A Finite Element Approach to the Design of the Support System for the ESO 1 M. Active Optics Experiment

A way to follow in order to reduce the weight of the primary mirror is to accept an higher ratio diameter-thickness and to find a remedy to the consequent greater deformability of the mirror by an active control system of it. A technique using closed loop active optics control has been proposed in references. In these papers, a coherent scheme of active optics control for the ESO New Technology Telescope (NTT) was presented, based on analysis of the image errors in terms of an appropriate polynomial (the ESO off-line telescope test polynomial) and the production of equivalent correction terms by force modulation of the primary axial support.