Galaxies Galore – Stephan’s Quintet and NGC 7331/C30
Stephan’s Quintet is to the left, consisting of 4 related galaxies and NGC 7320 which is a foreground galaxy. Their brightness’s range from +14.6 to +15.7. NGC 7318B is colliding with gas in the group, producing a huge shock wave bigger than the Milky Way, spreading through the medium between the galaxies, heating the gas to millions of degrees, emitting X-rays. A sixth galaxy, NGC 7320C appears to be connected by a tidal tail (just visible) to NGC 7319.
NGC 7331 or Caldwell 30 (to the right) is similar in size and structure to the Milky Way, 40M light years away. A discovery by William Herschel in 1784. It is the main body in the NGC 7331 Group, which contains unbarred spirals NGC 7335 and 7336, the barred spiral galaxy NGC 7337 and the elliptical galaxy NGC 7340. These other galaxies are all much further away (~300M ly), so not related to NGC 7331.