M 13 is probably the best known globular cluster in the northern sky.
These spherical clusters of stars orbit around the center of galaxies
such as the Milky Way, but their orbits are not contained within the
disk where most galactic stars are located; globular clusters are more
like bees swarming around a hive. M 13 is visible to the unaided eye,
under dark skies, near the middle part of the constellation Hercules.
It contains several hundred thousand stars. At its core, the stars are
500 times more closely packed than in our neighborhood of the galaxy; but
collisions between stars are still rare, with an average of a one star per
cubic light year. M 13 lies a little more than 25,000 light years from earth.

2,000 farther away is the spiral galaxy NGC 6207, seen near the left edge of this
image. NGC 6207, and the other numerous galaxies in this image, probably have their
own globular clusters, but M 13 is part of our Milky Way Galaxy.

Image data:
Camera: Canon 350 XT (modified)
Exposure: ISO 800; 2 minutes x 60, 5 minutes x 20
Telescope: 10" Schmidt-Newtonian, Baader MPCC