Berkeley 21
Number of stars per data source
Reference 88 : 769 stars
Reference 191 : 1567 stars
References
- 88
- Phelps R.L., Janes K.A., Montgomery K.A.
- (1994) Astron. J. 107, 1079
- Development of the galactic disk: a search for the oldest open clusters
- 1994AJ....107.1079P
- 191
- Tosi M., Pulone L., Marconi G., Bragaglia A.
- (1998) Mon. Not. R. Astron. Soc. 299, 834
- Old open clusters: the interesting case of Berkeley 21
- 1998MNRAS.299..834T