Core of the Globular Cluster NGC 6624
This is a comparison of pictures of the core of the globular cluster NGC 6624, as imaged with the European Space Agency's Faint Object Camera aboard NASA's Hubble Space Telescope. This comparison image demonstrates that Hubble's high resolution and ultraviolet sensitivity allow astronomers to pick out the faint blue counterpart to an X-ray burster buried in the globular cluster. (An X-ray burster is a class of unusual double star that is a source of violent bursts of X-rays.) HST clearly distinguishes the star from others crammed together in the dense core of the cluster.