Dog days sometimes used for the lethargic summer markets. Various computations of the dog days have placed their start anywhere from 3 July to 15 August and lasting for anywhere from 30 to 61 days. They may begin or end with the cosmical rising or heliacal rising of either Sirius in Canis Major or Procyon (the "Little Dog Star") in Canis Minor and vary by latitude, not even being visible throughout much of the Southern Hemisphere. Sirius observes a period of almost exactly 365¼ days between risings, keeping it largely consistent with the Julian but not the Gregorian calendar; nonetheless, its dates
Ancient astronauts Temple's 1976 book, "The Sirius Mystery "argues that the Dogon people of northwestern Mali preserved an account of extraterrestrial visitation from around 5,000 years ago. He quotes various lines of evidence, including advanced astronomical knowledge inherited by the tribe, descriptions, and comparative belief systems with ancient civilizations such as ancient Egypt and Sumer. His work draws heavily on the studies of cultural anthropologists Marcel Griaule and Germaine Dieterlen. His conclusions have been criticized by scientists, who point out discrepancies within Temple's account, and suggested that the Dogon may have received some of their astronomical information recently, probably from European sources,