The Keck Adaptive Secondary Mirror (KASM) project is planned as a core component of adaptive optics (AO) improvements for the Keck 1 telescope. KASM will provide image quality enhancements to all instrument locations, while also enabling correction of the ground layer turbulence for wide field instruments, and the foundation for a visible light diffraction-limited AO system. KASM is intended to replace the original telescope secondary mirror (M2) and will support both adaptive optics correction and purely passive (seeing-limited) observing modes of operation. The concept for KASM has been developed considering both voice coil and hybrid variable reluctance actuator technology. A metrology and calibration setup for off-sky use has been developed to verify KASM performance both prior to installation and once at the telescope.
The Keck Adaptive Secondary Mirror (KASM) project will broaden the use of adaptive optics on the Keck I telescope by integrating the correction device into the secondary mirror. By replacing the static secondary with a high-actuator count convex deformable mirror, image sharpening will be available to all instrument ports. The KASM optical surface will be a thin shell polished to match the optical prescription of the existing Keck I secondary mirror to within a few microns. The final correction of the optical shape will be achieved with control of the ASM’s actuators. The calibration and verification equipment (CAVE) will be an optical metrology package designed to verify that the delivered KASM has the correct optical figure. CAVE will also be used to verify and calibrate the actuator motion, both spatially and temporally, forming the basis for the actuator influence functions used in closed-loop operations. CAVE will be used during testing at the University of California Observatories optical laboratory, as well as during commissioning and periodic verification at the W.M. Keck Observatory, necessitating a robust and repeatable kinematic mounting arrangement. We describe the design of CAVE and develop a concept for laboratory and telescope facility operations and calibration.
The SCALES instrument being developed at UC Observatories is designed to take spectra of directly imaged exoplanets in the thermal infrared (1-5 microns). The ability to switch from science imaging mode to pupil imaging mode to taking spectra at specific wavelengths requires precision mechanical subsystems to enable these different modes of operation at cryogenic temperatures. In this paper we discuss the design of a rotary stage that can position different Lyot masks, as well as different high precision metal optics to enable some of the broad functionality of SCALES. We will also review some of the analysis involved with validating the design, and specifics pertaining to the design of the precision mirrors mounted to this stage.
Since the start of science operations in 1993, the twin 10-meter W. M. Keck Observatory (WMKO) telescopes have continued to maximize their scientific impact to produce transformative discoveries that keep the U.S. observing community on the frontiers of astronomical research. Upgraded capabilities and new instrumentation are provided though collaborative partnerships primarily with the Caltech and University of California instrument development teams and through additional collaborations with the University of Notre Dame, the University of Hawaii, Swinburne University of Technology, industry, and other organizations. This paper summarizes the status and performance of observatory infrastructure projects, technology upgrades, and new additions to the suite of observatory instrumentation. We also provide a status of instrumentation projects in early and advanced stages of development that will achieve the goals and objectives summarized in the 2023 Keck Observatory strategic plan. Developed in collaboration with the WMKO science community, the Keck strategic plan sets our sites on 2035 and meets goals identified in the Astro2020 Decadal Survey.
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, echelle spectrometer that specializes in the discovery and characterization of exoplanets using Doppler spectroscopy. In designing KPF, the guiding principles were high throughput to promote survey speed and access to faint targets, and high stability to keep uncalibrated systematic Doppler measurement errors below 30 cm s−1. KPF achieves optical illumination stability with a tip-tilt injection system, octagonal cross-section optical fibers, a double scrambler, and active fiber agitation. The optical bench and optics with integral mounts are made of Zerodur to provide thermo-mechanical stability. The spectrometer includes a slicer to reformat the optical input, green and red channels (445–600 nm and 600–870 nm), and achieves a resolving power of ∼97,000. Additional subsystems include a separate, medium-resolution UV spectrometer (383–402 nm) to record the Ca II H & K lines, an exposure meter for real-time flux monitoring, a solar feed for sunlight injection, and a calibration system with a laser frequency comb and etalon for wavelength calibration. KPF was installed and commissioned at the W. M. Keck Observatory in late 2022 and early 2023 and is now in regular use for scientific observations. This paper presents an overview of the as-built KPF instrument and its subsystems, design considerations, and initial on-sky performance.
