NGC 7331 Galaxy Group and Stephan's Quintet

Also Known as: Caldwell 30 (NGC 7331), Arp 319 (Stephan's Quintet)

Object Type: Unbarred Spiral Galaxy (NGC 7331)

Constellation: Pegasus

Distance from Earth: 39.8 million light years (NGC 7331), 39 million light years (NGC 7331), 210-240 million light years (Stephan's Quintet)

Apparent Magnitude: 10.4

Coordinates: RA 22H 37M 04.1S DEC 34 deg 24 min 56 sec (NCG 7331), RA 22H 35M 57.5S DEC 33 deg 57 min 36 sec

Actual Size: 120,000 light years in diameter (NGC 7331)

Apparent Dimensions: 10.5 arc-minutes x 3.7 arc-minutes (NGC 7331)

Discovered by: NGC 7331 discovered by William Herschel in 1784.
Stephan's Quintet was discovered by Édouard Stephan in 1877 at the Marseille Observatory.

Description: NGC 7331 is the brightest member of the NGC 7331 Group, also known as the Deer Lick Group. The visual grouping is not a real galaxy group because NGC 7331 lies much closer to us than the other galaxies and is not physically associated with them.
The galaxies were nicknamed the Deer Lick Group by amateur astronomer Tom Lorenzin, who observed NGC 7331 and its smaller companions from the Deerlick Gap Overlook in the mountains of North Carolina in the 1980s. The smaller background galaxies are affectionately known as the “fleas.”
The other galaxies lie at distances of 290-370 million light-years and appear much smaller than NGC 7331.
The NGC 7331 Group is catalogued as LGG 459 in the Lyons Groups of Galaxies (LGG) catalogue. Central bulge rotates in the opposite direction to the disk, which is unusual. In spiral galaxies, the bulge typically rotates with the disk.
The other members of the group are the lenticular or unbarred spirals NGC 7335 and 7336, the barred spiral galaxy NGC 7337 and the elliptical galaxy NGC 7340.
These galaxies lie far in the background at distances of approximately 332, 365, 348 and 294 million light years, respectively.
There is a small group of galaxies consists of NGC 7331, NGC 7320, DDO 213 and an anonymous galaxy. The group appears to be projected onto, i.e. in front of Stephans Quintet.
The group also appears to be gravitationally stable. The galaxies in the group are separated by a fair distance on the sky, DDO213 being about 1.7 degrees from NGC 7331. This is because of the relative closeness of the group to us: at a distance of perhaps 45-50 million light years.
Stephan's Quintet is a visual grouping of five galaxies of which four form the first compact galaxy group ever discovered.
The five galaxies that make up Stephan’s Quintet are: elliptical NGC 7317; elliptical NGC 7318A, colliding with barred spiral NGC 7318B; distorted barred spiral NGC 7319; and barred spiral NGC 7320. All are crammed into a tight 20′ area.
The group is the most studied of all the compact galaxy groups. The brightest member of the visual grouping (and the only non-member of the true group) is NGC 7320, which has extensive H II regions, identified as red blobs, where active star formation is occurring. Four of the five galaxies in Stephan's Quintet form a physical association, a true galaxy group, Hickson Compact Group 92, and will likely merge with each other.
Radio observations in the early 1970s revealed a filament of emission between the galaxies in the group. This same region is also detected in the faint glow of ionized atoms seen in the visible part of the spectrum as a green arc.
Stephan's Qunitet was used in the 1946 classic film 'It’s a Wonderful Life' to represent talking angels.

Click Below Image(s) for Full Size:

NGC 7331 group is situated north of the celestial equator and, as such, it is more easily visible from the northern hemisphere.
For visual observers NGC 7331 is a pretty easy target. It should be visible in binoculars from a dark site but a 100mm (4 inch) telescope shows it easily as a dim streak.
As you increase the aperture more detail in the galaxy becomes visible and the companions will also start to appear.

NGC 7331 is best observed in fall or early winter months.

Platesolve

NGC 7331 Galaxy Group

Imaging Details

NGC 7331 Galaxy Group and Stephan's Quintet

Imaging Details
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