Polarimetry with FOCAS
FOCAS has two types of retarders and a Wollaston prism for polarimetry. From S04A both linear and circular polarimetry modes are available. Multi-object spectropolarimetry (MOS-p) is not available because of the position-dependence of the instrumental polarization which cannot be corrected for in a simple way.
Generally, precise polarimetry/spectropolarimety requires an additional knowledge of the observing techniques and data reduction. If you are unfamiliar with polarimetric observing, you are encouraged to consult experienced observers or the FOCAS support astronomer before submitting your observing proposal.