Abstract

Tomographic AO (or Wide Field AO) systems use LGS to build a 3D model of turbulence, but rely on NGS for low order sensing. .To preserve reasonable sky coverage, each photon coming from the NGS to sense Tip Tilt has to be optimally exploited. That means a smart control law, a low detection noise, a concentration of the photons onto a small patch and a wave front sensor concept with favorable noise propagation. In this paper, we describe the system choices that were made during the E-ELT laser tomographic system ATLAS phase A study, in order to get a sky coverage as close as possible to 100%. A correct estimation of the sky coverage is therefore a key issue. We have developped a sky coverage estimation strategy based on a Besan¸con model starfield generation, a star(s) selection tool, and a careful estimation of the residual anisoplanatism (after reconstruction process between the NGSs), noise and temporal contributors. We describe the details of the procedure, and derive the ATLAS expected performance.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.