The measurement of the diameter of Canopus and the detection of spots on its surface, were carried out by an international team led by Armando Domiciano de Souza, astronomer at the Laboratory Fizeau (CNRS, Université of Nice Sophia-Antipolis, Observatoire of the Coast d' Azure-KNOWLEDGE). They used AMBER instrument installed in the ESO Broad Very Telescopes Interferometer in Paranal in Chile. These results make it possible to better include/understand the phenomena of convection during a phase of stellar evolution still badly known: the passage of the red supergiant stage to that of a blue supergiant blue. This work will be published soon in the review Astronomy and Astrophysics Letters.