APOD 2.4

Located in Hercules, M13, the Great Globular Cluster contains hundreds of thousands of stars, and is one of the brightest globular star clusters in the northern sky. At approximately 25,000 light-years, the stars squeeze into a region about 150 light-years in diameter, but in the cluster core over 100 stars would fit into a cube only 3 light-years on a side. Which is very close, as the closest star to the Sun is about 4 light-years away. This picture of M13 includes recent telescopic images of the dense core and "digitized photographic plates" taken between 1987 and 1991 using the Samuel Oschin Telescope at the Palomar Observatory. This picture shows both the inner and outer areas of the star cluster in great detail. Also, to the upper left of M13, NGC 6207, a distant galaxy, is also visible. To think of the millions of stars located in this relatively small area of space is incredible. There are so many packed into such a small area. It's also pretty cool to see M13 in Hercules, since it is one of the many constellations we have learned about.