g − r_U versus r_I − i diagram for the Galactic longitude range, 60° < ℓ < 65°. As in Fig. 8 the density of sources is portrayed by the square root contoured colours, with yellow representing the lowest density of four sources per 0.02 × 0.02 mag² bin. The peak density traced by the darkest colour is over 5000 per bin. Only sources with r_I <  19 mag and errBits = 0 were used. The solid line in red is the unreddened main sequence, while the dashed line is the reddening line for an A2V star up to A_V = 10.