#229 Estonia

Postal Stationery No. 67. Date: December 22, 2010.

The Tartu Observatory (Estonian: Tartu Observatoorium) is the largest astronomical observatory in Estonia. It is located on the Tõravere hill, about 20 km south-west of Tartu in Nõo Parish, Tartu County. The old Tartu Observatory is known internationally for its connection to Friedrich Georg Wilhelm von Struve and the Struve Geodetic Arc, of which it is the first reference point.

The Tartu Observatory was founded at the Imperial University of Dorpat as it was reopened in 1802. The observatory building was completed in 1810 on the Toome hill in Dorpat. The instruments were installed in 1814 by von Struve who subsequently started observations. In 1824, a 9" Fraunhofer refractor arrived, the largest achromatic telescope in the world at the time. When von Struve began assembling his Geodetic Arc in 1816, the doorstep of the observatory became its first point.
 Wikipedia.org 

The Struve Geodetic Arc is a chain of survey triangulations stretching from Hammerfest in Norway to the Black Sea, through ten countries and over 2,820 km, which yielded the first accurate measurement of a meridian.

The chain was established and used by the German-born Russian scientist Friedrich Georg Wilhelm von Struve in the years 1816 to 1855 to establish the exact size and shape of the earth. At that time, the chain passed merely through two countries: Union of Sweden-Norway and the Russian Empire. The Arc's first point is located in Tartu Observatory, where Struve conducted much of his research.

In 2005, the chain was inscribed on the World Heritage List as a memorable ensemble of the chain made up of 34 commemorative plaques or built obelisks out of the original 265 main station points which are marked by drilled holes in rock, iron crosses, cairns, others.

Measurement of the triangulation chain comprises 258 main triangles and 265 geodetic vertices. The northernmost point is located near Hammerfest in Norway and the southernmost point near the Black Sea in Ukraine. This inscription is located in ten countries, the most of any UNESCO World Heritage.
Wikipedia.org

Property No #1187

Date of Inscription on the List of UNESCO: 2005

Sent on: April 8, 2013

Received on: April 9, 2013