Kees de Jager

Cornelis "Kees" de Jager (pronounced [ˈkeːz də ˈjaːɣər]; 29 April 1921 – 27 May 2021) was a Dutch astronomer who specialized in predicting solar variation to assess the Sun's impact on future climate. He was the General Secretary of the IAU from 1967 to 1973 and former director of the observatory at Utrecht. He was a fellow with the Committee for Skeptical Inquiry and played an important role in the European skeptical movement as the first chairman of both Stichting Skepsis and the European Council of Skeptical Organisations.