Solar Submillimeter Telescope (SST), located at the same site, is available.

Valio, A.; Kaufmann, P.; Gimenez de Castro, C. G.; Raulin, J.-P.; Fernandes, L. O.; Marun, A.

2012-12-01

156

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

157

Structural analysis for the 4-m Advanced Technology Solar Telescope (ATST)  

Microsoft Academic Search

With a 4 m off-axis aspherical primary mirror, integrated adaptive optics, low scattered light, infrared coverage, and state-of-the-art post focus instrumentation, the Advanced Technology Solar Telescope (ATST) will be the world's most powerful solar research telescope. In order to achieve the required performance specifications of the telescope, the ATST project selected an alt-az telescope mount to support and position the

Myung K. Cho; Mark Warner; Joon P. Lee

2005-01-01

158

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

159

Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements  

NASA Technical Reports Server (NTRS)

The Advance Mirror Technology Development (AMTD) project is a three year effort initiated in FY12 to mature by at least a half TRL step six critical technologies required to enable 4 to 8 meter UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. A key accomplishment is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints.

Stahl, H. Philip; Postman, Marc; Smith, W. Scott

2013-01-01

160

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

161

Goldhelox: a soft x-ray solar telescope.  

PubMed

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 171-181Å 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. PMID:21307474

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; Savage, M B; Eastman, P F; Jensen, V

1995-01-01

162

Detection of Small-scale Granular Structures in the Quiet Sun with the New Solar Telescope  

NASA Astrophysics Data System (ADS)

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 0farcs0375) 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.; Kitiashvili, I. N.; Kosovichev, A. G.

2012-09-01

163

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

164

Adjustment of a tower solar telescope and spectrograph: A method manual  

NASA Astrophysics Data System (ADS)

Questions of the mounting and adjustment of a tower solar telescope are considered through the example of the TST-2 telescope of the Crimean Astrophysical Observatory Scientific Research Institute. The authors describe the optical circuits of the telescope and spectrograph and list the basic requirements for the mutual arrangement of individual components of the telescope. Simple methods for adjusting elements of the telescope and spectrograph are described.

Stepanian, N. N.; Sunitsa, G. A.; Malashchuk, V. M.

2014-06-01

165

A new controlling system for the solar tower telescope of IZMIRAN. II. A solar image motion compensator  

Microsoft Academic Search

A solar image motion compensator for the solar tower telescope is described. Two mutually perpendicular CCD linear arrays are used as photodetectors. The compensator operates equally effectively in both the pointing and scanning modes.

I. E. Kozhevatov; E. A. Rudenchik; N. P. Cheragin; B. A. Ioshpa; E. Kh. Kulikova; E. G. Bezrukova

2000-01-01

166

Solar Site Survey for the Advanced Technology Solar Telescope. I. Analysis of the Seeing Data  

Microsoft Academic Search

The site survey for the Advanced Technology Solar Telescope concluded recently after more than 2 years of data gathering and analysis. Six locations, including lake, island, and continental sites, were thoroughly probed for image quality and sky brightness. The present paper describes the analysis methodology employed to determine the height stratification of the atmospheric turbulence. This information is crucial, because

H. Socas-Navarro; J. Beckers; P. Brandt; J. Briggs; T. Brown; W. Brown; M. Collados; C. Denker; S. Fletcher; S. Hegwer; F. Hill; T. Horst; M. Komsa; J. Kuhn; A. Lecinski; H. Lin; S. Oncley; M. Penn; T. Rimmele; K. Streander

2005-01-01

167

The Multi-Spectral Solar Telescope Array (MSSTA)  

NASA Technical Reports Server (NTRS)

In 1987, our consortium pioneered the application of normal incidence multilayer X-ray optics to solar physics by obtaining the first high resolution narrow band, "thermally differentiated" images of the corona', using the emissions of the Fe IX/Fe X complex at ((lambda)lambda) approx. 171 A to 175 A, and He II Lyman (beta) at 256 A. Subsequently, we developed a rocket borne solar observatory, the Multi Spectral Solar Telescope Array (MSSTA) that pioneered multi-thermal imaging of the solar atmosphere, using high resolution narrow band X-ray, EUV and FUV optical systems. Analysis of MSSTA observations has resulted in four significant insights into the structure of the solar atmosphere: (1) the diameter of coronal loops is essentially constant along their length; (2) models of the thermal and density structure of polar plumes based on MSSTA observations have been shown to be consistent with the thesis that they are the source of high speed solar wind streams; (3) the magnetic structure of the footpoints of polar plumes is monopolar, and their thermal structure is consistent with the thesis that the chromosphere at their footpoints is heated by conduction from above; (4) coronal bright points are small loops, typically 3,500 - 20,000 km long (5 sec - 30 sec); their footpoints are located at the poles of bipolar magnetic structures that are are distinguished from other network elements by having a brighter Lyman a signature. Loop models derived for 26 bright points are consistent with the thesis that the chromosphere at their footpoints is heated by conduction from the corona.

Walker, A. B. C., Jr.; Barbee, Troy W., Jr.; Hoover, Richard B.

1997-01-01

168

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

169

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

170

BAND-LIMITED CORONAGRAPHS USING A HALFTONE-DOT PROCESS. II. ADVANCES AND LABORATORY RESULTS FOR ARBITRARY TELESCOPE APERTURES  

SciTech Connect

The band-limited coronagraph is a nearly ideal concept that theoretically enables perfect cancellation of all the light of an on-axis source. Over the past several years, several prototypes have been developed and tested in the laboratory, and more emphasis is now on developing optimal technologies that can efficiently deliver the expected high-contrast levels of such a concept. Following the development of an early near-IR demonstrator, we present and discuss the results of a second-generation prototype using halftone-dot technology. We report improvement in the accuracy of the control of the local transmission of the manufactured prototype, which was measured to be less than 1%. This advanced H-band band-limited device demonstrated excellent contrast levels in the laboratory, down to {approx}10{sup -6} at farther angular separations than 3{lambda}/D over 24% spectral bandwidth. These performances outperform the ones of our former prototype by more than an order of magnitude and confirm the maturity of the manufacturing process. Current and next-generation high-contrast instruments can directly benefit from such capabilities. In this context, we experimentally examine the ability of the band-limited coronagraph to withstand various complex telescope apertures.

Martinez, P. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Dorrer, C. [Aktiwave, 241 Ashley Drive, Rochester, NY 14620 (United States); Kasper, M. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany)

2012-01-01

171

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; Angilè, 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

172

Satellite Monitoring, Change Detection, and Characterization Using Non-Resolved Electro-Optical Data from a Small Aperture Telescope  

NASA Astrophysics Data System (ADS)

The Air Force Research Laboratory has been pursuing development of the exploitation of passive reflectance signatures collected from electro-optical sensors to obtain information on man-made satellites. Recent data collection campaigns have acquired filter photometric signatures in the visible regime from satellites in a variety of orbits and under a variety of operating conditions. The orbits include semi-synchronous, geosynchronous, geosynchronous transfer, and supersynchronous. The operating conditions include active, inactive, stable, and unstable. These satellites pose unique challenges because many times they are too distant or too small or both to image using conventional means. Therefore, they are ideal candidates to use to develop techniques that exploit non-resolved photometric intensity measurements to determine status, detect changes, identify, and characterize. The data were collected using a Raven-type sensor system. The telescope has a 16-inch aperture and the optical path includes a filter wheel and a CCD. In this paper, we present the data collected from these recent campaigns, the exploitation techniques used, and the results of the analyses. The results will compare signatures from satellites in different orbit regimes under different operating conditions and illustrate the robustness of the techniques.

Payne, T.; Gregory, S.; Tombasco, J.; Luu, K.; Durr, L.

173

Layer-oriented adaptive optics for solar telescopes.  

PubMed

First multiconjugate adaptive-optical (MCAO) systems are currently being installed on solar telescopes. The aim of these systems is to increase the corrected field of view with respect to conventional adaptive optics. However, this first generation is based on a star-oriented approach, and it is then difficult to increase the size of the field of view beyond 60-80 arc sec in diameter. We propose to implement the layer-oriented approach in solar MCAO systems by use of wide-field Shack-Hartmann wavefront sensors conjugated to the strongest turbulent layers. The wavefront distortions are averaged over a wide field: the signal from distant turbulence is attenuated and the tomographic reconstruction is thus done optically. The system consists of independent correction loops, which only need to account for local turbulence: the subapertures can be enlarged and the correction frequency reduced. Most importantly, a star-oriented MCAO system becomes more complex with increasing field size, while the layer-oriented approach benefits from larger fields and will therefore be an attractive solution for the future generation of solar MCAO systems. PMID:22885589

Kellerer, Aglaé

2012-08-10

174

Design Requirements and Component Down Selection Process for an Aperture Masking Instrument at the Magdalena Ridge Observatory 2.4m Telescope  

NASA Astrophysics Data System (ADS)

The design of a new instrument requires careful consideration of all components to ensure that design specifications are met while staying within the prescribed budget. This poster presents the down selection process for the major components of a new instrument for the Magdalena Ridge Observatory 2.4m telescope. This instrument is designed primarily for aperture masking at optical wavelengths, a technique that converts a single aperture into a multi-aperture Michelson stellar interferometer. With minor modification this instrument can also be used for millimag photometry, millisecond photometry and other high speed imaging techniques. This poster includes the design requirements and decision process for three main components; the instrument structural support required to mount the instrument to the Nasmyth focus of the telescope, the optical system necessary to re-image the primary aperture, filter and mask incoming light and then produce the correct image scale on the CCD, and finally, CCD performance required to take high-frame-rate, low-noise images. This work is supported by LANL-NMT MOU UCDRD funding and the New Mexico Space Grant Consortium.

Schmidt, Luke M.; Teare, S. W.; Westpfahl, D. J.; Jurgenson, C. A.

2009-05-01

175

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

176

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

177

Hubble Space Telescope Spectrophotometry and Models for Solar Analogs  

NASA Astrophysics Data System (ADS)

Absolute flux distributions for seven solar analog stars are measured from 0.3 to 2.5 ?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 & 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 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 ~1%; and the modeled flux distributions of these G stars have an estimated ensemble accuracy of 2% out to 30 ?m.

Bohlin, R. C.

2010-04-01

178

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

179

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

180

High-contrast, Narrow-field Exoplanet Imaging with a Multi-aperture Telescope Phased-array Coronagraph  

NASA Astrophysics Data System (ADS)

The coronagraphic imaging of nearby solar systems with a densely packed array of small, inexpensive collector telescopes is considered. A reduced-scale segmented pupil can be assembled downstream of the collectors either by means of an array of delay lines, or more conveniently, by means of an array of single-mode fibers. In either case, the individual pupil elements are completely decoupled from each other. Tuning the intensity and phase of the light in each pupil element then allows complete control over the pupil-plane field, thus enabling arbitrary and tunable complex pupil-plane apodization. Calculations show that such a "phased-array coronagraph" (PAC) can in principle provide the10-10 image-plane contrast required for terrestrial exoplanet observations near bright stars. A PAC may thus provide a route to coronagraphic observations of faint exoplanets that is both flexible and potentially relatively inexpensive.

Serabyn, E.

2009-06-01

181

Overview and Recent Accomplishments of the Advanced Mirror Technology Development (AMTD) for Large Aperture UVOIR Space Telescopes Project  

NASA Technical Reports Server (NTRS)

Per Astro2010, a new, larger UVO telescope is needed to answer fundamental scientific questions, such as: is there life on Earth-like exoplanets; how galaxies assemble stellar populations; how baryonic matter interacts with intergalactic medium; and how solar systems form and evolve. And, present technology is not mature enough to affordably build and launch any potential UVO concept. Advanced Mirror Technology Development (AMTD) is a funded SAT project. Our objective is to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. One of our key accomplishments is that we have derived engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicle and its inherent mass and volume constraints. We defined and initiated a program to mature 6 key technologies required to fabricate monolithic and segmented space mirrors.

Stahl, H. Philip

2013-01-01

182

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

183

A Large Sparse Aperture Densified Pupil Hypertelescope Concept for Ground Based Detection of Extra-Solar Earth-Like Planets  

NASA Technical Reports Server (NTRS)

A concept is presented for a large (10 - 30 meter) sparse aperture hyper telescope to image extrasolar earth-like planets from the ground in the presence of atmospheric seeing. The telescope achieves high dynamic range very close to bright stellar sources with good image quality using pupil densification techniques. Active correction of the perturbed wavefront is simplified by using 36 small flat mirrors arranged in a parabolic steerable array structure, eliminating the need for large delat lines and operating at near-infrared (1 - 3 Micron) wavelengths with flats comparable in size to the seeing cells.

Gezari, D.; Lyon, R.; Woodruff, R.; Labeyrie, A.; Oegerle, William (Technical Monitor)

2002-01-01

184

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 of the Earth). The detrimental effects of solar storm induced "space weather" ranges from disruption of our. The National Oceanic & Atmospheric Administration (NOAA) and NASA are cooperating on a Solar X-ray Imager (SXI

Van Stryland, Eric

185

The Daniel K. Inouye Solar Telescope first light instruments and critical science plan  

NASA Astrophysics Data System (ADS)

The Daniel K. Inouye Solar Telescope is a 4-meter-class all-reflecting telescope under construction on Haleakal? mountain on the island of Maui, Hawai'i. When fully operational in 2019 it will be the world's largest solar telescope with wavelength coverage of 380 nm to 28 microns and advanced Adaptive Optics enabling the highest spatial resolution measurements of the solar atmosphere yet achieved. We review the first-generation DKIST instrument designs, select critical science program topics, and the operations and data handling and processing strategies to accomplish them.

Elmore, David F.; Rimmele, Thomas; Casini, Roberto; Hegwer, Steve; Kuhn, Jeff; Lin, Haosheng; McMullin, Joseph P.; Reardon, Kevin; Schmidt, Wolfgang; Tritschler, Alexandra; Wöger, Friedrich

2014-07-01

186

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

187

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

188

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.

189

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

190

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 reconnection taking place in the chromosphere is responsible for canceling magnetic features. Subject headings: Sun: magnetic topology -- Sun: chromosphere -- Sun: pho- tosphere -- magnetic reconnection

191

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

192

Point spread functions for the Solar Optical Telescope onboard Hinode  

E-print Network

The combined PSF of the BFI and the SOT onboard the Hinode spacecraft is investigated. Observations of the Mercury transit from November 2006 and the solar eclipse(s) from 2007 are used to determine the PSFs of SOT for the blue, green, and red continuum channels of the BFI. For each channel large grids of theoretical point spread functions are calculated by convolution of the ideal diffraction-limited PSF and Voigt profiles. These PSFs are applied to artificial images of an eclipse and a Mercury transit. The comparison of the resulting artificial intensity profiles across the terminator and the corresponding observed profiles yields a quality measure for each case. The optimum PSF for each observed image is indicated by the best fit. The observed images of the Mercury transit and the eclipses exhibit a clear proportional relation between the residual intensity and the overall light level in the telescope. In addition there is a anisotropic stray-light contribution. ... BFI/SOT operate close to the diffraction limit and have only a rather small stray-light contribution. The FWHM of the PSF is broadened by only ~1% with respect to the diffraction-limited case, while the overall Strehl ratio is ~ 0.8. In view of the large variations -- best seen in the residual intensities of eclipse images -- and the dependence on the overall light level and position in the FOV, a range of PSFs should be considered instead of a single PSF per wavelength. The individual PSFs of that range allow then the determination of error margins for the quantity under investigation. Nevertheless the stray-light contributions are here found to be best matched with Voigt functions with the parameters sigma = 0."008 and gamma = 0."004, 0."005, and 0."006 for the blue, green, and red continuum channels, respectively.

Sven Wedemeyer-Böhm

2008-05-07

193

Observation and Modeling of the Solar Transition Region. 1; Multi-Spectral Solar Telescope Array Observations  

NASA Technical Reports Server (NTRS)

We report on observations of the solar atmosphere in several extreme-ultraviolet and far-ultraviolet bandpasses obtained by the Multi-Spectral Solar Telescope Array, a rocket-borne spectroheliograph, on flights in 1987, 1991, and 1994, spanning the last solar maximum. Quiet-Sun emission observed in the 171-175 Angstrom bandpass, which includes lines of O v, O VI, Fe IX, and Fe X, has been analyzed to test models of the temperatures and geometries of the structures responsible for this emission. Analyses of intensity variations above the solar limb reveal scale heights consistent with a quiet-Sun plasma temperature of 500,000 less than or equal to T (sub e) less than or equal to 800,000 K. The structures responsible for the quiet-Sun EUV emission are modeled as small quasi-static loops. We submit our models to several tests. We compare the emission our models would produce in the bandpass of our telescope to the emission we have observed. We find that the emission predicted by loop models with maximum temperatures between 700,000 and 900,000 K are consistent with our observations. We also compare the absolute flux predicted by our models in a typical upper transition region line to the flux measured by previous observers. Finally, we present a preliminary comparison of the predictions of our models with diagnostic spectral line ratios from previous observers. Intensity modulations in the quiet Sun are observed to occur on a scale comparable to the supergranular scale. We discuss the implications that a distribution of loops of the type we model here would have for heating the local network at the loops' footpoints.

Oluseyi, Hakeem M.; Walker, A. B. C., II; Porter, Jason; Hoover, Richard B.; Barbee, Troy W., Jr.

1999-01-01

194

Long-range Plans for the NASA Infrared Telescope Facility  

Microsoft Academic Search

The NASA Infrared Telescope Facility (IRTF) is a 3-meter optical\\/IR telescope dedicated to NASA-related programs of mission support and basic solar system research. All of the funding for IRTF operations comes from the Planetary Astronomy Program. The IRTF is unique in providing NASA with a dedicated telescope for mission support. Its aperture is sufficient for many kinds of solar system

A. T. Tokunaga; S. J. Bus; J. Rayner; E. V. Tollestrup

2004-01-01

195

Turbulent kinetic energy spectra of solar convection from New Solar Telescope observations and realistic magnetohydrodynamic simulations  

NASA Astrophysics Data System (ADS)

Turbulent properties of the quiet Sun represent the basic state of surface conditions and a background for various processes of solar activity. Therefore, understanding the properties and dynamics of this ‘basic’ state is important for the investigation of more complex phenomena, the formation and development of observed phenomena in the photosphere and atmosphere. For the characterization of turbulent properties, we compare the kinetic energy spectra on granular and sub-granular scales obtained from infrared TiO observations with the New Solar Telescope (Big Bear Solar Observatory) and from three-dimensional radiative magnetohydrodynamic (MHD) numerical simulations (‘SolarBox’ code). We find that the numerical simulations require high spatial resolution with a 10-25 km grid step in order to reproduce the inertial (Kolmogorov) turbulence range. The observational data require an averaging procedure to remove noise and potential instrumental artifacts. The resulting kinetic energy spectra reveal good agreement between the simulations and the observations, opening up new perspectives for detailed joint analyses of more complex turbulent phenomena on the Sun and possibly on other stars. In addition, using the simulations and observations, we investigate the effects of a background magnetic field, which is concentrated in self-organized complicated structures in intergranular lanes, and observe an increase of the small-scale turbulence energy and its decrease at larger scales due to magnetic field effects.

