Strūves ģeodēziskais loka punkts BRISTEN

Strūves ģeodēziskais loka punkts BRISTEN/ Struve Geodetic Arc point BRISTEN / Геодезический пункт Струве BRISTEN LV

LV 2005. gadā Strūves loks iekļauts UNESCO Pasaules mantojuma sarakstā kā unikāla garākā un precīzākā ģeodēzisko uzmērījumu sistēma.

EN In 2005, the circle of Struves was included in the UNESCO World Heritage List as a unique system for the longest and most accurate geodesic measurements of the 19 th century.

RU В 2005 году геодезический пункт Струве включён во Всемирное наследие ЮНЕСКО, как уникальная, самая протяжённая и точная система геодезического измерения, как наивысшее достижение своего времени, свидетельство развития истории и техники.

B RIS TEN     (B RIS TENE)            –           S TRŪVE S    ĢE ODĒ ZISKĀ        L OKA            PUNKT S       UN            LA UKA         OB SER V AT ORIJ A


Bristen – station point of Struve geodetic arc an field observatory.

The Struve Arc is a chain of survey triangulations stretching from Hammerfest in Norway, through Terbata (nowadays Tarty in Estonia) to town of Izmail on the coast of the Black Sea, through 10 countries and over 2,820 km.

These are points of a survey, carried out between 1816 and 1855. This chain of triangles covers a long segment of 26th meridian.

In contemporary geopolitical map Struve geodetic arc crosses 10 countries: Norway, Finland, Russia, Estonia, Latvia, Lithuania, Belarus, Moldova and Ukraine.

Measured arc of meridian covers 25° 20´ of Earth’s circumference.

The Struve geodetic arc consisted of 258 main triangles with 265 main station points and 60 auxiliary points. 13 points had been used as connected geodetic astronomy points. The distance between points varies from 30 to 40 km.

The astronomer Friedrich Georg Wilhelm Struve, and Carl Friedrich Tenner carried out the measurements, on order of Russian Tsar. On the territory of Latvia 16 geodetic points were established – Struve built eleven of those, but Tenner – five. Two of those 16 Latvian points are connected geodetic astronomy points: Jacobstadt and Bristen. F.G.Struve carried out observations in point “Jacobstadt”, that was the Southern end-point of Baltic arc. K.F.Tenner carried out observations in point “Bristen”, which was the Northern point of Lithuanian arc. The layout of those points allowed to combine Baltic and Lithuanian arcs.

F.G.V.Struve used measurement units called “French toise” while K.F. Tenner used unit of measurement called “fathom” or “sazhen”. Both scientists met in Tartu (Estonia) in January 1828 and signed an agreement protocol for joining the Baltic and Lithuanian arc measurements and further cooperation due south and north.

“Toise” – French measurement unit of length, that was used till implementation of metrical system.

“Sazhen or fathom” – Russian measurement unit of length used in the middle of 17th century till implementation of metrical system.

1 tuaze (toise) = 1,949 metri

1 sazhen/fathom (сажень) = 2,1336 metri

The Struve Arc represented the first accurate measuring of a long segment of a meridian. This helped to establish the exact size and shape of the planet and marked an important step in the development of earth sciences and topographic mapping. It is an extraordinary example of scientific collaboration among scientists from different countries, and of collaboration between monarchs for a scientific cause. The original arc consisted of 258 main triangles with 265 main station points

In 2005, the Struve Geodetic Arc was accepted into the UNESCO World Heritage List as a unique, longest and most precise system of geodetic measurement of its time. It is an outstanding example of international collaboration and development of science and technologies, using especially designed instruments and tools. The Struve Geodetic Arc represents the cultural heritage of science and technology.

The listed Unesco World Heritage site includes 34 of the original station points in 10 countries, with different markings, i.e. a drilled hole in rock, iron cross, cairns, or built obelisks

There are two Struve geodetical arc points in Latvia that are listed in UNESCO World Heritage List – Jacobstadt (Jekabpils) and Sestu hill (Sestu/Ziestu kalns).

Coordinates of point Bristen (System LKS-92)

x 271604,46

y 583510,14

B 56° 34’ 52,60”

L 25° 21’ 34,27”

Location: Sece parish, Jaunjelgava municipality

In order to preserve destination point of Lithuanian arc named “Bristen”, thorough reconstruction works have been done. Workers dug a large base hole with volume of 2,13 m3 that was filled with dolomite stone masonry. They placed a 10 inch (0,25 m) granite cube in the centre of hole, in the middle of that cube a lead has been poured in the form of cylinder in depth of 5 inches (0,13 m) with radius of ¾ inches (0,02m). The centre of the cylinder was marked with two crossing lines. In order to establish a certain position of the centre of point, four bricks were laid on top of it. After measurements were done, the point was covered with boulders and soil, later the centre of point was posed upwards .

To do precise measurements, a 7 meters tall triangulation signal has been built, as during the 19th century the area of Bristen was clear from trees and there was no higher hill on South of observatory, but on North the highest points were Ziestu/Sestu hill (217,46 m) and Gaizins ( Gaiziņkalns) (311,12 m).

The observations from point Bristen were made to 4 points: Ziestu/Sestu hill, Dabors hill, Arbidani and Daudsewas (Daudzeva) hill. The observations were made under supervision of C.F.Tenner and I.I.Hodzjko.

Second class trigonometrical network point “Greblukalns”.

During exploration works of Bristen field observatory, top centre of triangulation point Greblukalns was found. The point was established in 1926. During those years, the triangulation networks were made and measurements were done by employees of Land (later Agriculture and Land establishment) departments’ Land surveying unit from Ministry of Agriculture.  Nowadays the centre of the top point is not located on its original place.

