← Encyclopedia of Astrology · lesson 5/235
Horizon
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What it is
The horizon is the line where the sky seems to meet the ground: everything above it is visible, everything below it hidden by the Earth. In astrology it is treated as a great circle around the observer — the rational or astronomical horizon, a plane through the centre of the Earth parallel to the ground — rather than the uneven line of hills and rooftops you actually see, which deVore calls the sensible horizon.
Because it depends on where you stand, the horizon is what makes a chart local. Two people born at the same moment in London and in Sydney share the same planets in the same signs, but not the same horizon, so not the same Ascendant, houses or angles.
What it gives a chart
The horizon cuts the ecliptic at two points, and those two points are among the most important in astrology:
- the eastern point, where signs and planets are rising, is the Ascendant — the cusp of the first house in most systems;
- the western point, where they are setting, is the Descendant — the cusp of the seventh house.
On the chart wheel the horizon is the horizontal line through the middle. The half of the wheel above it (the seventh to the twelfth houses) is the sky above the Earth; the half below (the first to the sixth) is the sky beneath it. The meridian crosses it at right angles, and between them the two great circles mark the four angles.
How it is read
- Rising and setting. A planet close to the Ascendant has just risen and is read as prominent, closely tied to the person's manner and body. A planet near the Descendant is setting, and tends to be read through other people and partnerships.
- Above and below. Many astrologers read a chart with most planets above the horizon as more outward-facing, public or other-oriented, and one with most below as more private or inward. This is a broad tendency, not a rule.
- Day and night. Whether the Sun is above or below the horizon decides whether a chart is diurnal or nocturnal — its sect. Sect in turn decides which planets the tradition treats as most helpful or most difficult, and which triplicity rulers take the lead.
- Hours. The time between sunrise and sunset, divided into twelve, gives the unequal planetary hours.
Latitude and rising times
The tilt between the horizon and the ecliptic changes with latitude and through the day. Some signs therefore rise quickly and others slowly — the signs "of short" and "of long ascension" — and in temperate and northern latitudes the houses can be very unequal in size. Far enough north or south, some degrees of the zodiac never rise at all for part of the year, and several house systems break down there. This is one reason whole-sign houses and equal houses are sometimes preferred for births near the poles.
In the tradition
Hellenistic astrologers called the rising sign the hōroskopos, "the hour-marker" — the source of our word horoscope. Lilly gave a planet in the first house, as in the tenth, his highest score for house position: a planet on the horizon or the meridian was, for him, a planet able to act.
In a reading here
On the chart wheels here the Ascendant is pinned to the left (nine o'clock), so the horizon runs straight across the wheel.