Issue |
A&A
Volume 399, Number 1, February III 2003
|
|
---|---|---|
Page(s) | 385 - 394 | |
Section | Astronomical instrumentation | |
DOI | https://doi.org/10.1051/0004-6361:20021744 | |
Published online | 05 February 2003 |
Calibration of NAOS and CONICA static aberrations
Experimental results
1
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany e-mail: hartung@mpia.de
2
Office National d'Études et de Recherches Aérospatiales, Département d'Optique Théorique et Appliquée, BP 72, 92322 Châtillon Cedex, France
3
Laboratoire des Signaux et Systèmes, École Supérieure d'Électricité, Plateau de Moulon, 91192 Gif-sur-Yvette, France
4
Observatoire Paris-Meudon, LESIA, Place Jules Janssen, 92195 Meudon Cedex, France
Corresponding author: T. Fusco, thierry.fusco@onera.fr
Received:
16
July
2002
Accepted:
25
October
2002
NAOS is the first adaptive optics (AO) system of the Very Large Telescope and will provide CONICA with diffraction-limited images. CONICA is a near infrared camera that offers a variety of imaging and spectroscopic observing modes. A technique will be described to benefit of the AO system to correct not only for atmospheric turbulence but also for the internal optical aberrations of the high-resolution camera and the beam splitters of NAOS. The aberrant optical components in the light path of CONICA as well as the beam splitters are outside of the AO loop and therefore no self-acting correction is possible. Independently of the AO wavefront sensor, a separate measurement of these aberrations using a method called phase diversity allows one to predict for a certain instrument configuration the corresponding aberrations. They are quantified by sets of Zernike coefficients that are rendered to the adaptive optics. This technique turns out to be very flexible and results in a further improvement of the optical overall performance. The application of phase diversity to the instrument is investigated in a preceding paper (Blanc et al. 2003). In the present paper we present in detail the instrumental implementation of phase diversity, the obtained calibration results, and the achieved gain in optical performance.
Key words: instrumentation: adaptive optics
© ESO, 2003
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