Deer Lick Group and Stephan's Quintet

More than 15 galaxies are visible in this image (see annotated version below).

On the left side of the image is a group of galaxies named the Deer Lick Group (reportedly, an amateur astronomer gave the name to the group in honor of Deer Lick Gap in the mountains of North Carolina where he observed and once had an especially fine view of this group of galaxies). The most prominent member is NGC 7331, at a distance of 46 million light years. NGC 7331 was discovered by William Herschel, and was one of the brightest galaxies overlooked by Messier in his catalog. Its structure is remarkably similar to our own galaxy, the Milky Way, including its mass, spiral structure, star distribution, and central black hole. The other smaller galaxies in the “group” are probably 10 times more distant.

Stephan's Quintet

In the right upper portion of the image is a tight grouping of galaxies called Stephan’s quintet (discovered by Eduoard Stephanis in 1877 at Marseilles Observatory). It is the first compact galaxy group ever discovered and the most studied of all compact galaxy groups. The brightest galaxy NGC 7320, at the lower right of the group and displaying a bluish hue, was subsequently found to have a much smaller redshift than the others, indicating that is an “interloper”, a superimposed foreground galaxy at a distance of 60 million light years (the premise of the method lies in the "Hubble Law" which states that due to the general expansion of the universe, the velocity at which a galaxy is receding is proportional to the distance of that galaxy from us. Galaxies having the same redshift are thought to reside at the same distance from earth.) The other 4 in the tight group (called Hickson Compact Group 92) are at a distance of 300 million light years, and are physically associated in a cosmic dance that most likely will end with the galaxies merging. These include the elliptical galaxy NGC 7317, two converging galaxies (NGC 7318), and seen at the lower left of the group NGC 7319, another spiral galaxy whose arms are being distorted by the gravitational interaction with the other galaxies. Below and slightly to the left of the group is a faint barred spiral galaxy, NGC 7320C, which is now considered to be an outlying member of the galaxy group.

(The above information obtained from several sources including "The 100 Best Astrophotography Targets" by Ruben Kier).

Annotated Version:

Constellation: Pegasus