Differential parallax bias estimated by means of RC stars. The points show the locations of the ridges in Fig. C.2 for area N (filled red circles) and S (open blue squares). The curves show the expected locations at G = 17 according toTable 6 for area N (solid red) and S (long-dashed blue), assuming that the curvature with colour (j = 2) is the same in both areas. If the curvature had flipped sign with β, the ridge location for area N should instead follow the up-bending, short-dashed black curve.