Title:
Using single-mode fibers to monitor fast Strehl ratio fluctuations. Application to a 3.6 m telescope corrected by adaptive optics
Authors:
Coudé du Foresto, V.; Faucherre, M.; Hubin, N.; Gitton, P.
Affiliation:
AA(Observatoire de Paris/DESPA, 5 place Jules Janssen, 92195 Meudon Cedex, France), AB(2 rue de la chicane, 34130 Saint-Aunès, France), AC(European Southern Observatory, Karl-Schwarzschildstrabeta e # 2, D-85748 Garching bei München, Germany), AD(European Southern Observatory, Karl-Schwarzschildstrabeta e # 2, D-85748 Garching bei München, Germany)
Journal:
Astronomy and Astrophysics Supplement, v.145, p.305-310 (A&AS Homepage)
Publication Date:
08/2000
Origin:
A&AS
A&A Keywords:
TELESCOPES, TECHNIQUES: INTERFEROMETRIC, ADAPTIVE OPTICS, INSTRUMENTATION: LARGE TELESCOPES, OPTICAL FIBERS: SINGLE-MODE, INFRARED: GENERAL
Abstract Copyright:
(c) 2000: The European Southern Observatory (ESO)
Bibliographic Code:
2000A&AS..145..305C

Abstract

The theory of starlight coupling into single-mode fibers is reviewed to show how i) the central obstruction in a telescope pupil deteriorates coupling efficiency much more than one would expect from the loss of collecting area, and ii) a single-mode fiber and a photometer can be used to monitor fast Strehl ratio fluctuations. This last point is illustrated with experimental data obtained at the 3.6 m La Silla telescope corrected with the ADONIS adaptive optics system. A 37x gain in coupling efficiency was demonstrated by turning on the adaptive optics system, but periodic fluctuations in the coupled signal revealed a vibration of the telescope tube that could not have been detected otherwise.