Category of Astronomical Heritage: tangible immovable
Tartu Observatory, Estonia

Description

Geographical position

Old Tartu Observatory (German "Dorpat, Livland" until 1893,
Russian "Derpt" until 1893, "Jurjewskaja observatorija" until 1917), Tartu, Estonia,

New Tartu Observatory: 1963 new building in T├Áravere
(new: 58°15’55’’ N, 26°27’59’’ E)

Location

Latitude 58°22’47’’ N, Longitude 26°43’18’’ E, Elevation 48m above mean sea level.

IAU observatory code

075

Description of (scientific/cultural/natural) heritage

In 1818, Friedrich Georg Wilhelm [von] Struve (1793--1864) was appointed as professor of astronomy at the University of Dorpat, who had studied here and also made his PhD. In 1820 he took over the office of the director of the observatory. Under his leadership, Dorpat soon became one of the leading astronomical institutions. The large refractor designed by Josef Fraunhofer is the first perfect achromatic telescope with a 24-cm lens (focal length 4.33m) - the best and largest telescope of that time. Struve carried out extensive studies on binary systems. Stuve was also responsible for special tasks in Russian national surveying, including the planning and realizing of the almost 3,000 km long Struve Geodetic Arc named after him (now enlisted as a UNESCO World Heritage Site). In 1839 Friedrich Georg Wilhelm Struve moved to the newly built Pulkovo Observatory near St. Petersburg.

Fig. 1. Tartu Observatory (1810), Dorpat Observatory until 1919 (Photo: Gudrun Wolfschmidt)

In 1840 Johann Heinrich [von] Mädler (1794--1874), well-known due to his detailed drawings of the moon, which gave Mädler lasting fame with his large moon map (1834/37), took over the directorship. He continued Struve’s work, observing binary systems, and determining exact position of stars (astrometry). He undertook two expeditions to observe total solar eclipses. The first, in Brest-Litowsk (Poland) in 1860, could not be observed due to bad weather; the second, in Vitoria (Spain) in 1861, was successful.

$The 24-cm Fraunhofer refractor of Tartu Observator$

Fig. 2a. The 24-cm Fraunhofer refractor of Tartu Observatory (Photo: Gudrun Wolfschmidt)

$The 24-cm Fraunhofer refractor (1824) of Tartu Obs$

Fig. 2b. The 24-cm Fraunhofer refractor (1824) of Tartu Observatory (Photo: Gudrun Wolfschmidt)

History

Fig. 3a. Friedrich Georg Wilhelm [von] Struve (1793--1864), director from 1820 to 1839 (Jeff Struve)

Fig. 3b. Johann Heinrich [von] Mädler (1794--1874), director from 1840 to 1865 (Lithography Rudolf Hoffmann, 1856, Wikipedia)

Directors

Wilhelm Andreas Pfaff (1774--1835) - (in 1809 to Nuremberg) founder
Johann Sigismund Huth (1763--1818), 1810 to 1818
Friedrich Georg Wilhelm [von] Struve (1793--1864), 1820 to 1839
Johann Heinrich [von] Mädler (1794--1874), 1840 to 1865
Thomas Clausen (1801--1885), 1865 to 1872
Peter Carl Ludwig Eduardowitsch Schwarz (1822--1894), 1872 to 1894
Heinrich Bruns (1848--1919), 1873 to 1876
Gustav Wilhelm Ludwig von Struve (1858--1920), 1880 to 1894
Grigori Levitsky (1852--1917), 1894 to 1908
Konstantin Dorimedontowitsch Pokrovsky (1868--1944), 1908 to 1918
Taavet Rootsmäe [David Rootsman (until 1936)] (1885--1959), 1919 to 1948
Ernst Julius ├ûpik (1893--1985), famous astrophysicist in Tartu from 1921 to 1944,
(1930 to 1934 in Harvard College Observatory), Armagh Observatory, Northern Ireland, since 1948
Georgi Alexandrowitsch ┼¢elnin [Schelnin, Zhelnin] (1910--1985)
Grigori Kuzmin (1917--1988), famous astronomer
Jaan Einasto (*1929), Tartu Observatory 1977 to 1998,
Head of the Department of Cosmology; from 1992 to 1995

