View source for Andrew Claude de la Cherois Crommelin

{{Short description|19/20th-century Irish astronomer}}
{{Use dmy dates|date=September 2019}}

'''Andrew Claude de la Cherois Crommelin''' (6 February 1865 &ndash; 20 September 1939) was an [[astronomer]] of French and [[Huguenot]] descent who was born in [[Cushendun]], [[County Antrim]], Ireland.<ref name="obit_mnras">{{cite journal
   | last = Davidson 
   | first = C. R.
   | author-link = 
   | title = Andrew Claude de la Cherois Crommelin
   | journal = [[Monthly Notices of the Royal Astronomical Society]]
   | volume = 100 
   | number = 4 
   | pages = 234–36
   | date = 1940
   | bibcode = 1940MNRAS.100..234D
   | url = http://articles.adsabs.harvard.edu/full/1940MNRAS.100..234.
   | accessdate = 7 November 2015
   | doi=10.1093/mnras/100.4.234
| doi-access = free
   }}</ref><ref name="obit_obs">{{cite journal
   | last =
   | first =
   | author-link =
   | title = Obituary: Dr. A. C. D. Crommelin
   | journal = [[The Observatory (journal)|The Observatory]]
   | volume = 63
   | number = 788
   | pages = 11–13
   | date = 1940
   | bibcode = 1940Obs....63...11.
   | url = http://articles.adsabs.harvard.edu/full/1940Obs....63...11.
   | accessdate = 7 November 2015
}}</ref><ref name="obit_jbaa">{{cite journal
   | last = Phillips 
   | first = T. E. R.
   | author-link = T. E. R. Phillips
   | title = Andrew Claude de la Cherois Crommelin
   | journal = [[Journal of the British Astronomical Association]]
   | volume = 50
   | number = 2 
   | pages = 75–78
   | date = 1940
   | bibcode = 1939JBAA...50...75.
   | url = http://articles.adsabs.harvard.edu/full/1939JBAA...50...75.
   | accessdate = 7 November 2015
}}</ref><ref name="biogencastron">{{cite book
   | last = Williams
   | first = Thomas R.
   | author-link =
   | contribution = Crommelin, Andrew Claude de la Cherois
   | year = 2014
   | title = Biographical Encyclopedia of Astronomers
   | pages = 483–484
   | editor-last = Hockey    | editor-first = Thomas
   | editor2-last = Trimble  | editor2-first = Virginia
   | editor3-last = Williams | editor3-first = Thomas R.
   | publisher = [[Springer Publishing]]
   | place = New York
   | isbn = 978-1-4419-9917-7
   | doi = 10.1007/978-1-4419-9917-7_9042
| title-link = Biographical Encyclopedia of Astronomers
   }}</ref><ref name="odnb">{{cite encyclopedia
   | last = Meadows
   | first = A. Jack
   | author-link =
   | contribution = Crommelin, Andrew Claude de la Cherois
   | year = 2004
   | encyclopedia = [[Oxford Dictionary of National Biography]]
   | publisher = [[Oxford University Press]]
   | place = Oxford, England
   | doi = 10.1093/ref:odnb/57187 
   | url = http://www.oxforddnb.com/view/article/57187
| title = Crommelin, Andrew Claude de la Cherois (1865–1939), astronomer &#124; Oxford Dictionary of National Biography
   | url-access = subscription
   }}</ref>
He was educated in England at [[Marlborough College]] and [[Trinity College, Cambridge]]. After a spell teaching at [[Lancing College]] he found permanent employment at the [[Royal Observatory, Greenwich|Royal Greenwich Observatory]] in 1891.<ref>{{acad|id=CRMN883AC|name=Crommelin, Andrew Claude <nowiki>[D'Elacherois or De La Cherois]</nowiki>}}</ref><ref>{{Cite web|title=A.C.D. Crommelin|url=http://www.crommelin.org/history/Biographies/1865AndrewdelaCherois-Crommelin/index.htm|access-date=2021-05-21|website=www.crommelin.org}}</ref> He joined the [[Royal Astronomical Society]] in 1888 and was its president from 1929-1931. In 1895 he joined the [[British Astronomical Association]] and was president from 1904-1906 and directed its [[comet]] section 1898-1901 and 1907-1938.<ref>{{Cite web|title=1939JBAA...50...75. Page 75|url=http://articles.adsabs.harvard.edu/cgi-bin/nph-journal_query?volume=50&plate_select=NO&page=75&plate=&cover=&journal=JBAA.|access-date=2021-05-19|website=articles.adsabs.harvard.edu}}</ref>

