About C17
Description
NGC 147 is a dwarf spheroidal galaxy in Cassiopeia, about 2.5 million light-years away. It is a satellite of the Andromeda Galaxy (M31) and forms a pair with its neighbor NGC 185 (C18). The galaxy has virtually no gas, dust, or recent star formation.
Observing Tips
A faint, diffuse smudge requiring at least a 6-inch telescope and dark skies. It has very low surface brightness. Use low power and averted vision. Located about 1 degree from NGC 185 and both can be seen in the same wide field. Best in autumn.
History
Discovered by John Herschel in 1829. It was one of the first dwarf galaxies recognized as a satellite of M31, helping astronomers understand the hierarchical structure of galaxy groups.
Fun Facts
NGC 147 stopped forming stars about 3 billion years ago, making it a "dead" galaxy. Despite being a satellite of Andromeda, it lies about 660,000 light-years from M31's center.
Observe
1Properties
Position & Identifiers
2How easy to spot?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Easy | Easy | 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
Blueshift
10
Size Comparator
Discover
11
Light Travel Time Machine
12
Relativistic Travel
Community Photos (1)
Credit: NASA Hubble Space Telescope. License: CC BY 2.0. (Wikimedia Commons)
Skybred Mar 2, 2026
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
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