Laser Guide Star for 3.6- and 8-m telescopes: Performance and astrophysical implications |
| |
| Authors: | M Le Louarn R Foy N Hubin & M Tallon |
| |
| Institution: | ;ESO–European Southern Observatory, Karl-Schwarzschild-Straße 2, Garching bei München, D-85748 Germany,;CRAL–Centre de Recherche astronomique de Lyon, 9 av. Charles André, F-69561 Saint Genis Laval, France |
| |
| Abstract: | We have constructed an analytical model to simulate the behaviour of an adaptive optics system coupled with a sodium laser guide star. The code is applied to 3.6- and 8-m class telescopes. The results are given in terms of Strehl ratio and full width at half-maximum of the point spread function. Two atmospheric models are used, one representing good atmospheric conditions (20 per cent of the time), the other median conditions. Sky coverage is computed for natural guide star and laser guide star systems, with two different methods. The first one is a statistical approach, using stellar densities to compute the probability of finding a nearby reference. The second is a cross-correlation of a science-object catalogue and the USNO catalogue. Results are given in terms of percentage of the sky that can be accessed with given performances, and in terms of the number of science objects that can be observed, with Strehls greater than 0.2 and 0.1 in the K and J bands. |
| |
| Keywords: | atmospheric effects telescopes |
|
|
