10.4 De Sitter and Leiden
217
10.4 De Sitter and Leiden
Kapteyn’s institute had a minimal staff. The permanent support staff consisted
of Teunis Willem de Vries, who was first described as a ‘clerk’ and later as
‘amanuensis’ (laboratory assistant), and next to him since 1901 one scientific
assistant, which initially was Willem de Sitter. There would have been personnel
from the university to provide for cleaning and maintenance of the laboratory,
but support in education and research could only be financed from temporary
funding.
De Sitter, who was born in 1872, would normally have to wait for a professorship until 1921 (he would then be 49 years of age), the year in which Kapteyn
would retire. The chances of a second professor of astronomy in Groningen
were in fact zero. De Sitter’s contributions were considerable, according to the
articles in the series Publications of the Astronomical Laboratory at Groningen.
Some concerned research fitting in with Kapteyn’s large program, but some
concerned the field of his own PhD thesis research, namely the properties of
the orbits and masses of Jupiter’s four large satellites. He certainly qualified for
a position where he could set up his own line of research. But the only two
other Dutch professorships in the Netherlands were in Leiden, which was held
by Hendricus van de Sande Bakhuyzen and in Utrecht by Albertus Antonie
Nijland (see Fig. 10.8).
Nijland had studied in Utrecht and had defended a PhD thesis there twice,
first in 1896 with Willem Kapteyn on a pure mathematics subject and in 1897
with Jean Oudemans on measurements, partly photographic, of a star cluster.
Jean Oudemans was to retire at the end of the academic year 1897–98 and a
vacant position would result. It is not unlikely that Nijland quickly wrote his
second dissertation, now in astronomy, in view of the upcoming vacancy. Not
surprisingly, the professorship in Utrecht and the directorate of the observatory
were first offered to Kapteyn. Kapteyn did not accept. At that time the Cape
Photographic Durchmusterung was nearing completion and Kapteyn was busy
trying to find a solution for the problem of the distribution of the stars in space
by means of proper motions. In 1896 he had opened his own Astronomical
Laboratory in Groningen, although still in temporary housing, and perhaps
he no longer had any special ties with Utrecht, where he had after all he had
studied at the university. Anyway, he turned down the offer. Utrecht then
indeed appointed Albertus Nijland to the position.
Of course, the vacancy in Utrecht came far too early for Willem de Sitter.
But in 1908 Hendricus van de Sande Bakhuyzen retired. This position, too,
was first offered to Kapteyn. The letter from the Leiden Faculty, in which this
offer was made, has been preserved in the Archives of the Sterrewacht; it was
217
10.4 De Sitter and Leiden
Kapteyn’s institute had a minimal staff. The permanent support staff consisted
of Teunis Willem de Vries, who was first described as a ‘clerk’ and later as
‘amanuensis’ (laboratory assistant), and next to him since 1901 one scientific
assistant, which initially was Willem de Sitter. There would have been personnel
from the university to provide for cleaning and maintenance of the laboratory,
but support in education and research could only be financed from temporary
funding.
De Sitter, who was born in 1872, would normally have to wait for a professorship until 1921 (he would then be 49 years of age), the year in which Kapteyn
would retire. The chances of a second professor of astronomy in Groningen
were in fact zero. De Sitter’s contributions were considerable, according to the
articles in the series Publications of the Astronomical Laboratory at Groningen.
Some concerned research fitting in with Kapteyn’s large program, but some
concerned the field of his own PhD thesis research, namely the properties of
the orbits and masses of Jupiter’s four large satellites. He certainly qualified for
a position where he could set up his own line of research. But the only two
other Dutch professorships in the Netherlands were in Leiden, which was held
by Hendricus van de Sande Bakhuyzen and in Utrecht by Albertus Antonie
Nijland (see Fig. 10.8).
Nijland had studied in Utrecht and had defended a PhD thesis there twice,
first in 1896 with Willem Kapteyn on a pure mathematics subject and in 1897
with Jean Oudemans on measurements, partly photographic, of a star cluster.
Jean Oudemans was to retire at the end of the academic year 1897–98 and a
vacant position would result. It is not unlikely that Nijland quickly wrote his
second dissertation, now in astronomy, in view of the upcoming vacancy. Not
surprisingly, the professorship in Utrecht and the directorate of the observatory
were first offered to Kapteyn. Kapteyn did not accept. At that time the Cape
Photographic Durchmusterung was nearing completion and Kapteyn was busy
trying to find a solution for the problem of the distribution of the stars in space
by means of proper motions. In 1896 he had opened his own Astronomical
Laboratory in Groningen, although still in temporary housing, and perhaps
he no longer had any special ties with Utrecht, where he had after all he had
studied at the university. Anyway, he turned down the offer. Utrecht then
indeed appointed Albertus Nijland to the position.
Of course, the vacancy in Utrecht came far too early for Willem de Sitter.
But in 1908 Hendricus van de Sande Bakhuyzen retired. This position, too,
was first offered to Kapteyn. The letter from the Leiden Faculty, in which this
offer was made, has been preserved in the Archives of the Sterrewacht; it was