Astrology symbols: what the glyphs on a chart mean

By Nadia Reyes

Every mark on a birth chart belongs to one of four sets: ten planet glyphs, twelve sign glyphs, five aspect glyphs, and four angles marked with letters rather than symbols. Planets are the actors, signs describe the manner, aspects are the lines drawn between planets. The Ascendant sits on the left-hand edge, and the wheel runs counterclockwise.

What do the symbols on a birth chart mean?

A chart is a diagram of where things were in the sky, drawn in shorthand. The shorthand has four parts, and once the four are separated the page stops looking like noise.

The glyphs scattered around the rim, each with a number beside it, are the planets. The twelve glyphs marking the boundaries of the wheel's segments are the signs. The coloured lines crossing the middle, with small symbols on them or in a grid below, are the aspects — the angular distances between planets. The four letter-pairs at the compass points of the wheel are the angles.

The symbols themselves are old but not ancient in their current shapes. Planetary glyphs recognisably close to the modern ones appear in Byzantine Greek manuscripts copying late antique astrological texts, and the forms settled into something standard with Renaissance printing. The Venus and Mars glyphs only acquired their biological meaning in 1751, when Linnaeus borrowed them to mark the sexes of plants. They were astronomical and astrological symbols first by well over a thousand years.

What are the ten planet symbols?

Ten bodies appear on a standard modern chart: the Sun and Moon, which are not planets astronomically but are counted among them in astrological usage, the seven other bodies of the classical and modern sets, and Pluto, which has been classed as a dwarf planet since 2006 and which astrologers kept anyway. Classical astrology used seven, through Saturn. Uranus, Neptune and Pluto were added as they were discovered, in 1781, 1846 and 1930.

Planet What the glyph looks like What astrologers read it as
Sun ☉ A circle with a dot at its centre Core identity, vitality, the self in daylight
Moon ☽ A crescent Instinct, mood, what a person needs rather than wants
Mercury ☿ A circle with a small crescent on top and a cross below Thinking, speech, how information is handled
Venus ♀ A circle with a cross below it Attraction, taste, how a person values and relates
Mars ♂ A circle with an arrow leaving it to the upper right Drive, anger, how a person pushes
Jupiter ♃ A crescent fused to a vertical stroke with a crossbar, often read as a numeral 4 Expansion, belief, scale
Saturn ♄ A cross whose lower stroke runs into a curve, roughly an h with a crossbar Limit, structure, time, consequence
Uranus ♅ or ⛢ The first is a circle topped by a cross with a crescent to each side, which reads as a capital H and was meant to — it stands for Herschel, who discovered the planet. The second, used more in astronomy than astrology, is a dotted circle with an upright arrow Disruption, sudden change, deviation from the norm
Neptune ♆ A trident: a crescent pierced by a vertical stroke with a crossbar Dissolution, imagination, what is hard to see clearly
Pluto ♇ or ⯓ The first is a P with an L inside it, a monogram for Percival Lowell. The second is a bident, the two-pronged fork of Hades, with an orb between the prongs Compulsion, power, what cannot be negotiated with

The Uranus and Pluto readings are twentieth-century material. They have no classical pedigree because the planets have no classical existence, and traditional astrologers who work strictly from pre-modern sources leave all three outer planets off the chart entirely.

Other marks appear on many charts without belonging to the core ten. The lunar nodes — ☊ for the north node, shaped like a horseshoe with feet, and ☋ for the south, the same figure inverted — are the two points where the Moon's orbit crosses the ecliptic, the Sun's apparent path. They are mathematical points, not bodies. Chiron ⚷, a key shape, is a small body discovered in 1977. The Part of Fortune ⊗, a cross inside a circle, is a calculated point used heavily in Hellenistic astrology and described by Vettius Valens around 150 AD. Black Moon Lilith ⚸, a dark crescent over a cross, is modern.

What are the twelve sign glyphs?

Each sign occupies a 30-degree segment of the zodiac, and its glyph marks that segment's boundary on the wheel. Most of the figures are stylised pictures of the sign's image, worn down by centuries of copying.

