Hendrik Christoffel "Henk" van de Hulst ForMemRS (Utrecht, November 19, 1918 – Leiden, July 31, 2000) was a Dutch astronomer and mathematician.
In 1944, while a student in Utrecht, he predicted the existence of the 21 cm hyperfine line of neutral interstellar hydrogen. After this line was discovered, he participated, with Jan Oort and Alex Muller, in the effort to use radio astronomy to map out the neutral hydrogen in our galaxy, which first revealed its spiral structure.
He spent most of his career at the University of Leiden, 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.
- Henry Draper Medal of the National Academy of Sciences (1955)
- Eddington Medal of the Royal Astronomical Society (1955)
- Bruce Medal of the Astronomical Society of the Pacific (1978)
- Karl Schwarzschild Medal of the Astronomische Gesellschaft (1995)
The asteroid (2413) van de Hulst
is named for him, and the asteroid (2412) Wil is named for his wife Wilhelmina.
Henk van de Hulst was named an Honorary Member of the Royal Astronomical Society of Canada on 1968-05-17.