101 Must-See Cosmic Objects: Seyfert’s Sextet

Located in Serpens Caput, a constellation with few deep-sky objects, Seyfert’s Sextet was one of the first compact galaxy groups ever noted. That occurred in 1948, when astronomer Carl Seyfert discovered that the previously cataloged NGC 6027 was actually more than one object. His Sextet became the densest group of galaxies known at the time.

Seyfert’s initial observation described six galaxies close together, but that isn’t the case. Later observations revealed only four int