Kitiashvili, I. N.; Abramenko, V. I.; Goode, P. R.; Kosovichev, A. G.; Lele, S. K.; Mansour, N. N.; Wray, A. A.; Yurchyshyn, V. B.

2013-07-01

196

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

197

Fast Imaging Solar Spectrograph of the 1.6 Meter New Solar Telescope at Big Bear Solar Observatory  

NASA Astrophysics Data System (ADS)

For high resolution spectral observations of the Sun - particularly its chromosphere, we have developed a dual-band echelle spectrograph named Fast Imaging Solar Spectrograph (FISS), and installed it in a vertical optical table in the Coudé Lab of the 1.6 meter New Solar Telescope at Big Bear Solar Observatory. This instrument can cover any part of the visible and near-infrared spectrum, but it usually records the H? band and the Ca ii 8542 Å band simultaneously using two CCD cameras, producing data well suited for the study of the structure and dynamics of the chromosphere and filaments/prominences. The instrument does imaging of high quality using a fast scan of the slit across the field of view with the aid of adaptive optics. We describe its design, specifics, and performance as well as data processing

Chae, Jongchul; Park, Hyung-Min; Ahn, Kwangsu; Yang, Heesu; Park, Young-Deuk; Nah, Jakyoung; Jang, Bi Ho; Cho, Kyung-Suk; Cao, Wenda; Goode, Philip R.

2013-11-01

198

A new controlling system for the solar tower telescope of IZMIRAN: II. A solar image motion compensator  

Microsoft Academic Search

A solar image motion compensator for the solar tower telescope is described. Two mutually perpendicular CCD linear arrays\\u000a are used as photodetectors. An algorithm for forecasting the system behavior is used for generation of correction signals.\\u000a Analyzing the solar image motion data obtained using the compensator and without it has shown that, thanks to its use, the\\u000a total image motion

I. E. Kozhevatov; E. A. Rudenchik; N. P. Cheragin; B. A. Ioshpa; E. Kh. Kulikova; E. G. Bezrukova

2000-01-01

199

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

E-print Network

The Thermal Control of the New Solar Telescope at Big Bear Observatory Angelo P. Verdonia and Carsten Denkera aNew Jersey Institute of Technology, Center for Solar-Terrestrial Research, 323 Martin Luther King Blvd, Newark, NJ 07102, US ABSTRACT We present the basic design of the THermal Control System

200

Filters for soft X-ray solar telescopes  

NASA Technical Reports Server (NTRS)

Soft X-ray telescopes require filters that block visible and infrared light and have good soft X-ray transmission. The optical properties of possible materials are discussed, and the fabrication and testing methods for the filters used in a 10-inch normal incidence telescope for 63 A are described. The best performances in the 44-114-A wavelength range are obtained with foils of carbon and rhodium.

Spiller, Eberhard; Grebe, Kurt; Golub, Leon

1990-01-01

201

Multi Application Solar Telescope (MAST): A Versatile Tool for Studying the Physics of Solar Eruptions  

NASA Astrophysics Data System (ADS)

pvk@prl.res.in Contemporary solar research is progressing along several fronts. Solar magnetism and its role in powering solar eruptions is one basic theme. Quantitative evaluation of the different manifestations of the free energy available for eruption is one major task. This requires vector magnetograms of a large number of active regions monitored closely in time with high polarimetric accuracy. The second task is to obtain greater clarity about various triggering mechanisms for the eruptions. This requires observations of line-of-sight magnetic fields and velocity fields with high spatial resolution. Both tasks need mutually exclusive requirements leading to the concept of the multi application telescope. In this talk, I outline the various steps, like site characterization, optical design, adaptive optics development and schemes for back-end instrumentation that culminated in the present concept of MAST. I will emphasize the constraints posed by availability of and access to technology which played a significant role in deciding the concept. I conclude by highlighting certain unique features of MAST which can provide special insights into a few scientific problems.

Venkatakrishnan, P.

2006-11-01

202

Application of a white-light interferometric measuring system as co-phasing the segmented primary mirrors of the high-aperture telescope  

NASA Astrophysics Data System (ADS)

For the optical system of the telescope, with the increase in telescope size, the manufacture of monolithic primary becomes increasingly difficult. Instead, the use of segmented mirrors, where many individual mirrors (the segments) work together to provide an image quality and an aperture equivalent to that of a large monolithic mirror, is considered a more appropriate strategy. But with the introduction of the large telescope mirror comprised of many individual segments, the problem of insuring a smooth continuous mirror surface (co-phased mirrors) becomes critical. One of the main problems is the measurement of the vertical displacement between the individual segments (piston error), for such mirrors, the segment vertical misalignment (piston error) between the segments must be reduced to a small fraction of the wavelength (<100nm) of the incoming light. The measurements become especially complicated when the piston error is in order of wavelength fractions. To meet the performance capabilities, a novel method for phasing the segmented mirrors optics system is described. The phasing method is based on a high-aperture Michelson interferometer. The use of an interferometric technique allows the measuring of segment misalignment during the daytime with high accuracy, which is a major design guideline. The innovation introduced in the optical design of the interferometer is the simultaneous use of monochromatic light and multiwavelength combination white-light source in a direct method for improving the central fringe identification in the white-light interferometric phasing system. With theoretic analysis, we find that this multiwavelength combination technique can greatly increase the visibility difference between the central fringe and its adjacent side fringes, and thus it offers an increased signal resolution. So make the central fringe identification become easier, and enhance the measure precision of the segment phasing error. Consequently, it is suitable for high-precision measurement purpose and application in the segment piston error phasing system. The description about the expected interferograms and the feasibility of the phasing method are presented here.

Song, Helun; Li, Huaqiang; Xian, Hao; Huang, Jian; Wang, Shengqian; Jiang, Wenhan

2008-03-01

203

Review of the Solar Array Telescopes David A. Smith  

E-print Network

that of the Cherenkov imaging tele- scopes have been the "solar tower" detectors. They use > 2000 m2 mirror areas than 6 in one ON-source hour. I will review the history of the solar tower Cherenkov experiments from, solar tower facilities were built in several countries to generate electricity, or as high temperature

Paris-Sud XI, Université de

204

The Galactic Exoplanet Survey Telescope: A Proposed Space-Based Microlensing Survey for Terrestrial Extra-Solar Planets  

E-print Network

We present a conceptual design for a space based Galactic Exoplanet Survey Telescope (GEST) which will use the gravitational microlensing technique to detect extra solar planets with masses as low as that of Mars at all separations >~ 1 AU. The microlensing data would be collected by a diffraction limited, wide field imaging telescope of ~ 1.5m aperture equipped with a large array of red-optimized CCD detectors. Such a system would be able to monitor $\\sim 2\\times 10^8$ stars in $\\sim 6$ square degrees of the Galactic bulge at intervals of 20-30 minutes, and it would observe $\\sim 12000$ microlensing events in three bulge seasons. If planetary systems like our own are common, GEST should be able to detect $\\sim 5000$ planets over a 2.5 year lifetime. If gas giants like Jupiter and Saturn are rare, then GEST would detect $\\sim 1300$ planets in a 2.5 year mission if we assume that most planetary systems are dominated by planets of about Neptune's' mass. Such a mission would also discover $\\sim 100$ planets of an Earth mass or smaller if such planets are common. This is a factor of $\\sim 50$ better than the most ambitious ground based programs that have been proposed. GEST will also be sensitive to planets which have been separated from their parent stars.

David P. Bennett; Sun Hong Rhie

2000-03-08

205

Optomechanical and thermal design of the Multi-Application Solar Telescope for USO  

NASA Astrophysics Data System (ADS)

The Multi-Application Solar Telescope (MAST) is a 50 cm diameter class telescope to be installed on the Udaipur Solar Observatory's Island on the Lake Fatehsagar in Udaipur, India. It is dedicated to solar observation. The telescope is designed, manufactured, assembled and installed on-site by the belgian company AMOS SA for the Udaipur Solar Observatory (USO), an academic division of the Physical Research Laboratory (PRL) in India. Despite its limited size, the telescope is expected to be competitive with respect to worldwide large and costly projects thanks to its versatility regarding science goals and also thanks to its demanding optomechanical and thermal specification. This paper describes the optomechanical and thermal design of this telescope and presents solutions adopted by AMOS to meet the specific requirements. The optical configuration of the telescope is based on an afocal off-axis gregorian combination integrated on an Alt.-Az. mechanical mount, with a suite of flat folding mirrors to provide the required stationary collimated beam.

Denis, Stefan; Coucke, Pierre; Gabriel, Eric; Delrez, Christophe; Venkatakrishnan, Parameshwaran

2008-07-01

206

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

Microsoft Academic Search

The solar neutron telescope (SNT) at Sierra Negra (19.0°N, 97.3°W and 4580m.a.s.l) is part of a worldwide network of similar detectors (Valdés-Galicia et al., (2004) [1]). This SNT has an area of 4m2; it is composed by four 1m×1m×30cm plastic scintillators (Sci). The Telescope is completely surrounded by anti-coincidence proportional counters (PRCs) to separate charged particles from the neutron flux.

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

2010-01-01

207

Single aperture imaging astrometry with a diffracting pupil: application to exoplanet mass measurement with a small coronagraphic space telescope  

NASA Astrophysics Data System (ADS)

High precision astrometry of nearby bright stars is theoretically (in the photon noise limit) possible with a space coronagraph using a wide field diffraction limited camera imaging an annulus of background stars around the central coronagraphic field. With the sub-micro arcsecond accuracy theoretically achievable on a 1.4-m telescope, the mass of all planets that can be imaged by the coronagraph would be estimated. Simultaneous imaging and astrometric measurements would reduce the number of astrometric measurements necessary for mass determination, and reduce confusion between multiple planets and possible exozodiacal clouds in the coronagraphic image. While scientifically attractive, this measurement is technically very challenging, and must overcome astrometric distortions, which, in conventional telescopes, are several orders of magnitude above the photon noise limit. In this paper, we propose a new approach to calibrating astrometric distortions in the wide field imaging camera. The astrometric measurement is performed by simultaneously imaging background stars and diffraction spikes from the much brighter coronagraphic target on the same focal plane array. The diffraction spikes are generated by a series of small dark spots on the primary mirror to reduce sensitivity to optical and mechanical distortions. Small scale distortions and detector errors are averaged down to sub-micro arcsecond by rolling the telescope around the line of sight. A preliminary error budget is shown and discussed to identify major sources of error for a 1.4-m telescope imaging a 0.25 squaredeg field of view at the galactic pole.

Guyon, Olivier; Shao, Michael; Shaklan, Stuart; Levine, Marie; Ammons, Mark; Bendek, Eduardo; Woodruff, Robert; Nemati, Bijan; Pitman, Joe

2010-07-01

208

Telescopes  

NSDL National Science Digital Library

Authored by Nick Strobel, "Astronomy Notes" is an educational resource for introductory astronomy classes for undergraduates. This section discusses refracting, reflecting, and radio telescopes. Definitions and properties of light-gathering power, resolving power, and magnifying power are also included. This is a nice resource for instructors looking to enhance their astronomy curriculum.

Strobel, Nick

209

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

210

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

211

A new controlling system for the solar tower telescope of IZMIRAN: I. Guide  

Microsoft Academic Search

A new guiding system for the solar tower telescope is described. Two mutually perpendicular CCD arrays are used as photodetectors.\\u000a The guide provides a positional error of no larger than 0.2? in a frequency band of 0–10 Hz. The software allows for referring\\u000a the spectrograph slit position to solar coordinate systems and provides for various guide operation modes.

I. E. Kozhevatov; E. A. Rudenchik; N. P. Cheragin; B. A. Ioshpa; E. Kh. Kulikova; E. G. Bezrukova

2000-01-01

212

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

213

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

214

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

215

PET: a proton\\/electron telescope for studies of magnetospheric, solar, and galactic particles  

Microsoft Academic Search

The proton\\/electron telescope (PET) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide measurements of energetic electrons and light nuclei from solar, Galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from ~1 to ~30 MeV and H and He nuclei from ~20 to ~300 MeV\\/nucleon, with

W. R. Cook; A. C. Cummings; J. R. Cummings; T. L. Garrard; B. Kecman; R. A. Mewaldt; R. S. Selesnick; E. C. Stone; D. N. Baker; T. T. von Rosenvinge; J. B. Blake; L. B. Callis

1993-01-01

216

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

217

OpTIIX: An ISS-Based Testbed Paving the Roadmap Toward a Next Generation Large Aperture UV/Optical Space Telescope  

NASA Technical Reports Server (NTRS)

The next generation large aperture UV/Optical space telescope will need a diameter substantially larger than even that of JWST in order to address some of the most compelling unanswered scientific quests. These quests include understanding the earliest phases of the Universe and detecting life on exo-planets by studying spectra of their atmospheres. Such 8-16 meter telescopes face severe challenges in terms of cost and complexity and are unlikely to be affordable unless a new paradigm is adopted for their design and construction. The conventional approach is to use monolithic or preassembled segmented mirrors requiring complicated and risky deployments and relying on future heavy-lift vehicles, large fairings and complex geometry. The new paradigm is to launch component modules on relatively small vehicles and then perform in-orbit robotic assembly of those modules. The Optical Testbed and Integration on ISS eXperiment (OpTIIX) is designed to demonstrate, at low cost by leveraging the infrastructure provided by ISS, telescope assembly technologies and end-to-end optical system technologies. The use of ISS as a testbed permits the concentration of resources on reducing the technical risks associated with robotically integrating the components. These include laser metrology and wavefront sensing and control (WFS&C) systems, an imaging instrument, lightweight, low-cost deformable primary mirror segments and the secondary mirror. These elements are then aligned to a diffraction-limited optical system in space. The capability to assemble the optical system and remove and replace components via the existing ISS robotic systems like the Special Purpose Dexterous Manipulator (SPDM), or by the ISS flight crew, allows for future experimentation, as well as repair.

Carpenter, Kenneth G.; Etemad, Shar; Seery, Bernard D.; Thronson, Harley; Burdick, Gary M.; Coulter, Dan; Goullioud, Renaud; Green, Joseph J.; Liu, Fengchuan; Ess, Kim; Postman, Marc; Sparks, Williams

2012-01-01

218

Solar Polar ORbit Telescope (SPORT): A Potential Heliophysics Mission of China  

NASA Astrophysics Data System (ADS)

We describe a spacecraft mission, named Solar Polar ORbit Telescope (SPORT), which is currently under a scientific and engineering background study in China. SPORT was originally proposed in 2004 by the National Space Science Center, Chinese Academy of Sciences. It will carry a suite of remote-sensing and in-situ instruments to observe coronal mass ejections (CMEs), solar high-latitude magnetism, and the fast solar wind from a polar orbit around the Sun. It is intended to be the first mission that carries remote-sensing instruments from a high-latitude orbit around the Sun and the first mission that could measure solar high-latitude magnetism. The first extended view of the polar region of the Sun and the ecliptic plane enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere and solar high-latitude magnetism giving rise to eruptions and the fast solar wind.

Liu, Ying

219

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

220

Experimental study of natural convection heat transfer through an aperture in passive solar heated buildings  

SciTech Connect

The objective of this study is to obtain correlations between natural convection heat transfer through an aperture and temperature difference between the two rooms. A one-fifth similitude model of a two-room building is used. The model is filled with Freon gas to satisfy similarity of the experiment to full-scale conditions in air. The experimental apparatus and experimental techniques are explained. Experimental results are presented in terms of Grashof, Nusselt, and Prandtl numbers. The effects of the height, the width, and the vertical position of the apertures are investigated, as is the effect of the room volume.

