Everything here is computed or sourced. Star positions come from the HYG catalogue and precess properly over the whole range of the clock; the planets and our Moon come from an ephemeris; the surface maps are spacecraft photographs from NASA and USGS.

Where something is not known, it says so. A moon whose orbit was fitted rather than computed tells you how far out it can be. A hemisphere no spacecraft has photographed is left flat rather than painted in, and named. A sky culture's names that nobody has checked with a speaker are marked unchecked. An empty sky always explains which of the five possible reasons it is empty for.