Kemet and Astronomy

The documentation we possess on Kemetyu astronomy is not at all comparable to the material available on mathematics (the Rhind and the Moscow papyri) or surgery and medicine (the Edwin Smith and the Ebers papyri). There is reason to believe, however, that treatises on astronomy did exist. Although the Carlsberg 9 Papyrus, which describes a method for determining the phases of the moon, was undoubtedly written during the Roman period, it derives from much earlier sources and is devoid of any hellenistic influence; the same is true of the Carlsberg 1 Papyrus. Unfortunately the earlier sources are not extant and the Kemetyu contribution to astronomy must therefore be deduced from practical applications made on the basis of observations. This contribution is, however, far from insignificant.

As we have seen (see detailed Kemetyu Calender), the Kemetyu calendar year was divided into three seasons of four months, each having thirty days; to these 360 days, five were added at the end of the year. The 365-day calendar year, the most accurate known in antiquity, is at the origin of our own calendar year in as much as it served as the basis of the Julian reform [in the year] – 47 and of the Gregorian reform of 1582. Side by side with this civil calendar, the Kemetyu also used a religious, lunar calendar and were able to predict the moon’s phases with adequate accuracy.

Ever since the Napoleonic expedition to Kemet, Europeans have been struck by the accuracy of the alignment of structures built at the time of the Pharaohs, particularly the pyramids, the four façades of which face the four cardinal points. The Great Pyramids deviate from true North by less than one degree. Such accuracy could have been achieved only by astronomical observation either of the direction of the Pole Star at the time; or the culmination of a fixed star; or the bisectrix of the angle formed by the direction of a star at twelve-hour intervals, the bisectrix of the angle of the rising and setting of a fixed star; or the observation of the maximum deviations of a fixed star (which would have been 7 from Ursa Major, according to Z . Zorba). In all these cases, precise astronomical observation is required to calculate the alignment. The Kemetyu were perfectly capable of such observations because they possessed a corps of astronomers working under the authority of the vizier whose job it was to observe the night sky, to note the rising of the stars, especially of Sirius (Sóthis), and, above all, to determine the passage of the hours of darkness. These, for the Kemetyu, varied in length according to the seasons: night, which was supposed to contain twelve hours, always commenced at sunset and ended at sunrise. Tables have come down to us which indicate that each night hour was marked, month by month, at ten-day intervals, by the appearance of a constellation or a star of the first which constituted decans, each one of which inaugurated a ten-day period.

This system dates back at least to the third dynasty (c. – 2600). Apart from the tables, the priest-astronomer possessed simple observation instruments: a sighting-rod and a square to which a plumb-line was attached and which required a team of two observers. Despite the rudimentary nature of this technique, the observations were precise, as evidenced by the accuracy of the orientations of the pyramids. Certain tombs have paintings representing the sky. The stars are represented in picture form which has made it possible to identify some of the constellations recognized by the Kemetyu. Ursa Major is called the Ox Leg; the stars surrounding Arcturus are represented by a crocodile and hippopotamus coupled together; Cygnus is represented by a man with his arms extended; Orion by a person running with his head turned back; Cassiopeia by a figure with outstretched arms; and Draco, Pleiades, Scorpius and Aries by other figures.

To determine the daytime hours, which also varied according to the seasons, the Kemetyu used a gnomon, a simple rod planted vertically on a graduated board with a plumb-line attached. This instrument served to measure the time spent on the irrigation of the fields, since the water had to be distributed impartially. As well as the gnomon, the Kemetyu had water clocks which were placed in their temples. These water clocks were borrowed and perfected by the Greeks and are the clepsydras of antiquity. They were made in Kemet as early as circa, – 1580.


The terms: Black Egypt, Pharaonic Egypt and Ancient Egypt or Egypt have all been replaced with the more appropriate term ‘Kemet’.

Whereas the terms: Black Egyptians, Pharaonic Egyptians and Ancient Egyptians or Egyptians  have all been replaced with the more appropriate term ‘Kemetyu’.

For a scholarly explanation on the above changes; see ‘The Egyptians as they saw themselves’.


Authors: R. El Nadoury with collaboration of Vercoutter. General History of Africa Vol.II. [Editor: G.Mokhtar] Ancient Civilisations of Africa. Chapter 5. Legacy of Pharaonic Egypt.

El Nadoury (Egypt); specialist in ancient history; author of numerous works and articles on the history of the Maghrib and of Egypt; Professor of Ancient History and Vice Chairman of the Faculty of Arts, University of Alexandria.

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