Liesganig was born to Wolfgang, Hofmeister of Graz, and Rosalie. He went to study at the Jesuit College in Vienna from 1734 and was ordained in the
Society of Jesus in 1749. He taught mathematics from 1742 at the
University of Graz. In 1751 he received a doctorate from the Academy in Kosice and joined an expedition into the Tatra mountains. The next year, he became a professor at the University of Vienna, while also serving at the astronomical observatory of the Jesuit College at Vienna. He succeeded
Maximilian Hell in 1756 as director of the observatory. Liesganig took a keen interest on question of the exact shape of the earth, which was of great interest in the period and supported by Empress
Maria Theresa. In 1757, on the instance of
Ruđer Bošković, he had a zenith sector of 10 (Viennese) foot radius as well as a quadrant with two-and-half foot radius constructed by the mechanic Joseph Ramspoeck. He obtained a
Graham clock with a gridiron compensation pendulum. With this equipment in place, in 1758, he established the longitude of Vienna as 48°12′34.5″. After this he was involved in 1762 in measuring a base line near Neustadt (6238
toises long, 12158 metres) and another in Marchfield (6388 toises). An arc of about 3° was measured near Vienna. He used a star reference for some of his trigonometrical work, however he made an error because not all stations used the same star as a reference, leading to errors. In 1769 he proposed the measurement of another meridian arc in Hungary, writing to Empress
Maria Theresa for her support. An arc of 2° was measured between Kistelek and Csurog and he triangulated in the area to produce one of the early accurate maps of the region. Other collaborators included
Karl Scherffer (1716-1783),
Georg Ignaz von Metzburg (1735-1798) His Vienna triangulation was re-examined in 1806 and it was found to be in error only by about 7mm per kilometre. His book
Dimensio Graduum Meridiani Viennensis et Hungarici (1770) described his cartographic work. In 1772, parts of the Russian Empire went into Austria and Liesganig was ordered to map the new territory of
Galicia and
Lodomeria (Volyhnia). He was assisted by
Franz Xavier von Zach (1754–1832) and he moved his instruments from Vienna to the observatory at
Lviv where he then worked until his death. File:Liesganig quadrant.jpg|Liesganig's quadrant File:Zenith telescope.jpg|Zenith telescope Map Liesganig3.jpg|Triangulations File:Map Liesganig2.jpg|Map fragment File:Galizien_und_Lodomerien_Liesganig_Map_1824_copy.jpg|Map based on Liesganig's work Map_Liesganig1.jpg|Map fragment File:Galizien_und_Lodomerien.jpg|1780 map of Galizia and Lodomeria based on Liesganig's survey == References ==