Yamaguchi, Kenjiro

1984-01-01

221

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

222

The CERN Axion Solar Telescope (CAST): status and prospects  

Microsoft Academic Search

The CAST experiment is being mounted at CERN. It will make use of a decommissioned LHC test magnet to look for solar axions through its conversion into photons inside the magnetic field. The magnet has a field of 9 Tesla and length of 10 m and is installed in a platform which allows to move it ~8 degrees vertically and

S. ANDRIAMONJE; E. ARIK; D. AUTIERO; F. AVIGNONE; K. BARTH; E. BINGOL; H. BRAUNINGER; R. BRODZINSKI; J. CARMONA; E. CHESI; S. CEBRIAN; S. CETIN; J. COLLAR; R. CRESWICK; T. DAFNI; R. DE OLIVEIRA; S. DEDOUSSIS; A. DELBART; L. DI LELLA; C. ELEFTHERIADIS; G. FANOURAKIS; H. FARACH; H. FISCHER; F. FORMENTI; T. GERALIS; I. GIOMATARIS; S. GNINENKO; N. GOLOUBEV; R. HARTMANN; M. HASINOFF; D. HOFFMANN; J. JACOBY; D. KANG; R. KOTTHAUS; M. KRCMAR; M. KUSTER; B. LAKIC; A. LIOLIOS; A. LJUBICIC; G. LUTZ; G. LUZON; H. MILEY; A. MORALES; J. MORALES; M. MUTTERER; A. NIKOLAIDIS; A. ORTIZ; T. PAPAEVANGELOU; A. PLACCI; G. RAFFELT; H. RIEGE; M. SARSA; I. SAVVIDIS; R. SCHOPPER; I. SEMERTZIDIS; C. SPANO; J. VILLAR; B. VULLIERME; L. WALCKIERS; K. ZACHARIADOU; K. ZIOUTAS

2002-01-01

223

The CERN Axion Solar Telescope (cast):. Status and Prospects  

Microsoft Academic Search

The CAST experiment is being mounted at CERN. It will make use of a decommissioned LHC test magnet to look for solar axions through its conversion into photons inside the magnetic field. The magnet has a field of 9 Tesla and length of 10 m and is installed in a platform which allows to move it ±8° vertically and ±40°

I. G. Irastorza; S. Andriamonje; E. Arik; D. Autiero; F. Avignone; K. Barth; E. Bingol; H. Bräuninger; R. Brodzinski; J. Carmona; E. Chesi; S. Cebrian; S. Cetin; J. Collar; R. Creswick; T. Dafni; R. de Oliveira; S. Dedoussis; A. Delbart; L. di Lella; C. Eleftheriadis; G. Fanourakis; H. Farach; H. Fischer; F. Formenti; T. Geralis; I. Giomataris; S. Gninenko; N. Goloubev; R. Hartmann; M. Hasinoff; D. Hoffmann; J. Jacoby; D. Kang; K. Königsmann; R. Kotthaus; M. Krcmar; M. Kuster; B. Lakic; A. Liolios; A. Ljubicic; G. Lutz; G. Luzon; H. Miley; A. Morales; J. Morales; M. Mutterer; A. Nikolaidis; A. Ortiz; T. Papaevangelou; A. Placci; G. Raffelt; H. Riege; M. Sarsa; I. Savvidis; J. Schopper; I. Semertzidis; C. Spano; J. Villar; B. Vullierme; L. Walckiers; K. Zachariadou; K. Zioutas

2003-01-01

224

The CERN axion solar telescope (CAST): status and prospects  

Microsoft Academic Search

The CAST experiment is being mounted at CERN. It will make use of a decommissioned LHC test magnet to look for solar axions through its conversion into photons inside the magnetic field. The magnet has a field of 9.6 Tesla and length of 10 m and is installed in a platform which allows to move it ±8° vertically and ±40°

I. G. Irastorza; S. Andriamonje; E. Arik; D. Autiero; F. Avignone; K. Barth; H. Brauninger; R. Brodzinski; J. Carmona; S. Cebrian; S. Cetin; J. Collar; R. Creswick; R. De Oliveira; A. Delbart; L. Di Lella; C. Eleftheriadis; G. Fanourskis; H. Farach; H. Fischer; F. Formenti; T. Geralis; I. Giomataris; S. Gninenko; N. Goloubev; R. Hartmann; M. Hasinoff; D. Hoffmann; J. Jacoby; D. Kang; K. Konigsmann; R. Kotthaus; M. Krcmar; M. Kuster; B. Lakic; A. Liolios; A. Ljubicic; G. Lutz; G. Luzon; H. Miley; A. Morales; J. Morales; M. Mutterer; A. Nikolaidis; A. Ortiz; T. Papaevangelou; A. Placci; G. Raffelt; H. Riege; M. Sarsa; I. Savvidis; C. Spano; J. Villar; B. Vullierme; L. Walckiers; K. Zachariadou; K. Zioutas

2003-01-01

225

THz solar telescope for detection flare synchrotron radiation  

Microsoft Academic Search

Recent solar flare observations have shown the existence of a spectral component exhibiting fluxes increasing with frequency in the sub-THz spectrum simultaneously with the well known spectral component peaking at microwaves bringing challenging constraints for interpretation. This double spectral feature cannot be well explained by existing models. One possibility is to associate the high frequency emissions to incoherent synchrotron radiation

Pierre Kaufmann; J. Michael Klopf

2011-01-01

226

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

227

Solar EUV, XUV and soft X-ray telescope facilities  

NASA Technical Reports Server (NTRS)

Facility class, high resolution instrumentation can enable maximum spatial, spectral and temporal resolutions and provide understanding of the complex physical conditions in the outer solar atmosphere and the mechanisms responsible for these conditions. The scientific rationale for facility class instruments operating in the EUV, XUV, and soft X ray spectral ranges are discussed. Possible configurations for these facilities and priorities for their development are considered.

Withbroe, G. L.

1982-01-01

228

EIT: Solar corona synoptic observations from SOHO with an Extreme-ultraviolet Imaging Telescope  

NASA Technical Reports Server (NTRS)

The Extreme-ultraviolet Imaging Telescope (EIT) of SOHO (solar and heliospheric observatory) will provide full disk images in emission lines formed at temperatures that map solar structures ranging from the chromospheric network to the hot magnetically confined plasma in the corona. Images in four narrow bandpasses will be obtained using normal incidence multilayered optics deposited on quadrants of a Ritchey-Chretien telescope. The EIT is capable of providing a uniform one arc second resolution over its entire 50 by 50 arc min field of view. Data from the EIT will be extremely valuable for identifying and interpreting the spatial and temperature fine structures of the solar atmosphere. Temporal analysis will provide information on the stability of these structures and identify dynamical processes. EIT images, issued daily, will provide the global corona context for aid in unifying the investigations and in forming the observing plans for SOHO coronal instruments.

Delaboudiniere, J. P.; Gabriel, A. H.; Artzner, G. E.; Michels, D. J.; Dere, K. P.; Howard, R. A.; Catura, R.; Stern, R.; Lemen, J.; Neupert, W.

1988-01-01

229

Fermi Large Area Telescope observations of high-energy gamma-ray emission from solar flares  

NASA Astrophysics Data System (ADS)

With the current solar cycle reaching its maximum, the Fermi observatory has proven to play an active role in the study of solar flares. The Large Area Telescope (LAT) on-board Fermi has detected >30 MeV gamma-ray emission associated with GOES M-class and X-class X-ray flares accompanied by coronal mass ejections and solar energetic particle events. These detections include both the impulsive and the long duration phases including the ~20 hours of extended emission from the 2012 March 7 X-class flares. Accurate localization with the Fermi LAT of the gamma-ray production site(s) coincide with the solar active region from which X-ray emissions associated with the 2012 March 7 X-class flares originated. In this talk I present an overview of the Fermi solar flare detections over the past five years of operation.

Pesce-Rollins, Melissa; Omodei, N.; Petrosian, V.; Fermi LAT Collaboration

2014-01-01

230

An updated 37-element low-order solar adaptive optics system for 1-m new vacuum solar telescope at Full-Shine Lake Solar Observatory  

NASA Astrophysics Data System (ADS)

A low-order solar adaptive optics (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 37-element deformable mirror, a correlating Shack-Hartmann wavefront sensor and a high-order wavefront correction controller, had been successfully developed and installed at 1-m New Vacuum Solar Telescope of Full-shine Lake (also called Fuxian Lake) Solar Observatory. This system is an update of the 37-element solar AO system designed for the 26-cm Solar Fine Structure Telescope at Yunnan Astronomical Observatory in 2009. The arrangement of subapertures of the Shack-Hartmann wavefront sensor was changed from square to hexagon to achieve better compensation performance. Moreover, the imaging channel of the updated system was designed to observe the Sun at 710nm and 1555nm simultaneously. The AO system was integrated into the solar telescope in 2011, and AO-corrected high resolution sunspots and granulation images were obtained. The observational results show that the contrast and resolution of the solar images are improved evidently after the correction by the AO system.

Rao, Changhui; Zhu, Lei; Gu, Naiting; Rao, Xuejun; Zhang, Lanqiang; Guan, Chunlin; Chen, Donghong; Chen, Shanqiu; Wang, Cheng; Lin, Jun; Liu, Zhong

2012-07-01

231

Concept study of an Extremely Large Hyper Telescope (ELHyT) with 1200m sparse aperture for direct imaging at 100 micro-arcsecond resolution  

NASA Astrophysics Data System (ADS)

The hypertelescope construction initiated in the Southern Alps (Labeyrie et al., this conference) has provided some preliminary operating experience indicating that larger versions, up to perhaps 1200m, are probably feasible at suitable sites. The Arecibo-like architecture of such instruments does not require the large mount and dome which dominate the cost of a 40m ELT. For the same cost, an "Extremely Large Hyper Telescope” ( ELHyT) may therefore have a larger collecting area. It may thus in principle reach higher limiting magnitudes, both for seeing-limited and, if equipped with a Laser Guide Star and adaptive phasing, for high-resolution imaging with gain as the size ratio, i.e. about 30 with respect to a 40m ELT. Like the radio arrays of antennas, such instruments can be grown progressively. Also, they can be up-graded with several focal gondolas, independently tracking different sources. Candidate sites have been identified in the Himalaya and the Andes. We describe several design options and compare the science achievable for both instruments, ELTs and ELHyTs. The broad science addressed by an ELHyT covers stellar chromospheres, transiting exoplanets and those requiring a high dynamic range, achieved by array apodization or coronagraphy. With a Laser Guide Star, it extends to faint compact sources beyond the limits of telescopes having a smaller collecting area, supernovae, active galactic nuclei, gamma ray bursts. The sparse content of remote galaxies seen in the Hubble Deep Field appears compatible with the crowding limitations of an ELHyT having 1000 apertures.

Labeyrie, Antoine; Mourard, Denis; Allouche, Fatmé; Chakraborthy, Rijuparna; Dejonghe, Julien; Surya, Arun; Bresson, Yves; Aime, Claude; Mary, David; Carlotti, Alexis

2012-07-01

232

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

233

A New 0.5m Telescope (MAST) for Solar Imaging and Polarimetry  

NASA Astrophysics Data System (ADS)

In this article we discuss the design of a new 0.5 m telescope which will be installed at the lake site of Udaipur Solar Observatory (USO), India in the first quarter of 2009. The telescope has an off-axis alt-azimuth design, which will provide a low scattered-light performance. The complete telescope including the control system will be made by AMOS, Belgium. The prototype adaptive-optics system for seeing correction is being developed at USO. The design of two back-end instruments, an echelle-scanning spectrograph capable of observing simultaneously in at least two spectral lines, and an imaging spectrometer based on double Fabry-Pérot etalon, and a polarimeter common for both the instruments is in progress. The scientific objectives, design aspects and the current status of the above instruments is discussed in this paper.

Mathew, S. K.

2009-06-01

234

To appear in: "The Solar Cycle and Terrestrial Climate", Ed. A. Wilson, Procs. SOLSPA Euroconference Tenerife, ESA SP463. SOLAR MAGNETOMETRY WITH THE DUTCH OPEN TELESCOPE  

E-print Network

because many of its key problems are dominated by magnetism while the solar mag- netic field is structured Euroconference Tenerife, ESA SP­463. SOLAR MAGNETOMETRY WITH THE DUTCH OPEN TELESCOPE R.J. Rutten, R for tomographic high-resolution imaging of the magnetic topology of the solar atmosphere up to the transition

Rutten, Rob

235

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 magnitude of the disturbances was considerably larger than the design jitter requirement. 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, Carlton L.; Tinker, Michael L.; Nurre, Gerald S.; Till, William A.

1995-01-01

236

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

237

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

238

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

239

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

240

PET - A proton\\/electron telescope for studies of magnetospheric, solar, and galactic particles  

Microsoft Academic Search

The Proton\\/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from about 1 to about 30 MeV and H and He nuclei from about 20 to about 300 MeV\\/nuc, with isotope resolution

Walter R. Cook; Alan C. Cummings; Jay R. Cummings; Thomas L. Garrard; Branislav Kecman; Richard A. Mewaldt; Richard S. Selesnick; Edward C. Stone; Daniel N. Baker; Tycho T. von Rosenvinge

1993-01-01

241

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

2008-03-29

242

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

243

Development of ephemeris support in observations of distant radio sources and solar system objects at RATAN-600 radio telescope  

NASA Astrophysics Data System (ADS)

New elements of the algorithmic and software bases of the ephemeris support for the RATAN-600 radio telescope observations of distant radio sources and objects of the Solar system are briefly described.

Korzhavin, A. N.; L'vov, V. N.; Tokhchukova, S. Kh.; Tsekmeister, S. D.

2012-04-01

244

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

E-print Network

the telescope and the enclosure. It needs a certain height to minimize daytime ground turbulence. At the bottomThe pier and building of the European Solar Telescope (EST) F.C.M. Bettonvil*a , R. Codinab , A Llanoc , J.W. Pelserd , G. Sliepena a Astronomical Institute, Utrecht University Princetonplein NL-3584CC

Rutten, Rob

245

Distributed aperture synthesis.  

PubMed

Distributed aperture synthesis is an exciting technique for recovering high-resolution images from an array of small telescopes. Such a system requires optical field values measured at individual apertures to be phased together so that a single, high-resolution image can be synthesized. This paper describes the application of sharpness metrics to the process of phasing multiple coherent imaging systems into a single high-resolution system. Furthermore, this paper will discuss hardware and present the results of simulations and experiments which will illustrate how aperture synthesis is performed. PMID:20588888

Rabb, David; Jameson, Douglas; Stokes, Andrew; Stafford, Jason

2010-05-10

246

Solar Polar ORbit Telescope (SPORT): A Potential Space Weather Mission of China  

NASA Astrophysics Data System (ADS)

We describe a spacecraft mission, named Solar Polar ORbit Telescope (SPORT), which is currently under a scientific and engineering background study in China. SPORT was originally proposed in 2004 by the National Space Science Center, Chinese Academy of Sciences. It will carry a suite of remote-sensing and in-situ instruments to observe coronal mass ejections (CMEs), solar high-latitude magnetism, and the fast solar wind from a polar orbit around the Sun. It is intended to be the first mission that carries remote-sensing instruments from a high-latitude orbit around the Sun, the first mission that could image interplanetary CMEs at radio wavelengths from space, and the first mission that could measure solar high-latitude magnetism leading to eruptions and the fast solar wind. The first extended view of the polar region of the Sun and the ecliptic plane enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere and solar high-latitude magnetism giving rise to eruptions and the fast solar wind.

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

2013-12-01

247

A long duration balloon-borne telescope for solar gamma-ray astronomy  

NASA Technical Reports Server (NTRS)

A new solar gamma-ray telescope is described which is intended to take advantage of current long-duration ballon facilities such as the RACOON system. The primary scientific objective is to detect and measure gamma-ray lines from solar flares, along with the associated low-energy continuum. The proposed instrument is centered on a multiheaded Ge system and is designed to operate over the energy range 50 keV to 200 200 MeV. In the nuclear transition energy region, the average energy resolution of the primary detectors is over 20 times better than that achieved with the gamma-ray spectrometer on the Solar Maximum Mission satellite.

Owens, Alan; Chupp, Edward L.; Dunphy, Philip P.

1989-01-01

248

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

249

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

250

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

251

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

252

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

253

MAST - A mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei  

Microsoft Academic Search

The Mass Spectrometer Telescope (MAST) on SAMPEX is designed to provide high resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z = 2 to 28) over the energy range from about 10 to several hundred MeV\\/nuc. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition

Walter R. Cook; Alan C. Cummings; Jay R. Cummings; Thomas L. Garrard; Branislav Kecman; Richard A. Mewaldt; Richard S. Selesnick; Edward C. Stone; T. T. von Rosenvinge

1993-01-01

254

Sub-arcsecond Structure and Dynamics of Flare Ribbons Observed with New Solar Telescope  

NASA Astrophysics Data System (ADS)

Emission of solar flares across the electromagnetic spectrum is often observed in the form of two expanding ribbons. The standard flare model explains the flare ribbons as footpoints of magnetic arcades, emitting due to the interaction of energetic particles with the chromospheric plasma. However, the physics of this interaction and properties of the accelerated particles are still unknown. We present results of multiwavelength observations of C2.1 flare of August 15, 2011, observed with the 1.6-meter New Solar Telescope of Big Bear Solar Observatory. These unique data are characterized by the great spatial resolution reaching the telescope diffraction limit with good spectral scanning of H-alpha line, and photospheric imaging. The observations reveal previously unresolved sub-arcsecond structure of the flare ribbons in regions of strong magnetic field. We discuss the fine structure of the flare ribbons, their dynamics, and possible mechanisms of the energy release and transport, using also data from SDO, GOES and FERMI spacecraft.

Sharykin, Ivan; Kosovichev, Alexander G.

2014-06-01

255

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

256

Solar dynamic modules for Space Station Freedom: The relationship between fine-pointing control and thermal loading of the aperture plate  

NASA Technical Reports Server (NTRS)

Dynamic simulations of Space Station Freedom (SSF) configured with solar dynamic (SD) power modules were performed. The structure was subjected to Space Shuttle docking disturbances, while being controlled with a 'natural' vibration and tracking control approach. Three control cases were investigated for the purpose of investigating the relationship between actuator effort, SD pointing, and thermal loading on the receiver aperture plate. Transient, one-dimensional heat transfer analyses were performed to conservatively predict temperatures of the multi-layered receiver aperture plate assembly and thermal stresses in its shield layer. Results indicate that the proposed aperture plate is tolerant of concentrated flux impingement during short-lived structural disturbances. Pointing requirements may be loosened and the requirement control torques lessened from that previously specified. Downsizing and simplifying the joint drive system should result in a considerable savings mass.

Quinn, Roger D.; Kerslake, Thomas W.

1992-01-01

257

The Thermal Environment of the Fiber Glass Dome for the New Solar Telescope at Big Bear Solar Observatory  

E-print Network

The New Solar Telescope (NST) is a 1.6-meter off-axis Gregory-type telescope with an equatorial mount and an open optical support structure. To mitigate the temperature fluctuations along the exposed optical path, the effects of local/dome-related seeing have to be minimized. To accomplish this, NST will be housed in a 5/8-sphere fiberglass dome that is outfitted with 14 active vents evenly spaced around its perimeter. The 14 vents house louvers that open and close independently of one another to regulate and direct the passage of air through the dome. In January 2006, 16 thermal probes were installed throughout the dome and the temperature distribution was measured. The measurements confirmed the existence of a strong thermal gradient on the order of 5 degree Celsius inside the dome. In December 2006, a second set of temperature measurements were made using different louver configurations. In this study, we present the results of these measurements along with their integration into the thermal control system (ThCS) and the overall telescope control system (TCS).

