Who discovered Halley's Comet?
Halley's Comet
Halley's returns to the inner Solar System have been observed and recorded by astronomers since at least 240 BC. Clear records of the comet's appearances were made by Chinese, Babylonian, and medieval European chroniclers, but were not recognized as reappearances of the same object at the time. The comet's periodicity was first determined in 1705 by English astronomer Edmond Halley, after whom it is now named.
Halley's Comet
If, as has been suggested, the reference in the Talmud to "a star which appears once in seventy years that makes the captains of the ships err" (see above) refers to Halley's Comet, it may be a reference to the 66 AD appearance, because this passage is attributed to the Rabbi Yehoshua ben Hananiah. This apparition was the only one to occur during ben Hananiah's lifetime.
Observational history of comets
Since 1985, a total of 8 comets have been visited by spacecrafts. These were the comets Halley, Borrelly, Giacobini–Zinner, Tempel 1, Wild 2, Hartley 2, Grigg–Skjellerup and Churyumov–Gerasimenko, generating a host of new findings. In addition, the spacecraft "Ulysses" unexpectedly traversed the tail of Comet McNaught.
27P/Crommelin
Comet Crommelin, also known as Comet Pons-Coggia-Winnecke-Forbes, is a periodic comet with an orbital period of almost 28 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It is named after the British astronomer Andrew C. D. Crommelin who calculated its orbit in 1930. It is one of only four comets not named after their discoverer(s), the other three being Comets Halley, Encke, and Lexell.
Halley's Comet
The "Giotto" and "Vega" missions gave planetary scientists their first view of Halley's surface and structure. Like all comets, as Halley nears the Sun, its volatile compounds (those with low boiling points, such as water, carbon monoxide, carbon dioxide and other ices) begin to sublime from the surface of its nucleus. This causes the comet to develop a coma, or atmosphere, up to 100,000 km across. Evaporation of this dirty ice releases dust particles, which travel with the gas away from the nucleus. Gas molecules in the coma absorb solar light and then re-radiate it at different wavelengths, a phenomenon known as fluorescence, whereas dust particles scatter the solar light. Both processes are responsible for making the coma visible. As a fraction of the gas molecules in the coma are ionized by the solar ultraviolet radiation, pressure from the solar wind, a stream of charged particles emitted by the Sun, pulls the coma's ions out into a long tail, which may extend more than 100 million kilometres into space. Changes in the flow of the solar wind can cause disconnection events, in which the tail completely breaks off from the nucleus.
Halley's Comet
Halley was the first comet to be recognized as periodic. Until the Renaissance, the philosophical consensus on the nature of comets, promoted by Aristotle, was that they were disturbances in Earth's atmosphere. This idea was disproved in 1577 by Tycho Brahe, who used parallax measurements to show that comets must lie beyond the Moon. Many were still unconvinced that comets orbited the Sun, and assumed instead that they must follow straight paths through the Solar System.
Star of Bethlehem
Other writers suggest that the star was a comet. Halley's Comet was visible in 12 BC and another object, possibly a comet or nova, was seen by Chinese and Korean stargazers in about 5 BC. This object was observed for over seventy days, possibly with no movement recorded. Ancient writers described comets as "hanging over" specific cities, just as the Star of Bethlehem was said to have "stood over" the "place" where Jesus was (the town of Bethlehem). However, this is generally thought unlikely as in ancient times comets were generally seen as bad omens. The comet explanation has been recently promoted by Colin Nicholl. His theory involves a hypothetical comet which could have appeared in 6 BC.
Caroline Herschel
Caroline Lucretia Herschel (; 16 March 1750 – 9 January 1848) was a German astronomer, whose most significant contributions to astronomy were the discoveries of several comets, including the periodic comet 35P/Herschel–Rigollet, which bears her name. She was the younger sister of astronomer William Herschel, with whom she worked throughout her career.
David C. Jewitt
Jewitt is also featured in the 1985 BBC Horizon episode "Halley's Comet: The Apparition" (season 22, episode 17), which documents how — in October 1982 — he was the first to recover the comet before its 1986 visit.
Thomas Bopp
Thomas Joel Bopp (October 15, 1949 – January 5, 2018) was an American amateur astronomer best known as the co-discoverer of comet Hale–Bopp (with Alan Hale) in 1995. At the time of the comet discovery he was a manager at a construction materials factory and an amateur astronomer. On the night of July 22, Bopp was observing the sky with friends in the Arizona desert when he made the discovery. It was the first comet he had observed and he was using a borrowed, home-built telescope. Hale and Bopp both discovered the comet by chance at approximately the same time.
Han dynasty
Han Chinese astronomers made star catalogues and detailed records of comets that appeared in the night sky, including recording the 12 BC appearance of the comet now known as Halley's Comet.
International Halley Watch
Halley's Comet, named after English astronomer Edmund Halley who first demonstrated its periodicity, returns to the vicinity of the Sun and Earth approximately every 76 years. Since comets are believed to be the most primordial objects in the solar system, their study is of great importance to planetary science. At the time of the 1986 return (technically, "apparition") of the comet, astronomical telescopes and related instrumentation were vastly more sensitive than for any previous apparition. Consequently, the International Halley Watch (IHW) was organized to stimulate, standardize, collect, and archive observations of the comet.
Arthur Storer
Arthur Storer (c. 1648 – 1686) was America's first colonial astronomer. He came to Calvert County, Maryland, from Lincolnshire, England. He was among the first observers to sight and record data about a magnificent comet that passed over Patuxent skies in 1682. Storer's work shows up in a number of Newton's writings. The comet became known as Storer's Comet, until Edmund Halley later predicted the comet's return; thereafter this celestial marvel was known as Halley's Comet.
His observations of the great comet of 1680 are mentioned twice in Newton's Philosophiae Naturalis Principia Mathematica.
A planetarium bearing Storer's name is located in Prince Frederick, Maryland.
