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Proceedings Paper

Mechanical structure of JNLT: analysis of mirror deflection due to wind loading
Author(s): Noboru Itoh; Izumi Mikami; Takeshi Noguchi; Yasuhiro Shimizu; Yasumasa Yamashita; Jerry Sovka; Robert A. McLaren; D. Andre Erasmus
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Paper Abstract

The Japanese National Large Telescope (JNLT) will use a thin meniscus mirror of 7.5 m diameter and 0.2 m thickness as a primary mirror. One of the biggest concerns is mirror deflection due to dome-inside wind loading, which varies with time not only in its pressure amplitude but also in its pressure profile on the mirror surface. To analyze such mirror deflection, a method combining modal analysis and random vibration analysis was introduced. From the rms mirror deflection obtained by this method, the image quality degradation is considered to be better than that budgeted as wind loading degradation. Information about the method and typical result of the analysis are presented.

Paper Details

Date Published: 1 July 1990
PDF: 12 pages
Proc. SPIE 1236, Advanced Technology Optical Telescopes IV, (1 July 1990); doi: 10.1117/12.19257
Show Author Affiliations
Noboru Itoh, Mitsubishi Electric Corp. (Japan)
Izumi Mikami, Mitsubishi Electric Corp. (Japan)
Takeshi Noguchi, National Astronomical Observatory (Japan)
Yasuhiro Shimizu, National Astronomical Observatory (Japan)
Yasumasa Yamashita, National Astronomical Observatory (Japan)
Jerry Sovka, Canada France Hawaii Telescope Corp. (United States)
Robert A. McLaren, Canada-France-Hawaii Telescope Corp. (United States)
D. Andre Erasmus, Univ. of Hawaii (South Africa)

Published in SPIE Proceedings Vol. 1236:
Advanced Technology Optical Telescopes IV
Lawrence D. Barr, Editor(s)

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