The memory of Jean-François Denisse honored by his peers

Past Director of the Paris Observatory, past President of the of the CNES [1], founder of the INAG (ancestor of the INSU-CNRS [2]), member of the Academy of Sciences … these are just a few of the most prestigious duties of the charismatic Jean-François Denisse.

The skills of this visionary leader and outstanding organiser were honoured during a commemorative ceremony which took place at the Paris Observatory on the 13th of May 2015, in the presence of Claude Catala, President of the Paris Observatory, Sébastien Candel, vice-president of the Academy of Sciences, Denis Mourard, scientific director for astronomy of the INSU-CNRS, Fabienne Casoli, CNES deputy director for strategy, James Lequeux, emeritus astronomer at the Paris Observatory, Françoise Combes, astronomer at the Paris Observatory and member of the Academy of Sciences.

« He is responsible for virtually the whole of our discipline (…) and thus for the central role of France, and in particular of the Paris Observatory, in modern international astronomy » emphasized Claude Catala during a stirring opening tribute
During the opening years of the 1950s, at the Ecole Normale Supérieure (ENS), Jean François Denisse, encouraged by Yves Roccard, then director of the physics laboratory, laid the foundations of radio-astronomy.
It was then that Jean-François Denisse created the Nançay radio-astronomical observatory, on a 150 ha terrain bought by the ENS, and began to install the large instruments which are still operational ; the first instrument was the large radioheliograph, commissioned in 1956.
In 1963, he succeeded André Danjon as the head of the Paris Observatory, which he directed until 1968. The Large Nançay radiotelescope was built during his mandate ; it was inaugurated in 1965 by General de Gaulle in person, and this year is its 50th anniversary.

An impressive track record

His track record as Director of the Paris Observatory is truly impressive : during his mandate, the Observatory went through one of its most significant periods of expansion and development, during which its staff was virtually tripled.
While this success was certainly a consequence of the policy for the development of research which France was pursuing at that time, Jean-François Denisse was able exploit it fully and efficiently.
The construction of the A and B buildings, on the Paris site, is also due to him. « Knowing the current difficulties associated with new building projects, one cannot but be impressed by these products of the 1960s realized under the responsibility and leadership of Jean-François Denisse. », noted Claude Catala.
In 1963, right at the start of his mandate as head of the Observatory and even as radio-astronomy was being born t Nançay, Jean-François Denisse, together with Jean-Louis Steinberg, created the space-radioatronomy section.
This was a capital event for the development of the Paris Observatory, since the space radioastronomy section then became the DESPA, the department of space research, which subsequently became the LESIA [3] that we know today, thus enabling the Paris Observatory to play a major role in space research.
In 1967, Jean-François Denisse was the initiator and founder of the INAG. He was the first director of this institution, which, in 1985, became the INSU.
Finally, from 1967 to 1973, Jean-François Denisse was one of the first presidents of the CNES, and was elected to the Academy of Sciences in 1967.
At the initiative Françoise Combes, the Paris Observatory has decided to honour the memory of Jean-François Denisse by associating his name with a conference room on the Parisian site.