Quincunx (Inconjunct) Aspect: The 150° Angle in a Birth Chart

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A quincunx is a contact between two planets that sit 150° apart in the zodiac: five signs, the gap between a trine (120°) and an opposition (180°). It is also called the inconjunct. This guide explains the geometry, why astrologers usually read it as a contact that asks for adjustment rather than as harmony or open conflict, how to check for one yourself, and how it differs from its 30° neighbour, the semi-sextile.

Educational concept, not a chart feature. The quincunx is one of the minor aspects, and the free birth chart does not calculate, list, flag or draw quincunxes: its wheel shows only the five major aspects. If two quincunxes in your chart happen to form a yod, the wheel may still draw the yod's base sextile, because the sextile is one of those five, but it never draws the two 150° legs and never names a yod. The figures on this page were worked out offline, by hand or with the same routines behind the free chart; they are not a hidden feature. Ask the Astrologist can talk about the quincunx as an idea, or about a 150° contact you have measured yourself, but it is not given your planets' degrees and does not detect minor aspects.

The geometry: 150°, five signs apart

The zodiac is a circle of 360°. Two planets 150° apart cover five-twelfths of it, which is where the Latin name comes from: quincunx means five twelfths. Counted by sign, a quincunx usually joins a sign to the one five signs further on, in either direction: Aries to Virgo, Taurus to Libra, Gemini to Capricorn.

Among the five major aspects, the nearest angles are the trine at 120° and the opposition at 180° (see major aspects). The quincunx sits between them and belongs to neither family. That is the first reason it is treated separately: the free chart's 8° orb for the trine and opposition stops at 128° and 172°, so a 150° pair is not picked up by any major aspect at all.

Why it is read as an adjustment contact

When two planets sit in signs exactly five apart, those signs normally share no element, no modality and no polarity:

• Aries and Virgo: fire and earth, cardinal and mutable, one positive (active) sign and one negative (receptive) sign.
• Taurus and Libra: earth and air, fixed and cardinal, receptive and active.
• Gemini and Capricorn: air and earth, mutable and cardinal, active and receptive.

Element, modality and polarity are the three ways signs usually "share a language" (see element balance and modality balance). Because sign-to-sign quincunxes normally share none of them, astrologers commonly describe the two planets as working from different assumptions. The usual reading is that neither planet easily supports the other and neither confronts the other head-on, so the contact tends to show as an ongoing need to adjust, reorganise or make room for both. That is a teaching explanation, not a law, and it describes tendencies, not outcomes.

Historical background: aversion. In older whole-sign astrology, aspects were counted between signs, and only certain sign relationships counted as "seeing" one another. Signs five apart, like neighbouring signs, were said to be in aversion: they did not behold each other by any of the Ptolemaic aspects. That is background for why the 150° relationship was long left out of the main aspect list. It is not proof that the modern quincunx reading is the same as an ancient doctrine; the modern idea of a 150° aspect with its own meaning developed later.

Terminology: quincunx, inconjunct and semi-sextile

Many astrologers use quincunx and inconjunct as synonyms for the 150° contact, and that is how these pages use them.

The semi-sextile is the 30° contact between neighbouring signs, such as Aries and Taurus. Like the quincunx it is a minor aspect, and like the quincunx it is not calculated by the standard chart. On Astrologist.com, quincunx and inconjunct mean the 150° contact and semi-sextile means the 30° one. Usage has varied over time, and some writers have also used "inconjunct" more loosely for both, so check how a source defines the word before comparing readings.

Orbs: this guide's 3° working band

Every aspect needs a tolerance: how far from exact 150° a pair may be and still be counted. For the quincunx there is no single rule. Published conventions differ: the Astrodienst Astrowiki article on the quincunx describes it as valid with an orb of up to three degrees, while Nicholas Campion's table of aspects on Skyscript gives it 2°.

