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Proceedings Paper

A very accurate filter wheel for a large field IR imager
Author(s): J. L. Lizon
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Paper Abstract

HAWK-I is a near-infrared imager with a relatively large field of view. Two filter wheels with 6 positions each offer a choice of 10 filters. The filters are directly in front of the detector, a mosaic of 2 × 2HAWAII 2RG 2048×2048 pixels detectors. A rather high positioning reproducibility (< 6 arc sec) is required in order to avoid any disagreement caused by subtraction of eventual fix pattern on the filters. The document describes various drive systems which have been tested in order to reach the specified positioning reproducibility. This includes an interesting dissipation free locking system combining electro magnet and permanent magnet. Every solution is discussed and the performances measured in the laboratory during a long campaign of test are exposed. We also address the choice of other critical components like the ball bearings, mounting of the filters and cooling of the wheels.

Paper Details

Date Published: 22 July 2010
PDF: 6 pages
Proc. SPIE 7739, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation, 77393G (22 July 2010); doi: 10.1117/12.856093
Show Author Affiliations
J. L. Lizon, European Southern Observatory (Germany)

Published in SPIE Proceedings Vol. 7739:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)

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