Fig. 3c. Ernst Julius ├ûpik (1893--1985), director in Tartu from 1921 to 1944 (Wikipedia, CC3, Martin Murphy, Armagh)

Political Changes

Dorpat (Tartu) under German leadership: 1810 to 1891

Fig. 3. Tartu Observatory (Photo: Gudrun Wolfschmidt)

By 1900, all eight directors came from Germany. Worthy of special mention are Friedrich Georg Wilhelm Struve, his grandson Ludwig von Struve and Johann Heinrich Mädler, known for his moon chart.
Derpt (until 1893), Jurjew (Tartu) under Russian leadership: 1894 to 1918:

From 1894 to 1918, there were Russian directors.
Tartu under Estonian leadership: 1919 to 1948

In 1919, Estonia became independent and Dorpat was renamed Tartu. Taavet Rootsmäe [Rootsman, David (until 1936)] (1885-1959) was the first Estonian director of the observatory, 1919 to 1948.
Jurjew (Tartu) under Russian leadership: 1948 to 1990:

In 1946, under Russian administration, the observatory was taken from the University of Tartu and given to the Estonian Academy of Sciences.
Tartu under Estonian leadership: since 1990

In 1963 a new observatory building was erected in T├Áravere.

In 1996, the old observatory was given back to the University of Tartu and was reconstructed in 2009/10 and now serves as a museum.

Fig. 4a,b. Meridian Circle, Reichenbach & Ertel of Munich (1822), 20-cm refractor, Carl Zeiss of Jena (1911), Tartu Observatory (Photo: Gudrun Wolfschmidt)

$The 24-cm-Fraunhofer refractor (1824) of Tartu Obs$

Fig. 4c. The 24-cm-Fraunhofer refractor (1824) of Tartu Observatory (Photo: Gudrun Wolfschmidt)

Instruments

7 ft Newton Reflector, Friedrich Wilhelm Herschel (1738--1822), aperture 15.9cm, focal length 214cm
Pendulum clock (sideral time), John & Myles Brockbanks (1761--1806, 1769--1821) with tubular compensation pendulum of different metals according to Troughton
8 ft Transit instrument, Dollond, aperture 4.5’’
small Transit instrument, Williams
Repetition theodolit, Wilhelm Gottlob Benjamin
Baumann (1772--1849) of Stuttgart (1806)
Pendulum clock, Brockbanks
12 ft Reflector (aperture 12’’, 26cm),
Johann Gottlieb Friedrich Schrader (1763--1832/33) of Kiel,
Anton Rospini of Petersburg (1820)
Reichenbach Meridian Circle (1822)
24-cm-Refractor, Utzschneider & Fraunhofer of Munich (1824) with clock driven gearing for rotation around the axis
Heliometer (aperture 108mm, focal length 165cm), A. Repsold & Söhne of Hamburg (1873)
Zenith telescope, A. Repsold & Söhne of Hamburg (1897)
20-cm refractor, Carl Zeiss of Jena (1911), focal length of 3m
Astrograph, Petzval (1911) with a 15-cm aperture and 78-cm focal length

Fig. 4d. Heliometer (aperture 108mm, focal length 165cm), A. Repsold & Söhne of Hamburg (1873) (Tartu Observatory)

In 1873, a Repsold heliometer was acquired -- a telescope with a divided lens for measuring smallest angular differences -- and in 1897 a zenith telescope, made by A. Repsold & Söhne of Hamburg.

In 1911, a 20-cm refractor from Carl Zeiss with a focal length of 3-m was put into operation. In the same year, an astrograph made by Petzval with a 15-cm aperture and 78-cm focal length was installed to perform astrophotography.

State of preservation

$Mounting of the Fraunhofer Refractor (Pedro Ré, 2$

Fig. 5a. Mounting of the Fraunhofer Refractor (Pedro Ré, 2008)

Fig. 5b. Tartu Observatory (Photo: Gudrun Wolfschmidt, 2011)

Fig. 5c. Tartu Observatory (credit: Tartu virtual)

Fig. 5d. Layout of Tartu Observatory (credit: Tartu virtual)

In 1996, the historical observatory building was given back to the University of Tartu and now serves as a museum.
From 2009 to 2011, the observatory building was well restored, also the famous Fraunhofer Refractor.

