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Proceedings Paper

Developing and testing an optical alignment system for SALT’s segmented primary mirror
Author(s): Allan Wirth; Tom Gonsiorowski; Jennifer Roberts; Theresa L. Bruno; Jian Swiegers; Hitesh Gajjar; Arek Swat
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Paper Abstract

The design of the Southern African Large Telescope (SALT), which is based closely on the Hobby-Eberly Telescope (HET) at the University of Texas but includes advances incorporating lessons learned from HET, is briefly reviewed. The flowdown of requirements from the optical error budget to the primary mirror control subsystems is presented. The techniques and algorithms used by the Center of Curvature Alignment Sensor (CCAS) to measure segment tilt and piston and estimate the global radius of curvature of the primary are discussed in detail. The steps in the process that allows CCAS to capture and identify segments misaligned by more than 70 arcsec and bring them into alignment with residual errors less than 50milli-arcsec is fully described. Next, the hardware and software designs of CCAS are presented, as well as the results of laboratory performance testing. CCAS has been installed and integrated with the primary mirror control system. Performance results of the integrated system over a range of environmental conditions will be shown. Finally, the overall results of this project are summarized and suggestions for future improvements presented.

Paper Details

Date Published: 28 September 2004
PDF: 11 pages
Proc. SPIE 5489, Ground-based Telescopes, (28 September 2004); doi: 10.1117/12.551425
Show Author Affiliations
Allan Wirth, Adaptive Optics Associates (United States)
Tom Gonsiorowski, Adaptive Optics Associates (United States)
Jennifer Roberts, Adaptive Optics Associates (United States)
Theresa L. Bruno, Adaptive Optics Associates (United States)
Jian Swiegers, Southern African Astronomical Observatory (South Africa)
Hitesh Gajjar, Southern African Astronomical Observatory (South Africa)
Arek Swat, Southern African Astronomical Observatory (South Africa)

Published in SPIE Proceedings Vol. 5489:
Ground-based Telescopes
Jacobus M. Oschmann Jr., Editor(s)

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