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Proceedings Paper

Optical phasing of a segmented mirror with sub-nanometer precision: experimental results of the APE Internal Metrology
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Paper Abstract

This paper presents a non-contact optical metrology measuring the pistons and tip/tilt angles of the 61 hexagonal segments of a compact-sized segmented mirror. The instrument has been developed within the scope of a design study for a European Extremely Large Telescope (E-ELT). It is used as reference sensor for cophasing of the mirror segments in closed loop control. The mirror shape is also measured by different types of stellar light-based phasing cameras whose performances will be evaluated with regard to a future E-ELT. Following a description of the system architecture, the second part of the paper presents experimental results demonstrating the level of precision: 0.48nm RMS in piston and 0.074 μrad RMS in tip and tilt.

Paper Details

Date Published: 10 July 2008
PDF: 12 pages
Proc. SPIE 7012, Ground-based and Airborne Telescopes II, 701212 (10 July 2008); doi: 10.1117/12.787377
Show Author Affiliations
Rainer Wilhelm, FOGALE nanotech (France)
Bruno Luong, FOGALE nanotech (France)
Alain Courteville, FOGALE nanotech (France)
Sébastien Estival, FOGALE nanotech (France)
Frédéric Gonté, European Southern Observatory (Germany)

Published in SPIE Proceedings Vol. 7012:
Ground-based and Airborne Telescopes II
Larry M. Stepp; Roberto Gilmozzi, Editor(s)

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