Optical polarimetric observations of low-mass X-ray black hole binary MAXI J1820+070 during 2019-2021 (Q6692424)

The dataset contains raw polarimetric FITS images of the low-mass X-ray black hole binary MAXI J1820+070 (and surrounding field), obtained by the DIPol-UF optical CCD polarimeter in three (BVR) filters while mounted on the 2.56m Nordic Optical Telescope. The data were collected over 5 observing runs throughout 2019--2021. 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 (sometimes more if weather conditions or instrument settings changed during observations). Bias and dark FITS files have `_bias` or `_dark` labels in their names, as well as FITS key `IMAGETYP` set to either `Bias Frame` or `Dark Frame`, respectively.