Guide
Astrology Glossary
A concise reference to the terms you meet when reading a natal chart in Astrolabe, from the angles and houses to the essential dignities and the techniques of astrological timing. Each entry defines the term precisely and, where it helps, points to the related concepts. They are ordered to move from the foundational ideas to the more advanced traditional techniques.
Natal chart
A natal chart is a map of the sky drawn for the exact time and place of birth: it plots the Sun, Moon and planets by sign and by house, together with the angles and the aspects between them. It is the founding document from which every reading in natal astrology proceeds.
Tropical & sidereal zodiac
The tropical zodiac, used in Western astrology, fixes 0° Aries at the spring equinox, so the signs follow the seasons rather than the constellations. The sidereal zodiac, used in Vedic astrology, is measured against the actual stars; the accumulated difference between the two, the ayanamsa, now stands at roughly 24°.
Ascendant (Rising sign)
The Ascendant, or rising sign, is the degree climbing over the eastern horizon at the moment of birth, and it defines the cusp of the first house. It shifts by roughly one sign every two hours, so it orients the whole chart, and its ruler acts as the ruler of the chart.
Descendant
The Descendant is the point diametrically opposite the Ascendant and marks the cusp of the seventh house. It describes what is sought and met in another: partnerships, close bonds and committed relationships.
Midheaven (MC)
The Midheaven (Medium Coeli, MC) is the highest point of the chart, where the zodiac crosses the meridian, and it usually marks the cusp of the tenth house. It signifies vocation, public standing and what one becomes known for.
Imum Coeli (IC)
The Imum Coeli (IC) is the lowest point of the chart and the exact opposite of the Midheaven; it marks the cusp of the fourth house. It is associated with home, family, roots and the private foundations of a life.
House
The houses are the twelve divisions of the chart that assign the sky to concrete areas of life — identity, resources, relationships, career — according to the daily rotation of the Earth. A planet expresses its nature in the field of the house it occupies.
House system
A house system is the geometric method by which the cusps of the twelve houses are calculated from the angles. Systems such as Placidus, Whole Sign and Koch divide the space differently, so a planet may fall in different houses depending on the one chosen.
Cusp
A cusp is the line that opens a house: the cusp of the first house is the Ascendant, and that of the tenth, the Midheaven. The term also denotes the boundary between two adjacent signs — a borderline placement that should always be confirmed with a precise calculation.
Aspect
An aspect is a significant angle between two planets or points, measured along the zodiac, that describes how their principles interact. The major aspects — conjunction, opposition, trine, square and sextile — arise from dividing the circle into simple fractions.
Orb
The orb measures how far an aspect departs from its exact angle. The smaller the orb, the stronger the aspect; a deviation of up to 2–3° is generally considered significant.
Applying & separating
An aspect is applying while the planets are still moving toward the exact angle: its influence is building and peaks when it becomes exact. It is separating once the exact angle has passed and the planets drift apart, with the influence fading.
Conjunction
The conjunction is the aspect of 0°: two bodies occupy virtually the same degree of the zodiac and their principles fuse. Its tone — harmonious or tense — depends on the planets involved, but it always concentrates and intensifies.
Opposition
The opposition is the aspect of 180°, with two planets facing each other across the chart. It sets up a polarity that calls for balance: the two energies tend to project onto each other until they are consciously integrated.
Trine
The trine is the aspect of 120°, joining planets usually of the same element. It is considered harmonious: energy flows effortlessly between the two, a natural talent that is sometimes taken for granted.
Square
The square is the aspect of 90°, a dynamic tension between planets of the same modality. It generates friction and obstacles, but also the impetus that forces action; it is the classic source of effort and development in a chart.
Sextile
The sextile is the aspect of 60°, gentler than the trine. It offers affinity and opportunity between the planets involved, but usually asks for some initiative before its potential takes concrete form.
