Bibcode
Gonte, F.; Yaitskova, N.; Derie, F.; Constanza, A.; Brast, R.; Buzzoni, B.; Delabre, B.; Dierickx, P.; Dupuy, C.; Esteves, R.; Frank, C.; Guisard, S.; Karban, R.; Koenig, E.; Kolb, J.; Nylund, M.; Noethe, L.; Surdej, I.; Courteville, A.; Wilhelm, R.; Montoya, L.; Reyes, M.; Esposito, S.; Pinna, E.; Dohlen, K.; Ferrari, M.; Langlois, M.
Bibliographical reference
Advanced Wavefront Control: Methods, Devices, and Applications III. Edited by Gruneisen, Mark T.; Gonglewski, John D.; Giles, Michael K. Proceedings of the SPIE, Volume 5894, pp. 306-317 (2005).
Advertised on:
8
2005
Citations
6
Refereed citations
4
Description
The future European Extremely Large Telescope will be composed of one or
two giant segmented mirrors (up to 100 m of diameter) and of several
large monolithic mirrors (up to 8 m in diameter). To limit the
aberrations due to misalignments and defective surface quality it is
necessary to have a proper active optics system. This active optics
system must include a phasing system to limit the degradation of the PSF
due to misphasing of the segmented mirrors. We will present the lastest
design and development of the Active Phasing Experiment that will be
tested in laboratory and on-sky connected to a VLT at Paranal in Chile.
It includes an active segmented mirror, a static piston plate to
simulate a secondary segmented mirror and of four phasing wavefront
sensors to measure the piston, tip and tilt of the segments and the
aberrations of the VLT. The four phasing sensors are the Diffraction
Image Phase Sensing Instrument developed by Instituto de Astrofisica de
Canarias, the Pyramid Phasing Sensor developed by Arcetri Astrophysical
Observatory, the Shack-Hartmann Phasing Sensor developed by the European
Southern Observatory and the Zernike Unit for Segment phasing developed
by Laboratoire d'Astrophysique de Marseille. A reference measurement of
the segmented mirror is made by an internal metrology developed by
Fogale Nanotech. The control system of Active Phasing Experiment will
perform the phasing of the segments, the guiding of the VLT and the
active optics of the VLT. These activities are included in the Framework
Programme 6 of the European Union.