Page:The story of the comets.djvu/154

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112
The Story of the Comets.
Chap.

was a date a fortnight later than Pontécoulant's and 3 weeks later than Damoiseau's.[1]

As early as Dec. 1834, astronomers began to direct their telescopes to that part of the heavens where it was supposed that the comet would be first seen. Olbers had thrown out suggestions that it might be possible to find the comet between Dec. 1834 and April 1835, notwithstanding that the perihelion passage would not take place till many months later. Olbers's suggestion was largely acted upon, for it applied to the constellations Auriga and Taurus which were very favourably placed for observation in Northern and Central Europe, while Sir John Herschel at the Cape employed his great reflector also in sweeping for the anxiously expected body. But all these early efforts were wasted.

It was not until the morning of Aug. 6 that the first view of the comet was obtained, and the fortunate man was Dumouchel, director of the Collegio Romano Observatory at Rome, using a powerful telescope in a splendid climate. The comet was close to the computed place which was near ζ Tauri. It was a faint, misty object, discernible with difficulty, and moonlight and unfavourable weather during the next following days delayed the comet's discovery elsewhere. However, on Aug. 21 W. Struve found it with the great telescope at Dorpat, and during the following week it was seen at all the principal English and Continental observatories. The Dorpat observations showed that Rosenberger's predicted place was only 7' of arc wrong in R. A. and 17' in Declination. The effect of this error was to retard the perihelion passage till Nov. 16, or 5 days later than the epoch fixed upon by Rosenberger. During the first 3 weeks of Sept. the comet's brightness gradually increased, and on the 23rd it was seen with the naked eye by Struve, and on the following day with the naked eye by Kaiser at Leyden, though it was not

  1. The distracting effect of planetary perturbations on the movements of comets is shown by the fact that whereas the interval between the perihelion passages of Halley's Comet in 1835 and 1910 is to be set down at 74 years 51/2 months (the shortest on record), in 1222 and 1301 it was 79 years 2 months (the longest on record, the next longest having been 1066 and 1145).