The comet was discovered by English astronomer Edward Pigott from York, England, on 19 November 1783. The comet was located in the constellation of Cetus and he described it as a nebula with faint nucleus not visible in a good opera glass. He continued to follow the comet and noted that by 26 November it had dimmed. The comet was observed by Pierre Méchain on 26 November and Charles Messier the next day. Charles Messier mentioned that the comet was not visible to the naked eye, and described the comet as seen though a refractor as extremely faint nebulosity about 4 arcmin across with strong central condensation. The comet continued to dim and was last observed on 21 December 1783.[2] The initial orbits calculated assumed a parabolic orbit, but it didn't fit well enough the observed positions. An elliptical orbit was calculated by Christian Heinrich Friedrich Peters in 1860 indicated an orbital period of 5.89 years.[2]
The comet was recovered on 5 January 2003 by LINEAR. It was thought originally that it was an asteroid but further observations showed it was diffuse, having a coma 8 arcseconds across. Its apparent magnitude was estimated to be 18.4 at discovery. It was named C/2003 A1.[4] During the next apparition the comet was recovered by Richard Kowalski of Catalina Sky Survey on 10 September 2009, with an apparent magnitude of around 18. The comet was then identified as the same comet as P/1783 W1 and 2003 A1.[5] During the 2016 apparition it brightened up to an apparent magnitude of 13.9.[6]
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