This work examines the evolution of astronomical thought, as well as the various astronomical and cosmovisional ideas in pharaonic Egypt (c. 2800 -1200 BCE), after the most important religious texts (primarily Pyramid Texts and Coffin Texts, and secondarily Book of the Dead). More specifically, the author examines the astronomical conceptions of the ancient Egyptians concerning the stars, the Sun, the Moon and the Planets, as they are revealed in these funerary texts; a statistical analysis and a global comparative study of the corpora of PT and CT are presented here for the first time. The textual study of the Orphic Hymns and the funerary texts of the Egyptians is conducted within the interdisciplinary framework of both Egyptology and Archæoastronomy. The contents of this volume include: Chapter I, develops the theme and the scope of study, and the methodology, and the tools used to analyze the textual material in our comparative study. Chapter II is intended to be viewed as a concise introduction to the modern concepts of Astronomy, Astrophysics and Cosmology. Chapter III is the nucleus of the study, where conceptions of ancient Egyptians in relation to the celestial bodies -as they are revealed in their funerary texts- are examined. Chapter IV is dedicated to the Hellenic Orphic Hymns, the textual archæoastronomical dating of their astronomical and cosmovisional notions from c. 1300 BCE (an era coinciding with the NK, viz the early Ramesside period), and the study of the astronomical conceptions that the Orphics had about the celestial bodies (stars, Sun, Moon and Planets). Chapter V is a concise comparative study between the ancient Egyptian and the modern astronomical ideas on the celestial bodies. Chapter VI is the focal point of convergence of the main conclusions and ideas of the work, with a review of the conclusions. The work ends with a series of Tables and the Indexes, presenting readers with a review of various modern and ancient astronomical conceptions, as well as with egyptological notions dealt with in the study (classified and categorized in appropriate sections). Written in French with extensive summaries in French, English, Greek and German.