Limits to Solar Limb Darkening at a Wavelength of 1.4 Millimeters Derived from Antenna-Beam Parameters

Abstract

Careful studies have been made to derive the performance characteristics of the NRAO 1 1-m dish in the 0.8-1.6 mm wavelength range. It is shown that incomplete reduction of data previously obtained with the same instrument has led certain authors to the erroneous conclusion that limb darkening exists at short millimeter wavelengths. Within the available resolution of the dish (with the error pattern deconvolved) the quiet-Sun brightness distribution is rectangular, with some indication of polar darkening. Subject headings: instruments - limb darkening, solar - radio radiation, solar