Solar Brightness Distribution at a Wavelength of 60 Centimetres. I. The Quiet Sun

Abstract

A multiple-element interferometer has been employed to determine one-dimensional distributions of radio brightness over the quiet Sun at a wavelength of 60 cm for scanning directions varying from 90° to 60° with respect to the central meridian of the Sun. These observations have been compared with measurements by other workers at the same, or nearly the same, wavelength. The present observations are reasonably consistent with the two-dimensional brightness distribution derived recently by O'Brien and Tandberg-Hanssen with a two-aerial interferometer, but do not agree with the earlier results of Stanier at the same wavelength. The disagreement, largely the absence of the theoretically predicted limb-brightening in Stanier's results, may reflect actual changes in the Sun over the solar cycle. However, the possibility of localized disturbed regions affecting Stanier's results for the quiet Sun cannot be eliminated.