The sky was really important to the ancient Egyptians. By carefully observing and tracing the movements of the celestial bodies across the dome they knew when the seasons were changing, when to plant crops and when to harvest. The presence of stone circles at Nabta Playa, in the 5th millennium BCE, show the importance of astronomy to the religious life of ancient Egypt even in the prehistoric period. The circular stone structure at Nabta is one of the world’s earliest known archeoastronomical devices. Research suggests that it may have been a prehistoric “calendar” marking the summer solstice.
By the time the historical Dynastic Period began in the 3rd millennium BCE, the 365 day period of the Egyptian calendar was already in use, and the observation of stars was important in determining the annual flooding of the Nile. The Egyptian pyramids were carefully aligned towards the pole star, which, because of the precession of the equinoxes, was at that time Thuban, a faint star in the constellation of Draco, and the temple of Amun-Ra at Karnak was aligned on the rising of the midwinter Sun.
As in most early cultures, the patterns and behaviors of the sky led to the creation of a number of myths to explain the astronomical phenomena. For the Egyptians, the practice of astronomy went beyond legend. Huge temples and pyramids were built with specific astronomical orientations. Thus astronomy played a considerable part in fixing the dates of religious festivals and determining the hours of the night, and temple astrologers were especially adept at watching the stars and observing the conjunctions, phases, and risings of the Sun, Moon and planets.The constellation system used among the Egyptians also appears to have been essentially of native origin.
One of the most important Egyptian astronomical texts was the Book of Nut, going back to the Middle Kingdom or earlier.
Beginning with the 9th Dynasty, ancient Egyptians produced ‘Diagonal star tables’ (2160 to 2025 BC), known as 'star charts’ or 'star calendars’.
Such charts decorated the ceilings of tombs and temples. The charts painted in the tombs of Ramses VI and Ramses IX, show that the measurements for fixing the hours of the night were done by seating a man on the ground faced the Astrologer in such a position that the line of observation of the pole star passed over the middle of his head. On the different days of the year each hour was determined by a fixed star culminating or nearly culminating in it, and the position of these stars at the time is given in the tables as in the centre, on the left eye, on the right shoulder, etc. According to the texts, in founding or rebuilding temples the north axis was determined by the same apparatus, and we may conclude that it was the usual one for astronomical observations. In careful hands, it might give results of a high degree of accuracy.
In Egyptian mythology, the principal deities were heavenly bodies. Nut was the sky-goddess, whose body created a vault or canopy over the earth. Nut was the sister and wife of Geb, the god of the earth. They were the parents of Isis, Osiris, Nepthys and Seth. The ancient Egyptians believed that at the end of the day, Nut swallowed the Sun, and gave birth to him again the next morning. The Sun itself was represented by several gods, depending on its position. A rising morning Sun was Horus, the divine child of Osiris and Isis. The noon Sun was Ra because of its incredible strength. The evening Sun became Atum, the creator god who lifted Pharoahs from their tombs to the stars.
The red color of the Sun at sunset was considered to be the blood from the Sun god as he died. After the Sun had set, it became Osiris, god of death and rebirth. In this way, night was associated with death and day with life or rebirth. This reflects the typical Egyptian idea of immortality.
During ancient times, the Moon was never as important to the Egyptians as the Sun, though the Moon was considered by them to be the nightly replacement of the Sun. However, in the relationship between the Moon and the stars, the lunar god can be designated as “ruler of the stars”. The lunar god was either Thoth, the god of wisdom and writing, or Khons, a child Moon god.
The center of Egyptian civilization was the flooding of the Nile River every year at the same time and provided rich soil for agriculture. For the Egyptian priests-astronomers, Sirius was the foundation star. They knew when the flooding occurred using the heliacal rising of Sirius, the brightest star in the night sky, after a 70-day absence from the skies. Sirius was known as Sodpet, and was depicted as a woman with a five-pointed star upon her head. Sopdet is the consort of Sah, the constellation of Orion, near which Sirius appears, and the god Sopdu was said to be their child.
Many Egyptian buildings were built with an astronomical orientation. The temples and pyramids were constructed in relation to the stars, zodiac, and constellations. For instance, some temples were constructed to align with a star that either rose or set at harvest or sowing time. Others were oriented toward the solstices or equinoxes. As early as 4000 B.C., temples were built so that sunlight entered a room at only one precise time of the year.
Altough controversy over Giza’s exact age lingers, some studies turned their attention to the layout of the 3 pyramids on the ground in 10,500 BC, when the alignment of the three pyramids perfect match the three stars of Orion’s belt. The Great Pyramid aligns perfectly to Al Nitak, Second Pyramid to Al Nilam and the Third Pyramid, to star Mintaka. In addition, only in the 10,500 BC epoch will we see that River Nile (which runs through Egypt) actually mirrored the Milky Way in the night skies.
Seemingly, this unique layout was an attempt by ancient Egyptians to build a Heaven on Earth’s ground. Discoveries of ancient Egyptian’s fascination and devotion towards stars (of which they associate with God) tell us that the strong resemblance in the pyramids’ layout with the skies is unlikely to be coincidental. So, when exactly were the Pyramids built? According to Robert Bauval, author of The Orion Mystery, the Pyramids themselves were largely built in 2500 BC, while the ground plan of the 3 pyramids was physically established in 10,500 BC. His conclusion once again stood up to close scrutiny. While some researchers disagreed with the River Nile mirroring the Milky Way back in the 10,500 epoch, others concluded that the exact mirroring occurred in 12,500 BC, not the suggested 10,500 BC.