Astrology is the reading of the heavens. The astrologer observes the stars and the wandering lights, sets what they see against tables built up over generations, and casts from them a chart of the influences bearing on a person, a place, or an undertaking. It is the most learned of the divinatory arts and the least immediate — mathematics as much as mystery, and useless in a hurry.
What it reads is tendency over long spans: the cast of a life, the temper of a season, whether an enterprise is begun under influences that favour it. It will not say what waits around the next corner, and an astrologer asked for that will say so. Its most characteristic work is the natal chart, since the sign a character was born under is a standing Birthsign carried for life, and reading such a sign — a stranger’s, or a newborn’s — is exactly what this art is for.
Invoking it. A divination is a Success Test like any other Mystical Ability, but the success level buys the quality of the reading rather than an effect on the world: nothing on a Marginal Failure, a true but partial answer on a Marginal Success, a clear one on a Critical Success — and on a Critical Failure a false reading the astrologer has no inkling is false, delivered with all the confidence of a true one.
What bears on the test. A clear sky, the instruments, and the tables; for a natal chart, the subject’s exact hour and place of birth. Working from an estimate, or under broken cloud, is a penalty the gamemaster sets, and is the usual cause of a confidently wrong horoscope. A full night, good instruments, and an exact hour are not a penalty. No divination answers under Aural Shock, none may be fated, and a question already asked of this art returns its first answer again until circumstances materially change.
The art, and the reading of its results, are set out under Astrology and Divination.