Andrew Claude de la Cherois Crommelin (6 February 1865 – 20 September 1939) was an

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 ...

of French and

Huguenot The Huguenots ( , ; ) are a Religious denomination, religious group of French people, French Protestants who held to the Reformed (Calvinist) tradition of Protestantism. The term, which may be derived from the name of a Swiss political leader, ...

descent who was born in

Cushendun Cushendun () is a small coastal village in County Antrim, Northern Ireland. It sits off the A2 coast road between Cushendall and Ballycastle. It has a sheltered harbour and lies at the mouth of the River Dun and Glendun, one of the nine Glen ...

County Antrim County Antrim (named after the town of Antrim, County Antrim, Antrim, ) is one of the six counties of Northern Ireland, located within the historic Provinces of Ireland, province of Ulster. Adjoined to the north-east shore of Lough Neagh, the c ...

, Ireland. He was educated in England at

Marlborough College Marlborough College is a Public school (United Kingdom), public school (English private boarding school) for pupils aged 13 to 18 in Marlborough, Wiltshire, England. It was founded as Marlborough School in 1843 by the Dean of Manchester, George ...

and

Trinity College, Cambridge Trinity College is a Colleges of the University of Cambridge, constituent college of the University of Cambridge. Founded in 1546 by King Henry VIII, Trinity is one of the largest Cambridge colleges, with the largest financial endowment of any ...

. After a spell teaching at

Lancing College Lancing College is a Public school (United Kingdom), public school (English Private schools in the United Kingdom, private boarding school, boarding and day school) for pupils aged 13–18 in southern England, UK. The school is located in West S ...

he found permanent employment at the

Royal Greenwich Observatory The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, temporarily moved south from Greenwich to Herstmonceux) is an observatory situated on a hill in G ...

in 1891. He joined the

Royal Astronomical Society The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...

in 1888 and was its president from 1929-1931. In 1895 he joined the

British Astronomical Association The British Astronomical Association (BAA) was formed in 1890 as a national body to support the UK's amateur astronomers. Throughout its history, the BAA has encouraged observers to make scientifically valuable observations, often in collaborat ...

and was president from 1904-1906 and directed its

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 ...

section 1898-1901 and 1907-1938. In 1910 for their studies of Halley’s Comet Crommelin and Philip Herbert Cowell jointly received the

Prix Jules Janssen The Prix Jules Janssen is the highest award of the Société astronomique de France (SAF), the French astronomical society. This annual prize is given to a professional French astronomer or to an astronomer of another nationality in recognition ...

from the

Société astronomique de France The Société astronomique de France (SAF; ), the France, French astronomical society, is a non-profit association in the public interest organized under French law (Association loi de 1901). Founded by astronomer Camille Flammarion in 1887, its ...

. For this work they also received the Lindemann prize of the

Astronomische Gesellschaft __NOTOC__ The ''Astronomische Gesellschaft'' is an astronomical society established in 1863 in Heidelberg, the second oldest astronomical society after the Royal Astronomical Society. History In 1882, the ''Astronomische Gesellschaft'' founded t ...

in Germany. In 1914 Crommelin published an introductory book on astronomy “The Star World”. Crommelin had four children, of whom two died in a climbing accident on Pillar Rock, Ennerdale, in 1933. The de la Cherois line was succeeded through Crommelin's daughter Andrina. The author

May Crommelin Maria Henrietta de la Cherois Crommelin, known as May de la Cherois Crommelin, (1850–1930) was a novelist and travel writer born in Ulster, Ireland at Carrowdore Castle in County Down.Burke's Genealogical and Heraldic History of the Landed Ge ...

was one of Andrew’s cousins. ACDCrommelin-early

An expert on comets, his calculation of orbits of previously identified Comet Pons 1818 II, Comet Coggia-Winnecke 1873 VII, and Comet

Forbes ''Forbes'' () is an American business magazine founded by B. C. Forbes in 1917. It has been owned by the Hong Kong–based investment group Integrated Whale Media Investments since 2014. Its chairman and editor-in-chief is Steve Forbes. The co ...

1928 III in 1929, showed that these were one and the same periodic comet. It thus received the rather unwieldy name "Comet

Pons The pons (from Latin , "bridge") is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of ...

- Coggia- Winnecke-

". In 1948, he was posthumously honored when the comet was renamed after him alone (today, in modern nomenclature, it is designated

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 <

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 ...

, where the periodic comet is named after the person who determined the orbit rather than the possibly-multiple discoverers and re-discoverers at each apparition. In 1937 Crommelin and

Mary Proctor Mary Proctor (1 April 1862 – 11 September 1957) was a British-American popularizer of astronomy. While not a professional astronomer, Proctor became well known for her books and articles written for the public – particularly her chil ...

jointly published a book entitled "Comets: Their Nature, Origin, and Place in the Science of Astronomy”. Crommelin took part in several

solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during the eclipse season i ...

expeditions including those of

1896 Events January * January 2 – The Jameson Raid comes to an end as Jameson surrenders to the Boers. * January 4 – Utah is admitted as the 45th U.S. state. * January 5 – An Austrian newspaper reports Wilhelm Röntgen's dis ...

1900 As of March 1 ( O.S. February 17), when the Julian calendar acknowledged a leap day and the Gregorian calendar did not, the Julian calendar fell one day further behind, bringing the difference to 13 days until February 28 ( O.S. February 15 ...

and

1905 As the second year of the massive Russo-Japanese War begins, more than 100,000 die in the largest world battles of that era, and the war chaos leads to the 1905 Russian Revolution against Nicholas II of Russia (Shostakovich's 11th Symphony i ...

. In

1919 Events January * January 1 ** The Czechoslovak Legions occupy much of the self-proclaimed "free city" of Pressburg (later Bratislava), enforcing its incorporation into the new republic of Czechoslovakia. ** HMY ''Iolaire'' sinks off th ...

he went to Sobral, in

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, and measured the amount of deflection of light caused by the gravitational field of the Sun. The results from these observations were crucial in providing confirmation of the

General Theory of Relativity General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physi ...

, which

Albert Einstein Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence f ...

had proposed in 1916.

Named after Crommelin

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 ...

Crommelin (lunar crater) Crommelin is an ancient lunar impact crater that is located in the vicinity of the south pole of the Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of ( ...

Crommelin (Martian crater) Crommelin is an impact crater in the Oxia Palus quadrangle of Mars, located at 5.1°N latitude and 10.2°W longitude. It is 113.9 km in diameter. It was named after British astronomer Andrew Crommelin (1865–1939); the name was approved ...

Asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

1899 Crommelin

References

{{DEFAULTSORT:Cherois Crommelin, Andrew Claude De La 1865 births 1939 deaths 19th-century British astronomers 20th-century British astronomers Alumni of Trinity College, Cambridge People educated at Marlborough College Presidents of the Royal Astronomical Society Recipients of the Lalande Prize People from Cushendun Scientists from County Antrim