An Artificial Representation of a Total Solar Eclipse

Abstract

IN preparing for polarisation experiments on the solar corona, it is extremely desirable to have an artificial corona as nearly as possible resembling the reality for preliminary work. The only device of the kind that has been used to my knowledge was the arrangement described by Wright in his eclipse report, consisting of a cardboard funnel, lined with black cloth, with a light at the back. This gives a ring-shaped illuminated area radially polarised. It is believed that the contrivance about to be described will be found far better adapted to work of this sort, for the artificial corona in this case resembles the real so closely as to startle one who has actually witnessed a total solar eclipse. The polarisation is radial, and is produced in the same way as in the sun's surroundings, and the misty gradations of brilliancy are present as well. So perfect was the representation that I added several features of purely æsthetic nature to heighten the effect, and finally succeeded in getting a reproduction of a solar eclipse which, could hardly be distinguished from the reality, except that the polar streamers are straight, as drawn by Trouvelot, instead of being curved, as all the recent photographs show them. The curious greenish-blue colour of the sky, and the peculiar pearly lustre and misty appearance are faithfully reproduced. For lecture purposes an artificial eclipse of this sort would be admirably adapted, and I know of no other way in which an audience could be given so vivid an idea of the beauty of the phenomenon. Drawings and photographs are wholly inadequate in giving any notion of the actual appearance of the sun's surroundings, and I, feel sure that any one will feel amply repaid for the small amount of trouble necessary in fitting up the, arrangement which I shall describe.