He spent most of his career at Leiden University, retiring in 1984. He published widely in astronomy, and dealt with the solar corona, and interstellar clouds. After 1960 he was a leader in international space research projects.[6]
^van der Kruit, Pieter C. (2019). "Appendix A.4: Oort and His Students: a List of Ph.D. Theses". Jan Hendrik Oort. Astrophysics and Space Science Library. Vol. 459. Springer International Publishing. pp. 633–635. doi:10.1007/978-3-030-17801-7. ISBN978-3-030-17800-0. S2CID199240526.