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Aspects: how the planets "talk" to each other

Conjunction, opposition, trine, square, sextile: the five major aspects of astrology. How to read the angles between planets and the orb.

9 min read · Updated 2026-06-11

By now you know the planets (who), the signs (how) and the houses (where). One piece is still missing: the dynamic dimension, how all these elements interact. That is the job of aspects.

An aspect is simply a geometric angle between two planets, measured along the ecliptic. Some angles count as significant in astrology; the rest are ignored. Aspects are the grammar of the chart. Without them you have a static list of placements. With them you have a system that interacts, builds tensions, smooth flows, and challenges.

The basic logic

Picture two planets, say Mars and Saturn, at a given moment. You can measure the angle that separates them on the zodiac:

• If Mars is at 10° Aries and Saturn at 10° Libra, the gap is 180°, an opposition.
• If Mars is at 10° Aries and Saturn at 10° Cancer, the gap is 90°, a square.
• If Mars is at 10° Aries and Saturn at 10° Leo, the gap is 120°, a trine.
• And so on.

The "notable" angles, the ones that count as aspects, are those that are whole-number divisions of the circle:

• 360 ÷ 1 = 360° (equivalent to 0°) → conjunction
• 360 ÷ 2 = 180° → opposition
• 360 ÷ 3 = 120° → trine
• 360 ÷ 4 = 90° → square
• 360 ÷ 6 = 60° → sextile

These five are the major aspects, shared by every school of astrology. They are the common ground.

There are also minor aspects (semi-sextile at 30°, quintile at 72°, sesquiquadrate at 135°, and others) that some astrologers use and others do not. This guide sticks to the five majors.

The conjunction (0°): fusion

• Angle: 0° (both planets in the same place)
• Symbol: ☌
• Tone: addition, fusion, intensification

When two planets are conjunct, their energies blend and add up. A Sun-Mercury conjunction means identity fused with thought (a mind that structures the self). A Venus-Mars conjunction means desire and love glued together (immediate passion). A Saturn-Pluto conjunction means structure and forced transformation (often a difficult historical period, like 2020).

The conjunction is neither "good" nor "bad" in itself: it takes on the colour of the two planets involved. A Sun-Jupiter conjunction runs warm and expansive; a Mars-Saturn conjunction runs frustrated and constrained.

It is the most powerful aspect. A tight conjunction (orb under 2°) often dominates a chart.

The opposition (180°): polarity tension

• Angle: 180° (planets diametrically opposed)
• Symbol: ☍
• Tone: tension, polarity, mirroring

An opposition sets two planets face to face. They sit in opposite signs (Aries vs Libra, Taurus vs Scorpio, and so on), which are complementary polarities by design.

The opposition creates a dynamic tension: you struggle to hold both energies at once, since they pull in opposite directions. It is also a fertile tension, though, because it forces you to swing between the two poles and eventually bring them together.

It often shows up in your relationship to other people: you project one of the two planets onto those around you and live out the other yourself. The psychological work is to re-integrate both within you.

The trine (120°): harmony

• Angle: 120° (planets in signs of the same element)
• Symbol: △
• Tone: ease, talent, flow, harmony

A trine puts two planets in signs of the same element (two fire signs, two air, two water, or two earth). Their energies flow smoothly.

The trine is usually seen as beneficial. It points to innate gifts, easy abilities, things that come to you naturally. That is also its trap: a trine can lull you to sleep, because it sets no challenge. A nice trine can leave you resting on your laurels.

A Sun-Moon trine means harmony between the conscious and the unconscious, a kind of psychic balance. A Venus-Jupiter trine means luck in love and pleasure, an easy charm.

The square (90°): friction

• Angle: 90° (planets in signs of the same mode but incompatible elements)
• Symbol: □
• Tone: tension, challenge, friction, blockage

A square puts two planets in incompatible signs (Aries-Cancer, Taurus-Leo, Gemini-Virgo, and so on). The energies get in each other's way.

The square is usually seen as difficult. It marks recurring points of tension, things that do not fall into place on their own. But it is also an engine: squares are the aspects that make you move, because they create a discomfort that demands resolution.

Key idea. Modern astrology tends to de-pathologise squares. A chart with no square can look "easy" but often lacks drive. The great lives are frequently built on well-handled squares.

A Sun-Saturn square means a recurring sense of being blocked by authority or by time, but also a self-discipline forged through friction. A Mars-Pluto square means explosive intensity, clashes with power, and a capacity for radical transformation.

