The David Dunlap Observatory (DDO) intermediate-band photometric system has been used to observe late-type globular cluster stars for the purpose of obtaining physical data suitable for comparison with the predictions of theoretical Population II evolutionary calculations. The system has been calibrated such that the DDO colors of any star may be used to determine its [Fe/H], its effective temperature, and its surface gravity. These quantities have been derived from observations of several Red Giant Branch, Horizontal Branch, and Asymptotic Branch members in each of the clusters M3, M5, M10, M13, and M92. By adopting distance moduli for the clusters, absolute magnitudes and estimates of the masses of the observed stars were also obtained. From the data, mean [Fe/H] values for the five clusters of -1.01 for M3, -0.68 for M5, -1.44 for M10, -1.69 for M13, and -1.96 for M92 (with with errors of +/- 0.3) have been derived. Evidence has been found that the masses of the Horizontal and Asymptotic Branch stars are systematically lower than those for Red Giant members. Two of the investigated stars have been found to have anomalously strong CN band strength. A star that appears to have a considerably lower surface gravity than would be expected for a globular cluster star of its temperature has been discovered. It is shown that observations with the DDO system are well suited for separating cluster members from field interlopers. The observational results have been compared with the predictions of two Population II evolutionary tracks and in general the agreement is good.
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