ON THE THORY OF THE DAYTIME SKY BRIGHTNESS UNDER CONDITIONS OF A SPHERICAL EARTH,
Abstract
Existing theories of daytime sky brightness hold only for the flat earth case, and thus are inapplicable near the horizon; they cannot be generalized to deal with twilight. Yet when the sun is low over the horizon the atmosphere is virtually in the twilight state even during the daytime, since its lowest layers are acting only to decrease the sky brightness by their absorption of light. This report gives a more general theory of sky brightness developed for the case of a spherical earth; it was been found to be in good agreement with observations when the atmosphere is in a stable state. The theory is also generalized to cover the case of an observer at different altitudes above the surface of the earth. The density of the atmosphere is assumed to vary according to an exponential law. The index of light scattering is taken as invariable throughout the whole thickness of the atmosphere. Only scattering of the first order is considered. The compilation of auxiliary tables of atmospheric masses along the observer's line of sight, and along the solar rays illuminating any given volume of the atmosphere, permits the sky brightness to be evaluated at any point above or below the astronomical horizon. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1958
- Accession Number
- AD0610965
Entities
People
- V. G. Fesenkov