The sextile (60°): opportunity

• Angle: 60° (planets in signs of compatible elements)
• Symbol: ✶
• Tone: opportunity, cooperation, easy dialogue

A sextile links two planets in compatible signs (water-earth, or fire-air). Think of it as a lighter, more active trine.

The sextile is beneficial but asks for a minimal effort: opportunities present themselves, but you have to seize them. Unlike the trine, which works on its own, the sextile needs a small step in your direction.

A Mercury-Jupiter sextile means openings for communication and teaching, a mind that broadens. A Venus-Saturn sextile means lasting romantic commitments, the kind that build slowly.

The orb: the margin of tolerance

No aspect is ever "exact to the arcsecond." Mars might be at 89.5° from Saturn. Is that a square or not? Yes, within the limit of the orb.

The orb is the margin of tolerance around the exact angle within which the aspect still "counts." The closer an aspect sits to the exact angle, the more it is felt.

Standard orbs (they vary a little by school):

Astrologers often grant more orb to the Sun and the Moon (up to 10-12°) because they carry more weight. And they grant less orb to slow planets in aspect to one another, unless a personal planet is involved.

An aspect with an orb under 2° counts as very tight and especially active. An aspect with an orb between 2° and 5° is moderate. An aspect with an orb above 5° is light, sometimes treated as negligible.

Applying vs separating aspects

When two planets are moving toward an exact aspect, the aspect is applying ("coming into" the aspect). When they drift apart after forming it, the aspect is separating ("moving out of" the aspect).

• Applying: the faster planet is closing in on the slower one. The aspect "climbs" in intensity and runs stronger. It is often tied to an event ahead or to a tension building up.
• Separating: the faster planet is pulling away. The aspect "fades" and is felt less. It points to a past event or to a tension easing off.

This distinction matters most for horary astrology (asking a question about a future event) and for predictive astrology (transits, progressions). For reading a natal chart, you note the orb and whether it is applying or separating, but it stays a technical detail.

Notable configurations

Beyond aspects between two planets, there are configurations that involve several planets at once. A few classics:

• Stellium: 3 or more planets conjunct in one sign or house. A major concentration of energy in that zone.
• Grand Trine: three planets forming an equilateral triangle (3 trines of 120°). Often in the same element. A configuration of strong talent, sometimes a bit too comfortable.
• Grand Cross: four planets forming a square (4 squares of 90° plus 2 oppositions). A configuration of maximum tension, a powerful and demanding life engine.
• T-square: three planets, two in opposition plus a third squaring both. A tension you try to resolve through the "apex" planet (the top of the T).
• Yod ("finger of God"): two sextiles converging on an "apex" planet via two quincunxes. A rare configuration tied to a particular calling.

These configurations are more than the sum of the aspects that make them up. A Grand Trine is stronger than three separate trines, because it forms a closed system.

Why aspects are the dynamic part of the chart

Key idea. Without aspects, a natal chart is an inventory. With aspects, it is a system. Aspects tell you how the planets interact: which ones work together (trines, sextiles), which ones pull against each other (squares, oppositions), which ones fuse (conjunctions). That is what gives the chart its movement and its story.

When an astrologer says "you've got a heavy Mars-Saturn tension," they are talking about an aspect, not an isolated position. It is the meeting of the two that produces the meaning.

Visual conventions: reading Astrolabica's diagrams

On the classic 2D wheel, aspects appear as lines through the centre of the chart connecting the planets involved. Astrolabica uses a colour code by aspect type, not by "quality": each aspect gets its own hue so you can spot it at a glance.

One note: this colour code differs from the traditional French convention (red for tensions, blue for harmonies). Astrolabica favours an encoding by type rather than by valence, because the modern reading of astrology no longer judges aspects as "good" or "bad." Each has its role, and the colour is there to tell them apart, not to rank them.

The thickness of the line encodes the exactness of the aspect, meaning its orb:

• Thick line → orb under 2° (very tight, strongly active aspect)
• Medium line → orb between 2° and 5° (moderately active)
• Thin line → orb between 5° and the limit (a "light" aspect)

In practice, a Sun-Mars square at an orb of 0.5° gets drawn as a thick orange line, while a Saturn-Neptune sextile at an orb of 4.5° shows up as a thin blue thread. At a glance, you see which aspects "count" in the chart and which are just modulation.

Astrolabica also lets you view aspects in 3D in the planetarium and to filter by type or by orb through the layers panel, so the view never gets cluttered. Scrubbing the time cursor while an aspect forms is probably the best way to grasp how transit astrology works. Watching a Sun-Jupiter trine move from "almost exact" to "exact" then "separating" is how you feel time bring a chart to life.

Next chapter: reading a complete natal chart, where we finally put all the pieces together.