NGC 7331

NGC 7331 and Stephans quintet (NGC 7317 NGC 7318a NGC 7318b NGC 7319 and NGC 7320c)


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Technical details:

Location / Date: Outside of Ramnäs, Västmanland, Sweden / 2015-October

Optics: Orion Optics UK AG12

Mount: 10 Micron GM1000 HPS (Unguided)

Camera: Canon EOS 100D (Modded with Baader ACF filter)

Exposure: 40 x 240 seconds on ISO 3200 + 34 x 90 seconds shot on ISO1600 (cumulative exposure time is 3 hours and 31 minutes)

Processing: Pixinsight and Photoshop


Image details:

NGC 7331 (also known as Caldwell 30) is a spiral galaxy about 40 milion light-years (12 Mpc) away from the Earth in the constellation Pegasus. NGC 7331 is the largest galaxy which is seen in the right upper quadrant of my image above. It was discovered by William Herschel in 1784. NGC 7331 is the brightest member of the NGC 7331 Group of galaxies. The galaxy is similar in size and structure to the galaxy we inhabit, and is often referred to as "the Milky Way's twin", although recent discoveries regarding the structure of the Milky Way may call this similarity into doubt.

The NGC 7331 Group is a group of galaxies in constellation Pegasus. NGC 7331 spiral galaxy is the brightest member of the group. This group is also called the Deer Lick Group.

Stephan's Quintet which are seen in the left lower quadrant of my image above, is a visual grouping of five galaxies of which four form the first compact galaxy group ever discovered. The group was discovered by Édouard Stephan in 1877 at Marseille Observatory. The group is the most studied of all the compact galaxy groups. This galaxy group is located about 280 million light years from Earth. The brightest member of the visual grouping is NGC 7320. These galaxies are of interest because of their violent collisions. Four of the five galaxies in Stephan's Quintet form a physical association, called Hickson Compact Group 92, and are involved in a cosmic dance that most likely will end with the galaxies merging. (Information from Wikipedia)