Astrologer

An astrologer practices one or more forms of astrology. Typically an astrologer draws a horoscope for the time of an event, such as a person's birth, and interprets celestial points and their placements at the time of the event to better understand someone, determine the auspiciousness of an undertaking's beginning, etc. However, the methods employed by astrologers are variable and depend on the particular astrological tradition they employ and the information desired.

In the far past, the role often entailed astronomical observation or manual calculation of celestial phenomena. In more modern times, however, these methods have largely been replaced by pre-calculated ephemerides and astrological software. Astrologers are sometimes known as astrologists. Historically the term mathematicus was used to denote a person proficient in astrology, astronomy, and mathematics.

The first organized system of astrology was developed in Mesopotamia in the second millennium BCE. The Babylonians' system of omen astrology was relatively simple and direct compared to later developments, foretelling mundane occurrences such as famine, war, peace, and so on based on predefined celestial indicators. Babylonian astrologers provided a service for those in power, advising them in their decision-making.

At this time astrology and astronomy were not distinguished as separate disciplines; the act of astronomical observation was often done by someone who had astrological motives for doing so. Indeed, astrologers' professional responsibility and desire for predictive knowledge for a large part spurred the advancement of astronomy, and the Babylonians developed a very precise ability to mathematically predict the location of celestial points and phenomena based upon their observable cycles.