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Proceedings Paper

The active primary mirror assembly for the SOAR telescope
Author(s): Conrad Neufeld; Marie Christine Zolcinski-Couet; Michael Keane; Gregory Ruthven
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Paper Abstract

The details of the design and the achieved performance of the recently completed primary mirror assembly for the SOAR telescope are described in this paper. The mirror is unique in that it uses a solid 4.3 meter diameter ULE lightweight meniscus primary mirror only 100 mm thick. The ULE substrate weighs approximately 3200 kg. The figure of the primary mirror surface is controlled with 120 electro-mechanical actuators that are force feedback controlled. Details of the design of the 4.1 meter clear aperture F=1.75 active primary mirror are presented. The figure control actuators are force controlled to correct aberrations induced by thermal and elevation changes affecting the telescope. A Calibration Wavefront Sensor provides input data to generate lookup tables used to develop the force commands at all zenith angles and temperatures. During the design development phase of the program the mirror was analyzed using NASTRAN finite element modeling. During optical metrology testing the ability to accurately induce shapes into the mirror surface including Zernike polynomials was compared to the NASTRAN predictions. Details of the results of this testing will be presented including the magnitude of force to impose specific Zernike polynomial shapes and the fidelity of the resulting shapes compared to the analysis.

Paper Details

Date Published: 28 September 2004
PDF: 11 pages
Proc. SPIE 5489, Ground-based Telescopes, (28 September 2004); doi: 10.1117/12.551375
Show Author Affiliations
Conrad Neufeld, Goodrich Corp. (United States)
Marie Christine Zolcinski-Couet, Goodrich Corp. (United States)
Michael Keane, Goodrich Corp. (United States)
Gregory Ruthven, Goodrich Corp. (United States)

Published in SPIE Proceedings Vol. 5489:
Ground-based Telescopes
Jacobus M. Oschmann, Editor(s)

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