Jean-Louis Pons

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Jean-Louis Pons
Pons 1.jpg
Jean-Louis Pons
Born(1761-12-24)24 December 1761
Died14 October 1831(1831-10-14) (aged 69)
Awards Lalande Prize (1818, 1820, 1827)
Scientific career
Fields Astronomy

Jean-Louis Pons (24 December 1761 – 14 October 1831) was a French astronomer. [1] Despite humble beginnings and being self-taught, he went on to become the greatest visual comet discoverer of all time: between 1801 and 1827 Pons discovered thirty-seven comets, more than any other person in history.

France Republic with mainland in Europe and numerous oversea territories

France, officially the French Republic, is a country whose territory consists of metropolitan France in Western Europe and several overseas regions and territories. The metropolitan area of France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean. It is bordered by Belgium, Luxembourg and Germany to the northeast, Switzerland and Italy to the east, and Andorra and Spain to the south. The overseas territories include French Guiana in South America and several islands in the Atlantic, Pacific and Indian oceans. The country's 18 integral regions span a combined area of 643,801 square kilometres (248,573 sq mi) and a total population of 67.3 million. France, a sovereign state, is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre. Other major urban areas include Lyon, Marseille, Toulouse, Bordeaux, Lille and Nice.

Astronomer scientist who studies celestial bodies

An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets, and galaxies – in either observational or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, solar astronomy, the origin or evolution of stars, or the formation of galaxies. Related but distinct subjects like physical cosmology, which studies the Universe as a whole.

Comet Icy small Solar System body

A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of solar radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times the Earth's diameter, while the tail may stretch one astronomical unit. If sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° across the sky. Comets have been observed and recorded since ancient times by many cultures.


Early life

Pons was born at Peyre, Hautes-Alpes, to a poor family; he received little formal education. In 1789, he began working for the Marseille observatory as a caretaker, and gradually gained some experience in assisting the astronomers with observations. He learned to make observations himself, showing a remarkable ability to remember star fields and note changes in them.

La Piarre Commune in Provence-Alpes-Côte dAzur, France

La Piarre is a commune in the Hautes-Alpes department in southeastern France.

Hautes-Alpes Department of France

Hautes-Alpes is a department of Provence-Alpes-Côte d'Azur in southeastern France named after the Alps mountain range.

Marseille Second-largest city of France and prefecture of Provence-Alpes-Côte dAzur

Marseille is the second-largest city of France. The main city of the historical province of Provence, it nowadays is the prefecture of the department of Bouches-du-Rhône and region of Provence-Alpes-Côte d'Azur. It is located on France's south coast near the mouth of the Rhône. The city covers an area of 241 km2 (93 sq mi) and had a population of 852,516 in 2012. Its metropolitan area, which extends over 3,173 km2 (1,225 sq mi) is the third-largest in France after Paris and Lyon, with a population of 1,831,500 as of 2010.

In his early astronomical career, the unassuming and trusting Pons was often the target of jokes perpetrated by more experienced astronomers. Franz Xaver von Zach once advised him to look for comets when sunspots were visible, though in doing so Zach may have inadvertently given Pons very good advice. [2]

Franz Xaver von Zach astronomer

Baron Franz Xaver von Zach was a Hungarian astronomer born at Pest, Hungary.

Sunspot temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding region

Sunspots are temporary phenomena on the Sun's photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Sunspots usually appear in pairs of opposite magnetic polarity. Their number varies according to the approximately 11-year solar cycle.

Career as an astronomer

Pons made his first comet discovery, jointly attributed to Charles Messier, on 11 July 1801. He appears to have used telescopes and lenses of his own design; his "Grand Chercheur" ("Great Seeker") seems to have been an instrument with large aperture and short focal length, similar to a "comet seeker". [3] However, he was not an especially diligent recorder of his observations, and his notes were often extremely vague. [3]

Charles Messier 18th and 19th-century French astronomer

Charles Messier was a French astronomer most notable for publishing an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the Messier objects. The purpose of the catalogue was to help astronomical observers, in particular comet hunters like himself, distinguish between permanent and transient visually diffuse objects in the sky.

