Globular cluster M13. Hubble Space Telescope (HST) image of hundreds of thousands of stars making up the globular cluster M13. This is one of the brightest and best-known globular clusters in the northern sky. M13 is located in the constellation of Hercules and is around 25,000 light years from Earth. The area seen here is around 36 light years across. This image is a composite of observations made in 1999, 2000, 2005 and 2006, using the HST's Wide Field Planetary Camera 2 (WFPC2) and the Advanced Camera for Surveys (ACS).