The traditional major aspects are sometimes called Ptolemaic aspects since they were defined and used by Ptolemy in the 1st Century, AD. The orbs are subject to variation, depending on the need for detail and personal preferences. The conjunction aspect (essentially 0°, discounting orb) can be in either category, depending on which two planets it is that are conjunct.Ī list of aspects below presents their angular values and a recommended orb for each aspect. But even in modern times, aspects are considered either hard (the 90° square, the 180° opposition) or easy (the 120° trine, the 60° sextile). The more modern approach to astrological aspects is exemplified by research on astrological harmonic, of which John Addey was a major proponent, and which Johannes Kepler earlier advocated in his book Harmonice Mundi in 1619. Modern usage places less emphasis on these fatalistic distinctions. In medieval astrology, certain aspects, like certain planets, were considered to be either favorable ( benefic) or unfavorable ( malefic). The more exact an aspect, the stronger or more dominant it is said to be in shaping character or manifesting change. According to astrological tradition, they indicate the timing of transitions and developmental changes in the lives of people and affairs relative to the Earth.Īs an example, if an astrologer creates a horoscope that shows the apparent positions of the celestial bodies at the time of a person's birth (a natal chart), and the angular distance between Mars and Venus is 92° ecliptic longitude, the chart is said to have the aspect "Venus square Mars" with an orb of 2° (i.e., it is 2° away from being an exact square a square being a 90° aspect). Aspects are measured by the angular distance in degrees and minutes of ecliptic longitude between two points, as viewed from Earth. In astrology, an aspect is an angle the planets make to each other in the horoscope, also to the ascendant, midheaven, descendant, lower midheaven, and other points of astrological interest.
The astrological aspects are noted in the central circle of this natal chart, where the different colors and symbols distinguish between the different aspects, such as the square (red) or trine (green)