An astrologer practices one or more forms of astrology
Astrology consists of a number of belief systems which hold that there is a relationship between astronomical phenomena and events in the human world...

. Typically an astrologer draws a horoscope
In astrology, a horoscope is a chart or diagram representing the positions of the Sun, Moon, planets, the astrological aspects, and sensitive angles at the time of an event, such as the moment of a person's birth. The word horoscope is derived from Greek words meaning "a look at the hours" In...

 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
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 observation or manual calculation of celestial phenomena.