Toward an on-sky ELT-scale sodium LGS wavefront sensing experiment

Damien Gratadour; Gérard Rousset; Éric Gendron; Olivier Fauvarque; Domenico Bonaccini Calia; Thomas Pfrommer; Richard M. Myers; Tim J. Morris

doi:10.1117/12.925720

13 September 2012 Toward an on-sky ELT-scale sodium LGS wavefront sensing experiment

Damien Gratadour, Gérard Rousset, Éric Gendron, Olivier Fauvarque, Domenico Bonaccini Calia, Thomas Pfrommer, Richard M. Myers, Tim J. Morris

Author Affiliations +

Proceedings Volume 8447, Adaptive Optics Systems III; 84473N (2012) https://doi.org/10.1117/12.925720
Event: SPIE Astronomical Telescopes + Instrumentation, 2012, Amsterdam, Netherlands

Abstract

The two first light adaptive optics (AO) instruments for the European Extremely Large Telescope (E-ELT) will both rely on several Sodium Laser Guide Stars (LGS). In using this technology, the E-ELT diameter comes with new challenges mainly raised by spot elongation. Before the final design studies of the E-ELT instruments, a Sodium LGS wavefront sensing (WFS) on-sky experiment at this scale is mandatory to provide meaningful spatial and temporal measurement error and performance evaluation. For this purpose, we propose to use CANARY, the Multi-Object AO demonstrator installed at the WHT (4.2m). CANARY is now undergoing a Rayleigh LGS upgrade and also provides natural guide star WFS. It could easily be adapted to the Sodium LGS case. Additionally, a transportable laser system, such as the one developed at ESO, positioned at a varying distance from the WHT could be used to provide off-axis launching (up to 40m), simulating the whole range of spot elongations that will be obtained on the E-ELT. Full scale simulations of a Sodium LGS WFS on the E-ELT have guided us in the definition of the experiment we are proposing. Previous simulation results in the literature have stressed that an estimate of the Sodium profile is necessary to reduce measurement error to an affordable level. Hence parallel Sodium profiling is mandatory in the proposed experiment. In this paper, we present the simulation results as well as the specifications for both the Sodium LGS WFS and profiler to be used on Canary.

Citation Download Citation

Damien Gratadour, Gérard Rousset, Éric Gendron, Olivier Fauvarque, Domenico Bonaccini Calia, Thomas Pfrommer, Richard M. Myers, and Tim J. Morris "Toward an on-sky ELT-scale sodium LGS wavefront sensing experiment", Proc. SPIE 8447, Adaptive Optics Systems III, 84473N (13 September 2012); https://doi.org/10.1117/12.925720

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available