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Proceedings Paper

Diffractional treatment of curvature sensing in segmented mirror telescopes
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Paper Abstract

Discontinuities in the wavefront phase or amplitude affect curvature sensor (CS) response. These discontinuities may be the result of an improper alignment of the elements of a segmented mirror in either piston or tip-tilt. We describe the CS response with an analytical approach based on the Fresnel approximation of the diffracted field and show that a CS is capable of detecting misalignment among segments. The response model that we present leads to a fast algorithm for the measurement of segment positions. As an application, we focus on piston co-phasing. The paper concludes with the characterization of the integrated curvature signal, which simplifies the analysis of the CS response to misalignments. The low processing time and principal memory requirements of the algorithm make it suitable for extremely large telescopes (ELTs).

Paper Details

Date Published: 4 February 2003
PDF: 11 pages
Proc. SPIE 4837, Large Ground-based Telescopes, (4 February 2003); doi: 10.1117/12.457992
Show Author Affiliations
Jose Maria Rodriguez-Gonzalez, Instituto de Astrofisica de Canarias (Spain)
Jesus Jimenez Fuensalida, Instituto de Astrofisica de Canarias (Spain)

Published in SPIE Proceedings Vol. 4837:
Large Ground-based Telescopes
Jacobus M. Oschmann; Larry M. Stepp, Editor(s)

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