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 Haleakalā 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.
KEYWORDS: Telescopes, Mirrors, Control systems, Magnetism, Solar telescopes, Space telescopes, Optical fabrication, Solar processes, Visible radiation, Observatories
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.
The NASA Interface Region Imaging Spectrograph (IRIS) mission is a Small Explorer (SMEX) satellite mission
designed to study plasma dynamics in the “interface region” between the Sun’s chromosphere and corona with high
spatial, spectral, and temporal resolution. The primary instrument is a dual Czerny-Turner spectrograph fed by a 20-cm
Cassegrain telescope measuring near- and far-ultraviolet (NUV, FUV) spectral lines in the ranges 133-141 nm and 278-
283 nm. To determine the position of the slit on the solar disk, a slit-jaw imaging system is used. The NUV slit-jaw
imaging system produces high spatial resolution images at two positions in the Mg II 280 nm spectral line complex using
a birefringent Solc filter with two wide-band interference pre-filters for spectral order selection. The Solc filter produces
a 0.36 nm full-width at half-maximum (FWHM) filter profile with low sidelobes and a peak transmission of 15% at
279.6 nm. The filter consists of two “wire grid’’ polarizers surrounding 8 quartz waveplates configured in a modified
Solc “fan” rotational pattern. The elements are optically coupled using DC200 silicon-based grease. The NUV Solc filter
is sealed in a windowed cell to prevent silicon contamination of the FUV channel. The design of the sealed cell and
assembly of the filter into the cell were among the most challenging optomechanical aspects of the IRIS spectrograph
system.
The Interface Region Imaging Spectrograph (IRIS) is a NASA SMall EXplorer mission scheduled for launch in January
2013. The primary goal of IRIS is to understand how the solar atmosphere is energized. The IRIS investigation
combines advanced numerical modeling with a high resolution UV imaging spectrograph. IRIS will obtain UV spectra
and images with high resolution in space (0.4 arcsec) and time (1s) focused on the chromosphere and transition region of
the Sun, a complex interface region between the photosphere and corona. The IRIS instrument uses a Cassegrain
telescope to feed a dual spectrograph and slit-jaw imager that operate in the 133-141 nm and 278-283 nm ranges. This
paper describes the instrument with emphasis on the imaging spectrograph, and presents an initial performance
assessment from ground test results.
This poster outlines the conceptual design of the Visible-light Broad-band Imager (VBI) instrument for the Advanced Technology Solar Telescope (ATST) as it follows from scientific requirements. The VBI is scheduled to be the first-light instrument of the ATST, highlighting the telescope's high spatial resolution capabilities.
The 4-m aperture Advanced Technology Solar Telescope (ATST) is the next generation ground based solar telescope. In this paper we provide an overview of the ATST post-focus instrumentation. The majority of ATST instrumentation is located in an instrument Coude lab facility, where a rotating platform provides image de-rotation. A high order adaptive optics system delivers a corrected beam to the Coude lab facility. Alternatively, instruments can be mounted at Nasmyth or a small Gregorian area. For example, instruments for observing the faint corona preferably will be mounted at Nasmyth focus where maximum throughput is achieved. In addition, the Nasmyth focus has minimum telescope polarization and minimum stray light. We describe the set of first generation instruments, which include a Visible-Light Broadband Imager (VLBI), Visible and Near-Infrared (NIR) Spectropolarimeters, Visible and NIR Tunable Filters, a Thermal-Infrared Polarimeter & Spectrometer and a UV-Polarimeter. We also discuss unique and efficient approaches to the ATST instrumentation, which builds on the use of common components such as detector systems, polarimetry packages and various opto-mechanical components.