Since the start of science operations in 1993, the twin 10-meter W. M. Keck Observatory (WMKO) telescopes have continued to maximize their scientific impact and to produce transformative discoveries that keep the observing community on the frontiers of astronomical research. Upgraded capabilities and new instrumentation are provided though collaborative partnerships with Caltech, the University of California, and the University of Hawaii instrument development teams, as well as industry and other organizations. This paper summarizes the performance of recently commissioned infrastructure projects, technology upgrades, and new additions to the suite of observatory instrumentation. We also provide a status of projects currently in design or development phases and, since we keep our eye on the future, summarize projects in exploratory phases that originate from our 2022 strategic plan developed in collaboration with our science community to adapt and respond to evolving science needs.
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development at the UC Berkeley Space Sciences Laboratory for the W.M. Keck Observatory. KPF is designed to characterize exoplanets via Doppler spectroscopy with a goal of a single measurement precision of 0.3 m s-1 or better, however its resolution and stability will enable a wide variety of astrophysical pursuits. Here we provide post-preliminary design review design updates for several subsystems, including: the main spectrometer, the fabrication of the Zerodur optical bench; the data reduction pipeline; fiber agitator; fiber cable design; fiber scrambler; VPH testing results and the exposure meter.
We investigate an image slicer module for an optical multiobject spectrograph, wide-field optical spectrograph (WFOS), which is one of the first-light instruments of the Thirty Meter Telescope (TMT). The image slicer divides the target image into three slices, thus providing a one-third narrower slit width. By positioning a suite of such modules at the telescope focal surface, multiobject spectroscopy with high spectral resolution can be achieved. Three optical designs are developed: a two-mirror design, a four-mirror design, and a flat-mirror design. Comparing them, the flat-mirror design is found to be the most preferable for WFOS. From a tolerance analysis, the tolerances of manufacturing and assembling appear challenging but not insurmountable. We describe how the steep field curvature of TMT requires at least nine module variants, tuned to reduce defocus in specific focal surface zones. Finally, we introduce a viable mechanical packaging concept.
The Wide Field Optical Spectrometer (WFOS) is a seeing limited, multi-object spectrograph and first light instrument for the Thirty Meter Telescope (TMT) scheduled for first observations in 2027. The spectrograph will deliver a minimum resolution of R~5,000 over a simultaneous wavelength range of 310 nm to 1,000 nm with a multiplexing goal of between 20 and 700 targets. The WFOS team consisting of partners in China, India, Japan, and the United States has completed a trade study of two competing concepts intended to meet the design requirements derived from the WFOS detailed science case. The first of these design concepts is a traditional slit mask instrument capable of delivering R~1,000 for up to 100 simultaneous targets using 1 x 7 arc second slits, and a novel focal plane slicing method for R~5,000 on up to 20 simultaneous targets can be achieved by reformatting the 1 arc-second wide slits into three 0.3 arc-second slits projected next to each other in the spatial direction. The second concept under consideration is a highly multiplexed fiber based system utilizing a robotic fiber positioning system at the focal plane containing 700 individual collectors, and a cluster of up to 12 replicated spectrographs with a minimum resolution of R~5,000 over the full pass band. Each collecting element will contain a bundle of 19 fibers coupled to micro-lens arrays that allow for contiguous coverage of targets and adaptation of the f/15 telescope beam to f/3.2 for feeding the fiber system. This report describes the baseline WFOS design, provides an overview of the two trade study concepts, and the process used to down-select between the two options. Also included is a risk assessment regarding the known technical challenges in the selected design concept.
The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA), project has been operating airborne astronomy flights from Palmdale, California since 2011. The observatory consists of a modified 747-SP aircraft with a 2.5-meter telescope in its aft section. SOFIA has a suite of eight science instruments spanning visible to far-infrared wavelengths. For the majority of the year SOFIA operates out of the Armstrong Flight Research Center in Palmdale, California, giving access to Northern Hemisphere targets. SOFIA’s mobility also allows observations in the Southern Hemisphere (Christchurch, New Zealand), of objects such as the Large and Small Magellanic Clouds, the Galactic Center, and Eta Carinae In 2016, SOFIA added polarimetry capability on SOFIA, with HAWC+ commissioning flights. Selected science results, current instrument suite status, new capabilities, and some expectations of future instrument developments over the lifetime of the observatory will be discussed.
