(a) Spatial variations of the radiance factor at a phase angle smaller than 1°. (b) Spatial variation of the opposition surge: the ratio of the radiance factor is at a phase angle of 0.5°, and the radiance factor is at a phase angle of 5°. The data were binned into a 2° × 2° longitude-latitude grid. When several values are present for a given bin, the median of the values is considered. The black pixels correspond to regions with no data. The data are projected on the map using the equirectangular projection.