30 September 2004 Integration, testing, and performance of the Infrared Multi-Object Spectrometer
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The Infrared Multi-Object Spectrometer (IRMOS) is a principle investigator-class instrument for the Kitt Peak National Observatory 2.1 m and Mayall 3.8 m telescopes. IRMOS is a near-IR (0.8-2.5 micron) spectrometer with low- to mid-resolving power (R = λ/Δλ = 300-3000). On the 3.8 m telescope, IRMOS produces simultaneous spectra of ~100 objects in its 2.8 x 2.0 arcmin field of view using a commercial micro electro-mechanical systems (MEMS) digital micro-mirror device (DMD) from Texas Instruments. The multi-mirror array DMD operates as a real-time programmable slit mask. The all-reflective optical design consists of two imaging subsystems. The focal reducer images the focal plane of the telescope onto the DMD field stop, and the spectrograph images the DMD onto a large-format detector. The instrument operates at ~90 K, cooled by a single electro-mechanical cryocooler. The bench and all components are made from aluminum 6061. There are three cryogenic mechanisms. We describe laboratory integration and test of IRMOS before shipment to Kitt Peak National Observatory. We give an overview of the optical alignment technique and integration of optical, mechanical, electrical and cryogenic subsystems. We compare optical test results to model predictions of point spread function size. We discuss some lessons learned and conclude with a prediction for performance on the telescope.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Raymond G. Ohl, Joseph A. Connelly, Robert F. Boyle, Rebecca J. Derro, Danette L. Fitzgerald, Matthew A. Greenhouse, Timothy J. Madison, John Eric Mentzell, Brian Nord, Leroy M. Sparr, Jason E. Hylan, Knute Ray, and John W. MacKenty "Integration, testing, and performance of the Infrared Multi-Object Spectrometer", Proc. SPIE 5492, Ground-based Instrumentation for Astronomy, (30 September 2004); doi: 10.1117/12.551494; https://doi.org/10.1117/12.551494

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