... APOD: 2008 April 2- Globular Cluster M55 from CFHT . ... The fifty-fifth entry in Charles Messier's catalog, M55 is a large and lovely globular cluster of around 100,000 stars. Only 20,000 light-years away in the constellation Sagittarius, M55 appears to earth-bound observers to be nearly 2/3 the size of the full moon. ... Two years ago, images from the robotic Cassini spacecraft orbiting Saturn led astronomers to the undeniable.. ... Spiral Galaxy NGC 2841 . ... Saturn and Titan from Cassini . ...