20 euros 2016 Lithuania – Coin dedicated to the Struve Geodetic Arc (UNESCO World Heritage)
20 euros proof coin with box.
Coin is made of silver (Ag 925)
Diameter – 38,61 mm
Weight– 28,28 g
Issued in 2015
What is the Struve Geodetic Arc The Struve Geodetic Arc is a triangulation measurement chain, formed in 1816-1852, stretching from the 26© east longitude along the meridian from Hammerfest (Norway) on the shores of the Arctic Ocean to Ismail (Ukraine), by the Black Sea, i.e. from 4 ©20’ to 70©40’ North latitude. The Arc covers ten states: Norway, Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Belarus, Ukraine and Moldavia. The meridian Arc length and position is calculated by the measured triangulation network fragments in the aforementioned countries. Connecting them together results in a 2,822 km-long chain, comprised of 12 sections, interspersed between astronomy points, having 10 measured bases, 258 triangles and connecting 259 triangulation
points. The average length of the sides of the triangles – 27 km, but there are sides longer than even 50 km. The diª erence of the geographical latitudes of this chain’s end points amounts to 25©20’. Until the mid-20th c. when the satellite geodetic methods were rst applied, this was the most accurately measured and longest meridian arc, for a whole century the results of its measurement were used in calculating and adjusting the parameters of the Earth’s ellipsoid.
Friedrich Georg Wilhelm von Struve (1793¬1864), professor at Tartu University and long-time head of the University’s astronomy observatory, systematised the results of the selected measurements
of the fragments of the triangulation networks for calculating the meridian’s Arc and described them in a nal report, Arc du ridien de . Based on this work by F. G. W. von Struve, in 1888 the length of the Earth’s meridian was calculated by the geodesist I. Bonsdorª .