Category of Astronomical Heritage: tangible immovable
Seeberg Observatory, Germany: General Description
Format: IAU - Outstanding Astronomical Heritage
Description
Geographical position
Gotha Seeberg Observatory, Gotha, Thuringia, Germany, Elevation 406m above mean sea level.
(The transit instrument had the coordinates, also used as zero point for surveying: 50° 56′ 05″ N, 10° 43′ 51″ E)
New Gotha observatory: Jägerstraße 7, 99867 Gotha
Location
Seeberg observatory
- Lat. 50° 56′ 1.5″ N, long. 10° 43′ 41.5″ E, elevation 406m above mean sea level.
New Gotha observatory
- Lat. 50° 56′ 34.512″ N, long. 10° 42′ 30.996″ E, elevation 318.3m above mean sea level.
IAU observatory code
279
Description of (scientific/cultural/natural) heritage
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used the following instruments in his private observatory at castle Friedenstein in Gotha; it should be emphasized that all instruments were coming from London, England, was the center of instrument making in the 18th century: an 18-inch quadrant made by Sisson, London; a small 2-ft transit instrument made by Ramsden, London [DM 67751]; three Hadley sextants; an achromat heliometer made by Dollond, London [DM 67750]; a 2-ft achromat refractor made by Ramsden, London [DM 67754]; a Gregory reflector made by Short, London [Gotha] and several clocks.
Fig. 0. Seeberg observatory Gotha, around 1800 (aquarelle, Forschungs- und Landesbibliothek Gotha, Wikipedia)
Fig. 1a. Franz Xaver von Zach (1754-1832) as Major (painting by Luise Seidel, Regionalmuseum Gotha, public domain)
Fig. 1b. Ernest II (1745-1804), Duke of Saxe-Gotha-Altenburg, around 1800 (Wikipedia)
Seeberg observatory
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg. The focus of research was astrometry, time keeping, geodetic and meteorological observations. Most of the instruments came from the leading instrument makers of that time: (in brackets: place of the instrument today: "DM" - Deutsches Museum Munich (with inventory number), "Gotha" - Stiftung Schloß Friedenstein Gotha: Museum für Regionalgeschichte / Historisches Museum Gotha, "Jena" - Jena observatory): A southern and a northern quadrant; a 8-ft transit instrument made by Ramsden, London, 1788 [DM 67743 a-c]; a 7-ft Herschel reflector [DM 67483]; a 2-ft vertical circle made by Cary, London, 1796; a 8-ft circle made by Ramsden, London, 1800; a 3-ft vertical circle made by Trougthon, London, 1800; a 3-ft equatorial refractor made by Dollond, London, 1796 [DM 67745 a, b]; a 3-ft equatorial refractor made by Schroeder, Gotha [DM 67746 a, b]; a 3-ft double refractor made by Dollond, London [DM 67747]; a 10-ft refractor mady by Dollond, London, 1796; a 2-ft comet seeker made by Baumann & Kinzelbach, Stuttgart [DM 67755], sideral clock made by Arnold and the master clock made by Mudge & Dutton.
By analyzing the instrumentation, we can see around 1800 a change in the kind of the instruments on one hand from quadrants and sextants to the vertical circle and on the other hand from the transit instrument to the meridian circle. Looking to the newer equipment we recognize a general trend: The English instrument makers did no longer play an important role after the beginning of the 19th century and in contrast the German instrument makers becoming prominent.
In the 19th century the Gotha observatory acquired new instruments:
A theodolit made by Reichenbach, Utzschneider & Liebherr, München [DM 67757 a, b]; a heliometer made by Fraunhofer, München, 1817 / in the 1850s: new mounting made by Ausfeld; a 3-ft meridian circle made by Ertel, ``Utzschneider & Fraunhofer’’, München, 1826/30 [DM 67744 a, b].
For the new observatory in the town (after 1857): a 162-cm equatorial refractor (with 6-foot telescope and 2-foot circle) made by Repsold, Hamburg, optics: Steinheil, Munich, 1860, later replaced by Reinfelder & Hertel, Munich [Gotha]; a chronograph introduced for galvanic registration of transits, a 90-cm transit instrument made by Carl Bamberg, Berlin, 1912 with Repsold’s automatic recording device (unpersönlicher Registriereinrichtung) [Jena].
The only astrophysical equipment of the Gotha observatory was a Zöllner photometer made by Ausfeld, Gotha. Nothing for spectroscopy and photography could be found; this can not be only a problem of too less money. According to Strumpf (2003) the administration of Gotha missed the opportunity to introduce astrophysics and to accept the application of the wealthy Nikolaus von Konkoly, a serious amateur astronomer and one of the pioneers of astrophysics; he applied even twice.
The astronomers were still very much interested in astrometric topics, and for this purpose they got also new expensive clocks like Tiede and Riefler (siderial time clock, made by Christian Friedrich Tiede (1794-1877), Berlin, and clock made by Riefler, Munich).
In 1934 German astronomers had no success in preventing the closing of Gotha observatory. Most of the instruments went to the Deutsches Museum in Munich and some to the museum in Gotha.
History
Gotha observatory building
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used his castle Friedenstein in Gotha as a private observatory.
Fig. 2a. Footprint of Seeberg observatory Gotha ( im Catalogus Novus von 1792, Wikipedia)
Fig. 2b. Gotha observatory on the Seeberg hill (steel engraving, Wikipedia)
Seeberg observatory Gotha
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg, financed by the Duke (building 36,000 Taler, instruments 20,000 Taler; for comparison: the director got several hundreds Taler/year). The focus of research was astrometry, time keeping, geodetic and meteorological observations.
The observatory building, built by the Gotha architect and engineer Carl Christoph Besser (1724-1800), 1787-1789, was remarkable: It was a massive building, erected on sand stone in east-west direction as meridian room, which provided space for the mounting of two wall quadrants, a passage instrument and the associated pendulum clocks. The observations were to be made through slits in the wall that allowed a clear view to the north or south horizon. In the middle of the building, above the entrance hall, there was a small circular tower with a revolving dome roof - one of the earliest examples of revolving domes - in which a whole circle was to be set up. Zach had another innovative idea: he used as pillar for the instrument, the Cary circle, a strong rock fundament and thus avoided the measurement errors that resulted from oscillating components of higher buildings.
Two side wings were intended as a home of the astronomer (eastern wing) and for the staff (5 servants), the guard (one "Ordonanz", one "Sergeant" and 3 soldiers) and stables for the 4 horses (western wing). In addition there were assistants "Adjunkt", who later became famous astronomers like Johann Friedrich von Bohnenberger (1765-1831, later Tübingen), Tobias Bürg (1766-1834, later Klagenfurt and 1792 Vienna), Johann Pasquich (1753-1829), Johann Karl Burckhardt (1773-1825, later Paris military school and observatory), Johann Kaspar Horner (1774-1834, Zürich). For the rise of cartography in Gotha Bernhard August von Lindenau (1779-1834) and Adolf Stieler (1775-1826)was important.
Zach’s own description of the observatory (1789): "Das Gebäude selbst besteht aus einem länglichen Rechteck, das einen nördlichen (1) und eine südlichen (2) Haupteingang hat, dieser schneidet es in zwey Theile, davon jeder wieder in zwey Theile abgetheilt ist: in den einen kommt das Durchgangsinstrument von 8 Schuhen, mit der dazu gehörigen Pendeluhr (6), in die zweite Abtheilung wurden der südliche (4) und nördliche (5) Mauerquadrant placirt, in die dritte kommt der Zenith Sector (3). Da ich geflissentlich nirgend, wo ich die Instrumente zu stehen habe, Feuerungen oder Kamine habe anbringen wollen, so dient die 4te Abtheilung (7) zur Stube, in der man in der Winterzeit sich erholen kann, ohne erst nötig zu haben ins Wohngebäude zurückzukehren. Aus dieser Eckstube, führt eine kleine Tür unmittelbar in mein Wohngebäude... Auf der Mitte der Sternwarte erhebt sich über dem stark gewölbten Eingang, ein kleiner Thurm mit einem runden beweglichen Kuppeldach, in denselben kommt ein beweglicher ganzer 8 schuhiger Zirkel..."
Fig. 3a. Gotha Seeberg observatory - beginning of demolition (without dome), 1835 (public domain)
Fig. 3b. Ernst II monument on Seeberg (Wikipedia, Photo: Pimvantend)
The building was tumbledown after Zach’s time. In 1810 the tower was dismantled, and in 1811 the two wings. In the west of the meridian room a new dwelling for the astronomer, the assitant and the castellan was erected. In 1813 French troops damaged and distroyed the observatory building and devastated papers. Gotha was the most modern astronomical institute with respect to its instruments.
The Seeberg observatory directors were as follows:
- Franz Xaver von Zach (1754-1832), 1787-1802/06
- Bernhard von Lindenau (1780-1854), 1804-1818/20
- Johann Franz Encke (1791-1859), 1822-1825
- Peter Andreas Hansen (1795-1874), 1825-1876
Gotha’s international relationships (surveying, congres 1798, astronomical journals 1798)
Around 1800 the Gotha observatory was an international center for astronomy. Zach’s visitors were not only astronomers but e.g. Johann Wolfgang von Goethe (1749-1832) visited in 1801 the observatory; later it was used in 1829 in literature, in his "Wilhelm Meisters Wanderjahre". In 1798 the first international scientific congress took place, organized by Zach.
Franz Xaver von Zach travelled frequently to the south of France and to Italy with the Duke and Duchess of Saxe-Gotha-Altenburg (since 1786). The Duchess Marie Charlotte Amalie also worked as "computer", she made scientific calculations. They visited Marseille Observatory, Genua and erected a small observatory in Hyères; a tower of the city wall was converted into an observatory in 1787. Zach had made his first astronomical observations to determine geographical coordinates he realised that these old maps had an accuracy of at best some minutes of arc. According to Hopf & Schwarz (1998), the king of Prussia, Friedrich Wilhelm III (1797-1840), asked Zach in October 1802 to start surveying in his territories. Zach considered a land survey of Thuringia similar to the French model. His ideas were promoted by the duke Ernest II. The documents in the Forschungs- and Landesbibliothek Gotha prove that the diplomatic preparations for the survey; Zach obtained passports and grants to pass and to survey some territories (Hessen-Kassel, Hannover, Coburg-Saalfeld, Braunschweig, Sachsen). The death of Ernest II in 1804, the consequences of the war (battle of Jena and Auerstedt in 1806) and Zach’s resignation as director of the Seeberg observatory led to the end of the survey. But it was the starting point for the Prussian land surveying. As geodetic basis the measuring track was the distance from Seeberg observatory to Schwabhausen.
