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Proceedings Paper

Research on the influence of secondary mirror shadow coefficient upon Pan-Cassegrain system
Author(s): Chao-Ming Li; Jun-Hua Pan
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Paper Abstract

Pan-Cassegrain (PC) system is a new structure, which originates from the classical Cassegrain system. The most important character of the PC system is that a 4th order aspherical surface, which can be manufactured by using the spherical fabrication technology, is added in front of the primary spherical mirror. The principle of the PC system imaging principle is explained in this paper. And, the correcting lens design of PC system, whose aperture is 300mm and F/# is 10, is studied on conditions as follows: the secondary spherical mirror shadow coefficients are 1/2, 1/3, 1/4 and 1/5, respectively; field angle 2ω=1°. The relations among shadow coefficient, tube length and primary F/# are also analyzed. The results of calculation indicate that, with the reduction of shadow coefficient, the length of system tube will be short, system's aberrations will increase fast, and more correcting lens will be needed. It has a similar character of Cassegrain system and R-C system at this aspect. In practice, choosing an appropriate shadow coefficient is very important in manufacture according to the actual circumstance.

Paper Details

Date Published: 1 February 2006
PDF: 6 pages
Proc. SPIE 6034, ICO20: Optical Design and Fabrication, 603403 (1 February 2006); doi: 10.1117/12.668086
Show Author Affiliations
Chao-Ming Li, Soochow Univ. (China)
Jun-Hua Pan, Soochow Univ. (China)

Published in SPIE Proceedings Vol. 6034:
ICO20: Optical Design and Fabrication
James Breckinridge; Yongtian Wang, Editor(s)

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