NGC 7331 shines at 9.5mag in the constellation of Pegasus at a distance of 47 million light-years. With an aparent size of nearly 10', its true diameter measures about 130'000 light-years, which is about the same size as the great Andromeda galaxy M31, bigger then out Milky Way.
Only about 1/2° south-west, a group of five smaller galaxies can be found, the Stephan's Quintet, also known as Hickson 92 or Arp 319. NGC 7320, the bluish member of this group, seems to be related to NGC 7331, while the other four galaxies are recendig at the same speed and are therefore assumed to be gravitationally bound to each other.
[from O'Meara]
Date: 10/02/2011
Size:
Image Data
Telescope: RCOS 14.5" f/8
Mount: ASA DDM85
Detector: Apogee U16M
Filters: Astrodon Gen 2
Exposures: LRGB 460:160:160:160 min ( 20 min subs)
