Wavefront measurement of space infrared telescopes at cryogenic temperature

Hidehiro Kaneda; Takashi Onaka; Takao Nakagawa; Keigo Enya; Hiroshi Murakami; Ryoji Yamashiro; Tatsuhiko Ezaki; Yasuyuki Numao; Yoshikazu Sugiyama

doi:10.1117/12.624798

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19 October 2005 Wavefront measurement of space infrared telescopes at cryogenic temperature

Hidehiro Kaneda, Takashi Onaka, Takao Nakagawa, Keigo Enya, Hiroshi Murakami, Ryoji Yamashiro, Tatsuhiko Ezaki, Yasuyuki Numao, Yoshikazu Sugiyama

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Proceedings Volume 5965, Optical Fabrication, Testing, and Metrology II; 59650X (2005) https://doi.org/10.1117/12.624798
Event: Optical Systems Design 2005, 2005, Jena, Germany

Abstract

In this paper, we describe our recent activities on wave-front measurement of space infrared telescopes. Optical performance of the 685-mm lightweight telescope on board the Japanese infrared astronomical satellite, ASTRO-F, has been evaluated at cryogenic temperatures. The mirrors of the ASTRO-F telescope are made of sandwich-type silicon carbide (SiC) material, comprising porous core and CVD coat of SiC on the surface. The total wavefront errors of the telescope were measured with an interferometer from outside a liquid-helium chamber; a 75-cm reflecting flat mirror was used for auto-collimating the light from the interferometer. The cryogenic deformation of the flat mirror was derived independently by shifting it in the chamber and its contribution to the wavefront error was removed. In addition to the ASTRO-F telescope, we are currently developing a 3.5-m telescope system for SPICA, the next Japanese infrared astronomical satellite project. Details of our methodology for the ASTRO-F telescope, together with our optical test plan for the SPICA telescope, are reported.

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Hidehiro Kaneda, Takashi Onaka, Takao Nakagawa, Keigo Enya, Hiroshi Murakami, Ryoji Yamashiro, Tatsuhiko Ezaki, Yasuyuki Numao, and Yoshikazu Sugiyama "Wavefront measurement of space infrared telescopes at cryogenic temperature", Proc. SPIE 5965, Optical Fabrication, Testing, and Metrology II, 59650X (19 October 2005); https://doi.org/10.1117/12.624798

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