Accuracy of the photometric calibration: For the different combinations of filters and nights used to calibrate the data sets discussed in this work and Paper I, the scatter Δm′ around the best-fit solution (solid line) is shown. Each point corresponds to an SDSS standard source for which the abscissae give the separation θ₀ in arc minutes from the centre of the pointing. Note that for each panel a maximum Δm′ has been determined by iterative 3σ-clipping.