Why Zach is so important and we should have an interest in him today? There is a rational and an emotional answer as Brosche (2009) points out: First, he has rendered organisational services to his sciences which are equivalent to a great scientific achievement. Second, Zach was a very colourful character, travelled across many states in a time of radical changes and had connections with many colleagues and public figures.
Zach founded the first scientific astronomical journals and brought astronomers around the "world", mainly Europe at that time, in contact to each other, much easier than writing letters with astronomical results to everybody:
- Allgemeine Geographische Ephemeriden (Weimar 1798-1816), first ed. by Zach, since 1799 von Friedrich Justin Bertuch (1747--1822) and Adam Christian Gaspari (1752--1830);
- Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde (MC), Gotha 1800--1813 (28 Vol.), ed. by Zach, later by Bernhard August von Lindenau (1779--1854);
- Zeitschrift für Astronomie und verwandte Wissenschaften (ZfA), Tübingen 1816--1818 (6 Vol.), ed. by Bernhard von Lindenau and Johann Gottlieb Friedrich von Bohnenberger (1765--1831);
- Correspondance astronomique, géographique, hydrographique et statistique (CA), Genua 1818--1826 (15 Vol.), ed. by Zach.
Zach organized the first international scientific astronomical congres in 1798 together with the Paris astronomer Joseph Jérôme Lalande (1732--1807); 17 European astronomers participated: one quarter came from France, England, the Netherlands and Switzerland, the rest from the German states Prussia, Württemberg, Hannover and Saxony. New instruments, observing methods and proposals for new constellations were discussed, practical surveying on the Inselberg (916m high) were made. A critical point was the discussion about the instroduction of the new French metrical system; bacause of these revolutionary ideas some astronomers, especially from Austria, were not allowed to travel to this congres. This congres was the basis for the founduing of the first scientific astronomical society, the "Vereinigte Astronomischen Gesellschaft" (VAG) in 1800, which initiated the search for the missing planet between Mars and Jupiter; the result was the discovery of the first four asteroids.
New Gotha Observatory - From Seeberg to Town (1857/59)
In 1839 Peter Andreas Hansen decided to build a dwelling house in the center of Gotha with a small observatory (interim observatory). In 1844 Hansen made plans to transfer also the observatory to the town (in 1856 the adminitration of Gotha allwed it). He decided to dismantle the old observatory on Seeberg hill, the meridian room in 1858.
Fig. 4a. Peter Andreas Hansen (1795 in Tondern (Schleswig) - 1874 in Gotha) (Wikipedia)
Fig. 4b. Hansen’s Interim Observatory in his own house (gemeinfrei)
A new observatory was erected by the Gotha architect Gustav Eberhard (1805-1880) in the town, Jägerstrasse 7, (1857 dwelling house, 1859 observatory), which was active until 1934. Hansen was interested in the theory and errors of instruments and especially in gravitational astronomy (perturbations of Jupiter and Saturn (published in Berliner Jahrbuch) - prize of the Berlin Academy in 1830, cometary disturbances - prize of the Paris Academy in 1850), "Fundamenta nova investigationis, &c., and the improved Tables of the Moon" (Hansen’s Lunar Tables) 1838, 1857, rewarded with 1000 pounds by the British Government due to the importance for navigation (published in the Nautical Almanac in 1862), gold medal of the Royal Astronomical Society in 1842 and 1860.
Fig. 5a. New Gotha observatory (1859) (Wikipedia)
Fig. 5b. New Gotha observatory, 1995 (Photo: Strumpf, gemeinfrei)
The new Gotha observatory directors were as follows:
- Peter Andreas Hansen (1795-1874), 1860-1874, D
- Karl Nikolaus Adalbert Krueger (1832-1896), 1876-1880, D
- Hugo von Seeliger (1849-1924), 1881-1882, D
- Ernst Becker (1843-1912), 1883-1887, D
- Paul Harzer (1857-1932), 1887-1896, D
- Ernst Anding (1860-1945 ), 1906-1934, D
Vizedirector (VD), observator (O), assistant (A), administration (V):
- Friedrich Nicolai (1793-1846), 1814-1816 (later Mannheim), VD
- Johann Franz Encke (1791-1859), 1818, VD
- Leo Anton Carl de Ball (1853-1916), 1875-1878, A, V
- Ernst Jost (1861-1932 ), 1902-1904, O
- Carl Rohrbach (1861-1932), 1887-1906, V (Rohrbachturm, 1904, private observatory)
State of preservation
Gotha Seeberg Observatory, Gotha, Thuringia, Germany, Elevation 406m above mean sea level.
(The transit instrument had the coordinates, also used as zero point for surveying: 50° 56′ 05″ N, 10° 43′ 51″ E)
New Gotha observatory: Jägerstraße 7, 99867 Gotha
Location
Seeberg observatory
- Lat. 50° 56′ 1.5″ N, long. 10° 43′ 41.5″ E, elevation 406m above mean sea level.
New Gotha observatory
- Lat. 50° 56′ 34.512″ N, long. 10° 42′ 30.996″ E, elevation 318.3m above mean sea level.
IAU observatory code
279
Description of (scientific/cultural/natural) heritage
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used the following instruments in his private observatory at castle Friedenstein in Gotha; it should be emphasized that all instruments were coming from London, England, was the center of instrument making in the 18th century: an 18-inch quadrant made by Sisson, London; a small 2-ft transit instrument made by Ramsden, London [DM 67751]; three Hadley sextants; an achromat heliometer made by Dollond, London [DM 67750]; a 2-ft achromat refractor made by Ramsden, London [DM 67754]; a Gregory reflector made by Short, London [Gotha] and several clocks.
Fig. 0. Seeberg observatory Gotha, around 1800 (aquarelle, Forschungs- und Landesbibliothek Gotha, Wikipedia)
Fig. 1a. Franz Xaver von Zach (1754-1832) as Major (painting by Luise Seidel, Regionalmuseum Gotha, public domain)
Fig. 1b. Ernest II (1745-1804), Duke of Saxe-Gotha-Altenburg, around 1800 (Wikipedia)
Seeberg observatory
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg. The focus of research was astrometry, time keeping, geodetic and meteorological observations. Most of the instruments came from the leading instrument makers of that time: (in brackets: place of the instrument today: "DM" - Deutsches Museum Munich (with inventory number), "Gotha" - Stiftung Schloß Friedenstein Gotha: Museum für Regionalgeschichte / Historisches Museum Gotha, "Jena" - Jena observatory): A southern and a northern quadrant; a 8-ft transit instrument made by Ramsden, London, 1788 [DM 67743 a-c]; a 7-ft Herschel reflector [DM 67483]; a 2-ft vertical circle made by Cary, London, 1796; a 8-ft circle made by Ramsden, London, 1800; a 3-ft vertical circle made by Trougthon, London, 1800; a 3-ft equatorial refractor made by Dollond, London, 1796 [DM 67745 a, b]; a 3-ft equatorial refractor made by Schroeder, Gotha [DM 67746 a, b]; a 3-ft double refractor made by Dollond, London [DM 67747]; a 10-ft refractor mady by Dollond, London, 1796; a 2-ft comet seeker made by Baumann & Kinzelbach, Stuttgart [DM 67755], sideral clock made by Arnold and the master clock made by Mudge & Dutton.
By analyzing the instrumentation, we can see around 1800 a change in the kind of the instruments on one hand from quadrants and sextants to the vertical circle and on the other hand from the transit instrument to the meridian circle. Looking to the newer equipment we recognize a general trend: The English instrument makers did no longer play an important role after the beginning of the 19th century and in contrast the German instrument makers becoming prominent.
In the 19th century the Gotha observatory acquired new instruments:
A theodolit made by Reichenbach, Utzschneider & Liebherr, München [DM 67757 a, b]; a heliometer made by Fraunhofer, München, 1817 / in the 1850s: new mounting made by Ausfeld; a 3-ft meridian circle made by Ertel, ``Utzschneider & Fraunhofer’’, München, 1826/30 [DM 67744 a, b].
For the new observatory in the town (after 1857): a 162-cm equatorial refractor (with 6-foot telescope and 2-foot circle) made by Repsold, Hamburg, optics: Steinheil, Munich, 1860, later replaced by Reinfelder & Hertel, Munich [Gotha]; a chronograph introduced for galvanic registration of transits, a 90-cm transit instrument made by Carl Bamberg, Berlin, 1912 with Repsold’s automatic recording device (unpersönlicher Registriereinrichtung) [Jena].
The only astrophysical equipment of the Gotha observatory was a Zöllner photometer made by Ausfeld, Gotha. Nothing for spectroscopy and photography could be found; this can not be only a problem of too less money. According to Strumpf (2003) the administration of Gotha missed the opportunity to introduce astrophysics and to accept the application of the wealthy Nikolaus von Konkoly, a serious amateur astronomer and one of the pioneers of astrophysics; he applied even twice.
The astronomers were still very much interested in astrometric topics, and for this purpose they got also new expensive clocks like Tiede and Riefler (siderial time clock, made by Christian Friedrich Tiede (1794-1877), Berlin, and clock made by Riefler, Munich).
In 1934 German astronomers had no success in preventing the closing of Gotha observatory. Most of the instruments went to the Deutsches Museum in Munich and some to the museum in Gotha.
History
Gotha observatory building
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used his castle Friedenstein in Gotha as a private observatory.
Fig. 2a. Footprint of Seeberg observatory Gotha ( im Catalogus Novus von 1792, Wikipedia)
Fig. 2b. Gotha observatory on the Seeberg hill (steel engraving, Wikipedia)
Seeberg observatory Gotha
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg, financed by the Duke (building 36,000 Taler, instruments 20,000 Taler; for comparison: the director got several hundreds Taler/year). The focus of research was astrometry, time keeping, geodetic and meteorological observations.
The observatory building, built by the Gotha architect and engineer Carl Christoph Besser (1724-1800), 1787-1789, was remarkable: It was a massive building, erected on sand stone in east-west direction as meridian room, which provided space for the mounting of two wall quadrants, a passage instrument and the associated pendulum clocks. The observations were to be made through slits in the wall that allowed a clear view to the north or south horizon. In the middle of the building, above the entrance hall, there was a small circular tower with a revolving dome roof - one of the earliest examples of revolving domes - in which a whole circle was to be set up. Zach had another innovative idea: he used as pillar for the instrument, the Cary circle, a strong rock fundament and thus avoided the measurement errors that resulted from oscillating components of higher buildings.
