The heart of Messier 13, the Great Hercules Cluster, sparkles in this recent Hubble Space Telescope image. In 1779, William Herschel described it as ‘a most beautiful cluster of stars.’ The cluster, which is at least 12 billion years old, contains hundreds of thousands of stars packed into a tight ball. It is 25,000 light-years away. To see it, look in the east-northeast in early evening for the Keystone of Hercules, which looks like a lopsided ‘square’ of stars. M13 is between the two stars at the top of that pattern, a bit closer to the one on the left. [ESA/NASA]
Find out more in our radio program entitled Hercules Cluster.