Star of the Nile

space.com

In ancient Egypt, the New Year began with the return of Sirius. It was, in fact, the "Nile Star" or the "Star of Isis" of the early Egyptians.

Interestingly, some 5000 years ago, this "heliacal rising" (appearing to rise just prior to the sun) occurred not in August, as is the case today, but rather on, or around June 25. When they saw Sirius rising just before the sun, they knew that the "Nile Days" were at hand. Its annual reappearance was a warning to people who lived along the Nile River. The star always returned just before the river rose, and so announced the coming of floodwaters, which would add to the fertility of their lands. People then opened the gates of canals that irrigated their fields.

Priests, who were the calendar keepers, sighted the first rising of the Dog Star from their temples.

At the temple of Isis-Hathor at Denderah is a statue of Isis, which is located at the end of an aisle lined by tall columns. A jewel was placed in the goddess' forehead. The statue was oriented to the rising of Sirius, so that the light from the returning Dog Star would fall upon the gem. When the priests saw the light of the star shining upon the gem for the first time, they would march from the temple and announce the New Year.

In the temple appears the inscription: "Her majesty Isis shines into the temple on New Year's Day, and she mingles her light with that of her father Ra on the horizon."