TARTU OLD OBSERVATORY
Location: N58° 22` 43.6", E26° 43` 12.4" | Website: tahetorn.ut.ee/en
The University of Tartu, founded by Gustav II Adolf, the King of Sweden, in 1632, didn't have a separate observation tower, nonetheless astronomy was practised. The university's first telescope was bought by one forward-looking professor of mathematics who ordered it from England. It was supposedly an about six-metre-long refractor telescope with tubes that fit into each other. In 1802 , when the Tsarist Russian government reopened the university, the construction works of an observatory started upon the ruins of an old episcopal castle. The heyday of the Observatory began with the arrival of Friedrich Georg Wilhelm von Struve. He set up the observatory which was completed by 1810 and ordered some instruments; for example, the world's best telescope at that time – the 9-inch Fraunhofer Refractor. Struve's contribution to the astronomy is so-called Struve Geodetic Arc, which helped to determine the exact size and shape of the Earth. This work allowed improvements in navigation and more accurate mapping. As a result of his observations, he found more the 3,000 double stars and was the first in the world to measure the parallax of a star and calculate its distance from the Earth. Tartu became the the most important observatory of the Russian Empire. Tsar Alexander I invited Struve to run a fancier observatory to be built in St. Petersburg. Struve was succeeded by Johann Heinrich Mädler who had gained fame with his Moon maps. At the beginning of 20th century the earthquakes were researched in Tartu.
However, Ernst Julius Öpik became the brightest star of the observatory. He was the first in the world to determine the distance of the Andromeda Galaxy, proving that this is an independent galaxy not a star cluster within our galaxy. Öpik also worked out a method of counting meteors and he was invited to Harvard University to introduce it. The relationships made in Harvard rescued him from the refugee camp in Germany during World War II and let him work at the Armagh Observatory in Northern Ireland almost until his death.
During the Soviet era the observation tower was managed by The Academy of Sciences of Estonian Soviet Socialist Republic (ESSR). With the beginning of Space Age, astronomy was declared a priority and the new observatory was established in Tõravere. The old observatory was given back to Tartu University in 1996. In 2011, the museum was opened in the observation tower. Visitors can explore a varied permanent exposition of astronomy and space exploration, the world's best telescope, Islamic Celestial Globe, count falling meteors and learn about constellations.