Editing Francis Baily (section)

==Astronomical work==
[[File:Baily, Francis – On the new method of determining the longitude by the culmination of the moon and stars, 1824 – BEIC 720900.jpg|thumb|left|upright|''On the new method of determining the longitude by the culmination of the moon and stars'', 1824]]

By 1820, Baily had already taken a leading part in the foundation of the [[Royal Astronomical Society]],<ref name=dreyer/> and he received its [[Gold Medal of the Royal Astronomical Society|Gold Medal]] in 1827<ref name=gold_medal>{{cite web | url=http://www.ras.org.uk/images/stories/awards/winners/gold_medallists.pdf | archive-url=https://web.archive.org/web/20150924084826/http://www.ras.org.uk/images/stories/awards/winners/gold_medallists.pdf | url-status=dead | archive-date=24 September 2015 | title=Gold Medal Winners | publisher=RAS | year=2014 | access-date=9 January 2015 }}</ref> for his preparation of the Society's ''Catalogue of 2881 stars'' (''Memoirs R. Astr. Soc.'' ii.).<ref name="EB1911"/> Later, in 1843, he would win the Gold Medal again.<ref name=gold_medal/> He was elected as [[President of the Royal Astronomical Society]] four times, with two-year terms each (1825–1827, 1833–1835, 1837–1839 and 1843–1845).<ref name=dreyer>{{cite book | last1 = Dreyer | first1 = John L. E. | last2 = Turner | first2 = Herbert H. | title = History of the Royal Astronomical Society, 1820–1920 | publisher = Royal Astronomical Society | volume = 1 | date = 1923 | location = London}}{{page needed|date=May 2021}}</ref>{{page needed|date=May 2021}}<ref name="Royal Astronomical Society">{{cite web|title=List of Presidents and Dates of Office|url=http://www.ras.org.uk/about-the-ras/a-brief-history/766-past-ras-presidents|work=A brief history of the RAS|publisher=Royal Astronomical Society|access-date=10 September 2012}}</ref> No other person has served in the position more than Baily's four times (a record he shares with [[George Airy]]), whilst his eight years in the post are a record.<ref name="Royal Astronomical Society"/>{{page needed|date=May 2021}}

The reform of the [[Nautical Almanac]] in 1829 was set on foot by his protests{{discuss}}. He was elected a Foreign Honorary Member of the [[American Academy of Arts and Sciences]] in 1832.<ref name=AAAS>{{cite web|title=Book of Members, 1780–2010: Chapter B|url=http://www.amacad.org/publications/BookofMembers/ChapterB.pdf|publisher=American Academy of Arts and Sciences|access-date=5 May 2011}}</ref> He recommended to the [[British Association]] in 1837, and in great part executed, the reduction of [[Joseph de Lalande]]'s and [[Nicolas de Lacaille]]'s catalogues containing about 57,000{{cn|date=June 2024|reason=This number is way too high}} stars; he superintended the compilation of the British Association's ''Catalogue of 8377 stars'' (''BAC'', published 1845);<ref>{{cite web | last = Ridpath  | first = Ian | url=http://www.ianridpath.com/startales/baily.html| title=Francis Baily and the British Association Catalogue}}</ref> and revised the catalogues of [[Tobias Mayer]], [[Ptolemy]], [[Ulugh Beg]], [[Tycho Brahe]], [[Edmund Halley]] and [[Hevelius]] (''Memoirs R. Astr. Soc.'' iv, xiii.).<ref name="EB1911"/>

His observations of "[[Baily's Beads]]", during an annular eclipse of the Sun on 15 May 1836, at Inch Bonney in [[Roxburghshire]], started the modern series of eclipse expeditions. The phenomenon, which depends upon the irregular shape of the Moon's limb, was so vividly described by him as to attract an unprecedented amount of attention to the total eclipse of 8 July 1842, observed by Baily himself at [[Pavia]].<ref name="EB1911"/>

[[File:August_21_2017_solar_eclipse_baily_beads_TLR2.jpg|thumb|[[Baily's beads]] four seconds before totality ([[Solar eclipse of August 21, 2017|August 21, 2017]])]]

In other work, he completed and discussed [[Henry Foster (scientist)|H. Foster]]'s pendulum experiments, deducing from them an ellipticity for the Earth of 1/289.48 (Memoirs R. Astr. Soc. vii.).  This value was corrected for the length of the seconds-pendulum by introducing a neglected element of reduction, and was used, in 1843, in the reconstruction of the standards of length. His laborious operations for determining the mean density of the Earth, carried out by [[Henry Cavendish]]'s method (1838–1842), yielded the authoritative value of 5.66.<ref name="EB1911"/>

Baily died in London on 30 August 1844 and was buried in the family vault in [[St Mary's Church, Thatcham|St Mary's Church]] in [[Thatcham]], [[Berkshire]]. His Account of the Rev. [[John Flamsteed]] (1835) is of fundamental importance to the scientific history of that time. It included a republication of the British Catalogue.<ref name="EB1911"/>

The [[lunar crater]] [[Baily (crater)|Baily]] was named in his honour, as was the rigid and thermally insensitive alloy used to cast the 1855 standard yard (''Baily's metal'', 16 parts copper, 2.5 parts tin, 1 part zinc), and a local primary school in the town of Thatcham (Francis Baily CofE Primary School).{{Citation needed|date=May 2019}}