Gunvalkyrie
The game takes place in an alternate history in 1906 where the British Empire rules all of Earth and several extrasolar colony worlds, powered by technology brought to the planet by Halley's Comet in 1835. An unknown substance known as Halley's Core was found throughout the world, and certain individuals who came in contact with it and gained superhuman abilities became known as "Halley's Chosen." The first of these was a scientist named Dr. Hebble Gate, who was affected by the comet while in his mother's womb. With his superhuman mind he harnessed the power of Halley's Core and discovered a wide range of scientific breakthroughs, including fusion and nuclear power, genetic engineering, computers, space travel and countless others. With these technologies the British Empire quickly conquered the earth, and Gate is famous as the man responsible. A complete mystery to all, Gate also holds great power over economic, political and military affairs, and is the founder of the Hebble Foundation and the GunValkyrie (GV) Organization, composed of Halley's Chosen throughout the world to prevent the misuse of technology. He suddenly disappears, throwing the world into shock, and has been missing for four years by the time the game begins.
Halley's Comet
The 1910 visitation is also recorded as being the travelling companion of Hedley Churchward, the first known English Muslim to make the Haj pilgrimage to Mecca. However, his explanation of its scientific predictability did not meet with favour in the Holy City.
11132 Horne
Horne is also a contributing editor for "Sky & Telescope" magazine and has served as a study leader for S&T astronomical expeditions to Mexico, Africa, the Caribbean and Iceland. He photographed Halley's Comet from the Australian Outback in 1986 and his astronomical photographs have appeared in magazines and newspapers worldwide. He regularly reviews amateur astronomy products for Sky and Telescope¹s test reports. During 2002, Horne produced a collection of his astronomical photographs over 25 years. That "Backyard Universe Gallery collection" was displayed at the Morehead Planetarium and Science Center in Chapel Hill, North Carolina, 40 years after a class visit there had triggered Horne's lifelong interest in astronomy.
David Kennedy (astronomer)
In 1910 together with two seminarians, Joseph Cullen and Ignatius von Gottfried, he photographed Halley's Comet. The photographs of this period were the best in the world for that appearance of the comet, and were republished in the United States by NASA in 1986.
Halley's Comet
During its 1986 apparition, Halley's Comet became the first comet to be observed in detail by spacecraft, providing the first observational data on the structure of a comet nucleus and the mechanism of coma and tail formation. These observations supported a number of longstanding hypotheses about comet construction, particularly Fred Whipple's "dirty snowball" model, which correctly predicted that Halley would be composed of a mixture of volatile ices—such as water, carbon dioxide, and ammonia—and dust. The missions also provided data that substantially reformed and reconfigured these ideas; for instance, it is now understood that the surface of Halley is largely composed of dusty, non-volatile materials, and that only a small portion of it is icy.
Halley's Comet
Halley's prediction of the comet's return proved to be correct, although it was not seen until 25 December 1758, by Johann Georg Palitzsch, a German farmer and amateur astronomer. It did not pass through its perihelion until 13 March 1759, the attraction of Jupiter and Saturn having caused a retardation of 618 days. This effect was computed prior to its return (with a one-month error to 13 April) by a team of three French mathematicians, Alexis Clairaut, Joseph Lalande, and Nicole-Reine Lepaute. The confirmation of the comet's return was the first time anything other than planets had been shown to orbit the Sun. It was also one of the earliest successful tests of Newtonian physics, and a clear demonstration of its explanatory power. The comet was first named in Halley's honour by French astronomer Nicolas-Louis de Lacaille in 1759.
Observational history of comets
As early as the 18th century, some scientists had made correct hypotheses as to comets' physical composition. In 1755, Immanuel Kant hypothesized that comets are composed of some volatile substance, whose vaporization gives rise to their brilliant displays near perihelion. In 1836, the German mathematician Friedrich Wilhelm Bessel, after observing streams of vapor during the appearance of Halley's Comet in 1835, proposed that the jet forces of evaporating material could be great enough to significantly alter a comet's orbit, and he argued that the non-gravitational movements of Encke's Comet resulted from this phenomenon.
Halley's Comet
"Giotto" provided the first evidence in support of Fred Whipple's "dirty snowball" hypothesis for comet construction; Whipple postulated that comets are icy objects warmed by the Sun as they approach the inner Solar System, causing ices on their surfaces to sublimate (change directly from a solid to a gas), and jets of volatile material to burst outward, creating the coma. "Giotto" showed that this model was broadly correct, though with modifications. Halley's albedo, for instance, is about 4%, meaning that it reflects only 4% of the sunlight hitting it; about what one would expect for coal. Thus, despite appearing brilliant white to observers on Earth, Halley's Comet is in fact pitch black. The surface temperature of evaporating "dirty ice" ranges from at higher albedo to at low albedo; Vega 1 found Halley's surface temperature to be in the range . This suggested that only 10% of Halley's surface was active, and that large portions of it were coated in a layer of dark dust that retained heat. Together, these observations suggested that Halley was in fact predominantly composed of non-volatile materials, and thus more closely resembled a "snowy dirtball" than a "dirty snowball".
Halley's Comet
The 141 AD apparition was recorded in Chinese chronicles. It was also recorded in the Tamil work "Purananuru", in connection with the death of the south Indian Chera king Yanaikatchai Mantaran Cheral Irumporai.
Crab Nebula
The Crab Nebula was first identified in 1731 by John Bevis. The nebula was independently rediscovered in 1758 by Charles Messier as he was observing a bright comet. Messier catalogued it as the first entry in his catalogue of comet-like objects; in 1757, Alexis Clairaut reexamined the calculations of Edmund Halley and predicted the return of Halley's Comet in late 1758. The exact time of the comet's return required the consideration of perturbations to its orbit caused by planets in the Solar System such as Jupiter, which Clairaut and his two colleagues Jérôme Lalande and Nicole-Reine Lepaute carried out more precisely than Halley, finding that the comet should appear in the constellation of Taurus. It is in searching in vain for the comet that Charles Messier found the Crab nebula, which he at first thought to be Halley's comet. After some observation, noticing that the object that he was observing was not moving across the sky, Messier concluded that the object was not a comet. Messier then realised the usefulness of compiling a catalogue of celestial objects of a cloudy nature, but fixed in the sky, to avoid incorrectly cataloguing them as comets.
