A high stray light cryogenic telescope has been developed to provide spatial definition for a Fourier transform spectrometer. The system is all-aluminum and uses off-axis superpolished parabolas with an advanced baffle system for high stray light performance at cryogenic temperatures. The all-reflective optical system is capable of better than 0.1 mrad resolution over a half a degree field of view. The brazed mechanical structure is integrated with a careful thermal design, allowing the optics to maintain liquid helium region temperatures without the use of thermal straps. The telescope has been tested for stray light, optical performance at cryogenic temperatures and against shuttle environmental requirements. A discussion of the design analyses, test techniques, and measured results will be included in the paper.
J. S. Titus,
Donald R. Smith,
"Cryogenic Infrared Radiance Instrument For Shuttle (CIRRIS) Telescope," Optical Engineering 23(3), (1 June 1984). https://doi.org/10.1117/12.7973286