Gaia on-board metrology: basic angle and best focus
Abstract
The Gaia payload ensures maximum passive stability using a single material, SiC, for most of its elements. Dedicated metrology instruments are, however, required to carry out two functions: monitoring the basic angle and refocusing the telescope. Two interferometers fed by the same laser are used to measure the basic angle changes at the level of as (prad, micropixel), which is the highest level ever achieved in space. Two Shack-Hartmann wavefront sensors, combined with an ad-hoc analysis of the scientific data are used to define and reach the overall best-focus. In this contribution, the systems, data analysis, procedures and performance achieved during commissioning are presented
Keywords
Cite
@article{arxiv.1407.3729,
title = {Gaia on-board metrology: basic angle and best focus},
author = {A. Mora and M. Biermann and A. G. A. Brown and D. Busonero and L. Carminati and J. M. Carrasco and F. Chassat and M. Erdmann and W. L. M. Gielesen and C. Jordi and D. Katz and R. Kohley and L. Lindegren and W. Loeffler and O. Marchal and P. Panuzzo and G. Seabroke and J. Sahlmann and E. Serpell and I. Serraller and F. van Leeuwen and W. van Reeven and T. C. van den Dool and L. L. A. Vosteen},
journal= {arXiv preprint arXiv:1407.3729},
year = {2015}
}
Comments
18 pages, 14 figures. To appear in SPIE proceedings 9143-30. Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave