Abstract
THE SOLAR PARALLAX.—In a communication to the Academy of Sciences of Paris on the 7th inst., M. Puiseux has discussed the observations of internal contacts during the last transit of Venus, which were made at stations occupied by the French expeditions. These include observations of second and third contacts at Pekin, St. Paul, Nagasaki, Saigon, and Kobé, and of second contact at Noumea. Seventeen equations are furnished by these data, and various combinations are made by Halley's method and by the method of Delisle. The former method supplies twelve separate results, the concluded parallaxes varying from 8″.78 to 9″.17, which are arranged according to the amount of the parallax factor: the simple arithmetical mean is 8″.98. On Delisle's method the combinations for second contact give fourteen values between 8″.86 and 9″.20, of which the mean is 9″.01, and those for third contact furnish ten values between 8″.63 and 8″90—the mean being 8″.92. These figures considered with respect to others which have been obtained from observations of the same transit and oa other methods, cannot be said to enlighten us materially as to the true amount of the sun's mean parallax. M. Puiseux thinks the observations of contact in 1874 have not given results so accordant as astronomers had looked for, but he nevertheless is far from discouraging efforts to secure observations of contacts in 1882; the phenomena in 1874 did not present that geometrical simplicity which had been formerly expected, but presented a succession of phases which were the more difficult to identify in the records of the observers according as the telescopes employed were more dissimilar; and he urges (1) that the different stations should be provided with telescopes of large aperture, to be employed under as identical circumstances as practicable, and (2) that the observers should be exercised “à l'aide d'appareils convenables,” to appreciate in the same manner the appearances which the contacts may offer. The former consideration at least is too well understood as of paramount importance to be likely to be overlooked by any of the national committees now engaged in arranging for the most efficient observation of the transit in 1882.
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Our Astronomical Column. Nature 23, 493–494 (1881). https://doi.org/10.1038/023493a0
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DOI: https://doi.org/10.1038/023493a0