Comet
In 1950, Fred Lawrence Whipple proposed that rather than being rocky objects containing some ice, comets were icy objects containing some dust and rock. This "dirty snowball" model soon became accepted and appeared to be supported by the observations of an armada of spacecraft (including the European Space Agency's "Giotto" probe and the Soviet Union's "Vega 1" and "Vega 2") that flew through the coma of Halley's Comet in 1986, photographed the nucleus, and observed jets of evaporating material.
Comet Chasers
The episode begins with Alan Tracy talking about flying to Halley's Comet in his sleep. He is then woken up by Scott Tracy and Grandma Tracy. Grandma informs him about a broadcast to do with Halley's comet. Alan starts to state facts about the comet which he already has done multiple times according to Scott. The broadcast begins with Francois Lemaire and his wife visiting the comet where he decides to go inside the comet's tail. Scott yells at the broadcast about it being a bad idea, John Tracy pops up stating that they have a situation.
Thomas John Hussey
Hussey achieved some contemporary celebrity as being one of the first people in Britain (along with Sir James South) to see the return of Halley's Comet on 22 August 1835, communicating his subsequent observations with enthusiasm. At the time, Hussey was engaged in publishing a "Catalogue of Comets" in a series of papers for the Philosophical Magazine.
Halley's Comet
Halley may have been recorded as early as 467 BC, but this is uncertain. A comet was recorded in ancient Greece between 468 and 466 BC; its timing, location, duration, and associated meteor shower all suggest it was Halley. According to Pliny the Elder, that same year a meteorite fell in the town of Aegospotami, in Thrace. He described it as brown in colour and the size of a wagon load. Chinese chroniclers also mention a comet in that year.
Nicole-Reine Lepaute
Nicole-Reine Lepaute (née Étable de la Briere; also known as Hartense Lepaute or Hortense Lepaute), (5 January 1723 – 6 December 1788) was a French astronomer and mathematician. She predicted the return of Halley's Comet, calculated the timing of a solar eclipse and constructed a group of catalogs for the stars. She was also a member of the Scientific Academy of Béziers.
Halley's Comet
Two Space Shuttle missions—the ill-fated STS-51-L (ended by the "Challenger" disaster) and STS-61-E—were scheduled to observe Halley's Comet from low Earth orbit. STS-51-L carried the Shuttle-Pointed Tool for Astronomy (SPARTAN-203) satellite, also called the Halley's Comet Experiment Deployable (HCED). STS-61-E was a "Columbia" mission scheduled for March 1986, carrying the ASTRO-1 platform to study the comet. Due to the suspension of America's manned space program after the "Challenger" explosion, the mission was canceled, and ASTRO-1 would not fly until late 1990 on STS-35.
Johann Georg Palitzsch
Johann Georg Palitzsch (11 June 1723 – 21 February 1788) was a German astronomer who became famous for recovering Comet 1P/Halley (better known as Halley's Comet) on Christmas Day, 1758. The periodic nature of this comet had been deduced by its namesake Edmond Halley in 1705, but Halley had died before seeing if his prediction would come true.
Raised to become a successful farmer under a strict stepfather, Palitzsch secretly studied as much astronomy as he could from the books he could afford. He learned contemporary astronomy from the book “Vorhof der Sternwissenschaft” (“The Forecourt of Astronomy”) by Christian Pescheck. He learned Latin and, at age 21, inherited the farm, which allowed him to construct his own botanical garden, library, laboratory, and museum.
He received support from various benefactors, including the future King. But the wars between Prussia and Austria interrupted his ambitions.
Hermann Hunger
Hunger translated a cuneiform tablet from the Babylonian astronomical diaries that describes the appearance of Halley's Comet in 163 BCE.
Halley's Comet Opal
The Halley's Comet Opal is the largest uncut black opal in the world, according to the Guinness Book of World Records. It is so named because it was unearthed in 1986, a year when Halley's Comet could be seen from Earth. It is the third largest gem grade black opal ever recorded, the largest one extant, and the largest specimen ever found in its region. It was found at Lightning Ridge, New South Wales, Australia by the Lunatic Hill Mining Syndicate. It weighs (13.99 ounces) and is about the size of a man's fist. The Halley's Comet Opal is a very fine specimen, with few flaws or blemishes and a large green and orange thick color bar which goes through the opal. Formed about 20 million years ago, it is an example of a nobby, which is a natural lump-shaped opal found only at Lightning Ridge. As of 2006 it was for sale at $1.2 million.
Historical comet observations in China
Chinese observations of Halley's Comet are of especial importance to astronomers because of the important place this comet had in their growing understanding of them. The earliest confirmed sighting was in 240 BC (in the "Records of the Grand Historian")—with a continuous record after 164 BC. A comet observed in 467 BC may have been Halley, but there is insufficient information to be sure. The most accurate records of Halley begin in 12 BC.
Halley's Comet
Halley's apparition of 1456 was also witnessed in Kashmir and depicted in great detail by Śrīvara, a Sanskrit poet and biographer to the Sultans of Kashmir. He read the apparition as a cometary portent of doom foreshadowing the imminent fall of Sultan Zayn al-Abidin (AD 1418/1420–1470).
William Pearson (astronomer)
Pearson observed Halley's comet on 29 October 1835, and in 1839 he deduced a value for the obliquity of the ecliptic from his own research.
Halley's Comet
The 1145 apparition was recorded by the monk Eadwine. The 1986 apparition exhibited a fan tail similar to Eadwine's drawing. Some claim that Genghis Khan was inspired to turn his conquests toward Europe by the 1222 apparition. The 1301 apparition may have been seen by the artist Giotto di Bondone, who represented the Star of Bethlehem as a fire-colored comet in the Nativity section of his Arena Chapel cycle, completed in 1305. Its 1378 appearance is recorded in the "Annales Mediolanenses" as well as in East Asian sources.