Bruce Lites, David Elmore, Kim Streander, David Akin, Tom Berger, Dexter Duncan, Chris Edwards, Barbara Francis, Chris Hoffmann, Noah Katz, Michael Levay, Dnyanesh Mathur, William Rosenberg, Ericka Sleight, Theodore Tarbell, Alan Title, Darrel Torgerson
As a Japanese National space mission with international collaboration, Solar-B (2005 launch) will carry a spectro- polarimeter (SP) to be operated in visible light to obtain the first high angular resolution, precision measurements of solar vector magnetic fields from space. The SP is part of the Focal Plane Package (FPP) fed by a diffraction-limited 50-cm optical telescope. The SP will be operated exclusively at the photospheric 630 nm Fe I lines. It features a rotating, low-order crystalline quartz retarder for polarization modulation and a reflecting Littrow spectrograph design that is shortened by using diffraction from the 12micrometers wide slit to fill the grating. Polarization analysis is accomplished by a modified Savart plate beam splitter. A custom CCD detector with two active areas, one for each beam from the beam splitter, allows continuous high duty-cycle sampling of polarization. The spectrograph slit will sample a 0.16 x 164 arcsec2 rectangle of the solar image, which may be scanned across the slit by up to +/- 160 arcsec in order to build up vector magnetic field maps of the solar photosphere. Along with simultaneous, co-spatial imaging and polarimetry with the filter imagers of the FPP, the SP will provide a precise view of active and quiet solar magnetic fields that control the structure, dynamics, and energetics of the upper solar atmosphere.
Clarence Korendyke, A. Vourlidas, John Cook, Kenneth Dere, R. Feldman, Russell Howard, D. Lilley, Jeff Morrill, J. Daniel Moses, Norman Moulton, Robert Moye, D. Roberts, E. Shepler, J. Smith, Dennis Socker, T. Spears, R. Waymire, Wayne Brown, Theodore Tarbell, Tom Berger, Brian Handy
The Very high Angular Resolution ULtraviolet Telescope experiment was successfully launched on May 7, 1999 on a Black Brant sounding rocket vehicle from White Sands Missile Range. The instrument consists of a 30 cm UV diffraction limited telescope followed by a double grating spectroheliograph tuned to isolate the solar Lyman (alpha) emission line. During the flight, the instrument successfully obtained a series of images of the upper chromosphere with a limiting resolution of approximately 0.33 arc-seconds. The resulting observations are the highest resolution images of the solar atmosphere obtained from space to date. The flight demonstrated that subarc-second ultraviolet images of the solar atmosphere are achievable with a high quality, moderate aperture space telescope and associated optics. Herein, we describe the payload and its in- flight performance.
We have designed and fabricated a high-vacuum facility for the detailed characterization of the Multi-Anode Microchannel Array (MAMA) detector systems at Extreme Ultraviolet and Far Ultraviolet wavelengths between about 300 angstroms and 3000 angstroms. The first task for this facility is the characterization of the MAMA detectors for the European Space Agency/NASA Solar and Heliosphere Observatory (SOHO) mission. This paper describes the different configurations of the characterization facility and outlines the SOHO MAMA characterization procedures.
We have initiated the characterizations of the Multi-Anode Microchannel Array (MAMA) detector systems for the European Space Agency/NASA Solar and Heliospheric Observatory (SOHO) mission. In this paper we briefly review the configurations of the SOHO MAMA detectors and describe their expected performance characteristics based on the results of characterizations of the curved-channel microchannel plates and of the initial characterization of the first engineering model detector system for the Solar Ultraviolet Measurements of Emitted Radiation instrument.
The evaluation of the performances of a toroidal grating for the high-resolution EUV spectroheliometer (HiRES) has been realized. This is a holographically ruled grating operating in a normal incidence Rowland configuration at the 510 - 630 angstroms spectral range. An analysis of the grating resolution performances has been realized by means of a scintillator- intensifier-CCD detector showing very good results. Also a measurement of the grating diffraction efficiency has been performed, showing on the contrary a value lower than the predicted one.