FIFI-LS (the Field Imaging Far Infrared Line Spectrometer for SOFIA) was successfully commissioned in 2014 during six flights on SOFIA. The observed wavelengths are set by rotating reflective gratings. In flight these gratings and their rotating mechanisms are exposed to vibrations. To quantify these vibrations, an acceleration sensor was placed on the exterior of the instrument. Simultaneously, the angle sensor of the grating was read out to analyze the movement of the grating. Based on this data, lab measurements were conducted to evaluate the effect of the vibrations on the image quality of FIFI-LS. The submitted paper will present the measured data and show the results of the analysis.
The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA), project has been operating airborne astronomy flights from Palmdale, California since 2011. The observatory consists of a modified 747sp aircraft with a 2.5meter telescope in the tail section. In addition to observing flights out of Palmdale, Ca. this airborne observatory has been able to take advantage of its mobility to observe in the southern hemisphere (New Zealand), to perform multi-wavelength observations of the Super Novae (SN 2014b) in 2014, and to intersect the track of a Pluto Occultation in the southern hemisphere just a few weeks prior to the New Horizons mission fly by of the planet in summer 2015. Science results, observatory operations, current instrument status and participation in future instrument developments, over the lifetime of the observatory will be discussed.
KEYWORDS: Exoplanets, Observatories, Photometry, Stars, Data modeling, Infrared astronomy, Rayleigh scattering, Signal to noise ratio, Point spread functions, Planets
Here, we report on the first successful exoplanet transit observation with the Stratospheric Observatory for Infrared Astronomy (SOFIA). We observed a single transit of the hot Jupiter HD 189733 b, obtaining two simultaneous primary transit lightcurves in the B and z′ bands as a demonstration of SOFIA’s capability to perform absolute transit photometry. We present a detailed description of our data reduction, in particular, the correlation of photometric systematics with various in-flight parameters unique to the airborne observing environment. The derived transit depths at B and z′ wavelengths confirm a previously reported slope in the optical transmission spectrum of HD 189733 b. Our results give new insights to the current discussion about the source of this Rayleigh scattering in the upper atmosphere and the question of fixed limb darkening coefficients in fitting routines.
The Field-Imaging Far-Infrared Line-Spectrometer (FIFI-LS) entered service on the Stratospheric Observatory for
Infrared Astronomy (SOFIA) on March 2014.
Exact pointing of the instrument is important. The SOFIA telescope provides an absolute pointing stability of 1” rms,
which is sufficient for FIFI-LS. The instrument boresight relative to the telescope reference system is established with
accuracy better than 1”. FIFI-LS has a built-in rotating K-Mirror to derotate the instrument field of view. Perfect
alignment of the optical axis of the K-Mirror and the optical axis of the optical systems in both instrument channels is
practically impossible. The remaining offsets result in a dependence of the instrument boresight on the K-Mirror
position. Therefore a boresight calibration model is established for each channel. With these models the instrument
boresight is calculated and transferred to the telescope control software. Achieving precise calibration of the boresight
has been an ongoing process including the first optical models of the instrument, measurements in different laboratories
and finally measurements during the commissioning flight series. In this paper, the approach used to calibrate FIFI-LS’s
boresight is explained. This includes the model used and an overview of the laboratory, as well as the in-flight
measurements leading to the calibrated boresight model.
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is the world’s largest airborne observatory, featuring a
2.5 meter effective aperture telescope housed in the aft section of a Boeing 747SP aircraft. SOFIA’s current instrument
suite includes: FORCAST (Faint Object InfraRed CAmera for the SOFIA Telescope), a 5-40 μm dual band
imager/grism spectrometer developed at Cornell University; HIPO (High-speed Imaging Photometer for Occultations), a
0.3-1.1μm imager built by Lowell Observatory; GREAT (German Receiver for Astronomy at Terahertz Frequencies), a
multichannel heterodyne spectrometer from 60-240 μm, developed by a consortium led by the Max Planck Institute for
Radio Astronomy; FLITECAM (First Light Infrared Test Experiment CAMera), a 1-5 μm wide-field imager/grism
spectrometer developed at UCLA; FIFI-LS (Far-Infrared Field-Imaging Line Spectrometer), a 42-200 μm IFU grating
spectrograph completed by University Stuttgart; and EXES (Echelon-Cross-Echelle Spectrograph), a 5-28 μm highresolution
spectrometer designed at the University of Texas and being completed by UC Davis and NASA Ames
Research Center. HAWC+ (High-resolution Airborne Wideband Camera) is a 50-240 μm imager that was originally
developed at the University of Chicago as a first-generation instrument (HAWC), and is being upgraded at JPL to add
polarimetry and new detectors developed at Goddard Space Flight Center (GSFC). SOFIA will continually update its
instrument suite with new instrumentation, technology demonstration experiments and upgrades to the existing
instrument suite. This paper details the current instrument capabilities and status, as well as the plans for future
instrumentation.
