Glossary

A glossary of the sky: 313 terms — astronomy, astrological tradition and AI, explained simply, with a clear line between the measurable and interpretation.

In Astronativa Celestial bodies Stars and constellations The Moon Coordinates Time Observing Signs Houses Aspects Techniques History AI

The terms in Astronativa

The sky · Measurable — astronomy.

Constellation: A named group of stars. There are 88 official ones; 12 lie along the ecliptic.
Eclipse: Solar — the Moon covers the Sun; lunar — the Moon passes through Earth's shadow.
Ecliptic: The path the Sun travels across the sky in a year. The planets and the Moon move close to it.; In Astronativa it is the golden arc.
Full Moon: Earth is between the Sun and the Moon; the Moon is fully lit.
Horizon: The line below which you can't see the sky from where you are. Planets below it are faded in Astronativa.
Local mean time: Before time zones every town had its own sun time. It matters for old birth dates.
Magnitude: How bright a star looks. The smaller the number, the brighter it is.
Moon phase: How much of the Moon is lit by the Sun, as seen from Earth.
New Moon: The Moon is between Earth and the Sun and barely visible. The start of the lunar month.
Precession: The slow wobble of Earth's axis — a full circle in about 26,000 years. It makes signs and constellations drift apart.
Retrograde motion: When a planet seems to move backwards across the sky. It is an optical effect — Earth overtakes it.
Sign and constellation: A sign is a 30° slice from the spring point; a constellation is a real group of stars. They don't match.; Because of precession, signs today are shifted about 24° from the constellations — the sign Aries lies mostly in the constellation Pisces.
Station: The moment a planet “stands still” before turning backwards or forwards.
Zodiac: The band around the ecliptic, divided into 12 equal parts of 30° — the signs.

Interpretation · Astrological tradition — for inspiration, not science.

7th house: The partner and agreements — that's what the “Partner” profile is for.
Ascendant: The sign rising in the east at the moment of birth. It needs an exact time.
Aspect: A set angle between two planets: conjunction 0°, sextile 60°, square 90°, trine 120°, opposition 180°.; The angle is measurable; what it “means” is interpretation.
Challenging aspects: Square and opposition — tradition sees them as friction calling for effort. “Shadow” shows these.
Electional astrology: Choosing a date and hour to begin — a wedding, a contract, a trip.
Elements: Fire, Earth, Air, Water — three signs in each.
Harmonious aspects: Sextile and trine — tradition sees them as easy and supportive. “Light” shows these.
Houses: The 12 areas of life in a chart — from “self” to “quiet and rest”. In Astronativa they count by whole signs from the ascendant.
MC (Midheaven): The highest point of the ecliptic above your place. Linked with one's calling.
Modalities: Cardinal (starts), fixed (holds), mutable (changes).
Natal chart: A snapshot of the sky at the moment and place you were born.
Orb: How many degrees off the exact angle still count as an aspect.
Retrograde shadow: The time before and after a retrograde when the planet crosses the same degrees.
Ruler: The planet tradition links to a sign — e.g. Venus to Taurus and Libra.
Sign horoscope: A general reading for everyone with a sign — by houses counted from the sign.
Synastry (two charts): Comparing two birth charts — where you complement and where you rub.
The big three: Your Sun, Moon and ascendant — the three most personal points in the chart.
Transit: A planet today making an aspect to a point in your birth chart.
Void-of-course Moon: The hours from the Moon's last aspect in a sign until it enters the next. Tradition advises not to start anything new.

Money · The money cards and the knowledge behind them.

2nd house: Your money, belongings and what you value.; More on money — Pecuvo our project
8th house: Shared money, loans, insurance, inheritance.; More on money — Pecuvo our project

AI · Artificial intelligence — a tool, not an oracle.

AI horoscope: A game: which AI tools “the stars favour” today. The sky is real, the AI link is a joke with a lesson.; AI by profession — KAGAMI Academy our project
AIscendant: A pun: which AI suits you by the stars.
Language model (LLM): The program behind ChatGPT, Claude, Gemini: it predicts the next word from a huge amount of text. It does not “know” the future.; How AI works — KAGAMI Academy our project
Local model: AI that runs on your own computer without sending data out.; How AI works — KAGAMI Academy our project
Prompt: What you write to an AI. The clearer you say what you want and for whom, the better the answer.; AI by profession — KAGAMI Academy our project

The full glossary

Celestial bodies (22)

Asteroidsky: An asteroid is a small rocky body orbiting the Sun. Most asteroids lie in the main asteroid belt between Mars and Jupiter.
Centaur (minor body)sky: Centaurs are icy small bodies orbiting among the giant planets. They share traits of both asteroids and comets.; Article →
Chironsky: Chiron is a small icy body orbiting between Saturn and Uranus, classified as a centaur. It also shows comet-like activity, hence the designation 95P.; Article →
Chiron in astrologytradition: In astrological tradition, Chiron is linked to the “wounded healer” theme: sensitive areas from which we may grow. It is a symbolic reading for reflection, not a diagnosis.; Article →
Cometsky: A comet is an icy body that warms up near the Sun and develops a glowing coma and a tail of gas and dust.; Article →
Dwarf planetsky: A dwarf planet orbits the Sun and is nearly round, but has not cleared its orbit of other objects. Pluto, Ceres and Eris are examples.; Article →
Earthsky: Earth is the third planet from the Sun and the only place we know to host life. It has one natural satellite, the Moon.; Article →
Jupitersky: Jupiter is the largest planet in our solar system, a gas giant famous for the Great Red Spot, a huge storm.; Article →
Lilith (Black Moon)tradition: In astrological tradition, Lilith is usually a calculated point in the Moon’s orbit, the one farthest from Earth. It symbolizes independence and hidden, uncomfortable sides of ourselves. It is not a physical body.; Article →
Marssky: Mars is the fourth planet from the Sun, known as the Red Planet because of iron-oxide dust on its surface. It has two small moons, Phobos and Deimos.; Article →
Mercurysky: Mercury is the closest planet to the Sun and the smallest in our solar system. It circles the Sun in about 88 Earth days.; Article →
Moonsky: The Moon is Earth’s only natural satellite. It shines in our night sky by reflecting sunlight from its surface.; Article →
Natural satellitesky: A natural satellite is a celestial body that orbits a planet or another body. The Moon is Earth’s natural satellite.
Neptunesky: Neptune is the most distant known planet from the Sun, a dark, cold and windy ice giant. It cannot be seen with the naked eye.; Article →
Planetsky: A planet is a celestial body that orbits the Sun, is nearly round, and has cleared the neighborhood around its orbit. This is the 2006 IAU (International Astronomical Union) definition for planets in our solar system.; Article →
Planets in astrologytradition: In astrological tradition each planet symbolizes a theme, such as the Moon for emotions and Mercury for communication. It is a cultural language for self-reflection, not a cause of events.; Article →
Plutosky: Pluto is a dwarf planet in the Kuiper Belt. It was counted as the ninth planet until 2006, when the IAU adopted a new definition of a planet.; Article →
Ruling planettradition: In astrological tradition each zodiac sign is symbolically linked to a ruling planet, for example Leo to the Sun. It is used to describe the sign’s character.; Article →
Saturnsky: Saturn is a gas giant famous for its spectacular ring system, made mostly of icy particles. It is the second-largest planet in the solar system.; Article →
Sunsky: The Sun is the star at the center of our solar system. Its light and warmth support life on Earth, and its gravity keeps the planets in orbit.; Article →
Uranussky: Uranus is an ice giant that rotates tilted almost on its side. It has faint rings and many moons.; Article →
Venussky: Venus is the second planet from the Sun and is similar to Earth in size. It has a thick atmosphere and is the brightest planet in our sky.; Article →

