The second-brightest globular cluster in the sky, appearing of 4th magnitude and the same diameter as the Moon, lying about 15 000 l.y. away in the constellation Tucana. It is also known as NGC 104. Its true diameter is about 150 l.y., and its mass about 106 solar masses. The density of stars at its centre (about 1000 stars per cubic light year) makes it one of the densest stellar environments known.