The Oort was a Dutch coin from the 15th century, but it was also, more famously, a Dutch astronomer. Jan Hendrik Oort was an astronomer from 1900. The Frisian astronomer was brought to Leiden by colleague Willem de Sitter in 1924. Oort stayed in Leiden for the rest of his long life, and is still considered one of the pioneers of radio astronomy. After his death in 1992, physicist Chandrasekhar stated: "The great oak of Astronomy has been felled; and we are lost without its shadow"