Stars and constellations (24)

Absolute magnitudesky: This is the brightness a star would have if it were placed at a standard distance of 10 parsecs. It lets us compare stars by their true luminosity.
Apparent magnitudesky: Apparent magnitude tells how bright a star looks from Earth. The scale runs backwards: the smaller (or more negative) the number, the brighter the object.; Article →
Asterismsky: An asterism is an easily recognized pattern of stars that is not an official constellation. It is often part of a larger constellation, like the Big Dipper within Ursa Major.; Article →
Betelgeusesky: Betelgeuse is a red supergiant in the constellation Orion and one of the brightest stars in the sky. Its brightness varies, so it is a variable star.; Article →
Cassiopeiasky: Cassiopeia is a northern constellation shaped like a W or an M. It lies on the opposite side of Polaris from Ursa Major.; Article →
Constellationsky: A constellation is a region of the celestial sphere with officially defined borders. The International Astronomical Union (IAU) recognizes 88 constellations covering the whole sky.; Article →
Light-yearsky: A light-year is the distance light travels in one year, about 9.46 trillion kilometres. It is a unit of distance, not of time.
Milky Waysky: The Milky Way is our galaxy, containing hundreds of billions of stars. From Earth we see it as a pale band of light across a dark sky.; Article →
Ophiuchussky: Ophiuchus is a large constellation that lies on the ecliptic between Scorpius and Sagittarius. The Sun passes through it every year from late November to mid-December.; Article →
Orionsky: Orion is one of the easiest constellations to recognize, with three stars forming its “belt”. It is seen in winter from the northern hemisphere and holds bright Rigel and Betelgeuse.; Article →
Pleiadessky: The Pleiades are a young star cluster in the constellation Taurus. With the naked eye you can usually make out about six or seven stars.; Article →
Polaris (North Star)sky: Polaris is located close to the north celestial pole, so it appears almost motionless while other stars circle around it. It helps us find north at night.; Article →
Sign vs constellationtradition: A sign is a 30° division of the tropical zodiac, while a constellation is a patch of sky with stars. Because of precession (the slow wobble of Earth’s axis), they no longer line up today.; Article →
Siriussky: Sirius is the brightest star in the night sky, in the constellation Canis Major. It is relatively close to us, about 8.6 light-years away.; Article →
Southern Cross (Crux)sky: The Southern Cross is a small but famous constellation of the southern sky. It is used to find south and is not visible from our latitudes.; Article →
Starsky: A star is a huge ball of hot gas that shines because nuclear fusion in its core releases energy. The nearest star to us is the Sun.; Article →
Star cataloguesky: A star catalogue is a list of stars with their positions and brightness. Modern examples come from ESA’s Hipparcos and Gaia missions.; Article →
Summer Trianglesky: The Summer Triangle is an asterism of three bright stars: Vega, Deneb and Altair. They belong to different constellations and ride high in the summer sky.; Article →
The 13 zodiac constellationssky: The Sun passes in front of 13 constellations along the ecliptic, spending a different length of time in each. The 12 astrological signs are equal divisions and do not match the constellations exactly.; Article →
The 88 constellationssky: This is the official division of the sky adopted by the IAU. Every point in the sky belongs to exactly one constellation, with borders fixed in the 20th century.; Article →
Tropical and sidereal zodiactradition: The tropical zodiac is measured from the spring equinox and is used in Western astrology. The sidereal zodiac is measured against the stars and is used, for example, in Vedic astrology.; Article →
Ursa Majorsky: Ursa Major is a large northern constellation. Its seven bright stars form the Big Dipper, which can be used to find Polaris.; Article →
Zodiac constellationssky: These are the constellations the ecliptic, the Sun’s apparent path across the sky, passes through. Astronomically there are 13, since Ophiuchus joins the classical 12.; Article →
Zodiac signstradition: In the astrological tradition the zodiac is a circle of 12 equal 30° divisions starting at the spring equinox point. The signs are a cultural framework for symbolic reading, not a scientific division of the sky.; Article →

The Moon (25)

