Illustration the Grad-CAM function that helps identifying the regions of interest in the image that triggered the O’TRAIN classification. Left: residual cutout (32 × 32 pixels) of a bogus identified in the JAST telescope images. Center: the GRAD-CAM Heatmap (8 × 8 pixels) showing the final feature maps × their importance where our O’TRAIN CNN focused on to take its decision. Right: rescaled Grad-CAM heat map (32 × 32 pixels) for a direct comparison with the cutout.