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Top 10 Unknown Facts about Frederik Kaiser

Known chiefly for his reorganization of the Leiden observatory and his work on the fundamental coordination of stars, Frederik Kaiser was a Dutch astronomer who served as a director of the Leiden Observatory for 34 years.

Frederik Kaiser was born on 10 June 1808 in Amsterdam, and his parents were Johann Wilhelm Keyser and Anna Sibella Liernur. His father died when he was eight years old and as a result, he was raised and educated by his uncle Johan Frederik Keyser. 

Although Kaiser was given the name Friedrich at birth, he preferred the Dutch form, Frederik. Here are the top 10 unknown facts about him.

1. He was Raised by his Uncle

Kaiser was the oldest boy of eight children born to Johann Wilhelm Keyser and Anna Sibella Liernur. His parents were immigrants from Nassau鈥怐ietz in Germany. Kaiser’s father, a teacher of German, died in 1817 when Frederik was 8 years old.

Kaiser was then raised by his uncle, Johan Frederik Keyser, a municipal employee and teacher of mathematics in Amsterdam. Keyser was a member of several learned societies and was known as a proficient amateur astronomer.

It is his uncle who discovered his talent in mathematics and observatory astronomy and he decided to teach him the trade.

2. He was the Director of the Leiden Observatory

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In 1826 Kaiser became an observer at the Leiden observatory, but the instruments were inferior and his relationship with the director Uylenbroek was tense. He left the observatory in 1831.

He became a lecturer in astronomy and director of the observatory in 1837. His contributions as a director included the foundation of a completely new observatory building in Leiden.

Kaiser also oversaw the introduction of statistics and precision measurements in daily astronomical practice. Moreover, he was a gifted teacher and a skillful populariser of astronomy.

3. He Calculated the Length of Martian Day

 In 1862, Kaiser began observing Mars with the observatory telescope. In 1862 and 1864, Mars was especially close to the earth, which means the surface features on Mars were clearer than unusual.

Kaiser used the opportunity to study the red planet, and he compared his drawings with those of Robert Hooke and Christian Huygens two centuries earlier. He was able to calculate the exact length of a Martian day: 24 hours, 37 minutes, 22.6 seconds.

So esteemed was Kaiser as an observer that when Robert Proctor in 1867 named all the features on Mars after astronomers, he called the most prominent feature the “Kaiser Sea.”

4. He built a new Leiden Observatory

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Kaiser鈥檚 public persona was of considerable benefit in raising the funds for a new observatory. He had long planned a new, up-to-date building, based on models from Germany and the Pulkovo Observatory (Saint Petersburg, Russia).

The Dutch government, however, was not eager to support his initiative. After many years of fruitless lobbying, a national fundraising campaign for Kaiser鈥檚 observatory was inaugurated.

A fully equipped observatory building was finished in 1860, the first of its kind in the Netherlands. Instruments included a state-of-the-art meridian circle by Pistor and Martins and a 7-in. Merz refractor. The staff was enlarged with an extra observer and some calculators.

 5. He Graduated with a Bachelor’s in Mathematics and Physics

From age eight to fourteen Kaiser was educated by his uncle; by then he had already published a computation of the occultation of the Pleiades by the moon.

He later studied at Leiden University, from which he earned a bachelor’s in mathematics and physics in 1831. His doctoral advisors were Pieter Johannes Uylenbroek and Gerard Moll.

Kaiser owed much of his University education to his uncle鈥檚 colleague, who supported him after the Dutch government failed to provide him with a scholarship.

6. He Initiated an Extensive Observational Program

Kaiser then initiated an extensive observational program. From 1864 to 1868, the fundamental parameters of some 180 stars were measured, followed by 202 stars for the Europaische  Gradmessung (European Geodetic Survey).

The results were published in 1868. Further work at the observatory was done on micrometer measurements of binary stars and planetary diameters, comets, and the rotation period of Mars.

 Between 1870 and 1876, the observatory participated in the observation of zones for the star catalog of the Astronomische Gesellschaft.

7. He has Inspired Many Astronomers

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After Kaiser鈥檚 departure, many scientists of the next generation were inspired by his lectures. Among his students were Van de Sande Bakhuyzen, Martin Hoek, and Jean Abraham Chretien Oudemans, who completed their doctoral research at Leiden Observatory.

Also inspired by Kaiser鈥檚 teachings were Hendrik Lorentz, Johannes Bosscha (later director of the Delft Polytechnical Institute), and chemist Johannes Diderik van der Waals.

Kaiser initiated the dissemination of a new level of precision in Dutch science. Craters on the Moon and Mars are named for Kaiser. His papers may be found at the Leiden Observatory and Leiden University Library.

8. He was a Member of Various Astronomical Organizations

Kaiser had occupied astronomy-related functions as supervisor of the geodetic survey of the Dutch East Indies From 1844 to1857. In 1867 he became the Dutch delegate and board member in the Europaische Gradmessung.  

He was also a member of the Royal Dutch Academy of Sciences, the Holland Society of Sciences, the Royal Astronomical Society, the Prussian Academy of Science, and the Astronomische Gesellschaft.

9. He inspected Dutch Royal Navy Instruments

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Kaiser devoted special attention to the theory of the equatorially mounted telescope, to time determination, and to a critical investigation of Airy鈥檚 double-image micrometer.

He advised the government on nautical instruments, becoming an inspector of instruments for the navy,

Kaiser also invented the fluid compass and improved Steinheil鈥檚 prismatic circle, which was more precise than the sextant.

10. He Authored Several Astronomical Books

Frederik Kaiser is credited with the advancement of Dutch astronomy through his scientific contributions to positional measurements, and his popularization of astronomy in the Netherlands.

He also contributed in an important way to the diffusion of astronomical knowledge in the Netherlands through his popular book De Sterrenhemel, which had several editions; by his popular account of planet discoveries (1851); and his Populair Sterrekundig Jaarboek.