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Abstract
Measurement of solar radiation in 7 monochromatic regions, and measurements of total, diffuse and direct radiation, during the partial eclipse of Feb. 25th 1952 at N'dele (8° 24′ 25″ N 20° 40″ 0″ E) lead to a determination of solar limb darkening, even for the region between 99 and 100% of the sun's radius. The values of Minnaert (1953) and Peyturaux (1952) and (1955) are confirmed, the formula of Houtgast (1952) is shown to be incorrect.
This confirms the idea of Plaskett 1936 that there must be a very strong temperature gradient near the surface of the photosphere. Using the new formula from Warzée 1955 the constants for total radiation are computed and compared with the radiative equilibrium and with the case of a mean wavelength of 548.5 mμ. The difference with respect to the case of 548,5 mμ is due to the fact that the center of sun disc is bluer and the border region is redder than this wavelenght.