12 February
1893: On 12 February 1893, Marcel Gilles Jozef Minnaert was born.
Minnaert was a Belgian astronomer and solar physicist who pioneered in solar spectrophotometry and showed how such a technique could reveal much about the structure of the Sun's outer layers.
Originally, he studied biology at the University of Ghent in his native Belgium and physics at the University of Leiden in the Netherlands. After World War I he joined the solar physics group at the University of Utrecht in the Netherlands.
From 1937 to 1963 he was director of the Utrecht Observatory. He and his students led in the development of detailed quantitative analysis of the solar spectrum. Their development of the curve of growth method made it possible for astronomers to obtain precise information about stellar atmospheres. He investigated light scattering from the surface of the moon and participated in the naming of many lunar features.
Imprisoned during World War II, he taught astronomy and physics to his fellow prisoners. After the war he was active in international organisations. A revered teacher, Minnaert published a collection of poems related to astronomy and popular books, as well as textbooks. He died on 26 October 1970.
