Joseph Xaver Liesganig (13 February 1719 – 4 March 1799) was a Jesuit priest and geodesist who was a professor of mathematics at the

University of Vienna The University of Vienna (, ) is a public university, public research university in Vienna, Austria. Founded by Rudolf IV, Duke of Austria, Duke Rudolph IV in 1365, it is the oldest university in the German-speaking world and among the largest ...

. He taught mathematics from 1742 at the

University of Graz The University of Graz (, formerly: ''Karl-Franzens-Universität Graz'') is a public university, public research university located in Graz, Austria. It is the largest and oldest university in Styria, as well as the second-largest and second-old ...

. He was involved in measuring the extent of Austria, establishing the longitude of Vienna and in early trigonometrical mapping of the region. He was the last of the Jesuit astronomers at the Vienna observatory.

Life and work

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 The Society of Jesus (; abbreviation: S.J. or SJ), also known as the Jesuit Order or the Jesuits ( ; ), is a religious order of clerics regular of pontifical right for men in the Catholic Church headquartered in Rome. It was founded in 1540 ...

in 1749. He taught mathematics from 1742 at the

. 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 Maximilian Hell () (born Rudolf Maximilian Höll; May 15, 1720 – April 14, 1792) was an astronomer and an ordained Jesuit priest from the Kingdom of Hungary. The lunar crater Hell is named after him. Biography Born as Rudolf Maximilian Höl ...

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 Maria Theresa (Maria Theresia Walburga Amalia Christina; 13 May 1717 – 29 November 1780) was the ruler of the Habsburg monarchy from 1740 until her death in 1780, and the only woman to hold the position suo jure, in her own right. She was the ...

. In 1757, on the instance of

Ruđer Bošković Roger Joseph Boscovich (, ; ; ; 18 May 1711 – 13 February 1787) was a Croatian physicist, astronomer, mathematician, philosopher, diplomat, poet, theologian, Jesuit priest, and a polymath from the Republic of Ragusa.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

toise A toise (; symbol: T) is a unit of measure for length, area and volume originating in pre-revolutionary France. In North America, it was used in colonial French establishments in early New France, French Louisiana (''Louisiane''), Acadia (''Acad ...

s 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

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 Karl Scherffer (9 November 1716 – 24 July 1783) was an Austrian Jesuit mathematician and natural scientist. He contributed works in mathematics, optics and astronomy. He promoted the mathematical works of Leonhard Euler and the natural philosoph ...

(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 Lodomeria is the Latinized name of Volodymyr ( Old Slavic: , ; , ; ; ), a Ruthenian principality also referred to as the Principality of Volhynia, which was founded by the Rurik dynasty in 987 in the western parts of Kievan Rus'. It was centere ...

(Volyhnia). He was assisted by Franz Xavier von Zach (1754–1832) and he moved his instruments from Vienna to the observatory at

Lviv Lviv ( or ; ; ; see #Names and symbols, below for other names) is the largest city in western Ukraine, as well as the List of cities in Ukraine, fifth-largest city in Ukraine, with a population of It serves as the administrative centre of ...

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

External links

Dimensio graduum meridiani Viennensis et Hungarici
(1770) {{DEFAULTSORT:Liesganig, Joseph Xaver 1719 births 1799 deaths 18th-century Austrian astronomers