Bottom: distribution of the residuals in μK_CMB, computed using Eq. (9), for detector 143-1a, plotted versus observation date and satellite rotation phase. Top: expected pattern for the solar dipole, in μK_CMB. Comparison of the two plots provides a check of the level of residual gain variation after applying the bogopix gains. In the residuals the sharp features (dark blue) correspond to the Galaxy observations, where band-pass effects have not been corrected.