Bibcode
Sanchez Almeida, J.; Martinez Pillet, V.; Kneer, F.
Bibliographical reference
Astronomy and Astrophysics Supplement, v.113, p.359
Advertised on:
10
1995
Citations
10
Refereed citations
9
Description
We have put into practice the technique to minimize the instrumental
polarization (IP) of coude telescopes proposed by Martinez Pillet &
Sanchez Almeida (1991): a λ/2-plate inserted into the optical
path, with the proper orientation, cancels the IP. The compensation of
the Gregory-Coude Telescope at the Observatorio del Teide turns out to
fulfil theoretical expectations. Empirical tests at 630nm demonstrate
that its IP decreases by a factor ~4. We show that the residual IP is
not intrinsic to the method but it is due to the limited precision of
the retarder presently used. In addition, observations indicate that the
insertion of the λ/2-plate does not noticeably deteriorate the
optical quality of the whole telescope. In short, this work proves the
practical soundness of the λ/2-plate technique to reduce IP.