The Great Comet of 1264 (C/1264 N1) was a comet that appeared on July 17, 1264 that could be seen with the naked eye. It remained visible until the end of September. It is one of the brightest comets on record. It first appeared during the evenings after sunset, but in the weeks following was visible during the mornings in the northeastern sky, with the tail perceived long before the comet itself rose above the horizon. The head of the comet seemed like an obscure and ill-defined star, and the tail passed from this portion of it like expanded flames, stretching forth towards the mid-heavens to a distance of one hundred degrees from the nucleus. The comet of 1264 was described to have been an object of great size and brilliancy.
The comet was at its brightest in the end of August and at the beginning of September. At that time, when the head was just visible above the eastern horizon in the morning sky, the tail stretched out past the mid-heaven towards the west, or was nearly 100° in length.
Many chroniclers of the time linked the appearance of this comet to the death of Pope Urban IV. It is said that he fell ill on July 17, the exact day the comet appeared. He later died on the exact date it disappeared, October 3, 1264. It was said that the "prodigy of a hairy star" brought upon his illness, and "slipped away when the job was finished". Giovanni Pontano would describe in his Commentarii in centum Claudii Ptolemaei sententias a series of deadly events that were said to have occurred several years after the comet had appeared.
Observation[]
The comet was visible and observed in Europe, China, Korea, and Japan. The descriptions written by the Chinese astronomers are identical to those of the European ones.
Alleged connections to the Great Comet of 1556[]
Some astronomers have speculated that this may be the same comet as the Great Comet of 1556. Alexandre Guy Pingré in his Cométographie (1783) calculated the comet's parabolic orbit and found great similarities to the Comet of 1556. The comet of 1264 "is very probably the same as that of 1556; its periodical revolution is about 292 years; and its return may consequently be expected about 1848", said Pingré. The comet did not reappear in 1848.
John Russell Hind said in On the expected return of the great comet of 1264 and 1556: "My calculations relating to the Comet have been pretty extensive, and I have not omitted to examine closely all the circumstances recorded respecting it. The conclusion at which I have arrived is this,-- that there is a very high probability in favour of the supposed identity of the Comets of 1264 and 1556".
Amédée Guillemin would write in 1877; "Its return was first expected in 1848. 'But 1849, 1850, 1851, and 1852 have passed, and the great comet has failed to appear!' ... Splendid comets appeared in 1858, 1861, and 1862, but the comet of Charles V. never returned... [T]he comet of 1264 and 1556 must be considered lost; and if in reality merely accidental causes prevented its being observed, and it should appear again, it will be our descendants in the twenty-second century who will have the satisfaction of celebrating its return"
Comets sometimes disappear because or obital derangement from an ellipse to a parabola or a hyperbola. Sir Isaac Newton showed that a body controlled by the Sun moves in a conic section - that is, an ellipse, a parabola or a hyperbola. Because the latter two are open curves, a comet which pursued such a path would go off into space never to reappear. A derangement of orbit from closed to open curve has doubtless happened often.