Sign What the glyph looks like
Aries ♈ Two curved horns springing from a central stem
Taurus ♉ A circle with an arc resting on top: a bull's head and horns
Gemini ♊ A Roman numeral II closed with a bar top and bottom
Cancer ♋ Two curled forms facing opposite ways, like a sideways 69
Leo ♌ A small loop with a long curved tail rising out of it
Virgo ♍ An M whose last stroke curls back and crosses itself
Libra ♎ A horizontal bar with a half-circle sitting on it
Scorpio ♏ An M whose last stroke ends in an arrowhead pointing up and right
Sagittarius ♐ An arrow pointing up and right, crossed by a short bar
Capricorn ♑ A pointed V running into a looped tail: the goat-fish
Aquarius ♒ Two parallel zigzag lines
Pisces ♓ Two crescents back to back, joined by a horizontal bar

Scorpio and Virgo are the pair most often confused, and the difference is only the final stroke: Virgo's turns inward, Scorpio's turns into an arrow. Capricorn's glyph has a second common form that looks closer to a lowercase n with a flourish; both are correct and the variation is typographic rather than meaningful.

What are the aspect symbols?

Five aspects form the standard set. Four of them — opposition, trine, square and sextile — come from Ptolemy, who set them out in the Tetrabiblos in the second century. He did not count the conjunction among them, on the grounds that two planets in the same place are not looking at each other from a distance. They are the angular distances between two planets measured along the zodiac, and each corresponds to a simple division of the 360-degree circle.

Aspect Angle What the glyph looks like How it is read
Conjunction ☌ 0° A circle with a short arm extending up and to the right Two planets merged; the tradition reads them as acting as one
Sextile ⚹ 60° A six-pointed asterisk Opportunity that requires some effort to take up
Square □ 90° A plain square Friction, obstruction, the classic "hard" aspect
Trine △ 120° An equilateral triangle Ease, flow, and in traditional sources, sometimes complacency
Opposition ☍ 180° Two small circles joined by a straight line Tension held between two poles

Kepler added a second tier in Harmonices Mundi in 1619 — the quintile at 72 degrees, the semisquare at 45, and others — and modern astrologers vary in how many of these they use. A chart drawn with minor aspects switched on will have considerably more lines in it.

The lines are drawn between planet positions across the middle of the wheel. Most software colours them: red or orange for squares and oppositions, blue or green for trines and sextiles. The grid of symbols below the chart is the same information in table form, and is easier to read than the lines.

What are the four angles on a chart?

Four points mark the compass of a chart, and they are labelled with letters rather than glyphs.

All four are computed from the exact time and place of birth, which is why a chart without a birth time cannot show them. They move roughly one degree every four minutes. An hour's error in the birth time moves the Ascendant about fifteen degrees, which is often enough to change its sign.

Where is the Ascendant on the chart wheel?

On the left-hand edge, at the nine o'clock position. The horizontal line running across the middle of the wheel is the horizon, and the Ascendant is its left end, almost always labelled AC or ASC with a sign glyph and a degree figure beside it.

The sign glyph sitting at that point is the rising sign. The Midheaven is at or near the top of the wheel, the Imum Coeli at or near the bottom, the Descendant on the right.

Houses are numbered counterclockwise starting from the Ascendant: the first house begins there, the second below it, and so on round to the twelfth, which sits just above the Ascendant on the upper left. In quadrant house systems such as Placidus, the house segments are visibly unequal in size — that is correct and expected, not a rendering fault. In whole sign houses, each house is exactly one sign and the Ascendant falls somewhere inside the first house rather than exactly on its edge, and the Midheaven can land in the ninth, tenth or eleventh. Which system to use is one of the genuinely unsettled questions in the field.

Which way round is a birth chart drawn?

Counterclockwise, with east on the left. The convention comes from facing south to watch the sky in the northern hemisphere, which puts the eastern horizon on the observer's left hand. Degrees of the zodiac increase counterclockwise, house numbers increase counterclockwise, and the planets as a whole drift counterclockwise through the chart over a lifetime of symbolic motion.

What runs the other way is the daily rotation. Over the twenty-four hours after a birth, the actual sky turns clockwise through the wheel: a planet rising on the Ascendant climbs to the Midheaven about six hours later, sets on the Descendant after twelve, and reaches the Imum Coeli after eighteen. Both motions are real and they point in opposite directions on the page, which is the single most common source of confusion for a new reader.

What do the numbers and the R next to a planet mean?

Each planet carries its zodiac position: a degree from 0 to 29, the sign glyph, and usually minutes of arc. "♀ 14° ♊ 32′" means Venus at fourteen degrees and thirty-two minutes of Gemini. Degrees count from the start of each sign, so 29° of any sign is the last degree before the next one begins.

A small ℞ beside a planet means retrograde — the planet appeared, from Earth, to be moving backwards against the fixed stars at that moment. The backwards motion is apparent rather than actual, an effect of two bodies on curved orbits passing each other. It is a genuine astronomical fact about the view from here, and what it is taken to mean about a person is interpretation layered on top of it.

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