Estimation of the position of the ELT prefocal station main axis in operation

Edoardo Maria Alberto Redaelli; Carlo Zanoni; Sebastian Schmid; Paul Jolley; Martin Brinkmann; Ulrich Lampater; Steffan Lewis

doi:10.1117/12.2629187

6 September 2022 Estimation of the position of the ELT prefocal station main axis in operation

Edoardo Maria Alberto Redaelli, Carlo Zanoni, Sebastian Schmid, Paul Jolley, Martin Brinkmann, Ulrich Lampater, Steffan Lewis

Author Affiliations +

Proceedings Volume 12182, Ground-based and Airborne Telescopes IX; 121822C (2022) https://doi.org/10.1117/12.2629187
Event: SPIE Astronomical Telescopes + Instrumentation, 2022, Montréal, Québec, Canada

Conference Poster

Abstract

The Natural Guide Star Adapter (NGSA), a circular structure that is part of the Extremely Large Telescope (ELT) Pre-Focal Station (PFS) [6], defines with its rotation axis one of the reference coordinate systems of the entire telescope and has a key role in the performance of all the instruments. The PFS NGSA hosts three sensor arms (SA), which are free to move in a roughly annulus area to support to support closing control loops on natural guide stars when the light beam is controlled by the telescope[2]. The actuation of these SA’s causes a deformation of the mechanical structure and consequently uncertainty on the position and orientation of the reference coordinate system. Starting from the Finite Element Analysis (FEA) of the PFS, we develop a model that reconstructs the behavior of the structure for all the possible combinations of SA positions, and we conceive strategies for a robust definition of the reference coordinate system, as described in this paper.

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Edoardo Maria Alberto Redaelli, Carlo Zanoni, Sebastian Schmid, Paul Jolley, Martin Brinkmann, Ulrich Lampater, and Steffan Lewis "Estimation of the position of the ELT prefocal station main axis in operation", Proc. SPIE 12182, Ground-based and Airborne Telescopes IX, 121822C (6 September 2022); https://doi.org/10.1117/12.2629187

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