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Proceedings Paper

Precessions process for efficient production of aspheric optics for large telescopes and their instrumentation
Author(s): David D. Walker; A. T. H. Beaucamp; Richard G. Bingham; David Brooks; Richard Freeman; Sowoon Kim; Andrew King; Gerry McCavana; Roger Morton; David Riley; John Simms
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Paper Abstract

We summarize the reasons why aspheric surfaces, including non-rotationally-symmetric surfaces, are increasingly important to ground and space-based astronomical instruments, yet challenging to produce. We mainly consider the generic problem of producing aspheres, and then lightweight segments for the primary mirror of an Extremely Large Telescope. We remark on the tension between manufacturability of spherical segments, and performance with aspheric segments. This provides the context for our presentation of the novel Precessions process for rapid polishing and form-correction of aspheric surfaces. We outline why this is a significant step beyond previous methods to automate aspheric production, and how it has resulted in a generalized, scaleable technology that does not require high capital-value tooling customized to particular types of optical form. We summarize implementation in the first two automated CNC machines of 200mm capacity, followed by the first 600mm machine, and the current status of the process-development program. We review quantitative results of polishing trials, including materials relevant to large and instrumentation optics. Finally, we comment on the potential of the technology for space optics and for removing quilting in honeycomb substrates.

Paper Details

Date Published: 30 January 2003
PDF: 12 pages
Proc. SPIE 4842, Specialized Optical Developments in Astronomy, (30 January 2003); doi: 10.1117/12.456677
Show Author Affiliations
David D. Walker, Univ. College London (United Kingdom)
Zeeko Ltd. (United Kingdom)
A. T. H. Beaucamp, Zeeko Ltd. (United Kingdom)
Richard G. Bingham, Univ. College London (United Kingdom)
David Brooks, Univ. College London (United Kingdom)
Richard Freeman, Zeeko Ltd. (United Kingdom)
Sowoon Kim, Yonsei Univ. (South Korea)
Andrew King, Univ. College London (United Kingdom)
Gerry McCavana, Zeeko Ltd. (United Kingdom)
Roger Morton, Zeeko Ltd. (United Kingdom)
David Riley, Zeeko Ltd. (United Kingdom)
John Simms, Zeeko Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 4842:
Specialized Optical Developments in Astronomy
Eli Atad-Ettedgui; Sandro D'Odorico, Editor(s)

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