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Proceedings Paper

Gimbal mechanism for cryogenic alignment of 1-meter diameter optics
Author(s): Robert G. Chave; Alfred Edward Nash III; James Hardy
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Paper Abstract

A two axis optical gimbal mechanism for aligning 1 meter diameter telescope primaries and test flat mirrors at temperatures from 300 to 4.2 K was constructed for use in the SIRTF Telescope Test Facility (STTF). This mechanism consists of an aluminum frame, pivoting on a monoball bearing, and driven in tip and tilt by tungsten di-sulfide lubricated lead screws with external drive motors. Flexures decouple the optical support frame from stresses generated by differential rates of cooling. A second set of flexures decouples the mirror mechanically and thermally from distortion in the gimbal mechanism. The mechanism provides sub arc-second resolution in either axis, while limiting the heat leak to less than 100 mW at 4.2 K. Linear variable differential tranformers are used at temperatures from 300 to 4.2 K to measure a home position. The STTF and gimbal are presently operational, and have been used in two separate interferometric measurements of a 0.5 meter, f 4.0 beryllium spherical mirror at 6 K. The gimbal will be used in the interferometric testing of a beryllium telescope primary mirror from the Infrared Technology Testbed, for the Space Infrared Telescope Facility at JPL.

Paper Details

Date Published: 6 September 1995
PDF: 11 pages
Proc. SPIE 2542, Optomechanical and Precision Instrument Design, (6 September 1995); doi: 10.1117/12.218669
Show Author Affiliations
Robert G. Chave, Jet Propulsion Lab. (United States)
Alfred Edward Nash III, Jet Propulsion Lab. (United States)
James Hardy, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 2542:
Optomechanical and Precision Instrument Design
Alson E. Hatheway, Editor(s)

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