Two side wings were intended as a home of the astronomer (eastern wing) and for the staff (5 servants), the guard (one "Ordonanz", one "Sergeant" and 3 soldiers) and stables for the 4 horses (western wing). In addition there were assistants "Adjunkt", who later became famous astronomers like Johann Friedrich von Bohnenberger (1765-1831, later Tübingen), Tobias Bürg (1766-1834, later Klagenfurt and 1792 Vienna), Johann Pasquich (1753-1829), Johann Karl Burckhardt (1773-1825, later Paris military school and observatory), Johann Kaspar Horner (1774-1834, Zürich). For the rise of cartography in Gotha Bernhard August von Lindenau (1779-1834) and Adolf Stieler (1775-1826)was important.
Zach’s own description of the observatory (1789): "Das Gebäude selbst besteht aus einem länglichen Rechteck, das einen nördlichen (1) und eine südlichen (2) Haupteingang hat, dieser schneidet es in zwey Theile, davon jeder wieder in zwey Theile abgetheilt ist: in den einen kommt das Durchgangsinstrument von 8 Schuhen, mit der dazu gehörigen Pendeluhr (6), in die zweite Abtheilung wurden der südliche (4) und nördliche (5) Mauerquadrant placirt, in die dritte kommt der Zenith Sector (3). Da ich geflissentlich nirgend, wo ich die Instrumente zu stehen habe, Feuerungen oder Kamine habe anbringen wollen, so dient die 4te Abtheilung (7) zur Stube, in der man in der Winterzeit sich erholen kann, ohne erst nötig zu haben ins Wohngebäude zurückzukehren. Aus dieser Eckstube, führt eine kleine Tür unmittelbar in mein Wohngebäude... Auf der Mitte der Sternwarte erhebt sich über dem stark gewölbten Eingang, ein kleiner Thurm mit einem runden beweglichen Kuppeldach, in denselben kommt ein beweglicher ganzer 8 schuhiger Zirkel..."
Fig. 3a. Gotha Seeberg observatory - beginning of demolition (without dome), 1835 (public domain)
Fig. 3b. Ernst II monument on Seeberg (Wikipedia, Photo: Pimvantend)
The building was tumbledown after Zach’s time. In 1810 the tower was dismantled, and in 1811 the two wings. In the west of the meridian room a new dwelling for the astronomer, the assitant and the castellan was erected. In 1813 French troops damaged and distroyed the observatory building and devastated papers. Gotha was the most modern astronomical institute with respect to its instruments.
The Seeberg observatory directors were as follows:
- Franz Xaver von Zach (1754-1832), 1787-1802/06
- Bernhard von Lindenau (1780-1854), 1804-1818/20
- Johann Franz Encke (1791-1859), 1822-1825
- Peter Andreas Hansen (1795-1874), 1825-1876
Gotha’s international relationships (surveying, congres 1798, astronomical journals 1798)
Around 1800 the Gotha observatory was an international center for astronomy. Zach’s visitors were not only astronomers but e.g. Johann Wolfgang von Goethe (1749-1832) visited in 1801 the observatory; later it was used in 1829 in literature, in his "Wilhelm Meisters Wanderjahre". In 1798 the first international scientific congress took place, organized by Zach.
Franz Xaver von Zach travelled frequently to the south of France and to Italy with the Duke and Duchess of Saxe-Gotha-Altenburg (since 1786). The Duchess Marie Charlotte Amalie also worked as "computer", she made scientific calculations. They visited Marseille Observatory, Genua and erected a small observatory in Hyères; a tower of the city wall was converted into an observatory in 1787. Zach had made his first astronomical observations to determine geographical coordinates he realised that these old maps had an accuracy of at best some minutes of arc. According to Hopf & Schwarz (1998), the king of Prussia, Friedrich Wilhelm III (1797-1840), asked Zach in October 1802 to start surveying in his territories. Zach considered a land survey of Thuringia similar to the French model. His ideas were promoted by the duke Ernest II. The documents in the Forschungs- and Landesbibliothek Gotha prove that the diplomatic preparations for the survey; Zach obtained passports and grants to pass and to survey some territories (Hessen-Kassel, Hannover, Coburg-Saalfeld, Braunschweig, Sachsen). The death of Ernest II in 1804, the consequences of the war (battle of Jena and Auerstedt in 1806) and Zach’s resignation as director of the Seeberg observatory led to the end of the survey. But it was the starting point for the Prussian land surveying. As geodetic basis the measuring track was the distance from Seeberg observatory to Schwabhausen.
Why Zach is so important and we should have an interest in him today? There is a rational and an emotional answer as Brosche (2009) points out: First, he has rendered organisational services to his sciences which are equivalent to a great scientific achievement. Second, Zach was a very colourful character, travelled across many states in a time of radical changes and had connections with many colleagues and public figures.
Zach founded the first scientific astronomical journals and brought astronomers around the "world", mainly Europe at that time, in contact to each other, much easier than writing letters with astronomical results to everybody:
- Allgemeine Geographische Ephemeriden (Weimar 1798-1816), first ed. by Zach, since 1799 von Friedrich Justin Bertuch (1747--1822) and Adam Christian Gaspari (1752--1830);
- Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde (MC), Gotha 1800--1813 (28 Vol.), ed. by Zach, later by Bernhard August von Lindenau (1779--1854);
- Zeitschrift für Astronomie und verwandte Wissenschaften (ZfA), Tübingen 1816--1818 (6 Vol.), ed. by Bernhard von Lindenau and Johann Gottlieb Friedrich von Bohnenberger (1765--1831);
- Correspondance astronomique, géographique, hydrographique et statistique (CA), Genua 1818--1826 (15 Vol.), ed. by Zach.
Zach organized the first international scientific astronomical congres in 1798 together with the Paris astronomer Joseph Jérôme Lalande (1732--1807); 17 European astronomers participated: one quarter came from France, England, the Netherlands and Switzerland, the rest from the German states Prussia, Württemberg, Hannover and Saxony. New instruments, observing methods and proposals for new constellations were discussed, practical surveying on the Inselberg (916m high) were made. A critical point was the discussion about the instroduction of the new French metrical system; bacause of these revolutionary ideas some astronomers, especially from Austria, were not allowed to travel to this congres. This congres was the basis for the founduing of the first scientific astronomical society, the "Vereinigte Astronomischen Gesellschaft" (VAG) in 1800, which initiated the search for the missing planet between Mars and Jupiter; the result was the discovery of the first four asteroids.
New Gotha Observatory - From Seeberg to Town (1857/59)
In 1839 Peter Andreas Hansen decided to build a dwelling house in the center of Gotha with a small observatory (interim observatory). In 1844 Hansen made plans to transfer also the observatory to the town (in 1856 the adminitration of Gotha allwed it). He decided to dismantle the old observatory on Seeberg hill, the meridian room in 1858.
Fig. 4a. Peter Andreas Hansen (1795 in Tondern (Schleswig) - 1874 in Gotha) (Wikipedia)
Fig. 4b. Hansen’s Interim Observatory in his own house (gemeinfrei)
A new observatory was erected by the Gotha architect Gustav Eberhard (1805-1880) in the town, Jägerstrasse 7, (1857 dwelling house, 1859 observatory), which was active until 1934. Hansen was interested in the theory and errors of instruments and especially in gravitational astronomy (perturbations of Jupiter and Saturn (published in Berliner Jahrbuch) - prize of the Berlin Academy in 1830, cometary disturbances - prize of the Paris Academy in 1850), "Fundamenta nova investigationis, &c., and the improved Tables of the Moon" (Hansen’s Lunar Tables) 1838, 1857, rewarded with 1000 pounds by the British Government due to the importance for navigation (published in the Nautical Almanac in 1862), gold medal of the Royal Astronomical Society in 1842 and 1860.
Fig. 5a. New Gotha observatory (1859) (Wikipedia)
Fig. 5b. New Gotha observatory, 1995 (Photo: Strumpf, gemeinfrei)
The new Gotha observatory directors were as follows:
- Peter Andreas Hansen (1795-1874), 1860-1874, D
- Karl Nikolaus Adalbert Krueger (1832-1896), 1876-1880, D
- Hugo von Seeliger (1849-1924), 1881-1882, D
- Ernst Becker (1843-1912), 1883-1887, D
- Paul Harzer (1857-1932), 1887-1896, D
- Ernst Anding (1860-1945 ), 1906-1934, D
Vizedirector (VD), observator (O), assistant (A), administration (V):
- Friedrich Nicolai (1793-1846), 1814-1816 (later Mannheim), VD
- Johann Franz Encke (1791-1859), 1818, VD
- Leo Anton Carl de Ball (1853-1916), 1875-1878, A, V
- Ernst Jost (1861-1932 ), 1902-1904, O
- Carl Rohrbach (1861-1932), 1887-1906, V (Rohrbachturm, 1904, private observatory)
State of preservation
Seeberg observatory
- Lat. 50° 56′ 1.5″ N, long. 10° 43′ 41.5″ E, elevation 406m above mean sea level.
New Gotha observatory
- Lat. 50° 56′ 34.512″ N, long. 10° 42′ 30.996″ E, elevation 318.3m above mean sea level.
IAU observatory code
279
Description of (scientific/cultural/natural) heritage
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used the following instruments in his private observatory at castle Friedenstein in Gotha; it should be emphasized that all instruments were coming from London, England, was the center of instrument making in the 18th century: an 18-inch quadrant made by Sisson, London; a small 2-ft transit instrument made by Ramsden, London [DM 67751]; three Hadley sextants; an achromat heliometer made by Dollond, London [DM 67750]; a 2-ft achromat refractor made by Ramsden, London [DM 67754]; a Gregory reflector made by Short, London [Gotha] and several clocks.