Annular eclipsesky: An annular eclipse occurs when the Moon is farther from Earth and looks too small to cover the Sun completely. A bright ring remains around it.; Article →
Apogeesky: Apogee is the point in the Moon's orbit where it is farthest from Earth. The Moon then looks slightly smaller in the sky.; Article →
Ascending nodesky: The ascending node is where the Moon crosses the ecliptic from south to north. The opposite point is the descending node.; Article →
Blood Moonsky: “Blood Moon” is a popular name for the Moon during a total lunar eclipse, when it turns reddish. The colour comes from Earth's atmosphere bending red light onto the Moon.; Article →
Blue Moonsky: A Blue Moon is the second Full Moon in a calendar month or, by another definition, the third of four Full Moons in a season. It does not mean the Moon is blue in colour.; Article →
Eclipsesky: An eclipse occurs when one celestial body moves into the shadow of another or is hidden by it. For Earth, the best known are solar and lunar eclipses.
Eclipse seasonsky: An eclipse season is a window of roughly a month and a half when the Sun is near a lunar node, so solar and lunar eclipses are possible. There are about two such seasons a year.; Article →
Eclipses in astrologytradition: In the astrological tradition eclipses are linked with endings, new beginnings and reflection. This is cultural interpretation: eclipses do not cause events in our lives, but can be a prompt to pause and reflect.; Article →
First quartersky: First quarter is the phase a quarter of the way around Earth after New Moon. We see half of the Moon's disk lit.; Article →
Full Moonsky: Full Moon is the phase when Earth lies roughly between the Sun and the Moon, so the whole face turned toward us is lit. The Moon rises around sunset.; Article →
Lunar eclipsesky: A lunar eclipse happens at Full Moon, when the Moon passes through Earth's shadow. It can be watched with the naked eye from the whole night side of the planet.; Article →
Lunar nodessky: The lunar nodes are the two points where the Moon's orbit crosses the plane of the ecliptic. Eclipses happen only when a New or Full Moon falls near a node.; Article →
Lunar orbitsky: The lunar orbit is the Moon's path around Earth. It is slightly elliptical and tilted about 5° to the ecliptic (the Sun's apparent path).; Article →
Lunar phasesky: A lunar phase is the portion of the Moon's sunlit side that we can see from Earth. It changes as the Moon orbits us and the angle between the Sun, Moon and observer shifts.; Article →
Micromoonsky: A micromoon is a Full Moon that happens near apogee. The Moon appears slightly smaller and dimmer than usual.; Article →
New Moonsky: New Moon occurs when the Moon lies roughly between Earth and the Sun, so its unlit side faces us. The Moon is then almost invisible in the sky.; Article →
North Node (in astrology)tradition: In the astrological tradition the North Node symbolises a direction of growth and unfamiliar lessons, while the South Node stands for familiar habits. This is symbolic interpretation, not a scientific claim.; Article →
Perigeesky: Perigee is the point in the Moon's orbit where it is closest to Earth. The orbit is an ellipse, so the distance varies.; Article →
Sarossky: The Saros is a period of about 18 years and 11 days after which the Sun, Earth and Moon return to nearly the same geometry. Eclipses therefore repeat in similar series.; Article →
Solar eclipsesky: A solar eclipse happens at New Moon, when the Moon passes in front of the Sun and casts a shadow on part of Earth. Never look at the Sun without proper eye protection.; Article →
Supermoonsky: A supermoon is a Full or New Moon that occurs near the Moon's perigee. A full supermoon looks slightly larger and brighter, though the difference is subtle.; Article →
Synodic monthsky: The synodic month is the time between two identical lunar phases, such as New Moon to New Moon. It lasts about 29.5 days.; Article →
Total solar eclipsesky: In a total solar eclipse the Moon completely covers the Sun's disk for observers in a narrow path on Earth. The solar corona then becomes visible.; Article →
Waning Moonsky: The Moon is waning between Full and New Moon, as its lit part gradually shrinks. In the Northern Hemisphere the lit part is on the left.; Article →
Waxing Moonsky: The Moon is waxing between New and Full Moon, when its lit part grows from day to day. In the Northern Hemisphere the lit part is on the right.; Article →

Coordinates (21)

Axial tiltsky: Earth's rotation axis is tilted by about 23.4° relative to the perpendicular to its orbital plane. This tilt is what causes the seasons.; Article →
Azimuth and altitudesky: Horizontal coordinates tell you where to look from a specific place and time. Azimuth is the compass direction along the horizon, and altitude is the angle above it.; Article →
Celestial equatorsky: The celestial equator is the Earth's equator projected out onto the celestial sphere. It divides the sky into a northern and a southern half.
Celestial polesky: The celestial poles are the points on the sky where Earth's rotation axis points. Because Earth rotates, the stars appear to circle around them.; Article →
Celestial spheresky: The celestial sphere is an imaginary sphere around Earth on which stars and planets appear projected. Astronomers use it to describe where something is in the sky without needing its distance.
Declinationsky: Declination is the angular distance of an object north or south of the celestial equator, much like latitude on Earth. It is measured in degrees.
Diurnal motionsky: The Sun, Moon and stars seem to travel from east to west each day. In reality this is caused by Earth rotating on its axis.; Article →
Ecliptic coordinatessky: This system uses the ecliptic as its reference plane. It is convenient for describing the positions of the Sun, Moon and planets.; Article →
Elongationsky: Elongation is the angle between a planet and the Sun as seen from Earth. For Mercury and Venus, greatest elongation is the best time to observe them.; Article →
Equatorial coordinate systemsky: This is the most widely used system for pinpointing objects in the sky. A position is given by right ascension and declination, and it does not depend on the observer's location.
Equinoxsky: An equinox is the moment the Sun crosses the celestial equator, making day and night nearly equal in length. It happens twice a year, in March and September.; Article →
March equinox point (vernal point)sky: This is the point where the Sun crosses the celestial equator from south to north. Right ascension is measured from it, and the tropical zodiac begins there at 0° Aries.; Article →
Nadirsky: The nadir is the point opposite the zenith, directly beneath the observer's feet. It can never be seen, as it lies below the horizon.
Oppositionsky: Opposition occurs when an outer planet lies on the opposite side of the sky from the Sun. It rises at sunset and is best placed for observing.; Article →
Precessionsky: Precession is the slow wobble of Earth's axis, like that of a spinning top. A full cycle takes about 26,000 years and shifts the celestial poles and the equinox points.; Article →
Prograde (direct) motionsky: This is the usual apparent motion of planets against the stars, from west to east. Planets move this way most of the time.; Article →
Retrograde motionsky: At times a planet appears to move backward against the background stars. This is an apparent effect of perspective caused by the differing orbital speeds of Earth and the planet.; Article →
Retrograde planets (in astrology)tradition: In the astrological tradition, a retrograde planet is linked with review, reflection and slowing down. This is a symbolic reading, not a cause of events, and can be taken as a calm prompt for reflection.; Article →
Right ascensionsky: Right ascension is the sky's counterpart of longitude: the angle of an object measured eastward from the March equinox point. It is usually given in hours, minutes and seconds.
Solsticesky: A solstice is when the Sun reaches its northernmost or southernmost point in the sky. It marks the longest and shortest days of the year.; Article →
Stationary pointsky: A stationary point is when a planet seems to pause against the background stars before changing direction, from direct to retrograde motion or the other way round.; Article →