Element (triplicity)
The four elements — fire, earth, air and water — sort the twelve signs into four triplicities of three signs each. The element describes a sign's underlying temperament: its characteristic way of directing and spending energy.
Modality (quadruplicity)
The three modalities — cardinal, fixed and mutable — divide the zodiac into quadruplicities of four signs. They describe the mode of operation: cardinal signs initiate, fixed signs sustain, and mutable signs adapt and transform.
Rulership
Rulership (or domicile) is the bond by which each sign is governed by a planet, which expresses its agenda there most directly. The ruler of the Ascendant sign becomes the ruler of the chart and orients the whole.
Essential dignity
Essential dignity gauges a planet's strength by the sign it occupies. In its domicile (rulership) or its exaltation a planet works at its best; in its detriment or fall, with its agenda strained. There are also minor dignities by triplicity, term and face.
Exaltation
Exaltation is a sign, distinct from a planet's own domicile, where it is considered honoured and elevated and acts at its best. The Sun, for instance, is exalted in Aries; it is the second strongest essential dignity after rulership.
Detriment & fall
These are the two essential debilities. In detriment a planet stands in the sign opposite the one it rules, and its agenda is strained and needs conscious effort. In fall it stands opposite its exaltation, its confidence undermined; growth comes through humility.
Retrograde
A retrograde planet appears to move backward through the zodiac, an optical effect of the relative positions of Earth and the planet. It is traditionally read as its themes turning inward: revision, delay and inner work.
Stationary
A stationary planet appears almost motionless as it changes direction, between direct and retrograde motion or the reverse. During these days its influence is considered especially concentrated and intense.
Lunar nodes (North & South)
The lunar nodes are the two points where the Moon's orbit crosses the ecliptic, always opposite each other. The North Node marks the direction of growth and what one is drawn to develop; the South Node, the familiar ground one tends to release.
Chiron
Chiron is a minor body orbiting between Saturn and Uranus, adopted into modern astrology. Known as the 'wounded healer', its position marks a sensitive, persistent wound that, once worked through, becomes a source of wisdom and of help to others.
Part of Fortune
The Part of Fortune is the best known of the hermetic lots, a point derived from the positions of the Sun, the Moon and the Ascendant, with different formulae for day and night charts (see sect). It marks the field of material well-being, the body and good fortune.
Sect (day & night chart)
Sect distinguishes day charts — with the Sun above the horizon — from night charts, with the Sun below. In a day chart the Sun, Jupiter and Saturn tend to work most constructively; in a night chart the Moon, Venus and Mars do.
Transit
A transit is a planet's position in the sky at a given moment and, above all, the aspect it makes to the points of the natal chart. It is the principal tool for reading the current period: the slow planets mark the weightiest cycles.
Secondary progression
Secondary progression is a symbolic technique of time: each day after birth corresponds to a year of life. Advancing the chart in this way traces inner maturation — above all that of the progressed Moon, which changes sign roughly every two and a half years.
Solar return
A solar return is the chart cast for the exact moment the Sun comes back to its natal degree, each year around the birthday. It is read as a portrait of the year ahead, set against the backdrop of the natal chart.
Synastry
Synastry compares two natal charts by overlaying them to study how their planets relate. The aspects between one chart and the other describe the attraction, the friction and the underlying dynamic of a bond.
Annual profection
Annual profection is a Hellenistic timing technique: each year of life advances the Ascendant one whole sign. The house so activated names the arena of the year, and its ruler becomes the lord of the year, whose natal condition and transits colour the entire period.
Zodiacal releasing
Zodiacal releasing (Vettius Valens) unfolds life in sign-ruled chapters counted from the Lot of Spirit; each sign holds its planetary years and the sub-periods repeat the pattern in months. Periods angular to the Lot of Fortune mark the peaks, and when a cycle completes it 'looses the bond', jumping to the opposite sign — a break in the narrative.
