Photometry of dwarf K and M stars

An observational program using UBVRI photometry is presented for 688 stars from among the dwarf K and M stars already found spectroscopically by Vyssotsky (1958). Of these, 211 have not been observed photometrically. These observations were obtained over a period of several years at the Kitt Peak National Observatory using a GaAs photomultiplier with an 0.9 m reflector. Based on night-to-night variations in the measures of individual stars, the internal errors may be estimated to be roughly 0.01 mag for the colors and 0.015 for the V magnitudes. The photometric parallaxes reported for each star were computed in the manner discussed by Weis (1986).