X/1872 X1, occasionally referred to as "Pogson's Comet", was a probable cometary astronomical object seen from Madras (now Chennai) on December 3 and 4, 1872, by astronomer N. R. Pogson. Pogson believed the object to be the lost Comet Biela, but subsequent orbital calculations have suggested that this was unlikely. Neither Biela's Comet nor Pogson's object have been recovered since, and the episode remains one of the most puzzling in solar system astronomy.