NGC 7331 and Stephan’s Quintet

The largest galaxy in this image is spiral NGC 7331, lying about 40 million light years away in the direction of Pegasus.

Over to the left can be seen the five galaxies making up Stephan’s quintet (the centre two are very close together and share the same NGC number – 7318). This was the first compact galaxy group discovered, in 1877. The uppermost of the five in this image, NGC 7320, is at about the same distance as NGC 7331, but the other four members of the quintet, a gravitationally-interacting group, lie at a distance of 200-300 million light years. Faint trails of luminosity can be made out where the galaxies have pulled matter from each other during their interactions.

There are several faint galaxies to the upper right of 7331, the brightest of which are NGC 7335 and 7337 (both mag 14).  Together they are known as the Deer Lick group or, less formally, the Fleas.