CMD of UMi members (RGB, HB, and RR Lyrae stars) using the same symbols and colour-coding as in Fig. 19. Overlaid on the CMD are Padua stellar isochrones (Bressan et al. 2012) for a fixed age, t = 13 Gyr, and three different metal abundances (Z = 0.0003 grey, Z = 0.0004 purple, and Z = 0.0005 lime). Isochrones are fixed at a distance d = 45 kpc in the left panel and at d = 40 kpc in the right panel. The pink circles highlight 43 variable stars brighter than G =19.25 mag discussed in Sect. 4, among which are ten ACs of UMi.