Beginning with Pyramids of Mars, the Doctor often refers to Gallifrey being in the constellation of Kasterborous. Since constellations are arbitrary divisions of stars in a planet's sky, this only makes sense if Kasterborous is a constellation in a particular sky. Bearing in mind the Doctor's familiarity with it, Earth's would seem a sensible suggestion, especially since in Mission to the Unknown Earth SSS agent Marc Cory also refers to an oddly-named constellation.
Therefore, we can assume that, at some point between 1995 and 3999, the constellations of Earth are renamed. They include Kasterborous, Mir (Mission to the Unknown), Canthares (Image of the Fendahl), Skytha (The Ribos Operation) and Cetes (possibly Cetus, Vengeance on Varos).