On 3 October 2026, Professor Harry van der Laan celebrates his 90th birthday. Leiden Observatory and ASTRON warmly congratulate him on this milestone and on a remarkable career that has had a lasting influence on Dutch and European astronomy.
Harry van der Laan joined the staff of Leiden Observatory in 1967, on the invitation of Jan Oort, at a crucial moment in the development of Dutch radio astronomy. The new Westerbork Synthesis Radio Telescope was approaching completion, and Harry played a major role in preparing for its scientific exploitation. In 1970 he became Professor of Radio Astronomy at Leiden University and subsequently served for many years in national and international scientific leadership roles.
He was a key person in the SRZM (Foundation for Radio Waves from the Sun and Milky Way, commonly known as the Netherlands Foundation for Radio Astronomy. The SRZM was responsible for operating the Kootwijk, Dwingeloo and Westerbork radio telescopes. During the transition from the modest Kootwijk and Dwingeloo facilities to the much larger and technically more demanding Westerbork telescope, Harry led the process that created a new organisational structure. This involved harnessing the scientific, technical and management activities of the observing facilities together with researchers and engineers in the Dutch universities, to create the national institute that evolved into the present-day ASTRON.
The 1970s were an exceptionally productive period for radio astronomy in the Netherlands. Under Harry’s leadership, and inspired by the vision of Jan Oort, Leiden, the other Dutch universities and Westerbork attracted an energetic international community of young astronomers, engineers and students. Many of them went on to play leading roles in astronomy throughout the world.
Harry also took the initiative in establishing the UK–Netherlands collaboration at the observatories on La Palma, strengthening the participation of Dutch astronomers in major optical facilities and European astronomical cooperation.
Harry’s influence extended far beyond the Netherlands. Earlier in his career he had studied in Cambridge with Martin Ryle and had been involved in the beginnings of the Young European Radio Astronomers Conference, YERAC. He later became an important figure in European astronomy and, from 1988 to 1992, served as Director General of the European Southern Observatory (ESO). His period at ESO coincided with the formative years of the Very Large Telescope, and he had already played an important role in the planning and site-selection process that led to the construction of the VLT at Paranal in Chile.
Throughout his career, Harry combined scientific insight with a strong commitment to building institutions and opportunities for future generations. His contributions helped connect the pioneering era of Dutch radio astronomy, beginning with Kootwijk, Dwingeloo and Westerbork, with the modern era of multispectral astronomy, represented by organisations such as ASTRON and ESO.
On the occasion of his 90th birthday, we celebrate not only an outstanding astronomer, but also a builder of organisations, a mentor of young scientists and a major figure in the development of Dutch, European and international astronomy.
Happy 90th birthday, Harry!
Harry, van harte gefeliciteerd met je 90ste verjaardag!