Fig. 0. Seeberg observatory Gotha, around 1800 (aquarelle, Forschungs- und Landesbibliothek Gotha, Wikipedia)
Fig. 1a. Franz Xaver von Zach (1754-1832) as Major (painting by Luise Seidel, Regionalmuseum Gotha, public domain)
Fig. 1b. Ernest II (1745-1804), Duke of Saxe-Gotha-Altenburg, around 1800 (Wikipedia)
Seeberg observatory
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg. The focus of research was astrometry, time keeping, geodetic and meteorological observations. Most of the instruments came from the leading instrument makers of that time: (in brackets: place of the instrument today: "DM" - Deutsches Museum Munich (with inventory number), "Gotha" - Stiftung Schloß Friedenstein Gotha: Museum für Regionalgeschichte / Historisches Museum Gotha, "Jena" - Jena observatory): A southern and a northern quadrant; a 8-ft transit instrument made by Ramsden, London, 1788 [DM 67743 a-c]; a 7-ft Herschel reflector [DM 67483]; a 2-ft vertical circle made by Cary, London, 1796; a 8-ft circle made by Ramsden, London, 1800; a 3-ft vertical circle made by Trougthon, London, 1800; a 3-ft equatorial refractor made by Dollond, London, 1796 [DM 67745 a, b]; a 3-ft equatorial refractor made by Schroeder, Gotha [DM 67746 a, b]; a 3-ft double refractor made by Dollond, London [DM 67747]; a 10-ft refractor mady by Dollond, London, 1796; a 2-ft comet seeker made by Baumann & Kinzelbach, Stuttgart [DM 67755], sideral clock made by Arnold and the master clock made by Mudge & Dutton.
By analyzing the instrumentation, we can see around 1800 a change in the kind of the instruments on one hand from quadrants and sextants to the vertical circle and on the other hand from the transit instrument to the meridian circle. Looking to the newer equipment we recognize a general trend: The English instrument makers did no longer play an important role after the beginning of the 19th century and in contrast the German instrument makers becoming prominent.
In the 19th century the Gotha observatory acquired new instruments:
A theodolit made by Reichenbach, Utzschneider & Liebherr, München [DM 67757 a, b]; a heliometer made by Fraunhofer, München, 1817 / in the 1850s: new mounting made by Ausfeld; a 3-ft meridian circle made by Ertel, ``Utzschneider & Fraunhofer’’, München, 1826/30 [DM 67744 a, b].
For the new observatory in the town (after 1857): a 162-cm equatorial refractor (with 6-foot telescope and 2-foot circle) made by Repsold, Hamburg, optics: Steinheil, Munich, 1860, later replaced by Reinfelder & Hertel, Munich [Gotha]; a chronograph introduced for galvanic registration of transits, a 90-cm transit instrument made by Carl Bamberg, Berlin, 1912 with Repsold’s automatic recording device (unpersönlicher Registriereinrichtung) [Jena].
The only astrophysical equipment of the Gotha observatory was a Zöllner photometer made by Ausfeld, Gotha. Nothing for spectroscopy and photography could be found; this can not be only a problem of too less money. According to Strumpf (2003) the administration of Gotha missed the opportunity to introduce astrophysics and to accept the application of the wealthy Nikolaus von Konkoly, a serious amateur astronomer and one of the pioneers of astrophysics; he applied even twice.
The astronomers were still very much interested in astrometric topics, and for this purpose they got also new expensive clocks like Tiede and Riefler (siderial time clock, made by Christian Friedrich Tiede (1794-1877), Berlin, and clock made by Riefler, Munich).
In 1934 German astronomers had no success in preventing the closing of Gotha observatory. Most of the instruments went to the Deutsches Museum in Munich and some to the museum in Gotha.
History
Gotha observatory building
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used his castle Friedenstein in Gotha as a private observatory.
Fig. 2a. Footprint of Seeberg observatory Gotha ( im Catalogus Novus von 1792, Wikipedia)
Fig. 2b. Gotha observatory on the Seeberg hill (steel engraving, Wikipedia)
Seeberg observatory Gotha
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg, financed by the Duke (building 36,000 Taler, instruments 20,000 Taler; for comparison: the director got several hundreds Taler/year). The focus of research was astrometry, time keeping, geodetic and meteorological observations.
The observatory building, built by the Gotha architect and engineer Carl Christoph Besser (1724-1800), 1787-1789, was remarkable: It was a massive building, erected on sand stone in east-west direction as meridian room, which provided space for the mounting of two wall quadrants, a passage instrument and the associated pendulum clocks. The observations were to be made through slits in the wall that allowed a clear view to the north or south horizon. In the middle of the building, above the entrance hall, there was a small circular tower with a revolving dome roof - one of the earliest examples of revolving domes - in which a whole circle was to be set up. Zach had another innovative idea: he used as pillar for the instrument, the Cary circle, a strong rock fundament and thus avoided the measurement errors that resulted from oscillating components of higher buildings.
Two side wings were intended as a home of the astronomer (eastern wing) and for the staff (5 servants), the guard (one "Ordonanz", one "Sergeant" and 3 soldiers) and stables for the 4 horses (western wing). In addition there were assistants "Adjunkt", who later became famous astronomers like Johann Friedrich von Bohnenberger (1765-1831, later Tübingen), Tobias Bürg (1766-1834, later Klagenfurt and 1792 Vienna), Johann Pasquich (1753-1829), Johann Karl Burckhardt (1773-1825, later Paris military school and observatory), Johann Kaspar Horner (1774-1834, Zürich). For the rise of cartography in Gotha Bernhard August von Lindenau (1779-1834) and Adolf Stieler (1775-1826)was important.
Zach’s own description of the observatory (1789): "Das Gebäude selbst besteht aus einem länglichen Rechteck, das einen nördlichen (1) und eine südlichen (2) Haupteingang hat, dieser schneidet es in zwey Theile, davon jeder wieder in zwey Theile abgetheilt ist: in den einen kommt das Durchgangsinstrument von 8 Schuhen, mit der dazu gehörigen Pendeluhr (6), in die zweite Abtheilung wurden der südliche (4) und nördliche (5) Mauerquadrant placirt, in die dritte kommt der Zenith Sector (3). Da ich geflissentlich nirgend, wo ich die Instrumente zu stehen habe, Feuerungen oder Kamine habe anbringen wollen, so dient die 4te Abtheilung (7) zur Stube, in der man in der Winterzeit sich erholen kann, ohne erst nötig zu haben ins Wohngebäude zurückzukehren. Aus dieser Eckstube, führt eine kleine Tür unmittelbar in mein Wohngebäude... Auf der Mitte der Sternwarte erhebt sich über dem stark gewölbten Eingang, ein kleiner Thurm mit einem runden beweglichen Kuppeldach, in denselben kommt ein beweglicher ganzer 8 schuhiger Zirkel..."
Fig. 3a. Gotha Seeberg observatory - beginning of demolition (without dome), 1835 (public domain)
Fig. 3b. Ernst II monument on Seeberg (Wikipedia, Photo: Pimvantend)
The building was tumbledown after Zach’s time. In 1810 the tower was dismantled, and in 1811 the two wings. In the west of the meridian room a new dwelling for the astronomer, the assitant and the castellan was erected. In 1813 French troops damaged and distroyed the observatory building and devastated papers. Gotha was the most modern astronomical institute with respect to its instruments.
The Seeberg observatory directors were as follows:
- Franz Xaver von Zach (1754-1832), 1787-1802/06
- Bernhard von Lindenau (1780-1854), 1804-1818/20
- Johann Franz Encke (1791-1859), 1822-1825
- Peter Andreas Hansen (1795-1874), 1825-1876
Gotha’s international relationships (surveying, congres 1798, astronomical journals 1798)
Around 1800 the Gotha observatory was an international center for astronomy. Zach’s visitors were not only astronomers but e.g. Johann Wolfgang von Goethe (1749-1832) visited in 1801 the observatory; later it was used in 1829 in literature, in his "Wilhelm Meisters Wanderjahre". In 1798 the first international scientific congress took place, organized by Zach.
Franz Xaver von Zach travelled frequently to the south of France and to Italy with the Duke and Duchess of Saxe-Gotha-Altenburg (since 1786). The Duchess Marie Charlotte Amalie also worked as "computer", she made scientific calculations. They visited Marseille Observatory, Genua and erected a small observatory in Hyères; a tower of the city wall was converted into an observatory in 1787. Zach had made his first astronomical observations to determine geographical coordinates he realised that these old maps had an accuracy of at best some minutes of arc. According to Hopf & Schwarz (1998), the king of Prussia, Friedrich Wilhelm III (1797-1840), asked Zach in October 1802 to start surveying in his territories. Zach considered a land survey of Thuringia similar to the French model. His ideas were promoted by the duke Ernest II. The documents in the Forschungs- and Landesbibliothek Gotha prove that the diplomatic preparations for the survey; Zach obtained passports and grants to pass and to survey some territories (Hessen-Kassel, Hannover, Coburg-Saalfeld, Braunschweig, Sachsen). The death of Ernest II in 1804, the consequences of the war (battle of Jena and Auerstedt in 1806) and Zach’s resignation as director of the Seeberg observatory led to the end of the survey. But it was the starting point for the Prussian land surveying. As geodetic basis the measuring track was the distance from Seeberg observatory to Schwabhausen.
Why Zach is so important and we should have an interest in him today? There is a rational and an emotional answer as Brosche (2009) points out: First, he has rendered organisational services to his sciences which are equivalent to a great scientific achievement. Second, Zach was a very colourful character, travelled across many states in a time of radical changes and had connections with many colleagues and public figures.
Zach founded the first scientific astronomical journals and brought astronomers around the "world", mainly Europe at that time, in contact to each other, much easier than writing letters with astronomical results to everybody:
- Allgemeine Geographische Ephemeriden (Weimar 1798-1816), first ed. by Zach, since 1799 von Friedrich Justin Bertuch (1747--1822) and Adam Christian Gaspari (1752--1830);
- Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde (MC), Gotha 1800--1813 (28 Vol.), ed. by Zach, later by Bernhard August von Lindenau (1779--1854);
- Zeitschrift für Astronomie und verwandte Wissenschaften (ZfA), Tübingen 1816--1818 (6 Vol.), ed. by Bernhard von Lindenau and Johann Gottlieb Friedrich von Bohnenberger (1765--1831);
- Correspondance astronomique, géographique, hydrographique et statistique (CA), Genua 1818--1826 (15 Vol.), ed. by Zach.
