We describe the HIgh Precision Polarimetric Instrument (HIPPI), a polarimeter built at UNSW Australia and used on the Anglo-Australian Telescope (AAT). HIPPI is an aperture polarimeter using a ferro-electric liquid crystal modulator. HIPPI measures the linear polarization of starlight with a sensitivity in fractional polarization of ~4 x 10−6 on low polarization objects and a precision of better than 0.01% on highly polarized stars. The detectors have a high dynamic range allowing observations of the brightest stars in the sky as well as much fainter objects. The telescope polarization of the AAT is found to be 48 ± 5 x 10−6 in the g' band.
@article{arxiv.1503.02236,
title = {A high-sensitivity polarimeter using a ferro-electric liquid crystal modulator},
author = {Jeremy Bailey and Lucyna Kedziora-Chudczer and Daniel V. Cotton and Kimberly Bott and J. H. Hough and P. W. Lucas},
journal= {arXiv preprint arXiv:1503.02236},
year = {2015}
}