Left: CMD of the sources shown in black in Fig. 6. Sources shown in black are believed to be genuine NGC 6822 sources whilst those sources shown in red have  mag and have therefore been removed from our sample as MW foreground contamination. Right: CMD of the sources with (J − H)₀ > 0.72 mag i.e. mostly belonging to NGC 6822, across the full observed area. The vertical and diagonal sequences relating to the M- and C-type AGB stars, above the TRGB at K₀ ~ 17−17.5 mag, are clearly visible. The horizontal and vertical lines mark the position of the determined TRGB and the colour selection criteria (Sect. 3.3).