Editing Frederik Kaiser (section)

{{short description|Dutch astronomer}}
{{about|the astronomer|the athlete|Frederick Kaiser}}
[[Image:Frederik Kaiser.jpg|thumb|Frederik Kaiser, unknown date.]]
[[File:Frederik-Kaiser-4.jpg|thumb|Johan Heinrich Neuman: Frederik Kaiser, 1872. Collection Leiden University.]]

'''Frederik Kaiser''' ([[Amsterdam]], 10 June 1808 &ndash; [[Leiden]], 28 July 1872) was a Dutch [[astronomer]].<ref>Rob van den Berg, ''Een passie voor precisie. Frederik Kaiser (1808-1872). Vader van de Leidse Sterrewacht''. Amsterdam: Prometheus, 2022. 384 pages (in Dutch).</ref>
He was director of the [[Leiden Observatory]] from 1838 until his death.

He is credited with the advancement of Dutch astronomy through his scientific contributions of positional measurements, his popularization of astronomy in the [[Netherlands]], and by helping to build a state-of-the-art [[observatory]] in 1861. Today it is known as the "Old Observatory").
Among his students were [[Jean Abraham Chrétien Oudemans]], [[Johannes van der Waals]], [[H. G. van de Sande Bakhuyzen|Hendricus Gerardus van de Sande Bakhuyzen]] and [[Hendrik Antoon Lorentz]]. 

Kaiser made a series of drawings of [[Mars]] at its opposition in 1862 and made a fairly precise determination of its [[rotational period]] by comparing his drawings with those of [[Christiaan Huygens]].

[[Impact crater|Craters]] on [[Kaiser (Martian crater)|Mars]]<ref>{{cite book
 | first1=Marvin | last1=Bolt
 | first2=Thomas | last2=Hockey
 | first3=JoAnn | last3=Palmeri
 | title=Biographical Encyclopedia of Astronomers
 | editor1-first=Virginia | editor1-last=Trimble
 | editor2-first=Thomas R. | editor2-last=Williams
 | editor3-first=Katherine | editor3-last=Bracher
 | editor4-first=Richard | editor4-last=Jarrell
 | editor5-first=Jordan D. | editor5-last=Marché
 | editor6-first=F. Jamil | editor6-last=Ragep
 | year=2007 | isbn=978-0387304007
 | publisher=Springer Science & Business Media
 | url=https://books.google.com/books?id=t-BF1CHkc50C }}</ref> and on the [[Kaiser (lunar crater)|Moon]] are named in his honour, as well as [[asteroid]] [[1694 Kaiser]].

In [[Richard Proctor]]'s now-abandoned Martian nomenclature, [[Syrtis Major Planum]] was called the "Kaiser Sea".  This nomenclature was later dropped in favor of the one introduced by [[Giovanni Schiaparelli]].

Kaiser's parents were Johann Wilhelm Keyser and Anna Sibella Liernur but he was raised by his uncle Johan Frederik Keyser from the age of eight.<ref>{{cite book |title=The Biographical Encyclopedia of Astronomers |last=Hockey |first=Thomas |year=2009 |publisher=[[Springer Publishing]] |isbn=978-0-387-31022-0 |accessdate=August 22, 2012 |url=http://www.springerreference.com/docs/html/chapterdbid/58738.html}}</ref>

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Grave of Frederik Kaiser on the Groenesteeg graveyard in Leiden, the Netherlands 03.jpg|Grave of Frederik Kaiser on the [[w:nl:Begraafplaats Groenesteeg|Groenesteeg graveyard]] in Leiden, the Netherlands. Grave number 400, 2021.
Leiden old observatory2.jpg|The Old Observatory in Leiden, 2006.
Leiden-Sterrewacht-2013-a.jpg|The Old Observatory after restoration, 2013.
</gallery>