ABSTRACT
The high temperature sensitivity of the line-depth ratio V I lambda-6251.83 to Fe I lambda-6252.57, measured in the daytime sky, is used to infer the color indices of the sun: B-V = 0.656 ± 0.005, b-y = 0.414 ± 0.003, and B2-V1 = 0.393 ± 0.004.