An astrologer is someone who believes that the positions of celestial bodies like planets, stars and moons have influence over events on Earth. They use a birth chart to determine a person’s Sun sign, Moon sign and rising sign. They may also consider the position of Chiron (a comet-like body), Vesta, Ceres, and Juno or the asteroid Pallas as well as the North and South Nodes — mathematical points on the chart that act as karmic north star and southern cross, respectively. Many astrologers also read synastry charts, which compare a person’s birth chart to a friend or love interest to see how their energies might clash, connect or support one another.
Astrology can be considered a form of divination and was widely practised in ancient Egypt, Rome, the medieval world and early modern Europe. It was popularized by astronomers including Tycho Brahe, Johannes Kepler and Galileo, who believed it to be an accurate science. In its most rigorous form, it postulated a completely mechanistic universe that denied both deity and man the possibility of intervention, and was thus vigorously attacked by orthodox Christianity and Islam.
It was not until the late 1600s that Isaac Newton paved the way for modern astronomy, demonstrating that the laws that make an apple fall from a tree also apply to celestial bodies. Since then, astrology has become a separate discipline that relies on the scientific method for its predictions. But if you’re curious about astrology, Sky & Telescope Senior Editor Alan MacRobert offers some key building blocks to kickstart your understanding of the language of the stars.