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

---

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

The heliacal rising of a constellation is when it comes from under the rays of the sun, and begins to appear before daylight.

From Discourses on Satire and on Epic Poetry by Dryden, John

The more precise fixing of new year's day was accomplished through observation of the time of the so-called heliacal rising of the dog-star, Sirius, which bore the Egyptian name Sothis.

From A History of Science — Volume 1 by Williams, Edward Huntington

On the ceiling of the Memnonium at Thebes the heliacal rising of Sirius is represented under the form and name of Isis.

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

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