This guide's working band is within 3° of exact 150°, measured in zodiacal (ecliptic) longitude. It was chosen so that the examples and hand checks on these pages can be reproduced. It is an educational convention for these guides, not a calculator rule and not a claim about what every astrologer does. The site's major-aspect orbs, 8° for most aspects and 6° for the sextile, are not reused for the quincunx; aspect orbs explains where those figures apply.

Measuring it: degrees, not signs

A quincunx in these guides is measured by degree:

1. Write each planet as a longitude from 0° Aries: add the start of its sign (Aries 0, Taurus 30, Gemini 60, Cancer 90, Leo 120, Virgo 150, Libra 180, Scorpio 210, Sagittarius 240, Capricorn 270, Aquarius 300, Pisces 330) to its degree, with minutes divided by 60.
2. Take the shortest separation: separation = min(|a − b|, 360 − |a − b|).
3. Distance from exact: |separation − 150|. If that is 3 or less, the pair is inside this guide's band.

Only zodiac longitude is used. There is no applying or separating rule here, and declination, latitude and house-space measurements are left out.

Out-of-sign quincunxes. Because the test is by degree, a pair can be inside the band without sitting in signs five apart. A planet at 29° Aries (29°) and one at 1° Sagittarius (241°) are 148° apart, 2° from exact, so they count as a quincunx under this band, yet Aries and Sagittarius are both fire signs and both active. The "no shared element, modality or polarity" explanation above therefore does not apply to every degree-based quincunx; it describes the usual sign-to-sign case. Out-of-sign aspects covers the same degree-versus-sign issue for the major aspects.

Birth time. The Moon moves about 12° to 15° a day, so a quincunx involving the Moon cannot be claimed from a chart without a reliable birth time; it needs a check across the whole possible birth window, or it stays unestablished. The internal noon placeholder used for unknown times is not your birth moment. Faster planets such as Mercury, Venus, the Sun and Mars move less, but a pair sitting close to the 3° line can still cross it within a day, so an unknown time makes those borderline cases time-sensitive too.

Worked example: Ruben

Ruben is the fictional chart used across several Astrologist.com guides: London, 5 January 1993, 12:00 (12:00 UT). His positions were recalculated for this page with the production chart routines and rounded to 0.01°.

No other pair among the Sun to Pluto falls within 3° of 150° in his chart.

What the example shows:

• Neither contact appears on the free chart. Neither pair is within any major-aspect orb, so the wheel draws no line between them and the aspect list does not mention them.
• Both are sign-to-sign quincunxes. Gemini and Capricorn share no element, modality or polarity, and neither do Cancer and Aquarius, so the usual explanation fits both.
• No yod. The two quincunxes share no planet, so there is no single body quincunx to two others, and no sextile base joins them. A yod needs both; see yod in astrology.
• The Moon pair depends on the time. Recalculated across the whole London date, the Moon-Mercury separation runs from about 145.4° at 00:00 to about 157.3° at 23:59, and it is inside the 3° band only from roughly 03:20 to 15:20. Ruben's time is stated, so his chart can use it; the same date without a time could not. The Mars-Saturn pair stays between about 151.5° and 152.1° all day.

How the quincunx fits with other topics

Minor aspects gives the general picture of the smaller angles. When you count a chart's aspects, the quincunx is not included: how many aspects a birth chart has counts the five major aspects only. In the same way, a planet whose only contacts are quincunxes is still unaspected under the five-aspect test these guides use; unaspected or not: borderline cases explains why some astrologers would see it differently.

Some astrologers also apply minor aspects to calculated points such as the lunar Nodes and Chiron; that is outside this page's method, which uses the planets from the Sun to Pluto only.

For what each planet tends to bring to a quincunx, see quincunx aspects by planet; for the pattern made of two quincunxes and a sextile, see yod in astrology. Planet meanings covers the planets themselves, the methodology page explains what the free chart calculates, and the Aspects library lists the other guides.

Related articles

• Yod in Astrology: Two Quincunxes and a Sextile
• Quincunx Aspects by Planet
• Minor Aspects in Astrology
• Aspect Orbs in Astrology
• Out-of-Sign Aspects
• Astrology Aspects Overview

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