Top left: reduced WHT V-band mosaic of the Perseus cluster core. The x- and y-axes correspond to R.A. and decl., respectively. The black circle marks NGC 1275. Top right: partly object-subtracted mosaic with overlaid mask indicating the excluded inner regions of extended high surface brightness sources. Bottom: mosaic with subtracted SEXTRACTOR background map (BACK_SIZE = 64 pixels) and the high surface brightness object mask used for source detection. The gray-scale bar indicates the surface brightness in mag arcsec⁻². North is up, and east is to the left.