Emission gradients in the continuum at the sun's limb

The intensity variation at the sun's limb has been studied in order to derive the gradient of the temperature in the low chromosphere. Eclipse observations show that in the continuum the height gradients of the total intensity vary systematically with wavelength; the observed gradient in the red is found to be steeper than in the blue. This wavelength dependence of the gradients is explained by the temperature increase in the low chromosphere.