Joseph Liesganig

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Monument at the Neustadt end point of the base route ( Liesganigstein )

Joseph Liesganig (born February 13, 1719 in Graz , † March 4, 1799 in Lemberg , Galicia ) was an Austrian Jesuit , theologian and astronomer . Under Maria Theresa he made a decisive contribution to land surveying and metrology .

In 1752 Father Liesganig became a mathematics professor at the University of Vienna . 1756-1773 he served as the successor of Father Joseph Francis , the Jesuits observatory Vienna at the former University of Vienna, in the resolution of the Jesuit College in 1773 Vienna Observatory opened. In 1761 and 1767 he observed the phenomenon of the passage of Venus from Vienna.

Liesganig, along with Rugjer Josip Bošković and Lemaine, is one of those scientifically active Jesuits who dealt intensively with the study of the earth figure . As early as 1757 it determined the height of Vienna's pole with its 10-foot zenith sector . From 1761–1765, on behalf of Empress Maria Theresa, he was in charge of measuring the degree in the Vienna Meridians , where a 320 km long meridian arc was measured from Brno via Vienna to Varasdin . From 1766 to 1769 he was commissioned to survey the Hungarian reference meridian. Larger surveying projects by Josef Liesganig were also carried out in Galicia and Styria .

As a basis for the triangulation , Liesganig chose a route between Wiener Neustadt and Neunkirchen , which is known today as the Wiener Neustadt baseline . For the measurement, a lane was cleared through the pine forest, which was then used for the construction of Neunkirchner Allee , which explains the dead straight course of the avenue. The case used precision scale of 2 feet in length was calibrated on that staff that La Condamine in Gradmessung 1736-40 in Ecuador had used. This enabled Liesganig to calculate the transition from the Viennese foot or fathom to the Toise du Pérou and the newly defined meter measure more precisely. The Liesganig's Toise from 1760 was calibrated on the original fathom measure of 1756 and resulted in the ratio of 100,000 Toisen = 102,764 Viennese fathoms. This measure then became the standard measure of all later Austrian measures of length until 1817 and for the cadastre of Austria-Hungary .

Due to Liesganig's special geodetic achievements, the Vienna observatory became the reference point for Austria-Hungary in terms of length, which was later transferred to the new observatory on the Türkenschanze.

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Individual evidence

  1. a b c d The Jesuit observatory. In: Maria G. Firneis, Hermann Haupt, Peter Holl: Observatories in Austria. On the Austrian Academy of Sciences: austriaca.at, 2005 ff.