Astronomy is a science that studies everything outside of the earth's atmosphere, such as planets, stars, asteroids, galaxies; and the properties and relationships of those celestial bodies. Astronomers base their studies on research and observation. Astrology, on the other hand, is the belief that the positioning of the stars and planets affect the way events occur on earth. If you're interested in the solar system and the planets, other celestial objects like asteroids and comets, other galaxies and the rest of the universe, what makes up space, and the possibility of alien life or space travel, astronomy is the field you're considering.