Study of the continuous solar spectrum in the visible range

Abstract

Limb darkening observations made under excellent observing conditions are given for twenty-two wavelengths in the continuous spectrum of the sun in the region λ 3600-λ 6800; these observations were made at a time when the disc was completely free from spots and also other forms of solar activity were at a minimum. It is verified that for the visible region between λ 4000 and λ 6000 the variation of continuous absorption coefficient with wavelength agrees with the theoretical values given by CHANDRASEKHAR and BREEN for the H-ion. However beyond 6000 Å divergence between theory and observation begins to appear, Variation of optical depth with temperature for λ 5000 is deduced from observations.