M92 Globular Cluster

M92 is in the constellation Hercules, like its more spectacular neighbour M13. It is a very fine globular cluster in its own right, despite its proximity to M13. In absolute terms it is one of the brightest of the globular clusters surrounding our Milky Way galaxy, but, being about 26700 light-years away from us it appears pretty faint, being just visible to the naked eye under good conditions. 

It contains something like 200000 stars and has a diameter of about 17 light-years (to the circle enclosing half the brightness). Based on spectral analysis (which shows a high abundance of the "primitive" elements hydrogen and helium) it has been estimated that the age of this cluster is about the same as the age of the universe itself, which is quite remarkable.

Where it is in the sky:

In the summer and early autumn skies, it's easy to find the "keystone" shape in the central part of the constellation Hercules, not far from the bright star Vega. M92 is a bit to the north of this shape. It is just visible to the naked eye, from a dark site.