Wikipedia:WikiProject Geographical coordinates/globe:

The  parameter specifies the planet, dwarf planet, asteroid, or natural satellite upon which the coordinates reside. Apart from earth (the default), recognized values are: mercury, venus, moon, mars, phobos, deimos, ceres, vesta, jupiter, ganymede, callisto, io, europa, mimas, enceladus, tethys, dione, rhea, titan, hyperion, iapetus, phoebe, miranda, ariel, umbriel, titania, oberon, triton, pluto, and charon.

Very rough mapping is provided on geohack for almost all supported globes. The pop-out WikiMiniAtlas system provides limited mapping for Moon, Mars, Mercury, Venus, Io, and Titan,.

The maps roughly implies a coordinate reference system, but does not clearly specify one (unlike Earth's WGS84). Since the template defaults to east longitude, the  direction must be specified for globes that measure longitude westward. For celestial coordinates, use Sky instead.