From 1931 to 1956, Griaule studied the Dogon in field missions ranging from several days to two months in 1931, 1935, 1937 and 1938 In late 1946, Griaule spent a consecutive 33 days in conversations with the Dogon wiseman Ogotemmeli, the source of much of Griaule and Dieterlen's future publications. They reported that the Dogon believe that the brightest star in the night sky, Sirius ("Sigi Tolo" or "star of the Sigui"), has two companion stars, "Pō Tolo" (the Digitaria star), and "ęmmę ya tolo", (the female Sorghum star), respectively the first and second companions of Sirius A. Sirius, in the Dogon system, formed one of the foci for the orbit of a tiny star, the companionate Digitaria star. When Digitaria is closest to Sirius, that star brightens: when it is farthest from Sirius, it gives off a twinkling effect that suggests to the observer several stars. The orbit cycle takes 50 years. They also claimed that the Dogon appeared to know of the rings of Saturn, and the moons of Jupiter.