VENUS IN THE PLEIADES.—A thousand years ago and later the geocentric track of the planet Venus was occasionally such as to cause it to traverse the Pleiades, a phenomenon which, in these telescopic days, would be one of no small interest to the observer; prior to the invention of the telescope its effect would be merely to obliterate in a great measure, for the time being, the stars forming this group, particularly when the planet happened to be upon them near an epoch of greatest brilliancy. Amongst the observations collected from the Chinese annals and forwarded to Europe in the middle of the last century by the French Jesuit, Gaubil, we find one made under the dynasty Tang, in the fifth year of the period Hwuy-Chang, on the day Jin-Woo, of the second moon—corresponding in the Julian Calender to A.D. 845, March 16—when “Venus eclipsed the Pleiades;” the observation appears to have been made at Si-gan-fou, where the Tang dynasty had their court, and where the earliest occultation of a star or planet by the moon, that of Mars B.C. 69, February 14, was also observed. If we found an examination of this “eclipse” of the Pleiades by Venus, upon Leverrier's data, using them with a sufficient degree of approximation for the purpose in view, it appears that at dusk at Si-gan-fou, on March 16, 845, Venus was situate near the star Electra, not far from the parallel of the principal star of the group Alcyone, but three-quarters of a degree to the west of it, and that about the same time on the evening of March 17, after having passed close to Maia, the planet would be in the same right ascension as Alcyone, about twenty-four minutes to the north. Although the so-called eclipse of the Pleiades might commence therefore on March 16 as the Chinese record, Venus would be more centrally upon the group on March 17, according to our modern tables. Her apparent diameter was then thirty seconds, and she would shine with more than average brilliancy. Another eclipse of the Pleiades is mentioned under the later Sung dynasty, on March 10, A.D. 1002.
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Journal of Physics A: Mathematical and Theoretical (2018)