Editing Anders Celsius (section)

==Career==
In 1730, Celsius published the {{lang|la|Nova Methodus distantiam solis a terra determinandi}} (''New Method for Determining the Distance from the Earth to the Sun''). His research also involved the study of auroral phenomena, which he conducted with his assistant [[Olof Hiorter]], and he was the first to suggest a connection between the [[aurora borealis]] and changes in the magnetic field of the Earth. He observed the variations of a compass needle and found that larger deflections correlated with stronger auroral activity. At [[Nuremberg]] in 1733, he published a collection of 316 observations of the aurora borealis made by himself and others over the period 1716–1732.<ref name="EB1911">{{cite EB1911|wstitle=Celsius, Anders|volume=5|page=609}}</ref>

Celsius traveled frequently in the early 1730s, including to Germany, Italy and France, when he visited most of the major European observatories. In Paris he advocated the measurement of an [[arc of the meridian]] in [[Laponia (historical province)|Lapland]]. In 1736, he participated in the expedition organized for that purpose by the [[French Academy of Sciences]], led by the French mathematician [[Pierre Louis Maupertuis]] (1698–1759) to measure a degree of [[latitude]].<ref name="EB1911"/> The aim of the expedition was to measure the length of a degree along a meridian, close to the pole, and compare the result with a similar expedition to [[Peru]], today in [[Ecuador]], near the [[equator]]. The expeditions confirmed [[Isaac Newton]]'s belief that the shape of the Earth is an [[ellipsoid]] flattened at the poles.{{sfn | Collinder | 1970 | p=}}{{pn|date=April 2022}}

[[Image:AndersCelsiusyoung.jpg|thumb|left|200px|Anders Celsius c. 1730s]]
In 1738, he published the {{lang|la|De observationibus pro figura telluris determinanda}} (''Observations on Determining the Shape of the Earth''). Celsius's participation in the Lapland expedition won him much respect in Sweden with the government and his peers, and played a key role in generating interest from the Swedish authorities in donating the resources required to construct a new modern observatory in Uppsala.<ref name="Bio" /> He was successful in the request, and Celsius founded the [[Uppsala Astronomical Observatory]] in 1741.<ref>{{Cite web |title=History of Astronomy in Uppsala |url=https://www.astro.uu.se/history/ |access-date=2022-04-23 |website=Uppsala Astronomical Observatory}}</ref> The observatory was equipped with instruments purchased during his long voyage abroad, comprising the most modern instrumental technology of the period.<ref name="MacTutor" />

He made observations of eclipses and various astronomical objects and published catalogues of carefully determined magnitudes for some 300 stars using his own photometric system (mean error=0.4 mag).{{sfn | Collinder | 1970 | p=}}{{pn|date=April 2022}}{{sfn|Celsius|1742|pp=171–180|loc= [https://archive.org/stream/kungligasvenskav1317kung#page/232/mode/2up Fig. 1.]}}<ref name="history">{{Cite web|url=http://www.astro.uu.se/history/celsius_scale.html|title=History of the Celsius temperature scale|website=www.astro.uu.se}}</ref> In 1742 he proposed the Celsius temperature scale in a paper to the [[Royal Society of Sciences in Uppsala]], the oldest Swedish scientific society, founded in 1710. His thermometer was calibrated with a value of 0 for the boiling point of water and 100 for the freezing point. In 1745, a year after Celsius's death, the scale was reversed by [[Carl Linnaeus]] to facilitate more practical measurement.<ref name="reversed">{{Cite web|url=https://www.botan.uu.se/learning/linnaeus-online/the-life-of-Linnaeus/linnaeus-the-doctor-of-medicine/linnaeus-grows-bananas-and-comes-up-with-a-modern-thermometer/linnaeus-thermometer/|title=Linnaeus' thermometer |publisher=Uppsala University}}</ref>

[[Image:UppsalaCelsiusObservatory Busser.jpg|thumb|200px|right|The observatory of Anders Celsius, from a contemporary engraving]]
Celsius conducted many geographical measurements for the Swedish General map, and was one of earliest to note that much of Scandinavia is slowly rising above sea level, a continuous process which has been occurring since the melting of the ice from the latest [[Quaternary glaciation|ice age]]. However, he wrongly posed the notion that the water was [[evaporating]].{{sfn | Collinder | 1970 | p=}}{{pn|date=April 2022}}

In 1725 he became secretary of the Royal Society of Sciences in Uppsala, and served at this post until his death from [[tuberculosis]] in 1744. He supported the formation of the [[Royal Swedish Academy of Sciences]] in [[Stockholm]] in 1739 by Linnaeus and five others, and was elected a member at the first meeting of this academy. It was in fact Celsius who proposed the new academy's name.<ref>{{Cite web|url=https://runeberg.org/nfcl/0071.html|title=109-110 (Nordisk familjebok / Uggleupplagan. 32. Werth - Väderkvarn)|date=29 August 1921|website=runeberg.org}}</ref>