We present a status report and early commissioning results for FLITECAM, the 1-5 micron imager and spectrometer for
SOFIA (the Stratospheric Observatory for Infrared Astronomy). In February 2014 we completed six flights with
FLITECAM mounted in the FLIPO configuration, a co-mounting of FLITECAM and HIPO (High-speed Imaging
Photometer for Occultations; PI Edward W. Dunham, Lowell Observatory). During these flights, the FLITECAM modes
from ~1-4 μm were characterized. Since observatory verification flights in 2011, several improvements have been made
to the FLITECAM system, including the elimination of a light leak in the FLITECAM filter wheel enclosure, and
updates to the observing software. We discuss both the improvements to the FLITECAM system and the results from the
commissioning flights, including updated sensitivity measurements. Finally, we discuss the utility of FLITECAM in the
FLIPO configuration for targeting exoplanet transits.
FIFI-LS is the German far-infrared integral field spectrometer for the SOFIA airborne observatory. The instrument offers
medium resolution spectroscopy (R ~ a few 1000) in the far-infrared with two independent spectrometers covering 50-110
and 100-200 μm. The integral field units of the two spectrometers obtain spectra covering concentric square fields-of-views
sized 3000and 6000, respectively. Both spectrometers can observe simultaneously at any wavelength in their ranges making
efficient mapping of far-infrared lines possible.
FIFI-LS has been commissioned at the airborne observatory SOFIA as a PI instrument in spring 2014. During 2015,
the commissioning as facility instrument will be complete and the SOFIA observatory will take over the operation of
FIFI-LS. The instrument can already be used by the community. Primary science cases are the study of the galactic and
extra-galactic interstellar medium and its processes.
In this presentation, the capabilities of FIFI-LS on the SOFIA telescope will be explained and how they are used by the
offered observing modes. The remaining atmosphere and the warm telescope create a high background situation, which
requires a differential measurement technique. This is achieved by SOFIA’s chopping secondary mirror and nodding the
telescope. Depending on the source size, different observing modes may be used to observe a source. All modes use spatial
and spectral dithering. The resulting data products will be 3D-data cubes.
The observing parameters will be specified using AOTs, like the other SOFIA instruments, and created via the tool
SSPOT which is similar to the Spitzer Space Telescope SPOT tool. The observations will be done in service mode, but
SOFIA invites a few investigators to fly onboard SOFIA during (part of) their observations.
The Field Imaging Far Infrared Line Spectrometer (FIFI-LS) obtains spectral data within two wavelength ranges. The observed wavelengths are set by rotating the two diffraction gratings to specific angles. This paper describes on the grating assemblies, designed to rotate and stabilize the gratings. First the assembly itself and its special environment inside FIFI-LS is explained. Then a method is layed out how to monitor the performance of the drive and how to detect upcoming failures before they happen. The last chapter is dedicated to first inflight measurements of the position stability of the grating.
KEYWORDS: Telescopes, Sensors, Human-machine interfaces, Astronomy, Computing systems, Observatories, Signal to noise ratio, Electronics, Signal processing, Signal detection
We describe observational operations and data reduction for the science instrument FIFI-LS (Field Imaging Far Infrared
Line Spectrometer) onboard SOFIA (Stratospheric Observatory for Infrared Astronomy). First, the observation strategy
is explained, which plans all the various observing modes and parameters based on the targets and the limitations of the
observatory and instrument. Next, the observations must be created in a format readable by instrument control software,
via a system of algorithms. Once the observations have been planned and prepared, they must be scheduled, executed
and analysed, and this process is outlined. The data reduction system which processes the results from these
observations, beginning from retrieving raw data, to obtaining a FITS file data cube readable by analysis programs, is
described in detail.
