Egyptians therefore held their New Year celebration at the time of this heliacal
rising of Sirius.
Since Sirius "begins its heliacal
rise to reach its akme" in the month of Tir (June 21-July 21), "one of the most torrid months of the year in Iran" (p.
Julius Caesar held that the heliacal
rising of the Pleiades (meaning the first date each year when they could be seen in the east before sunrise) marked the beginning of summer.
Luft's analysis shows that this festival was dated by the lunar calendar and occurred before the heliacal
rising of Sothis.
In traditional Maori society, a watchful eye is kept on the evening sky following the heliacal
rising of Matariki to spot the appearance of the next new Moon.
The line coincides with summer solstice on Mars 500,000 years ago, and the same vista incorporates the heliacal
rising of Earth.
The ancient Egyptians marked the start of their new year by the heliacal
rising (first appearance in the glow of sunrise) of Sirius.
Because the count was roughly a quarter-day short of the true length of the year, the heliacal
rising of Sirius drifted through the solar calendar and did not recur on the first day of the year until 1,461 of those 365-day years had elapsed.
rising (in the eastern skies) to an astrologer.
Other sources give the date of discovery in 1006 as May 1st and of heliacal
setting as November 26th, adding the detail that the star was located in the 3rd degree east of Di - a measure of right ascension.
They assigned that seasonally significant heliacal
rising to July 3rd, the eve of American Independence Day.
These chunks of computer instructions can be included in earlier programs - for telescopic limiting magnitudes (S&T: November 1989, page 522), heliacal
rising (S&T: September 1985, page 261), lunar occultations (S&T: January 1993, page 89), and extinction angles (S&T: April 1987, page 426) - to yield more accurate results.