Color Portion of Solar Radiation in the Partial Annular Solar Eclipse, October 3rd, 2005, at Helwan, Egypt

Abstract

Measurements were made of various solar radiation components, global, direct and diffuse and their fractions during the partial annular solar eclipse on October 3^rd, 2005 at Helwan, Egypt (Lat. 29.866◦ N and Long. 31.20◦ E), and an analysis has been made. The duration of the solar eclipse was 3 h 17 min, and the maximum magnitude of the eclipse in this region was 0.65. The optical depth of the direct component and the relative humidity decreased, while both the transparency and the air temperature increased towards the maximum eclipse. The general trends of the global components are decreasing optical depth and increasing transparency between the first contact and the last contact. The prevailing color during the eclipse duration was diffused infrared (77 % of the total diffuse radiation level).