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Proceedings Paper

Atmospheric parameter estimation from AO wavefront sensing data: application of the FADE method with NACO
Author(s): Elisabeth Brunner; Julien H. Girard
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Paper Abstract

The performance of a ground based telescope can depend greatly on the coherence time, a site and time varying parameter determining the required reaction bandwidth of an Adaptive Optics system. Recently, Fast Defocus (FADE), a method which measures the coherence time from defocus fluctuations in a small telescope introduced by atmospheric turbulence has been presented. In this work, FADE was implemented for the Nasmyth Adaptive Optics System (NAOS) of the VLT's UT4 to demonstrate suitability for large scale telescopes. Estimates of the coherence time for an examplary set of AO loop data were compared to results obtained with the DIMM and MASS instruments, showing good agreement which justify a future in depth analysis for large AO loop data samples provided by NAOS as well as the VLT's Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument.

Paper Details

Date Published: 13 August 2014
PDF: 7 pages
Proc. SPIE 9148, Adaptive Optics Systems IV, 914861 (13 August 2014); doi: 10.1117/12.2055614
Show Author Affiliations
Elisabeth Brunner, Delft Univ. of Technology (Netherlands)
Julien H. Girard, European Southern Observatory (Chile)

Published in SPIE Proceedings Vol. 9148:
Adaptive Optics Systems IV
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)

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