Abstract
BRORSEN'S COMET.—Of the known comets of short period, two will arrive at perihelion in 1884, viz. D'Arrest's on January 13, and Brorsen's about September. The former has been sought after for several months, but hitherto, so far as we are aware, without success, and there now seems a probability that (as indeed was rather to have been anticipated) it will pass unobserved at this return. The second comet was discovered by Brorser, an amateur at Kiel, on February 26, 1846, and ten days' observations sufficed to show that its period of revolution was about five and a half years: it afforded one of the most striking instances of a close approximation to the period being deduced from a short course of observation, Mr. Hind having inferred a revolution of 5.519 years from observations between February 28 and March 10 (Astron, Nach., No. 557), while the exact period at the time is now known to have been 5.568 years. The comet has been since observed at its returns in 1857, 1868, 1873, and 1879, though missed in 1851 (perhaps through some confusion as to the date of perihelion passage), and again in 1863. The ephemeris for the latt appearance in 1879 was prepared by Prof, L. R. Schulze of Dobeln, after the calculation of planetary perturbations since the return in 1873, the perihelion passage being fixed to March 30.0771 Greenwich M.T. The computed positions differed considerably from those observed, as was shown in M. Otto Struve's comparison with his own observations (Bulletin de l'Académie des Sciences de St. Petersburg, t. v.), and these differences led him to remark:—“Eiue Änderung in der angenommenen Perihelzeit würde fur sich allein wahrscheinlich nicht genügen.” It will be found, however, at the end of April or beginning of May. The errors may be removed by the assumption of a later time of perihelion passage; or by taking it March 30.5418 Greenwich M.T., a difference of + 0.4674d. from the computed epoch. Thus for the observation on April 30, we find, taking the differences in the order (c - o):—
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Our Astronomical Column . Nature 29, 88–89 (1883). https://doi.org/10.1038/029088a0
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DOI: https://doi.org/10.1038/029088a0