CMDs of star-like objects in the studied field. An isochrone of 7 Gyr age and Z = 0.0001 metallicity (the blue line) is plotted in all panels. Additionally, we plot a) photometric AST star scatter limits (based on Fig. 2c and d), shown by cyan and red lines, as well as the lower limit of the MW foreground star distribution derived from the Besançon models, shown with the grey dashed line; b) isochrones of 5 and 10 Gyr (Z = 0.0001) shown with cyan and red lines, respectively; and c) an isochrone of 7 Gyr and Z = 0.0006 shown with the red line.