The Star of Isis

We have just ended the period of summer known as the "dog days." Though most people are familiar with this term, many do not know the correct meaning behind it, but the term has roots that go back all the way to ancient Egypt, and a star called the Star of Isis.

Some folks think that the term dog days refers to weather so hot it isn't fit for a dog. Other think that it is the kind of weather when dogs go mad, from rabies. Neither is correct.

Around here, the dog days are defined as the time between July 3rd and August 1th, and there is an astronomical explanation for it. During this time, the bright winter star Sirius is rising in, or about in conjunction with the Sun, called helical rising. It was once thought that the extreme heat during this time of the year was a combination of effects of both our Sun, and Sirius. Because Sirius is often called the DOG Star, (it resides in the constellation Canis Major, the greater dog,) this period of hot days were called DOG Days. Our ancestors attributed more than just heat to this combination of Sirius and the Sun, they also believed the helical rising could cause droughts, plagues and madness.

Sirius was a very important star to the ancient Egyptians, who called it the Star of Isis, and the Nile Star. About 5,000 years ago, the helical rising of Sirius occurred earlier, around June 25. But when the Egyptians saw Sirius rising just before the Sun they knew it would soon be time for the flooding of the Nile river, around which, all Egyptian life was woven. They depended upon the flooding of the Nile for the fertility of their lands.

It was up to the Egyptian priests, who attended to the calendar, to sight the first rising of Sirius. At the ancient temple of Isis-Hathor at Denderah, is a beautiful statue of Isis, located at the end of an aisle flanked by large columns. The statue was oriented to the rising of Sirius and priests would place a jewel in the goddess' forehead so that the light from the returning star would fall on the gem.

When the Egyptian priests saw the light of Sirius upon the gem on the statue of Isis, they would announce to the people that the New Year had begun. There is an inscription on the temple which states: "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." To the Egyptians, Ra was the Sun god.

During the coming week, you can see Sirius, the Star of Isis, just before sunrise. Look for this bright star rising just above the southeast horizon, the brightest star in Canis Major. When Sirius is low to the horizon it appears to flicker with all the colours of the rainbow and is truly a beautiful sight.

Sirius is the brightest star seen from mid-northern latitudes. As stellar distances go, Sirius is quite close to us, a distance of just 8.7 light years, Among the naked-eye stars, it is the nearest of all, with the exception of Alpha Centauri. Happy Stargazing!