Deflection of Light during a Solar Eclipse

Abstract

MR. ORANGE'S point is, of course, that we should use the one object in the field of which the light has not been through the sun's gravitational field in order to get rid of the Einstein disturbance; also of the suggested refraction by gases near the sun. I have talked the matter over with Mr. C. Davidson, who agrees with me that nothing is to be done with existing photographs in this direction—the exposures where too long, and the moon's limb too ill-defined; but it is possible that in future eclipses short exposures, given specially for the purpose, might vield something of interest. The chief difficulty is that we do not know the moon's dark photographic diameter. It cannot be assumed equal to the bright photographic diameter, for irradiation (and other similar actions) go in the reverse direction.