Coordinate differences between CduC and Gaia EDR3 as a function of Gaia G_BP magnitude, for the single-exposure plates. Panel a) is for RA and panel b) is for Dec. The normed histogram of the logarithm of the number of stars within the magnitude bins is shown as a solid white curve, and the completeness magnitude limit of the CduC survey is shown as a vertical solid white line. The normed cumulative number of stars is shown as a dashed white line, and the 99% magnitude limit is shown as a vertical dashed white line.