Issue |
Astron. Astrophys. Suppl. Ser.
Volume 117, Number 1, May II 1996
|
|
---|---|---|
Page(s) | 167 - 178 | |
DOI | https://doi.org/10.1051/aas:1996148 | |
Published online | 15 May 1996 |
Optical design, modelling and tolerancing of a Fizeau interferometer dedicated to astrometry
1
DESPA, Observatoire de Paris, F-92195 Meudon Cedex, France
2
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, U.S.A.
Received:
19
September
1995
Accepted:
2
November
1995
Space-based interferometers dedicated to wide-angle astrometry would
dramatically increase the accuracy of angular measurements fundamental to
a wide range of astrophysical problems.
The proposed Global Astrometric Interferometer for Astrophysics (GAIA),
a continuously rotating instrument comprising two or three interferometers,
will reach the as level on more than 35 million objects.
The necessary wide field-of-view for such a precision could be obtained with
a Fizeau interferometer. We designed and modelled
a 2.6 m baseline interferometer with two 40 cm apertures,
and overall dimensions compatible with the size of the Ariane V payload
shroud. It has a ~ 1 degree diffraction limited field-of-view.
The response of the optical system to small perturbations on each optical
element is given in terms of fringe visibility, which is shown to depend mainly
on sub-aperture spot separation. The robustness of the design
to thermal, mechanical and manufacturing errors is discussed.
Key words: instrumentation: interferometers / telescopes / astrometry
© European Southern Observatory (ESO), 1996