Fig. 1 Comparison of observational (circles) and best fit theoretical (squares) CMDs, for globular
clusters NGC 104, NGC 2419, NGC 4147, and NGC 4372, respectively. The theoretical CMDs are
calculated from binary-star populations with 50% binaries and each star is assumed to be discriminable.
In the field shown in the figure, the observational and theoretical CMDs contain the same
stars, but a few red points contain less than 1 star.