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Proceedings Paper

Design Aspects Of The University Of Texas 7.6M Telescope - Part I
Author(s): Frank B. Ray
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Paper Abstract

The University of Texas 7.6m telescope design has evolved through several stages, each bringing added strength. and efficiency to a well-planned overall approach. The current design is based on an f/1.8 primary focal ratio with an f/13.5 Nasmyth beam directed through the elevation bearings. Recent studies include consideration of a class of correctors defined for an fill.° internal (Epps) focus by Charles F. W. Harmer, optical consultant. A standard Surrurier truss arrangement for the optical support structure assures equal gravity flexure. The Nasmyth flat and corrector housing are supported by a rigid elevation box structure. In the area of primary mirror design and support, research toward a superlative design is still in progress, primarily to take advantage of the rapidly emerging techniques of high efficiency borosilicate spin casting developed at the University of Arizona. There are some significant tradeoffs in terms of rib structure, span of unribbed sections, total weight, casting difficulty, and design of a tunable mirror support. A ribbed borosilicate mirror of the 7.6m class is very nearly passively supportable, provided the image specifications are not too stringent, and its figure stability can be made considerably better than any mirror extant with a modest amount of force variation in the axial support mechanism. Mirror support consists of a combination of pneumatic and counterweighted flotation systems with a low bandwidth tuning system added for figure improvement. Large classes of external loads, to be expected in a realistic observatory environment, may be obviated by such a system.

Paper Details

Date Published: 22 October 1985
PDF: 5 pages
Proc. SPIE 0542, Optical Fabrication & Testing Workshop, (22 October 1985); doi: 10.1117/12.948159
Show Author Affiliations
Frank B. Ray, University of Texas McDonald Observatory (United States)

Published in SPIE Proceedings Vol. 0542:
Optical Fabrication & Testing Workshop
Robin S. McDowell, Editor(s)

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