Polarization position angle standard stars : a reassessment of θ and its variability for seventeen stars based on a decade of observations
Observations of polarization position angle (θ) standards made from 2014 to 2023 with the High Precision Polarimetric Instrument (HIPPI) and other HIPPI-class polarimeters in both hemispheres are used to investigate their variability. Multiband data were first used to thoroughly recalibrate the instrument performance by bench-marking against carefully selected literature data. A novel co-ordinate