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Proceedings Paper

Advancement of the segment support system for the Thirty Meter Telescope primary mirror
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Paper Abstract

This paper presents refinements to the design of the TMT primary mirror segment passive-support system that are effective in reducing gravity print-through and thermal distortion effects. First, a novel analytical method is presented for tuning the axial and lateral support systems in a manner that results in improved optical performance when subject to varying gravity fields. The method utilizes counterweights attached to the whiffletrees to cancel astigmatic and comatic errors normally resulting when the lateral support system resists transverse loads induced by gravity. Secondly, several central diaphragm designs are presented and analyzed to assess lateral-gravity and thermal distortion performance: 1) a simple flat diaphragm, 2) a stress-relieving diaphragm having a slotted outer rim and a circumferential convolution near the outside diameter, and 3) a flat diaphragm having a slotted outer rim. The latter design is chosen based on results from analytical studies which show it to have better overall optical performance in the presence of gravity and thermal environments.

Paper Details

Date Published: 23 July 2008
PDF: 16 pages
Proc. SPIE 7018, Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, 701810 (23 July 2008); doi: 10.1117/12.790176
Show Author Affiliations
Eric C. Williams, TMT Observatory Corp. (United States)
Curtis Baffes, Jet Propulsion Lab. (United States)
Terry Mast, Univ. of California, Santa Cruz (United States)
Jerry Nelson, Univ. of California, Santa Cruz (United States)
Benjamin Platt, Jet Propulsion Lab. (United States)
R. J. Ponchione, HYTEC, Inc. (United States)
Eric Ponslet, HYTEC, Inc. (United States)
Shahriar Setoodeh, HYTEC, Inc. (United States)
Mark Sirota, TMT Observatory Corp. (United States)
Vince Stephens, HYTEC Inc. (United States)
Larry Stepp, TMT Observatory Corp. (United States)
Alan Tubb, HYTEC, Inc. (United States)

Published in SPIE Proceedings Vol. 7018:
Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)

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