47 Tucanae globular cluster. Hubble Space Telescope (HST) image of the 47 Tucanae globular star cluster (NGC 104), one of the brightest clusters in the sky. It is located around 13,400 light years away, in the constellation of Tucana. Globular clusters are old, roughly spherical systems containing hundreds of thousands of closely-packed stars. They formed early on in the history of the universe, around 12 billion years ago. Those within our galaxy lie in its outer spherical halo and contain some of its oldest stars.