The Struve Geodetic arc

The coin is square. The rim is raised on both sides of the coin. The edge of the coin is corrugated.

Obverse

at the top from the left side – the relief of the State Coat of Arms of the Republic of Belarus and inscription "РЭСПУБЛIКА БЕЛАРУСЬ" (REPUBLIC OF BELARUS); in the center – the planimetric plotting of Byelorussia and the circuit of points of The Struve Geodetic arc in its territory, beneath: year of issue, fine silver alloy standard,at the bottom – face value "20 РУБЛЁЎ" (20 ROUBLES) – on silver coin and "1 РУБЕЛЬ" (1 ROUBLE) – on copper–nickel coin.

Reverse

at the left – the relief image of a map of Europe on which passes The Struve Geodetic arc, on the right the image of a map of the world, under it an inscription: The Struve Geodetic arc and its extent – 2880 km, on perimeter of a coin are given names of the countries through which The Struve Geodetic arc passes: NORWAY, SWEDEN, FINLAND, ESTONIA, LATVIA, LITHUANIA, THE UKRAINE, MOLDOVA.

The Struve geodetic arc is a degree measurement of the Earth, a chain of 265 triangulation points stretching more than 2820 kilometers from the city of Hammerfest, Norway to the Black Sea coast. The measurement was carried out to determine the parameters of the Earth, its shape and size. Named after the main leader - the Russian astronomer Friedrich Georg Wilhelm Struve (Vasily Yakovlevich Struve). It was created in the territories of the Swedish-Norwegian Union and the Russian Empire in the 19th century.

scientific idea

The Struve arc on a modern political map. Red dots indicate surviving points

To confirm scientists' understanding of the shape of the Earth as a biaxial ellipsoid, measurements were taken of the meridians and the equatorial radius and compression of the Earth. A chain of 258 triangles with a common side (265 triangulation points) was laid for 2820 km (1/14 of the Earth’s circumference) from north to south along the 25-degree meridian of eastern longitude (25° 20′08″). 13 points were the main ones and were combined astronomical and geodetic points, where astronomical determinations of latitudes and azimuths were made. The leaders of the work were astronomer, academician and professor, the first director of the Pulkovo Observatory and the director of the Dorpat Observatory, the founder of the Russian Geographical Society Vasily Yakovlevich (Friedrich Georg Wilhelm) Struve and military surveyor Colonel (and then Lieutenant General) Karl Ivanovich (Karl Friedrich) Tenner.

The reference points of the meridian network were marked on the ground by hollows carved into the rocks, iron crosses, cairns or specially installed obelisks. Monuments were erected at the end points of the Arc: “Point Fuglenes” lies on the coast of the Barents Sea, not far from the North Cape and the Norwegian city of Hammerfest (70° 40′11″ north latitude), “Point Staro-Nekrasovka” is located in the Odessa region of Ukraine near the city of Izmail (45° 20′28″ north latitude).

Struve's geodetic arc was measured by scientists at the Dorpat (Tartu) and Pulkovo observatories (of which Struve was the director) for 40 years, from 1816 to 1855. Financing was carried out with funds donated personally by the emperors: Alexander I and mainly Nicholas I.

Work related to the Russian Arc was carried out under the auspices of the St. Petersburg Academy of Sciences. Measurements on the Scandinavian arc were carried out with the approval of the King of Sweden and Norway, Oscar I, by the joint forces of Swedish, Norwegian and Russian surveyors and officers with the assistance of astronomers from the Pulkovo Observatory. In 1828, the famous surveyor and cartographer, later Lieutenant General of the Russian Imperial Army, Joseph Khodzko, participated in the connection of the Lithuanian degree measurement with the Livland one, which was carried out at that time by the director of the Dorpat Observatory, Vasily Struve.

The accuracy of Struve’s measurements was very high: their verification by satellite methods in the 20th century showed an error of only 2 cm.

Significance for science

Struve's measurements were used in science and the national economy for more than 130 years; they were used in all studies of the shape of the Earth by comparing astronomical-geodetic arcs. Already in 1853-1854. Based on Russian and English (in India) measurements, Struve derived a preliminary result of calculating the most probable dimensions of the Earth, which became the very first “hit” in the history of geodetic science in the exact parameters of a common earthly biaxial ellipsoid of rotation.

The triangulation frame of degree measurements served as the basis for the creation of military topographical and navigation maps, which contributed to international contacts between scientists, military and government officials.

Currently, arc points can be found in Norway, Sweden, Finland, Russia (on the island of Gogland), Estonia, Latvia, Lithuania, Belarus, Moldova (the village of Rud) and Ukraine.

In 1993, the Finns, at a conference at the University of Tartu dedicated to the 200th anniversary of Struve, proposed giving the Duga the status of a UNESCO World Heritage Site. In Finland, all the points of the Struve Arc have been examined repeatedly since the 19th century; about six to seven dozen of them have been preserved on the territory of this country (and in Russia there are only two such points, on the island of Gogland in the Gulf of Finland, 180 km from St. Petersburg).

The proposal of Finnish scientists was included in the final resolution of the Struve anniversary conference, then supported by the International Astronomical Union and the International Federation of Geodesists. Preparation of the project to include the Struve Arc in the UNESCO list lasted 8 years. In each country, search and geodetic work was carried out to discover the initial points, information from all countries of the Struve Arc was collected, structured and brought to uniformity. Each national package of final documents was signed by a government representative. In 2004, a special International Committee was created - a supranational mechanism for managing the Struve Arc.

On 28 January 2004, a proposal to approve the surviving 34 points of the Struve Arc as a World Heritage Site was submitted to the UNESCO World Heritage Committee. In 2005, this proposal was accepted.

The basis for this was the following criteria:

huge geographical coverage. The Anglo-French and East Indian arcs are of comparable extent, but they have been measured for much longer;

accuracy of measurements;

the international nature of the research, in which scientists and cartographers from Norway, Sweden and Russia participated, the calculations of German and French mathematicians, made in Germany, are accurate