Comparison of the Δ(CduC-Gaia) coordinate differences between Gaia DR2 and EDR3. Panel a) shows the DR2-based Δ(CduC-Gaia) coordinate differences for the sources in sample S4 of the ‘correlation’ method, that is, sources for which the coordinate difference is >0.4″. The EDR3-based coordinate differences of the same stars are shown in panel b). Panel c) shows the DR2- and EDR3-based coordinate differences together, with a line connecting the two coordinate difference of each source. The sample shown in panel c) is a sub-sample of 300 sources out of the sources in panels a) and b). The circle in panels a) and b) has a radius of 0.4″.