The solar constant

A detailed compilation of the most recent values of the solar constant is given (13 values published from 1967 to 1970). The most probable value seems to be 1.95 cal cm^–2 min^–1 or 1.36 kW m^–2 with a formal rms error of ± 0.3%. The corresponding effective temperature is 5770K.Systematic errors of the order of ± 1%, but also a possible variability of the same order cannot be excluded.