heliacal rising

British  

/ hɪˈlaɪəkəl /

noun

1. the rising of a celestial object at approximately the same time as the rising of the sun

2. the date at which such a celestial object first becomes visible in the dawn sky

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Etymology

Origin of heliacal rising

C17: from Late Latin hēliacus relating to the sun, from Greek hēliakos, from hēlios the sun

Example Sentences

They approximated to the truth in reference to the solar year, by observing the equinoxes and solstices, and the heliacal rising of particular stars.

From The Old Roman World, : the Grandeur and Failure of Its Civilization. by Lord, John

According to an extremely ancient belief it was the goddess Hathor Isis-Sothis who caused the inundation of the Nile which, according to the inscriptions, coincided with the heliacal rising of Sirius.

From The Fundamental Principles of Old and New World Civilizations by Nuttall, Zelia

Dog-days, the name applied by the ancients to a period of about forty days, the hottest season of the year, at the time of the heliacal rising of Sirius, the dog-star.

From The New Gresham Encyclopedia Volume 4, Part 1: Deposition to Eberswalde by Various

It seems to have been considered of great importance in ancient Egypt, as its heliacal rising announced that of Sirius, which heralded the annual rising of the Nile.

From Astronomical Curiosities Facts and Fallacies by Gore, J. Ellard

In Egypt, another reason was, that then the Nile began to overflow, at the heliacal rising of Sirius.

From Morals and Dogma of the Ancient and Accepted Scottish Rite of Freemasonry by Pike, Albert