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Proceedings Paper • Open Access

Optical testing of lightweight large all-C/SiC optics

Paper Abstract

We carried out various tests of 800-mm-diameter aperture, lightweight optics that consisted wholly of carbon fiber-reinforced SiC composite, called HB-Cesic. A cryogenic optical test was performed on the primary mirror to examine any CTE irregularity as a surface change, and only small deformations were observed. The primary mirror was assembled with a convex secondary mirror into an optical system and tested under vacuum at the 6-m-diameter radiometer space chamber at Tsukuba Space Center of JAXA, where we have prepared interferometric metrological facilities to establish techniques to test large optical systems in a horizontal light-axis configuration. The wavefront difference between under vacuum and under atmosphere was confirmed to be less than 0.1 λ at λ=633 nm, if we realigned the optical axis of the interferometer and flat mirror under vacuum. We also demonstrated a stitching interferometry using the Φ800-mm optics by rotating a mask wheel of subapertures in front of the optical reference flat. The wavefront stitched from eight individual measurements of Φ275-mm subapertures differs from the full-aperture measurement without the mask by about 0.1 λ nm RMS, which showed the technique could able to be applied to test large telescopes especially for infrared wavelength region.

Paper Details

Date Published: 20 November 2017
PDF: 7 pages
Proc. SPIE 10565, International Conference on Space Optics — ICSO 2010, 105652E (20 November 2017); doi: 10.1117/12.2309218
Show Author Affiliations
M. Suganuma, Japan Aerospace Exploration Agency (Japan)
T. Imai, Japan Aerospace Exploration Agency (Japan)
H. Katayama, Japan Aerospace Exploration Agency (Japan)
M. Naitoh, Japan Aerospace Exploration Agency (Japan)
Y. Tange, Japan Aerospace Exploration Agency (Japan)
Y. Y. Yui, Japan Aerospace Exploration Agency (Japan)
K. Maruyama, Japan Aerospace Exploration Agency (Japan)
H. Kaneda, Nagoya Univ. (Japan)
T. Nakagawa, Japan Aerospace Exploration Agency (Japan)
M. Kotani, Japan Aerospace Exploration Agency (Japan)

Published in SPIE Proceedings Vol. 10565:
International Conference on Space Optics — ICSO 2010
Errico Armandillo; Bruno Cugny; Nikos Karafolas, Editor(s)

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