Robert’s Quartet is four different galaxies in the process of colliding and merging. The galaxies reside in the Phoenix constellation approximately 160 million light-years away. Its members are NGC 87, NGC 88, NGC 89 and NGC 92, discovered by John Herschel in the 1830s.
The quartet is one of the best examples of compact groups of galaxies. Since such groups contain four to eight galaxies in a very small area, they provide great laboratories for the study of galactic interactions and their effects. They are particularly good to study the formation of stars. The brightest member of the group has a magnitude of 14, while the quartet as a whole has a total visual magnitude of almost 13.
The galaxies, at about 76,000 light years, are all within a circle of radius of 1.6 arcmin. It was named by Halton Arp and Barry F. Madore, who compiled A Catalogue of Southern Peculiar Galaxies and Associations in 1987.