Photographs of the Solar Granulation Taken from the Stratosphere.

A 12-inch solar telescope equipped with a photoelectric pointing mechanism and an automatic camera has been flown by unmanned balloons to an altitude of 80000 feet. A number of photographs of the solar granulation obtained with this telescope are of very high definition and show the granulation to have the character of non-stationary convection. The bright granules, ranging in diameter from about 300 to about 1800 km, are of highly irregular, often polygonal, shape and are separated from one another by dark, often very narrow, lanes. The root-mean-square temperature fluctuation, uncorrected for instrumental smoothing, is found to be only + 60 . The analysis suggests that the true root-mean-square temperature fluctuation is probably not larger than * 100 .