In financial astrology, the angles formed between two planets as viewed from the Earth have either bullish or bearish implications for the market. In astrological jargon, these angles are called aspects. The angles are measured from a line drawn from the Earth to the sun. When a planet is positioned so that the Earth is directly between it and the sun, it is said to be in geocentric opposition, or at 180 degrees. Similarly, if the planet is at 90 degrees to the Earth-sun line, the planets are said to be square.
Squares are supposedly bearish.
Conjunctions and oppositions are supposedly positive. But this interpretation is not universally accepted. David Williams, author of Financial Astrology, uses an aspect-scoring system in which he attributes bullish or bearish influences to each aspect according to which two planets are involved. For example, he considers the conjunction of Mercury and Earth positive, but that of Mars and Earth negative. Even with this difficulty, however, financial astrologers have used aspect rule-based systems to predict stock movements with enough success that they are still widely followed.