Fourteen years. Such was the time needed to turn a simple idea
- to study, by means of appropriate methods, the sky of ancient Egypt -
into a full thesis subject, of which the examination of the manuscript and the defense
brought together for the first and only time renowned Egyptologists and Astronomers.
It was on May 21, 2008. On that very day, Toulouse was the capital of interdisciplinarity.
I prepared my doctoral thesis on the theme of ancient Egyptian astronomy under the direction of Robert Nadal, an astronomer specializing in ancient Greece, and then of Sylvie Roques, CNRS Research Director, at the Laboratoire d'Astrophysique de Toulouse-Tarbes (LATT), a joint research unit of the University Paul Sabatier of Toulouse and of the CNRS (UMR 5572), which soon became the Institut d'Astrophysique et de Planétologie (IRAP, UMR 5277).
Thesis Title: Design of a model of star visibility to the naked eye. Application to the identification of the old Egyptian decans.
Summary : On the interior lid of sarcophagus, on the outer surface of water clocks, on the ceiling of temples and tombs dating from the year 2100 to the year 50 BC and built all along the Nile Valley, between Alexandria and Aswan, there are twenty stellar clocks and eighty star lists in the order of their heliacal risings, night risings or culminations in the southern meridian. Because their heliacal risings occurred at ten days intervals, these stars have been termed as decanal. Their identification with the stars visible to the naked eye (of apparent magnitude lower than or equal to 6) of the Hipparcos Catalogue required:
- 1. the building of a database from the one hundred archaeological remains (stellar clocks and star lists) discovered to date;
- 2. the establishment of a catalog of the 90 old Egyptian decans, along with the meaning of their respective hieroglyphic names;
- 3. the study of the stellar arrangements characterizing every one of the one hundred remains in order to determine the time conditions (epoch of the decanal star lists) and the spatial conditions (latitude of the site of stargazing the decanal stars) of observation of the decanal stars in the sky of ancient Egypt;
- 4. the study of the various writings stating the helical rising of Sirius in the past of Egypt (el-Lahun papyrus, Ebers Calendar, Text of foundation of the temple of Hathor at Dendera, etc..) in order to determine the optical conditions of observation of the decanal stars in the sky of ancient Egypt;
- 5. the design of a visibility model of stars which can be seen with the naked eye in the twilight and night sky of ancient Egypt. This model combines various astrometric parameters (proper motion of stars, precession of the world axis, etc..) and various criteria of visibility of an object in the sky (increasing of the apparent magnitude under the effect of atmospheric extinction, brightness of the sky where the object is, visual acuity of the observer);
- 6. the study of the sequence of appearances and culminations of stars in the temporal, spatial and optical conditions set, in relationship with the one hundred lists we have;
- 7. the application of various astronomical criteria (apparent magnitude, color index, time of rising or culmination of each star) and egyptological criteria (hieroglyphic meaning of the name of each decan and celestial imagery associated) to each sample of candidate stars to the Egyptian decans which the model provided;
- 8. the checking of the resistance of the identifications proposed to realistic changes in the historical epoch, in the latitude of the site of observation, in the local weather conditions and in the visual acuity of the observer.
This research work allowed to draw up a map of the southern sky of ancient Egypt. He also helped to refine the dates of the beginning of the reign of several pharaohs (Sesostris III, Amenhotep I and Tuthmosis III), to better understand the division of time in hours, etc.
Thesis defending : My thesis defending was held on May 21, 2008 at the Laboratoire d'Astrophysique de Toulouse-Tarbes before a jury made up with six astronomers, physicists and one Egyptologist:
- Georges Balmino, CNES Distinguished Engineer, Laboratory of Terrestrial and Planetary Dynamics, Observatoire Midi-Pyrenees;
- Alain Blanchard, Professor at the University Paul Sabatier of Toulouse;
- Nicole Capitaine, Astronomer at the Observatoire de Paris;
- Leo Depuydt, Professor of Egyptology at Brown University;
- Daniel Egret, President of the Observatoire de Paris;
- Sylvie Roques, CNRS Research Director, Laboratoire d'Astrophysique de Toulouse-Tarbes, Observatoire Midi-Pyrénées;
- David Valls-Gabaud, CNRS Researcher, GEPI, Observatoire de Meudon.
My thesis defending resulted in the granting of a Ph.D. in Astronomy of the University of Toulouse.
Documents available on download:
- This thesis work led to the writing of twleve articles available on download within the section entitled AstroEgypto.
- The slide show of my PhD thesis defense can be downloaded here.
- The manuscript of my PhD thesis is available on free download on the TEL multidisciplinary theses server.
Reception of an Award of the Academie des Sciences, Inscriptions et Belles Lettres de Toulouse on December 7, 2008 at the Hotel d'Assezat, Toulouse, for my doctoral thesis dedicated to ancient Egyptian astronomy.
On this December 7, 2008, we were 24 "young" PhD graduates to receive an Award of the Academie des Sciences, Inscriptions et Belles-Lettres de Toulouse. Here is the text pronounced by the President of the Academy: « The Academy Award crowns the work of Miss Karine Gadré on a proposal from Roger Bouigue, Honorary Director of the Astronomical Observatory and University Professor. Miss Gadré designed a book entitled "The conception of a model of star visibility to the naked eye. Application to the identification of the old Egyptian decans." The author of this thesis uses our current knowledge in the field of astronomy for "sorting" the stars used by the Egyptians and preparing all the tables similar to those which came to us in the hieroglyphic form, these tables making genuine "star clocks". From a scientific standpoint, the work of Miss Gadré is a real working basis for better training the future researchers in the field of archaeoastronomy, and secondly, it promotes the development of a closer collaboration between Egyptologists and Astronomers. »
A medal bearing the likeness of Pierre de Fermat and engraved with the name of each winner accompanies the certificate Prize of the Academie des Sciences, Inscriptions et Belles-Lettres de Toulouse.