Heliacal Rising of Stars

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Heliacal Rising of Stars

 

the day or, more precisely, the moment of a star’s first appearance of the year above the eastern horizon against the background of daybreak. (For several months before its heliacal rising a star is in the daytime sky but is invisible.) The moment of the heliacal rising of a star depends on its coordinates and the geographic coordinates of the place of observation. The moments of the heliacal rising of a star (Sirius) enabled astronomers in ancient Egypt to predict the times of the Nile’s spring floodings, which were important for determining when agricultural work should be done.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.