Nicole-Reine Lepaute
Jérôme Lalande recommended her along with the mathematician Alexis Clairault to calculate the predicted return of Halley's Comet, as well as to calculate the attraction of Jupiter and Saturn of the Halley's comet. The team worked on the calculations for more than six months straight, barely stopping for food. In November 1758, the team presented their conclusion that the comet would arrive on 13 April 1759. They were almost correct, as the comet arrived on 13 March 1759. As a result of their calculations, this was the first time scientists had successfully predicted when the comet would cross the perihelion, i.e. the point of the comet orbit closest to the Sun. Clairault did not recognize her work at all in his work, which upset Lalande who considered Lepaute the "most distinguished female French astronomer ever." Jérôme Lalande acknowledged her help in an article.
Halley's Comet
After witnessing a bright light in the sky which most historians have identified as Halley's Comet, Zara Yaqob, Emperor of Ethiopia from 1434 to 1468, founded the city of Debre Berhan (tr. City of Light) and made it his capital for the remainder of his reign.
C/1911 S3
Comet Beljawsky is also known as 1911 IV and 1911g according to the naming conventions at the time. The comet was discovered by the Russian astronomer Sergei Ivanovich Beljawsky September 29, 1911 and shortly thereafter it was independently seen by four or five other observers in the United States and probably by others throughout the world. At the time it was discovered, the comet was near to the Sun which made observations difficult. However, several days after discovery it was a naked eye object for a few days in the morning sky and later, after perihelion, as an evening object. It faded rapidly, becoming visible only in telescopes and was last seen on February 17, 1912. The comet sported a tail 8 to 10 degrees in length. In mid-October it was visible in the evening sky at the same time as another bright comet, C/1911 O1 Brooks.
Sydney Observatory
An early observatory was established in 1788 on Dawes Point, at the foot of Observatory Hill, in an ultimately unsuccessful attempt to observe in 1790 the return of a comet suggested by Edmond Halley of Halley's Comet fame.
Halley's Comet
The apparition of 87 BC was recorded in Babylonian tablets which state that the comet was seen "day beyond day" for a month. This appearance may be recalled in the representation of Tigranes the Great, an Armenian king who is depicted on coins with a crown that features, according to Vahe Gurzadyan and R. Vardanyan, "a star with a curved tail [that] may represent the passage of Halley's Comet in 87 BC." Gurzadyan and Vardanyan argue that "Tigranes could have seen Halley's Comet when it passed closest to the Sun on August 6 in 87 BC" 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.
Edmond Halley
From an observatory he constructed on Saint Helena, Halley recorded a transit of Mercury across the Sun. He realised a similar transit of Venus could be used to determine the size of the Solar System. He also used his observations to expand contemporary star maps. He aided in observationally proving Isaac Newton's laws of motion, and funded the publication of Newton's influential "Philosophiæ Naturalis Principia Mathematica".
From his September 1682 observations, he used the laws of motion to compute the periodicity of Halley's Comet in his 1705 "Synopsis of the Astronomy of Comets". It was named after him upon its predicted return in 1758, which he did not live to see.
Comet
A comet may be discovered photographically using a wide-field telescope or visually with binoculars. However, even without access to optical equipment, it is still possible for the amateur astronomer to discover a sungrazing comet online by downloading images accumulated by some satellite observatories such as SOHO. SOHO's 2000th comet was discovered by Polish amateur astronomer Michał Kusiak on 26 December 2010 and both discoverers of Hale-Bopp used amateur equipment (although Hale was not an amateur).
Hills cloud
Comet McNaught, discovered on 7 August 2006 in Australia by Robert H. McNaught, became one of the brightest comets of recent decades, with an aphelion of 4,100 AU. Finally, one of the farthest-known comets is Comet West, discovered by Danish astronomer Richard Martin West at the La Silla Observatory in Chile on 10 August 1975; it reaches 13,560 AU.
Christian Gärtner
In December 1758 (simultaneously with Johann Georg Palitzsch) Gärtner observed the return of Halley's Comet, predicted by Edmond Halley in 1705.
Halley's Comet
Researchers in 1981 attempting to calculate the past orbits of Halley by numerical integration starting from accurate observations in the seventeenth and eighteenth centuries could not produce accurate results further back than 837 due to a close approach to Earth in that year. It was necessary to use ancient Chinese comet observations to constrain their calculations.
Alan Hale (astronomer)
Comet Hale–Bopp, originally labeled C/1995 O1, and sometimes called "the Great Comet of 1997", became one of the most-viewed comets in human history, and the brightest comet seen since Comet West in 1976, appearing 1000 times brighter than Comet Halley did at the same distance.
Observational history of comets
By the middle of the twentieth century, this model suffered from a number of shortcomings: in particular, it failed to explain how a body that contained only a little ice could continue to put on a brilliant display of evaporating vapor after several perihelion passages. In 1950, Fred Lawrence Whipple proposed that rather than being rocky objects containing some ice, comets were icy objects containing some dust and rock. This "dirty snowball" model soon became accepted and appeared to be supported by the observations of an armada of spacecraft (including the European Space Agency's "Giotto" probe and the Soviet Union's "Vega 1" and "Vega 2") that flew through the coma of Halley's Comet in 1986, photographed the nucleus, and observed jets of evaporating material.
Halley's Comet
Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and the only naked-eye comet that might appear twice in a human lifetime. Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061.
Halley's Comet
American satirist and writer Mark Twain was born on 30 November 1835, exactly two weeks after the comet's perihelion. In his autobiography, published in 1909, he said,
Comet Encke
As its official designation implies, Encke's Comet was the first periodic comet discovered after Halley's Comet (designated 1P/Halley). It was independently observed by several astronomers, the second being Caroline Herschel in 1795 and the third Jean-Louis Pons in 1818. Its orbit was calculated by Johann Franz Encke, who through laborious calculations was able to link observations of comets in 1786 (designated 2P/1786 B1), 1795 (2P/1795 V1), 1805 (2P/1805 U1) and 1818 (2P/1818 W1) to the same object. In 1819 he published his conclusions in the journal "Correspondance astronomique", and predicted correctly its return in 1822 (2P/1822 L1). It was recovered by Carl Ludwig Christian Rümker at Parramatta Observatory on 2 June 1822.
