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Discovery
Edward Pigott (York, England) discovered this comet on 1783 November 19.96, in the constellation of Cetus. He described it as looking like a nebula, with a diameter of about 2-3 arcmin, and not visible in a good opera glass. He added, "The nucleus being very faint, is seen with some difficulty, when the wires of the instrument are illuminated." Pigott confirmed the discovery on November 20.95.
Historical Highlights
Several astronomers observed the comet in the evening sky as November progressed. Pigott reported that the comet was unchanged in appearance on November 21, but that it had diminished in brightness by the 26th. John Goodricke (England) measured the comet's position on the 24th and 28th. P. F. A. Méchain (Paris, France) independently discovered the comet near 31 Arietis on November 26.87. He described it as a shapeless nebulosity, with a center that was a little brighter than the surrounding coma, but with no tail. Méchain added that the comet was about 1.5 arcmin across, and was impossible to see with the naked eye. Charles Messier (Marine Observatory, Paris, France) first saw the comet on the 27th and said that, while the comet was not visible to the naked eye, a refractor revealed an extremely faint nebulosity about 4 arcmin across. He noted a strong central condensation. Messier's observation on the following night indicated that the comet had faded. William Herschel (Slough, England) saw the comet on the 29th and estimated the diameters of the coma and nucleus as 8 arcmin and 3 arcsec, respectively. Messier also saw the comet on this date and reported that it was unchanged in brightness since the previous night. Moonlight interfered with observations as December began and Pigott, Messier, and Méchain all reported that the comet was difficult to see on the 2nd. Messier continued to have difficulty on the 3rd, while Pigott reported it as very difficult to see on the 4th. Pigott said "the comet was entirely effaced by the increased light of the moon," from December 5 to 10. On the latter date, before moonrise, he searched for the comet but failed to locate it, despite seeing stars of magnitudes 8 and 9. Observations resumed on the 11th when Méchain saw the comet before moonrise. He noted that, although the comet had not sensibly diminished in brightness and size since the 2nd, it was still extremely faint and difficult to observe. Messier described it as faint on the 12th and still fainter on the 14th. By the 18th Messier had to search for some time before the comet was located and he reported that it was difficult to see. The next evening Messier said it had become a little fainter, and that "positional measurements were difficult." The comet was last detected on December 21.74 by Méchain and on December 21.81 by Messier. Messier said the comet was extremely faint. He added that the sky was cloudy from December 22 for several days. He concluded that the comet was thereafter too faint to have been seen again.
At the end of 1783, the Chevalier Jean Auguste d'Angos (Malta) wrote to Messier and noted that Messier's positions could not be completely satisfied by a parabolic orbit; Nevertheless, parabolic orbits were computed by Méchain and Jean Baptiste Gaspard Bochart de Saron during 1783. Méchain's orbit indicated a perihelion date between November 13 and 21, figures which would prove somewhat close to the final orbit, while Bochart de Saron's orbit gave a perihelion date of October 23. Messier pointed out that each of the orbits failed to represent some of the positions adequately. Later astronomers found that elliptical orbits more successfully represented the positions. J. K. Burckhardt (1820) computed two such orbits, with orbital periods of 5.61 years and 10.03 years, while C. H. F. Peters (1860) determined a period of 5.89 years.
On the night of January 5, 2003, the Lincoln Near Earth Asteroid Research (LINEAR) program located in New Mexico (USA) found an asteroidal object on three images obtained using their 1.0-m telescope.
cometography.com
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