Relationships between the Johnson and Kron-Cousins VRI photometric systems

Abstract

VRI transformations between the photometric systems of Johnson and Kron-Cousins are investigated using the new Johnson standards now appearing in The Astronomical Almanac. Linear solution transformations are obtained for (V-R), (V-I), and (R-I), with transformations for very red stars being determined separately. There is no significant discontinuity in passing from the less red stars to the very red ones. No significant trend is apparent in the residuals between the observations and values predicted by the equations. The agreement with the previous work of Cousins (1980) and Bessell (1979) is good.