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Proceedings Paper

Measurement of large optical surfaces for fabrication using a nonoptical technique
Author(s): Robert S. Breidenthal
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Paper Abstract

A ten meter astronomical telescope is being constructed using a phased array of two meter segments. This requires manufacture of a large number of off-axis segments and emphasizes the desirability of rapid manufacture and smoothness of finish of the segments. These two requirements have been met at Itek by combining surface figure measurement of a mirror using a multiple probe mechanical bar profilometer and fabrication of that mirror by stressed mirror polishing. Through the use of the multiple probe bar profilometer, a mirror segment can be measured to an accuracy of 0.047 microns rms surface error in a period of less than 90 minutes, including data processing time. This test has allowed us to manufacture 12 off-axis segments with a final surface error, after low-order correction by the in-use mount, of approximately .02 microns rms. The average rate for the entire grind and polish fabrication cycle is six weeks per mirror

Paper Details

Date Published: 26 March 1992
PDF: 7 pages
Proc. SPIE 1618, Large Optics II, (26 March 1992); doi: 10.1117/12.58047
Show Author Affiliations
Robert S. Breidenthal, Litton Itek Optical Systems (United States)

Published in SPIE Proceedings Vol. 1618:
Large Optics II
Robert E. Parks, Editor(s)

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