Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars.
Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky as seen from the center of mass of the Solar System compared to the abstract background of the more distant stars