Quick answer: A conjunction is two planets at the same zodiacal degree, 0 degrees apart, so their meanings fuse and act as one voice. Modern astrology counts it among the five major aspects; strict tradition calls it co-presence (synodos), not a ray-aspect. It is neither good nor bad, only as its planets are.
Of all the ways two planets can relate, the conjunction is the closest. It describes not a glance across the chart but a merging, two symbols occupying the same point and speaking together.
What a conjunction actually is
The conjunction is the configuration formed when two planets share the same degree of the zodiac, 0 degrees of separation. Where a sextile, square, trine, or opposition has the planets regarding one another from a distance, the conjunction has them sitting together, so their significations blend into a single fused influence colored by both. Think of it less as two people in conversation and more as two voices singing the same line. This is why it is called the primary configuration: every other aspect is measured out from it. You can place it within the wider family in our guide to aspects explained.
Is the conjunction really a Ptolemaic aspect?
Modern practice lists the conjunction among the five major, or "Ptolemaic," aspects. Strict Hellenistic tradition draws a finer line. Ptolemy's four genuine aspects in the Tetrabiblos, sextile (60 degrees), square (90 degrees), trine (120 degrees), and opposition (180 degrees), are derived from harmonic divisions of the circle and work by planets casting rays at one another. A conjunction casts no ray; the planets are simply together. Tradition therefore calls it co-presence or assembly, from the Greek synodos, and treats it as the strongest connection precisely because the bodies act as one rather than merely looking. Under whole-sign doctrine an aspect is a relationship between whole signs, so a true conjunction means two planets in the same sign. An "out-of-sign" pairing that straddles a boundary, say 29 degrees Aries with 1 degree Taurus, is weak or not a real conjunction at all, even though the degree gap is tiny.
How wide can a conjunction be?
Modern convention uses a single fixed orb, commonly about 8 degrees for planets and 10 degrees for the Sun and Moon. Traditional astrology is more precise. Each planet carries its own orb, and its "moiety" is half of that; the allowable orb between two bodies is the sum of their two moieties, not one flat number. Lilly's whole orbs run roughly Sun 15 degrees, Moon 12 degrees, Jupiter and Saturn about 9 degrees, and Mercury, Venus, and Mars about 7 degrees, though values vary by authority. A conjunction also matters more when it is applying (still forming) than separating (already past). For how conjunctions combine into larger shapes, see chart aspect patterns.
When the Sun is involved: under the beams, combustion, cazimi
When one of the two bodies is the Sun, proximity runs a graded ladder. The Sun's brightness obscures a planet close to it, yet the very center of the Sun does the opposite and dignifies it. Lilly's thresholds give a clear scale.
| Condition | Distance from the Sun | Effect on the planet | |---|---|---| | Cazimi | within ~0 degrees 17 minutes (16 to 17 arcminutes) | greatly strengthened, "seated with the king" | | Combust | within ~8 degrees 30 minutes | severely weakened, significations burnt and obscured | | Under the beams | within ~15 to 17 degrees | obscured and weakened, but not burnt | | Free of the beams | beyond ~17 degrees | normal strength |
Because Mercury never strays more than about 28 degrees from the Sun and Venus never more than about 47 degrees, these two planets are frequently under the beams or combust. Read each condition descriptively: combustion weakens how a planet's function expresses, while cazimi strengthens it. Neither is a fated event. Condition and dignity go hand in hand, a theme we develop in planetary dignities explained.
Neither good nor bad, and always a beginning
A conjunction is intrinsically neither benefic nor malefic. It fuses, and the quality of that fusion is set entirely by the two planets and their condition. Venus with Jupiter tends to blend warmth and expansion into one easy voice; Mars with Saturn fuses drive and restriction into a harder, more disciplined one. The sign they occupy and the health of the whole chart color the result further. This describes structure and tendency, not outcome.
A conjunction is also a seed-point. It marks the start of a synodic cycle between two bodies. The Sun and Moon conjunction is the New Moon, the beginning of the roughly 29.5-day lunar month. The Jupiter and Saturn "great conjunction" seeds a cycle that recurs about every 20 years. Read this way, a conjunction is a starting note, the moment two functions begin a shared story.
Frequently Asked Questions
Is a conjunction a good or bad aspect?
Neither by itself. A conjunction fuses two planets so they act as one, and the flavor of that fusion depends on the planets' natures, their essential dignity and condition, and the sign they share. Benefics such as Venus and Jupiter tend to sweeten it; malefics such as Mars and Saturn tend to harden it.
What orb should I use for a conjunction?
Modern practice commonly uses about 8 degrees for planets and 10 degrees for the luminaries. Traditional astrology instead sums the two planets' moieties (half-orbs), so the allowable gap changes with which bodies are involved. Either way, tighter conjunctions are stronger, and applying ones count for more than separating ones.
What is the difference between combustion and cazimi?
Both describe a planet's nearness to the Sun. Combustion, within about 8 degrees 30 minutes, weakens and obscures a planet's expression. Cazimi, within roughly 16 to 17 arcminutes of the Sun's exact center, does the reverse and greatly strengthens it, as if the planet were seated with the king. Under the beams, within about 15 to 17 degrees, is a milder dimming.
Why do some astrologers say a conjunction is not a real aspect?
In strict Hellenistic tradition, aspects are rays that planets cast across the chart. A conjunction casts no ray because the planets are together, not apart. Tradition calls it co-presence (synodos) and treats it as the strongest connection, yet a distinct category from the four ray-based aspects.
See your own conjunctions
Every chart has its fused pairs. Cast a free birth chart to find yours, explore how they shape you in a personality report, or keep reading on the blog.
