Left: observed distribution of log and (B − V) in the M 67 and NGC 188 clusters. The number of stars in each cluster’s average is indicated. The distribution of colors, and thus also of T_effs and mass, is very similar in the two clusters. The Sun is plotted as the ⊙ symbol. Right: log for M 67, NGC 188, and the Sun plotted against the age-mass-metallicity-activity relation for 1.0 (upper) and 1.1 solar masses (lower solid line). The blue dash-dotted lines stand for MH08 ACAR for (B − V) = 0.6 (lower) and 0.7 (upper). The red dashed line is the CA-age relation from MH08. Vertical bars are age uncertainties; horizontal bars are observed dispersions in log.