Time (17)

Axial tiltsky: Earth’s axis is tilted by about 23.4° relative to its orbital plane. This tilt is what causes the seasons.; Article →
Coordinated Universal Time (UTC)sky: UTC is the world standard for time, from which all time zones are defined. It is based on atomic clocks and kept in step with Earth’s rotation.; Article →
Ephemeris accuracyAI: Astronomical positions come from data and mathematical models, not from a language model’s guesswork. That is why Astronativa relies on calculation, with AI only helping to explain.; Article →
Gregorian calendarsky: The Gregorian calendar is the solar calendar used across most of the world today. It was introduced in 1582 as a refinement of the Julian calendar to keep better pace with the seasons.
Julian calendarsky: The Julian calendar was established by Julius Caesar’s reform of 46 BC and took effect in 45 BC. It has 365 days plus a leap day every four years, so its average year is slightly longer than the tropical year, so it slowly drifts out of step with the seasons.
Julian datesky: The Julian date is a continuous count of days, with a decimal fraction, from a fixed starting point in antiquity. Astronomers use it to compare moments easily without worrying about months and leap years.
Leap yearsky: A leap year has one extra day, 29 February. It is added because the tropical year is not exactly 365 days, which keeps the calendar in step with the seasons.
Local timesky: Local time is the time shown on clocks at a given place according to its time zone. It matters when calculating the sky for a specific city and moment.; Article →
Lunar calendarsky: A lunar calendar counts months by the phases of the Moon. Some cultures and religious traditions use one, often alongside a solar calendar.; Article →
Perihelion and aphelionsky: Perihelion is the point in Earth’s orbit closest to the Sun, and aphelion is the farthest point. Earth reaches perihelion in early January.; Article →
Seasonssky: The seasons come from Earth’s axial tilt, not from its distance to the Sun. Over the year, each hemisphere receives a different amount of sunlight.; Article →
Sidereal daysky: A sidereal day is the time Earth takes to turn once relative to the distant stars, about 23 hours and 56 minutes. A solar day is slightly longer because Earth is also moving around the Sun.; Article →
Sidereal timesky: Sidereal time tells you which part of the sky is crossing your local meridian (the imaginary north–south line through the point overhead) right now. It is measured against the stars rather than the Sun, so a sidereal day is a little shorter than our everyday day.; Article →
Sidereal yearsky: The sidereal year is the time Earth takes to complete one full orbit around the Sun relative to the distant stars. It is about 20 minutes longer than the tropical year because of precession.; Article →
Solar timesky: Solar time is based on the position of the Sun in the sky. In true solar time, noon is when the Sun is at its highest point above the horizon.; Article →
Time zonessky: Time zones are regions of the Earth that share the same official clock time. They exist because the Sun rises and sets at different moments along different longitudes.; Article →
Tropical yearsky: The tropical year is the time between two successive March equinoxes, about 365.24 days. Our calendar is built on it, which keeps the seasons in the same place each year.; Article →

Observing (23)

Aperturesky: Aperture is the diameter of the main lens or mirror of a telescope or binoculars. It determines how much light is collected and how fine a detail you can resolve.; Article →
Apparent magnitudesky: Apparent magnitude measures how bright an object looks from Earth. The scale runs backwards: a smaller number means a brighter object, and under dark skies the naked eye reaches about magnitude 6.; Article →
Binocularssky: Binoculars are a pair of matched telescopes you look through with both eyes. They are a great start for beginners, showing lunar craters, Jupiter’s moons and star clusters. Sizes are written like 10×50: magnification × lens diameter in millimetres.; Article →
Bortle scalesky: The Bortle scale is a nine-level measure of night-sky darkness. Class 1 is the darkest sky, while class 9 is the inner-city sky.; Article →
Constellationsky: A constellation is a region of the sky with boundaries set by the International Astronomical Union (IAU), often named after a star pattern. There are 88 in total, covering the whole sky.; Article →
Dark adaptationsky: Dark adaptation is how your eyes adjust to darkness. It usually takes about 20–30 minutes to see fainter stars; white light undoes it, so observers use a red torch.; Article →
Dark skysky: A dark sky is a place with little artificial light where many stars are visible. The farther you go from town, the better, and the Milky Way becomes clearly visible.; Article →
Dobsonian telescopesky: A Dobsonian is a reflector telescope on a simple swivelling base that moves left-right and up-down. It is easy to use and offers a large aperture at a fair price.; Article →
Eyepiecesky: The eyepiece is the swappable lens you look through on a telescope. Changing it changes the magnification.; Article →
Light pollutionsky: Light pollution is excess or poorly aimed artificial lighting that washes out the night sky. Because of it, far fewer stars are visible from cities, and the Milky Way is often not visible at all.; Article →
Magnificationsky: Magnification tells you how many times larger an object appears. It equals the telescope’s focal length divided by the eyepiece’s focal length. More magnification does not always mean a better view.; Article →
Meteor (shooting star)sky: A meteor is the streak of light seen when a small space particle burns up in Earth’s atmosphere. It has nothing to do with a real star.; Article →
Meteor showersky: A meteor shower is a period when more shooting stars appear. It happens when Earth passes through a cloud of dust and debris, most often left behind by a comet.; Article →
Perseidssky: The Perseids are a meteor shower peaking around mid-August, with a radiant in the constellation Perseus. It is linked to comet Swift–Tuttle and is one of the most popular summer showers.; Article →
Planetariumsky: A planetarium is a domed theatre where the night sky is projected onto the ceiling. It lets you see stars and planets at any time, whatever the weather.
Planispheresky: A planisphere is a rotating star chart made of two discs. Set the date and time, and it shows which stars are above the horizon.; Article →
Radiantsky: The radiant is the point in the sky from which the meteors of a shower seem to originate. It is an effect of perspective, since the particles travel on nearly parallel paths. A shower is usually named after the constellation of its radiant.; Article →
Reflector telescopesky: A reflector is a telescope that gathers light with a curved mirror. It offers a large aperture for the price, which makes it popular for viewing nebulae and galaxies.; Article →
Refractor telescopesky: A refractor is a telescope that gathers light with a lens. It is usually low-maintenance and gives crisp, high-contrast views of the Moon and planets.; Article →
Star chartsky: A star chart is a map of the stars and constellations, often as seen from a given place and time. It helps you find familiar patterns and find your way around the sky.; Article →
Telescopesky: A telescope gathers light from distant objects and makes them look brighter and larger. The larger its aperture (the diameter of the lens or mirror), the more light it collects.; Article →
Telescope mountsky: A mount is the support that holds a telescope and lets you aim it. A steady mount matters at least as much as the telescope itself.; Article →
ZHR (zenithal hourly rate)sky: ZHR is the theoretical number of meteors per hour one observer would see under a perfectly dark sky with the radiant overhead. In practice you usually see fewer.; Article →

