Abstract
PONS' COMET.—Several observers have drawn attention to a remarkable fluctuation in the brightness of this comet in September. M. Bigourdan of the Paris Observatory says that on the 5th of that month it appeared as a faint nebulosity about equal in brightness to a star of the twelfth magnitude, and nearly round. On the gth, with a power of 500, there was a small nucleus, ill defined but sufficiently distinct from the surrounding nebulosity; the comet's light had increased since the 5th. Moonlight and clouds interfered with observation till the 23rd, when the brightness was much increased, and in a small telescope was equal to that of a star of the eighth magnitude. On the following night, in a fine sky, the comet's aspect was still the same, and its diameter was nearly 2′. On the 27th a considerable change had taken place; the nebulosity was much fainter, and the nucleus distinct from it was from 10-11m. After that date the nucleus further diminished, and on October 6 was only of 12m., though the comet as a whole was more easily seen than at the beginning of September. Thus on September 24 the comet was of 8m., while its brightness, calculated from that of September 5, would have assigned it only 11-12m. It therefore had, as M. Bigourdan remarks, for some time a brightness thirty to forty times that given by theory, which, he says, it is difficult to reconcile with the opinion that comets have not a light of their own.
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Our Astronomical Column . Nature 28, 624–625 (1883). https://doi.org/10.1038/028624a0
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DOI: https://doi.org/10.1038/028624a0