Tartu Observatory
Encyclopedia
The Tartu Observatory is the largest astronomical
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 observatory
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...

 in Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

. It is located on the Tõravere
Tõravere
Tõravere is a small borough in Nõo Parish, Tartu County, Estonia. Tartu Observatory is located in Tõravere.-External links:*...

 hill, about 20 km south-west of Tartu
Tartu
Tartu is the second largest city of Estonia. In contrast to Estonia's political and financial capital Tallinn, Tartu is often considered the intellectual and cultural hub, especially since it is home to Estonia's oldest and most renowned university. Situated 186 km southeast of Tallinn, the...

 in Nõo Parish
Nõo Parish
-Settlements:Small boroughs:Nõo - TõravereVillages:Aiamaa - Altmäe - Etsaste - Enno - Illi - Järiste - Kääni - Keeri - Ketneri - Kolga - Laguja - Luke - Meeri - Nõgiaru - Sassi - Tamsa - Unipiha - Uuta - Vissi - Voika-External links:...

, Tartu County
Tartu County
Tartu County , or Tartumaa , is one of 15 counties of Estonia.It is located in eastern Estonia bordering Põlva County, Valga County, Viljandi County and Jõgeva County....

. The old Tartu Observatory is known internationally for its connection to Friedrich Georg Wilhelm von Struve
Friedrich Georg Wilhelm von Struve
Friedrich Georg Wilhelm von Struve was a Danish-Baltic German astronomer from a famous dynasty.-Life:...

 and the Struve Geodetic Arc
Struve Geodetic Arc
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....

, of which it is the first reference point.

History

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
Joseph von Fraunhofer
Joseph von Fraunhofer was a German optician. He is known for the discovery of the dark absorption lines known as Fraunhofer lines in the Sun's spectrum, and for making excellent optical glass and achromatic telescope objectives.-Biography:Fraunhofer was born in Straubing, Bavaria...

 refractor arrived, the largest achromatic telescope
Achromatic telescope
The achromatic telescope is a refracting telescope that uses an achromatic lens to correct for chromatic aberration.-How it works:When an image passes through a lens, the light is refracted at different angles for different wavelengths. This produces focal lengths that are dependent on the color of...

 in the world at the time. When von Struve began assembling his Geodetic Arc
Struve Geodetic Arc
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....

 in 1816, the doorstep of the observatory became its first point.

In 1946 the renamed Tartu Observatory was separated from the university and subjected to the Estonian Academy of Sciences
Estonian Academy of Sciences
Founded in 1938, the Estonian Academy of Sciences is Estonia's national academy of science. As with other national academies, it is an independent group of well-known scientists whose stated aim is to promote research and development, encourage international scientific cooperation, and...

. The authorities started to look for the new observational base in 1950. A patch of land on the Tõravere hill was assigned for the purpose and in 1958 construction began. By 1963, the new observatory building was completed, part of the astronomers from the old observatory moved in, and the 50 cm reflector telescope had first light. In 1964, an international conference was held and the Tartu Observatory was renamed von Struve Observatory. In 1974 the 1.5 metre telescope become operational. The name of the observatory was reverted back to Tartu Observatory in 1995. In 1998, a 0.6 metre reflector was installed, the last major instrument update for today. The old observatory building now mainly serves as a museum and is a part of a public science education centre.

Several notable scientists have been associated with the Tartu Observatory: von Struve, Johann Heinrich von Mädler
Johann Heinrich von Mädler
Johann Heinrich von Mädler was a German astronomer.He was orphaned at age 19 by an outbreak of typhus, and found himself responsible for raising three younger sisters...

, Thomas Clausen
Thomas Clausen (mathematician)
Thomas Clausen was a Danish mathematician and astronomer....

, Ernst Julius Öpik, Grigorij Kuzmin
Grigorij Kuzmin
Grigorij Kuzmin is a notable Estonian astronomer who worked mainly in the field of stellar dynamics.-External links:**...

, Jaan Einasto
Jaan Einasto
Jaan Einasto is an eminent Estonian astrophysicist and one of the discoverers of the cellular structure of the Universe....

.

Equipment

The observatory has two main telescopes. The 1.5 metre Cassegrain reflector
Cassegrain reflector
The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas....

, which is the largest optical telescope in Northern Europe
Northern Europe
Northern Europe is the northern part or region of Europe. Northern Europe typically refers to the seven countries in the northern part of the European subcontinent which includes Denmark, Estonia, Latvia, Lithuania, Norway, Finland and Sweden...

, is used for spectroscopic observations. The second telescope is a 0.6 metre reflector for photometric
Photometry (astronomy)
Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation...

 observations. There is also a pitch for a collection of meteorological
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...

 instruments on the observatory grounds.

External links

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