A. P. Verdoni; C. Denker; J. R. Varsik; S. Shumko; J. Nenow; R. Coulter

2007-08-04

258

Advanced Scintillator-Based Compton Telescope for Solar Flare Gamma-Ray Measurements  

NASA Astrophysics Data System (ADS)

A major goal of future Solar and Heliospheric Physics missions is the understanding of the particle acceleration processes taking place on the Sun. Achieving this understanding will require detailed study of the gamma-ray emission lines generated by accelerated ions in solar flares. Specifically, it will be necessary to study gamma-ray line ratios over a wide range of flare intensities, down to small C-class flares. Making such measurements over such a wide dynamic range, however, is a serious challenge to gamma-ray instrumentation, which must deal with large backgrounds for faint flares and huge counting rates for bright flares. A fast scintillator-based Compton telescope is a promising solution to this instrumentation challenge. The sensitivity of Compton telescopes to solar flare gamma rays has already been demonstrated by COMPTEL, which was able to detect nuclear emission from a C4 flare, the faintest such detection to date. Modern fast scintillators, such as LaBr3, and CeBr3, are efficient at stopping MeV gamma rays, have sufficient energy resolution (4% or better above 0.5 MeV) to resolve nuclear lines, and are fast enough (~15 ns decay times) to record at very high rates. When configured as a Compton telescope in combination with a modern organic scintillator, such as p-terphenyl, sub-nanosecond coincidence resolving time allows dramatic suppression of background via time-of-flight (ToF) measurements, allowing both faint and bright gamma-ray line flares to be measured. The use of modern light readout devices, such as silicon photomultipliers (SiPMs), eliminates passive mass and permits a more compact, efficient instrument. We have flown a prototype Compton telescope using modern fast scintillators with SiPM readouts on a balloon test flight, achieving good ToF and spectroscopy performance. A larger balloon-borne instrument is currently in development. We present our test results and estimates of the solar flare sensitivity of a possible full-scale instrument suitable for flight on long-duration balloon flights or on an Explorer satellite platform.

Ryan, James Michael; Bloser, Peter; McConnell, Mark; Legere, Jason; Bancroft, Christopher; Murphy, Ronald; de Nolfo, Georgia

2015-04-01

259

Results of protective coating studies for the Hubble Space Telescope solar array  

NASA Technical Reports Server (NTRS)

An account is given of the methods, results, and interpretive conclusions obtained by a series of comprehensive performance verification/qualification tests conducted on candidate coatings for the Hubble Space Telescope's (HST) solar array. These coatings are intended to minimize the effects of orbital atomic oxygen impingement on exposed materials. Attention was given to atomic oxygen exposure, UV exposure, thermal cycling, and electron and proton exposure. The V-10 and CVI-1140-1 candidate coatings were demonstrated to be adequately resistant to a five-year HST mission's environmental exposure.

Linton, Roger C.; Gause, Raymond L.; Harwell, Roger J.; Dehaye, Robert F.; Burns, Howard Dewitt, Jr.; Reynolds, J. M.

1989-01-01

260

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

261

MAST: a mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei  

Microsoft Academic Search

The mass spectrometer telescope (MAST) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide high-resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z=2 to 28) over the energy range from ~10 to several hundred MeV\\/nucleon. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly

W. R. Cook; A. C. Cummings; J. R. Cummings; T. L. Garrard; B. Kecman; R. A. Mewaldt; R. S. Selesnick; E. C. Stone; T. T. von Rosenvinge

1993-01-01

262

The multi-conjugate adaptive optics system of the New Solar Telescope at Big Bear Solar Observatory  

NASA Astrophysics Data System (ADS)

We report on the multi-conjugate adaptive optics (MCAO) system of the New Solar Telescope (NST) at Big Bear Solar Observatory which has been integrated in October 2013 and is now available for MCAO experiments. The NST MCAO system features three deformable mirrors (DM), and it is purposely flexible in order to offer a valuable facility for development of solar MCAO. Two of the deformable mirrors are dedicated to compensation of field dependent aberrations due to high-altitude turbulence, whereas the other deformable mirror compensates field independent aberrations in a pupil image. The opto-mechanical design allows for changing the conjugate plane of the two high-altitude DMs independently between two and nine kilometers. The pupil plane DM can be placed either in a pupil image upstream of the high-altitude DMs or downstream. This capability allows for performing experimental studies on the impact of the geometrical order of the deformable mirrors and the conjugate position. The control system is flexible, too, which allows for real-world analysis of various control approaches. This paper gives an overview of the NST MCAO system and reveals the first MCAO corrected image taken at Big Bear Solar Observatory.

Schmidt, Dirk; Gorceix, Nicolas; Zhang, Xianyu; Marino, Jose; Coulter, Roy; Shumko, Sergey; Goode, Phil; Rimmele, Thomas; Berkefeld, Thomas

2014-07-01

263

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

264

Solar-B X-ray Telescope (XRT) Concept Study Report  

NASA Technical Reports Server (NTRS)

The X-ray observations from the Yohkoh SXT provided the greatest step forward in our understanding of the solar corona in nearly two decades. Expanding on the accomplishments of Yohkoh, we believe that the scientific objectives of the Solar-B mission are achieved with a significantly improved X-ray telescope (XRT) similar to the SXT. The Solar-B XRT will have twice the spatial resolution and a broader temperature response, while building on the knowledge gained from the successful Yohkoh mission. We present the scientific justification for this view, discuss the instrumental requirements that flow from the scientific objectives, and describe the instrumentation to meet these requirements. We then provide a detailed discussion of the design activities carried out during Phase A, noting the conclusions that were reached in terms of their implications for the detailed design activities which are now commencing. Details of the instrument that have changed as a result of the Phase A studied are specifically noted, and areas of concern going into Phase B are highlighted. XRT is a grazing-incidence (GI) modified Wolter I X-ray telescope, of 35cm inner diameter and 2.7m focal length. The 2048x2048 back-illuminated CCD (now an ISAS responsibility) has 13.5 micron pixels, corresponding to 1.0 arcsec and giving full Sun field of view. This will be the highest resolution GI X-ray telescope ever flown for Solar coronal studies, and it has been designed specifically to observe both the high and low temperature coronal plasma. A small optical telescope provides visible light images for co-alignment with the Solar-B optical and EUV instruments. The XRT science team is working in close cooperation with our Japanese colleagues in the design and construction of this instrument. All of the expertise and resources of the High Energy and Solar/Stellar Divisions of the Center for Astrophysics are being made available to this program, and our team will carry its full share of responsibility for mission operations, data reduction and education and public outreach. All aspects of the XRT design were reviewed during Phase A. The study focussed particularly on those aspects that have the greatest affect on instrument performance and extended lifetime, on the image quality error budget, and on the camera (mechanical and electrical) interface and the instrument mounting interfaces. The present instrument design differs in some details from that originally proposed. Selection of the XRT for Phase A study was contingent upon the removal of the camera and its associated electronics, and the acceptance of a stringent cost cap. The removal of the electronics left the XRT without control electronics for the instrument mechanisms. A mechanism controller was therefore added. The removal of the camera resulted in major complications to the integration and test plan. After many discussions, it was decided that the system would be less expensive, and the risk of unacceptable performance lower, if we include a focus mechanism. The remainder of the XRT design baseline matches the proposed configuration. Data requirements for the XRT are driven by the science plans, which are based on the physical processes in the solar outer atmosphere. Discussions to date of the XRT observing plan, both alone and in conjunction with the other Solar-B instruments, shows that the XRT needs 2 Gbits of on-board storage, at least one circulating buffer of 640 Mbits, and twelve 10- minute downlinks per day in order to carry out its required programs.

Golub, Leon

1999-01-01

265

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

266

TRANSVERSE OSCILLATIONS OF LOOPS WITH CORONAL RAIN OBSERVED BY HINODE/SOLAR OPTICAL TELESCOPE  

SciTech Connect

The condensations composing coronal rain, falling down along loop-like structures observed in cool chromospheric lines such as H{alpha} and Ca II H, have long been a spectacular phenomenon of the solar corona. However, considered a peculiar sporadic phenomenon, it has not received much attention. This picture is rapidly changing due to recent high-resolution observations with instruments such as the Hinode/Solar Optical Telescope (SOT), CRISP of the Swedish 1-m Solar Telescope, and the Solar Dynamics Observatory. Furthermore, numerical simulations have shown that coronal rain is the loss of thermal equilibrium of loops linked to footpoint heating. This result has highlighted the importance that coronal rain can play in the field of coronal heating. In this work, we further stress the importance of coronal rain by showing the role it can play in the understanding of the coronal magnetic field topology. We analyze Hinode/SOT observations in the Ca II H line of a loop in which coronal rain puts in evidence in-phase transverse oscillations of multiple strand-like structures. The periods, amplitudes, transverse velocities, and phase velocities are calculated, allowing an estimation of the energy flux of the wave and the coronal magnetic field inside the loop through means of coronal seismology. We discuss the possible interpretations of the wave as either standing or propagating torsional Alfven or fast kink waves. An estimate of the plasma beta parameter of the condensations indicates a condition that may allow the often observed separation and elongation processes of the condensations. We also show that the wave pressure from the transverse wave can be responsible for the observed low downward acceleration of coronal rain.

Antolin, P. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Verwichte, E., E-mail: patrick.antolin@astro.uio.no, E-mail: erwin.verwichte@warwick.ac.uk [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

2011-08-01

267

Transverse Oscillations of Loops with Coronal Rain Observed by Hinode/Solar Optical Telescope  

NASA Astrophysics Data System (ADS)

The condensations composing coronal rain, falling down along loop-like structures observed in cool chromospheric lines such as H? and Ca II H, have long been a spectacular phenomenon of the solar corona. However, considered a peculiar sporadic phenomenon, it has not received much attention. This picture is rapidly changing due to recent high-resolution observations with instruments such as the Hinode/Solar Optical Telescope (SOT), CRISP of the Swedish 1-m Solar Telescope, and the Solar Dynamics Observatory. Furthermore, numerical simulations have shown that coronal rain is the loss of thermal equilibrium of loops linked to footpoint heating. This result has highlighted the importance that coronal rain can play in the field of coronal heating. In this work, we further stress the importance of coronal rain by showing the role it can play in the understanding of the coronal magnetic field topology. We analyze Hinode/SOT observations in the Ca II H line of a loop in which coronal rain puts in evidence in-phase transverse oscillations of multiple strand-like structures. The periods, amplitudes, transverse velocities, and phase velocities are calculated, allowing an estimation of the energy flux of the wave and the coronal magnetic field inside the loop through means of coronal seismology. We discuss the possible interpretations of the wave as either standing or propagating torsional Alfvén or fast kink waves. An estimate of the plasma beta parameter of the condensations indicates a condition that may allow the often observed separation and elongation processes of the condensations. We also show that the wave pressure from the transverse wave can be responsible for the observed low downward acceleration of coronal rain.

Antolin, P.; Verwichte, E.

2011-08-01

268

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

269

Photometry's bright future: Detecting Solar System analogues with future space telescopes  

E-print Network

Time-series transit photometry from the Kepler space telescope has allowed for the discovery of thousands of exoplanets. We explore the potential of yet improved future missions such as PLATO 2.0 in detecting solar system analogues. We use real-world solar data and end-to-end simulations to explore the stellar and instrumental noise properties. By injecting and retrieving planets, rings and moons of our own solar system, we show that the discovery of Venus- and Earth-analogues transiting G-dwarfs like our Sun is feasible at high S/N after collecting 6yrs of data, but Mars and Mercury will be difficult to detect due to stellar noise. In the best cases, Saturn's rings and Jupiter's moons will be detectable even in single transit observations. Through the high number (>1bn) of observed stars by PLATO 2.0, it will become possible to detect thousands of single-transit events by cold gas giants, analogue to our Jupiter, Saturn, Uranus and Neptune. Our own solar system aside, we also show, through signal injection a...

Hippke, Michael

2015-01-01

270

Similitude modeling of natural convection heat transfer through an aperture in passive solar heated buildings  

NASA Astrophysics Data System (ADS)

An experimental study of natural convection heat transfer through a doorway in a two room passive solar heated building is described. Similitude modeling was the method used to measure natural convection heat transfer coefficients (h/sub NC/) in a model geometrically scaled down by a factor of 5. Freon gas was used as the working fluid to obtain dynamic similarity within the model. A temperature difference was maintained between the two rooms by a heated vertical wall which simulated a Trombe wall in one room, and by a cooled vertical wall which simulated a thermal storage wall in the other room. Heat transfer through the doorway was measured as a function of a characteristic temperature differential and the geometry of the doorway.

Weber, D. D.

1980-06-01

271

An Overview of the Electron-Proton and High Energy Telescopes for Solar Orbiter  

NASA Astrophysics Data System (ADS)

The Energetic Particle Detector (EPD) suite for ESA's Solar Orbiter will provide key measurements to address particle acceleration at and near the Sun. The EPD suite consists of four sensors (STEP, SIS, EPT, and HET). The University of Kiel in Germany is responsible for the design, development, and building of STEP, EPT and HET. This poster will focus on the last two. The Electron Proton Telescope (EPT) is designed to cleanly separate and measure electrons in the energy range from 20 - 400 keV and protons from 20 - 7000 keV. To separate electrons and protons EPT relies on the magnet/foil-technique. EPT is intended to close the gap between the supra-thermal particles measured by STEP and the high energy range covered by HET. The High-Energy Telescope (HET) will measure electrons from 300 keV up to about 30 MeV, protons from 10 to 100 MeV, and heavy ions from ~20 to 200 MeV/nuc. To achieve this performance HET consists of a series of silicon detectors in a telescope configuration with a scintillator calorimeter to stop high energy protons and ions. It uses the dE/dx vs. total E technique . In this way HET covers an energy range which is of interest for studies of the space radiation environment and will perform measurements needed to understand the origin of high-energy particle events at the Sun. EPT and HET share a common Electronics Box, there are two EPT-HET sensors on Solar Orbiter to allow rudimentary pitch-angle coverage. Here we present the current development status of EPT-HET units and calibration results of demonstration models as well as plans for future activities.

Boden, Sebastian; Kulkarni, Shrinivasrao R.; Tammen, Jan; Steinhagen, Jan; Martin, César; Wimmer-Schweingruber, Robert F.; Böttcher, Stephan I.; Seimetz, Lars; Ravanbakhsh, Ali; Elftmann, Robert; Rodriguez-Pacheco, Javier; Prieto Mateo, Manuel; Gomez Herrero, Rául

2014-05-01

272

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

273

Adaptive optics and aperture masking: a comparison  

Microsoft Academic Search

We present a comparative study of aperture-masking on the Keck-I telescope and adaptive optics with the Keck-II telescope. Recent results from an aperture-masking program at the Keck Observatory in the near-infrared amply demonstrate that this method occupies an important niche in achieving diffraction-limited images despite the many advances in adaptive optics technology. Examples of the efficacy of aperture-masking are the

Jayadev K. Rajagopal; Richard Barry; Bruno Lopez; William C. Danchi; John D. Monnier; Peter G. Tuthill; Charles H. Townes

2004-01-01

274

MAST - A mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei  

NASA Technical Reports Server (NTRS)

The Mass Spectrometer Telescope (MAST) on SAMPEX is designed to provide high resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z = 2 to 28) over the energy range from about 10 to several hundred MeV/nuc. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona, while during solar quiet times MAST will study the isotopic composition of galactic cosmic rays. In addition, MAST will measure the isotopic composition of both interplanetary and trapped fluxes of anomalous cosmic rays, believed to be a sample of the nearby interstellar medium.

Cook, Walter R.; Cummings, Alan C.; Cummings, Jay R.; Garrard, Thomas L.; Kecman, Branislav; Mewaldt, Richard A.; Selesnick, Richard S.; Stone, Edward C.; Von Rosenvinge, T. T.

1993-01-01

275

MAST - A mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei  

NASA Astrophysics Data System (ADS)

The Mass Spectrometer Telescope (MAST) on SAMPEX is designed to provide high resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z = 2 to 28) over the energy range from about 10 to several hundred MeV/nuc. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona, while during solar quiet times MAST will study the isotopic composition of galactic cosmic rays. In addition, MAST will measure the isotopic composition of both interplanetary and trapped fluxes of anomalous cosmic rays, believed to be a sample of the nearby interstellar medium.

Cook, Walter R.; Cummings, Alan C.; Cummings, Jay R.; Garrard, Thomas L.; Kecman, Branislav; Mewaldt, Richard A.; Selesnick, Richard S.; Stone, Edward C.; von Rosenvinge, T. T.

1993-05-01

276

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

277

Solar Orbiter spacecraft instrument interface simulator and its applications for the STIX telescope tests  

NASA Astrophysics Data System (ADS)

Solar Orbiter mission of European Space Agency, scheduled for launch in 2017, is designed to explore the Sun and the inner heliosphere. Its close, never achieved before by any other spacecraft, approach to the Sun as well as ten remote-sensing and in-situ on board instruments will allow obtaining unique solar science data. The Spectrometer Telescope for Imaging X-rays (STIX) is one of them. Its measurements of solar thermal and non-thermal hard X-ray emissions from ~4 to 150 keV will play an important role to achieve mission's major science goals. The Spacecraft Instrument Interface Simulator (SIIS) is specified as a part of Electrical Ground Support Equipment with the aim to provide a tool for power interface and telemetry/telecommand electrical and data protocol validation during the delivery phase of STIX instrument for spacecraft integration. It is designed to be used during the instrument development and test phases of onboard algorithms, too. Brief overview of SIIS use and performance for these purposes is given in this work.

?cis?owski, D.; Kowali?ski, M.; Podgórski, P.; Sylwester, J.; Orlea?ski, P.; Mrozek, T.; Ste?licki, M.; Barylak, J.; Barylak, A.; Skup, K. R.; Cichocki, A.; Ber, K.; Juchnikowski, G.

2014-11-01

278

Opto-thermal analysis of a lightweighted mirror for solar telescope  

E-print Network

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 gro...

Banyal, Ravinder K; Chatterjee, S

2013-01-01

279

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

280

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; Ariño, Javier; Murga, Gaizka; Goodrich, Bret; Hubbard, John R.; Greer, Alan; Mayer, Chris; Taylor, Philip

2012-09-01

281

New catadioptric telescope  

Microsoft Academic Search

The Acme telescope is a compound telescope that resembles the familiar Cassegrain type except that the main mirror is spherical and the secondary is an achromatic doublet mangin mirror. Three 6-in. aperture f\\/15 telescope designs are described. With a cemented, all spherical surface achromangin mirror, there is a small amount of coma which can be eliminated by redesigning with an

J. L. Richter

1981-01-01

282

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

283

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

284

LIST OF PARTICIPANTS AND DESCRIPTION OF WORK Network Title: EUROPEAN SOLAR MAGNETISM NETWORK  

E-print Network

the project period. · VTT (German Vacuum Tower Telescope), Tenerife, aperture 70 cm. General- purpose solarANNEX I LIST OF PARTICIPANTS AND DESCRIPTION OF WORK Network Title: EUROPEAN SOLAR MAGNETISM Objectives The Network science goal is to gain basic insight in the roots of solar magnetism by estab

Rutten, Rob

285

New Astronomy Reviews 42 (1998) 489492 Site tests for CLEAR by solar scintillometry  

E-print Network

. Beckers , Robert J. Rutten a 1 National Solar Observatory/NOAO, P.O. Box 26732, Tucson, AZ 85726, USA bNew Astronomy Reviews 42 (1998) 489­492 Site tests for CLEAR by solar scintillometry a b Jacques M the ongoing site survey for the NSO CLEAR project which aims to put a large-aperture solar telescope

Rutten, Rob

286

Photospheric and Chromospheric Dynamics of Sunspots Observed with New Solar Telescope  

NASA Astrophysics Data System (ADS)

The 1.6m New Solar Telescope (NST) of Big Bear Solar Observatory allows us to investigate the structure and dynamics of sunspots with unprecedented spatial and temporal resolutions. We present results of simultaneous observations of a sunspot in the photosphere with a broad-band TiO-line filter and in the chromospheric H-alpha line with Visible Imaging Spectrometer, and compare the observational results with MHD models of sunspots. The observations reveal previously unresolved features of the sunspot umbra and penumbra. In particular, the TiO data clearly demonstrate highly twisted dynamics of penumbral filaments and umbral dots and reveal strong shearing plasma flows in sunspot bridges, not explained by the MHD simulations. The high-resolution H-alpha spectroscopic data provide new views of the sunspot chromospheric dynamics, including the fine structure of oscillations and waves, penumbral jets, ubiquitous small-scale eruptions, and accretion flows in a form of dense plasma sheets. The diffraction-limited NST observations show that the sunspot dynamics is more complicated and much richer than it is described by the current sunspot models.

