Astron. Astrophys. Suppl. Ser. 144, 541-552
Modeling the imaging process in optical stellar interferometers
M. Schöller 1 - R. Wilhelm 1, 2, 3 - B. Koehler 1
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1 - European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching b. München, Germany
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Deutsches Zentrum für Luft- und Raumfahrt, Institut für Weltraumsensorik, Rutherford-Str. 2, 12489 Berlin, Germany
DaimlerChrysler Aerospace, Dornier Satellitensysteme GmbH, SX 2A, 88039 Friedrichshafen, Germany
Received December 10, 1999; accepted April 26, 2000
Optical interferometers on the ground, like ESO's Very Large Telescope
Interferometer (VLTI) and the Keck Interferometer, and in space, like
the InfraRed Space Interferometer (IRSI/Darwin)
and the Space Interferometry Mission (SIM), will bring a major
breakthrough in optical and near-infrared
high angular resolution astronomy at the beginning of the next millennium.
These instruments are complex systems with an exceptionally
interdisciplinary character involving active/adaptive optics, structural
mechanics, control engineering, electronics and various environmental
disturbances (e.g. atmospheric turbulence and absorption, wind, seismic noise).
For their design and development an approach from two sides is appropriate:
laboratory testbeds are used for experimental investigations while numerical
modeling tools perform an End-to-End instrument simulation.
We have developed a set of numerical modeling
tools to simulate the dynamic imaging process of an interferometer.
The time-dependent point spread function (PSF) mainly characterizes the imaging
performance of the instrument.
It is computed by an optomechanical model.
Based on the knowledge of the PSF the image of an incoherently
radiating extended object is computed using a Fourier optical method.
This article describes the modeling approach including an extension to more
than two interferometric beams.
Some results of simulations on the VLTI as a representative example are shown.
Key words: image processing -- optical interferometry -- observational methods -- simulation
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