Astrology Basics: How Western Astrology Works
Western astrology reads the positions of the Sun, Moon and planets at a given moment against the twelve signs of the zodiac. A birth chart is that picture for the moment you were born; a horoscope compares it, or your Sun sign, with where the planets are today. Four ingredients do almost all the work: planets, signs, houses and aspects.
The four building blocks
Planets are what is happening: the Sun is identity, the Moon feelings, Mercury thinking, Venus love, Mars drive, and so on. Signs are how it happens: Venus in Aries loves differently from Venus in Taurus. Houses are where it happens: the twelve areas of life, from money to career. Aspects are the angles between planets, which show how the parts of a chart work together or pull against each other.
A sentence about a chart usually combines all four: Mars (drive) in Capricorn (patiently) in the 10th house (in your career) square the Moon (in tension with your need for comfort).
Sun sign astrology and chart astrology
The horoscopes in newspapers use only the Sun sign, which everyone born in the same month shares. They are a starting point. Chart astrology uses your date, time and place of birth to place all ten planets in their signs and houses, which is why two people with the same Sun sign can read as completely different.
Your Big 3 (Sun, Moon and rising sign) is the shortest useful summary of a chart. The rising sign and houses need an accurate birth time.
Tropical zodiac, real planets
Western astrology uses the tropical zodiac, which starts Aries at the March equinox, so the signs stay tied to the seasons. Vedic astrology uses the sidereal zodiac, tied to the background stars, which today sits about 24 degrees behind. Both use the real positions of the planets; they divide the sky differently.
What astrology is, and is not
The planetary positions are astronomy and can be checked. What they mean is interpretation from a long tradition. Astrology is a language for reflection and timing, not a science and not a substitute for medical, legal, financial or psychological advice.
Common questions
Where should a beginner start?
With your Big 3, then your full birth chart. Read your Sun, Moon and rising sign first, then look at the house each one sits in.
Do I need my birth time?
For the rising sign and houses, yes. Without it you still get every planet's sign, which is most of the chart.
Find yours
Cast your full chart in a minute: every planet's sign, house and aspects. Free birth chart
Read today's sky against your own chart
Everything on this page applies to your chart in a particular way. A Precision Horoscope casts your chart, finds today's transits to it and writes the reading for you. The first one is free. Get my free personal reading