Kosovichev, Alexander G.; Yurchyshyn, Vasyl B.

2014-06-01

287

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

288

PET - A proton/electron telescope for studies of magnetospheric, solar, and galactic particles  

NASA Technical Reports Server (NTRS)

The Proton/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from about 1 to about 30 MeV and H and He nuclei from about 20 to about 300 MeV/nuc, with isotope resolution of H and He extending from about 20 to about 80 MeV/nuc. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O3 depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z greater than 2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources.

Cook, Walter R.; Cummings, Alan C.; Cummings, Jay R.; Garrard, Thomas L.; Kecman, Branislav; Mewaldt, Richard A.; Selesnick, Richard S.; Stone, Edward C.; Baker, Daniel N.; Von Rosenvinge, Tycho T.

1993-01-01

289

PET: a proton/electron telescope for studies of magnetospheric, solar, and galactic particles  

SciTech Connect

The Proton/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from [approximately]1 to [approximately]30 MeV and H and He nuclei from [approximately]20 to [approximately]300 MeV/nuc, with isotope resolution of H and He extending from [approximately]20 to [approximately]80 MeV/nuc. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O[sub 3] depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z > 2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources.

Cook, W.R.; Cummings, A.C.; Cummings, J.R.; Garrard, T.L.; Kecman, B.; Mewaldt, R.A.; Selesnick, R.S.; Stone, E.C. (California Inst. of Tech., Pasadena, CA (United States)); Baker, D.N.; Rosenvinge, T.T. von (Goddard Space Flight Center, Greenbelt, MD (United States)); Callis, L.B. (Langley Research Center, Hampton, VA (United States)); Blake, J.B.

1993-05-01

290

PET - A proton/electron telescope for studies of magnetospheric, solar, and galactic particles  

NASA Astrophysics Data System (ADS)

The Proton/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from about 1 to about 30 MeV and H and He nuclei from about 20 to about 300 MeV/nuc, with isotope resolution of H and He extending from about 20 to about 80 MeV/nuc. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O3 depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z greater than 2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources.

Cook, Walter R.; Cummings, Alan C.; Cummings, Jay R.; Garrard, Thomas L.; Kecman, Branislav; Mewaldt, Richard A.; Selesnick, Richard S.; Stone, Edward C.; Baker, Daniel N.; von Rosenvinge, Tycho T.

1993-05-01

291

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

292

Photon sieve telescope  

NASA Astrophysics Data System (ADS)

In designing next-generation, ultra-large (>20m) apertures for space, many current concepts involve compactable, curved membrane reflectors. Here we present the idea of using a flat diffractive element that requires no out-of-plane deformation and so is much simpler to deploy. The primary is a photon sieve - a diffractive element consisting of a large number of precisely positioned holes distributed according to an underlying Fresnel Zone Plate (FZP) geometry. The advantage of the photon sieve over the FZP is that all the regions are connected, so the membrane substrate under simple tension can avoid buckling. Also, the hole distribution can be varied to generate any conic or apodization for specialized telescope requirements such as exo-solar planet detection. We have designed and tested numerous photon sieves as telescope primaries. Some of these have over 10 million holes in a 0.1 m diameter aperture and all of them give diffraction limited imaging. While photon sieves are diffractive elements and thus suffer from dispersion, we will present two successful solutions to this problem.

Andersen, Geoff; Tullson, Drew

2006-06-01

293

Radio Telescopes  

NASA Astrophysics Data System (ADS)

``Radio Telescopes" starts with a brief historical introduction from Jansky's1931 discovery of radio emission from the Milky Way through the development ofradio telescope dishes and arrays to aperture synthesis imaging. It includessufficient basics of electromagnetic radiation to provide some understanding of thedesign and operation of radio telescopes. The criteria such as frequencyrange, sensitivity, survey speed, angular resolution, and field of view thatdetermine the design of radio telescopes are introduced. Because it is soeasy to manipulate the electromagnetic waves at radio frequencies, radiotelescopes have evolved into many different forms, sometimes with "wire"structures tuned to specific wavelengths, which look very different from anykind of classical telescope. To assist astronomers more familiar with otherwavelength domains, the appendix A.1. includes a comparison of radioand optical terminology. Some of the different types of radio telescopesincluding the filled aperture dishes, electronically steered phased arrays, andaperture synthesis radio telescopes are discussed, and there is a sectioncomparing the differences between dishes and arrays. Some of the morerecent developments including hierarchical beam forming, phased arrayfeeds, mosaicing, rotation measure synthesis, digital receivers, and longbaseline interferometers are included. The problem of increasing radiofrequency interference is discussed, and some possible mitigation strategies areoutlined.

Ekers, Ron; Wilson, Thomas L.

294

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

295

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 Å and Si IV 1393.76 Å 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

296

Formation Process of a Light Bridge Revealed with the Hinode Solar Optical Telescope  

E-print Network

The Solar Optical Telescope (SOT) aboard HINODE successfully and continuously observed a formation process of a light bridge in a matured sunspot of the NOAA active region 10923 for several days with high spatial resolution. During its formation, many umbral dots were observed emerging from the leading edges of penumbral filaments, and intruding into the umbra rapidly. The precursor of the light bridge formation was also identified as the relatively slow inward motion of the umbral dots which emerged not near the penumbra, but inside the umbra. The spectro-polarimeter on SOT provided physical conditions in the photosphere around the umbral dots and the light bridges. We found the light bridges and the umbral dots had significantly weaker magnetic fields associated with upflows relative to the core of the umbra, which implies that there was hot gas with weak field strength penetrating from subphotosphere to near the visible surface inside those structures. There needs to be a mechanism to drive the inward moti...

Katsukawa, Y; Berger, T E; Ichimoto, K; Kubo, M; Lites, B W; Nagata, S; Shimizu, T; Shine, R A; Suematsu, Y; Tarbell, T D; Title, A M; Tsuneta, S

2007-01-01

297

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

298

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

299

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

300

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

301

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

302

Design of a space telescope for vibration control  

NASA Astrophysics Data System (ADS)

The end of the Cold War has made large-aperture telescope technologies from the U.S. Strategic Defense Initiative program available for non-defense missions. Now, a four-meter aperture space telescope, a seventy percent larger aperture than that of the Hubble space telescope, has been proposed for a dual military and astronomical mission. An important part of the preliminary design work was to determine how to meet the telescope's pointing and jitter criteria. The telescope will be required to maintain an rms pointing accuracy of 24 nrad, preferably over periods of several hours. Vibration was a critical issue in the study because of the stringent pointing requirement, the relatively light structures desirable for spacecraft, thermal transients, the presence of disturbances from many spacecraft mechanisms (solar array drives, momentum wheels, thrusters, antenna steering mechanisms, etc.), and the many external appendages. The four-meter telescope design uses an inertial optical reference system combined with an actively controlled `fast steering mirror' in the target beam path to actively counteract vibration.

Dresner, Thomas L.; Freier, Larry J.; Chien, Tze T.; Gilmore, Jerold P.

1994-10-01

303

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

304

Impacts on Hubble Space Telescope solar arrays: discrimination between natural and man-made particles.  

NASA Astrophysics Data System (ADS)

A Post-Flight Investigation was initiated by the European Space Agency to analyze impact fluxes on solar arrays of the Hubble Space Telescope (HST), exposed to space for 8.25 years at approximately 600 km altitude. The solar cells were deployed during servicing mission SM-1 (December 1993), and retrieved by shuttle orbiter Columbia in March 2002 (SM-3B). A sub-panel of 2 m2 was cut from the --V2 wing and cells were selected for in-depth analysis. Twelve cells (9.6x10-3 m2) were surveyed for flux of all craters of sizes greater than 5 microns Dco; six at the NHM, and six at ONERA. Cumulative flux plots reveal slightly greater abundance of very small craters than in a comparable survey of SM-1 cells. Analytical scanning electron microscopy was used to locate impact features and to analyse residues at the NHM. 103 features of 3 -- 4000 micron conchoidal detachment diameter (Dco) were located on a total of 17 solar cells. 78 features show identifiable residue: 36 are Space Debris impacts and 42 Micrometeoroid impacts. Of the remaining 25: 4 contain residue of ambiguous origin, 1 is a minor manufacturing flaw, 1 is obscured by contamination, and 19 are unresolved, lacking recognizable residue. Space debris impacts on the SM-3B cells are all less than 80 microns Dco, dominated by Al- rich residue, probably of solid rocket motor origin, some may be unburnt fuel. Three craters may be sodium metal droplet impacts. No residues from paint pigment, aluminium or ferrous alloys, or copper- and tin-bearing metal were found. All craters larger than 100 microns are of micrometeoroid origin, or unresolved. Most residues are magnesium-iron silicate or iron sulfide. A few craters show vesicular Mg, S, Fe and Ni residue. A single Fe Ni metal residue was found, as well as enigmatic Mg- and S-bearing residues, all considered of micrometeoroid origin. A few Fe-, O- and C-bearing residues were classified as of ambiguous origin. The quality and quantity of residue is clearly linked to the crater pit morphology, with oval pit features containing more identifiable residue, perhaps due to lower peak shock pressures experienced in these oblique-incidence impacts.

Kearsley, A. T.; Drolshagen, G.; McDonnell, J. A. M.; Mandeville, J.-C.; Moussi, A.

305

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

306

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

307

A search for small solar-system bodies near the earth using a ground-based telescope - Technique and observations  

NASA Technical Reports Server (NTRS)

A large, previously undetected flux of small bodies near earth is identified by employing the standard technique of detection of an individual object in two consecutive frames. The observational periods and viewing coordinates for the search for small bodies are presented. A null test is performed in order to further demonstrate that the signatures in the images are not due to instrumental artifacts. The observed fluxes, orbital motions, and radii of the small bodies detected are in agreement with those for the small cometlike objects previously reported. It is pointed out that the radii of the small bodies would be in the range of meters. Since an alternative interpretation of the small bodies is possible, it is suggested that the use of a telescope with larger aperture and/or array detectors with lesser noise levels is necessary to confirm the present observations.

Frank, L. A.; Sigwarth, J. B.; Yeates, C. M.

1990-01-01

308

a Re-Evaluation of the Neutron Emission from the Solar Flare of September 07, 2005, Detected by the Solar Neutron Telescope at Sierra Negra.  

NASA Astrophysics Data System (ADS)

The X17.0 solar flare of September 7, 2005 released high-energy neutrons, which were detected by the Solar Neutron Telescope (SNT) at Sierra Negra, Mexico. In three separate and independent studies of this solar neutron event, the energy spectra was calculated as a power law. In this paper, we present an alternative analysis, based on improved numerical simulations of the detector using GEANT4, and a different technique to process the SNT data. The results indicate that the spectral index which best fits the neutron flux is around 3, in agreement with previous works. Based on the numerically calculated neutron energy deposition on the SNT, we confirm that the neutrons detected had at least 1 GeV, this implies that the parent solar flare most probably produced 10 GeV protons; these could not be observed at Earth, as theit was an east limb event.

González, Xavier

309

A CCD Imaging Spectrograph in the Improved Solar Tower of Nanjing-University  

Microsoft Academic Search

Since 1992 the solar tower telescope of Nanjing University (118°51' E, 32°03' N) as well as its multichannel solar spectrograph, originally established in 1982, have been reconstructed and a two-channel imaging spectrograph has been operated successfully. The apertures of the coelostat and the secondary mirror are both 60 cm. The spherical objective mirror, having an aperture of 43 cm and

Y. R. Huang; C. Fang; M. D. Ding; X. F. Gao; Z. G. Zhu; S. Y. Ying; J. Hu; Y. Z. Xue

1995-01-01

310

A CCD imaging spectrograph in the improved solar tower of Nanjing University  

Microsoft Academic Search

Since 1992 the solar tower telescope of Nanjing University (118°51' E, 32°03' N) as well as its multichannel solar spectrograph, originally established in 1982, have been reconstructed and a two-channel imaging spectrograph has been operated successfully. The apertures of the coelostat and the secondary mirror are both 60 cm. The spherical objective mirror, having an aperture of 43 cm and

Y. R. Huang; C. Fang; M. D. Ding; X. F. Gao; Z. G. Zhu; S. Y. Ying; J. Hu; Y. Z. Xue

1995-01-01

311

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

312

Sparse-aperture adaptive optics  

Microsoft Academic Search

Aperture masking interferometry and Adaptive Optics (AO) are two of the competing technologies attempting to recover diffraction-limited performance from ground-based telescopes. However, there are good arguments that these techniques should be viewed as complementary, not competitive. Masking has been shown to deliver superior PSF calibration, rejection of atmospheric noise and robust recovery of phase information through the use of closure

Peter Tuthill; James Lloyd; Michael Ireland; Frantz Martinache; John Monnier; Henry Woodruff; Theo ten Brummelaar; Nils Turner; Charles Townes

2006-01-01

313

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

314

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

315

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

316

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

317

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

318

Temperature of Solar Prominences Obtained with the Fast Imaging Solar Spectrograph on the 1.6 m New Solar Telescope at the Big Bear Solar Observatory  

NASA Astrophysics Data System (ADS)

We observed solar prominences with the Fast Imaging Solar Spectrograph (FISS) at the Big Bear Solar Observatory on 30 June 2010 and 15 August 2011. To determine the temperature of the prominence material, we applied a nonlinear least-squares fitting of the radiative transfer model. From the Doppler broadening of the H? and Ca ii lines, we determined the temperature and nonthermal velocity separately. The ranges of temperature and nonthermal velocity were 4000 - 20 000 K and 4 - 11 km s-1. We also found that the temperature varied much from point to point within one prominence.

Park, Hyungmin; Chae, Jongchul; Song, Donguk; Maurya, Ram Ajor; Yang, Heesu; Park, Young-Deuk; Jang, Bi-Ho; Nah, Jakyoung; Cho, Kyung-Suk; Kim, Yeon-Han; Ahn, Kwangsu; Cao, Wenda; Goode, Philip R.

2013-11-01

319

QUIESCENT PROMINENCE DYNAMICS OBSERVED WITH THE HINODE SOLAR OPTICAL TELESCOPE. I. TURBULENT UPFLOW PLUMES  

SciTech Connect

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{sup -1}, which is supersonic for a {approx}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{sup -1}. Typical lifetimes range from 300 to 1000 s ({approx}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 km{sup 2} s{sup -1} reaching maximum projected areas from 2 to 15 Mm{sup 2}. 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 [Lockheed Martin Solar and Astrophysics Laboratory, B/252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Lites, Bruce W. [High Altitude Observatory, University Center for Atmospheric Research, Boulder, CO (United States); Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Shimizu, Toshifumi, E-mail: berger@lmsal.co [Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 (Japan)

2010-06-20

320

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

321

CCD camera systems and support electronics for a White Light Coronagraph and X-ray XUV solar telescope  

NASA Technical Reports Server (NTRS)

Two instruments, a White Light Coronagraph and an X-ray XUV telescope built into the same housing, share several electronic functions. Each instrument uses a CCD as an imaging detector, but due to different spectral requirements, each uses a different type. Hardware reduction, required by the stringent weight and volume allocations of the interplanetary mission, is made possible by the use of a microprocessor. Most instrument functions are software controlled with the end use circuits treated as peripherals to the microprocessor. The instruments are being developed for the International Solar Polar Mission.

Harrison, D. C.; Kubierschky, K.; Staples, M. H.; Carpenter, C. H.

1980-01-01

322

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

323

Off-limb EUV observations of the solar corona and transients with the CORONAS-F/SPIRIT telescope-coronagraph  

NASA Astrophysics Data System (ADS)

The SPIRIT telescope aboard the CORONAS-F satellite (in orbit from 26 July 2001 to 5 December 2005), observed the off-limb solar corona in the 175 Å (Fe IX, X and XI lines) and 304 Å (He II and Si XI lines) bands. In the coronagraphic mode the mirror was tilted to image the corona at the distance of 1.1...5 Rsun from the solar center, the outer occulter blocked the disk radiation and the detector sensitivity was enhanced. This intermediate region between the fields of view of ordinary extreme-ultraviolet (EUV) telescopes and most of the white-light (WL) coronagraphs is responsible for forming the streamer belt, acceleration of ejected matter and emergence of slow and fast solar wind. We present here the results of continuous coronagraphic EUV observations of the solar corona carried out during two weeks in June and December 2002. The images showed a "diffuse" (unresolved) component of the corona seen in both bands, and non-radial, ray-like structures seen only in the 175 Å band, which can be associated with a streamer base. The correlations between latitudinal distributions of the EUV brightness in the corona and at the limb were found to be high in 304 Å at all distances and in 175 Å only below 1.5 Rsun. The temporal correlation of the coronal brightness along the west radial line, with the brightness at the underlying limb region was significant in both bands, independent of the distance. On 2 February 2003 SPIRIT observed an expansion of a transient associated with a prominence eruption seen only in the 304 Å band. The SPIRIT data have been compared with the corresponding data of the SOHO LASCO, EIT and UVCS instruments.

Slemzin, V.; Bougaenko, O.; Ignatiev, A.; Kuzin, S.; Mitrofanov, A.; Pertsov, A.; Zhitnik, I.

