Introduction
Since the end of the last Ice Age - around 12,000 years ago - the Earth's surface has remained virtually unchanged: divided into seven continents covered with ice, rock or vegetation, depending on altitude and latitude, and separated by vast expanses of ocean. The Natural Earth imagery uses light and shadow effects to depict continental and oceanic landforms, and color gradations to depict the Earth's surface devoid of any human influence - just as it was at the very beginning of the Neolithic period, in particular.
In those remote times, the Earth's surface was topped by a celestial vault dotted with thousands of points of light whose relative movements were recorded by nomadic peoples who grouped them into categories: the Sun and Moon on the one hand, the stars and planets on the other. This was followed by spatial location (solstitial and cardinal points) and temporal divisions (days, seasons, years), as witnessed by the many rock and architectural remains left by the peoples and civilizations of Antiquity, which the development of modern tools leads to decrypt.
Model of star visibility
As their discoveries have grown, archaeologists have built up vast databases of architectural, textual, and pictorial remains, some of which provide us with information about the astronomical knowledge of a people or civilization: the name given to a particular star, the recording of its positions in the local sky over a given period of time, the possible periodicity of its movement, etc.
Identifying each of these stars with the objects that fill our sky, understanding how the earliest calendars worked, and determining the astronomical source of orientation of a particular monument require the prior development of a model of star visibility to the naked eye in the night or twilight sky overlooking each of the ancient observation sites.
This model, developed in the context of my doctoral thesis, combines various astrometric parameters (related to the positioning of celestial bodies in the local sky) and photometric parameters (related to the human eye's ability to distinguish an object of a given magnitude against a background sky of varying brightness). Applied to ancient Egypt, this model has given rise to several innovative archaeoastronomy software programs.
Application to ancient Egypt
Applied to ancient Egypt, the model of star visibility to the naked eye developed in the context of my doctoral thesis has given rise to two innovative archaeoastronomy software programs. One allows the precise determination of the heliacal rising and setting dates of any star visible to the naked eye, the second identifies the astronomical source of orientation of any monument.
The use of both software programs has enabled the resolution of numerous issues: the identification of the astronomical source of orientation of the pyramids of the Old Kingdom, the working principle of the star clocks decorating the lids of sarcophagi dating from the end of the First Intermediate Period and the Middle Kingdom, their filiation with the astronomical ceilings of the New Kingdom, the identification of the Egyptian decans with certain bright stars of our sky, and the reasons for the reorientation of the main axis of the Temple of Isis at Dendera.
All of these results — and many others — have been published in various Egyptology journals and in the specialized press, and have been the subject of numerous conferences/shows and TV documentaries. The software programs designed on the basis of the model of star visibility to the naked eye are also available to you in the Client Area.
