Осирис and other gods
Astronomical opening also played an important role and in ancient Egyptian religion. Was considered that the constellation of Orion was represented by Osiris - god of death and revival. The Milky Way - goddess Nut. It named "the huge mother of stars who are giving rise to gods" because it was mother Ra, god of the sun. The astronomy played large role in religion of Egyptians.
Though ancient Egyptians did not know all about astronomy, they had a good representation about the sky. They could use knowledge to define time. Stars always were a source of interest at people, and ancient Egyptians were not an exception.
Time definition on stars
The astronomy in ancient Egypt was in the best way to learn time at night. Each group of stars is closed in forty minutes every night. Supervision over position of group of stars depending on day of year will tell to the person what now time. Ancient Egyptians stored astronomical tables which helped them to trace, what groups of stars to use to define time. In columns of these tables year of time with intervals in ten days is covered. All it is written down in ascending order. Ancient Egyptians esteemed astronomy rather организованно.
Astronomy use allowed them to trace year.
The Drevneegipetsky astronomy was used in a calendar to define, when it is necessary to add the thirteenth month. In a calendar it was used thirteen months as twelve lunar months were not enough for the whole year. Therefore, when the constellation of Sirius is closed, at the very end of the twelfth month the thirteenth began. It has allowed to use ancient Egyptians astronomy for exact tracing of current years. Later, they have transferred superfluous month to the general year having made thirty days in a month and five holidays in the end. After formation of this calendar the binding to stars has not been made. Soon such calendar became inexact and has ceased to correspond to seasons.