Messier 0 ()
Messier object number 0 (NGC 6397) is a globular star cluster and in the constellation of Altar. It is also known as the . It is approximately 7,800 lightyears away from earth.
This globular cluster in the constellation of Altar contains around 400.000 stars. It is approximately 8,200 lightyears away from earth, which makes it one of the closest globular clusters. It has undergone a core collapse, which means that the center of the cluster has contracted into a very dense stellar agglomeration. White dwarfs, neutron stars, and black holes are likely to be at the center of the cluster.