1 February 1985 Performance Optimization Of A Cryogenically Cooled Chopping Mirror
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Abstract
Substantial improvements in infrared sensor technology, the ability to design optics suitable for use at cryogenic temperatures, and the advent of Space Shuttle operations have spurred the development of the Space Infrared Telescope Facility (SIRTF). SIRTF, operating at cryogenic temperatures, will be nearly three orders of magnitude more sensitive than the current generation of infrared telescopes. The unique ability of a cooled infrared telescope operating above the earth's atmosphere to detect and measure extremely faint objects is further enhanced by a technique called spatial chopping. Spatial chopping requires the telescope secondary mirror to execute a rapid back-and-forth motion in a pattern closely approximating a square wave. This motion, performed at frequencies ranging from 1 to 40 Hz with amplitudes between two and 30 arcminutes, permits a continuous comparison of an object-field containing background radiation only with an adjacent field containing background radiation plus source radiation. By collecting data from both object fields and subtracting the resultant outputs, the signal-to-noise ratio of very weak sources is substantially improved.
© (1985) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. N. Aubrun, K. R. Lorell, "Performance Optimization Of A Cryogenically Cooled Chopping Mirror", Proc. SPIE 0509, Cryogenic Optical Systems and Instruments I, (1 February 1985); doi: 10.1117/12.944979; https://doi.org/10.1117/12.944979
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