Ecliptic scan-angle distribution for the nominal scanning law during the Gaia DR3 time range. For a certain ecliptic latitude (horizontal slice), the colour represents the occupancy percentage per 1° scan-angle bin (summing up to 100% over all scan angles) to highlight non-uniformities in the scan-angle distribution at different ecliptic latitudes. Top panel: distribution for sources along a half-circle slice at ecliptic longitude λ = 90°. Bottom panel: same as top panel, but for an all-sky uniform HEALPix grid of sources (that is, all ecliptic longitudes for a given latitude). The strong imbalance of scan angles for sources |β|≤45° has a strong impact on the propagation strength of certain scan-angle-dependent signals; see text for details.