Johann Wempe was born on New Year's Eve 1906 in Bremen
and originally wanted to become a school teacher.
Bremen was a place for ships to go to sea which
in those days needed astronomical knowledge for navigation.
This apparently did the trick to attract Wempe to astronomy.
In fact during his initial school years he participated in
evening classes of the extramural studies, and also used the
old instrument of the famous Bremen doctor and astronomer
After 7 years studies of math, physics and astronomy in Goettingen,
Wempe received his PhD from Goettingen in 1932 with a dissertation
on the "contributions to photographic spectral photometry" working
for Prof Kienle. In 1936, he became scientific assistant at Landessternwarte
Heidelberg. Here he worked on eclipsing binaries (!)
and asteroids (Kleinplaneten) one of which is named after him!
Because of the political climate in Heidelberg, Wempe decided
in 1938 to move to Jena to join H. Siedentopf. He was fragile and
not so healthy, so he did not have to go to the front (during WWII).
Instead he could work on the "wavelength dependence of atmospheric
extinction", the topic of his Habilitation thesis in 1944 in Jena
(published in Astr. Nachrichten 275, 1, 1947).
That same year 1944 he moved on to Potsdam working with his former
PhD advisor Kienle who had become director of the Astrophysical
Observatory Potsdam at its Telegraphenberg site. Their joint goal
was a quick rebuilding of that Observatory (mainly repairing the
instruments that got damaged in the war). He was appointed
"Observer" in 1946, and "Lecturer" in 1947. Wempe in those days
also was the head of the workers' union, perhaps the first sign
of what became his will (his testament says that the money he left
should be used to "improve the living conditions of the people
in the observatory"). Wempe was never married. His sister helped
him to get by. All his life he liked gardening (esp. sun-flowers)
and music (member of the Händel society). He was a very modest man.
After the war had ended, he became a professor at Humboldt Univ.
in Berlin in 1948, and in 1958 he got the chair which he held
till his retirement in 1971. For 22 years, he was the editor
of the journal Astronomische
Nachrichten; after his retirement
he became interested in the history of astronomy in Potsdam.
He is said to have been a very critical and demanding teacher
as well as editor. He was also known to have had a good sense
of humour, despite his natural nordic reserve to people.
Two years after Prof. Grotrian's death (1954), he became director
of the Astrophysical Observatory Potsdam (AOP); he also was a part-time
director of the Babelsberg Sternwarte then. He likened his position
to that of a "conductor of an orchestra" (quoting his own words).
Under his directorship, the AOP was united with the Sonneberg Obs.
to become the "institute for stellar physics" in 1967. Not much
later, in 1969, the Zentralinstitut for Astrophysics was founded
and Wempe became director of one of the scientific branches.
It is interesting to remember that Wempe played a key role in
the concept and realization of the Tautenburg 2m Schmidt mirror,
which was installed in 1960. Wempe developed the idea and use
of the objective prism; so, not only did he know classical
astronomy (celestial mechanics etc), but also spectroscopy.
Scientifically, he is probably most reknowned for his work
on the "absolute calibration of the intensity distribution
of an AO star", which was published in 1940 (Kienle et al.).
After he became director, he did not publish much anymore.
Still he always worked late hours and cared a lot about the
well-being of the employees of the observatory. He also saw
to it that there would be an AOP Christmas party every year.
In all his years as director, his major goal has been the
the modernisation of the instrumental equipment of the AOP,
to provide the younger astronomers with the best possible
working conditions in astrophysics. (A good legacy indeed!)
Johann Wempe died on May 29, 1980 at the age of 73.
(compiled/translated from various obituaries by hz)