Optical polarimetric observations of black hole binary Cyg X-1 with DIPol-2

The dataset contains raw polarimetric FITS images of black hole X-ray binary Cyg X-1 (and surrounding field), obtained with the DIPol-2 optical CCD polarimeter in three (BVR) filters while mounted on the remotely operated Tohoku 60 cm (T60) telescope at the Haleakala Observatory, Hawaii. The data were collected over 5 observing nights during the week 2022 May 15–21 for about 4 hours each night. During each observing night, a set of calibration images were also obtained. These typically include 7 dark and 7 bias images per filter per night. Bias and dark FITS files have `bias` or `dark` labels in their names.