Tuesday, December 16, 2008
The Egyptian gods and goddesses were numerous and were pictured in many reliefs. Certain gods were seen in the constellations, and others were represented by actual astronomical bodies. The constellation Orion, for instance, represented Osiris, who was the god of death, rebirth, and the afterlife. The Milky Way represented the sky goddess Nut giving birth to the sun god Re. The stars in Egyptian mythology were represented by the goddess of writing, Seshat, whilst the Moon was either Thoth, the god of wisdom and writing, or Khons.
The horizon had great significance to the Egyptians, since it was here that the sun would both appear and disappear daily. The sun itself was represented by several gods, depending on its position within the sky. A rising morning sun was associated with Horus, the divine child of Osiris and Isis. The noon sun was Re because of its incredible strength. The evening sun became Atum, the creator god who lifted pharaohs from their tombs to the stars. The redness of the setting sun was considered to be the blood from the sun god as he "died" and became associated with Osiris, god of death and rebirth. In this way, night became to be associated with death, and the daytime with life or rebirth. This reflects the typical Egyptian idea of immortality.
Astronomy for use in daily lifeThe centre of Egyptian civilisation was the Nile. Flooding every year at the same time, it provided rich soil for agriculture. The Egyptian astronomers, who were actually priests, recognised that the flooding always occurred at the summer solstice, which also just happened to be when the bright star Sirius rose before the sun. By interpreting and using this information, the priests were subsequently able to predict the annual flooding, a skill which in turn rendered them considerable power. The year was divided into twelve 30 day months, followed by a five day feast period. Because the Egyptian calendar did not have leap years, it cycled through the seasons completely every 1460 years. The period that elapsed between these risings is known as the "sothic cycle". Over ancient Egypt's history, the months completely rotated through the seasons at least twice due to this quarter day discrepancy.
Although the Egyptians knew of this quarter-day error, they still maintained their 365 day calendar for ceremonial reasons.
Many Egyptian buildings were built with an astronomical orientation. The temples and pyramids were constructed in relation to the stars, and in different towns throughout the country, buildings would have a different orientation based on the specific religion of the place. Temples were often built so that sunlight entered a room at only one precise time of the year.Astronomy for use in datingOne of the hardest tasks of the modern Egyptologist is to attempt to tie together, in some sort of chronological order, the pieces of evidence from burials, tombs, temples, archaeological excavations and a range of other sources. The surviving records of observations of the "heliacal rising" of the dog star Sirius serve as the lynchpin of the Egyptian calendar and its essential link with Ancient Egyptian chronology as a whole.
The "Sothic rising" of Sirius coincided with the beginning of the solar year only once every 1456 - 1460 years (because of precession of the equinoxes and proper motion of Sirius it was usually a few days earlier than the 1460 years that the ancients had predicted). This rare event took place in AD 139 during the reign of the Roman emperor Antonius Pius, and was commemorated by the issue of a special coin at Alexandria. Earlier heliacal risings would have taken place in around 1321-1317 BC and 2781-2777 BC.
Astrological terms and beliefs in ancient Egypt
The term used to refer to the annual ten day period when Sirius the "dog star" would rise above the horizon at dawn.
The goddess Sopdet was the personification of the "dog star", known to the Greeks as Seirios (Sirius). Sopdet was the most important star to the Ancient Egyptians, and was known as a decon. Together with her husband Sah (Orion), and her son Soped, Sopdet formed part of a divine triad which paralleled that of Osiris, Isis and Horus.
The god Sah was the personification of the constellation later known as Orion. Sah was described as "the glorious soul of Osiris" and formed a divine triad with the dog star Sopdet and their son Soped, god of the "eastern border".
The son of Sopdet and Sah, Soped was a hawk-god and personification of the eastern frontier of Egypt.
Ancient Egyptian star-gods. Deities known as the "imperishable ones" personified the ever visible circumpolar stars in the north of the sky.
The Ancient Egyptians would divide night sky into 36 groups of star-gods or constellations. These groups were known as decons, and each specific decan rose above the horizon at dawn for a period of ten days every year. The brightest and most important of these was the dog star Sirius, otherwise known as the goddess Sopdet. The ceilings of many royal tombs depict the night sky as groups of star-gods or decons, moving across the sky in boats.
The earliest detailed texts relating to astronomy are the "diagonal calendars" or star clocks. These were painted on the wooden coffin lids of the early Middle Kingdom, and also the Late Period. These calendars consisted of 36 columns which listed the 36 decons and detailed the rising period of each. This calendar system was flawed by its failure to take into account that the Egyptian year was always approximately six hours short. This would add up to a shortcoming of around ten days every 40 years.
From as early as the Middle Kingdom, the Egyptians recognised five of the planets: Jupiter ("Horus who limits two lands"), Mars ("Horus of the horizon", or "Horus the red"), Mercury (Sebegu, a god associated with Seth), Saturn ("Horus, bull of the sky") and Venus ("the one who crosses", or "god of the morning"). The Egyptians portrayed the planets as deities sailing across the heavens in barques, and they were known as the "stars that know no rest".
The belief that the stars could influence human destiny does not appear to have reached Egypt until the Ptolemaic period. By the 1st century AD the Babylonian zodiac had been adopted. This zodiac can be seen represented on the ceiling of the chapel of Osiris on the roof of the temple of Hathor at Dendera.
The "instrument of knowing" was a sighting tool made from the central rib of a palm leaf and was similar in function to an astrolobe. The merkhet was used for aligning the foundations of the pyramids and sun temples with the cardinal points, and was usually correct to within less than half a degree. It was developed around 600 BC. and uses a string with a weight on the end to accurately measure a straight vertical line, much like a plumb bob. A pair of merkhets were used to establish a north-south line by lining them up with the pole star. This allowed for the measurement of night-time hours as it measured when certain stars crossed a marked meridian on the sundial.
Literally meaning "the stretching of the cord", the Pedj Shes was a ceremony performed to work out the correct alignment for the building of temples and pyramids. It relied on the sightings of the constellations of Orion and Ursa Major (the great bear) and used the sighting instrument called a "merkhet" ("instrument of knowing").
Discover why "sothic dating" has such importance in ancient Egypt's modern day chronology >>