Signs (24)

Air signstradition: Gemini, Libra and Aquarius are the air signs. Tradition associates them with thought, communication, ideas and connections between people.; Article →
Aquariustradition: An air and fixed sign. Tradition links it with independence, original ideas and a sense of community.; Article →
Ariestradition: The first sign of the zodiac, fire and cardinal. Tradition presents it as a symbol of courage, new beginnings and directness.; Article →
Cancertradition: A water and cardinal sign. In tradition it symbolises home, care and emotional sensitivity.; Article →
Capricorntradition: An earth and cardinal sign. In tradition it symbolises determination, responsibility and patience.; Article →
Cardinal signstradition: Aries, Cancer, Libra and Capricorn open the seasons and in tradition symbolise beginnings, impulse and taking initiative.; Article →
Earth signstradition: Taurus, Virgo and Capricorn are the earth signs. In tradition they symbolise practicality, steadiness and care for tangible things.; Article →
Eclipticsky: The ecliptic is the Sun’s apparent yearly path across the sky, the projection of the plane of Earth’s orbit onto the celestial sphere. The astrological zodiac is measured along this line.; Article →
Elementstradition: In astrological tradition the 12 signs are grouped into four elements: fire, earth, air and water. Each element describes a particular style of experiencing and expressing things.; Article →
Fire signstradition: Aries, Leo and Sagittarius are the fire signs. Tradition links them with energy, enthusiasm, initiative and inspiration.; Article →
Fixed signstradition: Taurus, Leo, Scorpio and Aquarius fall in the middle of the seasons. Tradition links them with stability, persistence and loyalty.; Article →
Geminitradition: An air and mutable sign. Tradition links it with curiosity, speech, learning and versatility.; Article →
Leotradition: A fire and fixed sign. Tradition associates it with generosity, creativity and the wish for self-expression.; Article →
Libratradition: An air and cardinal sign. Tradition links it with balance, partnership and a search for harmony.; Article →
Modalities (crosses)tradition: Besides elements, signs are divided into three modalities, or crosses: cardinal, fixed and mutable. They describe how a sign relates to change and to the turning of the seasons.; Article →
Mutable signstradition: Gemini, Virgo, Sagittarius and Pisces come at the end of the seasons. In tradition they symbolise flexibility, adaptation and transition.; Article →
Sagittariustradition: A fire and mutable sign. Tradition associates it with travel, optimism and a search for meaning.; Article →
Scorpiotradition: A water and fixed sign. In tradition it symbolises depth, passion and transformation.; Article →
Sun signtradition: This is the sign the Sun was in on your birth date. In popular horoscopes it is simply called “your sign”.; Article →
Taurustradition: An earth and fixed sign. Tradition associates it with steadiness, enjoyment of beauty and a search for security.; Article →
Virgotradition: An earth and mutable sign. In tradition it symbolises attention to detail, order and a wish to be useful.; Article →
Water signstradition: Cancer, Scorpio and Pisces are the water signs. In tradition they are linked with feeling, intuition, imagination and empathy.; Article →
Zodiac signtradition: A zodiac sign is one of the 12 sections of 30° along the ecliptic (the Sun’s apparent path). Tradition gives each sign its own character and symbolism, offered as food for reflection and inspiration.; Article →
Zodiacal constellationssky: These are the constellations the ecliptic passes through. They vary in size and do not match the equal 30° astrological signs.; Article →

Houses (25)

