Description: Average intensity profile of the solar corona, logarithmic scale. The curve is based on the empirical formula

${\displaystyle {I(R) \over I_{0}}=10^{-6}\left({\frac {3{,}670}{R^{18}}}+{\frac {1{,}939}{R^{7{,}8}}}+{\frac {0{,}0551}{R^{2{,}5}}}\right)\ ;\quad R>1}$,

where I₀ is the intensity in the middle of the apparent solar disc and R is the angular distance from the middle in units of the angular radius of the sun's disc.

• Author: SiriusB
• Source: L. J. November, S. Koutchmy: White-Light Coronal Dark Threads and Density Fine Structure, Astrophysical Journal, 466, S. 512ff, Juli 1996 (the formula). Plotted with Gnuplot.
• See also: Image:Solar Middle-Edge Variation.png