The famous globular cluster Messier 13 (NGC 6205) in Hercules, seen in a blue-light image taken with the Lowell Observatory 1.1-meter telescope. The nonlinear intensity mapping simultaneously shows stars with a wide brightness range, from the brightest red giants down to the main sequence.
For a wider view, here's a 10-minute red-light exposure taken with the UA 16-inch telescope. This spans a 17-arcminute field, giving a better impression of the large extent of the cluster.
Last changes: 4/2001 © 2001