Here you will be introduced to the geometry of your astrological houses, which are more significant to you as an individual than are the signs. Houses represent the Earth in a horoscope, which would otherwise merely be a diagram of the sky.

Imagine the Earth oriented in space so that you’re right on top. A large flat surface ("plane") balanced on top of the Earth right where you are is your horizon. As it extends out into space, some planets and stars are above your horizon plane, and some are below. Since we are millions of times further from the planets and billions to trillions of times further from the stars than we are from the center of the Earth, your horizon plane would intersect the same planets and stars if it passed through the Earth’s center. Where this relocated horizon plane intersects the path of the planets (ecliptic) to your east is your first house cusp, or Ascendant. Where it intersects the ecliptic to your west is your seventh house cusp, or Descendant.

At right angles to your horizon and passing through the North Pole and your Zenith is your Meridian plane. Where it intersects the ecliptic above you is your tenth house cusp, or Midheaven. Where it intersects the ecliptic beneath you is your fourth house cusp, or Nadir. These two planes intersect in your horizon’s north-south line and quarter the sky. Your horizon and meridian together with 4 more planes through that N-S line that trisect those quarters define the 12 astrology house cusps where they intersect the ecliptic.