Adjective
Emerging from the light of the sun, or passing into it; rising or setting at the same, or nearly the same, time as the sun.
Source: Webster's dictionarythe heliacal rising of the Dog Star Source: Internet
the heliacal or Sothic year is determined by the heliacal rising of Sothis (the Egyptian name for the Dog Star) Source: Internet
The Romans celebrated the heliacal setting of Sirius around April 25, sacrificing a dog, along with incense, wine, and a sheep, to the goddess Robigo so that the star's emanations would not cause wheat rust on wheat crops that year. Source: Internet
It probably derives from plein ('to sail') because of the cluster's importance in delimiting the sailing season in the Mediterranean Sea : 'the season of navigation began with their heliacal rising '. Source: Internet
The heliacal rising of the next decan star marked the start of a new civil week, which was then ten days. Source: Internet
The term heliacal circle is used for the ecliptic, which is in the center of the zodiacal circle, conceived as a band including the noted constellations named on mythical themes. Source: Internet