On August 12, the first definitive proof that the solar corona is not made up chiefly of flaming coronal streamers alone, as has been supposed, but is an even, globular blanket covering the sun more than a million miles deep, was revealed by a conference of astronomers at Harvard Observatory.
Photographs leading to this finding were taken from an airplane in the substratosphere off the coast of Peru during the eclipse of June 8, under the direction of Army Major Albert W. Stevens, famous stratosphere explorer and member of the Hayden Planetarium-Grace eclipse expedition.
All of Major Stevens' plates clearly show a perfectly even corona surrounding the sun, at a depth considerably greater than the diameter of the body. His photographs include eleven pictures with a 24-inch camera, four pictures with an 8 1/4-inch camera, and 150 feet of motion picture film made with a 6-inch lens.
The usual familiar coronal streamers, which have completely dominated eclipse photographs taken from the ground, and which have absorbed most of the scientific attention up to now, appear on the new plates as relatively insignificant bright tracery in the immense globular envelope.
It is probable that the finding will affect the traditional method of eclipse observations, leading astronomers to make more use of airplanes to carry their instruments up into the substratosphere.
Guided by their new knowledge of the globular corona, the astronomers checked back and found that the phenomena was recorded on the Harvard totality photographs of last year, although by no means as clearly as on the stratosphere photographs. Earlier indications of the globular form of the corona had been obtained by the European astronomers Bergstrand and von Klueber, but the full appreciation of the nature of the corona was not reached until Major Stevens' photographs brought out the phenomenon more clearly than heretofore.
Major Stevens' important results were unexpected and essentially accidental. As one of the many field workers in the Hayden Planetarium-Grace expedition, directed by Dr. Clyde Fisher, of the Hayden Planetarium, New York, Major Stevens was primarily interested in getting high enough to photograph the spectacular course of the moon's shadow as it raced along the earth and cloud tops. His observations were made near Lima, Peru, in a Pan American Grace Airways plane.