Revised Zero Points and UBV Photometry of Stars in the Harvard E and F Regions

Abstract

New observations in the UBV system of about twenty of the brighter stars in each of the nine E regions and three F regions have recently been made, primarily to check and revise the zero points of the magnitude sequences in those regions. The internal standard errors of the new E region zero points are ±0 ^m .0016 for V , ±0 ^m .0005 for B−V and ±0 ^m .0006 for U−B . The largest difference between the old and the new zero points is 0 ^m .008 (in U−B ). The values of V and B−V in R. Obs. Bull. No . 49 also need corrections similar to those applied to Cape measures of bright stars included in R. Obs. Ann. No. 7 . There are differences of zero point, amounting to 0 ^m .01 for one of the F regions, and some differences of colour equation between the old and new series there. U−B has now been measured for more stars in these sequences. In all regions the new data appear to be more reliable than the old.