Abstract

This paper describes a radiative transfer model for estimating the brightness or radiance of the sky during a total solar eclipse. The model is approximate; it only considers sunlight that diffuses into the umbra by first- and second-order scattering processes. It nevertheless correctly predicts the major observed features of the eclipsed sky including reddening of the horizon and lowering of zenith radiance over the normal day value by approximately 4 orders of magnitude. The calculated absolute zenith radiance at blue wavelength is about 20% lower than observed during the 1973 African solar eclipse. The model predicts, and observations confirm, that the zenith has the highest blue–red ratio (color temperature) and lowest brightness of any place in the sky during totality.

© 1978 Optical Society of America

Sky color near the horizon during a total solar eclipse

Stanley David Gedzelman
Appl. Opt. 14(12) 2831-2837 (1975)

Sky Brightness and Polarization During the 1973 African Eclipse

Glenn E. Shaw
Appl. Opt. 14(2) 388-394 (1975)

Measurements of the Zenith Sky Brightness and Color During the Total Solar Eclipse of 12 November 1966 at Quehua, Bolivia

B. S. Dandekar
Appl. Opt. 7(4) 705-710 (1968)

Spatiotemporal change of sky polarization during the total solar eclipse on 29 March 2006 in Turkey: polarization patterns of the eclipsed sky observed by full-sky imaging polarimetry

Brigitta Sipoćz, Ramón Hegedüs, György Kriska, and Gábor Horváth
Appl. Opt. 47(34) H1-H10 (2008)

Digital all-sky polarization imaging of the total solar eclipse on 21 August 2017 in Rexburg, Idaho, USA

Laura M. Eshelman, Martin Jan Tauc, Taiga Hashimoto, Kendra Gillis, William Weiss, Bryan Stanley, Preston Hooser, Glenn E. Shaw, and Joseph A. Shaw
Appl. Opt. 59(21) F41-F52 (2020)