Sirius Puzzles

Sirius is the brightest star in the sky, which makes its image particularly difficult to obtain, even with the most powerful telescopes. The astrophysicist Jean-Marc Bonnet-Bidaud relies on observations by the Greek astronomer Ptolemy and Chinese astronomical texts to hypothesize that Sirius changed colour at the beginning of our era. This change in colour could be explained by the presence of one or two "companion stars" orbiting Sirius.
Jean-Marc Bonnet-Bidaud travels to the largest observatories of the planet (Pic du Midi, La Silla in Chile), and also among the Dogon of Mali for his research. Sirius is Sigi Tolo, the star celebrated in the Sigui, the most important Dogon ceremony that takes place every sixty years.
Jean-Marc Bonnet-Bidaud observed the joint rising of the sun and Sirius, as the Dogon have always described it, together with ethnologists Jean Rouch and Germaine Dieterlen. He interviewed about the primordial role of this star in the Dogon cosmogony, wondering how the Dogon became aware of this star and its companion in the absence of any observation equipment.