Astrology is a discipline that studies the positions of celestial bodies in relation to events on Earth. An astrologer interprets these relationships to make predictions about future events.
A horoscope is an astrological chart that lists the position of the sun, moon and planets at the time of your birth. It also outlines the houses that these bodies “reside” in, and the aspects (aspects are the ways the planets interact with each other). An expert astrologer will be able to tell you what sign your ascendant is, the house your sun is in, the nature of your conjunctions with Venus, Mars, Jupiter, and Pluto. They may even know about Chiron, the dwarf planet Ceres, and asteroids like Pallas, Vesta, and Juno.
In the past, astrologers believed that there were special relations between certain celestial bodies and particular events on Earth. In its most rigorous aspect, astrology postulated a mechanistic universe and denied the possibility of divine intervention or man’s free will; as such, it was vigorously attacked by orthodox Christianity and Islam.
But astronomy is a completely different field, and focuses on everything outside the Earth’s atmosphere – planets, stars, asteroids, galaxies. Astronomy studies these things by using the scientific method. It’s possible for both astrologers and astrophysicists to work together on projects, but the two disciplines are not the same. Astrology is a form of divination; it’s not a science.