Fig. 5e. Tartu Observatory (Lithography August Matthias Hagen (1794--1878), 1827, Wikipedia)

Comparison with related/similar sites

Fig. 6. Dome of Tartu Observatory (Photo: Gudrun Wolfschmidt)

From the One to the Three Dome Observatory

As a typical architecture in the 19th century the rectangular observatory with a central dome was developed in addition to the cross-shaped complex. An important early example is the Tartu (Dorpat) observatory (Maegi 2009, p. 189--195) in Estonia, founded in 1802. Here, Fraunhofer’s innovative idea of introducing a clock drive for the equatorially mounted refractor in order to compensate the rotation of the earth.

The observatory on Vartiovuori Hill (1819) belonged to the Royal Academy of Turku (Åbo). The neoclassic building was designed by the German architect Carl Ludvig Engel (1778--1840), and his work also includes the observatory built later in Helsinki. During the Great Fire of Turku (1827) only the observatory and a few wooden houses were left, as Friedrich Wilhelm Argelander remarked on Sept. 4, 1827: "Hic observationes terribili illo interceptae sunt incendio, quod totam fere urbeam ad ineres reduxit, observatorium vero, gratiae habeantur Deo OM, salvum intactumque reliquit." (Here the observations were stopped by a terrible fire that burned the whole city, but, thank God, the observatory remained intact).

The Turku Academy moved the observatory and instruments to Helsinki a few years later. In 1836 the Åbo Navigationsskola (Swedish Navigation School) was moved into the empty building and stayed there until 1967; in 1998 it became a maritime and astronomical museum.

Comparable observatory buildings of the early 19th century: Naples (1820), Warsaw (1820--1824), Cape Town (1828), Christiania/Oslo (1831), Helsinki/Helsingborg (1834) and Berlin, New Observatory (1835, demolished 1915).

Threats or potential threats

no threats

Present use

Fig. 7. Struve Geodetic Arc (UNESCO)

Today the University of Tartu -- Old Observatory (Tartu Tähetorn) houses an astromical museum, public observatory with a visitor center.

Tartu Observarory is part of Struve Geodetic Arc (UNESCO, 1187), 2005.

Astronomical relevance today

The old observatory is since 1963 no longer used for modern astronomical research.
See: new Tartu observatory: Tartu Ülikool, Observatooriumi 1, T├Áravere, 61602 Tartumaa

Instruments

50cm reflector telescope (1963)
1.5-m-Cassegrain telescope (AZT-12) (1974)
0.6-m-Reflecting telescope (Zeiss 600) (1998)
0.31-m-Reflecting robotic telescope (RAITS) (2013)

Fig. 8a. New observatory in T├Áravere (*1963)

Fig. 8b. New observatory in T├Áravere (*1963) (Photo: T├Ánu Viik)

References

Bibliography (books and published articles)