Angles of the charttradition: The four angles are the Ascendant, Descendant, MC and IC. They are calculated from the time and place of birth and form the basic frame of a natal chart.; Article →
Angular, succedent and cadent housestradition: Tradition groups houses into angular (1, 4, 7, 10), succedent (2, 5, 8, 11) and cadent (3, 6, 9, 12). Angular houses are considered the most prominent in a chart.; Article →
Ascendant (rising sign)tradition: The Ascendant is the point of the ecliptic (the Sun’s apparent yearly path) rising on the eastern horizon at the moment and place of birth. In the astrological tradition it marks the start of the first house and is linked to first impressions and outward style.; Article →
Astrological housetradition: A house is one of the 12 divisions of the sky around the birthplace in a natal chart. In the astrological tradition each house relates to an area of life, such as home, work or relationships.; Article →
Birth timetradition: Exact birth time is the key input for houses. The Ascendant changes sign on average about every two hours, so a few minutes can shift its degree.; Article →
Celestial meridiansky: The celestial meridian is an imaginary great circle through the celestial poles, the zenith and the nadir; above the horizon it runs from north through the zenith to south. An object crossing its upper part is at its highest point for the day. The MC and IC lie on it.; Article →
Chart with unknown birth timetradition: When the birth time is unknown, the Ascendant and houses cannot be determined reliably. A noon chart or planets-by-sign reading is often used instead.; Article →
Cusptradition: A cusp is the boundary point where one house begins and the previous one ends. For example, in most systems the cusp of the first house coincides with the Ascendant.; Article →
Descendanttradition: The Descendant is the point setting on the western horizon, directly opposite the Ascendant. In the astrological tradition it is the cusp of the seventh house and is associated with partnerships and how we relate to others.; Article →
Eclipticsky: The ecliptic is the Sun’s apparent yearly path across the sky – the projection of the plane of Earth’s orbit onto the celestial sphere. Planets travel close to it, and the astrological zodiac is measured along it.; Article →
Equal house systemtradition: In the equal house system every house spans exactly 30° starting from the exact degree of the Ascendant. It is simple and also works at high latitudes.; Article →
High latitudes and housessky: Beyond the polar circles some points of the ecliptic never rise or never set. That is why systems like Placidus cannot be computed there, and equal or whole sign houses are often used instead.; Article →
Horizonsky: The horizon is the line where the sky appears to meet the ground. It separates what is above from what is below the observer and underlies the Ascendant and Descendant.; Article →
House rulertradition: The house ruler is the planet that tradition associates with the sign on the house’s cusp. For example, with Aries rising, Mars rules the first house.; Article →
House systemtradition: A house system is the method used to divide the sky into 12 houses. Different systems give different cusps, so the same chart can look slightly different depending on the choice.; Article →
IC (Imum Coeli, bottom of the sky)tradition: The IC is the point directly opposite the MC, at the lowest part of the chart below the horizon. In the astrological tradition it is the cusp of the fourth house and stands for roots, family and home.; Article →
Koch house systemtradition: The Koch system is another time-based house system, popular in parts of modern astrology. Like Placidus, it produces houses of unequal size.; Article →
MC (Medium Coeli, Midheaven)tradition: The MC is the point of the ecliptic crossing the local meridian at the time of birth, at its highest position above the horizon. In the astrological tradition it is linked with vocation, goals and public image.; Article →
Placidus house systemtradition: Placidus is one of the most widely used systems in Western astrology. It divides the time points take to travel between horizon and meridian, so houses come out with unequal sizes.; Article →
Planet in a housetradition: When a planet falls within a house’s sector, tradition links its symbolism with that area of life. It is an interpretation for reflection, not a prediction.; Article →
Sidereal timesky: Sidereal time measures Earth’s rotation relative to the distant stars. It is needed to work out which degree of the ecliptic is on the meridian and the horizon at a given moment.; Article →
Vertextradition: The Vertex is a calculated point in the western part of the chart where the ecliptic crosses the prime vertical. Some astrologers use it as an extra point, though it is not among the main ones.
Which house system to choose?AI: There is no single “correct” system; astrologers choose by school and habit. A good approach is to compare two systems and notice which themes stay constant.; Article →
Whole sign housestradition: In whole sign houses the first house is the entire zodiac sign containing the Ascendant, and each following sign is the next house. It is among the oldest known approaches.; Article →
Zenithsky: The zenith is the point in the sky directly above the observer. It lies on the celestial meridian and helps explain how houses are drawn for a specific place.

Aspects (26)

Angular separationsky: Angular separation is the apparent angle between two objects on the sky, measured in degrees. It is related to the idea of an aspect, but aspects are calculated only from the difference in ecliptic longitude, not from the full angular separation. It says nothing about how far apart the objects really are in space.
Applying aspecttradition: An applying aspect is one where the planets are moving toward the exact angle. Tradition links it with anticipation and a theme still taking shape.; Article →
Aspecttradition: In astrological tradition, an aspect is a specific angle between two planets or points in a chart, measured along the ecliptic. Tradition reads it as a symbolic “conversation” between two themes. It is a cultural language for reflection, not a cause of events.; Article →
Aspect with a retrograde planettradition: When a planet appears to move backward, its aspects can become exact up to three times. Retrograde motion is an apparent effect of Earth’s motion relative to the planet. Tradition treats it as a chance to rethink, without fear.; Article →
Conjunctiontradition: A conjunction is a 0° aspect: two planets appear at the same ecliptic longitude. Astrological tradition reads it as a blending and emphasis of their themes. Astronomically it is only an apparent alignment, not real closeness.; Article →
Eclipticsky: The ecliptic is the Sun’s apparent yearly path across the sky, matching the plane of Earth’s orbit. The planets stay close to it, so aspects are counted along its longitude.; Article →
Elements and aspectstradition: Trines link signs of the same element, while sextiles link compatible elements (fire with air, earth with water). Squares and oppositions link signs of the same modality but different elements. This is how tradition ties angles to signs.; Article →
Exact aspecttradition: An aspect is exact when the angle between two planets matches the ideal one, such as exactly 90°. Tradition then speaks of the theme at its most pronounced. The exact moment is computed from ephemerides.; Article →
Full Moon as an oppositionsky: At Full Moon, Earth lies between the Sun and Moon, which sit at opposite ecliptic longitudes. It is an astronomical event that astrology describes as a Sun–Moon opposition.; Article →
Grand crosstradition: A grand cross is a pattern of four planets forming a square of squares and two oppositions. Tradition sees many tensions seeking balance. It is fairly rare and read as an invitation to patience.
Grand trinetradition: A grand trine is a pattern of three planets forming an equilateral triangle of 120° trines. Tradition often places it within one element and sees it as talent and ease worth using consciously.
Major (Ptolemaic) aspectstradition: The five major aspects are conjunction (0°), sextile (60°), square (90°), trine (120°) and opposition (180°). They are called Ptolemaic after Claudius Ptolemy, the ancient figure associated with them.; Article →
Minor aspectstradition: Minor aspects are less commonly used angles such as the quincunx (150°), semi-sextile (30°) and semi-square (45°). They usually take tighter orbs and carry subtler symbolism.; Article →
New Moon as a conjunctionsky: At New Moon, the Moon lies between Earth and Sun at nearly the same ecliptic longitude. Astrology calls it a Sun–Moon conjunction and links it with symbolic fresh starts.; Article →
Oppositiontradition: The opposition is a 180° aspect: two planets lie on opposite sides of the sky. Tradition reads it as a theme of balance and seeing the other side. The Full Moon is a familiar astronomical opposition of the Sun and Moon.; Article →
Orbtradition: The orb is the allowed deviation, in degrees, from an aspect’s exact angle. In tradition, the tighter the orb, the “stronger” the aspect. Astrologers use different values, so there is no single rule.; Article →
Quincunxtradition: The quincunx, or inconjunct, is a 150° aspect. It links signs that share no element or modality. Tradition associates it with adjustment and small course corrections.
Separating aspecttradition: A separating aspect is one where the planets have passed the exact angle and are moving apart. Tradition associates it with reflection and the winding down of a theme already expressed.; Article →
Sextiletradition: The sextile is a 60° aspect, one sixth of the circle. Tradition sees it as harmonious and supportive, like an open door you may walk through if you wish.; Article →
Squaretradition: The square is a 90° aspect, a quarter of the circle. Tradition associates it with a tension that nudges us toward action. It can be taken calmly, as a prompt to reflect on what we want to change.; Article →
Stelliumtradition: A stellium is a cluster of three or more planets in one sign or house. Tradition sees it as emphasis on a theme that draws strong focus. Practitioners differ on how many planets and what orb to count.
Synastry aspectstradition: Synastry aspects are the angles between planets in two natal charts. Tradition reads them as a symbolic language for the themes between two people. They do not decide whether a relationship will work.; Article →
T-squaretradition: A T-square is a pattern in which two planets are in opposition and a third squares both. Tradition sees it as dynamic tension and motivation. The apex is read as the theme where attention is drawn.
Transit aspectstradition: Transit aspects are the angles between today’s planets and the planets in a natal chart. Tradition uses them as prompts for reflecting on current themes. They do not predict events.; Article →
Trinetradition: The trine is a 120° aspect, one third of the circle. It links signs of the same element and, in tradition, suggests ease and natural flow. Ease can also be an invitation not to get too comfortable.; Article →
Yodtradition: A yod is a pattern of two planets in sextile that both form a quincunx to a third. Tradition links it with a sense of searching for direction. The nickname “Finger of Fate” is figurative and implies no predestination.

