Abstract
DISPLACEMENT OF LINES IN THE SPECTRUM OF VENUS.—The Astrophys. Journ. for June contains a paper by Dr. Chas. E. St. John and Mr. Seth B. Nicholson, in which they test the result announced by Mr. Evershed that his Venus spectrograms supported the view that the earth exerts a repulsive effect on the solar gases, analogous to that which the sun appears to exert on comets' tails. The authors took two series of Venus spectrograms: in 1919 with Venus east of the sun, and in 1919–20 with Venus west of the sun. Their analysis of the results leads them to conclude that the effect can be correlated with the altitude and the angular diameter of Venus; hence they conjecture othat it is due to atmospheric dispersion, the centre of the visual image which was adjusted on the slit differing from the centre of the photographic image. They propose in future to take some further plates viewing the image through a blue screen, which should eliminate the above source of error. They have incidentally examined the measures to see if they afford any evidence of a rapid rotation of the planet, but conclude that “the difference between the morn ing and evening series … is not of an order that would indicate … a rate of rotation higher than that found by Slipher.” In all the plates of the series, whether on Venus, the sky, or the sun, an iron-arc spectrum was photographed simultaneously.
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Our Astronomical Column. Nature 107, 725 (1921). https://doi.org/10.1038/107725b0
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DOI: https://doi.org/10.1038/107725b0