Wavefront curvature sensing in a 2.5m wide-field telescope: design, analysis, and implementation for real-time correction of telescope alignment

Gregory P. Lousberg; Vincent Moreau; Olivier Pirnay; Pierre Gloesener; Carlo Flebus

doi:10.1117/12.2191274

23 September 2015 Wavefront curvature sensing in a 2.5m wide-field telescope: design, analysis, and implementation for real-time correction of telescope alignment

Gregory P. Lousberg, Vincent Moreau, Olivier Pirnay, Pierre Gloesener, Carlo Flebus

Author Affiliations +

Proceedings Volume 9626, Optical Systems Design 2015: Optical Design and Engineering VI; 962625 (2015) https://doi.org/10.1117/12.2191274
Event: SPIE Optical Systems Design, 2015, Jena, Germany

Abstract

In the framework of the design and manufacturing of a wide-field 2.5m telescope for the Observatorio Astrofisica de Javalambre (OAJ), AMOS has developed a novel wavefront sensing system that allows for real time correction of the alignment of the telescope without perturbing the acquisition of science images. The system is based on the wavefront curvature sensing (WCS) technique in which two out-of-focus images of a star are used for reconstructing the telescope wavefront error. Any deviations from the nominal wavefront error that is obtained after telescope final alignment are tracked and corrective actions can be implemented so as to optimize the telescope optical quality. The wavefront reconstruction technique and the associated corrections of the telescope alignment have been modelled and analyzed so as to validate the proposed approach before implementation in the telescope. To this aim, a bespoke coupled Zemax-Matlab model has been developed by AMOS. The model incorporates the algorithm for the telescope wavefront error reconstruction from out-of-focus images and computation of the alignment corrections in the telescope model. The justification of the wavefront sensing approach, its robustness against several sources of errors, as well as the selection of the appropriate equipment for its implementation in the telescope are discussed on the basis of this combined model.

Citation Download Citation

Gregory P. Lousberg, Vincent Moreau, Olivier Pirnay, Pierre Gloesener, and Carlo Flebus "Wavefront curvature sensing in a 2.5m wide-field telescope: design, analysis, and implementation for real-time correction of telescope alignment", Proc. SPIE 9626, Optical Systems Design 2015: Optical Design and Engineering VI, 962625 (23 September 2015); https://doi.org/10.1117/12.2191274

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