Gaia in-orbit realignment: overview and data analysis
conference paper
The ESA Gaia spacecraft has two Shack-Hartmann wavefront sensors (WFS) on its focal plane. They are required to refocus the telescope in-orbit due to launch settings and gravity release. They require bright stars to provide good signal to noise patterns. The centroiding precision achievable poses a limit on the minimum stellar brightness required and, ultimately, on the observing time required to reconstruct the wavefront. Maximum likelihood algorithms have been developed at the Gaia SOC. They provide optimum performance according to the Cramér-Rao lower bound. Detailed wavefront reconstruction procedures, dealing with partial telescope pupil sampling and partial microlens illumination have also been developed. In this work, a brief overview of the WFS and an in depth description of the centroiding and wavefront reconstruction algorithms is provided.
Topics
TNO Identifier
463414
Publisher
Society of Photo-Optical Instrumentation Engineers
Source title
Astronomical Telescopes + Instrumentation 2012, advancing astronomy with development on all scales, 1-6 July, 2012, Amsterdam, The Netherlands
Collation
14 p.
Place of publication
Bellingham, WA, United States