Batten, Alan Henry: Resolute and Undertaking Characters: the lives of Wilhelm and Otto Struve. Dordrecht, Boston: D. Reidel Pub. (Astrophysics and Space Science Library, Bd. 139) 1988.
Eelsalu, Heino: An Attempt to draw up a List of Instruments acquired by Tartu Observatory before 1825. In: Rara Cosmographica in Estonia, Supplementum (= W. Struve nimeline Tartu Astrofüüsika Observatoorium, Teated Nr. 69), Tartu 1983, S. 8--17.
Eelsalu, Heino & Dieter B. Herrmann: Johann Heinrich Mädler (1794--1874) - Eine dokumentarische Biographie. Berlin: Akademie-Verlag 1985.
Eelsalu, Heino & H. Raudsaar: The List of Instruments and Related Objects kept in the Tartu Observatory Museum. In: Archivalia uranographica. Tartu (W. Struve nimeline Tartu Astrofüüsika Observatoorium, Teated Nr. 93) 1989, p. 4-15.
Lenz, Wilhelm (Hg.). Deutschbaltisches biographisches Lexikon 1710--1960. Köln, Wien: Böhlau 1970.
Leppik, Lea: Observatory of Tartu/Dorpat as the leading observatory in Russian Empire. In: Wolfschmidt 2018, p. 266--299.
Leue, Hans-Joachim: Johann Gottlieb Schrader und der Lilienthaler Fernrohrbau. In: Dick, Wolfgang R. & Jürgen Hamel (ed.): Astronomie von Olbers bis Schwarzschild: Nationale Entwicklungen und internationale Beziehungen im 19. Jahrhundert. Frankfurt am Main (Acta Historica Astronomiae, Bd. 14) 2002, p. 37--50.
Levitzky, Grigori: Astronomy Yur’evskago universiteta s 1802 po 1894 god [Die Astronomen der Jurjewer Universität von 1802 bis 1894]. Jurjew [Dorpat, Tartu] 1899.
Maegi, Reet: The Heritage of the 200-Year-Old University Observatory in Tartu. In: Wolfschmidt 2009, S.~188--195.
Müürseep, Peeter: Gauss and Tartu University. In: Historia Mathematica 5 (1978), p. 455-459.
Oestmann, Günther: J.W.A. Pfaff and the Rediscovery of Astrology in the Age of Romanticism. In: Oestmann, Günther: H. Darrel Rutkin & Kocku von Stuckrad (ed.): Horoscopes and Public Spheres: Essays on the History of Astrology. Berlin, New York (Religion and Society, Bd. 42) 2005, p. 241-257.
Oestmann, Günther: Zur frühen Geschichte der Dorpater Sternwarte und ihrer instrumentellen Ausstattung. In: Hamel, Jürgen & Inge Keil (Hg.): Der Meister und die Fernrohre: Das Wechselspiel zwischen Astronomie und Optik in der Geschichte. Festschrift zum 85. Geburtstag von Rolf Riekher. Frankfurt am Main (Acta Historica Astronomiae, Bd. 33) 2007, p. 315--331.
Pfaff, Johann Wilhelm Andreas: Astronomische Beobachtungen, vom Hrn. Prof. Pfaff aus Dorpat, unt. 20. Oct. 1807 eingesandt. In: Bode, Johann Elert (Hg.): Sammlung astronomischer Abhandlungen, Beobachtungen und Nachrichten. Berlin (Astronomisches Jahrbuch, Supplementband 4) 1808, S. 231-232.
Raudsepp, Marje: Wilhelm Struves Reisebericht aus dem Jahre 1820 betreffend die damalige astronomische Instrumentenkunde. In: Archivalia cosmographica (W. Struve nimeline Tartu Astrofüüsika Observatoorium, Teated, Nr. 88). Tartu 1987, S. 6-16.
Riekher, Rolf: Fernrohre und ihre Meister. Berlin: Verlag Technik GmbH 1957, (2nd edition) 1990.
Struve, Friedrich Georg Wilhelm: De geographica positione speculae astronomicae Dorpatensis. Mitau 1813.
Waaland, J. Robert: Fraunhofer and the Great Dorpat Refractor. In: American Journal of Physics 35 (1967), Issue 4, p. 344--350.
Wolfschmidt, Gudrun (ed.): Astronomie im Ostseeraum - Astronomy in the Baltic. Hamburg: tredition (Nuncius Hamburgensis; Band 38) 2018.
Wolfschmidt, Gudrun (ed.): Cultural Heritage of Astronomical Observatories -- From Classical Astronomy to Modern Astrophysics. Proceedings of International ICOMOS Symposium in Hamburg, October 14--17, 2008. Berlin: hendrik Bäßler-Verlag (International Council on Monuments and Sites, Monuments and Sites XVIII) 2009.
Zhelnin, Georgi: History of the Tartu Observatory (1805--1948). Tartu 2020. Translated by T├Ánu Viik from: Tartu Observatoorium 1805--1948. Tartu Observatooriumi Virtuaalne Muuseum 2004.