Heliacal rising

[6] The same star will reappear in the eastern sky at dawn approximately one year after its previous heliacal rising.

For stars far from the ecliptic, the period is somewhat different and varies slowly, but in any case the heliacal rising will move all the way through the zodiac in about 26,000 years due to precession of the equinoxes.

For example, the North Star (Polaris) is not visible in Australia and the Southern Cross is not seen in Europe, because they always stay below the respective horizons.

The Sumerians, Babylonians, Egyptians, and Greeks all used the heliacal risings of various stars for the timing of agricultural activities.

The ancient Egyptians appear to have constructed their 365-day civil calendar at a time when Wep Renpet, its New Year, corresponded with Sirius's return to the night sky.

The Egyptians also devised a method of telling the time at night based on the heliacal risings of 36 decan stars, one for each 10° segment of the 360° circle of the zodiac and corresponding to the ten-day "weeks" of their civil calendar.

To the Māori of New Zealand, the Pleiades are called Matariki, and their heliacal rising signifies the beginning of the new year (around June).

Heliacal rising of Ngauponi, i.e. appearance of the Pleiades by the horizon over an hour before the sun approximately 12 days before the winter solstice, announced we tripantu.