heliacal rising(redirected from Heliacal setting)
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Related to Heliacal setting: Heliacal rising
1. (Astronomy) the rising of a celestial object at approximately the same time as the rising of the sun
2. (Astronomy) the date at which such a celestial object first becomes visible in the dawn sky
[C17: from Late Latin hēliacus relating to the sun, from Greek hēliakos, from hēlios the sun]