The Great Comet of 1819, officially designated as C/1819 N1, also known as Comet Tralles, was an exceptionally bright and easily visible

comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

, approaching an

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

of 1–2, discovered July 1, 1819 by the German astronomer

Johann Georg Tralles Johann Georg Tralles (15 October 1763 – 19 November 1822) was a German mathematician and physicist. He was born in Hamburg, Germany and was educated at the University of Göttingen beginning in 1783. He became a professor at the University ...

Berlin Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...

. It was the first comet analyzed using

polarimetry Polarimetry is the measurement and interpretation of the polarization of transverse waves, most notably electromagnetic waves, such as radio or light waves. Typically polarimetry is done on electromagnetic waves that have traveled through or ha ...

, by French mathematician

François Arago Dominique François Jean Arago (), known simply as François Arago (; Catalan: , ; 26 February 17862 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of the Carbonari revolutionaries and politician. Early l ...

Discovery

On July 1, 1819,

in Berlin observed a brilliant comet low in the sky during the evening

twilight Twilight is daylight illumination produced by diffuse sky radiation when the Sun is below the horizon as sunlight from the upper atmosphere is scattered in a way that illuminates both the Earth's lower atmosphere and also the Earth's surf ...

. It was confirmed the next night by the

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

Johann Elert Bode Johann Elert Bode (; 19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularisation of the Titius–Bode law. Bode determined the orbit of Uranus and suggested the planet's name. Life and career B ...

, also in Berlin.

Observations

On July 2, Tralles found the comet to have a

coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to Nociception, respond normally to Pain, painful stimuli, light, or sound, lacks a normal Circadian rhythm, sleep-wake cycle and does not initiate ...

of 40″. On July 3,

Friedrich Georg Wilhelm von Struve Friedrich Georg Wilhelm von Struve (, trans. ''Vasily Yakovlevich Struve''; 15 April 1793 – ) was a Baltic German astronomer and geodesist. He is best known for studying double stars and initiating a triangulation survey later named Struve ...

measured the

nucleus Nucleus (: nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucleu ...

at 8″ with a

tail The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to los ...

of several degrees.

Heinrich Wilhelm Matthias Olbers Heinrich Wilhelm Matthias Olbers (; ; 11 October 1758 – 2 March 1840) was a German astronomer. He found a convenient method of calculating the orbit of comets, and in 1802 and 1807, discovered the second and the fourth asteroids Pallas and ...

reported that the nucleus had an apparent magnitude of 1–2 and a tail about 7–8° long. The comet was last sighted by Struve on October 25. Also on July 3,

used a

polarimeter A polarimeter is a scientific instrument used to measure optical rotation: the angle of rotation caused by passing linearly polarized light through an Optical activity, optically active substance. Some chemical substances are optically active, ...

of his own invention to analyze the light from the comet's tail and discovered that it was polarized. He then observed the nearest star,

Capella Capella is the brightest star in the northern constellation of Auriga. It has the Bayer designation α Aurigae, which is Latinisation of names, Latinised to Alpha Aurigae and abbreviated Alpha Aur or α Aur. Capella is the lis ...

, which did not show polarized light. This indicated that some light from the comet's tail was reflected from the sun. This marked the first

polarimetric Polarimetry is the measurement and interpretation of the polarization of transverse waves, most notably electromagnetic waves, such as radio or light waves. Typically polarimetry is done on electromagnetic waves that have traveled through or hav ...

observation of a comet.

Transit of the Sun

After the

orbital elements Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same o ...

of the comet were calculated by Olbers, he discovered that a transit of the Sun by the comet had occurred on June 26, days before its first observations. He reported this to Bode on July 27. After this announcement many Sun observers searched their notes to see if they had noted something unusual that day. noted that he saw on that day a round nebulousity with a bright spot near its center and made a sketch of it. Canon Stark from

Augsburg Augsburg ( , ; ; ) is a city in the Bavaria, Bavarian part of Swabia, Germany, around west of the Bavarian capital Munich. It is a College town, university town and the regional seat of the Swabia (administrative region), Swabia with a well ...

also noted in ''Meteorologisches Jahrbuch'' that he saw an ill-defined small spot in the Sun at 7:15 A.M. on June 26, 15' 25" from the west limb of the Sun, that wasn't present at noon.

John Russell Hind John Russell Hind FRS FRSE LLD (12 May 1823 – 23 December 1895) was an English astronomer. Life and work John Russell Hind was born in 1823 in Nottingham, the son of lace manufacturer John Hind and Elizabeth Russell, and was educated at ...

noted that the positions given by Johann Wilhelm Pastorff were considerably different than the expected location of the comet, and also considered it improbable that the comet would resemble Pastorff's sketch. On the other hand, he concluded that Canon Stark perhaps did observe the comet, although the mentioned position was a bit off. In a 2017 paper, astronomer Richard L. Branham Jr. agreed that Canon Stark likely did see the transit.

Orbit

Orbital elements Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same o ...

for the comet were calculated by several astronomers. The orbit is classified as parabolic and is nearly perpendicular to Earth's orbital plane, with an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 80°. It passed closest to the Earth on June 25 at a distance of and closest to the Sun on June 28 at . The orbit of the comet and its transit of the Sun were later analyzed by astronomer

. In 2016 the orbit was recalculated based on a total of 692 observations of the comet taken in 1819, with the resulting conclusion that the comet will not return for over 3,000 years and represents no threat to the Earth, and that Near Eastern records around 2550 BCE may be found to mention its earlier passage.

In literature

The comet was widely seen and noted by people who were not astronomers. Poet

John Keats John Keats (31 October 1795 – 23 February 1821) was an English poet of the second generation of Romantic poets, along with Lord Byron and Percy Bysshe Shelley. His poems had been in publication for less than four years when he died of tub ...

noted how he and his wife Fanny had stared at the comet. Historian

Nathaniel Philbrick Nathaniel Philbrick (born June 11, 1956) is an American author of history, winner of the National Book Award, and a finalist for the Pulitzer Prize. His maritime history, ''In the Heart of the Sea: The Tragedy of the Whaleship Essex'', based on w ...

writes about the great comet seen in July 1819 by the people on the island of

Nantucket Nantucket () is an island in the state of Massachusetts in the United States, about south of the Cape Cod peninsula. Together with the small islands of Tuckernuck Island, Tuckernuck and Muskeget Island, Muskeget, it constitutes the Town and Co ...

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

in his 2000 book, '' In the Heart of the Sea''. The comet was observed by the Stephen Long expedition to the

Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...

from near present day

Jefferson City, Missouri Jefferson City, informally Jeff City, is the List of capitals in the United States, capital of the U.S. state of Missouri. It had a population of 43,228 at the 2020 United States census, ranking as the List of cities in Missouri, 16th most popu ...

References

External links

JPL DASTCOM Orbital Elements
* {{DEFAULTSORT:1819

1819 Events January–March * January 2 – The Panic of 1819, the first major peacetime financial crisis in the United States, begins. * January 25 – Thomas Jefferson founds the University of Virginia. * January 29 – Si ...

Astronomical objects discovered in 1819 Great comets