Size‐magnitude diagram for VCC 798 with 90% completeness curves for different galaxy surface brightnesses. This plot is the same as the bottom left of Fig. 1, except that we have now overplotted our 90% completeness curves for underlying galaxy surface brightnesses of ﹩\mu _{z,\mathrm{galaxy}\,}=18﹩, 19, 20, 21, and 22 mag arcsec⁻² as labeled. Notice that at ﹩\mu _{z,\mathrm{galaxy}\,}=19﹩, most of the diffuse clusters become difficult to detect. In Fig. 13 we show where this isophotal surface brightness level lies in the galaxy.