C13 · Owl Cluster
| Chinese name | 猫头鹰星团 |
|---|---|
| Type | Open cluster |
| Constellation | Cas |
| RA | 01h19m |
| Dec | +58° |
| Apparent magnitude | 6.4ᵐ |
| Hemisphere | Northern |
| Best season | Autumn |
| Difficulty | Moderate |
| Focal length | 中焦 400–800mm |
About
The Owl Cluster (NGC 457, also called the Alien or ET Cluster) lies about 7,900 light-years away in Cassiopeia, a bright and whimsical open cluster. Two prominent stars form a pair of eyes, while trailing star chains look like outstretched arms, giving it the look of an owl or a wide-armed alien. The brightest 'eye,' the yellow supergiant Phi Cassiopeiae, may not actually be a true cluster member. The cluster holds a few dozen stars and is about 21 million years old. Bright and characterful, it is a crowd-pleasing autumn target in Cassiopeia for both imaging and visual observing.