NGC 7331 is an unbarred spiral galaxy, about 40 million light years from Earth, that was discovered by William Herschel in 1784. It forms the center piece of a visual collection of galaxies that includes NGC 7335, 7336, 7337 and 7240, all of which lie much further away, at around 300 to 350 million light years. NGC 7331 is similar in size to the Milky Way and has been referred to as the Milky Way's twin. However,  results from NASA’s Spitzer Space Telescope suggest that the Milky Way may be a barred spiral galaxy with only two arms [1, 2].

Unusually, the bulge of NGC 7331 rotates in the opposite direction to the galaxy's disk [3].

Stefan's quintet is a visual quintet, with only four of the galaxies NGC 7317, NGC 7318A, NGC 7318B, and NGC 7319 lying at around 290 million light years away while the fifth, NGC 7320 (the bluish spiral galaxy to the left of the group in the image) is only around 40 million light years from Earth.

The largest image so far taken by NASA's James Webb Space Telescope (a mosaic of over 1000 separate images with a total of 150 million pixels, it is amazing, see [4]) is of the quintet. This shows that, for the four interacting galaxies "Sparkling clusters of millions of young stars and starburst regions of fresh star birth grace the image. Sweeping tails of gas, dust and stars are being pulled from several of the galaxies due to gravitational interactions. Most dramatically, Webb captures huge shock waves as one of the galaxies, NGC 7318B, smashes through the cluster" [4]. Earlier, results from the Spritzer Space Telescope and a telescope in Spain showed that the violent collision involving the four galaxies had created this shock wave, which is larger than the Milky Way [5].

The image was taken on the one brief clear evening that we had in November and it really needs quite a bit more data. I tried a couple of nights ago but the full moon made that a waste of time so I processed what I had. If we get a clear night I'll add more.

The revision is from an Oops. One of the star removals also removed at least two galaxies.  I recombined the stars with a starless image with the full quota of galaxies.

To lose one galaxy, may be regarded as a misfortune; to lose more looks like carelessness.

[1] https://en.wikipedia.org/wiki/NGC_7331#cite_note-6
[2] https://www.universetoday.com/14694/the-milky-way-has-only-two-spiral-arms/#more-14694
[3] https://arxiv.org/abs/astro-ph/9602142
[4] https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-sheds-light-on-galaxy-evolution-black-holes
[5] https://www.spitzer.caltech.edu/image/ssc2006-08a-a-shocking-surprise-in-stephans-quintet