Comet seeker

A comet seeker is a type of small telescope adapted especially to searching for comets: commonly of short focal length and large aperture, in order to secure the greatest brilliancy of light.

In 1819, Pons became the director of the new observatory at Marlia near Lucca, which he left in 1825 to teach astronomy at La Specola, in Florence. Around that time he accepted the opportunity to become Director of the Florence Observatory at the request of the Grand Duke of Tuscany. [4]

Lucca Comune in Tuscany, Italy

Lucca is a city and comune in Tuscany, Central Italy, on the Serchio, in a fertile plain near the Tyrrhenian Sea. It is the capital of the Province of Lucca. It is famous for its intact Renaissance-era city walls.

La Specola

The Museum of Zoology and Natural History, best known as La Specola, is an eclectic natural history museum in Florence, central Italy, located next to the Pitti Palace. The name Specola means observatory, a reference to the astronomical observatory founded there in 1790. It now forms part of the Museo di Storia Naturale di Firenze. This museum is part of what are now six different collections at four different sites for the Museo di Storia Naturale di Firenze.

Florence Comune in Tuscany, Italy

Florence is the capital city of the Italian region of Tuscany. It is the most populous city in Tuscany, with 383,084 inhabitants in 2013, and over 1,520,000 in its metropolitan area.

He discovered five periodic comets, three of which, 7P/Pons–Winnecke, 12P/Pons–Brooks and 273P/Pons–Gambart, bear his name. One observed on 26 November 1818 was named Comet Encke (now 2P/Enke) after Johann Franz Encke, who calculated its orbit and its remarkably short period (Encke, however, continued to refer to the comet as "Pons's Comet"). Pons also co-discovered the comet formerly known as "Pons–Coggia–Winnecke–Forbes" and today known as 27P/Crommelin after Andrew Crommelin, who calculated its orbit.

7P/Pons–Winnecke comet

7P/Pons–Winnecke is a periodic Jupiter-family comet in the Solar System. It made a very close approach to Earth in June 1927. The outward migration of perihelion created impressive meteor showers in 1916, 1921, and 1927.

12P/Pons–Brooks is a periodic comet with an orbital period of 71 years. It fits the classical definition of a Halley-type comet with. Its next closest approach to Earth is in 2024.

273P/Pons–Gambart, also called Comet Pons-Gambart, is a long-period comet first discovered on June 21, 1827 by Jean-Louis Pons and Jean-Félix Adolphe Gambart. It was lost and was not recovered until November 7, 2012, when amateur astronomer Rob Matson discovered a comet, and it was identified that the orbital calculations for Pons-Gambart were completely wrong.

Pons received the French Academy of Sciences's Lalande Prize in 1818 for his discovery of three comets in that year. He won it again in 1820 (jointly with Joseph Nicollet) for further comet discoveries at Marlia and for an unmatched third time in 1827 (jointly with Jean-Félix Adolphe Gambart) for discovering another seven comets at the Florence observatory. [4]

By 1827, Pons's eyesight had begun to fail, and he retired from observing altogether shortly before his death, on 14 October 1831. In his honour, a moon crater was named after him. [5]

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  1. McGown, Robert D. (2007). "Pons, Jean-Louis". In Hockey, Thomas; et al. Biographical dictionary of astronomers. vol. II, M-Z. Springer. p. 924.
  2. Calder, N. Comets: Speculation and Discovery, Courier, 1994, p.80
  3. 1 2 Roemer, E. Jean Louis Pons: Discoverer of Comets, San Francisco: Astronomical Society of the Pacific, 1960, p.2
  4. 1 2 Biographical Encyclopedia of Astronomers. p. 923.
  5. "The death certificate, as well as other personal pieces of information and scientific notes are preserved in the archive of the library of the Museo Galileo in Florence" (PDF).