NGC 6231

Number of stars per data source

	Reference   56 :   10 stars
	Reference  128 :   45 stars
	Reference  198 :  513 stars

56: Shapley H., Sawyer H.B.; (1927) Harvard Coll. Obs. Bull. no 846; The galactic cluster NGC 6231
128: Lasker B.M., Russel J.N., Jenkner H., Sturch C.R., McLean B.J., Shara M.M.; (1990) Astron. J. 99, 2019; The HST guide star catalogue, version 1.0; 1990AJ.....99.2019L
198: Sung H., Bessell M.S., Lee s.-W.; (1998) Astron. J. 115, 734; UBVRI Halpha photometry of the young open cluster NGC 6231; 1998AJ....115..734S