Hα-r vs. Hα colour magnitude diagram for sources in the field of NGC 4302. Red symbols are point sources, black symbols extended sources, while blue symbols show those objects detected in the NB Hα image with ar-band detection of S∕N ≤ 5 (those with Hα-r >−3) or without any counterpart in the r-band (Hα-r = −3). The colour-dependent detection limit of VESTIGE is indicated by the green dashed line. Those sources below the colour magnitude relation, with a colour Hα-r ≤−1 mag (black dotted line) are line emitters and include local galaxies, PNe, and background line ([OIII], [OII], and Lyα) emitting galaxies.