Hendrik van de Hulst

Hendrik Christoffel van de Hulst (November 19 1918 – July 31 2000) was a Dutch astronomer.

In 1944, while still a student, he predicted the existence of the 21 cm hyperfine line of neutral interstellar hydrogen. After this was discovered, he participated 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.

He won the Henry Draper Medal in 1955 and the Bruce Medal in 1978.