A wavefront sensor for the Wendelstein Fraunhofer Telescope

Shao Ming Hu; Frank Grupp; Florian Lang-Bardl; Ulrich Hopp; Ralf Bender; Wolfgang Mitsch; Claus Gössl

doi:10.1117/12.2073146

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18 November 2014 A wavefront sensor for the Wendelstein Fraunhofer Telescope

Shao Ming Hu, Frank Grupp, Florian Lang-Bardl, Ulrich Hopp, Ralf Bender, Wolfgang Mitsch, Claus Gössl

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Proceedings Volume 9298, International Symposium on Optoelectronic Technology and Application 2014: Imaging Spectroscopy; and Telescopes and Large Optics; 92981S (2014) https://doi.org/10.1117/12.2073146
Event: International Symposium on Optoelectronic Technology and Application 2014, 2014, Beijing, China

Abstract

A modern 2-m telescope is in comissioning phase at Wendelstein Observatory since late 2013. In order to make full use of good seeing conditions in Wendelstein, many measures were taken to reduce the image aberration to get the best image quality. Due to its fast primary mirror, the telescope image quality depends critically on the secondary mirror alignment. Thus a scheme of quick and accurate alignment of the secondary mirror is desired for the telescope system. We will utilize a Shack-Hartmann wavefront sensor (SHS) to optimize the alignment for a basically well aligned telescope system. The principle of the image aberration measurement using SHS is shortly re-introduced with this paper. Merit function regression method can be used to align the secondary mirror of the telescope system using Zernike coefficients derived from the reconstructed wavefront. The principle of merit function regression method is described in this paper. Optical and mechanical layout of this telescope alignment system is also shown. A temperature stabilized box for SHS was designed to keep the wavefront measurement precision of a commercial SHS system in the harsh conditions of an observatory site. Mechanical design and temperature control system of the temperature stabilized box are also illustrated. The deviation of the temperature is within 0.04 degree from the first test of the temperature stabilization experiment, which is good enough to decrease the wavefront measurement error produced by environmental temperature variation.

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Shao Ming Hu, Frank Grupp, Florian Lang-Bardl, Ulrich Hopp, Ralf Bender, Wolfgang Mitsch, and Claus Gössl "A wavefront sensor for the Wendelstein Fraunhofer Telescope", Proc. SPIE 9298, International Symposium on Optoelectronic Technology and Application 2014: Imaging Spectroscopy; and Telescopes and Large Optics, 92981S (18 November 2014); https://doi.org/10.1117/12.2073146

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