The establishment of I and II class trigonometrical network has been done according to the projects of Land surveying unit. In certain way all the signals are similar to each other. Meaning, that each signal consists from two completely separate and isolated pyramids.

The inner pyramid finishes with  table for survey tools, the outer – observation part  with built in observation platform, reaches higher and completes with an observation cylinder and separately designed observation sign.

The centres of the second-class signals were reinforced by positioning two signs – on the ground and underground. Those signs were specially made weather from concrete or local boulders in order to avoid dispositioning and damaging of signs. The height of Greblukalns signal was 26, 5 m.

Information from historical overviews “Latvian trigonometrical network, Riga, 1922.-1938.”

Astronomical observatory was established in spring of 1826, the trigonometrical point Bristen in 1828, as it is marked by a number engraved on a point.

Observatory Bristen was a small wooden building on stable base made from dolomite. There was a separate base for floor and positioning of clock. The field observatory was equipped  with Ramsdens’ theodolite, positioned from East to West and Sheltons’ astronomical clock. The geographical latitude of first vertical, using 5 ½ feet Ramsden theodolite was determined in observatory. 100 feet further from field observatory a temporary building for 15 people was built to maintain full time security for the observatory. The point was located approximately 1,794 sazhens (fathoms) (3,80 m) from the centre of Ramsdens’ theodolite.

Carl Friedrich Tenner

 (1783 – 1859)

Carl Friedrich Tenner was born on 22nd of June 1783. in  Viru, Estonia, in poor family of the manager of Auvere manor, that could not support good education to their son.

In 1795, surveying works took part in Estonia and the first contact with it awakes interest in drawing and technical drawing to C.F.Tenner. It was noticed by count Gotthard A.von Mannteuffel who further supported the education of young Tenner. He learns mathematics, French, German and Latin languages, history, geography, music.

In 1798, Count von Mannteuffel orders to Tenner to make a map as an annex to description of Siberia and Middle Asia.

In 1801, Tenner draw attention of Russian general Suhtelen and was enlisted in military service.

In 1803, took part in a diplomatic mission to China lead by Count Golovkin,  drawing maps and doing surveys during trip.

In 1807, took part in battles with French army, receives several high awards – order of St.Vladimir small-sword of Anna and Prussian order.

In 1808, Tenner returned to the Map Depot in St Petersburg where he started to work on the maps compiled during the trip to Siberia and the respective atlas was published in 1809. At the same time, he renewed attending the astronomical lectures by Shubert

In 1809 Tenner together with two other officers was given a task to map the area of St Petersburg and then the regions close to the southern coast of the Gulf of Finland and the islands in it.

In 1812. Tenner took part in war with Napoleon. He was given three orders for chivalry – one them was the Cross of St George of the 4th degree. This order was given only for personal valour. Tenner received also a golden sword with the inscript “For bravery” (it shoud be said here that Tenner received also the Prussian order “Pour le Mérite”. He also was promoted to colonel’s rank and then finished his military career.

In 1816. – 1822, Tenner was given a task to do the triangulation of Vilnius, Kurland and Grodno regions.

In 1819. – 1829, adding extra astronomical surveys, complete geodetic survey of Vilnius has been done, using menzula.

In 1830. – 1844, Tenner goes further to South from Vilnius – to Pripyat river and Ukraine

In 1832., 1843 and 1852,  leads three continental triangulation conjunctions with Prussian, Austrian and British triangulation networks.

Since 1832 C.F.Tenner is a member of honour of Academy of Sciences of St. Petersburg.

In 1846. – 1850, continues surveys in Bessarabia to Fort Ismail at the Creek of Danube River

On 28th of December 1859 Carl Friedrich Tenner dies at age of 76 in Warsaw, Poland.

Friedrich Georg Wilhelm Struve

Friedrich Georg Wilhelm Struve was born on 15th of April 1793 in Altona by Hamburg, Germany.

In 1808, entered the University of Terbata (Tartu) in faculty of philology that he graduated with a golden medal in 1811. In 1812, Struve was arrested as he did experimental surveys using Troughton sextant, which he bought by saved money. Military thought that Struve was a spy and the case was solved in military court in Parnu.

Field Observatory

In 1813, Struve got a doctors’ degree for determination of geographical coordinates of Terbata (Tartu) observatory.

In 1816, on demand of Livonian economic society begun a geodetic survey project in order to draw a topographic map of Livonia

In 1818, Struve become a professor of Terbata (Tartu) University

In 1819, Struve has the necessary funds for equipment of observatory in order to perform degree measurements In 1820, he became a director of Terbata (Tartu) observatory

In 1822, Struve became a member of Academy of Sciences of St. Petersburg but  in 1826 promoted to a member of honour. Beginning with 1824, at the age of 25 Struve taught officers and military geodetics to  perform astronomic and geodetic works.

In 1827 on 25th anniversary of Terbata (Tartu) university Struve presented the results of research on Baltic geodetic arc.

In 1831 He was nominated as an Adviser of Russian empire and was given a status of noble man, since that his second name was “von Struve”

In 1832, Stuve was elected to Russian Academy of Sciences.

In 1839 He became a director of newly established Pulkovo observatory and in  1845 he took part in establishing a Russian Geographical society.

In 1856, Russian emperor nominated Struve as a secret advisor of empire.  In 1863  Struve celebrated 50th anniversary in science.

He died on 23rd of November 1864 at age of 71 and is buried in the cemetery near Pulkovo observatory.

Informative material was created by Latvian Geospatial Information Agency in collaboration with Jaunjelgava municipality Latvian National Commission for UNESCO

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