Techniques (15)

Aspectstradition: Aspects are specific angular distances between planets in a chart, such as 0°, 60°, 90°, 120° and 180°. Tradition reads them as a kind of dialogue between planets.; Article →
Composite charttradition: A composite chart is built from the midpoints between matching planets in two natal charts. In astrological tradition it is read as a symbolic portrait of the relationship itself.
Detrimenttradition: Detriment is the sign opposite a planet’s domicile. Tradition describes it as a place where the planet’s qualities find expression less easily, a gentle invitation to attention rather than worry.
Essential dignitiestradition: Essential dignities are a traditional system describing how comfortably a planet expresses itself in a given sign. It includes rulership, exaltation, detriment and fall.; Article →
Exaltationtradition: Exaltation is a sign where, in tradition, a planet is especially honoured and expresses its qualities in their best light. For example, the Sun is exalted in Aries.
Falltradition: Fall is the sign opposite a planet’s exaltation. In tradition it means the planet expresses itself with less ease and may invite more awareness.
Housestradition: Houses are 12 divisions of the sky around the birthplace. Each is linked with an area of life, such as home, work or friendship.; Article →
Lunar returntradition: A lunar return is the chart for the moment the Moon returns to its natal position, roughly once a month. Tradition uses it to reflect on the mood and themes of the coming month.; Article →
MC (Midheaven)tradition: The MC (Latin Medium Coeli, “middle of the sky”) is the point where the ecliptic crosses the upper part of the local meridian above the birthplace. Tradition links it with vocation and life direction.; Article →
Progressionstradition: Progressions are a technique that symbolically moves a natal chart forward in time. The best known is secondary progression, where one day after birth stands for one year of life.
Rulership (domicile)tradition: A ruler is the planet tradition associates with a particular sign, such as Venus with Taurus. The planet is said to be “at home” there.; Article →
Saturn returntradition: The Saturn return is when Saturn comes back to its natal position, at around age 29–30. Tradition links it with maturing and reassessing direction, a time for reflection.; Article →
Solar returntradition: A solar return is the chart for the moment the Sun returns to its exact natal position, around your birthday. Tradition reads it as a theme for the year ahead, offered for inspiration.; Article →
Synastrytradition: Synastry compares two natal charts to explore how two people’s symbols interact. In the tradition it is used as a conversation starter and a way to understand each other, not as a verdict on a relationship.; Article →
Transitstradition: Transits compare where the planets are now with the positions in a natal chart. Astrological tradition treats them as prompts for reflecting on the present moment, not as causes of events.; Article →

History (25)