Zach organized the first international scientific astronomical congres in 1798 together with the Paris astronomer Joseph Jérôme Lalande (1732--1807); 17 European astronomers participated: one quarter came from France, England, the Netherlands and Switzerland, the rest from the German states Prussia, Württemberg, Hannover and Saxony. New instruments, observing methods and proposals for new constellations were discussed, practical surveying on the Inselberg (916m high) were made. A critical point was the discussion about the instroduction of the new French metrical system; bacause of these revolutionary ideas some astronomers, especially from Austria, were not allowed to travel to this congres. This congres was the basis for the founduing of the first scientific astronomical society, the "Vereinigte Astronomischen Gesellschaft" (VAG) in 1800, which initiated the search for the missing planet between Mars and Jupiter; the result was the discovery of the first four asteroids.
New Gotha Observatory - From Seeberg to Town (1857/59)
In 1839 Peter Andreas Hansen decided to build a dwelling house in the center of Gotha with a small observatory (interim observatory). In 1844 Hansen made plans to transfer also the observatory to the town (in 1856 the adminitration of Gotha allwed it). He decided to dismantle the old observatory on Seeberg hill, the meridian room in 1858.
Fig. 4a. Peter Andreas Hansen (1795 in Tondern (Schleswig) - 1874 in Gotha) (Wikipedia)
Fig. 4b. Hansen’s Interim Observatory in his own house (gemeinfrei)
A new observatory was erected by the Gotha architect Gustav Eberhard (1805-1880) in the town, Jägerstrasse 7, (1857 dwelling house, 1859 observatory), which was active until 1934. Hansen was interested in the theory and errors of instruments and especially in gravitational astronomy (perturbations of Jupiter and Saturn (published in Berliner Jahrbuch) - prize of the Berlin Academy in 1830, cometary disturbances - prize of the Paris Academy in 1850), "Fundamenta nova investigationis, &c., and the improved Tables of the Moon" (Hansen’s Lunar Tables) 1838, 1857, rewarded with 1000 pounds by the British Government due to the importance for navigation (published in the Nautical Almanac in 1862), gold medal of the Royal Astronomical Society in 1842 and 1860.
Fig. 5a. New Gotha observatory (1859) (Wikipedia)
Fig. 5b. New Gotha observatory, 1995 (Photo: Strumpf, gemeinfrei)
The new Gotha observatory directors were as follows:
- Peter Andreas Hansen (1795-1874), 1860-1874, D
- Karl Nikolaus Adalbert Krueger (1832-1896), 1876-1880, D
- Hugo von Seeliger (1849-1924), 1881-1882, D
- Ernst Becker (1843-1912), 1883-1887, D
- Paul Harzer (1857-1932), 1887-1896, D
- Ernst Anding (1860-1945 ), 1906-1934, D
Vizedirector (VD), observator (O), assistant (A), administration (V):
- Friedrich Nicolai (1793-1846), 1814-1816 (later Mannheim), VD
- Johann Franz Encke (1791-1859), 1818, VD
- Leo Anton Carl de Ball (1853-1916), 1875-1878, A, V
- Ernst Jost (1861-1932 ), 1902-1904, O
- Carl Rohrbach (1861-1932), 1887-1906, V (Rohrbachturm, 1904, private observatory)
State of preservation
279
Description of (scientific/cultural/natural) heritage
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used the following instruments in his private observatory at castle Friedenstein in Gotha; it should be emphasized that all instruments were coming from London, England, was the center of instrument making in the 18th century: an 18-inch quadrant made by Sisson, London; a small 2-ft transit instrument made by Ramsden, London [DM 67751]; three Hadley sextants; an achromat heliometer made by Dollond, London [DM 67750]; a 2-ft achromat refractor made by Ramsden, London [DM 67754]; a Gregory reflector made by Short, London [Gotha] and several clocks.
Fig. 0. Seeberg observatory Gotha, around 1800 (aquarelle, Forschungs- und Landesbibliothek Gotha, Wikipedia)
Fig. 1a. Franz Xaver von Zach (1754-1832) as Major (painting by Luise Seidel, Regionalmuseum Gotha, public domain)
Fig. 1b. Ernest II (1745-1804), Duke of Saxe-Gotha-Altenburg, around 1800 (Wikipedia)
Seeberg observatory
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg. The focus of research was astrometry, time keeping, geodetic and meteorological observations. Most of the instruments came from the leading instrument makers of that time: (in brackets: place of the instrument today: "DM" - Deutsches Museum Munich (with inventory number), "Gotha" - Stiftung Schloß Friedenstein Gotha: Museum für Regionalgeschichte / Historisches Museum Gotha, "Jena" - Jena observatory): A southern and a northern quadrant; a 8-ft transit instrument made by Ramsden, London, 1788 [DM 67743 a-c]; a 7-ft Herschel reflector [DM 67483]; a 2-ft vertical circle made by Cary, London, 1796; a 8-ft circle made by Ramsden, London, 1800; a 3-ft vertical circle made by Trougthon, London, 1800; a 3-ft equatorial refractor made by Dollond, London, 1796 [DM 67745 a, b]; a 3-ft equatorial refractor made by Schroeder, Gotha [DM 67746 a, b]; a 3-ft double refractor made by Dollond, London [DM 67747]; a 10-ft refractor mady by Dollond, London, 1796; a 2-ft comet seeker made by Baumann & Kinzelbach, Stuttgart [DM 67755], sideral clock made by Arnold and the master clock made by Mudge & Dutton.
By analyzing the instrumentation, we can see around 1800 a change in the kind of the instruments on one hand from quadrants and sextants to the vertical circle and on the other hand from the transit instrument to the meridian circle. Looking to the newer equipment we recognize a general trend: The English instrument makers did no longer play an important role after the beginning of the 19th century and in contrast the German instrument makers becoming prominent.
In the 19th century the Gotha observatory acquired new instruments:
A theodolit made by Reichenbach, Utzschneider & Liebherr, München [DM 67757 a, b]; a heliometer made by Fraunhofer, München, 1817 / in the 1850s: new mounting made by Ausfeld; a 3-ft meridian circle made by Ertel, ``Utzschneider & Fraunhofer’’, München, 1826/30 [DM 67744 a, b].
For the new observatory in the town (after 1857): a 162-cm equatorial refractor (with 6-foot telescope and 2-foot circle) made by Repsold, Hamburg, optics: Steinheil, Munich, 1860, later replaced by Reinfelder & Hertel, Munich [Gotha]; a chronograph introduced for galvanic registration of transits, a 90-cm transit instrument made by Carl Bamberg, Berlin, 1912 with Repsold’s automatic recording device (unpersönlicher Registriereinrichtung) [Jena].
The only astrophysical equipment of the Gotha observatory was a Zöllner photometer made by Ausfeld, Gotha. Nothing for spectroscopy and photography could be found; this can not be only a problem of too less money. According to Strumpf (2003) the administration of Gotha missed the opportunity to introduce astrophysics and to accept the application of the wealthy Nikolaus von Konkoly, a serious amateur astronomer and one of the pioneers of astrophysics; he applied even twice.
The astronomers were still very much interested in astrometric topics, and for this purpose they got also new expensive clocks like Tiede and Riefler (siderial time clock, made by Christian Friedrich Tiede (1794-1877), Berlin, and clock made by Riefler, Munich).
In 1934 German astronomers had no success in preventing the closing of Gotha observatory. Most of the instruments went to the Deutsches Museum in Munich and some to the museum in Gotha.
History
Gotha observatory building
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used his castle Friedenstein in Gotha as a private observatory.
Fig. 2a. Footprint of Seeberg observatory Gotha ( im Catalogus Novus von 1792, Wikipedia)
Fig. 2b. Gotha observatory on the Seeberg hill (steel engraving, Wikipedia)
Seeberg observatory Gotha
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg, financed by the Duke (building 36,000 Taler, instruments 20,000 Taler; for comparison: the director got several hundreds Taler/year). The focus of research was astrometry, time keeping, geodetic and meteorological observations.
The observatory building, built by the Gotha architect and engineer Carl Christoph Besser (1724-1800), 1787-1789, was remarkable: It was a massive building, erected on sand stone in east-west direction as meridian room, which provided space for the mounting of two wall quadrants, a passage instrument and the associated pendulum clocks. The observations were to be made through slits in the wall that allowed a clear view to the north or south horizon. In the middle of the building, above the entrance hall, there was a small circular tower with a revolving dome roof - one of the earliest examples of revolving domes - in which a whole circle was to be set up. Zach had another innovative idea: he used as pillar for the instrument, the Cary circle, a strong rock fundament and thus avoided the measurement errors that resulted from oscillating components of higher buildings.
Two side wings were intended as a home of the astronomer (eastern wing) and for the staff (5 servants), the guard (one "Ordonanz", one "Sergeant" and 3 soldiers) and stables for the 4 horses (western wing). In addition there were assistants "Adjunkt", who later became famous astronomers like Johann Friedrich von Bohnenberger (1765-1831, later Tübingen), Tobias Bürg (1766-1834, later Klagenfurt and 1792 Vienna), Johann Pasquich (1753-1829), Johann Karl Burckhardt (1773-1825, later Paris military school and observatory), Johann Kaspar Horner (1774-1834, Zürich). For the rise of cartography in Gotha Bernhard August von Lindenau (1779-1834) and Adolf Stieler (1775-1826)was important.
Zach’s own description of the observatory (1789): "Das Gebäude selbst besteht aus einem länglichen Rechteck, das einen nördlichen (1) und eine südlichen (2) Haupteingang hat, dieser schneidet es in zwey Theile, davon jeder wieder in zwey Theile abgetheilt ist: in den einen kommt das Durchgangsinstrument von 8 Schuhen, mit der dazu gehörigen Pendeluhr (6), in die zweite Abtheilung wurden der südliche (4) und nördliche (5) Mauerquadrant placirt, in die dritte kommt der Zenith Sector (3). Da ich geflissentlich nirgend, wo ich die Instrumente zu stehen habe, Feuerungen oder Kamine habe anbringen wollen, so dient die 4te Abtheilung (7) zur Stube, in der man in der Winterzeit sich erholen kann, ohne erst nötig zu haben ins Wohngebäude zurückzukehren. Aus dieser Eckstube, führt eine kleine Tür unmittelbar in mein Wohngebäude... Auf der Mitte der Sternwarte erhebt sich über dem stark gewölbten Eingang, ein kleiner Thurm mit einem runden beweglichen Kuppeldach, in denselben kommt ein beweglicher ganzer 8 schuhiger Zirkel..."
