Gotha - the instruments of the observatory

Around 1800 the Gotha observatory was an international center of astronomy and was the most modern astronomical institute with respect to its instruments 1. Duke Ernst II of Sachsen-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 2: A 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. 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 36000 Taler, instruments 20000 Taler; for comparison: the director got several hundreds Taler/year). 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: 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]. 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)3: a 162-cm equatorial refractor made by Repsold, Hamburg, 1860 [Gotha]; a 90-cm transit instrument made by C. Bamberg, Berlin, 1912 [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. The astronomers were very much interested in astrometric topics, and for this purpose they got also new expensive clocks like Tiede and Riefler. 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.