The parts of a chart, and what each one is worth.

Essays

• 01How to read the wheelA birth chart is a map of the sky from one place at one moment. Everything on it is a position, and every position is checkable.
• 02Why the birth time mattersA date fixes the planets. Only a time fixes the houses — and the difference is the whole chart.
• 03House systems, and why they disagreeTwelve houses, several incompatible ways of drawing them, and no consensus after two thousand years.
• 04Aspects and orbsThe angles between planets, and the honest question of how close is close enough.
• 05How these readings are madeThe interpretations on this site are composed from four vocabularies rather than written out one by one. Here is the whole method, so you can discount it accordingly.
• 06Moving one chart forward in timeThe natal chart is fixed at birth. Two older techniques move it forward — one by a strange arithmetic, the other by a real astronomical return — and they are not the same kind of claim.
• 07Making one chart out of twoSynastry compares two charts side by side. These two techniques go further and construct a single chart for the relationship itself — by two entirely different routes.
• 08Retrograde motionWhy planets appear to reverse, how often each one does it, and what a retrograde Mars can and cannot do in a chart.

Elements & modalities

The two ways the twelve divide — and, not coincidentally, the aspect system itself. Signs sharing an element sit 120° apart, a trine; signs sharing a modality sit 90° or 180° apart, a square or an opposition.

The twelve signs

Thirty degrees each, measured from the March equinox. Because the zodiac here is tropical it tracks the seasons, not the constellations — those have drifted roughly a sign in two thousand years.

The bodies

Thirteen points are plotted. Ten are planets (counting the Sun and Moon, as astrology does); three are calculated points rather than objects.

The twelve houses

Where the signs are a division of the sky, the houses are a division of the day — they depend on the birth time and the latitude, and rotate a full circle every twenty-four hours. They have their own threefold division too: angular, succedent and cadent stand to the houses exactly as cardinal, fixed and mutable stand to the signs, and for the same reason — the circle cut into three.

1. 1
   The Ascendantangular

   Bearing, appearance, the way you meet a room.

   Begins at the eastern horizon — the degree of the zodiac rising at the moment of birth. It moves a full circle every 24 hours, which is why the birth time matters more here than anywhere else.

2. 2
   Resourcessuccedent

   What you own, earn, and value.

   Follows the Ascendant counter-clockwise, below the horizon.

3. 3
   The near worldcadent

   Siblings, short journeys, speech, everyday learning.

   Still below the horizon, moving toward the lowest point of the chart.

4. 4
   The Imum Coeliangular

   Home, ancestry, the private base of a life.

   The lowest point of the chart — opposite the Midheaven, and the part of the sky beneath your feet at birth.

5. 5
   Playsuccedent

   Pleasure, romance, children, anything made for its own sake.

   Rising again toward the western horizon.

6. 6
   Work and healthcadent

   Daily labour, service, the body's maintenance.

   The last house below the horizon.

7. 7
   The Descendantangular

   Partnership, marriage, open enemies — the other person.

   The western horizon: the degree setting as the Ascendant rises. Always exactly opposite the first.

8. 8
   What is sharedsuccedent

   Other people's money, intimacy, death, inheritance.

   Above the horizon, climbing toward the meridian.

9. 9
   The far worldcadent

   Long journeys, foreign places, law, philosophy.

   The last house before the chart's highest point.

10. 10
    The Midheavenangular

    Vocation, reputation, what you are known for.

    The highest point the ecliptic reaches — where the Sun would stand at local noon. Independent of latitude, unlike the Ascendant.

11. 11
    The wider circlesuccedent

    Friends, allies, collective hopes.

    Descending from the meridian toward the eastern horizon.

12. 12
    What is hiddencadent

    Solitude, institutions, what works on you unseen.

    The last house, immediately above the Ascendant — rising next.

Aspects

The circle divided by small whole numbers. Orbs are the margin allowed before an aspect stops counting; every aspect on this site is listed with its own, so you can see how much is being claimed.

Configurations

Named shapes built from the aspects above. This site detects each one from raw longitudes on every chart it draws, states the orb it allowed, and — for the stellium — is explicit that a shared sign is a count, not a measured angle.

House systems

All of them agree on the Ascendant and Midheaven, which are astronomical facts. They disagree on how to divide the space between.

Rodden ratings

Lois Rodden's scale for how far a birth time can be trusted. Every entry in the catalogue carries one, and charts rated DD or X are drawn without houses or angles rather than pretending.