Fig. 3a. Gotha Seeberg observatory - beginning of demolition (without dome), 1835 (public domain)
Fig. 3b. Ernst II monument on Seeberg (Wikipedia, Photo: Pimvantend)
The building was tumbledown after Zach’s time. In 1810 the tower was dismantled, and in 1811 the two wings. In the west of the meridian room a new dwelling for the astronomer, the assitant and the castellan was erected. In 1813 French troops damaged and distroyed the observatory building and devastated papers. Gotha was the most modern astronomical institute with respect to its instruments.
The Seeberg observatory directors were as follows:
- Franz Xaver von Zach (1754-1832), 1787-1802/06
- Bernhard von Lindenau (1780-1854), 1804-1818/20
- Johann Franz Encke (1791-1859), 1822-1825
- Peter Andreas Hansen (1795-1874), 1825-1876
Gotha’s international relationships (surveying, congres 1798, astronomical journals 1798)
Around 1800 the Gotha observatory was an international center for astronomy. Zach’s visitors were not only astronomers but e.g. Johann Wolfgang von Goethe (1749-1832) visited in 1801 the observatory; later it was used in 1829 in literature, in his "Wilhelm Meisters Wanderjahre". In 1798 the first international scientific congress took place, organized by Zach.
Franz Xaver von Zach travelled frequently to the south of France and to Italy with the Duke and Duchess of Saxe-Gotha-Altenburg (since 1786). The Duchess Marie Charlotte Amalie also worked as "computer", she made scientific calculations. They visited Marseille Observatory, Genua and erected a small observatory in Hyères; a tower of the city wall was converted into an observatory in 1787. Zach had made his first astronomical observations to determine geographical coordinates he realised that these old maps had an accuracy of at best some minutes of arc. According to Hopf & Schwarz (1998), the king of Prussia, Friedrich Wilhelm III (1797-1840), asked Zach in October 1802 to start surveying in his territories. Zach considered a land survey of Thuringia similar to the French model. His ideas were promoted by the duke Ernest II. The documents in the Forschungs- and Landesbibliothek Gotha prove that the diplomatic preparations for the survey; Zach obtained passports and grants to pass and to survey some territories (Hessen-Kassel, Hannover, Coburg-Saalfeld, Braunschweig, Sachsen). The death of Ernest II in 1804, the consequences of the war (battle of Jena and Auerstedt in 1806) and Zach’s resignation as director of the Seeberg observatory led to the end of the survey. But it was the starting point for the Prussian land surveying. As geodetic basis the measuring track was the distance from Seeberg observatory to Schwabhausen.
Why Zach is so important and we should have an interest in him today? There is a rational and an emotional answer as Brosche (2009) points out: First, he has rendered organisational services to his sciences which are equivalent to a great scientific achievement. Second, Zach was a very colourful character, travelled across many states in a time of radical changes and had connections with many colleagues and public figures.
Zach founded the first scientific astronomical journals and brought astronomers around the "world", mainly Europe at that time, in contact to each other, much easier than writing letters with astronomical results to everybody:
- Allgemeine Geographische Ephemeriden (Weimar 1798-1816), first ed. by Zach, since 1799 von Friedrich Justin Bertuch (1747--1822) and Adam Christian Gaspari (1752--1830);
- Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde (MC), Gotha 1800--1813 (28 Vol.), ed. by Zach, later by Bernhard August von Lindenau (1779--1854);
- Zeitschrift für Astronomie und verwandte Wissenschaften (ZfA), Tübingen 1816--1818 (6 Vol.), ed. by Bernhard von Lindenau and Johann Gottlieb Friedrich von Bohnenberger (1765--1831);
- Correspondance astronomique, géographique, hydrographique et statistique (CA), Genua 1818--1826 (15 Vol.), ed. by Zach.
Zach organized the first international scientific astronomical congres in 1798 together with the Paris astronomer Joseph Jérôme Lalande (1732--1807); 17 European astronomers participated: one quarter came from France, England, the Netherlands and Switzerland, the rest from the German states Prussia, Württemberg, Hannover and Saxony. New instruments, observing methods and proposals for new constellations were discussed, practical surveying on the Inselberg (916m high) were made. A critical point was the discussion about the instroduction of the new French metrical system; bacause of these revolutionary ideas some astronomers, especially from Austria, were not allowed to travel to this congres. This congres was the basis for the founduing of the first scientific astronomical society, the "Vereinigte Astronomischen Gesellschaft" (VAG) in 1800, which initiated the search for the missing planet between Mars and Jupiter; the result was the discovery of the first four asteroids.
New Gotha Observatory - From Seeberg to Town (1857/59)
In 1839 Peter Andreas Hansen decided to build a dwelling house in the center of Gotha with a small observatory (interim observatory). In 1844 Hansen made plans to transfer also the observatory to the town (in 1856 the adminitration of Gotha allwed it). He decided to dismantle the old observatory on Seeberg hill, the meridian room in 1858.
Fig. 4a. Peter Andreas Hansen (1795 in Tondern (Schleswig) - 1874 in Gotha) (Wikipedia)
Fig. 4b. Hansen’s Interim Observatory in his own house (gemeinfrei)
A new observatory was erected by the Gotha architect Gustav Eberhard (1805-1880) in the town, Jägerstrasse 7, (1857 dwelling house, 1859 observatory), which was active until 1934. Hansen was interested in the theory and errors of instruments and especially in gravitational astronomy (perturbations of Jupiter and Saturn (published in Berliner Jahrbuch) - prize of the Berlin Academy in 1830, cometary disturbances - prize of the Paris Academy in 1850), "Fundamenta nova investigationis, &c., and the improved Tables of the Moon" (Hansen’s Lunar Tables) 1838, 1857, rewarded with 1000 pounds by the British Government due to the importance for navigation (published in the Nautical Almanac in 1862), gold medal of the Royal Astronomical Society in 1842 and 1860.
Fig. 5a. New Gotha observatory (1859) (Wikipedia)
Fig. 5b. New Gotha observatory, 1995 (Photo: Strumpf, gemeinfrei)
The new Gotha observatory directors were as follows:
- Peter Andreas Hansen (1795-1874), 1860-1874, D
- Karl Nikolaus Adalbert Krueger (1832-1896), 1876-1880, D
- Hugo von Seeliger (1849-1924), 1881-1882, D
- Ernst Becker (1843-1912), 1883-1887, D
- Paul Harzer (1857-1932), 1887-1896, D
- Ernst Anding (1860-1945 ), 1906-1934, D
Vizedirector (VD), observator (O), assistant (A), administration (V):
- Friedrich Nicolai (1793-1846), 1814-1816 (later Mannheim), VD
- Johann Franz Encke (1791-1859), 1818, VD
- Leo Anton Carl de Ball (1853-1916), 1875-1878, A, V
- Ernst Jost (1861-1932 ), 1902-1904, O
- Carl Rohrbach (1861-1932), 1887-1906, V (Rohrbachturm, 1904, private observatory)
State of preservation
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used the following instruments in his private observatory at castle Friedenstein in Gotha; it should be emphasized that all instruments were coming from London, England, was the center of instrument making in the 18th century: an 18-inch quadrant made by Sisson, London; a small 2-ft transit instrument made by Ramsden, London [DM 67751]; three Hadley sextants; an achromat heliometer made by Dollond, London [DM 67750]; a 2-ft achromat refractor made by Ramsden, London [DM 67754]; a Gregory reflector made by Short, London [Gotha] and several clocks.
Fig. 0. Seeberg observatory Gotha, around 1800 (aquarelle, Forschungs- und Landesbibliothek Gotha, Wikipedia)
Fig. 1a. Franz Xaver von Zach (1754-1832) as Major (painting by Luise Seidel, Regionalmuseum Gotha, public domain)
Fig. 1b. Ernest II (1745-1804), Duke of Saxe-Gotha-Altenburg, around 1800 (Wikipedia)
Seeberg observatory
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg. The focus of research was astrometry, time keeping, geodetic and meteorological observations. Most of the instruments came from the leading instrument makers of that time: (in brackets: place of the instrument today: "DM" - Deutsches Museum Munich (with inventory number), "Gotha" - Stiftung Schloß Friedenstein Gotha: Museum für Regionalgeschichte / Historisches Museum Gotha, "Jena" - Jena observatory): A southern and a northern quadrant; a 8-ft transit instrument made by Ramsden, London, 1788 [DM 67743 a-c]; a 7-ft Herschel reflector [DM 67483]; a 2-ft vertical circle made by Cary, London, 1796; a 8-ft circle made by Ramsden, London, 1800; a 3-ft vertical circle made by Trougthon, London, 1800; a 3-ft equatorial refractor made by Dollond, London, 1796 [DM 67745 a, b]; a 3-ft equatorial refractor made by Schroeder, Gotha [DM 67746 a, b]; a 3-ft double refractor made by Dollond, London [DM 67747]; a 10-ft refractor mady by Dollond, London, 1796; a 2-ft comet seeker made by Baumann & Kinzelbach, Stuttgart [DM 67755], sideral clock made by Arnold and the master clock made by Mudge & Dutton.
By analyzing the instrumentation, we can see around 1800 a change in the kind of the instruments on one hand from quadrants and sextants to the vertical circle and on the other hand from the transit instrument to the meridian circle. Looking to the newer equipment we recognize a general trend: The English instrument makers did no longer play an important role after the beginning of the 19th century and in contrast the German instrument makers becoming prominent.
In the 19th century the Gotha observatory acquired new instruments:
A theodolit made by Reichenbach, Utzschneider & Liebherr, München [DM 67757 a, b]; a heliometer made by Fraunhofer, München, 1817 / in the 1850s: new mounting made by Ausfeld; a 3-ft meridian circle made by Ertel, ``Utzschneider & Fraunhofer’’, München, 1826/30 [DM 67744 a, b].
For the new observatory in the town (after 1857): a 162-cm equatorial refractor (with 6-foot telescope and 2-foot circle) made by Repsold, Hamburg, optics: Steinheil, Munich, 1860, later replaced by Reinfelder & Hertel, Munich [Gotha]; a chronograph introduced for galvanic registration of transits, a 90-cm transit instrument made by Carl Bamberg, Berlin, 1912 with Repsold’s automatic recording device (unpersönlicher Registriereinrichtung) [Jena].
The only astrophysical equipment of the Gotha observatory was a Zöllner photometer made by Ausfeld, Gotha. Nothing for spectroscopy and photography could be found; this can not be only a problem of too less money. According to Strumpf (2003) the administration of Gotha missed the opportunity to introduce astrophysics and to accept the application of the wealthy Nikolaus von Konkoly, a serious amateur astronomer and one of the pioneers of astrophysics; he applied even twice.
