Histogram of the flux density of all 217-GHz PCCS2 sources together with vertical lines indicating the flux of the five planets discussed in this paper. It is clear that at 217 GHz, Mars, Saturn, and especially Jupiter, are much brighter than any of the PCCS2 sources. Here the Mars data point corresponds to best estimates for the 22 December 2011 flux density. The majority of the 217-GHz PCCS2 sources have flux densities in the 0.1–1.0 Jy range. Both axes are logarithmic on this figure.