Astrology is the study of the influence that distant cosmic objects, usually stars and planets, have on human lives. The position of the sun, stars, moon and planets at the time of people's birth (not their conception) is said to shape their personality, affect their romantic relationships and predict their economic fortunes, among other divinations.
To produce a more accurate reading, astrologers check to see what sign each planet was in at the time of birth. The planets and signs combine with other elements, such as houses and angles, to form a complex and often very specific profile of a subject's personality, life and future prospects.
In the West, astrology most often consists of a system of horoscopes purporting to explain aspects of a person's personality and predict future events in their life based on the positions of the sun, moon, and other celestial objects at the time of their birth. It is divided as:
Mundane Astrology - This is used to examine world events and make predictions about national affairs, wars and economies.
Interrogatory Astrology - This branch can be further subdivided, but generally refers to astrology that seeks to make specific predictions or analyses about the subject's objectives or events within the subject's life.
Natal Astrology - This is what most people think of when they think of astrology. Natal Astrology seeks to make predictions and analyses based on the date of a person's birth. It's based on the idea that everything that happens to something is expressed at the very beginning of that thing, sometimes known as the Law of Beginnings.