Dandekar B S, Turtle J P
Appl Opt. 1971 Jun 1;10(6):1220-4. doi: 10.1364/AO.10.001220.
Zenith sky brightness at totality was observed to be about four orders of magnitude lower than that for a normal day sky. The spectral distributions in terms of an effective blackbody temperature for the range 4100-8000 A were 5000 K, 9000 K, and 11,000 K for the twilight, control day sky, and totality, respectively, indicating a shift toward the shorter wavelength at totality. The polarization measured in the sun's vertical plane 90 degrees away from the sun was 4% and 0.6% at 4750 A and 6000 A, respectively. Both colors showed a change in the plane of polarization of about 50 degrees at the time of totality. From the change in the plane of polarization it is estimated from the primary component reduced by about an order of magnitude at totality of the eclipse.
观测到全食时天顶天空亮度比正常白昼天空亮度低约四个数量级。对于4100 - 8000埃范围，根据有效黑体温度得出的光谱分布，黄昏、对照白昼天空和全食时分别为5000 K、9000 K和11000 K，表明全食时向较短波长偏移。在与太阳成90度角的太阳垂直平面内测量的偏振，在4750埃和6000埃处分别为4%和0.6%。两种颜色在全食时偏振面都有大约50度的变化。从偏振面的变化估计，在日食全食时主要成分减少了约一个数量级。