Edmond Halley
In 1676, Halley visited the south Atlantic island of Saint Helena and set up an observatory with a large sextant with telescopic sights to catalogue the stars of the Southern Hemisphere. While there he observed a transit of Mercury across the Sun, and realised that a similar transit of Venus could be used to determine the absolute size of the Solar System. He returned to England in May 1678. In the following year he went to Danzig (Gdańsk) on behalf of the Royal Society to help resolve a dispute. Because astronomer Johannes Hevelius did not use a telescope, his observations had been questioned by Robert Hooke. Halley stayed with Hevelius and he observed and verified the quality of Hevelius' observations. In 1679, Halley published the results from his observations on St. Helena as "Catalogus Stellarum Australium" which included details of 341 southern stars. These additions to contemporary star maps earned him comparison with Tycho Brahe: e.g. "the southern Tycho" as described by Flamsteed. Halley was awarded his M.A. degree at Oxford and elected as a Fellow of the Royal Society at the age of 22. In September 1682 he carried out a series of observations of what became known as Halley's Comet, though his name became associated with it because of his work on its orbit and predicting its return in 1758 (which he did not live to see).
In 1686, Halley published the second part of the results from his Helenian expedition, being a paper and chart on trade winds and monsoons. The symbols he used to represent trailing winds still exist in most modern day weather chart representations. In this article he identified solar heating as the cause of atmospheric motions. He also established the relationship between barometric pressure and height above sea level. His charts were an important contribution to the emerging field of information visualisation.
C/1760 A1
Messier came up against opposition from Navy astronomer Joseph Nicholas Delisle, who had employed Messier from October 1751, because Delisle would not publish the discovery Messier had made. This was a continuation of the mistrust that had developed between Messier and Delisle because Delisle had been slow to publish work done by Messier in 1759; Messier had independently rediscovered Halley's Comet on 21 January 1759 but because Messier had doubted the correctness of Delisle's path, Delisle instructed Messier to continue observing the comet and refused to announce his discovery. Delisle apparently later changed his mind and announced the discovery on 1 April 1759, but other French astronomers discredited Delisle's claim, labelling the discovery an April Fools' joke. Delisle retired in 1760.
Heart of the Comet
Heart of the Comet is a novel by David Brin and Gregory Benford about human space travel to Halley's Comet published in 1986. Its publication coincided with the comet's 1986 approach to the Earth.
Great comet
A great comet is a comet that becomes exceptionally bright. There is no official definition; often the term is attached to comets such as Halley's Comet, which are bright enough to be noticed by casual observers who are not looking for them, and become well known outside the astronomical community. Great comets are rare; on average, only one will appear in a decade. Although comets are officially named after their discoverers, great comets are sometimes also referred to by the year in which they appeared great, using the formulation "The Great Comet of ...", followed by the year.
Friedrich Bessel
Bessel came to the attention of a major figure of German astronomy at the time, Heinrich Wilhelm Olbers, by producing a refinement on the orbital calculations for Halley's Comet in 1804, using old observation data taken from Thomas Harriot and Nathaniel Torporley in 1607.
103P/Hartley
Comet Hartley 2 is a small Jupiter-family comet having an orbital period of 6.46 years. It was discovered by Malcolm Hartley in 1986 at the Schmidt Telescope Unit, Siding Spring Observatory, Australia. It has the perihelion near the Earth's orbit at 1.05 AU from the Sun.
Giovanni Battista Audiffredi
The predicted reappearance in the middle of the century of Halley's comet intensified scientific interest in cometic orbits. The epoch was favored with a number of brilliant objects of this kind, and that of 1769 distinguished itself by its great nucleus and by the tail which stretched over more than half the sky. Audiffredi took observations of the positions of the comet and published his results under the title, "Dimostrazione della stazione della cometa, 1769" (1770).
Observational history of comets
Ancient Chinese records of comet apparitions have been particularly useful to modern astronomers. They are accurate, extensive, and consistent over three millennia. The past orbits of many comets have been calculated entirely from these records and most notably they were used in connection with Halley's comet.
Comet nucleus
About 80% of the Halley's Comet nucleus is water ice, and frozen carbon monoxide (CO) makes up another 15%. Much of the remainder is frozen carbon dioxide, methane, and ammonia. Scientists think that other comets are chemically similar to Halley's Comet. The nucleus of Halley's Comet is also an extremely dark black. Scientists think that the surface of the comet, and perhaps most other comets, is covered with a black crust of dust and rock that covers most of the ice. These comets release gas only when holes in this crust rotate toward the Sun, exposing the interior ice to the warming sunlight.
Halley's Comet
Halley is classified as a "periodic" or "short-period comet"; one with an orbit lasting 200 years or less. This contrasts it with long-period comets, whose orbits last for thousands of years. Periodic comets have an average inclination to the ecliptic of only ten degrees, and an orbital period of just 6.5 years, so Halley's orbit is atypical. Most short-period comets (those with orbital periods shorter than 20 years and inclinations of 20–30 degrees or less) are called Jupiter-family comets. Those resembling Halley, with orbital periods of between 20 and 200 years and inclinations extending from zero to more than 90 degrees, are called Halley-type comets. , only 75 Halley-type comets have been observed, compared with 511 identified Jupiter-family comets.
23P/Brorsen–Metcalf
23P/Brorsen–Metcalf is a periodic comet with an orbital period of 70 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It was first discovered by Theodor Brorsen at the Altona Observatory on July 20, 1847, and again by Kaspar Schweizer (Moscow) on August 11, 1847. It was predicted that it would reappear between 1919 and 1922.
Caroline Herschel
During 1786–97 she discovered eight comets, the first on 1 August 1786. She had unquestioned priority as discoverer of five of the comets and rediscovered Comet Encke in 1795. Five of her comets were published in Philosophical Transactions. A packet of paper bearing the superscription, "This is what I call the Bills and Receipts of my Comets" contains some data connected with the discovery of each of these objects. William was summoned to Windsor Castle to demonstrate Caroline's comet to the royal family. William recorded this phenomenon, himself, terming it "My Sister's Comet." Caroline Herschel is often credited as the first woman to discover a comet; however, Maria Kirch discovered a comet in the early 1700s, but is often overlooked because at the time, the discovery was attributed to her husband, Gottfried Kirch.
