A lesser known aspect of astrology is the use of asteroids. The asteroid belt between Mars and Jupiter has many thousands of course, but some of the bigger ones (from 250km – 1000km in diameter) have been named and given symbolic archetypal meaning by modern astrologers.
Four primary ones are Ceres, Vesta, Juno and Pallas, discovered just over a hundred years ago, although it is only this year (2015) that we get our first close-up photos of Ceres from NASA’s Dawn. spacecraft. Note the recurring theme of Roman goddesses in the names of these asteroids.
Why bother using such small asteroids in a horoscope interpretation, you might ask. Well Vesta alone is 10% of the mass of the entire asteroid belt, so they do pull their weight. Also the complex astrophysical parameters, as well as the discovery date of a planet or asteroid also contribute to the astrological symbolism thereof. For example Mars – a red planet – is traditionally associated with the god of war.
Other well known asteroids in use might be Chiron and Lillith, and there are a few dozen other lesser known ones. Modern astrologers simply use the positions of the asteroids to fine tune any themes in a horoscope. Besides the asteroid belt, there are also Trans-Neptunian asteroids, and then what are known as the Centaurs, of which Chiron is best known. You can find the current astrological positions of the asteroids at Serennu.