Most of our understanding of Egyptian astrology is contained within the Cairo Calendar, which consists of a listing of all the days of an Egyptian year. The listings within the calendar all take the same form and can be broken up into three parts: I, the type of day (favorable, unfavorable etc), II, a mythological event which may make a particular day more favorable or unfavorable, III, and a prescribed behavior associated with that day. Unlike modern astrology as found within newspapers, where one can choose whether to follow the advice there in or not, the Egyptians strictly adhered to what an astrologer would advise. As is evidenced by the papyrus of the Cairo Calendar, on days where there were adverse or favorable conditions, if the astrologers told a person not to go outside, not to bathe, or to eat fish on a particular day, such advice was taken very literally and seriously.
Some of the most interesting and misunderstood information about the Ancient Egyptians concerns their calendarical and astrological system. Of the greatest fallacy about Ancient Egypt and it's belief in astrology concerns the supposed worship of animals. The Egyptians did not worship animals, rather the Egyptians according to an animals astrological significance, behaved in certain ritualistic ways toward certain animals on certain days. For example, as is evidenced by the papyrus Cairo Calendar, during the season of Emergence, it was the advisement of the Seers (within the priestly caste), and the omens of certain animals they saw, which devised whether a specific date would be favorable or unfavorable.
The basis for deciding whether a date was favorable or unfavorable was based upon a belief in possession of good or evil spirits, and upon a mythological ascription to the gods. Simply, an animal was not ritually revered because it was an animal, but rather because it had the ability to become possessed, and therefore could cause harm or help to any individual near them. It was also conceived of that certain gods could on specific days take the form of specific animals. Hence on certain days, it was more likely for a specific type of animal to become possessed by a spirit or god than on other days. The rituals that the Egyptians partook of to keep away evil spirits from possessing an animal consisted of sacrifice to magic, however, it was the seers and the astrologers who guided many of the Egyptians and their daily routines. Hence, the origin of Egyptians worshipping animals, has more to do with the rituals to displace evil spirits, and their astrological system, more so than it does to actually worshipping animals.