Definition of heliacal rising in US English:

heliacal rising


  • The rising of a celestial object at the same time or just before the sun, or its first visible rising after a period of invisibility due to conjunction with the sun. The last setting before such a period is the heliacal setting.

    • ‘The result of this was that the dates of the heliacal rising of Sirius and the flooding of the Nile shifted through the months on a cycle that took 1,461 years to complete.’
    • ‘They were able to calculate that the Sun took 365 days to complete its cycle by noting the time between one heliacal rising of Sirius and the next.’
    • ‘As Venus moves ahead of the Sun, she eventually becomes visible again in the east, in her heliacal rising shortly before sunrise.’
    • ‘During the period of the development of the calendar, the heliacal rising of Sirius coincided with the summer solstice, both of which announced the annual inundation of the Nile, the central focus of the agricultural year.’
    • ‘Another factor is that at the rising of the Sun stars inside this area are within the boundaries of invisibility from which they are yet to be released in their heliacal rising.’