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21 August 1998 EXES: an echelon cross echelle spectrograph for SOFIA
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To study narrow features in quiescent molecular clouds, a high spectral resolution, high sensitivity instrument is required. We present the design and capabilities of a mid-IR spectrograph being built as a PI instrument for the Stratospheric Observatory for IR Astronomy. The Echelon- Cross-Echelle Spectrograph (EXES) will operate from 5.5-28.5 micrometers in three spectroscopic modes: R approximately 105, 104, and 1500. EXES is similar in concept to our ground based instrument, TEXES. EXES consists of three chambers. The first chamber contains focal-reducing optics. The second chamber houses the high resolution grating, an echelon. Discussion of the echelon can be found elsewhere in this volume. The third chamber contains an echelle grating and a first order grating mounted back-to-back. A flip mirror selects operating mode by either directing light into the echelon chamber or allowing the light to pass through to the grating chamber. Re-imaging optics upstream of the detector provide two plate scales. The detector, a 256 by 256 pixel Si:As IBC, is in a baffled subsection of the third chamber. Finally, the low resolution grating serves as a slit positioning camera when it is rotated face on.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Matthew J. Richter, John H. Lacy, Daniel T. Jaffe, Mary Kay Hemenway, and Wanglong Yu "EXES: an echelon cross echelle spectrograph for SOFIA", Proc. SPIE 3354, Infrared Astronomical Instrumentation, (21 August 1998);

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