NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Ambient and Cryogenic Alignment Verification and Performance of the Infrared Multi-Object SpectrometerThe Infrared Multi-Object Spectrometer (IRMOS) is a facility instrument for the Kitt Peak National Observatory 4 and 2.1 meter telescopes. IRMOS is a near-IR (0.8 - 2.5 micron) spectrometer with low- to mid-resolving power (R = 300 - 3000). IRMOS produces simultaneous spectra of approximately 100 objects in its 2.8 x 2.0 arc-min field of view using a commercial Micro Electro-Mechanical Systems (MEMS) Digital Micro-mirror Device (DMD) from Texas Instruments. The IRMOS 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 the detector. We describe ambient breadboard subsystem alignment and imaging performance of each stage independently, and the ambient and cryogenic imaging performance of the fully assembled instrument. Interferometric measurements of subsystem wavefront error serve to venfy alignment, and are accomplished using a commercial, modified Twyman-Green laser unequal path interferometer. Image testing provides further verification of the optomechanical alignment method and a measurement of near-angle scattered light due to mirror small-scale surface error. Image testing is performed at multiple field points. A mercury-argon pencil lamp provides spectral lines at 546.1 nm and 1550 nm, and a CCD camera and IR camera are used as detectors. We use commercial optical modeling software to predict the point-spread function and its effect on instrument slit transmission and resolution. Our breadboard test results validate this prediction. We conclude with an instrument performance prediction for first light.
Document ID
20030113055
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Connelly, Joseph A.
Ohl, Raymond G.
Mink, Ronald G.
Mentzell, J. Eric
Saha, Timo T.
Tveekrem, June L.
Hylan, Jason E.
Sparr, Leroy M.
Chambers, V. John
Hagopian, John G.
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Instrumentation And Photography
Meeting Information
Meeting: SPIE-Optical Science and Technology Annual Meeting
Location: San Diego, CA
Country: United States
Start Date: August 3, 2003
End Date: August 8, 2003
Sponsors: International Society for Optical Engineering
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available