|Observation data (J2000.0 epoch)|
|Right ascension||01h 19m 32.6s|
|Declination||+58° 17′ 27″|
|Distance||7.922 kly (2.429 kpc)|
|Apparent magnitude (V)||6.4|
|Apparent dimensions (V)||13.0′|
|Other designations||Owl Cluster, E.T. Cluster, Caldwell 13, Cr 12, Mel 7, OCL 321, Lund 43, H VII-42, h 97, GC 256,|
NGC 457 (also designated Caldwell 13, and known as the Owl Cluster, E.T. Cluster, Dragonfly Cluster, or Kachina Doll Cluster) is an open star cluster in the constellation Cassiopeia. It was discovered by William Herschel in 1787, and lies over 7,900 light years away from the Sun. It has an estimated age of 21 million years. The cluster is sometimes referred by amateur astronomers as the Owl Cluster, the E.T. Cluster (due to its resemblance to the movie character) or the "Skiing Cluster". Two bright stars Phi Cassiopeiae (magnitude 5) and HD 7902 (magnitude 7) can be imagined as eyes. The next brightest star is the red supergiant variable star V466 Cassiopeiae. The cluster features a rich field of about 150 stars of magnitudes 9-13.
- Frinchaboy, Peter M.; et al. (2008). "Open Clusters as Galactic Disk Tracers. I. Project Motivation, Cluster Membership, and Bulk Three-Dimensional Kinematics". The Astronomical Journal. 136 (1): 118–145. arXiv:0804.4630. Bibcode:2008AJ....136..118F. doi:10.1088/0004-6256/136/1/118. See table I, p. 12.
- "The Owl Cluster (Open Cluster)". Retrieved 2020-10-28.
- "NGC 457". Astronomy Magazine. Retrieved 2020-10-13.