Johann Hommel (also ''Johannes Homelius'', ''Hummelius'', ''Homilius'', ''Hummel''; 2 February 1518 in

Memmingen Memmingen (; Swabian German, Swabian: ''Memmenge'') is a town in Swabia (Bavaria), Swabia, Bavaria, Germany. It is the economic, educational and administrative centre of the Danube-Iller region. To the west the town is flanked by the Iller, the ...

– 4 July 1562 in

Leipzig Leipzig (, ; ; Upper Saxon: ; ) is the most populous city in the States of Germany, German state of Saxony. The city has a population of 628,718 inhabitants as of 2023. It is the List of cities in Germany by population, eighth-largest city in Ge ...

) was a German

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

and

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

Work

Hommel was appointed professor of mathematics at the

University of Leipzig Leipzig University (), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December 1409 by Frederick I, Electo ...

in 1551. In 1552 or 1553, Richard Cantzlar introduced transversal dot lines in graduations. It was a variant of the

zigzag A zigzag is a pattern made up of small corners at variable angles, though constant within the zigzag, tracing a path between two parallel lines; it can be described as both jagged and fairly regular. In geometry, this pattern is described as a ...

line system introduced by Hommel.

Tycho Brahe Tycho Brahe ( ; ; born Tyge Ottesen Brahe, ; 14 December 154624 October 1601), generally called Tycho for short, was a Danish astronomer of the Renaissance, known for his comprehensive and unprecedentedly accurate astronomical observations. He ...

obtained the zigzag line system from Hommel. The

lunar crater Lunar craters are impact craters on Earth's Moon. The Moon's surface has many craters, all of which were formed by impacts. The International Astronomical Union currently recognizes 9,137 craters, of which 1,675 have been dated. History The wo ...

Hommel is named after him.

Sources

* Johann Daniel Schulze, ''Abriß einer Geschichte der Leipziger Universität'', Hinrichs, 1810, p. 48. * Kevin Krisciunas (1999)
"Observatories"
* Torsten Woitkowitz: Der Landvermesser, Kartograph, Astronom und Mechaniker Johannes Humelius (1518–1562) und die Leipziger Universität um die Mitte des 16. Jahrhunderts, in: Sudhoffs Archiv 92 (2008), S. 65–97. * Marion Gindhart and Alexander Hubert: Art. „Mathematische Wissenschaften (CamLex)“, in: Opera Camerarii Online, http://wiki.camerarius.de/Mathematische_Wissenschaften_(CamLex), section „Camerarius und Johann Hommel“.

External links

* 16th-century German astronomers 16th-century German mathematicians 1518 births 1562 deaths 16th-century German writers 16th-century German male writers {{Germany-astronomer-stub