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Proceedings Paper

LAMP: a concept for the European Southern Observatory VLTI fringe sensor
Author(s): Jean Gay; Yves Rabbia
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Paper Abstract

In the framework of the development of the Very Large Telescope Interferometer (VLTI) by the European Southern Observatory (ESO) we have proposed the LAMP (Large Amplitude Modulated Path). The sensor is that part of the fringe-tracker which only provides a set of error signals reflecting Optical Path Differences (OPD) at a common focus, between collected fields, the so-called piston effect. LAMP relies on both temporal encoding of OPD on each pair of apertures and on an appropriate spatial encoding which allows simultaneous operation on several apertures. Besides, it has been designed so as to provide at the same time both coherencing error signals and cophasing error signals (these latter when allowed by the source's brightness). Such ability is based on the large amplitude used in the modulation. In this paper, after a short presentation of both initial working conditions and specific capabilities that have driven the design, we describe the principle of LAMP. We also describe a generic setup and we report performances in terms of OPD resolution (minimum detectable piston), response-time and limiting magnitude. Finally advantages and drawbacks of the design are discussed.

Paper Details

Date Published: 9 June 1994
PDF: 9 pages
Proc. SPIE 2200, Amplitude and Intensity Spatial Interferometry II, (9 June 1994); doi: 10.1117/12.177240
Show Author Affiliations
Jean Gay, Observatoire de la Cote d'Azur (France)
Yves Rabbia, Observatoire de la Cote d'Azur (France)

Published in SPIE Proceedings Vol. 2200:
Amplitude and Intensity Spatial Interferometry II
James B. Breckinridge, Editor(s)

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