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory, carrying a 2.5 m telescope onboard a heavily modified Boeing 747SP aircraft. SOFIA is optimized for operation at infrared wavelengths, much of which is obscured for ground-based observatories by atmospheric water vapor. The SOFIA science instrument complement consists of seven instruments: FORCAST (Faint Object InfraRed CAmera for the SOFIA Telescope), GREAT (German Receiver for Astronomy at Terahertz Frequencies), HIPO (High-speed Imaging Photometer for Occultations), FLITECAM (First Light Infrared Test Experiment CAMera), FIFI-LS (Far-Infrared Field-Imaging Line Spectrometer), EXES (Echelon-Cross-Echelle Spectrograph), and HAWC (High-resolution Airborne Wideband Camera). FORCAST is a 5–40 μm imager with grism spectroscopy, developed at Cornell University. GREAT is a heterodyne spectrometer providing high-resolution spectroscopy in several bands from 60–240 μm, developed at the Max Planck Institute for Radio Astronomy. HIPO is a 0.3–1.1 μm imager, developed at Lowell Observatory. FLITECAM is a 1–5 μm wide-field imager with grism spectroscopy, developed at UCLA. FIFI-LS is a 42–210 μm integral field imaging grating spectrometer, developed at the University of Stuttgart. EXES is a 5–28 μm high-resolution spectrograph, developed at UC Davis and NASA ARC. HAWC is a 50–240 μm imager, developed at the University of Chicago, and undergoing an upgrade at JPL to add polarimetry capability and substantially larger GSFC detectors. We describe the capabilities, performance, and status of each instrument, highlighting science results obtained using FORCAST, GREAT, and HIPO during SOFIA Early Science observations conducted in 2011.
The Stratospheric Observatory for Infrared Astronomy (SOFIA) has recently concluded a set of engineering flights for Observatory performance evaluation. These in-flight opportunities have been viewed as a first comprehensive assessment of the Observatory's performance and will be used to address the development activity that
is planned for 2012, as well as to identify additional Observatory upgrades. A series of 8 SOFIA Characterization
And Integration
flights have been conducted from June to December 2011. The HIPO science instrument in
conjunction with the DSI Super Fast Diagnostic Camera (SFDC) have been used to evaluate pointing stability,
including the image motion due to rigid-body and
flexible-body telescope modes as well as possible aero-optical
image motion. We report on recent improvements in pointing stability by using an Active Mass Damper system
installed on Telescope Assembly. Measurements and characterization of the shear layer and cavity seeing, as
well as image quality evaluation as a function of wavelength have been performed using the HIPO+FLITECAM
Science Instrument conguration (FLIPO). A number of additional tests and measurements have targeted basic
Observatory capabilities and requirements including, but not limited to, pointing accuracy, chopper evaluation
and imager sensitivity. This paper reports on the data collected during these
flights and presents current SOFIA
Observatory performance and characterization.
This paper describes the current status of FLITECAM, the near-infrared (1 - 5 μm) camera and spectrometer for
NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA). Due to a change in schedule FLITECAM’s
delivery was advanced, allowing it to be co-mounted with the HIPO instrument and used on four flights in October 2011
for observatory verification. Although not part of FLITECAM’s commissioning time, some preliminary performance
characteristics were determined. Image size as a function of wavelength was measured prior to the installation of active
mass dampers on the telescope. Preliminary grism spectroscopy was also obtained. In addition, FLITECAM was used to
measure the emissivity of the telescope and warm optics in the co-mounted configuration. New narrow band filters were
added to the instrument, including a Paschen alpha filter for line emission. Results are illustrated.
FIFI-LS (Field-Imaging Far-Infrared Line Spectrometer) is an imaging spectrograph for SOFIA comprised of two
medium resolution (R~2200) grating spectrometers feeding two 16x25 pixel detector arrays, which enable simultaneous
line observations across two wavelength ranges (42-110 μm and 110-210μm) each across a field of view of 5x5 pixel.
FIFI-LS will be the extragalactic spectroscopic workhorse for SOFIA. FIFI-LS has enough sensitivity to observe a
substantial sample of nearby galaxies. It also has the right combination of wavelength range and spatial resolution to
carry out unique new observations beyond those possible with Herschel, Spitzer, ISO and IRAS. As the effective
sensitivity of FIFI-LS is only about a factor of 3-5 lower than the PACS spectrometer onboard Herschel, mainly due to
an enhanced multiplexing advantage, FIFI-LS will build upon recent exciting scientific results and spearhead the post-
Herschel far-infrared era.
