The brightest globular cluster in the northern
latitudes, M13 shines at magnitude 5 and is visible to the naked eye from a
dark sky site. It is approximately 10' in diameter with around 300,000 stars.
It is located in western edge of the Keystone in the constellation of Hercules.
It takes an 11-12" telescope to resolve the stars, like diamond dust on black
velvet. This great cluster of stars lies 25,000 light years from earth. This is
roughly one quarter the width of our Milky Way Galaxy. The larger galaxy, upper
right-hand corner is NGC 6207 at magnitude 12.2. The smaller galaxy, just to
the upper right of the globular cluster, is IC 4617 magnitude