Tag Archives: astronomer

Struve Geodetic Arc part 2

I am sorry to say that I had to cancel, or postpone, my trip to the survey point at Alanen Perävaara due to the weather.

As I wrote in my previous post the Struve Arc is a chain of survey triangulations points. It stretches from Hammerfest in Norway to the Black Sea and covers more than 2,800 km. The world heritage is made up by 34 of the original 265 survey points of which four are in Sweden on the mountains Tynnyrilaki, Jupukka, Pullinki, and Perävaara in the municipalities Haparanda, Kiruna, Pajala and Övertorneå in Tornedalen. The Struve Arc was made a UNESCO world heritage in 2005.

In the beginning of 19th century the German-Russian astronomer Wilhelm von Struve (1793-1864) decided to triangulate the exact form and size of the Earth. The survey was carried out between 1816 and 1855. All in all he used 265 measure points 30 km apart from each other, from in Hammerfest Norway to Izmail at the Black Sea. The measurements proved that the latitudes were ca ten meter less wide in Scandinavia than at the equator, thus proving that the Earth was oval rather than round. The project started in Russia 1816, in Sweden it started in the 1840’s and was finally finishes at the Pulkovo observatory where the finishing calculations where made.

Struve’s measurement wasn’t the first attempt to investigate whether the earth was oval or round; in 1745 the royal French academy of sciences sent an expedition to Peru and another to the Sweden led by in De Maupertuis. The expedition came to Tornedalen (Torne valley) in 1736 and included among others Anders Celsius and was finished in 1737. Jöns Svanberg during continued the work during 1800-1804.

Magnus Reuterdahl

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