Ancient Egyptian astronomy was mostly concerned with practical time reckoning. It consisted mainly of schematic arrangements for the division of the night using decan stars. Egyptian observations were made with the naked eye assisted by a few simple instruments. The ancient Egyptians did not apply complex mathematics to their astronomy.
Most of the surviving documentary evidence for Egyptian astronomy is found on funerary monuments. There are no records of any actual astronomical observations (or mathematical models or precise predictive tables) among the immense mass of documents from Egypt. The lack or records of actual astronomical observations is a puzzle. Late Egyptian astronomical texts are Greek in origin. There are no technical records or writings dealing with Egyptian astronomy until the 1st-millennium BCE, after Egypt's conquest by Persia. Prior to this time the Egyptians used simple astronomical methods to measure time and to develop accurate calendars, as well as to directionally align their buildings. Egyptian astronomy began to flourish after Egypt was conquered by Alexander the Great (in the 4th-century BCE). Many of the late Egyptian astronomers, were in fact, of Greek heritage and Egyptian astronomy during this period was, in actuality, Hellenistic in character.