47 Tucanae

47 Tucanae (47 Tuc or NGC 104) is the second brightest globular cluster in the sky, with an angular size roughly the same as that of the Sun or Moon, with an age of 13 gigayears and a low metallicity. It shows hints of more than one sub-population. It has more than a million stars and has a very dense core. Its radius is about 60 ly. It is an obvious candidate for the study of globular clusters and is the subject of searches for a central black hole and for extra-solar planets.