Submitted by Nicolas MULLER
N. Muller(1), C. Petit(1), V. Michau(1), T. Fusco(1), C. Robert(1), J.-M. Conan(1), N. Vedrenne(1), G. Rousset(2)
(1)ONERA; (2)Observatoire de Paris Meudon
Laser Guide Stars (LGS) aim at increasing the sky coverage, highly restricted when using Adaptive Optics (AO) with Natural Guide Stars (NGS). With such an artificial object, spot elongation is a major limitation for the measurement quality when using a Wave Front Sensor (WFS). In this document, we evaluate and discuss the effects of this limitation on the measurement quality, for a 40m class telescope. We also explore the possibilities of taking these effects into account in the wave front reconstruction, and the consequences of the means proposed to reduce this elongation.