Color-magnitude and spatial distributions of stars in tiles b0411 (M54), upper panel, and e0621 (Pismis 2), bottom panel. Left panels: 2D histograms showing all sources in (J − K_s) versus K_s diagram. Middle panels: sources passing color-magnitude selection (0.4 < J − K_s < 1.4, K_s < 17.5) are overlaid in red, with the selection boundaries marked by dashed blue lines. Right panels: spatial distributions in RA versus Dec, where all stars are shown in gray, and color-selected sources are shown in red. Blue crosses mark the cluster centers, and dashed blue circles indicate a 0.3^◦ radius.