- Messier 73 (M73, also known as NGC 6994) is an asterism of four stars in the constellation Aquarius which was long thought to be a small open cluster. It lies several arcminutes east of globular cluster M72. According to Gaia EDR3, the stars are 1030±9, 1249±10, 2170±22, and 2290±24 light-years from the Sun, with the second being a binary star.