SOFIA eNewsletter for Scientists
SOFIA First-Light Instruments Highlights

     vol. 3    January 4, 2002
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SOFIA, the Stratospheric Observatory For Infrared Astronomy, will be a 2.5 meter telescope operating in a 747SP aircraft.

One of the strongest attributes of SOFIA is its large complement of state-of-the-art first generation instruments. In this newsletter we give you a brief description of the present complement of instruments and a status of their development. For more information on SOFIA's first generation of instruments, please visit our website at: Further information will be sent out when USRA announces the call for second generation instrument proposals.

HAWC (PI Al Harper, Univ. of Chicago):
The High-resolution Airborne Wideband Camera is a far- infrared camera designed to cover the 40-300 micron spectral range at the highest possible angular resolution. The optics consists of four interchangeable sets of re-imaging lenses that enable optimized, diffraction-limited imaging. This Facility class instrument contains a 12x32 pixel array of bolometer detectors. The array will be cooled by an adiabatic demagnetization refrigerator and operated at a temperature of 0.2 K. With its spectral range and angular resolution, HAWC will be used to study source energetics and morphology as well as the physics and chemistry of interstellar clouds. Presently, the prototype bolometer arrays are being tested and will be used this summer at the CSO in Hawaii. The HAWC instrument should be ready shortly after first light.
HAWC Homepage:

The First Light Infrared Test Experiment CAMera, is a Facility class multi-purpose near-infrared camera designed to test the image quality and thermal background of the SOFIA telescope. The camera works in the 1 - 5.5 micron range. The instrument includes a 1024 x 1024 InSb detector array, which produces an 8 arcmin field of view. Grisms will allow low resolution spectroscopy with typical resolving powers of R=2000. In addition to its role as a test camera, FLITECAM will also produce images for public outreach and will be used for surveys of star-formation regions and spectroscopic studies. It can also be used concurrently with HIPO for planetary occultations. The FLITECAM dewar has passed its airworthiness reviews and is presently being machined. The 1024x1024 science grade array and electronics are being tested in the UCLA lab. FLITECAM will be ready for observatory testing in 2003.
FLITECAM Homepage:

FORCAST (PI Terry Herter, Univ. of Cornell):
The Faint Object infraRed CAmera for the Sofia Telescope is a Facility class mid-infrared camera capable of imaging in the 5-8, 17-25 and/or 25-40 micron range. Using the latest 256x256 Si:As and Si:Sb blocked-impurity-band detector array technology to provide high-sensitivity wide-field imaging, this instrument will sample at 0.75 arcsec/pixel giving a 3.2 arcmin x 3.2 arcmin instantaneous field-of-view. FORCAST will provide the highest spatial resolution possible from SOFIA and will primarily be used for studying protostellar environments, young star clusters, molecular clouds and galaxies. The science grade Si:As detector is being tested in the Cornell laboratory. The Si:Sb science detector will be delivered this spring. FORCAST will be available at or near first- light in 2004.
FORCAST Homepage:

EXES (PI John Lacy, Univ. of Texas):
The Echelon Cross Echelle Spectrograph is a 5-28.5 micron high resolution spectrograph. This PI instrument will have a maximum resolution of 3km/s. It will also have lower resolution modes of 30 km/s and 100km/s. The low-background 256x256 Si:As detector was developed for use on SIRTF. The echelon grating has been manufactured, and the detector array has been operated in another ground-based spectrometer. EXES is expected to be ready for use on SOFIA at first light, but its efficiency may be affected by the first light image stability.
EXES Homepage:

SAFIRE (PI Harvey Moseley, NASA-GSFC):
The Submillimeter And Far-InfraRed Experiment is a versatile imaging Fabry-Perot spectrograph working in the range of 100 to 655 microns. This PI instrument uses a state-of-the-art transition edge bolometer array and operates at a spectral resolution of 150 km/s. A small prototype array of bolometers has been tested in Hawaii. The instrument should be available on SOFIA several years after first light.
SAFIRE Homepage:

GREAT (PI Rolf Guesten, MPIfR):
The German REceiver for Astronomy at THz frequencies is a dual channel heterodyne PI instrument with high spectral resolution in the 63 to 188 micron (1.6 to 4.7 THz) region. The spectral resolution is < 0.3 km/s. The instrument will be able to make unique studies of a number of astrophysically important lines such as [CII] at 158 microns, [OI] at 63 microns, and HD at 112 microns. The instrument should be ready near first light in late 2004.

CASIMIR (PI Jonas Zmuidzinas, Caltech):
The Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver is a submillimeter and far-infrared heterodyne spectrometer. This PI class instrument works in the wavelength range from 150 to 600 microns (500-2000 GHz) and will have extremely high spectral resolution of > 0.3 km/sec. The SIS mixers using NbTiN superconductors have been tested in the Cal-Tech lab. Their sensitivity on SOFIA, for most lines, will be 200 times higher than the spacecraft SWAS, or the SOFIA predecessor, KAO. CASIMIR is expected to be available as a PI instrument just after SOFIA's first light in late 2004.
CASIMIR Homepage:

FIFI-LS (PI Albrecht Poglitsch, MPE Garching):
The Far-Infrared Field Imaging Line Spectrometer is a German PI class integral field unit spectrometer. The spectral resolution is 150-300 km/sec. It operates in the 42 to 210 micron region with two wavelength channels and two separate array detectors. The field of view of the short wavelength channel (42-110 microns) is 30"x30" with 6" pixels and the long wavelength channel (110-210 microns) is 60"x 60" with 12" pixels. The principle science driver is studies of the interstellar medium in our galaxy and other galaxies, especially ultra-luminous infrared galaxies. The long wavelength stressed Ga:Ge detector array is presently being tested. The grating mechanism has been prototyped. FIFI-LS with only its long-wavelength channel will be ready to fly on SOFIA at first light.
FIFI-LS Homepage:

HIPO (PI Ted Dunham, Lowell Observatory):
The High-speed Imaging Photometer for Occultations is a special-purpose science instrument that will provide simultaneous high-speed time resolved imaging photometry at two optical wavelength channels 0.3-0.6 microns and 0.4-1.1 microns. The instrument's detectors are silicon CCDs with a 1Kx1K format and 1 arsecond pixels providing a 5.6 arcminute square field of view. HIPO will be able to be co-mounted with the FLITECAM instrument and will also be used for critical tests of the completed SOFIA Observatory. HIPO's main scientific objective is observation of stellar occultations of planetary objects. HIPO will be ready for observatory testing in 2003.


A Facility-class Instrument (FI) is a general purpose, reliable and robust instrument that provides state-of-the-art science performance at commissioning, through the use of modern, but mature technologies. It is expected that this class of instruments will routinely be operated and maintained by a designated USRA FI scientist in support of General Investigators (GI's) who will not be required to have extensive knowledge or experience in infrared instrumentation or observing techniques. In the USRA peer review, three facility class instruments were selected for development.**

A Principal Investigator-class Instrument (PI) is a general purpose instrument that is developed and maintained at the state-of-the-art throughout its useful operating life, by the Principal Investigator. It can be used by the GI's in collaboration with the PI's.

** One of the Facility Class instruments, AIRES, has been cancelled due to cost overruns and a lack of additional funds.

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