Longitude–time diagrams based on subsets of maps such as Fig. 2b. Left panel: latitude bands in the northern hemisphere (25° ≤λ ≤ 40°, see Fig. 2) stacked in time to cover the period from 23 October to 26 December 2020. The far side shows calibrated phase maps, B_Φ, in the range of 20 − 50 G (blue shades). The near side shows the unsigned line-of-sight magnetic field B_los from SDO/HMI (gray shades) in the same range. The unsigned B_los from SO/PHI-FDT for 18 November 2020 is shown in orange. Right panel: same as the left panel but for latitude bands in the southern hemisphere (−30° ≤λ ≤ −15°, see Fig. 2). The red star indicates the occurrence of an M 4.4 class flare near the limb on 29 November 2020, associated with NOAA 12790.