2008-10-01

324

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

325

NEAT: an astrometric space telescope to search for habitable exoplanets in the solar neighborhood  

NASA Astrophysics Data System (ADS)

The last decade has witnessed a spectacular development of exoplanet detection techniques, which led to an exponential number of discoveries and a great diversity of known exoplanets. However, it must be noted that the quest for the holy grail of astrobiology, i.e. a nearby terrestrial exoplanet in habitable zone around a solar type star, is still ongoing and proves to be very hard. Radial velocities will have to overcome stellar noise if there are to discover habitable planets around stars more massive than M ones. For very close systems, transits are impeded by their low geometrical probability. Here we present an alternative concept: space astrometry. NEAT (Nearby Earth Astrometric Telescope) is a concept of astrometric mission proposed to ESA which goal is to make a whole sky survey of close (less then 20 pc) planetary systems. The detection limit required for the instrument is the astrometric signal of an Earth analog (at 10 pc). Differential astrometry is a very interesting tool to detect nearby habitable exoplanets. Indeed, for F, G and K main sequence stars, the astrophysical noise is smaller than the astrometric signal, contrary to the case for radial velocities. The difficulty lies in the fact that the signal of an exo-Earth around a G type star at 10 pc is a tiny 0.3 micro arc sec, which is equivalent to a coin on the moon, seen from the Earth: the main challenge is related to instrumentation. In order to reach this specification, NEAT consists of two formation flying spacecraft at a 40m distance, one carries the mirror and the other one the focal plane. Thus NEAT has a configuration with only one optical surface: an off-axis parabola. Consequently, beamwalk errors are common to the whole field of view and have a small effect on differential astrometry. Moreover a metrology system projects young fringes on the focal plane, which can characterize the pixels whenever necessary during the mission. NEAT has two main scientific objectives: combined with radial velocities and direct imaging, it will explore in a quasi systematic way the nearby planetary systems. The resulting catalog of planetary systems will be very useful to constrain planetary formation models. The second objective is to find very close Earth analogs. These will be top priority targets for a spectroscopic mission aimed at detecting biomarquers. The current activities related to NEAT revolve around 3 themes: i) a lab demonstration: an optical bench replicates the NEAT optical configuration and metrology system in order to demonstrate the feasibility of measuring centroids with a differential accuracy of 5 µpixels (corresponding to 0.3 micro arc sec on sky) ii) a definition phase study of the NEAT mission done by CNES (the "French Space Agency") iii) an end to end simulation of the NEAT data reduction pipeline: from astrometric and RVs measurements to planets All of these activities are focused on the need to answer the next ESA call for M class missions in 2014 with an improved NEAT concept.

Crouzier, A.; Malbet, F.; Kern, P.; Feautrier, P.; Preiss, O.; Martin, G.; Henault, F.; Stadler, E.; Lafrasse, S.; Behar, E.; Saintpe, M.; Dupont, J.; Potin, S.; Lagage, P.-O.; Cara, C.; Leger, A.; Leduigou, J.-M.; Shao, M.; Goullioud, R.

2014-03-01

326

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

NASA Technical Reports Server (NTRS)

The following major activities were advanced or completed: complete design of the entire telescope assembly and fabrication of all front-end components; specification of all rocket skin sections including bulkheads, feedthroughs and access door; fabrication, curing, and delivery of the large graphite-epoxy telescope tube; engineering analysis of the primary mirror vibration test was completed and a decision made to redesign the mirror attachment to a kinematic three-point mount; detail design of the camera control, payload and housekeeping electronics; and multilayer mirror flats with 2d spacings of 50 A and 60 A.

Golub, L.

1985-01-01

327

Solar filter for the Mars laser communication demonstration optical receiver  

Microsoft Academic Search

To maximize the cost-effectiveness of the Mars Laser Communication Demonstration (MLCD), the project is pursuing the use of ground-based astronomical telescopes as large-aperture optical receiving antennae. To facilitate communication as the spacecraft approaches solar conjunction, a large membrane filter is being considered to reject approximately 95% of the sun\\

Brian G. Patrick; Paul Gierow; David Sheikh; W. Tom Roberts

2004-01-01

328

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

329

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

330

Ion implantation for figure correction of high-resolution x-ray telescope mirrors  

E-print Network

Fabricating mirrors for future high-resolution, large-aperture x-ray telescopes continues to challenge the x-ray astronomy instrumentation community. Building a large-aperture telescope requires thin, lightweight mirrors; ...

Chalifoux, Brandon D

2014-01-01

331

AAVSO Solar Observers Worldwide  

NASA Astrophysics Data System (ADS)

(Abstract only) For visual solar observers there has been no biological change in the "detector" (human eye) - at century scales (eye + visual cortex) does not change much over time. Our capacity to "integrate" seeing distortions is not just simple averaging! The visual cortex plays an essential role, and until recently only the SDO-HMI (Solar Dynamics Observatory, Helioseismic and Magnetic Imager) has had the capacity to detect the smallest sunspots, called pores. Prior to this the eye was superior to photography and CCD. Imaged data are not directly comparable or substitutable to counts by eye, as the effects of sensor/optical resolution and seeing will have a different influence on the resulting sunspot counts for images when compared to the human eye. Also contributing to the complex task of counting sunspots is differentiating between a sunspot (which is usually defined as having a darker center (umbra) and lighter outer ring (penumbra)) and a pore, made even more complex by the conflicting definitions of the word "pore" in the solar context: "pore" can mean a small spot without penumbra or "pore" can mean a random intergranular blemish that is not a true sunspot. The overall agreement is that the smallest spot size is near 2,000 km or ~3 arc sec, (Loughhead, R. E. and Bray, R. J. 1961, Australian J. Phys., 14, 347). Sunspot size is dictated by granulation dynamics rather than spot size (cancellation of convective motion), and by the lifetime of the pore, which averages from 10 to 30 minutes. There is no specific aperture required for AAVSO observers contributing sunspot observations. However, the detection of the smallest spots is influenced by the resolution of the telescope. Two factors to consider are the theoretical optical resolution (unobstructed aperture), Rayleigh criterion: theta = 138 / D(mm), and Dawes criterion: theta = 116 / D(mm) (http://www.telescope-optics.net/telescope_resolution.htm). However, seeing is variable with time; daytime range will be similar for all low-altitude sites, within the range of 1.5 to 3 arc sec, (typically = 2 arc sec equivalent diameter D = 45-90 mm, the typical solar scope = 70 mm aperture). Where large apertures are more affected by size of turbulent eddies ~8-12 cm, small-aperture telescopes reduce these differences, i.e. large aperture is not always beneficial.

Howe, R.

2013-06-01

332

Mg IX emission lines in an active region spectrum obtained with the Solar EUV Rocket Telescope and Spectrograph (SERTS)  

NASA Technical Reports Server (NTRS)

Theoretical electron-temperature-sensitive Mg IX emission line ratios are presented for R(sub 1) = I(443.96 A)/I(368.06 A), R(sub 2) = I(439.17 A)/I(368.06 A), R(sub 3) = I(443.37 A)/I(368.06 A), R(sub 4) = I(441.22 A)/I(368.06 A), and R(sub 5) = I(448.28 A)/I(368.06 A). A comparison of these with observational data for a solar active region, obtained during a rocket flight by the Solar EUV Rocket Telescope and Spectrograph (SERTS), reveals excellent agreement between theory and observation for R(sub 1) through R(sub 4), with discrepancies that average only 9%. This provides experimental support for the accuracy of the atomic data adopted in the line ratio calculations, and also resolves discrepancies found previously when the theoretical results were compared with solar data from the S082A instrument on board Skylab. However in the case of R(sub 5), the theoretical and observed ratios differ by almost a factor of 2. This may be due to the measured intensity of the 448.28 A line being seriously affected by instrumental effects, as it lies very close to the long wavelength edge of the SERTS spectral coverage (235.46-448.76 A).

Keenan, F. P.; Thomas, R. J.; Neupert, W. M.; Conlon, E. S.

1994-01-01

333

Large bearings with incorporated gears, high stiffness, and precision for the Swedish Solar Telescope (SST) on La Palma  

NASA Astrophysics Data System (ADS)

The 1-meter Swedish Solar Telescope (SST) obtains images of the solar surface with an unprecedented resolution of 0.1 arcsec. It consists of a relatively slender tower with on top only the vacuum turret for reflecting downward the solar beam and no protective dome. This is a favourable situation to get good local seeing. Just in the case of some wind, seeing is best for daytime observations, therefore the precision bearings and drives of the elevation- and azimuth axis of the turret have to be stiff against wind. This requires line contact between the meshing teeth of the large gear wheel and the pinion. High preload forces to achieve line contact are not allowed because of appearing stick-slip effects. To reduce the risk on stick-slip a special design of the teeth for high stiffness combined with low friction and smooth transition from one tooth to the next was made. Furthermore, extreme precision in the fabrication was pursued such that relatively small contact forces give already line contact. This required a special order of the successive fabrication steps of the combination of bearing and gear teeth. An additional problem was the relatively thin section of the bearings required for a compact turret construction, needed for best local seeing and minimum wind load. Solutions for all these problems will be discussed. For the large gears the exceptional good DIN quality class 4 for the pitch precision and straightness plus direction of the teeth faces was achieved.

Hammerschlag, Robert H.; Bettonvil, Felix C. M.; Jägers, Aswin P. L.; Scharmer, Göran B.

2006-06-01

334

Hubble Space Telescope Deployment-Artist's Concept  

NASA Technical Reports Server (NTRS)

This artist's concept depicts the Hubble Space Telescope after being released into orbit, with the high gain anternas and solar arrays deployed and the aperture doors opened. The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is 42.5-feet (13-meters) long and weighs about 25,000 pounds (11,600 kilograms). The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

1980-01-01

335

New catadioptric telescope  

NASA Astrophysics Data System (ADS)

The Acme telescope is a compound telescope that resembles the familiar Cassegrain type except that the main mirror is spherical and the secondary is an achromatic doublet mangin mirror. Three 6-in. aperture f/15 telescope designs are described. With a cemented, all spherical surface achromangin mirror, there is a small amount of coma which can be eliminated by redesigning with an air space between the crown and flint elements of the achromangin mirror, or by cementing them with one of the concave external surfaces of achromangin figured to an hyperboloid. In the examples, the spherical aberration is nil and the chromatic residual is roughly half that of an achromatic objective of the same speed, aperture, and glass types. Readily available crown and flint glasses such as Schott BK-7 and F-2 are entirely satisfactory for the achromangin mirror. Also considered are two examples of Acme-like telescopes with paraboloidal instead of spherical main mirrors.

Richter, J. L.

1981-01-01

336

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

337

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

338

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

339

ATM photoheliograph. [at a solar observatory  

NASA Technical Reports Server (NTRS)

The design and fabrication are presented of a 65 cm photoheliograph functional verification unit (FVU) installed in a major solar observatory. The telescope is used in a daily program of solar observation while serving as a test bed for the development of instrumentation to be included in early space shuttle launched solar telescopes. The 65 cm FVU was designed to be mechanically compatible with the ATM spar/canister and would be adaptable to a second ATM flight utilizing the existing spar/canister configuration. An image motion compensation breadboard and a space-hardened, remotely tuned H alpha filter, as well as solar telescopes of different optical configurations or increased aperture are discussed.

Prout, R. A.

1975-01-01

340

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

341

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

PubMed

We appreciate the thoughtful comments by Kellerer [Appl. Opt.53, 7643 (2014)10.1364/AO.53.007643] to our recent study [Appl. Opt.53, 685 (2014)10.1364/AO.53.000685] in which we evaluate the practicability of a layer-oriented wavefront sensing approach suggested for use in solar multiconjugate adaptive optics. After careful review of Kellerer's comment, we remain cautious about the feasibility of a solar-layer-oriented Shack-Hartmann wavefront sensor. However, we strongly encourage further analysis and proof-of-concept work that addresses the difficulties outlined in our original paper and that demonstrates the operating principles behind such an instrument. PMID:25402985

Marino, Jose; Wöger, Friedrich

2014-11-10

342

RATAN-600 radio telescope in the 24th solar-activity cycle. III. System of data acquisition and control of the solar spectral facility  

NASA Astrophysics Data System (ADS)

We report the development of a multichannel data acquisition and control system for the Spectral and Polarization High-Resolution Solar Research System, installed at the RATAN-600 radio telescope. This facility provides high-speed registration of signals from 240 channels and controls the preparation for observations and the process of automatic observations. The hardware is made in the form factor of 3U Evromekhanika modules. The measurement facility is controlled by the software based on the QT cross-platform library (the open source version), which can be run both on Linux and Windows operating systems. The data are written to a magnetic carrier and then transferred to the computer network of the Special Astrophysical Observatory for archiving, and can be accessed by external users.

Baldin, S. V.; Garaimov, V. I.

2011-07-01

343

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

344

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

E-print Network

of minor bodies of Solar System, such as Near Earth Objects (NEOs), Main belt asteroids, binary ). 2. Research of Near Earth Objects and binary and multiple asteroids 2.1 Discovering With MTM-500M.2 Research and observations of 2008 TC3 asteroid impacted to the Earth in 7 October 2008 On October 6, 2008

Boyer, Edmond

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

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

347

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 Å 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

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

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

350

Optical Set-Up and Design for Solar Multi-conjugate Adaptive Optics at the 1.6m New Solar Telescope, Big Bear Solar Observatory  

NASA Astrophysics Data System (ADS)

The Sun is an ideal target for the development and application of Multi-Conjugate Adaptive Optics (MCAO). A solar MCAO system is being developed by the Big Bear Solar Observatory, for the 1.6m New Solar Observatory, with the purpose of extending the corrected science field of view to 1.00Arcmin. A preliminary optical set-up, design and optical performance for such a system is presented and discussed here.

Moretto, Gil; Langlois, Maud; Goode, Philip; Gorceix, Nicolas; Shumko, Sergey

2013-12-01

351

Preliminary design analysis for the solar optical telescope main mirror actuator  

NASA Technical Reports Server (NTRS)

The resolution of the SOT Gregorian telescope was maintained if the conic foci of the elliptical secondary and parabolic primary were made to coincide within plus or minus 38 microns across the prime focus plane and to within 5 microns in focus. An error in coincidence across the focal plane caused all point images to show additional coma with all the comatic tails pointing in the same direction. An error in focus became magnified by the square of the magnification of the secondary and simply increased the diameter of the point source. Offsetting or rastering the sun may be accomplished by swinging the primary in an arc about the point of coincidence of the conic foci so long as the coincidence is kept to within the tolerance stated.

Dunn, R. B.

1977-01-01

352

Spectral researches of solar system giant planets using 2-m telescope at the Peak Terskol  

NASA Astrophysics Data System (ADS)

Results of observations, processing and an analysis of Uranus and Neptune spectra obtained from 2001-2012 are presented. Observations were carried out at the peak Terskol observatory (Northern Caucasus, Russia) using the coude échelle high-resolution spectrograph and the 2-meter mirror telescope Zeiss-2000. Data were obtained with spectral resolution R=45000 within 3700 - 9000 Ångstroms range. Combination of the specified equipment and spectral resolution allowed to solve the following problems: detecting of contribution of Raman scattering in planet spectra; calculating of spectral geometric albedo Ag taking into account of Raman scattering; research of long- and short-periodic variations for Ag and intensities of some chosen spectral lines; calculations of vertical structure parameters of giant planet atmospheres; search of ammonia NH3 lines in planet spectra. A comparative analysis of Uranus and Neptune spectra for different years was done.

Kuznyetsova, Yu.; Matsiaka, O.; Shliakhetskaya, Ya.; Krushevska, V.; Vidmachenko, A.; Andreev, M.; Sergeev, A.

2014-03-01

353

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

354

CHROMOSPHERIC SIGNATURES OF SMALL-SCALE FLUX EMERGENCE AS OBSERVED WITH NEW SOLAR TELESCOPE AND HINODE INSTRUMENTS  

SciTech Connect

With the ever-increasing influx of high-resolution images of the solar surface obtained at a multitude of wavelengths, various processes occurring at small spatial scales have become a greater focus of our attention. Complex small-scale magnetic fields have been reported that appear to have enough stored energy to heat the chromosphere. While significant progress has been made in understanding small-scale phenomena, many specifics remain elusive. We present here a detailed study of a single event of disappearance of a magnetic dipole and associated chromospheric activity. Based on New Solar Telescope H{alpha} data and Hinode photospheric line-of-sight magnetograms and Ca II H images, we report the following. (1) Our analysis indicates that even very small dipoles (elements separated by about 0.''5 or less) may reach the chromosphere and trigger non-negligible chromospheric activity. (2) Careful consideration of the magnetic environment where the new flux is deposited may shed light on the details of magnetic flux removal from the solar surface. We argue that the apparent collision and disappearance of two opposite polarity elements may not necessarily indicate their cancellation (i.e., reconnection, emergence of a 'U' tube, or submergence of {Omega} loops). In our case, the magnetic dipole disappeared by reconnecting with overlying large-scale inclined plage fields. (3) Bright points (BPs) seen in off-band H{alpha} images are very well correlated with the Ca II H BPs, which in turn are cospatial with G-band BPs. We further speculate that, in general, H{alpha} BPs are expected to be cospatial with photospheric BPs; however, a direct comparison is needed to refine their relationship.

Yurchyshyn, V. B.; Goode, P. R.; Abramenko, V. I.; Chae, J.; Cao, W.; Andic, A.; Ahn, K. [Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 (United States)

2010-10-20

355

Imaging of the solar atmosphere by the Siberian Solar Radio Telescope at 5.7 GHz with an enhanced dynamic range  

E-print Network

The Siberian Solar Radio Telescope (SSRT) is a solar-dedicated directly-imaging interferometer observing the Sun at 5.7 GHz. The SSRT operates in the two-dimensional mode since 1996. The imaging principle of the SSRT restricts its opportunities in observations of very bright flare sources, while it is possible to use `dirty' images in studies of low brightness features, which do not overlap with side lobes from bright sources. The interactive CLEAN technique routinely used for the SSRT data provides imaging of active regions but consumes much time and efforts and does not reveal low-brightness features below the CLEAN threshold. The newly developed technique combines the CLEAN routine with the directly imaging capability of the SSRT and provides clean images with an enhanced dynamic range automatically. These elaborations considerably extend the range of tasks, which can be solved with the SSRT. We show some examples of the present opportunities of the SSRT and compare its data with the images produced by the...

