Radio observations of the quiet sun at 49 cm

Abstract

The brightness distribution over the quiet Sun was investigated at wavelengths of 50 and 60 cm by Panovkin and Ovsiankin and O'Brien and Tandberg-Hansen with the help of two aerial interferometers during the years 1954 and 1955. Both series of observations showed much less limb brightening than was predicted theoretically on the basis of optically derived values of electron densities and temperature in the solar corona. The disagreement was explained by assuming that inhomogeneities in the solar corona scatter radio waves. Observations made using an interferometer of high resolution located near Bombay are found to be consistent with theoretical distributions based on a smooth corona and indicate that earlier measurements may be unreliable because of insufficient resolution.