Galaxy Group Hickson 90 (HCG90), located just above the center of this image, is a small group of galaxies located in the constellation Piscis Austrinus, approximately 160 million light-years away from Earth. It is named after astronomer Paul Hickson, who compiled a catalog of compact groups of galaxies in the early '80s. HCG 90 consists of four major galaxies, NGC 7172, NGC 7173, NGC 7174, and NGC 7176, as well as a number of smaller galaxies and intergalactic gas. NGC 7173 and NGC 7176 appear to be smooth, normal elliptical galaxies without much gas and dust. In stark contrast, NGC 7174 is a mangled spiral galaxy, barely clinging to independent existence as it is ripped apart by its close neighbours. NGC7172 is an intriguing edge-on spiral galaxy showing a prominent lane of dust running across its length and is a so called Seyfert galaxy, a type of galaxy which intensely luminous nucleus is powered by matter accreting onto a supermassive black hole.

Well documented in this long exposure are the group complex and interacting structures, including faint tidal tails, bridges, and shells, suggestion of the significant gravitational interactions and mergers the galaxies have undergone in the past. These strong tidal interaction surging through the galaxies has dragged a significant number of stars away from their home galaxies. These stars are now spread out, forming a tenuous luminous component in the galaxy group. The extension of these structures is visible in this image stretching well over half degree, the apparent size of the full Moon, which has seldom if ever been so clearly documented in a color image before. Studies of HCG 90 have yielded valuable insights into the dynamics of small galaxy groups and the effects of gravitational interactions on galaxy evolution. In particular, the group's complex morphology and relatively low velocity dispersion suggest that it is in the process of forming a compact group, which could eventually evolve into a single, massive galaxy.

The "bright" blue star anchoring the center of this frame (HD209253) is in reality just beyond the visibility of unaided eyes. At the bottom of the image lays NGC 7187, a lenticular galaxy possessing a bright circular inner ring and a faint elongated outer ring and lacks prominent spiral arms. NGC 7187 is known to have a significant population of globular clusters, which are densely packed groups of stars that orbit the galaxy.

Dozen of other galaxies of many different sizes, shapes and colors also populate this ramarkably rich cosmic canvas.

Takahashi CCA250 (250/f5) - ZWO 6200MM - L (760m) R (90m) G (90m) B (110m) - AMT Observatory (A.Lau/M.Lorenzi/T.Tse), Río Hurtado, Chile. Image processing M.Lorenzi.