Aspects
Aspects between planets
An aspect shows how two chart points are positioned in relation to each other. A reading uses it as an image of how easily or tensely two themes may combine.
Brief explanations help you read without specialist knowledge. Astrological terms describe a symbolic method, not scientifically established personality traits.
An aspect is simply the angular separation between two points in a chart — usually two planets, but sometimes a planet and the Ascendant or Midheaven — measured along the ecliptic. Given two ecliptic longitudes, the separation is elementary spherical geometry: subtract one from the other and reduce the result to the 0-180 degree range. Traditional astrology names a small set of these separations as "major aspects" because they divide the 360-degree circle by small whole numbers: conjunction (0 degrees, the same point), opposition (180 degrees, half the circle), trine (120 degrees, a third), square (90 degrees, a quarter), and sextile (60 degrees, a sixth). Each is allowed a small tolerance around the exact angle, called an orb, before it stops counting as that aspect.
The measurement itself is exact and reproducible — the same two birth-data points always yield the same separation, calculable from the same ephemeris this project uses for every other placement. What is traditional, not measured, is the claim that a given aspect type carries a particular quality (a trine as "easy," a square as "tense," and so on) — this is a long-standing interpretive convention describing how two placements are said to interact, not a further physical quantity.
Aspects are one of several ways placements relate to each other; see "Planets in the natal chart" for what is being related, and "Astrological houses" for where each end of the aspect is said to apply.
The measurement itself is exact and reproducible — the same two birth-data points always yield the same separation, calculable from the same ephemeris this project uses for every other placement. What is traditional, not measured, is the claim that a given aspect type carries a particular quality (a trine as "easy," a square as "tense," and so on) — this is a long-standing interpretive convention describing how two placements are said to interact, not a further physical quantity.
Aspects are one of several ways placements relate to each other; see "Planets in the natal chart" for what is being related, and "Astrological houses" for where each end of the aspect is said to apply.