Imagine the sky at the very moment you were born, a great wheel extending outward in every direction above and below the horizon. Now imagine if this were divided into twelve sections extending outward from the Earth, starting with the sign of the Zodiac rising upon the Eastern Horizon when you were born. Each of these twelve sections is the house, and they represent different aspects of your life. Every planet, as well as the two luminaries, namely the Sun and Moon, are positioned in one of these sections. Which house they are located within depends upon the moment of your birth, and some of your houses may contain multiple planets or even none at all.
Each of these houses is associated with sets of traits that start with your own self and extend outward into society. Every time that a planet visits a house, it energizes the traits within that house. This allows astrologers to use these houses in order to predict the parts of your life that will come into focus to help you find the best places to take action. This makes it critical to have an accurate system for calculating and understanding the house divisions. Unfortunately, it isn’t always so easy because there are several ways to calculate these divisions.
While we are discussing wheels, it is important to keep in mind that the wheel of houses is very different from the wheel of the zodiac. While the zodiac wheel is determined by the apparent motion of the Sun around the Earth as it progresses through its yearly transit, the wheel of houses is based upon the daily rotation of the Earth upon its own axis.
The Different House Systems
The houses are not astronomically fixed, and modern astrologers make use of many different methods for dividing them. These different methods stem from widespread disagreement over how the houses should be divided as well as which fundamental plane should be the object of the initial division. Though we cannot look at all of the many different house systems, let’s look at three of the most popular choices. These are Porphyry, Whole Sign, and Placidus House Systems.
Porphyry
With the Porphyry system, the quadrants of the ecliptic are each divided into three equally sized parts located between its four angles. This is an old and fairly simple to calculate system that is regaining some traction among astrologers. Using this system at the moment of birth, the MC (where the highest point of the Sun’s path through the ecliptic meets the meridian) is found as well as the degree of the Ascendant which is the sign rising upon the Eastern Horizon.
The cusp of the 10th house is found by taking the degree of the sign that corresponds with the MC, and the cusp of the 1st house is marked by the degree of the Ascendant. From here, the remaining space between these two is separated into three equal segments.
In this system, the chart’s angles, particularly the Ascendant, Descendant, MC, and IC, are prioritized and used as a way to determine the houses. A great many astrologers value these angles, particularly the MC, or midheaven. For this reason, a number choose this system, including most Indian astrologers.
Whole Sign
The Whole Sign system, also known as the Sign-House system, is the earliest system for measuring houses. It remained as a primary method for determining houses for very nearly a millennia, but by around the twentieth century, it had fallen out of popularity in the Western tradition.
With the Whole Sign system, all houses are equally sized at 30°, and the sign of the zodiac containing the Ascendant will be the 1st house. The following sign will be the second house, and the pattern continues this way.
The Whole Sign system is very easy to calculate and understand, but more complex phenomena, including intercepted signs, are unable to occur in this system. Regardless, this system is still popular and easy to use.
Placidus
Placidus is far and away the most popular house system in use today and is based on time rather than space in determining houses. This method has roots extending far back into antiquity and gained popularity in the Renaissance under its namesake Placidus de Titis.
This method works by setting the cusps of the houses to two-hour increments from the moment of your birth. The cusp of the 1st house is the degree of the zodiac sign, which is rising upon the Eastern Horizon at the moment of your birth. About two hours later, measurements are made again in order to see where this degree is now, and that will become the cusp of the 12th house. This proceeds through the course of twelve hours until the 7th house has been set. Using the angles of these six houses, the other six houses will be set.
As you can see, using this method, each house will be sized according to the amount of time it spends on the Earth’s horizon, and this typically results in houses of vastly different sizes. Near the poles, the system does not work at all due to certain degrees never touching the horizon.
Final Thoughts
As you can see, there are several ways to calculate your house system, and if you would like to see your own natal birth chart, you can now customize any Ephemeris birth chart talisman or necklace to any of these three house systems, as well as others. All you need to know is the location and time of your birth to get started and click down into the Advance section to choose your house system. Not only is it a beautiful representation of your natal chart. It is also a great gift or a wonderful way to celebrate your sign pride.