heliacally , także: helically

They recognized the importance of the heliacally rising constellation as markers for the astrological ages and claimed that knowledge of this phenomenon had been known for thousands of years previously.

During the summer, when Sirius rises heliacally, only twelve of these divisions of the sky can be seen rising during the hours of darkness, and it was this that led to the twelve-hour division of the night.

The Western sidereal astrologer, Cyril Fagan, has speculated that the planets all rose heliacally at these degrees in the year of the erection of an important temple to the Babylonian god Nabu in the year 786 BC, but this is still very speculative.

Because a new decan also appears heliacally every ten days (that is, every ten days, a new decanic star group reappears in the eastern sky at dawn right before the Sun rises, after a period of being obscured by the Sun's light), the ancient Greeks called them dekanoi (pl.