Rakke mnt 4, Simuna, 46401 Lääne-Viru County, Estonia
The point was established in 1827, located in a field and marked by a stone stele, 1.9 meters high, consisting of four parts. An informational sign is installed nearby. The KATKO point also served as a base station. To verify the location of the base stations, their coordinates were determined using GPS, and the length of the line between the markers was calculated. The difference between the distance calculated by Struve and the measured one was 13 mm, which proves the accuracy of his measurements.
The stone stele was installed by Struve’s friends Friedrich Lütke and Ferdinand Wrangel in 1849. In the book "The Pedja River," written by Helmut Junuks, it says: "Between the village of Avandus and the village of Simuna, south of the road, in a field, there is a red-gray stone pillar 1.2 meters high. From 1816 to 1855, the internationally renowned astronomer and geodesist, founder of the Tartu and Pulkovo observatories, Struve worked here. Under his leadership, an accurate measurement of the meridian arc was conducted, aimed at precisely determining the circumference and shape of the Earth. For this purpose, a vast territory from Lapland to the Danube was covered with a dense network of triangulation towers. In 1827, Struve measured a baseline 4.5 kilometers long on the plain near Simuna, one endpoint of which was in the yard of the Ilivere windmill, and the other at the site where the mentioned monument was installed in 1849."
The Struve Arc, once known as the "Russian" and later the "Russo-Scandinavian meridian arc," is one of UNESCO’s World Heritage monuments. The arc consists of 265 triangulation points, along which measurements were conducted from 1816 to 1852, enabling the precise determination of the Earth's size and shape.
The reference points of this triangulation network were marked on the ground in various ways: hollows carved into rocks, iron crosses, stone pyramids, or specially installed obelisks. Often, they were marked with sandstone bricks laid at the bottom of a pit; sometimes it was a granite cube with a cavity filled with lead, placed in a pit with cobblestones.
During the project to include the Struve Arc in the UNESCO list, which lasted 8 years, special search and geodetic work was undertaken in each country to locate the original points. All information from all the countries of the Struve Arc was collected, structured, and standardized.
Not all of the original points were found during the special search and geodetic work carried out in recent years with active cooperation from scientists of the interested countries, and many of them were found to be heavily damaged. Therefore, only the best-preserved points—34 in total—were included in the World Heritage site.
Sources:
http://www.gototrip.com/publications/geodezicheskaya-duga-struve
https://www.visitestonia.com/en/voivere-baseline-of-the-struve-arc
