|Ancient Egyptian Astronomy|
However, the Egyptians back then did not know about the extra one quarter of a day the earth takes to rotate around the Sun. Thus, the calendar fell back by one day after every four years. Nevertheless, it remains an important invention which is relevant even in today’s world.
Astronomical observations of the stars determined the annual flooding of the river Nile. The Egyptian pyramids were all made to align with the pole star, using astronomical knowledge. In fact, most of the buildings during the period of Egypt were made to align with some important star or the other. Thus orientations of the structures varied from place to place, depending on the primary celestial object of that place.
Astronomy was literally worshipped by the ancient Egyptians. Some of the gods and the goddesses they worshipped where borne out the observations of various constellations or planetary bodies. The sun alone had several forms in their faith, depending on its various positions during a day. A discussion on Egyptian astronomy is incomplete without the mention of Ptolemy, one of the most famous astrologers of the Roman Egypt period, whose book, “Almagest” is considered as one of the most influential of its kind in the astrological history of the West.
Info Source: http://www.greaterlearning.org/astronomy/Egyptian-Astronomy.html