... Tonight's Sky . ... Star Atlas . ... Hubble watches starsт?? clockwork motion in nearby galaxy . ... Hubble recorded the stars' slight movements during a seven-year period. ... Hubble's precision tracking offers a new way to determine a galaxy's rotation by the "sideways" proper motion of its stars, as seen in the plane of the sky. ... By using Hubble to study the stars' motions over several years, we can actually, for the first time, see a galaxy rotate in the plane of the sky," said van der Marel....