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Proceedings Paper

Alignment and integration of ASSIST: a test bench for VLT adaptive optics facility
Author(s): Atul Deep; Robin Arsenault; Wilfried Boland; Bernard Delabre; Norbert Hubin; Paolo La Penna; Pierre-Yves Madec; Frank Molster; Remko Stuik; Sebastien Tordo; Emiel Wiegers
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Paper Abstract

ASSIST, The Adaptive Secondary Setup and Instrument STimulator, is being developed to provide a testing facility for the ESO Adaptive Optics Facility (AOF). It will allow the off-telescope testing of three elements of the VLT AOF; the Deformable Secondary Mirror (DSM) and the AO systems for MUSE and HAWK-I (GALACSI and GRAAL). The core of ASSIST consists of a 2-mirror setup (AM1-AM2) allowing the on-axis test of the DSM in interferometric mode. However, during the initial stages of ASSIST integration, DSM would not be present. This makes the task of aligning AM1-AM2 to within an accuracy of 0.05mm/1 arcmin rather challenging. A novel technique known as Shack-Hartmann method has been developed and tested in the lab for this purpose. A Shack Hartmann wavefront sensor will be used to measure the mis-alignment between AM1-AM2 by recording the coma and astigmatism in the presence of large spherical aberration introduced because of tilt/decenter of AM2 with respect to AM1. Thereafter, 20 optical components including lenses, flat mirrors and beam-splitter cubes divided into five sub-assemblies should be aligned to AM1-AM2- DSM axis which ultimately passes through the mechanical axis of large AMOS rotator.

Paper Details

Date Published: 3 September 2010
PDF: 15 pages
Proc. SPIE 7793, Optical System Alignment, Tolerancing, and Verification IV, 77930L (3 September 2010); doi: 10.1117/12.860491
Show Author Affiliations
Atul Deep, Leiden Univ. (Netherlands)
Robin Arsenault, European Southern Observatory (Germany)
Wilfried Boland, Leiden Univ. (Netherlands)
Bernard Delabre, European Southern Observatory (Germany)
Norbert Hubin, European Southern Observatory (Germany)
Paolo La Penna, European Southern Observatory (Germany)
Pierre-Yves Madec, European Southern Observatory (Germany)
Frank Molster, Leiden Univ. (Netherlands)
Remko Stuik, Leiden Univ. (Netherlands)
Sebastien Tordo, European Southern Observatory (Germany)
Emiel Wiegers, Leiden Univ. (Netherlands)

Published in SPIE Proceedings Vol. 7793:
Optical System Alignment, Tolerancing, and Verification IV
José Sasián; Richard N. Youngworth, Editor(s)

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