Anders Planman (1724 – 25 April 1803) was a Finnish astronomer, professor of physics and mathematician. He was one of the first people to make systematical astronomical observations in Finland.

Life

Planman came from a Swedish-speaking Finnish family and his father was a lieutenant. He studied at the

Royal Academy of Turku The Royal Academy of Turku or the Royal Academy of Åbo ( sv, Kungliga Akademin i Åbo or ; la, Regia Academia Aboensis; fi, Turun akatemia) was the first university in Finland, and the only Finnish university that was founded when the country ...

from 1744 to 1754 and then continued his studies at

Uppsala University Uppsala University ( sv, Uppsala universitet) is a public research university in Uppsala, Sweden. Founded in 1477, it is the oldest university in Sweden and the Nordic countries still in operation. The university rose to significance during ...

. In 1756 he received the grade of

docent The title of docent is conferred by some European universities to denote a specific academic appointment within a set structure of academic ranks at or below the full professor rank, similar to a British readership, a French " ''maître de con ...

in astronomy. In 1763 he was appointed professor of physics in Turku and retained the position until 1801, when he quit due to poor health. For three years he was also head of the academy. Because the tenureship as a professor was sometimes without a salary, Planman had also been ordained and worked as parish priest in

Nousiainen Nousiainen (; sv, Nousis) is a municipality of Finland. It is located in the Southwest Finland region, from Turku along Highway 8 ( E8). The Finnish-speaking municipality has a population of () and covers an area of of which is water. The p ...

and

Paimio Paimio (; sv, Pemar) is a town and municipality of Finland. It is located in the province of Western Finland and is part of the Southwest Finland region. The municipality has a population of () and covers an area of of which is water. The pop ...

. From 1767 he was a member of the Royal Swedish Academy of Sciences. He was also a member of the

Royal Society of Sciences in Uppsala The Royal Society of Sciences in Uppsala ( sv, Kungliga Vetenskaps-Societeten i Uppsala), is the oldest of the royal academies in Sweden, having been founded in 1710. The society has, by royal decree of 1906, 50 Swedish fellows and 100 foreign. ...

Work

Planman was one of the first individuals to make systematic astronomical observations in Finland. He made his most important observations during the

transits of Venus frameless, upright=0.5 A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a tran ...

in 1761 and 1769. The Royal Swedish Academy of Sciences provided money for expeditions to the north of Finland ( Lapland) to make the observations. The overarching aim of these expeditions was to contribute to the measurement of the

solar parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

. By participating in the expeditions and also by working with data supplied to him the academy in Stockholm, he developed a new method to calculate the parallax. His own observations in 1761 were not very precise but those made by him in 1769 were considered some of the most exact in Europe. He took an active part in the then on-going debate on whether or not Venus had an atmosphere. During the expedition in 1761, he also calculated the correct longitude for six locations on the way, among them

Kajaani Kajaani (; sv, Kajana) is the most populous town and the capital of the Kainuu Region of Finland. It is located southeast of Lake Oulu (Oulujärvi), which drains into the Gulf of Bothnia through the Oulu River (Oulujoki). As of , it had a pop ...

Mikkeli Mikkeli (; sv, S:t Michel; la, Michaelia) is a town and municipality in Finland. It is located in what used to be the province of Eastern Finland and is part of the Etelä-Savo region. The municipality has a population of () (around 34,000 ...

and

Hämeenlinna Hämeenlinna (; sv, Tavastehus; krl, Hämienlinna; la, Tavastum or ''Croneburgum'') is a city and municipality of about inhabitants in the heart of the historical province of Tavastia and the modern province of Kanta-Häme in the south of F ...

. He could do this partly because he used surveying tools for his astronomical observations; these were some of the most exact contemporary measuring tools. The minor planet 2639 Planman is named after Anders Planman.

References

{{DEFAULTSORT:Planman, Anders Finnish astronomers 1724 births 1803 deaths Uppsala University alumni 18th-century Finnish physicists Finnish mathematicians Academic staff of Uppsala University Swedish-speaking Finns Members of the Royal Society of Sciences in Uppsala