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Proceedings Paper

Mounting large lenses in wide-field instruments for the converted MMT
Author(s): Robert G. Fata; Daniel G. Fabricant
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Paper Abstract

We describe the techniques that we have used to mount large optics in three wide-field instruments for the converted MMT: the wide-field corrector uses to provide a 1 degree diameter field at the f/5 focus of the converted MMT, the Hectospec bench spectrograph fed by 300 optical fibers and the wide- field dual-beam Binospec spectrograph. These optics are primarily refractive elements with diameters between 0.2 and 0.8 m that must be mounted from their edges, although we also describe mounts for two large mirrors in the Hectospec bench spectrograph. Both the wide-field corrector and Binospec mounts must perform under varying gravity loads: the corrector is fixed to the converted MMT's primary mirror cell and is tilted from zenith to horizon while Binospec is mounted at the converted MMT's Cassegrain focus. Furthermore, the optics mounts for both instruments must fit within tight space constraints. The Hectospec spectrograph is mounted in the MMT's rotating building and experiences a constant gravity vector. In all cases, the mounts must perform over a wide temperature range, -20 to 20 degrees Celsius, so the issue of differential thermal expansion between the mounts and optics must be carefully considered. As a result, the mounts we discuss include either RTV elastomeric or flexural elements.

Paper Details

Date Published: 9 July 1998
PDF: 10 pages
Proc. SPIE 3355, Optical Astronomical Instrumentation, (9 July 1998); doi: 10.1117/12.316812
Show Author Affiliations
Robert G. Fata, Harvard-Smithsonian Ctr. for Astrophysics (United States)
Daniel G. Fabricant, Harvard-Smithsonian Ctr. for Astrophysics (United States)


Published in SPIE Proceedings Vol. 3355:
Optical Astronomical Instrumentation
Sandro D'Odorico, Editor(s)

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