Bibcode
Sanchez Almeida, J.
Bibliographical reference
Astronomy and Astrophysics (ISSN 0004-6361), vol. 292, no. 2, p. 713-721
Advertised on:
12
1994
Citations
16
Refereed citations
12
Description
This work quantifies the influence of the terrestrial atmosphere on the
instrumental polarization (IP) of telescopes. Our numerical simulations
show that seeing mostly induces a random crosstalk between Stokes
parameters. The main contamination affects the linear polarization
signals and is due to mixing with intensity. In general, circular
polarization signals are less corrupted by atmospheric effects. We have
analyzed the IP considering the imaging mirrors and the entrance window
of a particular instrument, namely the Large Earth-based Solar Telescope
(LEST). Crosstalks up to 2 x 10-2 (window) and up to 2 x
10-3 (mirrors) occur in short-exposure images. This level of
IP is largely reduced by increasing the exposure time or the pixel size.
Means for extrapolating the IP of LEST to other instruments are
provided. Using them, the dependence of the seeing-induced IP on
wavelength, telescope size etc. is briefly examined.