Faint CCD Photometry in Globular Clusters - Part Two - Comparison of Theoretical Isochrones with the Globular Clusters m4 and M15
The authors' CCD observations of M4 and M15 have provided precise and deep photometry for individual stars in these clusters. A comparison between the derived color-magnitude diagram and the theoretical isochrones of VandenBerg (1983) have shown that these new isochrones provide a very faithful representation of the observational data. To within an error of ±1 billion years, the ages of M4 and M15 are respectively 15×109 and 16.5×109 years.
Observational Tests of the Stellar Evolution Theory
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