RoboPol: a four-channel optical imaging polarimeter
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 485:2 (2019) 2355-2366
Authors:
AN Ramaprakash, CV Rajarshi, HK Das, P Khodade, D Modi, G Panopoulou, S Maharana, D Blinov, E Angelakis, C Casadio, L Fuhrmann, T Hovatta, S Kiehlmann, OG King, N Kylafis, A Kougentakis, A Kus, A Mahabal, A Marecki, I Myserlis, G Paterakis, E Paleologou, I Liodakis, I Papadakis, I Papamastorakis, V Pavlidou, E Pazderski, TJ Pearson, ACS Readhead, P Reig, A Słowikowska, K Tassis, JA Zensus
Abstract:
ABSTRACT
We present the design and performance of RoboPol, a four-channel optical polarimeter operating at the Skinakas Observatory in Crete, Greece. RoboPol is capable of measuring both relative linear Stokes parameters q and u (and the total intensity I) in one sky exposure. Though primarily used to measure the polarization of point sources in the R band, the instrument features additional filters (B, V, and I), enabling multiwavelength imaging polarimetry over a large field of view (13.6′ × 13.6′). We demonstrate the accuracy and stability of the instrument throughout its 5 yr of operation. Best performance is achieved within the central region of the field of view and in the R band. For such measurements the systematic uncertainty is below 0.1 per cent in fractional linear polarization, p (0.05 per cent maximum likelihood). Throughout all observing seasons the instrumental polarization varies within 0.1 per cent in p and within ∼1° in polarization angle.
