Biquintile: the 144° minor aspect in a birth chart

A biquintile is an aspect between two planets that stand 144° apart along the ecliptic. The angle equals two quintiles, two fifths of the circle, hence the name. The biquintile is a minor aspect and, together with the quintile, makes up the fifth harmonic: the series of angles that comes from dividing the circle into five.

Geometry: two fifths of the circle

Place five points evenly around a circle, and neighbouring points are linked by a quintile (72°), while points one apart are linked by a biquintile (144°). This shows that the biquintile is not a weaker or stronger version of the quintile but the other side of the same division. Astrologers read both angles in the same key.

An angle of 144° equals four signs plus 24°. The biquintile is not tied to a pair of signs: a planet at 6° Aries is in biquintile to one at 0° Virgo, and a planet at 20° Taurus to one at 14° Libra. Elements and modalities can be anything.

Biquintile and quincunx

The biquintile is easy to confuse with the quincunx: 144° and 150° differ by only 6°. With orbs of 2-3° their zones do not overlap, but planets about 147° apart belong to neither. So in an aspect table it pays to look at the exact angle, not just the name.

The two aspects differ in nature. The quincunx comes from dividing the circle into twelve and links signs that share nothing; the biquintile comes from dividing it into five and is not tied to signs at all. The quincunx is usually read as an aspect of constant adjustment, the biquintile as an aspect of particular ability.

Where the aspect comes from

The biquintile, like the quintile, was proposed by Johannes Kepler in the early 17th century. For Kepler aspects had a geometric basis: an angle counted if it came from a regular polygon that can be built with compass and straightedge. The pentagon is such a polygon, so 72° and 144° gained the same standing for him as the classic 60°, 90° and 120°.

In the 20th century the fifth harmonic became a subject of research for John Addey, author of Harmonics in Astrology (1976). He linked it with form, style and the capacity to make things. That line of thought gave the quintile and biquintile their reputation as aspects of talent.

The orb of a biquintile

The biquintile gets a narrow orb: 1-2°, up to 2-3° with the Sun or Moon. Because the quincunx is so close, a margin wider than 2° is especially risky: the aspects begin to overlap, and the same angle would have to be read two ways. Most astrologers ignore a biquintile wider than 2°.

How to read a biquintile

The biquintile is described much like the quintile: two functions combine into a recognisable signature, and the person does something in their own way. Some writers see a difference in shade. The quintile, in their account, is closer to a talent that shows itself, the biquintile to an ability a person notices later and develops deliberately. This is an interpretation, not a rule, and the literature phrases it in different ways.

The order of reading is the usual one:

• Planets. Which functions are combined. A biquintile of Jupiter to Pluto is read through scale and influence, one of Mars to Saturn through disciplined action.
• Signs. How each planet acts, read in its own sign.
• Exactness. A biquintile within 1° is worth noting.

The biquintile refines the picture and rarely changes the overall reading of a chart, but it can explain a link between two planets that share no major aspect.

Example: the biquintile in Barack Obama's chart

In Barack Obama's chart Jupiter is at 0°51′ Aquarius and Pluto at 6°58′ Virgo. The angle between them is 143°53′, an orb of 0°07′. Jupiter and Pluto share no major aspect in this chart, and the biquintile is their only link within the usual orbs.

Tradition would describe a combination of Jupiter, the planet of growth and belief, with Pluto, the planet of power and deep change, as the capacity to see large processes and influence them. This describes a link between functions of the chart, not a judgement of the person.

The biquintile in synastry and transits

In synastry biquintiles between two charts are rarely counted, and with an orb of no more than 1°: inter-chart aspects are numerous, and minor ones easily get lost. An exact biquintile between the partners' personal planets is read as a shared interest or skill that both develop together.

The biquintile is hardly used in transits, for the same reason as the quintile: the fifth harmonic describes the quality of how functions combine, not a period or an event. The exception is astrologers who work with harmonics systematically.

How to find a biquintile in your own chart

Not all software shows minor aspects, so a biquintile is often found by hand. Convert the planets' positions to absolute degrees: Aries 0-30°, Taurus 30-60°, Gemini 60-90° and so on to Pisces at 330-360°. Obama's Jupiter at 0°51′ Aquarius becomes 300°51′, his Pluto at 6°58′ Virgo becomes 156°58′.

Subtract the smaller number from the larger: here that gives 143°53′. If the result is over 180°, subtract it from 360°. An angle within 1-2° of 144° is a biquintile. Take care at this point: an angle of 147-148° belongs to neither the biquintile nor the quincunx, while 149-151° is already a quincunx. The two planets' degrees within their signs differ by 24° one way or the other, and the signs are three or four apart, depending on the degrees.

Biquintiles in configurations

The best-known figure of the fifth harmonic, called the golden yod, is made of a quintile and two biquintiles: two planets in quintile and a third in biquintile to both, since 72 + 144 + 144 = 360. In shape it resembles the yod, but its base is wider: a 72° quintile instead of a 60° sextile. With tight orbs such a figure is rare in practice. The classic configurations of major aspects are covered under aspect patterns.

In celebrity charts

The tightest examples among the published charts.

• Dua Lipa: Venus biquintile Neptune, orb 0°01′
• JD Vance: Sun biquintile Jupiter, orb 0°05′
• Jannik Sinner: Venus biquintile Uranus, orb 0°05′

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