1995PASP..107..351J

We have measured stars in Praesepe and NGC 752 in an internally-consistent Stromgren-Beta system. This system is based in large part on published Hyades and Coma measurements. On comparing our Praesepe results to those of Crawford and Barnes (1969, AJ, 74, 818), we find that the published color indices require corrections of 10-18 mmag to put them on the Hyades-Coma system. This deduction applies for b-y, m_1 and Beta (but not c_1). For the NGC 752 data of Crawford and Barnes (1970, AJ, 75, 946), we obtain a nonzero correction only for Beta. This correction is about 9 mmag. Also for NGC 752, we find that the data of Twarog (1983, ApJ, 267, 207) require corrections ranging from 4-17 mmag, with all Stromgren indices being affected and the largest correction being for m_1. These corrections resolve the long-standing proglem posed by the differences between the Twarog and Crawford-Barnes data. For three published sources of V magnitudes, we obtain offsets ranging from -14 to +27 mmag relative to our zero point, and we suggest that such offsets are fairly common in published photometry for galactic clusters. For Praesepe, we use new and corrected data to test for a c_1 anomaly and is indistinguishable from Coma in that regard.