Sirius its constellation, Canis Major (Greater Dog). The heliacal rising of Sirius marked the flooding of the Nile in Ancient Egypt and the "dog days" of summer for the ancient Greeks, while to the Polynesians in the Southern Hemisphere the star marked winter and was an important reference for their navigation around the Pacific Ocean. The brightest star in the night sky, Sirius is recorded in the earliest astronomical records. Its displacement from the ecliptic causes this heliacal rising to be remarkably regular compared to other stars, with a period of almost exactly 365.25 days holding it constant relative to the
Dog days even recorded the belief that the return of the bright star was responsible for bringing heat and fever with it; it was also associated with sudden thunderstorms. In Homer's "Iliad", probably composed in the but representing an earlier tradition, Achilles' approach towards Troy, where he will slay Hector, is illustrated through an extended metaphor about the baleful effects attending the return of Sirius: The rising of Sirius during this period has been calculated as 19 July (Julian). Writing about the same time, Hesiod, however, considered the worst and hottest part of the summer to be the days "before" Sirius returned