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Proceedings Paper

Performances and results on the sky of the NAOS visible wavefront sensor
Author(s): Philippe Feautrier; Gerard Rousset; Reinhold J. Dorn; Cyril Cavadore; Julien Charton; Claudio Cumani; Thierry Fusco; Norbert N. Hubin; Pierre Y. Kern; Jean-Luis Lizon; Yves Magnard; Pascal Puget; Didier Rabaud; Patrick Rabou; Eric Stadler
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Paper Abstract

The NAOS adaptive optics system was installed in December 2001 on the Nasmyth focus of the ESO VLT. It includes two wavefront sensors: one is working at IR wavelength analysis and the other at visible wavelengths. This paper describes the NAOS Visible Wave Front Sensor based on a Shack-Hartman principle and its performances as measured on the sky. This wavefront sensor includes within a continuous flow liquid nitrogen cryostat: 1) a low noise fast readout CCD camera controlled by the ESO new generation CCD system FIERA using a fast frame rate EEV/Marconi CCD-50 focal plane array. This 128×128 pixels focal plane array has a readout noise of 3 e- at 50 kilopixel/sec/port. FIERA provides remotely controlled readout modes with optional binning, windowing and flexible integration time. 2) two remotely exchangeable micro-lens arrays (14×14 and 7×7 micro-lenses) cooled at the CCD temperature ( -100 °C) within the cryostat. The CCD array is directly located in the micro lenses focal plane at a few millimeters apart without relay optics. 3) Additional opto-mechanical functions are also provided (atmospheric dispersion compensator, flux level control, field of view limitation). On sky performances of the wavefront sensor are presented. Adaptive Optics corrections was obtained with a reference star as faint as a visible magnitude 17 with a band-path of 40 Hz in close loop.

Paper Details

Date Published: 7 February 2003
PDF: 9 pages
Proc. SPIE 4839, Adaptive Optical System Technologies II, (7 February 2003); doi: 10.1117/12.458945
Show Author Affiliations
Philippe Feautrier, Observatoire de Grenoble/UJF (France)
Gerard Rousset, ONERA (France)
Reinhold J. Dorn, European Southern Observatory (Germany)
Cyril Cavadore, European Southern Observatory (Germany)
Julien Charton, Observatoire de Grenoble/UJF (France)
Claudio Cumani, European Southern Observatory (Germany)
Thierry Fusco, ONERA (France)
Norbert N. Hubin, European Southern Observatory (Germany)
Pierre Y. Kern, Observatoire de Grenoble/UJF (France)
Jean-Luis Lizon, European Southern Observatory (Germany)
Yves Magnard, Observatoire de Grenoble/UJF (France)
Pascal Puget, Observatoire de Grenoble/UJF (France)
Didier Rabaud, ONERA (France)
Patrick Rabou, Observatoire de Grenoble/UJF (France)
Eric Stadler, Observatoire de Grenoble/UJF (France)


Published in SPIE Proceedings Vol. 4839:
Adaptive Optical System Technologies II
Peter L. Wizinowich; Domenico Bonaccini, Editor(s)

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