Trends in the background flux variations with respect to the roll-angle for the CHEOPS observation corresponding to epoch 1889, from the light curves reduced by the DRP (top) and PIPE (bottom). The light blue points show individual observations (without uncertainties), and the blue points show data binned over 15° intervals. It is worth noting that the trend of variation is different between the light curves reduced using the DRP and PIPE, since PIPE has a different sensitivity to background stars that contaminate the photometric apertures in the DRP outputs.