Declination (parallel & contraparallel)
Declination is a body's distance north or south of the celestial equator, a measure independent of the zodiac. Two planets at the same declination on the same side form a parallel, read like a hidden conjunction; on opposite sides they form a contraparallel, like a quiet opposition.
Antiscia
Antiscia are mirror points reflected across the solstice axis (0° Cancer–0° Capricorn). Two planets on each other's antiscia share equal daylight and are read as a concealed conjunction; the contra-antiscion mirror works like a concealed opposition.
Ephemeris
An ephemeris is a table recording the positions of the planets for each day. It is the source of astronomical data from which any chart is cast; Astrolabe uses the Swiss Ephemeris for degree-level precision.
A plain-language guide to the words you'll bump into when reading a birth chart in Astrolabe. No jargon here — just short, friendly explanations, starting with the basics and building up to the trickier bits.
Natal chart
Your natal chart is a snapshot of the sky at the exact moment and place you were born. It shows where the Sun, Moon, and planets were sitting, and everything an astrologer reads about you starts from this one map.
Tropical & sidereal zodiac
There are two ways to measure the zodiac. The tropical one lines up with the seasons and is used in Western astrology; the sidereal one lines up with the actual star constellations and is used in Indian (Vedic) astrology. Over the centuries they have drifted about 24° apart.
Ascendant (Rising sign)
The Ascendant, or Rising sign, is the sign that was coming up over the eastern horizon when you were born. It sets the starting point for your whole chart and shapes the first impression you give. It changes about every two hours, so your exact birth time really matters here.
Descendant
The Descendant sits directly opposite your Rising sign. It is the part of your chart about other people — partnerships, close relationships, and what you look for in someone else.
Midheaven (MC)
The Midheaven (or MC) is the highest point in your chart. It is linked to your career, your public role, and what you become known for out in the world.
Imum Coeli (IC)
The Imum Coeli (or IC) is the lowest point in your chart, sitting opposite the Midheaven. It is about home, family, your roots, and your private, personal side.
House
The chart is split into twelve houses, and each one covers a different part of life — things like money, relationships, or work. Whichever house a planet lands in tells you which area of your life it colours.
House system
A house system is simply the method used to draw the lines between the twelve houses. Astrologers use different methods (with names like Placidus or Whole Sign), and the one you pick can shift a planet from one house into the next.
Cusp
A cusp is the starting line of a house. The word is also used for the border between two neighbouring signs — and if you were born right on that border, it is worth checking with a real calculation to be sure which sign you are.
Aspect
An aspect is the angle between two planets, and it tells you how they get along. Some angles let planets work together smoothly, others create tension — either way, aspects are how the parts of your chart 'talk' to each other.
Orb
An aspect is rarely exact, and the orb measures how close it is to being perfect. The smaller the orb, the stronger the aspect; a gap of just a couple of degrees is usually enough to count.
Applying & separating
An aspect is applying while the two planets are still moving toward their exact angle — its effect is building and getting stronger. It is separating once that exact moment has passed and the planets drift apart, with the effect fading away.
Conjunction
A conjunction is when two planets sit right on top of each other in the same spot. Their energies blend and grow stronger together — whether that feels smooth or intense depends on which planets are involved.
Opposition
An opposition is when two planets sit on exactly opposite sides of the chart, facing off. It creates a push-and-pull that asks you to find a balance between the two.
Trine
A trine is an easy, comfortable angle between two planets. Their energies flow together naturally, like a talent that comes so easily you might not even notice it.
Square
A square is a tense angle between two planets that rubs them the wrong way. It can feel like friction or a challenge, but that pressure is often exactly what pushes you to act and grow.
Sextile
A sextile is a friendly, easygoing angle — a little gentler than a trine. It offers a helpful opportunity, but usually you have to make a bit of effort to get the most from it.
Element (triplicity)
The four elements — fire, earth, air, and water — sort the twelve signs into four groups of three. Your element gives the basic flavour of a sign: its general mood and how it spends its energy.
