Jan Hendrik Oort was a world-renowned astronomer at the Leiden Observatory. In the last century, he mapped the structure of the Milky Way: a core with spiral arms. He was the pioneer of radio astronomy in the Netherlands, the branch of astronomy that studies radio waves from space to investigate, among other things, stars and planets that are not visible with optical telescopes. He was one of the founders of the European Southern Observatory (ESO) in Chile. And he brought fame to Leiden, the university and the Netherlands. He was a shining example for me when I met him, as a budding amateur astronomer, at the Observatory in 1980. A star in the university's sky!
