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Proceedings Paper

Metrology concept design of the GAIA basic angle monitoring system
Author(s): Marielle van Veggel; Rob Vink; Nick Rosielle; Henk Nijmeijer; Arno A. Wielders
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Paper Abstract

The GAIA satellite, scheduled for launch in 2010, will make a highly accurate map of our Galaxy. It will measure the position of stars with an accuracy of 50 prad using two telescopes, which are positioned under a 'basic' angle between the the lines-of-sight of the telescopes of 106°. With a Basic Angle Monitoring system, variations of this angle will be measured with 5 prad accuracy, to correct for these variations on the measured position of stars. A conceptual design of the Basic Angle Monitoring system is presented. Two pairs of parallel laser bundles are sent to the telescopes, which create two interference patterns. If the basic angle varies, the interference patterns will shift. The optical design is such that the rotation of one pair of beams with respect to the other pair, does not affect the measured basic angle. The position stability requirement of the mirrors is a maximum shift of 1 pm in 6 hours. For material stability and good thermal and mechanical properties, Silicon Carbide has been chosen. The structural design is such that the design is as much monolithic as possible. The alignment is performed along the horizontal plane with external and removable alignment mechanisms. The components are locked by adhesives.

Paper Details

Date Published: 29 September 2004
PDF: 12 pages
Proc. SPIE 5495, Astronomical Structures and Mechanisms Technology, (29 September 2004); doi: 10.1117/12.551082
Show Author Affiliations
Marielle van Veggel, Technische Univ. Eindhoven (Netherlands)
Rob Vink, TNO TPD (Netherlands)
Nick Rosielle, Technische Univ. Eindhoven (Netherlands)
Henk Nijmeijer, Technische Univ. Eindhoven (Netherlands)
Arno A. Wielders, TNO TPD (Netherlands)

Published in SPIE Proceedings Vol. 5495:
Astronomical Structures and Mechanisms Technology
Joseph Antebi; Dietrich Lemke, Editor(s)

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