In 1910 for their studies of [[Halley's Comet|Halley’s]] Comet Crommelin and [[Philip Herbert Cowell]] jointly received the [[Prix Jules Janssen]] from the [[Société astronomique de France]].<ref>{{Cite web|title=EN-Janssen Prize – Société astronomique de France|url=https://saf-astronomie.fr/en-janssen-prize/|access-date=2021-05-21|website=saf-astronomie.fr}}</ref><ref>{{Cite web|title=1910JBAA...20..387. Page 391|url=http://articles.adsabs.harvard.edu/cgi-bin/nph-journal_query?volume=20&plate_select=NO&page=391&plate=&cover=&journal=JBAA.|access-date=2021-05-22|website=articles.adsabs.harvard.edu}}</ref> For this work they also received the Lindemann prize of the [[Astronomische Gesellschaft]] in Germany.<ref>{{Cite web|title=Andrew Claude de la Cherois Crommelin {{!}} Science Museum Group Collection|url=https://collection.sciencemuseumgroup.org.uk/people/cp134026/andrew-claude-de-la-cherois-crommelin|access-date=2021-05-21|website=collection.sciencemuseumgroup.org.uk|language=en}}</ref><ref>{{Cite book|last1=Cowell|first1=Philip Herbert|url=http://archive.org/details/essayonreturnofh00cowerich|title=Essay on the return of Halleys comet|last2=Crommelin|first2=Andrew Claude De la Cherois|date=1910|publisher=Leipzig, In kommission bei W. Engelmann|others=University of California Libraries|bibcode=1910erhc.book.....C}}</ref>

In 1914 Crommelin published an introductory book on astronomy “The Star World”.<ref>{{Cite book|last=CROMMELIN|first=Andrew Claude de la Cherois|url=https://books.google.com/books?id=3XLpPQAACAAJ&q=star+world,+crommelin|title=The Star World|date=1914|publisher=Collins|language=en}}</ref>

Crommelin had four children, of whom two died in a climbing accident on [[Pillar Rock, Ennerdale]], in 1933.<ref>{{Cite web|title=1933JBAA...43..387. Page 390|url=http://articles.adsabs.harvard.edu/cgi-bin/nph-journal_query?volume=43&plate_select=NO&page=390&plate=&cover=&journal=JBAA.|access-date=2021-05-20|website=articles.adsabs.harvard.edu}}</ref> The de la Cherois line was succeeded through Crommelin's daughter Andrina. The author [[May Crommelin]] was one of Andrew’s cousins.

[[File:ACDCrommelin-early.jpg|thumb|Andrew Claude de la Cherois Crommelin.]]

