Career
He worked at the Dutch Bosscha Observatory in Indonesia between 1928 and 1935, and became assistant professor at Uppsala"s Kvistabergs Observatorium (Kvistaberg Observatory) in 1948. He worked originally on double stars but it was the open star clusters and their properties that became his main area of research. From the 1950s onwards, he was the leading writer of popular astronomy in Sweden among the professional astronomers.
His books inspired generations of young people to become interested in astronomy.
Asteroid 2114 Wallenquist was named in his honour.