Active Phasing Experiment: preliminary results and prospects

Gonte, F.; Araujo, C.; Bourtembourg, R.; Brast, R.; Derie, F.; Duhoux, P.; Dupuy, C.; Frank, C.; Karban, R.; Mazzoleni, R.; Noethe, L.; Surdej, I.; Yaitskova, N.; Wilhelm, R.; Luong, B.; Pinna, E.,; Chueca, S.; Vigan, A.
Bibliographical reference

Ground-based and Airborne Telescopes II. Edited by Stepp, Larry M.; Gilmozzi, Roberto. Proceedings of the SPIE, Volume 7012, pp. 70120Z-70120Z-12 (2008).

Advertised on:
8
2008
Number of authors
18
IAC number of authors
1
Citations
0
Refereed citations
0
Description
The purpose of the Active Phasing Experiment, designed under the lead of ESO, is to study new phasing technologies and to validate wavefront control concepts for Extremely Large Telescopes. The Active Phasing Experiment is currently tested in the laboratory at the ESO headquarters and will be tested on sky at a Nasmyth focus of a VLT unit telescope at the end of 2008. The test bench contains four different phasing sensors which are tested in parallel to compare them under the same conditions. They have been developed by Istituto Nazionale di Astrofisica in Florenze, Instituto Astrofisica Canarias in Tenerife, Laboratoire d'Astrophysique de Marseille and ESO. It includes also an Active Segmented Mirror which simulates the segmentation of a primary mirror. A non-contact optical metrology has been developed by Fogale Nanotech to control it. The VLT focus and the VLT atmospheric conditions are simulated in the laboratory with a turbulence generator producing a seeing between 0.45 and 0.85 arcsec. Once installed on a VLT unit telescope, the control system of the Active Phasing Experiment will be able to control the phasing of the ASM, but also the guiding and the active optics of the VLT. This proceeding gives a brief summary of the opto-mechanical aspects of the Active Phasing experiment, describes its control system and gives an analysis of the preliminary results obtained in the laboratory.