Western astrology studies the influence of heavenly bodies (the sun, moon, stars and planets) on the earth and on human beings. To study their influence, one of the things used are the star groups in the zodiac. The zodiac is the part of the sky through which the orbits of the sun, moon and planets run.
Differences between exoteric and esoteric astrology
There are different kinds of interpretations and levels to be studied in western astrology. Broadly speaking, there is the more common exoteric astrology (known to the general public as astrology) and esoteric astrology (better known as esotericism). You'll find more information about esotericism under the heading 'What is esotericism?'.
The most common form of astrology is exoteric astrology. Exotericism deals with everything you experience from the outside. Time and space play an important part in our lives. The same goes for this type of astrology. The position of the planets at a specific time are compared to the position of the planets at the time of someone's birth. On the basis of the position of the planets and someone's constellation an impression is made of someone's personality and it becomes clear by which energies someone is governed.