UBV Photometry of 300 G and K Type Stars

Magnitudes and colours are given for about 300 G and K type stars (classes I to V) derived from photoelectric measurements made at the Kitt Peak National Observatory and reduced as accurately as possible to the UBV system. The standard error of a single observation, as determined from the internal scatter, is about 0 m .02 in V and 0 m .01 in ( B – V ) and ( U – B ), but as always in work of this kind, careful distinction must be made between internal errors and true errors. Compensation for instrumental characteristics is slightly incomplete, with the result that for ( B – V ) greater than 0 m .9 the class II and III stars are given systematically redder than Johnson's values by about 0 m .01 in ( B – V ).