An expert on comets, his calculation of orbits of previously identified Comet Pons 1818 II, Comet Coggia-Winnecke 1873 VII, and Comet [[37P/Forbes|Forbes]] 1928 III in 1929, showed that these were one and the same periodic comet.<ref>{{Cite journal|title=1936AN....261...83C Page 83/84|url=http://articles.adsabs.harvard.edu/full/1936AN....261...83C|access-date=2021-05-21|journal=Astronomische Nachrichten|bibcode=1936AN....261...83C |last1=Crommelin |first1=A. C. D. |date=1936 |volume=261 |issue=5 |page=83 |doi=10.1002/asna.19362610504 }}</ref><ref>{{Cite journal|title=1929MNRAS..89..556C Page 556|url=http://articles.adsabs.harvard.edu/full/1929MNRAS..89..556C|access-date=2021-05-21|journal=Monthly Notices of the Royal Astronomical Society|bibcode=1929MNRAS..89..556C |last1=Crommelin |first1=A. C. D. |date=1929 |volume=89 |page=556 |doi=10.1093/mnras/89.6.556 |doi-access=free }}</ref> It thus received the rather unwieldy name "Comet [[Jean-Louis Pons|Pons]]-[[Jérôme Eugène Coggia|Coggia]]-[[Friedrich August Theodor Winnecke|Winnecke]]-[[Alexander F. I. Forbes|Forbes]]".  In 1948, he was posthumously honored when the comet was renamed after him alone (today, in modern nomenclature, it is designated [[27P/Crommelin]]). This is similar to the case of [[Comet Encke]], 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”.<ref>{{Cite book|last1=Proctor|first1=Mary|url=http://archive.org/details/comets032795mbp|title=Comets|last2=Crommelin|first2=A. C. D.|date=1937|publisher=The Technical Press Limited Company.|others=Osmania University, Digital Library Of India}}</ref>

Crommelin took part in several [[solar eclipse]] expeditions including those of [[Solar eclipse of August 9, 1896|1896]], [[Solar eclipse of May 28, 1900|1900]] and [[Solar eclipse of August 30, 1905|1905]].<ref>{{Cite journal|title=1898MmBAA...6R..23C Page 23|url=http://articles.adsabs.harvard.edu/full/1898MmBAA...6R..23C|access-date=2021-05-21|journal=Memoirs of the British Astronomical Association|bibcode=1898MmBAA...6R..23C |last1=Crommelin |first1=Andrew C. D. |date=1898 |volume=6 |page=23 }}</ref><ref>{{Cite book|last1=British Astronomical Association|url=http://archive.org/details/eclipstotalsolar00britrich|title=The total solar eclipse, 1900; report of the expeditions organized by the British astronomical association to observe the total solar eclipse of 1900, May 28|last2=Maunder|first2=E. Walter (Edward Walter)|date=1901|publisher=London, "Knowledge" office|others=University of California Libraries}}</ref><ref>{{Cite book|last=British Astronomical Association|url=http://archive.org/details/totalsolareclip00assogoog|title=The Total Solar Eclipse, 1905: Reports of Observations Made by Members of the British ...|date=1906|publisher=Eyre and Spottiswoode|others=New York Public Library|language=English}}</ref> In [[Solar eclipse of May 29, 1919|1919]] he went to [[Sobral, Ceará|Sobral]], in [[Brazil]], and measured the amount of deflection of light caused by the [[Tests of general relativity|gravitational field of the Sun]].<ref>{{Cite journal|title=1919Obs....42..368C Page 368|url=http://articles.adsabs.harvard.edu//full/1919Obs....42..368C/0000368.000.html|access-date=2021-05-21|journal=The Observatory|bibcode=1919Obs....42..368C |last1=Crommelin |first1=A. C. D. |date=1919 |volume=42 |page=368 }}</ref> The results from these observations were crucial in providing confirmation of the [[General relativity|General Theory of Relativity]], which [[Albert Einstein]] had proposed in 1916.

==Named after Crommelin==
* [[Comet]] [[27P/Crommelin]]
* [[Crommelin (lunar crater)]]
* [[Crommelin (Martian crater)]]
* [[Asteroid]] [[1899 Crommelin]]<ref>{{cite book|title=(1899) Crommelin In: Dictionary of Minor Planet Names |pages = 152|publisher=Springer |date=2003 |isbn=978-3-540-29925-7 |doi=10.1007/978-3-540-29925-7_1900 |chapter = (1899) Crommelin}}</ref>

==References==
{{Reflist}}

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