Ground layer AO correction for the VLT MUSE project

Abstract

We describe the conceptual design of a multi-LGS based Ground Layer Adaptive Optics system feeding a visible Integral Field Spectrograph. We show that this system will be able to provide a factor two improvement in 0.2 ensquared energy. A Narrow FOV mode, delivering diffraction limited images at visible wavelengths, will be achievable by reconfiguring the four Laser Guide Stars such as to overcome the dramatic cone effect limitation at these wavelengths with single LGS. Two concepts are proposed, with and without an adaptive secondary.