Basic Astronomy · 13🆓 Free preview Paid course Unlocked

House Systems: Why Whole Sign, Equal, and Quadrant Houses Change Placements

4 min read

Learning objectives

✦Explain why several house systems exist, since dividing a spherical sky into twelve parts has no unique solution
✦Distinguish whole sign, equal house, and quadrant systems such as Placidus
✦Explain why quadrant houses become distorted at high latitudes and why changing systems changes planetary houses

Enter the same birth details into two chart websites, and one places a planet in the 2nd house while the other puts it in the 3rd. It may look like a malfunction, but both calculations can be correct. They simply use different house systems.

This is a common stumbling block that often goes unexplained. The twelve houses lesson introduces their life areas, while ASC–DSC and MC–IC explain the four angles. Here we ask how the twelve house boundaries are actually drawn.

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This lesson is part of the “Natal Astrology” series. Purchase the series to unlock all lessons and receive 1000 AI credits.

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