Ancient Egyptian astrology is not the same astrology we use today, although there are a few links that tie them together. But ancient astrology in general was used a little differently than the way we use astrology today.

For the most part, astrology in the ancient times was used more for predicting planetary shifts that affected nature’s cycles. Like how the moon affects the tide. This helped with planning agriculture, predicting droughts or famines, and things like that.

There was of course a fortune-telling side to it – especially centered around looking for auspicious times for rituals and deciphering omens and things like that.

The branch of astrology in the ancient world that dealt with individual fates usually centered around that of the king. And as with everything else, the natural phenomena observed were explained through myths and legends.


The ancient Egyptians divided the year into 12 months of 30 days each, and then each month was divided into three parts of 10, each called a decan or decante. The literal meaning of the word decan is “ten days apart” or “group of ten”.

In ancient Egyptian astrology, each decan was based on a small constellation of stars. Every 10 days, a new constellation would have a heliacal rising. A total of 36 decans were observed, . And so 36 x 10 = 360 days. The extra five days were added at the end in the ancient Egyptian calendar.

The beginning of the cycle of the decans started with the heliacal rising of the star Sirius, called Sothis in Greek.

Helical rising, by the way, means the rising of a celestial object at the same time as 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.

These decans were painted on the inside of coffins and ceilings of tombs as far back as the 10th Dynasty of Egypt.

With modern astrology, the zodiac is divided into 12 signs, and each sign is divided into 3 decan – so basically your star sign has a first, second and third decan. If you were born in the first 10 days of your sign, it would mean you are of the first decan of whatever that sign is.

So if you were born on the 30th of July, you would be a Leo of the first decan. Although a third decan Leo would share your sign’s characteristics, there would be slight differences in those characteristics.


There are a few ancient Egyptian astrological works that fall under the term The Book of the Sky: The Book of the Day, The Book of the Night, and The Book of Nut (originally called “Fundamentals of the Course of the Stars”).

The books are actually more like pictures and paintings found in the tombs of royals and nobles such as Seti I, Ramesses IV, Ramesses VI and Mutirdis (a God’s Wife of Amun).

Many of them center around the goddess Nut, especially in the Book of Nut.

The main theme of the Book of Nut is how the sun was birthed by the goddess Nut as goddess of the sky, every morning, and then traveled the length of her body up towards her mouth, then swallowed by her every night.

Another part of it shows her as a mother of the stars, and her husband Geb is angry that she swallows her own children every night. Their father Shu intercedes and tells Geb that it is actually a good thing because then they get to experience rebirth.

The Book of the Day’s theme is more about listing gods and goddesses and showing the sun’s daytime journey through the sky. And with the Book of the Night, we get to the nighttime journey of the sun, which is a main theme in almost all the funerary texts. It is similar to the Book of Gates, which also maps out the 12-hour nocturnal voyage through the underworld.


The more relatable Egyptian astrology comes to us from Hellenic Egypt, when the Greeks were ruling. Before Alexander the Great had conquered Egypt in 332 BCE, Egypt had been invaded by the Persians who brought with the the influence of Mesopotamian astrology.

Mesopotamian astrology mixed with the ancient Egyptian decantic style and produced the zodiac along with the eclipses and planets, divided into the 36 decans of the 12 signs. This is what we call horoscopic astrology.

During the first century ADE in the city of Alexandria, a writer and astrologer named Ptolemy lived and worked. He is considered one of the founders of modern Western astrology today.

His work titled Tetrabiblos is one of the most important astrological texts. It was translated from Arabic to Latin and then it circulated all over Medieval Europe.

The Zodiac of Dendera, now held at the Louvre, is a beautiful example of this melange of different astrological traditions combining together – the Babylonian, Egyptian and Greek.

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