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German REceiver for Astronomy at Terahertz Frequencies (GREAT)
GREAT is a dual channel heterodyne instrument that will provide high resolution spectra (up to R=108) in several frequency windows in the 0.490–4.747 THz range. The front-end unit consists of two independent dewars, each containing a set of mixers. Offered for Cycle 8 are is the seven-beam array upGREAT in its Low Frequency Array configuration for the [CII] line at 158 μm and High Frequency Array configuration for the [OI] line. Also available for Cycle 8 are all four 4GREAT bands at the following frequency ranges: 490–635 GHz (Herschel/HIFI band 1), 890–1100 GHz (Herschel/HIFI band 4), 1200–1500 GHz (GREAT L1 channel), and 2490–2590 GHz (GREAT M channel). The backend for each mixer is a Fast Fourier Transform spectrometer (XFFTS). Each XFFTS has 2 GHz bandwidth and 64,000 channels providing a resolution of 44 kHz. The beam size of GREAT is diffraction limited (14.1” at 158 μm).
Examples of GREAT scientific observations and summary of specifications: GREAT Flyer
Information applicable to the observing cycles can be found in their respective versions of the Observer's Handbook. Be sure that you are referencing the correct version of the handbook!
Use when citing SOFIA/GREAT results.
"GREAT: The SOFIA High-frequency Heterodyne Instrument"
Heyminck, S., et al., 2012, A&A, 542, L1.
"GREAT: A First light instrument for SOFIA"
Heyminck et al., 2008, ProcSPIE, 7014, 701410.
Graf et al., "GREAT: the German first light heterodyne instrument for SOFIA," Infrared Spaceborne Remote Sensing and Instrumentation XV, Marija Strojnik-Scholl, Editor, Proc. SPIE 6678, 66780K (2007), DOI: 10.1117/12.768027
Wagner-Gentner et al., "GREAT optics," Millimeter and Submillimeter Detectors for Astronomy II, Jonas Zmuidzinas, Wayne S. Holland, & Stafford Withington, Editors, Proc. SPIE 5498, 464 (2004), DOI: 10.1117/12.551236
Güsten, et al., "GREAT: the first-generation German heterodyne receiver for SOFIA," Airborne Telescope Systems, Ramsey K. Melugin & Hans-Peter Roeser, Editors, Proc. SPIE 4014, 23 (2000), DOI: 10.1117/12.389122 [pdf]