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Proceedings Paper

Telescope in a bottle: a novel approach to upgrading a 32-in.-aperture classical Cassegrainian telescope for range instrumentation with IR sensors
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Paper Abstract

The title for this paper derives from the method selected for upgrading an older telescope which needed to meet current range instrumentation requirements in the infrared portion of the optical spectrum. A major constraint imposed on the project at its outset was the need to keep the older telescope tube, tracking mount and mobile platform at its home base in Florida. In contrast to the traditional way of building telescopes by first designing the optical system and then designing the housing and mount, this upgrade began with fitting a new structure within the confines of the existing housing while increasing the usable aperture from a 29.5 inch diameter Classical Cassegrainian design to a 32 inch aperture system. This new structure evolved from an improved design approach including the use of low thermal coefficient of expansion materials, special baffles and modern alignment techniques. The tube which was to serve as the bottle, was stripped of its optical components while a completely new internal structure was fabricated independently at a facility in California. The redesign and fabrication process began with a search for the original optical design data and a shopping list of parts to be either modified or redesigned to fit the existing light path through a donut ring which incorporates the telescope's trunnion axis, to a second folding mirror thus enabling an infrared camera to be focused along an overhead track parallel to the telescope's optical axis. All of the original optics were reassembled and potted into new mounts. The secondary mirror was placed into a large ball-knuckle assembly which insured rapid and precise alignment. During the process of building the independent structure, an installation kit or erector set was created. This erector set included special tooling for attaching a large headring, all four metering rods, baffles and adapters as well as the primary mirror retaining ring, inside the original tube. All hardware was shipped to the field site in Florida where final assembly took place using only heavy lifting equipment and a minimum of inexpensive alignment devices.

Paper Details

Date Published: 9 September 2002
PDF: 10 pages
Proc. SPIE 4771, Optomechanical Design and Engineering 2002, (9 September 2002); doi: 10.1117/12.482155
Show Author Affiliations
Joseph B. Houston Jr., Optical Engineering Consultant (United States)

Published in SPIE Proceedings Vol. 4771:
Optomechanical Design and Engineering 2002
Alson E. Hatheway, Editor(s)

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