Michael van Langren

== Contributions ==

== Contributions ==

Among his contributions were attempts to determine [[longitude]].{{cite web |url=http://anewdomain.net/pi-guy-2-mysterious-code-is-the-key-to-the-longitude-problem/ |title=On Michael Van Langren, The Moon and The Longitude Problem |year=2017}}

Determining longitude at sea was one of the major scientific problems of the seventeenth century, and Van Langren devoted much of his work to finding a practical solution. As early as 1621 he proposed that longitude could be calculated by observing the [[Moon]], particularly by tracking how the illumination of lunar mountains and craters changed during the lunar cycle.{{cite web |title=Langren, Michael Florent van |url=https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/langren-michael-florent-van |website=Encyclopedia.com}}

[[Image:Grados de la Longitud.jpg|thumb|400px|[[Graphics|A graph]] of statistical data, showing the wide range of estimates of the distance in longitude between [[Toledo, Spain|Toledo]] and [[Rome]].|left]]

To show the magnitude of the problem, he created the first (known) [[graphics|graph]] of statistical data, showing the wide range of estimates of the distance in longitude between [[Toledo, Spain|Toledo]] and [[Rome]].{{cite journal |last1=Friendly |first1=Michael |last2=Valero-Mora |first2=Pedro |last3=Ibáñez Ulargui |first3=Joaquín |year=2010 |title=The First (Known) Statistical Graph: Michael Florent van Langren and the Secret of Longitude |journal=The American Statistician |volume=64 |pages=185–191}}

He believed he could improve the accuracy of longitude determination, particularly at sea, by observing peaks and craters of the [[Moon]] as they appear and disappear, not only during eclipses of the Moon but also in the course of the entire lunation.{{cite book |last=van der Krogt |first=Peter |url=http://www.gencat.cat/llengua/BTPL/ICOS2011/190.pdf |title=Els noms en la vida quotidiana. Actes del XXIV Congrés Internacional d'ICOS sobre Ciències Onomàstiques |year=2011 |pages=1851–1868 |chapter=Michiel Florent van Langren and Lunar Naming}}

His proposed method required accurate observations and detailed mapping of the lunar surface, which led him to undertake systematic studies of the Moon.

[[Image:Langrenus map of the Moon 1645.jpg|thumb|right|200px|[[Michael Van Langren|Langren's]] map (1645)]]

[[Image:Langrenus map of the Moon 1645.jpg|thumb|right|200px|[[Michael Van Langren|Langren's]] map (1645)]]

Among his contributions were attempts to determine [[longitude]].{{cite web | url=http://anewdomain.net/pi-guy-2-mysterious-code-is-the-key-to-the-longitude-problem/ | title=On Michael Van Langren, The Moon and The Longitude Problem | year=2017}} To show the magnitude of the problem, he created the first (known) [[graphics|graph]] of statistical data, showing the wide range of estimates of the distance in longitude between [[Toledo, Spain|Toledo]] and [[Rome]]. He believed he could improve the accuracy of longitude determination, particularly at sea, by observing peaks and craters of the [[Moon]] as they appear and disappear, not only during eclipses of the Moon but also in the course of the entire lunation. This led him to make a map of the Moon (published in 1645), and he planned to produce maps of the Moon at thirty different [[Lunar phase|phase]]s, but never realized this plan. He was the first to assign names to various lunar features, but few of these names were widely accepted because they mostly corresponded to [[Catholic Church|Catholic]] monarchs, scientists, and artists.{{Cite book|url=http://www.gencat.cat/llengua/BTPL/ICOS2011/190.pdf|title=Els noms en la vida quotidiana. Actes del XXIV Congrés Internacional d'ICOS sobre Ciències Onomàstiques.|last=van der Krogt|first=Peter|year=2011|pages=1851–1868|chapter=Michiel Florent van Langren and Lunar Naming}}

This led him to make a map of the Moon (published in 1645), and he planned to produce maps of the Moon at thirty different [[Lunar phase|phases]], but never realized this plan. He was the first to assign names to various lunar features, but few of these names were widely accepted because they mostly corresponded to [[Catholic Church|Catholic]] monarchs, scientists, and artists.

[[Image:Grados de la Longitud.jpg|thumb|center|400px|[[Graphics|A graph]] of statistical data, showing the wide range of estimates of the distance in longitude between [[Toledo, Spain|Toledo]] and [[Rome]].]]

Van Langren actively promoted his ideas to the Spanish court. In 1625 he presented his longitude method at [[Dunkirk]] to the Archduchess [[Isabella Clara Eugenia]], and in the following years he travelled to [[Spain]] seeking royal support for his work. During this period he produced astronomical and hydrographical tables intended to support his longitude calculations, although these works have not survived. In [[Madrid]] he also published ''Advertencias de Miguel Florencio Van Langren a todos los professores y amadores de la mathemática'' (c.1634), outlining his approach to the longitude problem.

He also published his observations of the [[comet]] of 1652, [[C/1652 Y1]]. He made various maps of the [[Southern Netherlands|Spanish Netherlands]]. He also produced plans for a port near [[Dunkirk]], improvements to the port of [[Ostend]], efforts to clear the canals of [[Antwerp]], flood control concepts, and fortifications.

He also published his observations of the [[comet]] of 1652, [[C/1652 Y1]]. He made various maps of the [[Southern Netherlands|Spanish Netherlands]]. He also produced plans for a port near [[Dunkirk]], improvements to the port of [[Ostend]], efforts to clear the canals of [[Antwerp]], flood control concepts, and fortifications.{{cite journal |last=Keuning |first=Johannes |year=1956 |title=The Van Langren Family |journal=Imago Mundi |volume=13 |pages=101–109}}

He named crater [[Langrenus (crater)|Langrenus]] on the [[Moon]] after himself, and the name has been preserved to this day.

He named crater [[Langrenus (crater)|Langrenus]] on the [[Moon]] after himself, and the name has been preserved to this day.

==External links==

==External links==

* [http://galileo.rice.edu/Catalog/NewFiles/langren.html The Galileo Project: Langren, Michael Florent van]

* [http://galileo.rice.edu/Catalog/NewFiles/langren.html The Galileo Project: Langren, Michael Florent van]