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Contrôle des télescopes automatiques et des grands interféromètres stellaires terrestres et spatiaux :
cas du télescope prototype OVLA à monture sphérique et optique active

Abstract : Project OVLA (Optical Very Large Array) consists in a large stellar interferometer designed to provide high resolution snapshot images in visible and infrared wavelengths. It is composed of 27 mobile telescopes distributed on a flat site of several kilometres. Indeed, the mobility of the telescopes during the observation maintains the optical paths equality as well as the u-v plane coverage uniformity.

Robotic, stable, light weight and compact telescopes are needed for such an interferometer. A 1.52m prototype telescope is under construction at OHP. It features a spherical mount and an active mirror. For budgetary purposes, the mirror is made of 24mm-thick ordinary glass. The deformations of the mirror are then compensated by 29 actuators.

My preliminary work was the study and the realisation of the control systems of the mount and of the active mirror. I also detail the heating system of the mirror surface, which allows an efficient compensation of the thermal deformations.

The first results obtained on the sky with the active mirror in the spherical mount are presented. The future as well as the technological and industrial repercussions of the OVLA prototype telescope are also discussed.

Moreover, I study the principle of the "densified pupil" (Labeyrie, 1996) which improves considerably the contrast of the images obtained at the focus of an interferometer. I show that it is possible to transform the initial concept of OVLA into a true hypertelescope.

Lastly, within the TPF study ordered by NASA, I present a model of solar sails to point and cophase a space interferometer composed of several free-flyers. Such space interferometers should provide direct images of exoplanets.
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Contributor : Olivier Lardière <>
Submitted on : Wednesday, January 11, 2006 - 2:00:53 PM
Last modification on : Monday, May 18, 2020 - 2:30:18 PM
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Olivier Lardière. Contrôle des télescopes automatiques et des grands interféromètres stellaires terrestres et spatiaux :
cas du télescope prototype OVLA à monture sphérique et optique active. Astrophysique [astro-ph]. Université de Provence - Aix-Marseille I, 2000. Français. ⟨tel-00011346⟩

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