Pieter Johannes van Rhijn

Pieter Johannes van Rhijn (March 24, 1886 – May 9, 1960) was a Dutch astronomer. Born in Gouda, he studied at Groningen. He served as director at the Sterrenkundig Laboratorium (Kapteyn Astronomical Institute) in Groningen and later served for many years as president of the International Astronomical Union (1932-1958).

He died in Groningen. The crater van Rhijn on the Moon is named after him, as is asteroid 2203 van Rhijn.