Difference between the 30 GHz LFI map calibrated using the OSG calibration (Sect. 3.1) and the nominal 30 GHz map (calibrated using the 4 K method, see Sect. 3.2). The residual dipole visible in the map is due only to the latter calibration, as the nominal method removes any residual dipole. A few stripes are visible as well: they are caused by Galactic straylight affecting the fit with the dipole (OSG calibration), as hinted by the fact that such stripes are positive.