The 1954 Eclipse Measurement of the 8.6-MM Solar Brightness Distribution.

Abstract

The solar eclipse of June 30, 1954, was observed at the 8 6-mm wave length from a site in Sweden near the eclipse center line, and the brightness distribution across the solar disk was determined. This brightness-curve is essentially flat from the sun's center out to about 0 6 solar radius, dips slightly to a minimum at about 0 9 solar radius, rises to a peak just outside the optical limb, and falls off rapidly beyond the peak. The limb of the 8 6-mm sun is 4740 + 300 km above the optical limb.