Kochanov, Alexey; Prosovetsky, Dmitry; Rudenko, George; Grechnev, Victor

2013-01-01

356

Telescopic vision contact lens  

NASA Astrophysics Data System (ADS)

We present the concept, optical design, and first proof of principle experimental results for a telescopic contact lens intended to become a visual aid for age-related macular degeneration (AMD), providing magnification to the user without surgery or external head-mounted optics. Our contact lens optical system can provide a combination of telescopic and non-magnified vision through two independent optical paths through the contact lens. The magnified optical path incorporates a telescopic arrangement of positive and negative annular concentric reflectors to achieve 2.8x - 3x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

Tremblay, Eric J.; Beer, R. Dirk; Arianpour, Ashkan; Ford, Joseph E.

2011-03-01

357

Interface Region Imaging Spectrograph (IRIS) entrance aperture design  

NASA Astrophysics Data System (ADS)

The Interface Region Imaging Spectrograph (IRIS) is a complementary follow-on to Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO-AIA) and funded as a member of the NASA SMEX program. This paper presents the thermal design of the IRIS telescope front end, with a focus on the IRIS door and entrance aperture assembly. The challenge of the IRIS entrance aperture, including the door design, was to manage the solar flux, both before and after the door was opened. This is especially a problem with instruments that are permanently pointed directly at the sun. Though there is an array of effective flux-rejecting coatings, they are expensive, hard to apply, harder to measure, delicate, prone to unpredictable performance decay with exposure, and very often a source of contamination. This paper presents a thermal control and protection method based on robust, inexpensive coatings and materials, combined to produce high thermal and structural isolation. The end result is a first line of thermal protection whose performance is easy to predict and well isolated from the instrument it is protecting.

Cheimets, P.; Park, S.; Bergner, H.; Chou, C.; Gates, R.; Honsa, M.; Podgorski, W.; Yanari, C.

2014-07-01

358

Phase diversity for segmented and multi-aperture systems  

Microsoft Academic Search

As telescopes become larger, segmented and multi-aperture designs are being implemented to meet cost, size and weight constraints. These systems require alignment of the segments or sub-apertures to within fractions of a wavelength. We investigate the performance of phase diversity, a technique of image-based wavefront sensing, for characterizing and aligning segmented and multi-aperture systems. Supporting work developing the core phase-diversity

Matthew R. Bolcar

2009-01-01

359

HILT - A heavy ion large area proportional counter telescope for solar and anomalous cosmic rays  

NASA Technical Reports Server (NTRS)

The HILT sensor has been designed to measure heavy ion elemental abundances, energy spectra, and direction of incidence in the mass range from He to Fe and in the energy range 4 to 250 MeV/nucleon. With its large geometric factor of 60 sq cm sr the sensor is optimized to provide compositional and spectral measurements for low intensity cosmic rays (i.e. for small solar energetic particle events and for the anomalous component of cosmic rays). The instrument combines a large area ion drift chamber-proportional counter system with two arrays of 16 Li-drift solid state detectors and 16 CsI crystals. The multi dE/dx-E technique provides a low background mass and energy determination. The sensor also measures particle direction. Combining these measurements with the information on the spacecraft position and attitude in the low-altitude polar orbit, it will be possible to infer the ionic charge of the ions from the local cutoff of the Earth's magnetic field. The ionic charge in this energy range is of particular interest because it provides unique clues to the origin of these particles and has not been investigated systematically so far. Together with the other instruments on board SAMPEX (LEICA, MAST, and PET), a comprehensive measurement of the entire solar and anomalous particle population will be achieved.

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

1993-01-01

360

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

361

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

NASA Technical Reports Server (NTRS)

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, A.; Cirtain, J.; Golub, L.; DeLuca, E.; Savage, S.; Alexander, C.; Schuler, T.

2014-01-01

362

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

NASA Technical Reports Server (NTRS)

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 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 percent 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, A.; Cirtain, J.; Golub, L.; DeLuca, E.; Savage, S.; Alexander, C.; Schuler, T.

2014-01-01

363

Thermal Properties of A Solar Coronal Cavity Observed with the X-Ray Telescope on Hinode  

NASA Technical Reports Server (NTRS)

Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers. In this study, we use data from the X-ray Telescope (XRT) on the Hinode satellite to examine the thermal emission properties of a cavity observed during July 2008 that contains bright X-ray emission in its center. Using ratios of XRT filters, we find evidence for elevated temperatures in the cavity center. The area of elevated temperature evolves from a ring-shaped structure at the beginning of the observation, to an elongated structure two days later, finally appearing as a compact round source four days after the initial observation. We use a morphological model to fit the cavity emission, and find that a uniform structure running through the cavity does not fit the observations well. Instead, the observations are reproduced by modeling several short cylindrical cavity "cores" with different parameters on different days. These changing core parameters may be due to some observed activity heating different parts of the cavity core at different times. We find that core temperatures of 1.75 MK, 1.7 MK and 2.0 MK (for July 19, July 21 and July 23, respectively) in the model lead to structures that are consistent with the data, and that line-of-sight effects serve to lower the effective temperature derived from the filter ratio.

Reeves, Katherine K.; Gibson, Sarah E.; Kucera, Theresa A.; Hudson, Hugh S.; Kano, Ryouhei

2011-01-01

364

The application of Fourier transform spectroscopy to the remote identification of solids in the solar system  

Microsoft Academic Search

The techniques of Fourier transform spectroscopy combined with large aperture telescopes and advances in detector technology now permit infrared (at a wavelength greater than 1 micron) observations of the surfaces of small solar system objects such as asteroids and satellites. The results demonstrate that this activity can produce important new compositional information related to the origin and evolution of the

H. P. Larson; Uwe Fink

1977-01-01

365

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

366

The large binocular telescope.  

PubMed

The Large Binocular Telescope (LBT) Observatory is a collaboration among institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio, and Virginia. The telescope on Mount Graham in Southeastern Arizona uses two 8.4 m diameter primary mirrors mounted side by side. A unique feature of the LBT is that the light from the two Gregorian telescope sides can be combined to produce phased-array imaging of an extended field. This cophased imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65 m aperture and a collecting area equivalent to an 11.8 m circular aperture. This paper describes the design, construction, and commissioning of this unique telescope. We report some sample astronomical results with the prime focus cameras. We comment on some of the technical challenges and solutions. The telescope uses two F/15 adaptive secondaries to correct atmospheric turbulence. The first of these adaptive mirrors has completed final system testing in Firenze, Italy, and is planned to be at the telescope by Spring 2010. PMID:20517352

Hill, John M

2010-06-01

367

Hosting the Student Telescope Network First Site  

NASA Astrophysics Data System (ADS)

The demonstration site for the Student Telescope Network, and for the first practical public-use Internet observatory, as powered by iBisque software, is at New Mexico Skies in southern New Mexico (www.nmskies.com). The observatory site, located approximately 14 miles northeast of the Apache Point Observatory and the Sunspot National Solar Observatory, is at 2,225 meters elevation in the southern Sacramento Mountains of New Mexico. It has very dark transparent skies, excellent weather conditions, good seeing and a high proportion of clear photometric nights. The Internet observatory pod concept includes placing multiple telescopes (as many as twelve), in each of several 32-foot roll-off roof observatories. The 14 to 16 inch aperture telescopes, mounted on accurately pointing and tracking Bisque "Paramounts" (www.bisque.com), plus KAF-1001E CCD cameras, are controlled with a browser-based sky-map GUI (patent pending) control system also developed by Software Bisque. We provide detail on the concept and its implementation. As of mid-March, 2002, the first demonstration telescope has been operating nightly for about 60 days. Over 420 users have registered on the telescope server, more than 2,000 images have been taken and their FITS files downloaded to users' computers all over the world. In this and the companion poster, we report our experiences over the period of the February-May (2002) trial period, including technical challenges and performance measures on the Internet observatory's operations. We further detail lessons learned for future development of browser-based Internet observatories for high school/college level instructional use, and lessons applicable to the use of Internet-based telescopes for serious astronomical research as well. We thank the Institute for Connecting Science Research to the Classroom for a grant to the University of Denver in support of this Internet telescope services pilot project.

Rice, M.; Bisque, S. T. M. D.; Stencel, R. E.

2002-05-01

368

Optical vortex coronagraphy with an elliptical aperture.  

PubMed

An optical vortex coronagraph that makes efficient use of a larger fraction of the clear aperture of a Cassegrain-type telescope is described. This design incorporates an elliptical subaperture rather than the conventional circular subaperture. We derive a new vortex phase mask that maintains the same theoretical contrast of a circularly symmetric vortex coronagraph. PMID:23314632

Ruane, Garreth J; Swartzlander, Grover A

2013-01-10

369

Rantiga Osservatorio, Tincana (MPC-D03): Observations and searching for small Solar System bodies using a remotely controlled telescope  

NASA Astrophysics Data System (ADS)

Rantiga Osservatorio is the first Polish project aimed at discovering and observing small solar-system objects, including near-Earth objects and comets. The observatory officially started in March 2012, as a result of cooperation between two amateur astronomers: Michal Zolnowski and Michal Kusiak. Subsequently, our station received official designation D03 assigned by the IAU's Minor Planet Center. The equipment is installed in northern Italy, on the border between Emilia-Romagna and Tuscany, in the small village of Tincana at an altitude of 643 m. The heart of the observatory is a 0.4-meter reflector f/3.8, mounted on Paramount ME and CCD camera SBIG STX-16803. The equipment is controlled by an industrial computer connected to the internet, and software allowing for automation and remote control of the telescope from Poland. It is also the first Polish amateur observatory which has been used for the discoveries of potentially new asteroids since 1949. Between 2012 and 2013, Rantiga Osservatorio made it possible to submit over 13,000 astrometric measurements of 3,500 asteroids, and we also reported 1,151 candidates for potentially unknown objects. During our presentation, we would like to introduce details of design and several enhancements to allow a convenient and safe way to control an observing session from anywhere in the world using a smartphone.

Zolnowski, M.; Kusiak, M.

2014-07-01

370

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

371

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

372

Optical design of the Big Bear Solar Observatory's multi-conjugate adaptive optics system  

NASA Astrophysics Data System (ADS)

A multi-conjugate adaptive optics (MCAO) system is being built for the world's largest aperture 1.6m solar telescope, New Solar Telescope, at the Big Bear Solar Observatory (BBSO). The BBSO MCAO system employs three deformable mirrors to enlarge the corrected field of view. In order to characterize the MCAO performance with different optical configurations and DM conjugated altitudes, the BBSO MCAO setup also needs to be flexible. In this paper, we present the optical design of the BBSO MCAO system.

Zhang, Xianyu; Gorceix, Nicolas; Schmidt, Dirk; Goode, Philip R.; Cao, Wenda; Rimmele, Thomas R.; Coulter, Roy

2014-07-01

373

SYSTEMATIC MOTION OF FINE-SCALE JETS AND SUCCESSIVE RECONNECTION IN SOLAR CHROMOSPHERIC ANEMONE JET OBSERVED WITH THE SOLAR OPTICAL TELESCOPE/HINODE  

SciTech Connect

The Solar Optical Telescope (SOT) on board Hinode allows observations with high spatiotemporal resolution and stable image quality. A {lambda}-shaped chromospheric anemone jet was observed in high resolution with SOT/Hinode. We found that several fine-scale jets were launched from one end of the footpoint to the other. These fine-scale jets ({approx}1.5-2.5 Mm) gradually move from one end of the footpoint to the other and finally merge into a single jet. This process occurs recurrently, and as time progresses the jet activity becomes more and more violent. The time evolution of the region below the jet in Ca II H filtergram images taken with SOT shows that various parts (or knots) appear at different positions. These bright knots gradually merge into each other during the maximum phase. The systematic motion of the fine-scale jets is observed when different knots merge into each other. Such morphology would arise due to the emergence of a three-dimensional twisted flux rope in which the axial component (or the guide field) appears in the later stages of the flux rope emergence. The partial appearance of the knots could be due to the azimuthal magnetic field that appears during the early stage of the flux rope emergence. If the guide field is strong and reconnection occurs between the emerging flux rope and an ambient magnetic field, this could explain the typical feature of systematic motion in chromospheric anemone jets.

Singh, K. A. P.; Nishida, K.; Shibata, K. [Kwasan and Hida Observatories, Graduate School of Science, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Isobe, H., E-mail: singh@kwasan.kyoto-u.ac.jp [Unit for Synergetic Study for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

2012-11-20

374

Telescope) Systems  

E-print Network

ABSTRACT. The PHOT (Portable High-Speed Occultation Telescope) systems were developed for the specific purpose of observing stellar occultations by solar system objects. Stellar occultations have unique observing constraints: they may only be observable from certain parts of the globe; they often require a rapid observing cadence; and they require accurate time-stamp information for each exposure. The PHOT systems consist of 14 inch telescopes, CCD cameras, camera mounting plates, GPS-based time standards, and data acquisition computers. The PHOT systems are similar in principle to the POETS systems (Portable Occultation, Eclipse, and Transit Systems), with the main differences being (1) different CCD cameras with slightly different specifications and (2) a standalone custom-built time standard used by PHOT, whereas POETS uses a commercial time standard that is controlled from a computer. Since 2005, PHOT systems have been deployed on over two-dozen occasions to sites in the US,

E. F. Young; L. A. Young; C. B. Olkin; M. W. Buie; K. Shoemaker; R. G. French; J. Regester

375

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

376

Golay3 sparse aperture systems designed on a spherical surface  

NASA Astrophysics Data System (ADS)

High resolution imaging from space telescope for surveillance and astrometry is currently limited by launch vehicles and systems cost. The weight of the telescope is one of major factors which limits the vehicles to be placed in orbit. Sparse aperture optical system uses a reduced aperture area to synthesize the optical performance of a filled aperture. It is more promising in virtue of its light weight, low cost and larger synthetic aperture. The sparse aperture optical system has two types, i.e. the multiple-mirror telescope (MMT) and the multiple-telescope telescope (MTT). A MMT of Golay3 sparse aperture optical system is investigated that three sub-mirrors are located on a spherical primary mirror. Three sub apertures of Golay3 are elliptic that in fact the circular sub-mirrors of spherical primary mirror are projected on the entrance pupil. The relationships between fill factor, radius of sub-mirrors and F number of the primary mirror are presented. The analytical formula is also completed, which shows that the maximum fill factor is limited by F number of the primary mirror. When the aperture radius is equal to curvature radius of the primary mirror approximately, the shape of sub-apertures exhibits to be elliptic obviously. The maximum fill factor reaches the largest one at that time. Modulation Transfer Function (MTF) of Golay3 system is studied. MTF is the correlation of three elliptic sub-apertures. The sub-MTFs are different from those of sub-mirrors located on a plane. The formula is verified by designing two Cassegrain telescopes which primary mirror is made up of three sub-mirrors of Golay3 configuration with Zemax optical program. Three sub-mirrors of primary mirror share a common asphercial secondary mirror. The errors caused by tilt and piston of three sub-apertures are also given out. Because of the loss of MTF for the sparse aperture optical system, the image quality is decreased. Wiener filter technique is utilized to improve the image quality for the sparse aperture system.

Wu, Feng; Wu, Quanying; Qian, Lin

2008-03-01

377

The Chromosphere above the sunspot umbra as seen in the New Solar Telescope and Interface Region Imaging Spectrograph  

NASA Astrophysics Data System (ADS)

Recent observations of sunspot's umbra suggested that it may be finely structured at a sub-arcsecond scale representing a mix of hot and cool plasma elements. In this study we report observations from the New Solar Telescope (NST) of the umbral spikes, which are cool jet-like structures seen in the chromosphere of an umbra. Our analysis indicates that the spikes are not associated with photospheric umbral dots and they tend to occur above darkest parts of the umbra, where magnetic fields are strongest. The spikes exhibit up and down oscillatory motions and their spectral evolution suggests that they might be driven by upward propagating shocks generated by photospheric oscillations.We analyze sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) data and narrow-band NST images and found long term variations in the intensity of chromospheric shocks. Also, sunspot umbral flashes (UFs) appear as narrow bright lanes running along the light bridges (LBs) and clusters of umbral dots (UDs). Time series suggested that UFs preferred to appear on the sunspot-center side of LBs, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. We find that the sunspot's umbra appears bright in IRIS images above LBs and UDs. Co-spatial and co-temporal SDO/AIA data showed that these locations were associated with bright footpoints of umbral loops suggesting that LBs may play an important role in heating these loops. The power spectra analysis showed that the intensity of umbral oscillations significantly varies 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, Vasyl; Goode, Phil; Abramenko, Valentyna; Kilcik, Ali

2015-04-01

378

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

379

The effect of synchronization errors on the performance of telescope arrays for optical deep space communications  

Microsoft Academic Search

Evolving optical deep space communication network architecture requires incremental growth in the total aperture. On the other hand, the cost of a large aperture telescope grows exponentially as a function of its diameter, therefore telescope array architecture could provide a cost effective scalable growth for an evolving optical deep space network. However, the total aperture size and the corresponding breakdown

Ali Asghar Eftekhar; Ali Javad Hashmi; Ali Adibi; Farid Amoozegar

2006-01-01

380

Next Generation Space Telescope  

NASA Technical Reports Server (NTRS)

The Next Generation Space Telescope (NGST), planned for launch in 2009, will be an 8-m class radiatively cooled infrared telescope at the Lagrange point L2. It will cover the wavelength range from 0.6 to 28 microns with cameras and spectrometers, to observe the first luminous objects after the Big Bang, and the formation, growth, clustering, and evolution of galaxies, stars, and protoplanetary clouds, leading to better understanding of our own Origins. It will seek evidence of the cosmic dark matter through its gravitational effects. With an aperture three times greater than the Hubble Space Telescope, it will provide extraordinary advances in capabilities and enable the discovery of many new phenomena. It is a joint project of the NASA, ESA, and CSA, and scientific operations will be provided by the Space Telescope Science Institute.

