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Genastro

Twelve lessons

Read a chart from the sky up

Astronomy first, meaning second. Each lesson is about 400 words, one idea per section, and every diagram is the real chart wheel drawing one chart.

Start with lesson 1 Glossary

Meet the example

Marta is invented. Her chart is not.

Marta is a fictional person, born on 14 March 1994, 06:42 in Lisbon, Portugal. The engine computed her chart from those facts, the same way it computes yours, and no position in these lessons is typed in. Her Sun is at 23°25′ Pisces and her Moon at 14°50′ Aries. The date was chosen because Lisbon ran on UTC+1 then, which lesson 10 puts to use.

Marta, 14 March 1994, 06:42, Lisbon, Portugal. Computed, not drawn.

The sky

What a chart measures: the horizon, the ecliptic and the four angles. Astronomy first.

  1. 1Start hereWhat a birth chart isA birth chart is a map of where the Sun, Moon and planets were in the sky at one moment, from one place.2 min read
  2. 2The horizon and the four anglesThe horizon splits the sky in two. Where the ecliptic meets it and the meridian gives the four angles.3 min read

The vocabulary

Signs, planets, houses and aspects, one idea per lesson, with the plain sentence behind each.

  1. 3The twelve signs: elements and modalitiesTwelve equal 30° slices of the zodiac, grouped by element and modality.2 min read
  2. 4The planetsWhat each body does in a chart, and the grammar that ties it to a sign: planets are verbs, signs are adverbs.2 min read
  3. 5Your Big ThreeSun sign, Moon sign and Ascendant: what each one is and how much of a chart they cover.2 min read
  4. 6The twelve housesTwelve areas of the chart, set by the birth place and time, so a birth clock matters.3 min read
  5. 7House systems: Placidus and Whole SignTwo ways to cut the sky into houses, where they agree and why they differ.2 min read
  6. 8AspectsThe angles between bodies, how an orb works, and which aspects the site counts.3 min read
  7. 9RetrogradesA planet that seems to move backward against the stars: why it happens and how the dates are computed.2 min read

How far to trust it

What a wrong clock does to a chart, what the zodiac is anchored to, and how the rarity figures are made.

  1. 10Why birth time and time zones matterThe Ascendant moves through a sign in about two hours, and clocks have changed over the years.2 min read
  2. 11Tropical and siderealTwo ways to fix the zodiac, and why most placements shift by one sign between them.2 min read
  3. 12How rare is a placementHow the frequency figures are simulated and how to read a rank and a percentage.2 min read

Reference