About NGC 7331
Description
NGC 7331 is a bright spiral galaxy in Pegasus, about 40 million light-years away. Often called the Milky Way's twin, it is a large, inclined spiral with a prominent bulge and well-defined dust lanes. It appears to lead a small group of background galaxies known as the Deer Lick Group.
Observing Tips
One of the brighter non-Messier galaxies, visible in a 4-inch telescope as an elongated glow with a bright core. An 8-inch scope shows the disk and hints of dust lanes. The four smaller background galaxies require 10 inches or more. Best in autumn.
History
Discovered by William Herschel on September 5, 1784. The group of background galaxies (NGC 7335, 7336, 7337, 7340) was once thought to be physically associated but lies 10 times more distant.
Fun Facts
NGC 7331 rotates in the opposite direction from what its spiral arm winding would suggest, a phenomenon called "backwards spinning" that remains unexplained.
Observe
1Properties
Position & Identifiers
2How easy to spot?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Easy | Medium+ | Medium |
| 150 mm Newton 150mm Newt. | Easy | Easy | Easy |
| Celestron C8 (203 mm SCT) C8 203mm | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
3Visibility
Set a location in User Settings to see visibility data.
4
Eyepiece View
5
Best Magnification
Explore
6
Surface Brightness
7
Morphology Decoder
8
Inclination & True Shape
9
Redshift
10
Size Comparator
Discover
11
Light Travel Time Machine
12
Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
Explore Nightbase
Related knowledge, tools, and stories — no observation planning required.
