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

Memmingen Memmingen (; Swabian: ''Memmenge'') is a town in 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 river that marks the Baden-W� ...

– 4 July 1562,

Leipzig Leipzig ( , ; Upper Saxon: ) is the most populous city in the German state of Saxony. Leipzig's population of 605,407 inhabitants (1.1 million in the larger urban zone) as of 2021 places the city as Germany's eighth most populous, as wel ...

) was a German

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

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, structure, space, models, and change. History On ...

Work

Hommel was appointed professor of mathematics at the

University of Leipzig Leipzig University (german: Universität Leipzig), 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 Decemb ...

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 ...

line system introduced by Hommel.

Tycho Brahe Tycho Brahe ( ; born Tyge Ottesen Brahe; generally called Tycho (14 December 154624 October 1601) was a Danish astronomer, known for his comprehensive astronomical observations, generally considered to be the most accurate of his time. He was ...

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 wor ...

Hommel is named after him.

Sources

* Johann Daniel Schulze, ''Abriß einer Geschichte der Leipziger Universität'', Hinrichs, 1810, p. 48. * Kevin Krisciunas (1999)
"Observatories"

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