Measurements of the zenith sky brightness and color during the total solar eclipse of 12 november 1966 at Quehua, Bolivia.

The brightness and the spectral distribution of the zenith sky in the 5300-6600 A region were measured during the eclipse of 12 November 1966 at Quehua, Bolivia. At totality, the brightness at 5600 A was observed to be 8.4 kR/A, three orders of magnitude lower than the 2.2 x 10(4) kR/A for the normal day sky. The spectral distribution is presented here in terms of a single parameter, the effective blackbody temperature for determining the predominance of secondary scattering during midtotality. The effective temperature was observed to change from 9100 degrees K for normal day sky to 11,100 degrees K during totality.