A Photography of Roger CayrelCredit: Jean Mouette /IAP-CNRS-SU

An unpublished video interview (in French) with Roger Cayrel (1925–2021).

Freshly graduated from the École Normale Supérieure (ENS), where Évry Schatzman, a pioneer of French theoretical astrophysics, was his diploma director, Roger Cayrel arrived at the Institut d'astrophysique de Paris (IAP) in 1951 to work on a doctoral thesis under his supervision. The subject he chose, the precise analysis of the chemical composition of the atmosphere of a supergiant star, was very innovative and led him to use complex mathematical tools compared to the capabilities of the mechanical computing machines of the 1950s. Carrying out these operations, tasks that were exclusively assigned to women within the calculation offices set up in astronomy and astrophysics research organisations, was a long and tedious process: a thesis work, for this reason, took at least 4 or 5 years. When IBM France, then located Place Vendôme in Paris, imported the first computer, the IBM 650, into France in 1955 and offered the university community 50 hours of calculation, Roger Cayrel applied and obtained 3 hours. This enabled him, after a few months of programming, to save 2 years on the duration of his thesis. He is thus the first French astronomer to have ever used a computer for calculations for a research project.

This video interview (in French) was conducted on 26 June 2013, in his office at the Paris Observatory, where he spent most of his career, by Denis Guthleben (historian at the CNRS) and Jean Mouette (IAP-CNRS-SU), as part of the IAP's 75th anniversary celebrations. The authors thank Suzy Collin-Zahn (Observatoire de Paris-Meudon) for her friendly support for this interview.


puce  Video interview with Roger Cayrel on the IAP YouTube channel: “Mon départ scientifique à l'IAP”
puce  Academy of Sciences: “In Memoriam Roger Cayrel, correspondant de l'Académie des sciences”.
puce  Paris-Meudon Observatory: “Disparition de Roger Cayrel”
puce  Roger Cayrel on Wikipédia: “Roger Cayrel”

Writing and layout: Jean Mouette
Web writing: Valérie de Lapparent

March 2021

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