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 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 ...

of French and

Huguenot The Huguenots ( , also , ) were a religious group of French Protestants who held to the Reformed, or Calvinist, tradition of Protestantism. The term, which may be derived from the name of a Swiss political leader, the Genevan burgomaster Be ...

descent who was born in Cushendun,

County Antrim County Antrim (named after the town of Antrim, ) is one of six counties of Northern Ireland and one of the thirty-two counties of Ireland. Adjoined to the north-east shore of Lough Neagh, the county covers an area of and has a population ...

, Ireland. He was educated in England at

Marlborough College ( 1 Corinthians 3:6: God gives the increase) , established = , type = Public SchoolIndependent day and boarding , religion = Church of England , president = Nicholas Holtam , head_label = Master , head = Louis ...

and

Trinity College, Cambridge Trinity College is a 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 college at either Cambridge or Oxford. ...

. After a spell teaching at

Lancing College Lancing College is a public school (English independent day and boarding school for pupils aged 13–18) in southern England, UK. The school is located in West Sussex, east of Worthing near the village of Lancing, on the south coast of England. ...

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 ...

in 1891. He joined the

Royal Astronomical Society (Whatever shines should be observed) , predecessor = , successor = , formation = , founder = , extinction = , merger = , merged = , type = NG ...

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 collaborati ...

and was president from 1904-1906 and directed its

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...

section 1898-1901 and 1907-1938. In 1910 for their studies of Halley’s Comet Crommelin and

Philip Herbert Cowell Philip Herbert Cowell FRS (1870 – 1949) was a British astronomer. Philip Herbert Cowell was born in Calcutta, India on the 7 August 1870, and educated at Eton and Trinity College, Cambridge. He became second chief assistant at the Royal Gre ...

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 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 purpose ...

. 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. In 1882, the ''Astronomische Gesellschaft'' founded the Centra ...

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 Gen ...

was one of Andrews 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 owned by Integrated Whale Media Investments and the Forbes family. Published eight times a year, it features articles on finance, industry, investing, and marketing topics. ''Forbes'' also r ...

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 bipeds 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 Va ...

- 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 ha ...

, 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 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 the Earth, totally or partially. Such an alignment occurs during an eclipse season, approximately every six mon ...

expeditions including those of

1896 Events January–March * 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 that ...

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), 2 ...

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 ...

. In

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

he went to Sobral, in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, 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 Einstein's theory of gravity, is the differential geometry, geometric scientific theory, theory of gravitation published by Albert Einstein in 1915 and is the current descr ...

, which

Albert Einstein Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theor ...

had proposed in 1916.

Named after Crommelin

Comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...

Crommelin (lunar crater) Crommelin is an ancient lunar impact crater that is located in the vicinity of the south pole of the Moon, on the far side ''The Far Side'' is a single-panel comic created by Gary Larson and syndicated by Chronicle Features and then Univers ...

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), and the name was appr ...

Asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

1899 Crommelin

References

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 County Antrim {{UK-astronomer-stub