M31 Globular Clusters in the Hubble Space Telescope Archive. I. Cluster Detection and Completeness, Barmby, Pauline,Huchra, John P., The Astronomical Journal, 122, 2001-11-01 00:00:00, 2001AJ....122.2458B||M31 Globular Clusters in the Hubble Space Telescope Archive. II. Structural Parameters, Barmby, Pauline,Holland, Stephen,Huchra, John P., The Astronomical Journal, 123, 2002-04-01 00:00:00, 2002AJ....123.1937B
Launched in 1990, the NASA/ESA Hubble Space Telescope remains the premier UV and visible light telescope in orbit. With well over 1.6 million observations from 10 different scientific instruments, the ESA Hubble Science Archive is a treasure trove of astronomical data to be exploited.