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Proceedings Paper

Design of a prototype primary mirror segment positioning actuator for the Thirty Meter Telescope
Author(s): Kenneth R. Lorell; Jean-Noël Aubrun; Robert R. Clappier; Scott W. Miller; Mark Sirota
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Paper Abstract

The Thirty Meter Telescope (TMT) is a collaborative project between the California Institute of Technology (CIT), the University of California (UC), the Association of Universities for Research in Astronomy (AURA), and the Association of Canadian Universities for Research in Astronomy (ACURA). In order for the Thirty Meter Telescope (TMT) to achieve the required optical performance, each of its 738 primary mirror segments must be positioned relative to adjacent segments with nanometer-level accuracy. Three in plane degrees of freedom are controlled via a passive Segment Support Assembly which is described in another paper presented at this conference (paper 6273-45). The remaining three out of plane degrees of freedom, tip, tilt, and piston, are controlled via three actuators for each segment. Because of its size and the shear number of actuators, TMT will require an actuator design, departing from that used on the Keck telescopes, its successful predecessor. Sensitivity to wind loads and structural vibrations, the large dynamic range, low operating power, and extremely reliable operation, all achieved at an affordable unit cost, are the most demanding design requirements. This paper describes a concept that successfully meets the TMT requirements, along with analysis and performance predictions. The actuator concept is based on a prototype actuator developed for the California Extremely Large Telescope (CELT) project. It relies on techniques that achieve the required accuracy while providing a substantial amount of vibration attenuation and damping. A development plan consisting of a series of prototype actuators is envisioned to verify cost, reliability, and performance before mass production is initiated. The first prototype (P1) of this development plan is now being built and should complete initial testing by the end of 2nd QTR 06.

Paper Details

Date Published: 23 June 2006
PDF: 11 pages
Proc. SPIE 6267, Ground-based and Airborne Telescopes, 62672T (23 June 2006); doi: 10.1117/12.672917
Show Author Affiliations
Kenneth R. Lorell, Marjan Research (United States)
Jean-Noël Aubrun, Marjan Research (United States)
Robert R. Clappier, Marjan Research (United States)
Scott W. Miller, Marjan Research (United States)
Mark Sirota, Thirty Meter Telescope Project (United States)

Published in SPIE Proceedings Vol. 6267:
Ground-based and Airborne Telescopes
Larry M. Stepp, Editor(s)

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