... 2000 October 15 . Globular Cluster Omega Centauri . Credit: UIT , NASA . Explanation: Does an old, red globular cluster have any hot, blue stars? The rightmost picture, taken by the Ultraviolet Imaging Telescope in ultraviolet light, shows that indeed it does. Pictured, Omega Centauri is the largest known globular cluster of over 200 in our Galaxy, containing well over a million stars. Many of these stars are evident in the visible light photograph on the left. ... About APOD | ...