John Seiradakis (Greek: Ιωάννης-Χιου Σειραδάκης; 5 March 1948 – 3 May 2020) was a Greek astronomer and professor emeritus at the Department of Physics of the Aristotle University of Thessaloniki. He is best known for his contributions in the understanding of radio pulsars, the Galactic Center and archaeoastronomy. Since the early 2000s he was heavily involved in the decoding of the Antikythera mechanism. He was a founding member of the Hellenic Astronomical Society, the European Astronomical Society and the International Olympiad on Astronomy and Astrophysics (IOAA).
Personal life
John Seiradakis was born in Chania, Crete, Greece, on 5 March 1948 to Mercy Burdett Money-Coutts Seiradaki and Michael Seiradakis. His mother was a British archaeologist. He had a younger sister, Sophia Hester Seiradaki. He completed his primary education, as well as two years of high school in Chania. In 1966 his family moved to Athens so he finished the last four grades of high school in Vyronas. He was admitted to the National and Kapodistrian University of Athens, from which he received his Degree in Physics in 1971 (Class of 1970). He continued his post-graduate studies at the Victoria University of Manchester, from which he received his M.Sc. (1973) and his Ph.D. (1975) in Radio Astronomy.
He had two children, Elena, currently an associate professor of biochemistry at Oxford University, and Michael, currently a medical doctor working in Germany.
He died on 3 May 2020 in his house in Thessaloniki, due to complications from cancer. An obituary appeared in Nature Astronomy. On June 7, 2021, the Governing Council of the Hellenic Astronomical Society decided to honour his memory by naming one of the plenary lectures of the biannual conference of the Society to "John H. Seiradakis Plenary Lecture".
Career
John Seiradakis conducted his M.Sc. and Ph.D. projects under the supervision of Dr. John G. Davies. His M.Sc. thesis was entitled "High sensitivity pulsar search." His MSc thesis examiners were Dr. Bryan Anderson and Prof. Antony Hewish. For his Ph.D. project, entitled "Low latitude pulsar survey at 408 MHz", he designed and conducted a sensitive survey for pulsars in the galactic plane. This survey discovered 18 new radio pulsars, more than 20% of the then known population. His PhD viva examiners were Dr. Robin G. Conway and Prof. Bernard E.J. Pagel. After receiving his Ph.D., Seiradakis moved to Germany as a postdoctoral fellow at the Max Planck Institute for Radio Astronomy (MPIfR), working under Prof. Richard Wielebinski. At the MPIfR, he made contributions to the understanding of pulsar emission and helped in the development of the first-generation pulsar instrumentation for the 100-m Effelsberg Radio telescope. He returned to the MPIfR several times during his career; in 1979 as a postdoctoral researcher, from 1982 to 1984 as an Alexander von Humboldt fellow and in 1991 as a visiting researcher on sabbatical leave from the University of Thessaloniki.
In 1978 he became a researcher at the University of Hamburg. Together with Dr. W. Huchtmeier and others, he performed a comprehensive survey of the neutral hydrogen distribution in nearby galaxies using the 100-m radio telescope at Effelsberg.
From 1982 to 1984 he worked as a researcher at the University of California, San Diego, where he continued his research on pulsar emission and interstellar scintillation.
In 1984, together with collaborators A. N. Lasenby, F. Yusef-Zadeh, R. Wielebinski and U. Klein, Seiradakis performed some of the first polarimetric observations of Sag A* at 10 GHz. This study revealed an extended polarised radio source with jet-like lobes originating from the Galactic Center.
In 1986 he joined the Department of Physics of the Aristotle University of Thessaloniki and in 1996 was promoted to Professor. As a faculty member, he contributed in numerous fields, including neutron stars (pulsars), neutral hydrogen modelling in nearby galaxies, the Galactic Center, Flare Stars, Lunar Transient Phenomena and Archaeoastronomy. He published more than 74 scientific papers in refereed journals, and more than 80 papers in conference proceedings and special volumes, as well as three University-level textbooks. He was a founding member of the Hellenic Astronomical Society (Hel.A.S.) where he served as Secretary (1994-1998) and as President (1998-2002). He served as Member (1986-1990) and as Chairman (2001-2005) of the Greek National Committee for Astronomy.