Stephan's Quintet is a visual grouping of five galaxies of which four form the first compact galaxy group ever discovered. The group, visible in the constellation Pegasus, was discovered by Édouard Stephan in 1877 at the Marseille Observatory. The group is the most studied of all the compact galaxy groups. The brightest member of the visual grouping is NGC 7320, which has extensive H II regions, identified as red blobs, where active star formation is occurring.
NGC 7320 is a spiral galaxy in Stephan's Quintet. However, it is not an actual member of the galaxy group, but a much closer line-of-sight galaxy at a distance of about 40 million light years, the same as the nearby NGC 7331. Other galaxies of Stephan's Quintet are some 300 million light-years distant.
Robert's Quartet is a compact galaxy group approximately 160 million light-years away in the constellation Phoenix. It is a family of four very different galaxies whose proximity to each other has caused the creation of about 200 star-forming regions and pulled out a stream of gas and dust 100,000 light years long. Its members are NGC 87, NGC 88, NGC 89 and NGC 92, discovered by John Herschel on the 30 September 1834.
NGC 5921 is a barred spiral galaxy located approximately 65 million light-years from the Solar System in the constellation Serpens Caput. It was discovered by William Herschel on 1 May 1786. In February 2001 a type II supernova was discovered in NGC 5921. It is a member of the Virgo III Groups, a series of galaxies and galaxy clusters strung out to the east of the Virgo Supercluster of galaxies.
NGC 7318 is a pair of colliding galaxies about 280 million light-years from Earth. They appear in the Constellation Pegasus and are members of Stephan's Quintet.
NGC 6027 is a lenticular galaxy discovered by Édouard Stephan in 1882 that is the brightest member of Seyfert's Sextet, a compact group of galaxies.
NGC 6027a is a spiral galaxy that is part of Seyfert's Sextet, a compact group of galaxies, which is located in the constellation Serpens. In optical wavelengths, it has a strong resemblance to Messier 104, the Sombrero Galaxy, with which it shares a near equivalent orientation to observers on Earth.
NGC 6027b is an interacting lenticular galaxy that is part of Seyfert's Sextet, a compact group of galaxies currently in the process of colliding and merging, which is located in the constellation Serpens.
NGC 6027c is a barred spiral galaxy that is part of Seyfert's Sextet, a compact group of galaxies, which is located in the constellation Serpens.
NGC 6027d is a barred spiral galaxy that is strictly a visual member of Seyfert's Sextet, a compact group of galaxies, which is located in the constellation Serpens. NGC 6027d is not interacting with the other galaxies in the cluster, but is in the background and just happens to be in the same line of sight. The galaxy is nearly 700 million light years away from the interacting group and is believed to be extremely large in size.
NGC 6027e is a tidal tail of NGC 6027, not an individual galaxy, that is part of Seyfert's Sextet, a compact group of galaxies, which is located in the constellation Serpens.
NGC 7331 Group is a visual grouping of galaxies in the constellation Pegasus. Spiral galaxy NGC 7331 is a foreground galaxy in the same field as the collection, which is also called the Deer Lick Group. It contains four other members, affectionately referred to as the "fleas": the lenticular or unbarred spirals NGC 7335 and NGC 7336, the barred spiral galaxy NGC 7337 and the elliptical galaxy NGC 7340. These galaxies lie at distances of approximately 332, 365, 348 and 294 million light years, respectively. Although adjacent on the sky, this collection is not a galaxy group, as NGC 7331 itself is not gravitationally associated with the far more distant "fleas"; indeed, even they are separated by far more than the normal distances of a galaxy group.
NGC 3718, also called Arp 214, is a galaxy located approximately 52 million light years from Earth in the constellation Ursa Major. It is either a lenticular or spiral galaxy.
NGC 218, also known as UGC 480, is a spiral galaxy located approximately 500 million light-years from the Sun in the constellation Andromeda. It was discovered on October 17, 1876 by Édouard Stephan, and is interacting with the galaxy PGC 2726.
LEDA 83677 is a lenticular galaxy located about 290 million light-years away in the constellation Coma Berenices. It is a member of the Coma cluster of galaxies. LEDA 83677 is also classified as a type 1 Seyfert galaxy. The core of the galaxy is emitting high-energy X-rays and ultraviolet light, probably caused by a massive black hole lurking in the core.
NGC 1019 is a barred spiral galaxy approximately 316 million light-years away from Earth in the constellation of Cetus. It was discovered by French astronomer Édouard Stephan on December 1, 1880 with the 31" reflecting telescope at the Marseille Observatory.
NGC 1199 is an elliptical galaxy approximately 107 million light-years away from Earth in the constellation of Eridanus. It was discovered by William Herschel on December 30, 1785.
NGC 2936 is an interacting spiral galaxy located at a distance of 326 million light years, in the constellation Hydra. NGC 2936 is interacting with elliptical galaxy NGC 2937, located just beneath it. They were both discovered by Albert Marth on Mar 3, 1864. To some astronomers, the galaxy looks like a penguin or a porpoise. NGC 2936, NGC 2937, and PGC 1237172 are included in the Atlas of Peculiar Galaxies as Arp 142 in the category "Galaxy triplet".
NGC 5910 is an elliptical galaxy located about 540 million light-years away in the constellation Serpens. It was discovered by astronomer William Hershel on April 13, 1785. NGC 5910 is also a strong radio source with a conspicuous nuclear jet.
NGC 5940 is a barred spiral galaxy located in the Serpens constellation. The galaxy was found on April 19, 1887, by Lewis Swift, an American astronomer. NGC 5940 is located 500 million light-years away from the Milky Way and it is approximately 140,000 light-years across in diameter.
