The Assembly and Measurement of Corrector Lens of a Cassegrain Telescope

Abstract:

Corrector lens assembly is used to expand the field of view of a Cassegrain Telescope. There are usually three to five lenses in it. For the assembly of such a kind of high precision optics, decenter and tilt of each optical component and air space between components are key issues to be qualified. In the present study, four lenses were designed. Individual control of centering of the component and air space were achieved by assembling the component into a precision machined subcell. The lens positions were defined by precision spacers according to the designed values. To compensate various thermal expansions of glass and metal, elastomer material was used. Considering the deviation of manufacturing from design data, manufactured data were put into optical software for re-optimization, and air spaces between lenses were obtained. This gives excellent accuracy at low cost. Base on present lens mounting design and lens manufacturing quality, centering error was eliminated by lateral adjustment, which leaded to a good alignment. In this paper, the method for aligning the optics with the barrel assembly is presented and centering error measured by a double autocollimator is listed. In addition, test results of thermal cycling and vibration tests on the corrector lens assembly are discussed.

• Periodical: Key Engineering Materials (Volume 625)
• Pages: 339-345
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.625.339
• Online since: August 2014
• Authors: Po Han Huang*, Ming Ying Hsu, Ting Ming Huang, Ren Jyue Guo, Jhih Yang Lin, Zong Yao Chen
• Keywords: Cassegrain Telescope, Corrector Lens, Decenter, Thermal Cycling, Tilt, Vibration

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