Great comet
For a comet to become spectacular, it also needs to pass close to the Earth if it is to be easily seen. 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 comet became visible to the naked eye, but was unspectacular. On the other hand, the intrinsically small and faint Comet Hyakutake (C/1996 B2) appeared very bright and spectacular due to its very close approach to Earth at its nearest during March 1996. Its passage near the Earth was one of the closest cometary approaches on record.
Biela's Comet
It was Wilhelm von Biela, an army officer serving at the fortress town of Josefstadt, who observed the comet during its 1826 perihelion approach (on February 27) and calculated its orbit, discovering it to be periodic with a period of 6.6 years. At the time it was only the third comet known to be periodic, after comets Halley and Encke. The comet was named after Biela, although there was initially some controversy due to a later but independent discovery by Jean-Félix Adolphe Gambart, who also provided the first mathematical proof linking the 1826 and 1805 comets (letters from Biela and Gambart were published in the same issue of the "Astronomische Nachrichten"). A third claim was made by Thomas Clausen, who had independently linked the comets.
Comet Holmes
The comet's discovery was confirmed by Edward Walter Maunder (Royal Observatory, Greenwich, England), William Henry Maw (Kensington, London, England), 
and B. Kidd (Bramley, Surrey, England).
Independent discoveries were made by Thomas David Anderson (Edinburgh, Scotland) on November 8 and by Mike Brown (Wilkes, USA) and by John Ewen Davidson (Mackay, Queensland, Australia) on November 9.
Graciano Ricalde Gamboa
He achieved recognition for having calculated in 1910 the orbit dish of Halley's Comet. In 1923 he precisely calculated the eclipse sun that year, and became part of the Mexican Geodetic Commission who observed and studied in Champotón in the state of Campeche.
Edmond Halley
In November 1703, Halley was appointed Savilian Professor of Geometry at the University of Oxford, his theological enemies, John Tillotson and Bishop Stillingfleet having died, and received an honorary degree of doctor of laws in 1710. In 1705, applying historical astronomy methods, he published "Synopsis Astronomia Cometicae", which stated his belief that the comet sightings of 1456, 1531, 1607, and 1682 were of the same comet, which he predicted would return in 1758. Halley did not live to witness the comet's return, but when it did, the comet became generally known as Halley's Comet.
Malcolm Hartley
He's best known for his discovery and co-discovery of 10 comets since the 1980s, among them
79P/du Toit-Hartley, 80P/Peters–Hartley, 100P/Hartley, 110P/Hartley, and C/1984 W2. Unfortunately for Hartley, in 2002, "the Anglo-Australian Observatory retrofitted its Schmidt to perform multi-object spectroscopy, essentially halting all astrophotography with the telescope and ending any future possibility for comet discovery". In November 2010, he visited NASA's Jet Propulsion Laboratory facility in California to witness the "EPOXI" mission flyby of comet 103P/Hartley on 4 November 2010.
Pope Callixtus III
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 appearance 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. No known primary source supports the authenticity of this account. The 29 June 1456 papal bull of Callixtus III calling for a public prayer for the success of the crusade makes no mention of the comet. By 6 August, when the Turkish siege was broken, the comet had not been visible in either Europe or Turkey for several weeks.
Astron (spacecraft)
Among the most important observations by Astron were those of the SN 1987A supernova on March 4–12, 1987 and of Halley's Comet in December, 1985, that allowed a group of Soviet scientists to develop a model of the coma surrounding Halley's Comet.
Timeline of astronomy
The returning Halley's comet is met by a fleet of five probes from Russia, Japan, and Europe. The most ambitious is the European Space Agency's Giotto spacecraft, which flies through the comet's coma and photographs the nucleus.
Denison Olmsted
In 1825, he became professor of mathematics and natural philosophy at Yale. He published an elaborate theory of hail-stones in 1830, which caused much discussion, but finally received the general approbation of meteorologists. The shower of shooting stars that fell in November 1833 attracted his attention, and he studied their history and behavior until he was able satisfactorily to demonstrate their cosmical origin. Olmsted appears to have been the earliest person to use the word radiator to mean a heating appliance in a patent of 1834 when he wrote that it was "a peculiar kind of apparatus, which I call a radiator". Olmsted and his associate, Elias Loomis, were in 1835 the first American investigators to observe the Halley's Comet.
Near-Earth object
The first near-Earth objects to be observed by humans were comets. Their extraterrestrial nature was recognised and confirmed only after Tycho Brahe tried to measure the distance of a comet through its parallax in 1577; and the periodicity of some comets was recognised in 1705, when Edmond Halley first published his orbit calculations for the returning object now known as Halley's Comet. The 1758–1759 return of Halley's Comet was the first comet appearance predicted in advance.
William Henry Finlay
William Henry Finlay (born 17 June 1849 in Liverpool; died 7 December 1924 in Cape Town, South Africa) was a South African astronomer. He was First Assistant at the Cape Observatory from 1873 to 1898 under Edward James Stone. He discovered the periodic comet 15P/Finlay. Earlier, he was one of the first to spot the "Great Comet of 1882" (C/1882 R1). The first telegraphic determinations of longitude along the western coast of Africa were made by Finlay and T. F. Pullen.
Halley's Comet
On 12 February 1991, at a distance of from the Sun, Halley displayed an outburst that lasted for several months, releasing a cloud of dust 300,000 km across. The outburst likely started in December 1990, and then the comet brightened from magnitude 24.3 to magnitude 18.9. Halley was most recently observed in 2003 by three of the Very Large Telescopes at Paranal, Chile, when Halley's magnitude was 28.2. The telescopes observed Halley, at the faintest and farthest any comet has ever been imaged, in order to verify a method for finding very faint trans-Neptunian objects. Astronomers are now able to observe the comet at any point in its orbit.
Halley (song)
The song is in praise of the famous Halley comet and the band's joy with it, with the objective to give a good new, Halley comet could be seen in Earth. This comet only can be seen from Earth every 76 years, and could be seen in 1986, named after the astronomer Edmond Halley.
Khagol Mandal
The organization was founded a few years before the arrival of the Halley's comet and succeeded in its intent to generate curiosity among the general public about the comet.