FIFI-LS is scheduled for commissioning onboard SOFIA in early 2014. An account on the instrument and its current
stratus will be presented.
HAWC (High-resolution Airborne Wideband Camera) is a facility science instrument for SOFIA (Stratospheric Observatory for Infrared Astronomy). It is a far-infrared camera designed for diffraction-limited imaging in four spectral passbands centered at wavelengths of 53, 89, 155, and 216 μm. Its detector is a 12x32 array of bolometers cooled to 0.2 K by an adiabatic demagnetization refrigerator. In this paper, we report on the development and testing of the instrument and its subsystems.
We present an overview of the science instrument program for the Stratospheric Observatory for Infrared Astronomy (SOFIA). Funded for an initial suite of facility and PI instruments, the SOFIA instrument development program includes imagers and spectrometers from both U.S. and German development teams. With an emphasis on lessons learned, we review the development of the facility instrument suite. We conclude with the anticipated role for SOFIA as a new technology test bed for the latest far-infrared detectors.
In the event of a cryostat vacuum failure, the subsequent liquid helium boil off can produce a significant pressure rise in the helium reservoir potentially causing damage to the cryostat. To preclude cryostat damage during such a failure, an analysis has been developed to predict the maximum internal pressure for the corresponding vent neck size and helium reservoir surface area at failure condition. To demonstrate that the analysis predicts correct pressure values, a series of experiments have been carried out at NASA Ames Research Center to measure the pressure profile during an induced failure. The maximum measured helium reservoir pressure is then used in the analysis to derive the heat load. The experiments have been conducted using a cylindrical helium and nitrogen cryostat with a variable size constriction insert in the helium neck to enable measuring the pressure rise across a range of effective neck areas. The experimentally derived heat flux on the uninsulated helium reservoir during an induced vacuum failure is 3.1 ± 0.2 W/cm2. Some preliminary test results are presented describing the effects of superinsulation, but this aspect of cryostat design is not extensively explored, as the design and materials selected may have highly variable results.
The airworthiness of science instruments that will fly onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) has been a critical area of concern during the first two years of the observatory development program. The SOFIA platform is a 747SP aircraft which will be operated under Federal Aviation Regulations (FAR Part 25) with a level of review and documentation regarding safety that is new to the astronomical community.
The South Pole Imaging Fabry-Perot Interferometer (SPIFI) is a direct detection, imaging, submillimeter spectrometer. The spectral resolving elements are a pair of cryogenic, scanning Fabry-Perot interferometers which use a free- standard Ni mesh for the etalon mirrors. The detectors for SPIFI are a 5 X 5 array of bolometers coupled to the focal plane with Winston cones. An adiabatic demagnetization refrigerator cools the bolometers to approximately 60 mK while a 3He system operates simultaneously as a thermal guard. SPIFI is intended to operate on the ASO/RO submillimeter telescope at the South Pole and on the JCMT telescope on Mauna Kea and will be used to study the gas- phase reservoirs of carbon in star-forming regions in our own and near-by galaxies. SPIFI takes advantage of three things: (1) Advanced bolometers that achieve background limited performance at very high resolving powers. (2) The imaging capability and high spectral resolving power of Fabry-Perot interferometers. (3) The superb atmospheric transmission in submillimeter bands possible from the South Pole. The SPIFI uses state-of-the-art monolithic silicon bolometers fabricated at the NASA Goddard Space Flight Center. The cryogenic, scanning Fabry-Perots in SPIFI were designed and built at Cornell and are an evolution of the design used with great success for the Kuiper Wide Field Camera. The 1.7 m Antarctic Submillimeter Telescope/Remote Observatory exploits what is thought to be the best submillimeter observing site in the world.
The joint US and German SOFIA project to develop and operate a 2.5 meter IR airborne telescope in a Boeing 747-SP is now in its second year. The Universities Space Research Association , teamed with Raytheon E-Systems and United Airlines, is developing and will operate SOFIA. The 2.5 meter telescope will be designed and built by a consortium of German companies led by MAN. Work on the aircraft and the preliminary mirror has started. First science flights will begin in 2001 with 20 percent of the observing time assigned to German investigators. The observatory is expected to operate for over 20 years. The sensitivity, characteristics, US science instrument complement, and operations concept for the SOFIA observatory, with an emphasis on the science community's participation are discussed.
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