Almagestsky: Ptolemy’s astronomical treatise with a mathematical model of the motions of the Sun, Moon and planets, plus a star catalogue. It served as a standard textbook for centuries.
Ayanamshatradition: The angular difference between the tropical and sidereal zodiacs. It grows slowly because of precession and comes in several versions, the Lahiri being best known.; Article →
Babylonian astrologytradition: In tradition, these were celestial omens recorded in Mesopotamia: eclipses, planetary appearances and other events were read as signs concerning the kingdom. Personal horoscopes appeared later.; Article →
Babylonian astronomysky: Systematic sky observations kept by scribe-priests in ancient Mesopotamia on clay tablets. They are among the earliest long written records of the motions of the Moon and planets.; Article →
BaZi (Four Pillars)tradition: A Chinese tradition describing the moment of birth through four pairs of characters: year, month, day and hour. It serves as a symbolic language, not a scientific forecast.; Article →
Chinese zodiactradition: A cycle of 12 animals, each tied to a year in the lunisolar calendar. In tradition it offers a symbolic way to describe character.; Article →
Claudius Ptolemysky: A Greco-Roman scholar of Alexandria in the 2nd century CE, author of the Almagest and the Tetrabiblos. His Earth-centred model prevailed for centuries before modern astronomy replaced it.; Article →
Dashatradition: A Jyotish system dividing life into periods tied to different planets. The best known is Vimshottari dasha. In tradition each period is linked to the themes of its planet; here we offer them as prompts for reflection.; Article →
Eclipticsky: The Sun’s apparent yearly path among the stars. Both the ecliptic coordinate system used in astronomy and zodiac systems are built on it.; Article →
Enūma Anu Enliltradition: A major Babylonian series of tablets of celestial omens. In tradition, it collects thousands of interpretations of signs seen in the sky.; Article →
Five Elements (Wu Xing)tradition: A Chinese system of Wood, Fire, Earth, Metal and Water that complements the animal years. The elements describe cycles of change rather than physical substances.; Article →
Geocentric modelsky: An ancient view that Earth sits at the centre of the universe, with the Sun, Moon and planets circling it. We now know the planets orbit the Sun.
Hellenistic astrologytradition: A tradition that arose in Egypt and the Mediterranean after Alexander the Great, blending Babylonian, Greek and Egyptian ideas. Western astrology’s ascendant, houses and aspects descend from it.; Article →
History of astrologytradition: The story of how sky-watching in Mesopotamia, Greece, India and China grew into different symbolic traditions. For a long time astronomy and astrology went hand in hand, then parted ways.; Article →
Horoscopetradition: The Greek word originally meant “observer of the hour” and referred to the rising point of the ecliptic at a given moment. Today it means an astrological reading or chart.; Article →
Jyotishtradition: The Indian, or Vedic, astrological tradition; the name means “science of light.” It uses the sidereal zodiac and its own systems of periods and lunar mansions.; Article →
Lunisolar calendarsky: A calendar that follows both lunar phases and the solar year, occasionally adding a leap month. The traditional Chinese calendar is built this way.
MUL.APINsky: A Babylonian cuneiform compendium of stars, constellations and sky observations. It shows how ancient observers described the paths of the Sun, Moon and planets.
Nakshatratradition: In Jyotish, the 27 lunar mansions through which the Moon passes along the zodiac. Each has its own name and symbolic meaning in the tradition.; Article →
Precession of the equinoxessky: A slow wobble of Earth’s axis that shifts the equinox point among the stars. One full cycle takes about 26,000 years.; Article →
Rahu and Ketutradition: In Jyotish, the lunar nodes, treated as “shadow planets.” Astronomically they are the points where the Moon’s orbit crosses the ecliptic.; Article →
Sidereal zodiactradition: A system in which signs are measured against the fixed stars. It is used in Vedic astrology and currently differs from the tropical one by about 24°.; Article →
Tetrabiblostradition: Ptolemy’s four-book work setting out astrology as understood in his time. In tradition it is a foundational text, though not scientific evidence.; Article →
Tropical zodiactradition: A system in which Aries begins at the March equinox. It follows the seasons rather than the background stars and is the main one in Western astrology.; Article →
Zodiacsky: A band of sky around the ecliptic, the Sun’s apparent path, through which the Sun, Moon and planets travel. It is traditionally divided into 12 parts.; Article →

AI (26)

AI agentAI: An AI system that can carry out a series of steps on its own, such as opening websites and gathering information, to complete a task.; Article →
AI and sky observationAI: Astronomers use AI to sort large sets of images and data. Decisions and verification remain with human scientists.; Article →
AI assistantAI: A chat program that answers questions and helps with tasks in natural language. It is handy for ideas, but important things should be verified.; Article →
AI horoscopeAI: A horoscope in which artificial intelligence arranges and explains astrological symbols from the data you provide. It is a text for inspiration and reflection, not a prediction of fate.; Article →
AI translation of termsAI: Machine translation of astronomical and astrological concepts. It is useful, but terms should be double-checked because the same word can carry different meanings.; Article →
AI transparencyAI: Clarity about when a text was made with AI, where the data come from and what the limits are. This lets readers judge for themselves.; Article →
Artificial intelligence (AI)AI: Computer systems that perform tasks usually associated with human thinking, such as recognizing patterns or working with language. They are not people and do not understand the world the way we do.; Article →
Astronomy vs astrologysky: Astronomy is the science of celestial bodies and the Universe. Astrology is a cultural tradition that gives them symbolic meaning.; Article →
Birth datatradition: Date, time and place of birth, the basis for casting a natal chart. In astrological tradition, the exact time changes the ascendant and houses.; Article →
Calculation vs narrativeAI: Planetary positions are computed with mathematics, while interpretation is storytelling. Good practice is to take the calculation from ephemerides and let AI only explain.; Article →
Ephemeris (ephemerides)sky: Tables or data of calculated positions of celestial bodies over time. They underlie both astronomical sky maps and astrological calculations.; Article →
Ephemeris librarysky: A software package that calculates the positions of the Sun, Moon and planets for a given time using mathematical models.; Article →
Ethics of the AI horoscopeAI: Principles for honest, caring use: clearly labeling it as inspiration, giving no health, financial or fate-related advice, and respecting personal data.; Article →
Fact or readingAI: A fact can be checked with observations and sources. A reading is an interpretation within a tradition and offers a viewpoint, not a proven event.; Article →
Fact-checkingAI: Comparing claims against reliable sources such as NASA or ESA. It is especially important with AI answers.; Article →
Gaia (ESA star catalogue)sky: An ESA mission that measured the positions and motions of a huge number of stars. Its data help build accurate maps of the sky.; Article →
GEO (generative engine optimization)AI: Practices that make content clear and trustworthy so AI assistants can understand and cite it. It does not guarantee any result.; Article →
Hipparcos (catalogue)sky: An ESA space mission that measured stellar positions, a predecessor of Gaia.; Article →
Large language model (LLM)AI: A program trained on a vast amount of text that predicts likely next words and so builds answers. It can sound confident yet still be wrong.; Article →
llms.txtAI: A proposed plain-text file on a website that briefly describes its content for AI systems. It is not an official standard and not everyone uses it.; Article →
Model hallucinationAI: When an AI invents a fact, number or source that sounds convincing but is not true. That is why important claims should be checked.; Article →
Natal charttradition: A diagram of the sky at the moment and place of birth. In astrological tradition it is read as a symbolic picture for reflection, not a verdict.; Article →
Personal dataAI: Any information that can identify you, such as name, date, time and place of birth. Share it carefully and only when needed.; Article →
PromptAI: The question or instruction you type to an AI. The clearer and more specific it is, the more useful the answer tends to be.; Article →
schema.orgAI: A shared vocabulary of markup that websites use to describe their content in a machine-readable way, for example as an article, an event or a question.; Article →
Structured dataAI: Information organized in a clear, predictable format so computers can read it easily. It helps search engines and AI understand a page.; Article →

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