Issue |
Astron. Astrophys. Suppl. Ser.
Volume 128, Number 2, March I 1998
|
|
---|---|---|
Page(s) | 369 - 375 | |
DOI | https://doi.org/10.1051/aas:1998148 | |
Published online | 15 March 1998 |
An imaging polarimeter (IMPOL) for multi-wavelength observations
1
Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune - 411 007, India
2
Department of Physics, Assam University, Silchar - 788 001, India
Send offprint request to: A.N. Ramaprakash
Received:
20
January
1997
Accepted:
11
July
1997
Taking advantage of the advances in array detector technology,
an imaging polarimeter (IMPOL) has been constructed for measuring linear
polarization in the wavelength band from 400-800 nm. It makes
use of a Wollaston prism as the analyzer to measure
simultaneously the two orthogonal polarization components that define a
Stoke's parameter. An achromatic half-wave plate is used to rotate the
plane of polarization with respect to the axis of the analyzer so that the
second Stoke's parameter also can be determined. With a field of view
corresponding to about for a
20/D 1.2 m, f/13
telescope, a sensitive, liquid-
cooled CCD camera as the
detector and a built-in acquisition and guidance unit, the instrument can be used for studying stellar fields or extended objects with an angular
resolution of
. The instrumental polarization is less than
0.05% and the accuracies of measurement are primarily limited by photon
noise for typical observations.
Key words: instrumentation: polarimeters / techniques: polarimetry / polarization
© European Southern Observatory (ESO), 1998