Next is a Globular Cluster named M15. A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite mini-galaxy. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes. M15 is about 33,600 light-years from Earth, and 175 light years in diameter. Within that small area, it has over 100,000 stars! Took this image over 260 minutes at about 75 times magnification.