The Infrared Astronomical Satellite (IRAS) was designed to operate at 2K, and over the spectral range of 8 to 120 micrometers. The focal plane is approximately 2 by 3 inches in size, and contains 62 individual field stop apertures, each with its own field lens, one or more filters and a detector. The design of the lenses involved a number of difficulties and challenges that are not usually encountered in optical design. Operating temperature is as-sumed during the design phase, which requires reliable information on dN/dT (Index Coeffi-cient) for the materials. The optics and all supporting structures are then expanded to room temperature, which requires expansion coefficient data on the various materials, and meticulous attention to detail. The small size and dense packaging, as well as the high precision required, further contributed to the magnitude of the task.

Date Published: 1 February 1985
PDF: 7 pages
Proc. SPIE 0509, Cryogenic Optical Systems and Instruments I, (1 February 1985); doi: 10.1117/12.944983

Published in SPIE Proceedings Vol. 0509:
Cryogenic Optical Systems and Instruments I
Ramsey K. Melugin, Editor(s)