Modality (quadruplicity)
The three modalities — cardinal, fixed, and mutable — sort the signs by how they act. Cardinal signs get things started, fixed signs keep them going, and mutable signs go with the flow and adapt.
Rulership
Rulership is the link between a sign and the planet that 'runs' it, where that planet feels most at home. The planet that rules your Rising sign becomes the main planet steering your whole chart.
Essential dignity
Essential dignity is a way of measuring how comfortable a planet is in the sign it sits in. In some signs a planet is strong and works at its best; in others it struggles and has to try harder.
Exaltation
Exaltation is a sign where a planet is treated like an honoured guest — it is not its home, but it still performs at its best there. The Sun, for example, is exalted in Aries.
Detriment & fall
These are the two 'uncomfortable' spots for a planet. In detriment it sits opposite its home sign, so it has to work harder to do its job. In fall it sits in its weakest sign, where it feels less sure of itself and grows through patience.
Retrograde
Sometimes a planet looks like it is moving backward through the sky — that is called retrograde. It is really just a trick of perspective from Earth, but astrologers read it as a time to slow down, rethink, and turn inward.
Stationary
A planet is stationary when it seems to pause and stand still, right as it switches direction. Its influence is thought to be especially strong and focused during those few days.
Lunar nodes (North & South)
The lunar nodes are two points, always opposite each other, where the Moon's path crosses the Sun's. The North Node points to what you are growing toward; the South Node points to the old habits and comfort zones you are learning to let go of.
Chiron
Chiron is a small body orbiting between Saturn and Uranus, nicknamed the 'wounded healer'. Where it sits shows a tender, lasting hurt — and once you work through it, that same spot can become a source of wisdom and a way to help others.
Part of Fortune
The Part of Fortune is a special point worked out from your Sun, Moon, and Rising sign. It points to where you find well-being, good luck, and a sense of physical ease.
Sect (day & night chart)
Sect simply splits charts into day charts (born while the Sun was above the horizon) and night charts (born while it was below). Knowing which one you are helps show which planets are likely to work in your favour.
Transit
A transit is where a planet is in the sky right now, and the angle it makes to your birth chart. Transits are the main way astrologers read what is going on for you at the moment — the slow-moving planets mark the biggest chapters.
Secondary progression
Secondary progression is a symbolic way of tracking growth over time: each day after your birth stands for one year of your life. It gently shows how you mature on the inside, especially through the slowly moving progressed Moon.
Solar return
A solar return is a fresh chart drawn for the exact moment the Sun returns to the spot it was in when you were born — around your birthday each year. It is read as a preview of the year ahead.
Synastry
Synastry is what astrologers do when they compare two people's charts to see how they fit together. The angles between one chart and the other reveal the attraction, the friction, and the overall chemistry of a relationship.
Annual profection
Annual profection is a simple timing trick: with each birthday, the focus moves one whole sign forward. The area of life it lands on becomes the theme of your year, and the planet in charge of it becomes the year's key planet to watch.
Zodiacal releasing
Zodiacal releasing is a timing method that reads your life as a series of chapters, each ruled by a sign and lasting a set number of years. Some chapters stand out as high points, and when one finishes it jumps to the opposite sign — often marking a real turning point.
Declination (parallel & contraparallel)
Declination measures how far north or south a planet sits, separate from the usual zodiac. When two planets share the same measurement they form a parallel (read like a hidden conjunction); on opposite sides they form a contraparallel (like a quiet opposition).
Antiscia
Antiscia are mirror-image points, reflected across the line between 0° Cancer and 0° Capricorn. Two planets that mirror each other this way share a hidden bond, read a little like a secret conjunction.
Ephemeris
An ephemeris is a table listing where the planets are for each day. It is the raw data every chart is built from — Astrolabe uses the highly accurate Swiss Ephemeris.