The astronomers were still very much interested in astrometric topics, and for this purpose they got also new expensive clocks like Tiede and Riefler (siderial time clock, made by Christian Friedrich Tiede (1794-1877), Berlin, and clock made by Riefler, Munich).
In 1934 German astronomers had no success in preventing the closing of Gotha observatory. Most of the instruments went to the Deutsches Museum in Munich and some to the museum in Gotha.
History
Gotha observatory building
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used his castle Friedenstein in Gotha as a private observatory.
Fig. 2a. Footprint of Seeberg observatory Gotha ( im Catalogus Novus von 1792, Wikipedia)
Fig. 2b. Gotha observatory on the Seeberg hill (steel engraving, Wikipedia)
Seeberg observatory Gotha
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg, financed by the Duke (building 36,000 Taler, instruments 20,000 Taler; for comparison: the director got several hundreds Taler/year). The focus of research was astrometry, time keeping, geodetic and meteorological observations.
The observatory building, built by the Gotha architect and engineer Carl Christoph Besser (1724-1800), 1787-1789, was remarkable: It was a massive building, erected on sand stone in east-west direction as meridian room, which provided space for the mounting of two wall quadrants, a passage instrument and the associated pendulum clocks. The observations were to be made through slits in the wall that allowed a clear view to the north or south horizon. In the middle of the building, above the entrance hall, there was a small circular tower with a revolving dome roof - one of the earliest examples of revolving domes - in which a whole circle was to be set up. Zach had another innovative idea: he used as pillar for the instrument, the Cary circle, a strong rock fundament and thus avoided the measurement errors that resulted from oscillating components of higher buildings.
Two side wings were intended as a home of the astronomer (eastern wing) and for the staff (5 servants), the guard (one "Ordonanz", one "Sergeant" and 3 soldiers) and stables for the 4 horses (western wing). In addition there were assistants "Adjunkt", who later became famous astronomers like Johann Friedrich von Bohnenberger (1765-1831, later Tübingen), Tobias Bürg (1766-1834, later Klagenfurt and 1792 Vienna), Johann Pasquich (1753-1829), Johann Karl Burckhardt (1773-1825, later Paris military school and observatory), Johann Kaspar Horner (1774-1834, Zürich). For the rise of cartography in Gotha Bernhard August von Lindenau (1779-1834) and Adolf Stieler (1775-1826)was important.
Zach’s own description of the observatory (1789): "Das Gebäude selbst besteht aus einem länglichen Rechteck, das einen nördlichen (1) und eine südlichen (2) Haupteingang hat, dieser schneidet es in zwey Theile, davon jeder wieder in zwey Theile abgetheilt ist: in den einen kommt das Durchgangsinstrument von 8 Schuhen, mit der dazu gehörigen Pendeluhr (6), in die zweite Abtheilung wurden der südliche (4) und nördliche (5) Mauerquadrant placirt, in die dritte kommt der Zenith Sector (3). Da ich geflissentlich nirgend, wo ich die Instrumente zu stehen habe, Feuerungen oder Kamine habe anbringen wollen, so dient die 4te Abtheilung (7) zur Stube, in der man in der Winterzeit sich erholen kann, ohne erst nötig zu haben ins Wohngebäude zurückzukehren. Aus dieser Eckstube, führt eine kleine Tür unmittelbar in mein Wohngebäude... Auf der Mitte der Sternwarte erhebt sich über dem stark gewölbten Eingang, ein kleiner Thurm mit einem runden beweglichen Kuppeldach, in denselben kommt ein beweglicher ganzer 8 schuhiger Zirkel..."
Fig. 3a. Gotha Seeberg observatory - beginning of demolition (without dome), 1835 (public domain)
Fig. 3b. Ernst II monument on Seeberg (Wikipedia, Photo: Pimvantend)
The building was tumbledown after Zach’s time. In 1810 the tower was dismantled, and in 1811 the two wings. In the west of the meridian room a new dwelling for the astronomer, the assitant and the castellan was erected. In 1813 French troops damaged and distroyed the observatory building and devastated papers. Gotha was the most modern astronomical institute with respect to its instruments.
The Seeberg observatory directors were as follows:
- Franz Xaver von Zach (1754-1832), 1787-1802/06
- Bernhard von Lindenau (1780-1854), 1804-1818/20
- Johann Franz Encke (1791-1859), 1822-1825
- Peter Andreas Hansen (1795-1874), 1825-1876
Gotha’s international relationships (surveying, congres 1798, astronomical journals 1798)
Around 1800 the Gotha observatory was an international center for astronomy. Zach’s visitors were not only astronomers but e.g. Johann Wolfgang von Goethe (1749-1832) visited in 1801 the observatory; later it was used in 1829 in literature, in his "Wilhelm Meisters Wanderjahre". In 1798 the first international scientific congress took place, organized by Zach.
Franz Xaver von Zach travelled frequently to the south of France and to Italy with the Duke and Duchess of Saxe-Gotha-Altenburg (since 1786). The Duchess Marie Charlotte Amalie also worked as "computer", she made scientific calculations. They visited Marseille Observatory, Genua and erected a small observatory in Hyères; a tower of the city wall was converted into an observatory in 1787. Zach had made his first astronomical observations to determine geographical coordinates he realised that these old maps had an accuracy of at best some minutes of arc. According to Hopf & Schwarz (1998), the king of Prussia, Friedrich Wilhelm III (1797-1840), asked Zach in October 1802 to start surveying in his territories. Zach considered a land survey of Thuringia similar to the French model. His ideas were promoted by the duke Ernest II. The documents in the Forschungs- and Landesbibliothek Gotha prove that the diplomatic preparations for the survey; Zach obtained passports and grants to pass and to survey some territories (Hessen-Kassel, Hannover, Coburg-Saalfeld, Braunschweig, Sachsen). The death of Ernest II in 1804, the consequences of the war (battle of Jena and Auerstedt in 1806) and Zach’s resignation as director of the Seeberg observatory led to the end of the survey. But it was the starting point for the Prussian land surveying. As geodetic basis the measuring track was the distance from Seeberg observatory to Schwabhausen.
Why Zach is so important and we should have an interest in him today? There is a rational and an emotional answer as Brosche (2009) points out: First, he has rendered organisational services to his sciences which are equivalent to a great scientific achievement. Second, Zach was a very colourful character, travelled across many states in a time of radical changes and had connections with many colleagues and public figures.
Zach founded the first scientific astronomical journals and brought astronomers around the "world", mainly Europe at that time, in contact to each other, much easier than writing letters with astronomical results to everybody:
- Allgemeine Geographische Ephemeriden (Weimar 1798-1816), first ed. by Zach, since 1799 von Friedrich Justin Bertuch (1747--1822) and Adam Christian Gaspari (1752--1830);
- Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde (MC), Gotha 1800--1813 (28 Vol.), ed. by Zach, later by Bernhard August von Lindenau (1779--1854);
- Zeitschrift für Astronomie und verwandte Wissenschaften (ZfA), Tübingen 1816--1818 (6 Vol.), ed. by Bernhard von Lindenau and Johann Gottlieb Friedrich von Bohnenberger (1765--1831);
- Correspondance astronomique, géographique, hydrographique et statistique (CA), Genua 1818--1826 (15 Vol.), ed. by Zach.
Zach organized the first international scientific astronomical congres in 1798 together with the Paris astronomer Joseph Jérôme Lalande (1732--1807); 17 European astronomers participated: one quarter came from France, England, the Netherlands and Switzerland, the rest from the German states Prussia, Württemberg, Hannover and Saxony. New instruments, observing methods and proposals for new constellations were discussed, practical surveying on the Inselberg (916m high) were made. A critical point was the discussion about the instroduction of the new French metrical system; bacause of these revolutionary ideas some astronomers, especially from Austria, were not allowed to travel to this congres. This congres was the basis for the founduing of the first scientific astronomical society, the "Vereinigte Astronomischen Gesellschaft" (VAG) in 1800, which initiated the search for the missing planet between Mars and Jupiter; the result was the discovery of the first four asteroids.
New Gotha Observatory - From Seeberg to Town (1857/59)
In 1839 Peter Andreas Hansen decided to build a dwelling house in the center of Gotha with a small observatory (interim observatory). In 1844 Hansen made plans to transfer also the observatory to the town (in 1856 the adminitration of Gotha allwed it). He decided to dismantle the old observatory on Seeberg hill, the meridian room in 1858.
Fig. 4a. Peter Andreas Hansen (1795 in Tondern (Schleswig) - 1874 in Gotha) (Wikipedia)
Fig. 4b. Hansen’s Interim Observatory in his own house (gemeinfrei)
A new observatory was erected by the Gotha architect Gustav Eberhard (1805-1880) in the town, Jägerstrasse 7, (1857 dwelling house, 1859 observatory), which was active until 1934. Hansen was interested in the theory and errors of instruments and especially in gravitational astronomy (perturbations of Jupiter and Saturn (published in Berliner Jahrbuch) - prize of the Berlin Academy in 1830, cometary disturbances - prize of the Paris Academy in 1850), "Fundamenta nova investigationis, &c., and the improved Tables of the Moon" (Hansen’s Lunar Tables) 1838, 1857, rewarded with 1000 pounds by the British Government due to the importance for navigation (published in the Nautical Almanac in 1862), gold medal of the Royal Astronomical Society in 1842 and 1860.
Fig. 5a. New Gotha observatory (1859) (Wikipedia)
Fig. 5b. New Gotha observatory, 1995 (Photo: Strumpf, gemeinfrei)
The new Gotha observatory directors were as follows:
- Peter Andreas Hansen (1795-1874), 1860-1874, D
- Karl Nikolaus Adalbert Krueger (1832-1896), 1876-1880, D
- Hugo von Seeliger (1849-1924), 1881-1882, D
- Ernst Becker (1843-1912), 1883-1887, D
- Paul Harzer (1857-1932), 1887-1896, D
- Ernst Anding (1860-1945 ), 1906-1934, D
Vizedirector (VD), observator (O), assistant (A), administration (V):
- Friedrich Nicolai (1793-1846), 1814-1816 (later Mannheim), VD
- Johann Franz Encke (1791-1859), 1818, VD
- Leo Anton Carl de Ball (1853-1916), 1875-1878, A, V
- Ernst Jost (1861-1932 ), 1902-1904, O
- Carl Rohrbach (1861-1932), 1887-1906, V (Rohrbachturm, 1904, private observatory)
State of preservation
Gotha observatory building
Ernest II, Duke of Saxe-Gotha-Altenburg (1745-1804) used his castle Friedenstein in Gotha as a private observatory.