The HiRES sounding rocket payload has been described in detail in previous SPIE Proceedings. Here, optical design of the toroidal grating spectrograph is presented and discussed. Ray tracing results are presented which outline the extreme ultraviolet (EUV) performance theoretically attainable with the HiRES instrument. Effects of optical system misalignment on the spectrograph image quality are investigated. Laboratory test results of two f/15 toroidal diffraction gratings using a 1 meter vacuum spectrograph and a multi-anode microchannel array detector are presented and discussed. The test toroidal gratings are fabricated using the elastic substrate replication technique from a ruled master grating with either a 3600 lines/mm or 1800 lines/mm density. EUV images of 10 25 micrometers pinholes with 250 micrometers center-to-center spacing taken with a hollow cathode discharge lamp are presented. Interferometric studies of toroidal figure accuracy as well as optical and electron microscopy investigations into surface quality are presented and discussed. It is found that the current toroidal gratings exhibit good imaging characteristics across a wide wavelength range but suffer from excessive EUV scatter and spectral ghosting.
The measurement of the shape and optical performance of toroidal mirrors has always presented a challenge to the manufacturer and user of these types of optical elements. This report presents a technique for evaluating the complex shape and optical performance of long radius toroidal mirrors that are to be used in the EUV. The measurement techniques will be discussed and examples given. Interferometric analysis will be presented. Performance spot diagrams and MTF analysis will be discussed. Manufacturing techniques will be evaluated with respect to the application of more definitive measurement technology.
The HiRES High-Resolution EUV Spectroheliometer is a sounding rocket instrument yielding very high spatial, spectral, and temporal resolution images of the solar outer atmosphere, on the basis of a 45-cm Gregorian telescope feeding a normal-incidence stigmatic EUV spectrometer with imaging multianode microchannel-array detector system, as well as an IR spectrometer with imaging CCD detector system. Attention is given to the expected performance of this system, including the effects of vibrational misalignments due to the sounding rocket flight environment.
We describe the design of a high-resolution stigmatic extremeultraviolet (EUV) spectroheliometer, configured for flight on a Black Brant sounding rocket, which consists of a 45-cm Gregory telescope coupled to a spectrometer employing a single toroidal diffraction grating in a normalincidence Rowland circle mounting and an imaging pulse-counting multianode microchannel array (MAMA) detector system. The toroidal diffraction grating is fabricated by a technique employing an elastically deformable submaster grating that is replicated in a spherical form and then mechanically distorted to produce the desired aspect ratio of the toroidal surface for stigmatic imaging over the selected wavelength range. The spectroheliometer will produce spatially resolved spectra of the chromosphere, transition region, and corona with an angular resolution of 0.4 arcsec or better, a spectral resolution λ/Δλ of about 104 in first order, and a temporal resolution of the order of seconds. Because of the geometric fidelity of the MAMA detector system, the spectroheliometer will be able to determine Doppler shifts to a resolution of at least 2 mÅ at wavelengths near 600 Å (~1.0 km s-1), depending on the level of the accumulated signal. The unique characteristics of the spectroheliometer will be used in combination with plasma-diagnostic techniques to study the emperature, density, and velocity structures of specific features in the solar outer atmosphere.
We describe the design of a high-resolution stigmatic extreme-ultraviolet (EUV) spectroheliometer, configured for flight on a
Black Brant sounding rocket, which consists of a 45-cm Gregory telescope coupled to a spectrometer employing a single
toroidal diffraction grating in a normal-incidence Rowland circle mounting and an imaging pulse-counting Multi-Anode
Microchannel Array (MAMA) detector system. The toroidal diffraction grating is fabricated by a new technique employing an
elastically-deformable sub-master grating which is replicated in a spherical form and then mechanically distorted to produce the
desired aspect ratio of the toroidal surface for stigmatic imaging over the selected wavelength range. The spectroheliometer will
produce spatially-resolved spectra of the chromosphere, transition-region and corona with an angular resolution of 0.4 arc sec or
better, a spectral resolution AII of about 1O in first order, and a temporal resolution of the order of seconds. Because of the
geometric fidelity of the MAMA detector system, the speciroheliometer will be able to determine Doppler shifts to a resolution
of at least 2 mA at wavelengths near 600 A (-1.0 km s1), depending on the level of the accumulated signal. The unique
characteristics of the spectroheliometer will be used in combination with plasma-diagnostic techniques to study the temperature,
density and velocity structures of specific features in the solar outer atmosphere.
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