Its total mass is not known with certainty, but, assuming that Halley's comet is a suitable prototype for all comets within the outer Oort cloud, the estimated combined mass is ( or roughly five times the mass of the Earth ).

* 2135-2136 Halley's comet will be at perihelion.

* September 7 – A large comet is observed in Japan ( it's Japan's oldest observation record of the Halley's Comet ).

* September – Halley's comet makes an appearance, just like Edmond Halley predicted before his death.

Han Chinese astronomers made star catalogues and detailed records of comets that appeared in the night sky, including recording the 12 BCE appearance of the comet now known as Halley's comet.

However, observations conducted around the time of Halley's Comet's appearance in 1986 suggest that the Eta Aquarid meteor shower might not originate from Halley's Comet, though it might be perturbed by the comet.

For example, " 1P / 1982 U1, 1986 III, 1982i " indicates that for the perihelion in 1986, Halley's Comet was the first period comet known ( designated 1P ) and this apparition was the first seen in " half-month " U ( the first half of November ) in 1982 ( giving 1P / 1982 U1 ); it was the third comet past perihelion in 1986 ( 1986 III ); and it was the ninth comet spotted in 1982 ( provisional designation 1982i ).

The first certain appearance of Halley's Comet in the historical record is a description from 240 BCE, in the Chinese chronicle Records of the Grand Historian or Shiji, which describes a comet that appeared in the east and moved north.

" Gurzadyan and Vardanyan argue that " Tigranes could have seen Halley's Comet when it passed closest to the Sun on August 6 in 87 BCE " as the comet would have been a " most recordable event "; for ancient Armenians it could have heralded the New Era of the brilliant King of Kings.

In 912, Halley's comet is recorded in the Annals of Ulster, which state " A dark and rainy year.

I came in with Halley's comet in 1835.

It will be the greatest disappointment of my life if I don't go out with Halley's comet.

On 8 November 1985, Stephen Edberg ( then serving as the Coordinator for Amateur Observations at NASA's Jet Propulsion Laboratory ) and Charles Morris were the first to observe Halley's comet with the naked eye in its 1986 apparition.

The picture of Halley's Comet, which appears in the upper border ( scene 32 ), is the first known picture of this comet.

* 1758 – Johann Palitzsch observes the return of Halley's comet.

Parisian astronomer La Caille suggests it should be named Halley's comet.

Halley's comet and the Great Comet of 1843, and took an active part in the verification and extension of Nicolas Louis de Lacaille's arc of the meridian.

On December 4, 1985, the United States Postal Service issued a stamped envelope for " Mark Twain and Halley's Comet ," noting the connection with Twain's birth, his death, and the comet.

However, although Schwarzschild's best known work lies in the area of general relativity, his research interests were extremely broad, including work in celestial mechanics, observational stellar photometry, quantum mechanics, instrumental astronomy, stellar structure, stellar statistics, Halley's comet, and spectroscopy.

He observed Halley's comet in 1835 from Landulph and the following year started to make his own astronomical calculations, predictions and observations, engaging in private tutoring to finance his activities.

Halley's orbital period over the last 3 centuries has been between 75 – 76 years, though it has varied between 74 – 79 years since 240 BCE.

Observations by D. W. Hughes suggest that Halley's nucleus has been reduced in mass by 80 – 90 % over the last 2000 – 3000 revolutions.

* July 28 – Halley's Comet reaches its perihelion, the closest point to the Sun — the last return reached its perihelion on February 9, 1986.

According to one story that first appeared in a 1475 posthumous biography and was subsequently embellished and popularized by Pierre-Simon Laplace, Callixtus III excommunicated the 1456 apparition of Halley's Comet, believing it to be an ill omen for the Christian defenders of Belgrade from the besieging armies of the Ottoman Empire.

Later scholars, such as the American historian of technology Lynn White, have attempted to estimate Eilmer's date of birth based on a quotation in William's Deeds in regard to Halley's comet, which appeared in 1066.

The Halley's Comet's tail has always appeared as a long, straight line and does not resemble the curves of the Serpent Mound.

The mentioned brightly visualised comet that appeared in the said month of March and April points to the Halley's comet of 141 CE ( February – April 1 week ).

Halley's returns to the inner Solar System have been observed and recorded by astronomers since at least 240 BCE.

It became a part of the Halley Armada together with Suisei, the Soviet / French Vega probes, the ESA Giotto and the NASA International Cometary Explorer, to explore Halley's Comet during its 1986 sojourn through the inner solar system.

It constituted a part of the Halley Armada together with Sakigake, the Soviet / French Vega probes, the ESA Giotto and the NASA International Cometary Explorer, to explore Halley's Comet during its 1986 sojourn through the inner solar system.

Halley's Comet, for example, is usually very bright when it passes through the inner Solar System every seventy-six years, but during its 1986 apparition, its closest approach to Earth was almost the most distant possible.

The Halley Armada is the generally accepted and popularly used name of five space probes sent to examine Halley's Comet during its 1986 sojourn through the inner solar system, connected with apparition " 1P / 1982 U1 ".

The latter group, which is named for its prototype, Halley's Comet, are believed to have emerged from the Oort cloud but to have been drawn into the inner Solar System by the gravity of the giant planets.

Unusually for an object in the Solar System, Halley's orbit is retrograde ; it orbits the Sun in the opposite direction to the planets, or clockwise from above the Sun's north pole.

In 2061, at the age of 103, Floyd is chosen as one of several " celebrity guests " to come aboard the privately owned spaceliner Universe for the first-ever human landing on the surface of Halley's Comet, when it makes its periodic pass through the Solar System.

* 1986 – The Soviet Vega 1 begins returning images of Halley's Comet and the first images of its nucleus.

Halley's 1986 apparition was the least favorable on record.

The next predicted perihelion of Halley's Comet is 28 July 2061, when it is expected to be better positioned for observation than during the 1985 – 1986 apparition, as it will be on the same side of the Sun as Earth.

* 1986 – The Giotto probe provides the first ever close up images of Halley's Comet.

On 13 March 1986, the mission succeeded in approaching Halley's nucleus at a distance of 596 kilometers.

In February 1986 he presented a special Sky at Night episode on the approach of Halley's Comet, though he later stated that the BBC's better-funded Horizon team " made a complete hash of the programme.

It carried out a flyby of Halley's Comet on March 11, 1986 at a distance of 6. 99 million km.

* Giotto ( spacecraft ), approached Halley's Comet in March 1986 ( made at Filton )

The appearance of the Daylight Comet several months earlier therefore came as something of a surprise, and made an extremely strong impression on an expectant public ; when Halley's Comet returned again in 1986, many older people's accounts of having seen it in 1910 clearly referred to the Daylight Comet instead.

Release of the film was delayed so it would coincide with the passing of Halley's Comet over the earth in 1986.

Halley's Comet reached perihelion in 1986, and was observed intensively with the IUE, as well as with a large number of other ground-based and satellite missions.

Later on in 1986, one of Carruthers ' inventions captured an ultraviolet image of Halley's Comet.