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Proceedings Paper

Telescope Design In The German Infrared Laboratory (GIRL)
Author(s): Rudolf Schlegelmilch
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Paper Abstract

The mirrors of the 40 cm GIRL telescope cooled by superfluid helium will consist of glass ceramic Zerodur. The poor thermal conductivity of this material called for unusual cooling procedures, the details of which have been investigated in laboratory tests. The assembly of the mirrors at the aluminium base occurs via an intermediate invar structure which is suited to maintain the optical quality after cooling. Special expansion compensators guarantee equal focussing conditions at laboratory and cryogenic temperatures. Vibration tests of the engineering model have proved the dimensional stability of critical components. The infrared reflectivity of different mirror desposits were measured under cold conditions.

Paper Details

Date Published: 22 September 1983
PDF: 5 pages
Proc. SPIE 0414, Optical Engineering for Cold Environments, (22 September 1983); doi: 10.1117/12.935890
Show Author Affiliations
Rudolf Schlegelmilch, Carl Zeiss (Federal Republic of Germany)

Published in SPIE Proceedings Vol. 0414:
Optical Engineering for Cold Environments
George W. Aitken, Editor(s)

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