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Optical Engineering • Open Access

λAlignment and assembly process for primary mirror subsystem of a spaceborne telescope
Author(s): Wei-Cheng Lin; Shenq-Tsong Chang; Sheng-Hsiung Chang; Chen-Peng Chang; Yu-Chuan Lin; Chi-Chieh Chin; Hsu-Pin Pan; Ting-Ming Huang

Paper Abstract

In this study, a multispectral spaceborne Cassegrain telescope was developed. The telescope was equipped with a primary mirror with a 450-mm clear aperture composed of Zerodur and lightweighted at a ratio of approximately 50% to meet both thermal and mass requirements. Reducing the astigmatism was critical for this mirror. The astigmatism is caused by gravity effects, the bonding process, and deformation from mounting the main structure of the telescope (main plate). This article presents the primary mirror alignment, mechanical ground-supported equipment (MGSE), assembly process, and optical performance test used to assemble the primary mirror. A mechanical compensated shim is used as the interface between the bipod flexure and main plate. The shim was used to compensate for manufacturer errors found in components and differences between local coplanarity errors to prevent stress while the bipod flexure was screwed to the main plate. After primary mirror assembly, an optical performance test method called a bench test with an algorithm was used to analyze the astigmatism caused by the gravity effect and deformation from the mounting or supporter. The tolerance conditions for the primary mirror assembly require the astigmatism caused by gravity and mounting force deformation to be less than P−V0.02 λ at 632.8 nm. The results demonstrated that the designed MGSE used in the alignment and assembly processes met the critical requirements for the primary mirror assembly of the telescope.

Paper Details

Date Published: 18 November 2015
PDF: 11 pages
Opt. Eng. 54(11) 115109 doi: 10.1117/1.OE.54.11.115109
Published in: Optical Engineering Volume 54, Issue 11
Show Author Affiliations
Wei-Cheng Lin, Instrument Technology Research Ctr. (Taiwan)
Shenq-Tsong Chang, Instrument Technology Research Ctr. (Taiwan)
Sheng-Hsiung Chang, National Space Organization (Taiwan)
Chen-Peng Chang, National Space Organization (Taiwan)
Yu-Chuan Lin, Instrument Technology Research Ctr. (Taiwan)
Chi-Chieh Chin, National Space Organization (Taiwan)
Hsu-Pin Pan, Instrument Technology Research Ctr. (Taiwan)
Ting-Ming Huang, Instrument Technology Research Ctr. (Taiwan)

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