A favourite of amateurs and professionals alike, M13 sits for Hubble portrait

The globular cluster M13 in Hercules is a favorite target for amateur astronomers and professionals alike, a vast concentration of stars easily visible in binoculars and even to the unaided eye on clear, dark nights. But through a telescope, M13 turns into a glimmering metropolis of more than 100,000 suns, one of the brightest and best-known globular clusters in the northern sky. Now rising in the early evening sky for viewers in the northern hemisphere, M13 offers an especially beautiful sight when imaged by the Hubble Space Telescope. This view is a composite of archival data collected in 1999, 2000, 2005 and 2006 with the Wide Field Planetary Camera 2 and the Advanced Camera for Surveys.

M13, the great globular cluster in Hercules. Click the image for expanded views. Image: NASA, ESA and the Hubble Heritage Team (STScI/AURA); Acknowledgment: C. Bailyn (Yale University), W. Lewin (Massachusetts Institute of Technology), A. Sarajedini (University of Florida), and W. van Altena (Yale University)