MK Classifications of Close Visual Binaries

These classifications are shown to be on the MK system. Two sources of area scanner UBV photometry were compared in order to establish homogeneous photometric as well as spectroscopic data.

From a consideration of systematic errors in the V magnitude difference between components the photometry of Hurly and Warner is to be preferred. Absolute magnitudes for each binary are derived from magnitude difference via a tested MK-Mv map.