Comet Hale–Bopp
Carolyn Shoemaker and her husband Gene, both famous for co-discovering comet Shoemaker–Levy 9, were involved in a car crash after photographing the comet. Gene died in the crash and his ashes were sent to the Moon aboard NASA's "Lunar Prospector" mission along with an image of Hale–Bopp, "the last comet that the Shoemakers observed together".
35P/Herschel–Rigollet
35P/Herschel–Rigollet is a periodic comet with an orbital period of 155 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It was discovered by Caroline Herschel (Slough, United Kingdom) on 1788-12-21. Given that the comet takes 155 years to orbit the Sun, predictions for the next perihelion passage in 2092 vary by about a month.
Halley's Comet
This appearance of the comet is also noted in the "Anglo-Saxon Chronicle". Eilmer of Malmesbury may have seen Halley previously in 989, as he wrote of it in 1066: "You've come, have you? ... You've come, you source of tears to many mothers, you evil. I hate you! It is long since I saw you; but as I see you now you are much more terrible, for I see you brandishing the downfall of my country. I hate you!"
Halley's Comet
Halley's Comet is visible from Earth every 74–79 years.
Radha Gobinda Chandra
In the year of 1910 (April–July), Chandra observed the Halley's Comet from Jessore with his small binocular as he did not have any powerful binocular or other helping tool. He wrote the details information of his observation in the 'Hindu Magazine' of that time.
Space Place at Carter Observatory
After Crossley’s death in 1905, the telescope was purchased by Reverend Dr David Kennedy and shipped to New Zealand, where it was installed at the Meeanee Observatory at the Marist Seminary near Napier. Kennedy used the telescope to take photographs of Halley’s Comet during its 1910 approach.
List of comets by type
Comets with a period between 20 and 200 years, named after the first identified member, Halley's Comet. These comets orbit between the orbit of Jupiter and Pluto, and are thought to be long-period comets that slowly migrated inwards, or Jupiter family comets that had been slingshotted outwards by Jupiter's gravity
Orionids
Meteor showers first designated "shooting stars" were connected to comets in the 1800s. E.C. Herrick made an observation in 1839 and 1840 about the activity present in the October night skies. A. S. Herschel produced the first documented record that gave accurate forecasts for the next meteor shower. The Orionid meteor shower is produced by the well known Halley's Comet, which was named after the astronomer Edmund Halley and last passed through the inner solar system in 1986 on its 75- to 76-year orbit. When the comet passes through the solar system, the sun sublimates some of the ice, allowing rock particles to break away from the comet. These particles continue on the comet's trajectory and appear as meteors ("falling stars") when they pass through Earth's upper atmosphere. Halley's comet is also responsible for creating the Eta Aquariids, which occur each May.
Halley's Comet
Halley's orbital period has varied between 74–79 years since 240 BC. Its orbit around the Sun is highly elliptical, with an orbital eccentricity of 0.967 (with 0 being a circle and 1 being a parabolic trajectory). The perihelion, the point in the comet's orbit when it is nearest the Sun, is just 0.6 AU. This is between the orbits of Mercury and Venus. Its aphelion, or farthest distance from the Sun, is 35 AU (roughly the distance of Pluto). Unusual 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. The orbit is inclined by 18° to the ecliptic, with much of it lying south of the ecliptic. (Because it is retrograde, the true inclination is 162°.) Due to the retrograde orbit, it has one of the highest velocities relative to the Earth of any object in the Solar System. The 1910 passage was at a relative velocity of 70.56 km/s (157,838 mph or 254,016 km/h). Because its orbit comes close to Earth's in two places, Halley is associated with two meteor showers: the Eta Aquariids in early May, and the Orionids in late October. Halley is the parent body to the Orionids. Observations conducted around the time of Halley's appearance in 1986 suggested that the comet could additionally perturb the Eta Aquariids meteor shower, although it might not be the parent of that shower.
Halley's Comet
Halley is the most active of all the periodic comets, with others, such as Comet Encke and Comet Holmes, being one or two orders of magnitude less active. Its day side (the side facing the Sun) is far more active than the night side. Spacecraft observations showed that the gases ejected from the nucleus were 80% water vapour, 17% carbon monoxide and 3–4% carbon dioxide, with traces of hydrocarbons although more-recent sources give a value of 10% for carbon monoxide and also include traces of methane and ammonia. The dust particles were found to be primarily a mixture of carbon–hydrogen–oxygen–nitrogen (CHON) compounds common in the outer Solar System, and silicates, such as are found in terrestrial rocks. The dust particles decreased in size down to the limits of detection (~0.001 µm). The ratio of deuterium to hydrogen in the water released by Halley was initially thought to be similar to that found in Earth's ocean water, suggesting that Halley-type comets may have delivered water to Earth in the distant past. Subsequent observations showed Halley's deuterium ratio to be far higher than that found in Earth's oceans, making such comets unlikely sources for Earth's water.
Eleanor F. Helin
Helin is a prolific discoverer of minor planets "(see list)" and several comets, including periodic comets 111P/Helin–Roman–Crockett, 117P/Helin–Roman–Alu and 132P/Helin–Roman–Alu. She is credited as the discoverer of the object now known as both asteroid 4015 Wilson–Harrington and comet 107P/Wilson–Harrington. Although Wilson and Harrington preceded her by some decades, their observations did not establish an orbit for the object, while her rediscovery did.
Comets in fiction
Comets have, through the centuries, appeared in numerous works of fiction. In earliest times they were seen as portents, either of disaster or of some great historical change. As knowledge of comets increased, comets came to be imagined not just as symbols, but as powerful forces in their own right, capable of causing disaster. More recently, comets have been described as destinations for space travelers.
As the first-discovered periodic comet, and the best known by name, Halley's Comet has a prominent place in fiction.
Hervé Faye
He studied comets, and discovered the periodic comet 4P/Faye on 22 November 1843. His discovery of "Faye's Comet" attracted worldwide attention, and won him the 1844 Lalande Prize and a membership in the French Academy of Sciences. In 1848 he became an instructor in geodesy at the Polytechnique, and in 1854 rector of the academy at Nancy and professor of astronomy in the faculty of science there. Other promotions followed in succeeding decades. He became Minister of Public Instruction in the Rochebouet cabinet in 1877, a position which he held only briefly.
