Birth Chart Basics
The four angles are the ascendant on the eastern horizon, the descendant opposite it on the western, the midheaven at the top of the chart and the imum coeli at the bottom. They are the only parts...
Stand outside at the moment of your birth and look east. The point of the ecliptic rising over the horizon is your ascendant. Directly behind you, setting in the west, is the descendant. Straight overhead, or as near as the ecliptic gets, is the midheaven. Beneath your feet, on the other side of the Earth, is the imum coeli.
They are not planets and not fixed points of the zodiac. They are directions, relative to where you were standing, and that is exactly why they are the most personal thing in a chart.
The ascendant is how you come across and how you start. The descendant, opposite it, is what you look for in other people and what you meet in partnership. The midheaven is your public role, your reputation and what you are known for. The imum coeli is home, family and the private base everything else rests on.
Two axes, then: self against other, and public against private. Those two lines are the structural skeleton of a chart.
The Earth turns once a day, so the entire zodiac appears to rotate past the horizon once every twenty-four hours. That is one degree every four minutes and a whole sign every two hours. No other part of a chart moves anything like that quickly, and it is why a birth time matters more than anything else you can supply.
| Angle | Where | What it covers | Also called |
|---|---|---|---|
| Ascendant | Eastern horizon | How you come across, how you start | Rising sign, AC |
| Descendant | Western horizon | Partnership, what you look for in others | DC |
| Midheaven | Top of the chart | Career, reputation, public role | MC, medium coeli |
| Imum coeli | Bottom of the chart | Home, family, private foundations | IC |
In the two hours either side of your birth, the Moon moved about one degree and the Sun moved about five minutes of arc. In that same two hours the ascendant moved through an entire sign, roughly thirty degrees, and took all twelve houses with it.
That ratio is the whole argument for birth times. A chart calculated an hour out has almost all the planets right and the entire structure wrong, which is the worst kind of error because the chart still looks plausible.
the Big Three, then your chart ruler, then how to find your birth time.
Everything on this page is general by necessity. A reading built from your own date, time and place is the version that names your placements rather than describing the categories they fall into. If you do not know your birth time, this covers how to find it.
The ascendant, descendant, midheaven and imum coeli.
Because they are set by the Earth's rotation, which moves them a degree every four minutes.
The ascendant, because it sets the entire house system that everything else is read against.
RubyAstro writes about astrology for reflection and self-understanding. Nothing here is medical, legal or financial advice, and none of it is a prediction of events. Read our full disclaimer.
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