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Frederik Kaiser (1808-1872) and the
modernisation of Dutch astronomy
by Petra van der Heijden
Introduction
At the beginning of the 19th century, astronomy at the Dutch universities was
at a low ebb. The universities had no observing programme, and astronomical
instruments, if there, were mostly used for educational purposes.
Already in the 18th century the practice of astronomy had slowly shifted
towards the amateurs, who were mostly members of a learned society or had a
wealthy patron to provide them with the necessary tools.
In this tradition the young Frederik Kaiser was raised. Educated by his
uncle Johan Frederik Keyser (1766-1823), who was a proficient amateur
astronomer, Kaiser proved to be a real observational talent. This talent
brought him the first paid-for post of observer in the country. Famous for
his observations of Halley's comet, in 1837 he became director of
Leiden Observatory, and in 1845 a full professor. His broad approach of
astronomy was quite unique.
Science
Like many of his foreign contemporaries, Kaiser concentrated his research
on positional astronomy.
Measuring the positions and motions of stars and solar system bodies
(e.g. comets) with increasing precision was a major task for astronomy
in those days.
The meridian or transit circle was used to record the exact moment an
object crossed the meridian of the observatory. It originated from the
old mural quadrant or circle combined with a small transit telescope.
The altitude of the object could be read from the circle.
A wire micrometer was used to determine the angle between two objects.
Kaiser was the first to introduce this type of precision measurement in
Dutch astronomy. His observations soon rivalled with the best in the world.
Otto W. Struve (1819-1905), after having received Kaiser's measurements, in
1842 wrote:
``I am honestly grateful for your wonderful gift, and I
assure you I have
read it with the greatest interest (...) This interest increased when I became
convinced of the excellence of your micrometer measurements, which are so
fine that they leave the rest behind. I am pleased to see that, in order to
reach excellence, talent and industry are as important as, no even more
important than colossal dimensions of a telescope.''
Organisation
When he was still an observer, for many years Kaiser had worked in a poorly
equipped institute on top of the Leiden University academy building, knowing
that he would not get anywhere without new, state-of-the-art instruments. But
getting these meant struggling with authorities. From 1837 on, Kaiser always
dedicated a fairly large amount of his time to this problem.
In 1861 his efforts finally gained him a brand new, fully equipped observatory
building, the first of its kind in the Netherlands, along with a staff of
observers. This institute gave Dutch astronomy a prominent place on
the world map.
Popularisation
Kaiser's activities were not confined to professional astronomy only.
It was his aim to disclose the science of astronomy to the general
public. He considered it an essential element of a broad education, and
used it as a means to demonstrate the greatness and beauty of creation.
Kaiser became well known for his spellbinding lectures in popular astronomy
and his articles in popular magazines. His greatest achievement is probably
the writing of De Sterrenhemel (1844-1845), an overview of astronomical
theory and practice for the layman.
It appeared in four editions and was translated into German and Danish.
Naturally, Kaiser's fame was of great benefit in raising the funds for a new
observatory.
Goal
This project will search for a historical understanding of Kaiser's ideas
and actions in the context of their time. It will try to give answers to
questions such as: What/who were Kaiser's sources of inspiration? How
successful was Kaiser in reviving the science of astronomy in The
Netherlands, and how did he bring this about? What scientific goals
did he try to reach? How unique were his scientific methods, and how
were they received?
Given the fact that the effect of Kaiser's methods and ideas extend far
beyond his lifetime and discipline, we will follow his traces into 19th-
and 20th-century Dutch science (J.A.C. Oudemans, H.A. Lorentz, J. Bosscha,
J.D. van der Waals, H. Kamerlingh Onnes).
Method
For this project we will use published as well as unpublished sources.
Kaiser's articles and books will serve as a source for analysing
his activities in science and popularisation, whereas his correspondence
and his other papers (as kept in the archives of e.g. Leiden
Observatory and the Leiden University Library) are essential for tracing the
origin of his ideas.
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