Hills cloud
Some famous comets reach great distances and are candidates for Hills cloud objects. For example, Comet Lovejoy, discovered on 15 March 2007 by Australian astronomer Terry Lovejoy, reached an aphelion distance of 2,850 AU. Comet Hyakutake, discovered in 1996 by amateur astronomer Yuji Hyakutake, has an aphelion of 3,410 AU. Comet Machholz, discovered on 27 August 2004 by amateur astronomer Donald Machholz, goes even further, to 4,787 AU.
Daniel du Toit
All comets were discovered whilst examining photographic plates taken by the Bache or Metcalf telescopes. It was their job to check the photographic plates taken on behalf of Harlow Shapley, then Director at Harvard. The exposures were generally 45 minutes on Cramer High Speed Blue plates, or later Kodak 103a, taken with the 10-inch Metcalf or 8-inch Bache telescopes.
It was during the examination of the exposure for image quality that Daniel du Toit discovered his comets.
Daniel du toit and his colleague Michiel Bester discovered several comets, with Michiel Bester ranked first with 6 comets discovered, and Daniel discovering 5 comets and dr J.S. Paraskevopoulos discovering 2 this gives the Boyden Observatory a total of 13 comets discovered.
Messier 13
M13 was discovered by Edmond Halley in 1714, and cataloged by Charles Messier on June 1, 1764 into his list of objects not to mistake for comets; Messier's list, including Messier 13, eventually became known as the Messier Catalog.
Comet Encke
Comet Encke or Encke's Comet (official designation: 2P/Encke) is a periodic comet that completes an orbit of the Sun once every 3.3 years. (This is the shortest period of a reasonably bright comet; the faint main-belt comet 311P/PANSTARRS has a period of 3.2 years.) Encke was first recorded by Pierre Méchain in 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke; like Halley's Comet, it is unusual in being named after the calculator of its orbit rather than its discoverer. Like most comets, it has a very low albedo, reflecting only 4.6% of the light it receives. The diameter of the nucleus of Encke's Comet is 4.8 km.
Comet nucleus
During a flyby in September 2001, the Deep Space 1 spacecraft observed the nucleus of Comet Borrelly and found it to be about half the size (8×4×4 km) of the nucleus of Halley's Comet. Borrelly's nucleus was also potato-shaped and had a dark black surface. Like Halley's Comet, Comet Borrelly only released gas from small areas where holes in the crust exposed the ice to sunlight.
The nucleus of comet Hale–Bopp was estimated to be 60 ± 20 km in diameter. Hale-Bopp appeared bright to the unaided eye because its unusually large nucleus gave off a great deal of dust and gas.
Halley's Comet
In 1989, Boris Chirikov and Vitaly Vecheslavov performed an analysis of 46 apparitions of Halley's Comet taken from historical records and computer simulations. These studies showed that its dynamics were chaotic and unpredictable on long timescales. Halley's projected lifetime could be as long as 10 million years. These studies also showed that many physical properties of Halley's Comet dynamics can be approximately described by a simple symplectic map, known as the Kepler map. More recent work suggests that Halley will evaporate, or split in two, within the next few tens of thousands of years, or will be ejected from the Solar System within a few hundred thousand years. Observations by D.W. Hughes suggest that Halley's nucleus has been reduced in mass by 80 to 90% over the last 2,000 to 3,000 revolutions.
Edmond Halley
Halley spent most of his time on lunar observations, but was also interested in the problems of gravity. One problem that attracted his attention was the proof of Kepler's laws of planetary motion. In August 1684, he went to Cambridge to discuss this with Isaac Newton, much as John Flamsteed had done four years earlier, only to find that Newton had solved the problem, at the instigation of Flamsteed with regard to the orbit of comet Kirch, without publishing the solution. Halley asked to see the calculations and was told by Newton that he could not find them, but promised to redo them and send them on later, which he eventually did, in a short treatise entitled, "On the motion of bodies in an orbit". Halley recognised the importance of the work and returned to Cambridge to arrange its publication with Newton, who instead went on to expand it into his "Philosophiæ Naturalis Principia Mathematica" published at Halley's expense in 1687. Halley's first calculations with comets were thereby for the orbit of comet Kirch, based on Flamsteed's observations in 1680-1. Although he was to accurately calculate the orbit of the comet of 1682, he was inaccurate in his calculations of the orbit of comet Kirch. They indicated a periodicity of 575 years, thus appearing in the years 531 and 1106, and presumably heralding the death of Julius Caesar in a like fashion in −44 (45 BCE). It is now known to have an orbital period of circa 10,000 years.
Johannes Remus Quietanus
In 1607, he observed the passage of a comet, and then wrote a booklet of some fifty pages titled "Gründliche Beschreibung des neuen monstrosischen Sternes, welcher anno Christi 1607 …am hohen Himmel geleichtet", ("Accurate description of the new monstrous star that shone in the sky from July 27 to mid-October in 1607"), where he proposed an astrological interpretation of this ""sign of God"". This was actually Halley's comet that did not yet bear the current name.
Christian Gärtner
Christian Gärtner (6 May 1705 – 31 December 1782) was a German telescope maker and astronomer, noted for his observation of the 1758 return of Halley's Comet.
Johann Franz Encke
Following a suggestion by Jean-Louis Pons, who suspected one of the three comets discovered in 1818 to be the same one already discovered by him in 1805, Encke began to calculate the orbital elements of this comet. At this time, all the known comets had an orbital period of seventy years and more, with an aphelion far beyond the orbit of Uranus. The most famous comet of this family was Comet Halley with its period of seventy-six years. So the orbit of the comet discovered by Pons was a sensation, because his orbit was found to have a period of 3.3 years, so that the aphelion had to be within the orbit of Jupiter. Encke predicted its return for 1822, but this return was observable only from the southern hemisphere and was seen by Carl Ludwig Christian Rümker in Australia. The comet was also identified with the one seen by Pierre Méchain in 1786 and by Caroline Herschel in 1795.