Mather, John; Stockman, H. S.; Fisher, Richard R. (Technical Monitor)

2000-01-01

381

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

382

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

383

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

384

Solar viewing interferometer prototype  

NASA Astrophysics Data System (ADS)

The Earth Atmospheric Solar-Occultation Imager (EASI) is a proposed interferometer with 5 telescopes on an 8-meter boom in a 1D Fizeau configuration. Placed at the Earth-Sun L2 Lagrange point, EASI would perform absorption spectroscopy of the Earth"s atmosphere occulting the Sun. Fizeau interferometers give spatial resolution comparable to a filled aperture but lower collecting area. Even with the small collecting area the high solar flux requires most of the energy to be reflected back to space. EASI will require closed loop control of the optics to compensate for spacecraft and instrument motions, thermal and structural transients and pointing jitter. The Solar Viewing Interferometry Prototype (SVIP) is a prototype ground instrument to study the needed wavefront control methods. SVIP consists of three 10 cm aperture telescopes, in a linear configuration, on a 1.2-meter boom that will estimate atmospheric abundances of O2, H2O, CO2, and CH4 versus altitude and azimuth in the 1.25 - 1.73 micron band. SVIP measures the Greenhouse Gas absorption while looking at the sun, and uses solar granulation to deduce piston, tip and tilt misalignments from atmospheric turbulence and the instrument structure. Tip/tilt sensors determine relative/absolute telescope pointing and operate from 0.43 - 0.48 microns to maximize contrast. Two piston sensors, using a robust variation of dispersed fringes, determine piston shifts between the baselines and operate from 0.5 - 0.73 microns. All sensors are sampled at 800 Hz and processed with a DSP computer and fed back at 200 Hz (3 dB) to the active optics. A 4 Hz error signal is also fed back to the tracking platform. Optical performance will be maintained to better than ?/8 rms in closed-loop.

Lyon, Richard G.; Herman, Jay R.; Abuhassan, Nader; Marx, Catherine T.; Kizhner, Semion; Crooke, Julie; Toland, Ronald W.; Mariano, Albert; Salerno, Cheryl; Brown, Gary; Cazeau, Tony; Petrone, Peter P., III; Mamakos, Billy; Tournois, Severine C.

2004-10-01

385

Opportunities for Follow-Up Observations of Solar System Objects with 50/70 cm Schmidt Telescope  

E-print Network

. Nevertheless, changes of observational schedules (especially for small telescopes) and observations of targets system is used for the observations. In addition we have opportunity to use narrowband filter set

Boyer, Edmond

386

Design of large aperture focal plane shutter  

NASA Astrophysics Data System (ADS)

To satisfy the requirement of large telescope, a large aperture focal plane shutter with aperture size of ?200mm was researched and designed to realize, which could be started and stopped in a relative short time with precise position, and also the blades could open and close at the same time at any orientation. Timing-belts and stepper motors were adopted as the drive mechanism. Velocity and position of the stepper motors were controlled by the PWM pulse generated by DSP. Exponential curve is applied to control the velocity of the stepper motors to make the shutter start and stop in a short time. The closing/open time of shutter is 0.2s, which meets the performance requirements of large telescope properly.

Hu, Jia-wen; Ma, Wen-li; Huang, Jin-long

2012-09-01

387

Large bearings with incorporated gears, high stiffness and precision for the Swedish Solar Telescope (SST) on La Palma  

E-print Network

. It consists of a relatively slender tower with on top only the vacuum turret for reflecting downward the solar downward into the tower. The solar image was formed in the basement of the tower by the lens on top. Near1 Large bearings with incorporated gears, high stiffness and precision for the Swedish Solar

Rutten, Rob

388

Solar Meridional Circulation from Doppler Shifts of the Fe I Line at 5250 Å as Measured by the 150-foot Solar Tower Telescope at the Mt. Wilson Observatory  

Microsoft Academic Search

Doppler shifts of the Fe I spectral line at 5250 Å 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

Roger K. Ulrich; Roger K

2010-01-01

389

Space and lunar-based optical telescopes  

NASA Technical Reports Server (NTRS)

The growth of space observatories, especially at optical wavelengths, during the next several decades is considered. It is concluded that large aperture optical telescopes on the Moon, possibly constructed of lunar glasses, will be very competitive with and in some instances superior to Earth orbiting telescopes.

Stockman, H. S.

1988-01-01

390

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

391

Compressed Synthetic Aperture Radar  

Microsoft Academic Search

In this paper, we introduce a new synthetic aperture radar (SAR) imaging modality which can provide a high-resolution map of the spatial distribution of targets and terrain using a significantly reduced number of needed transmitted and\\/or received electromagnetic waveforms. This new imaging scheme, requires no new hardware components and allows the aperture to be compressed. It also presents many new

Vishal M. Patel; Glenn R. Easley; Dennis M. Healy; Jr.

2010-01-01

392

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

393

Alignment telescope for Antares  

SciTech Connect

The Antares Automatic Alignment System employs a specially designed telescope for alignment of its laser beamlines. There are two telescopes in the system, and since each telescope is a primary alignment reference, stringent boresight accuracy and stability over the focus range were required. Optical and mechanical designs, which meet this requirement as well as that of image quality over a wide wavelength band, are described. Special test techniques for initial assembly and alignment of the telescope are also presented. The telescope, which has a 180-mm aperture FK51-KZF2 type glass doublet objective, requires a boresight accuracy of 2.8 ..mu..rad at two focal lengths, and object distances between 11 meters and infinity. Travel of a smaller secondary doublet provides focus from 11 m to infinity with approximately 7.8 m effective focal length. By flipping in a third doublet, the effective focal length is reduced to 2.5 m. Telescope alignment was accomplished by using a rotary air bearing to establish an axis in front of the system and placing the focus of a Laser Unequal Path Interferometer (LUPI) at the image plane.

Appert, Q.D.; Swann, T.A.; Ward, J.H.; Hardesty, C.; Wright, L.

1983-01-01

394

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

395

Sub-Aperture Interferometers  

NASA Technical Reports Server (NTRS)

Sub-aperture interferometers -- also called wavefront-split interferometers -- have been developed for simultaneously measuring displacements of multiple targets. The terms "sub-aperture" and "wavefront-split" signify that the original measurement light beam in an interferometer is split into multiple sub-beams derived from non-overlapping portions of the original measurement-beam aperture. Each measurement sub-beam is aimed at a retroreflector mounted on one of the targets. The splitting of the measurement beam is accomplished by use of truncated mirrors and masks, as shown in the example below

Zhao, Feng

2010-01-01

396

MEMS microshutter arrays for James Webb Space Telescope  

Microsoft Academic Search

MEMS microshutter arrays (MSAs) are being developed at NASA Goddard Space Flight Center for use as an aperture array for the Near-Infrared Spectrometer (NirSpec). The instruments will be carried on the James Webb Space Telescope (JWST), the next generation of space telescope after Hubble Space Telescope retires. The microshutter arrays are designed for the selective transmission of light with high

Mary J. Li; Tomoko Adachi; Christine Allen; Sachi Babu; Sateesh Bajikar; Michael Beamesderfer; Ruth Bradley; Kevin Denis; Nick Costen; Audrey Ewin; David Franz; Larry Hess; Ron Hu; Kamili M. Jackson; Murzy Jhabvala; Dan Kelly; Todd King; Gunther Kletetschka; Alexander Kutyrev; Barney Lynch; Timothy Miller; Harvey Moseley Jr.; Vilem Mikula; Brent Mott; Lance Oh; James T. Pontius; David Rapchun; Chris Ray; Eric Schulte; Scott Schwinger; Peter Shu; Robert Silverberg; Wayne Smith; Steve Snodgrass; David Sohl; Leroy Sparr; Rosalind Steptoe-Jackson; Valeriano Veronica; Liqin Wang; Yun Zheng; Chris Zincke

2007-01-01

397

Microshutter Array System for James Webb Space Telescope  

Microsoft Academic Search

We have developed microshutter array systems at NASA Goddard Space Flight Center for use as multi-object aperture arrays for a Near-Infrared Spectrometer (NIRSpec) instrument. The instrument will be carried on the James Webb Space Telescope (JWST), the next generation of space telescope, after the Hubble Space Telescope retires. The microshutter arrays (MSAs) are designed for the selective transmission of light

M. J. Li; T. Adachi; C. A. Allen; S. R. Babu; S. Bajikar; M. A. Beamesderfer; R. Bradley; N. P. Costen; Kevin Denis; A. J. Ewin; D. Franz; L. Hess; R. Hu; K. Jackson; M. D. Jhabvala; D. Kelly; G. Kletetschka; A. S. Kutyrev; B. A. Lynch; S. E. Meyer; T. Miller; S. H. Moseley; V. Mikula; B. Mott; L. Oh; J. T. Pontius; D. A. Rapchun; C. Ray; S. Schwinger; P. K. Shu; R. Silverberg; W. W. Smith; S. Snodgrass; D. Sohl; L. Sparr; R. Steptoe-Jackson; R. J. Thate; F. Wang; L. Wang; Y. Zheng; C. Zincke; Todd T. King

2007-01-01

398

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

399

The Pan-STARRS Survey Telescope Project  

NASA Astrophysics Data System (ADS)

The Institute for Astronomy at the University of Hawaii is developing a large optical/near-IR survey telescope system; the Panoramic Survey Telescope and Rapid Response System. Pan-STARRS will employ 1.8m optical imagers very large (7 square degree) field of view and revolutionary 1.4 billion pixel CCD cameras with low noise and rapid read-out to provide broad band imaging from 400-1000nm wavelength. The project is proceeding in two phases: PS1 is a single aperture system that has been deployed on Haleakala on Maui and the full 4-aperture system PS4 will be sited on Mauna Kea and is scheduled to become operational in late 2010. The data from Pan-STARRS will be reduced in near real time to produce both a cumulative image of the static sky and difference images, from which transient, moving and variable objects can be detected. Pan-STARRS will be able to scan the entire visible sky to approximately 24th magnitude in less than a week, and this unique combination of sensitivity and cadence will open up many new possibilities in time domain astronomy. A major goal for the project is to survey potentially dangerous asteroids, where Pan-STARRS will be able to detect most objects down to 300m size, much smaller than the km size objects accessible to existing search programs. In addition, the Pan-STARRS data will provide a dramatic leap in data quality and extent over existing wide-field image durvey data that will be used to advance our understanding of the formation of the Solar System, the Galaxy, and the Cosmos at large. In this talk I will describe the science drivers for the project; review the technical design and performance metrics for various scientific gols; and give an update on the current status and future time-line of the project.

Kaiser, N.

400

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

401

Variable-aperture screen  

DOEpatents

Apparatus is described 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. 10 figures.

Savage, G.M.

1991-10-29

402

Study of Rapid Formation of a Delta Sunspot Associated with the 2012 July 2 C7.4 Flare Using High-resolution Observations of New Solar Telescope  

E-print Network

Rapid, irreversible changes of magnetic topology and sunspot structure associated with flares have been systematically observed in recent years. The most striking features include the increase of horizontal field at the polarity inversion line (PIL) and the co-spatial penumbral darkening. A likely explanation of the above phenomenon is the back reaction to the coronal restructuring after eruptions: a coronal mass ejection carries the upward momentum while the downward momentum compresses the field lines near the PIL. Previous studies could only use low resolution (above 1") magnetograms and white-light images. Therefore, the changes are mostly observed for X-class flares. Taking advantage of the 0.1" spatial resolution and 15s temporal cadence of the New Solar Telescope at Big Bear Solar Observatory, we report in detail the rapid formation of sunspot penumbra at the PIL associated with the C7.4 flare on 2012 July 2. It is unambiguously shown that the solar granulation pattern evolves to alternating dark and b...

Wang, Haimin; Wang, Shuo; Deng, Na; Xu, Yan; Jing, Ju; Cao, Wenda

2013-01-01

403

Implications of Ultraviolet Imaging Telescope observations for star formation histories in NGC 1275  

NASA Technical Reports Server (NTRS)

We discuss UV imagery of NGC 1275 obtained using the Goddard Ultraviolet Imaging Telescope. We are able to study the UV morphology down to mu 249 of about 25 mag/sq arcsec. There are significant nonaxisymmetric structures in the UV continuum associated with the low-velocity filament system. Continuum from the high-velocity system may also be present. The large aperture UV colors indicate that although the mass function extends to about 5 solar masses, more massive objects are not present. This implies either a cessation of star formation during the last 50-100 Myr or a truncated initial mass function.

Smith, Eric P.; O'Connell, Robert W.; Bohlin, Ralph C.; Cheng, Kwang-Ping; Cornett, Robert H.; Hill, Jesse K.; Hill, Robert S.; Hintzen, Paul; Landsman, Wayne B.; Neff, Susan G.

1992-01-01

404

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

405

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

406

High-energy Gamma-Ray Emission from Solar Flares: Summary of Fermi Large Area Telescope Detections and Analysis of Two M-class Flares  

NASA Astrophysics Data System (ADS)

We present the detections of 18 solar flares detected in high-energy ?-rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first 4 yr of operation. This work suggests that particle acceleration up to very high energies in solar flares is more common than previously thought, occurring even in modest flares, and for longer durations. Interestingly, all these flares are associated with fairly fast coronal mass ejections (CMEs). We then describe the detailed temporal, spatial, and spectral characteristics of the first two long-lasting events: the 2011 March 7 flare, a moderate (M3.7) impulsive flare followed by slowly varying ?-ray emission over 13 hr, and the 2011 June 7 M2.5 flare, which was followed by ?-ray emission lasting for 2 hr. We compare the Fermi LAT data with X-ray and proton data measurements from GOES and RHESSI. We argue that the ?-rays are more likely produced through pion decay than electron bremsstrahlung, and we find that the energy spectrum of the proton distribution softens during the extended emission of the 2011 March 7 flare. This would disfavor a trapping scenario for particles accelerated during the impulsive phase of the flare and point to a continuous acceleration process at play for the duration of the flares. CME shocks are known for accelerating the solar energetic particles (SEPs) observed in situ on similar timescales, but it might be challenging to explain the production of ?-rays at the surface of the Sun while the CME is halfway to the Earth. A stochastic turbulence acceleration process occurring in the solar corona is another likely scenario. Detailed comparison of characteristics of SEPs and ?-ray-emitting particles for several flares will be helpful to distinguish between these two possibilities.

Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Bonamente, E.; Bottacini, E.; Bouvier, A.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chen, Q.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Desiante, R.; Digel, S. W.; Di Venere, L.; Silva, E. do Couto e.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Inoue, Y.; Jackson, M. S.; Jogler, T.; Jóhannesson, G.; Johnson, W. N.; Kamae, T.; Kawano, T.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Murphy, R.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Perkins, J. S.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Ritz, S.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Takahashi, H.; Takeuchi, Y.; Tanaka, Y.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tinivella, M.; Tosti, G.; Troja, E.; Tronconi, V.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Werner, M.; Winer, B. L.; Wood, D. L.; Wood, K. S.; Wood, M.; Yang, Z.

2014-05-01

407

Hubble Space Telescope Optical Telescope Assembly  

NASA Technical Reports Server (NTRS)

This image illustrates the Hubble Space Telescope's (HST's) Optical Telescope Assembly (OTA). One of the three major elements of the HST, the OTA consists of two mirrors (a primary mirror and a secondary mirror), support trusses, and the focal plane structure. The mirrors collect and focus light from selected celestial objects and are housed near the center of the telescope. The primary mirror captures light from objects in space and focuses it toward the secondary mirror. The secondary mirror redirects the light to a focal plane where the Scientific Instruments are located. The primary mirror is 94.5 inches (2.4 meters) in diameter and the secondary mirror is 12.2 inches (0.3 meters) in diameter. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth Orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from the Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The spacecraft is 42.5 feet (13 meters) long and weighs 25,000 pounds (11,600 kilograms). The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

1986-01-01

408

A study of the solar daily variation of meson intensity at Ahmedabad (? = 13° N) using a cubical meson telescope  

Microsoft Academic Search

Conclusions  The main points which emerge from the present study may be summarised as follows:\\u000a \\u000a \\u000a 1. \\u000a During the period June 1955 to November 1955 the mean daily variation of meson intensity, corrected for the daily variation\\u000a of barometric pressure, as measured by the cubical meson telescope is mainly diurnal in character with an amplitude of (0·3\\u000a ± 0·01%) and time of

Krishna Ramanathan

1956-01-01

409

Telescopic limiting magnitudes  

NASA Technical Reports Server (NTRS)

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

Schaefer, Bradley E.

1990-01-01

410

KAOS: kilo-aperture optical spectrograph  

NASA Astrophysics Data System (ADS)

A design is described for a potential new facility capable of taking detailed spectroscopy of millions of objects in the Universe to explore the complexity of the Universe and to answer fundamental questions relating to the equation of state of dark energy and to how the Milky Way galaxy formed. The specific design described is envisioned for implementation on the Gemini 8-meter telescopes. It utilizes a 1.5° field of view and samples that field with up to ~5000 apertures. This Kilo-Aperture Optical Spectrograph (KAOS) is mounted at prime focus with a 4-element corrector, atmospheric dispersion compensator (ADC), and an Echidna-style fiber optic positioner. The ADC doubles as a wobble plate, allowing fast guiding that cancels out the wind buffeting of the telescope. The fibers, which can be reconfigured in less than 10 minutes, feed to an array of 12 spectrographs located in the pier of the telescope. The spectrographs are capable of provided spectral resolving powers of a few thousand up to about 40,000.

Barden, Samuel C.; Dey, Arjun; Boyle, Brian; Glazebrook, Karl

2004-09-01

411

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

412

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

413

Optimum synthetic-aperture imaging of extended astronomical objects.  

PubMed

In optical aperture-synthesis imaging of stellar objects, different beam combination strategies are used and proposed. Coaxial Michelson interferometers are very common and a homothetic multiaxial interferometer is recently realized in the Large Binocular Telescope. Laboratory experiments have demonstrated the working principles of two new approaches: densified pupil imaging and wide field-of-view (FOV) coaxial imaging using a staircase-shaped mirror. We develop a common mathematical formulation for direct comparison of the resolution and noise sensitivity of these four telescope configurations for combining beams from multiple apertures for interferometric synthetic aperture, wide-FOV imaging. Singular value decomposition techniques are used to compare the techniques and observe their distinct signal-to-noise ratio behaviors. We conclude that for a certain chosen stellar object, clear differences in performance of the imagers are identifiable. PMID:17361290

van der Avoort, Casper; Pereira, Silvania F; Braat, Joseph J M; den Herder, Jan-Willem

2007-04-01

414

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

415

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

416

A fast, wide field of view, catadioptric telescope for Whipple  

NASA Astrophysics Data System (ADS)

We describe the optical design of a spaceborne f/1.3 catadioptric telescope with a 9 degree field and 77 cm aperture that is being proposed to study objects in the Kuiper belt, Sedna Region, and Oort cloud.

McGuire, James P.

2014-12-01

417

Laser guide star projection for large telescopes Erez N. Ribak  

E-print Network

beam diameter is set by the turbulence distorting the beam going up. Most systems use the light is large, then even for 8 m telescopes and side-mounted laser launchers, the opposite side of the aperture

Ribak, Erez

418

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

419

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

420

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