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Proceedings Paper

Support of thin-meniscus primary for SOFIA
Author(s): Hans-Juergen Meier
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Paper Abstract

The thin meniscus for SOFIA has reduced weight at the cost of mirror stiffness. As this stiffness is reduced, the support system becomes more complicated in order to hold the mirror in the required optical shape regardless of the deformation of the supporting cell structure. The coupling between mirror cell and meniscus is equivalent to a kind of whiffle tree, which reduces its large number of axial support points down to exactly three points, eliminating any mirror deformation. This reduction system is verified for SOFIA by a hydraulic axial support system for 64 support points in an optimized arrangement in four support rings. Contour line plots and the optical performance are given for this system. A dynamic analysis of the mirror and its support system has shown a remarkable insensitivity of the system against axial accelerations. This mechanism is studied and explained using a simplified beam model. The lateral support system does not carry the mirror at the outer rim as usually designed, but at the mirror's rear side in combination with the axial support system. All the lateral support forces are momentum compensated to transfer the actual force position into the flexural neutral line of the mirror. The self balancing hydraulic support system can be superposed by an active correction system, which adds forces generated by a lever system with a motor driven dead weight. This system can be used to correct long wave errors of the mirror or flight related shape errors of time independent behavior.

Paper Details

Date Published: 1 November 1990
PDF: 12 pages
Proc. SPIE 1340, Cryogenic Optical Systems and Instruments IV, (1 November 1990); doi: 10.1117/12.23043
Show Author Affiliations
Hans-Juergen Meier, Carl Zeiss (Germany)


Published in SPIE Proceedings Vol. 1340:
Cryogenic Optical Systems and Instruments IV
Ramsey K. Melugin; Gerald R. Pruitt, Editor(s)

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