This constellation pictured is known as Hercules Cluster or M13. This cluster is known to be the best cluster in the northern hemisphere, Hercules Cluster is found in a star pattern called the Keystone, which is located between the two brightest stars Vega and Arcturus. Globular star clusters area huge globe-shaped section filled with hundreds-thousands of stars. Globular clusters are tightly held together by gravity unlike open clusters. Hercules Cluster is best seen with a telescope. Hercules Cluster was named after the famous comet hunter, Charles Messier. Charles first discovered this constellation in 1764. Of the 250 globular clusters in the northern hemisphere, Hercules Cluster is the biggest by far. This cluster is made of gas and dust rich, star-forming spiral galaxies. A blue tint is usually given off by this constellation. 

http://earthsky.org/clusters-nebulae-galaxies/m13-finest-globular-cluster-in-northern-skies