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

This period, measured thus by the heliacal rising of Sothis, is spoken of as the Sothic cycle.

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

The heliacal rising of Orion is at present computed to be about the 6th of July; and about that time it is that he either causes or presages tempests on the seas.

From Discourses on Satire and on Epic Poetry by Dryden, 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

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 Beacon Lights of History, Volume 03 Ancient Achievements by Lord, John

The Egyptians had, at an early period, observed that the rising of the Nile coincided with the heliacal rising of Sirius, the Dog-star, and hence they very plausibly referred it to celestial agencies.

From History of the Intellectual Development of Europe, Volume I (of 2) Revised Edition by Draper, John William