Fig. 2a. Footprint of Seeberg observatory Gotha ( im Catalogus Novus von 1792, Wikipedia)
Fig. 2b. Gotha observatory on the Seeberg hill (steel engraving, Wikipedia)
Seeberg observatory Gotha
In 1787, Franz Xaver von Zach (1754-1832) planned a new observatory outside of Gotha on the top of hill Seeberg, financed by the Duke (building 36,000 Taler, instruments 20,000 Taler; for comparison: the director got several hundreds Taler/year). The focus of research was astrometry, time keeping, geodetic and meteorological observations.
The observatory building, built by the Gotha architect and engineer Carl Christoph Besser (1724-1800), 1787-1789, was remarkable: It was a massive building, erected on sand stone in east-west direction as meridian room, which provided space for the mounting of two wall quadrants, a passage instrument and the associated pendulum clocks. The observations were to be made through slits in the wall that allowed a clear view to the north or south horizon. In the middle of the building, above the entrance hall, there was a small circular tower with a revolving dome roof - one of the earliest examples of revolving domes - in which a whole circle was to be set up. Zach had another innovative idea: he used as pillar for the instrument, the Cary circle, a strong rock fundament and thus avoided the measurement errors that resulted from oscillating components of higher buildings.
Two side wings were intended as a home of the astronomer (eastern wing) and for the staff (5 servants), the guard (one "Ordonanz", one "Sergeant" and 3 soldiers) and stables for the 4 horses (western wing). In addition there were assistants "Adjunkt", who later became famous astronomers like Johann Friedrich von Bohnenberger (1765-1831, later Tübingen), Tobias Bürg (1766-1834, later Klagenfurt and 1792 Vienna), Johann Pasquich (1753-1829), Johann Karl Burckhardt (1773-1825, later Paris military school and observatory), Johann Kaspar Horner (1774-1834, Zürich). For the rise of cartography in Gotha Bernhard August von Lindenau (1779-1834) and Adolf Stieler (1775-1826)was important.
Zach’s own description of the observatory (1789): "Das Gebäude selbst besteht aus einem länglichen Rechteck, das einen nördlichen (1) und eine südlichen (2) Haupteingang hat, dieser schneidet es in zwey Theile, davon jeder wieder in zwey Theile abgetheilt ist: in den einen kommt das Durchgangsinstrument von 8 Schuhen, mit der dazu gehörigen Pendeluhr (6), in die zweite Abtheilung wurden der südliche (4) und nördliche (5) Mauerquadrant placirt, in die dritte kommt der Zenith Sector (3). Da ich geflissentlich nirgend, wo ich die Instrumente zu stehen habe, Feuerungen oder Kamine habe anbringen wollen, so dient die 4te Abtheilung (7) zur Stube, in der man in der Winterzeit sich erholen kann, ohne erst nötig zu haben ins Wohngebäude zurückzukehren. Aus dieser Eckstube, führt eine kleine Tür unmittelbar in mein Wohngebäude... Auf der Mitte der Sternwarte erhebt sich über dem stark gewölbten Eingang, ein kleiner Thurm mit einem runden beweglichen Kuppeldach, in denselben kommt ein beweglicher ganzer 8 schuhiger Zirkel..."
Fig. 3a. Gotha Seeberg observatory - beginning of demolition (without dome), 1835 (public domain)
Fig. 3b. Ernst II monument on Seeberg (Wikipedia, Photo: Pimvantend)
The building was tumbledown after Zach’s time. In 1810 the tower was dismantled, and in 1811 the two wings. In the west of the meridian room a new dwelling for the astronomer, the assitant and the castellan was erected. In 1813 French troops damaged and distroyed the observatory building and devastated papers. Gotha was the most modern astronomical institute with respect to its instruments.
The Seeberg observatory directors were as follows:
- Franz Xaver von Zach (1754-1832), 1787-1802/06
- Bernhard von Lindenau (1780-1854), 1804-1818/20
- Johann Franz Encke (1791-1859), 1822-1825
- Peter Andreas Hansen (1795-1874), 1825-1876
Gotha’s international relationships (surveying, congres 1798, astronomical journals 1798)
Around 1800 the Gotha observatory was an international center for astronomy. Zach’s visitors were not only astronomers but e.g. Johann Wolfgang von Goethe (1749-1832) visited in 1801 the observatory; later it was used in 1829 in literature, in his "Wilhelm Meisters Wanderjahre". In 1798 the first international scientific congress took place, organized by Zach.
Franz Xaver von Zach travelled frequently to the south of France and to Italy with the Duke and Duchess of Saxe-Gotha-Altenburg (since 1786). The Duchess Marie Charlotte Amalie also worked as "computer", she made scientific calculations. They visited Marseille Observatory, Genua and erected a small observatory in Hyères; a tower of the city wall was converted into an observatory in 1787. Zach had made his first astronomical observations to determine geographical coordinates he realised that these old maps had an accuracy of at best some minutes of arc. According to Hopf & Schwarz (1998), the king of Prussia, Friedrich Wilhelm III (1797-1840), asked Zach in October 1802 to start surveying in his territories. Zach considered a land survey of Thuringia similar to the French model. His ideas were promoted by the duke Ernest II. The documents in the Forschungs- and Landesbibliothek Gotha prove that the diplomatic preparations for the survey; Zach obtained passports and grants to pass and to survey some territories (Hessen-Kassel, Hannover, Coburg-Saalfeld, Braunschweig, Sachsen). The death of Ernest II in 1804, the consequences of the war (battle of Jena and Auerstedt in 1806) and Zach’s resignation as director of the Seeberg observatory led to the end of the survey. But it was the starting point for the Prussian land surveying. As geodetic basis the measuring track was the distance from Seeberg observatory to Schwabhausen.
Why Zach is so important and we should have an interest in him today? There is a rational and an emotional answer as Brosche (2009) points out: First, he has rendered organisational services to his sciences which are equivalent to a great scientific achievement. Second, Zach was a very colourful character, travelled across many states in a time of radical changes and had connections with many colleagues and public figures.
Zach founded the first scientific astronomical journals and brought astronomers around the "world", mainly Europe at that time, in contact to each other, much easier than writing letters with astronomical results to everybody:
- Allgemeine Geographische Ephemeriden (Weimar 1798-1816), first ed. by Zach, since 1799 von Friedrich Justin Bertuch (1747--1822) and Adam Christian Gaspari (1752--1830);
- Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde (MC), Gotha 1800--1813 (28 Vol.), ed. by Zach, later by Bernhard August von Lindenau (1779--1854);
- Zeitschrift für Astronomie und verwandte Wissenschaften (ZfA), Tübingen 1816--1818 (6 Vol.), ed. by Bernhard von Lindenau and Johann Gottlieb Friedrich von Bohnenberger (1765--1831);
- Correspondance astronomique, géographique, hydrographique et statistique (CA), Genua 1818--1826 (15 Vol.), ed. by Zach.
Zach organized the first international scientific astronomical congres in 1798 together with the Paris astronomer Joseph Jérôme Lalande (1732--1807); 17 European astronomers participated: one quarter came from France, England, the Netherlands and Switzerland, the rest from the German states Prussia, Württemberg, Hannover and Saxony. New instruments, observing methods and proposals for new constellations were discussed, practical surveying on the Inselberg (916m high) were made. A critical point was the discussion about the instroduction of the new French metrical system; bacause of these revolutionary ideas some astronomers, especially from Austria, were not allowed to travel to this congres. This congres was the basis for the founduing of the first scientific astronomical society, the "Vereinigte Astronomischen Gesellschaft" (VAG) in 1800, which initiated the search for the missing planet between Mars and Jupiter; the result was the discovery of the first four asteroids.
New Gotha Observatory - From Seeberg to Town (1857/59)
In 1839 Peter Andreas Hansen decided to build a dwelling house in the center of Gotha with a small observatory (interim observatory). In 1844 Hansen made plans to transfer also the observatory to the town (in 1856 the adminitration of Gotha allwed it). He decided to dismantle the old observatory on Seeberg hill, the meridian room in 1858.
Fig. 4a. Peter Andreas Hansen (1795 in Tondern (Schleswig) - 1874 in Gotha) (Wikipedia)
Fig. 4b. Hansen’s Interim Observatory in his own house (gemeinfrei)
A new observatory was erected by the Gotha architect Gustav Eberhard (1805-1880) in the town, Jägerstrasse 7, (1857 dwelling house, 1859 observatory), which was active until 1934. Hansen was interested in the theory and errors of instruments and especially in gravitational astronomy (perturbations of Jupiter and Saturn (published in Berliner Jahrbuch) - prize of the Berlin Academy in 1830, cometary disturbances - prize of the Paris Academy in 1850), "Fundamenta nova investigationis, &c., and the improved Tables of the Moon" (Hansen’s Lunar Tables) 1838, 1857, rewarded with 1000 pounds by the British Government due to the importance for navigation (published in the Nautical Almanac in 1862), gold medal of the Royal Astronomical Society in 1842 and 1860.
Fig. 5a. New Gotha observatory (1859) (Wikipedia)
Fig. 5b. New Gotha observatory, 1995 (Photo: Strumpf, gemeinfrei)
The new Gotha observatory directors were as follows:
- Peter Andreas Hansen (1795-1874), 1860-1874, D
- Karl Nikolaus Adalbert Krueger (1832-1896), 1876-1880, D
- Hugo von Seeliger (1849-1924), 1881-1882, D
- Ernst Becker (1843-1912), 1883-1887, D
- Paul Harzer (1857-1932), 1887-1896, D
- Ernst Anding (1860-1945 ), 1906-1934, D
Vizedirector (VD), observator (O), assistant (A), administration (V):
- Friedrich Nicolai (1793-1846), 1814-1816 (later Mannheim), VD
- Johann Franz Encke (1791-1859), 1818, VD
- Leo Anton Carl de Ball (1853-1916), 1875-1878, A, V
- Ernst Jost (1861-1932 ), 1902-1904, O
- Carl Rohrbach (1861-1932), 1887-1906, V (Rohrbachturm, 1904, private observatory)