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Tackling down the low wind effect on SPHERE instrument

Sauvage, Jean François and Fusco, Thierry and Lamb, Masen and Girard, Julien and Brinkmann, Martin and Guesalaga, Andres and Wizinowich, Peter and O'Neal, Jared and N'Diaye, Mamadou and Vigan, Arthur and Mouillet, David and Beuzit, Jean-Luc and Kasper, Markus and Le Louarn, Miska and Milli, Julien and Dohlen, Kjetil and Neichel, Benoît and Bourget, Pierre and Haguenauer, Pierre and Mawet, Dimitri (2016) Tackling down the low wind effect on SPHERE instrument. In: Adaptive Optics Systems V. Proceedings of SPIE. No.9909. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 990916. ISBN 9781510601970.

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SPHERE is the VLT second generation planet hunter instrument. Installed since May 2014 on UT3, the system has been commissioned and verified for more than one year now and routinely delivers unprecedented images of star surroundings, exoplanets and dust disks. The exceptional performance required for this kind of observation makes the appointment: a repeatable Strehl Ratio of 90% in H band, a rough contrast level of 10-5@0.5 arcsec, and reaches 10-6 at the same separation after differential imaging (SDI, ADI). The instrument also presents high contrast levels in the visible and an unprecedented 17mas diffraction-limited resolution at 0.65 microns wavelength. SAXO is the SPHERE XAO system, allowing the system to reach its final detectivity. Its high performance and therefore highly sensitive capacities turns a new eye on telescope environment. Even if XAO performance are reached as expected, some unexpected limitations are here described and a first work around is proposed and discussed. Spatial limitation: wave-front aberrations have been identified, deviating from kolmogorov statistics, and therefore not easily seen and compensated for by the XAO system. The impact of this limitations results in a degraded performance in some particular low wind conditions. Solutions are developed and tested on sky to propose a new operation procedure reducing this limitation. Temporal limitation: high amplitude vibrations on the low order modes have been issued, due to telescope environment and XAO behaviour. Again, a solution is developed and an assessment of its performance is dressed. The potential application of these solutions to E-ELT is proposed.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Girard, Julien0000-0001-8627-0404
Wizinowich, Peter0000-0002-1646-442X
N'Diaye, Mamadou0000-0002-1721-3294
Vigan, Arthur0000-0002-5902-7828
Milli, Julien0000-0001-9325-2511
Mawet, Dimitri0000-0002-8895-4735
Additional Information:© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).
Subject Keywords:High contrast imaging, adaptive optics, dome seeing
Series Name:Proceedings of SPIE
Issue or Number:9909
Record Number:CaltechAUTHORS:20180615-154904987
Persistent URL:
Official Citation:Jean-François Sauvage, Thierry Fusco, Masen Lamb, Julien Girard, Martin Brinkmann, Andres Guesalaga, Peter Wizinowich, Jared O'Neal, Mamadou N'Diaye, Arthur Vigan, David Mouillet, Jean-Luc Beuzit, Markus Kasper, Miska Le Louarn, Julien Milli, Kjetil Dohlen, Benoît Neichel, Pierre Bourget, Pierre Haguenauer, Dimitri Mawet, "Tackling down the low wind effect on SPHERE instrument", Proc. SPIE 9909, Adaptive Optics Systems V, 990916 (26 July 2016); doi: 10.1117/12.2232459;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87169
Deposited By: George Porter
Deposited On:18 Jun 2018 15:37
Last Modified:11 Oct 2019 01:39

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