A multichannel Pockels cell spectropolarimeter for the Anglo-Australian Telescope

• Published in: Monthly notices of the Royal Astronomical Society Vol. 209; no. 3; pp. 655 - 664
• Main Authors: McLean, I. S., Heathcote, S. R., Paterson, M. J., Fordham, J., Shortridge, K.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford University Press 01.08.1984; Blackwell Science
• Subjects: Astronomical and space-research instrumentation; Astronomy; Earth, ocean, space; Exact sciences and technology; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Polarimeter; Telescope
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/209.3.655

A powerful new faint-object spectropolarimeter for the 3.9-m Anglo-Australian Telescope is described. It employs an existing spectrograph and Image Photon Counting System (IPCS) together with a custom-built Pockels cell (electro-optic) polarimeter. Quarter-wave plates may be introduced above the cell and thus both linear and circular polarization may be measured. A very high polarimetric efficiency is obtained over the entire optical spectrum; peak values of 96 per cent are observed. Instrumental polarization is negligible and the measurement precision is limited only by photon counting statistics. Simultaneous spectrophotometry is possible with only a modest loss in sensitivity compared with the normal spectroscopic mode. Examples of observations are described.