Astrology and Horoscopes

Astronomy For Astrologers

Welcome to the Astronomy for Astrologers Section of!

A series of articles demonstrating the basic astronomical principles behind certain astrological phenomenon. To fully understand Astrology, the Astrologer needs to have at least a fundamental understanding of Astronomy but often the maths and lack of three dimensional diagrams and tools make it difficult to grasp.


The Astronomy of Astrology

Astrology is based on astronomical principles. Until around 3 centuries ago there was not a very clear distinction between astronomy and astrology. For example, Ptomley, the great astrological synthesist of the ancient world, wrote books on both astrology and astronomy.

Earth movement around the SunThe ancient astrologer needed to be an expert astronomer, observing the heavens, to get the data s/he needed. It has been argued that modern astronomy is the child of ancient astrology and, without the astrological focus of astronomy in the past, astronomy could never have advanced as far as it has today. Fortunately for astrologers today, there is no need to regularly observe the heavens, as in ancient times. Essential astronomical data, as utilised by astrologers, is easily obtainable in the form of printed works, or from astrological computer programs.

The major philosophical difference between the perspective of astronomers and astrologers today is this: Astronomers largely view astronomical phenomena as having little bearing on the psyche of living organisms. (There are exceptions, but these are still a minority). Astrologers largely view astronomical phenomena as having an all pervasive relationship to the psyche of living organisms and terrestrial occurrences. Astronomers generally view the heavens as to be expressive of physical and mathematical principles only. Astrologers see the heavens as also reflecting spiritual principles.

Astrology is largely centered in the observation of the solar system. This system encompasses the immediate cosmic environment in which we live. The solar system is a complete unit – a whole. The Sun binds and ties together the family of planets, as all the planets revolve around the Sun. As such, from the earth perspective, the solar system represents the next highest level of energy to the unit which is the earth (as the solar system contains the earth energy). As a whole, the solar system may be regarded as being a miniature universe. The planets, Sun and Moon act as filters or receptors for universal energies.

Most astrologers use a geocentric model of the solar system. This means they consider the Sun, Moon and planets as if they revolved around the earth (which is what they appear to do). In contrast, astrologers who use a heliocentric model of the solar system view the planets as they actually revolve around the Sun.

The reason for taking the geocentric position is simple. We live on the earth. As the earth is our base, this must be the center from which we view the heavens. The astronomical data is interpreted from the earth perspective – as we are viewing the influence of astronomical bodies on the earth. This is the rationale behind the geocentric model. (On the other hand, strictly speaking, heliocentric astrologers are viewing the influence of astronomical bodies on the Sun. Although they too reinterpret such data as if from an earth perspective).

There are other reasons for using the geocentric model. After all, this is the model which accurately matches our seasons. Another reason is a purely experiential one. Experience and millennia of observation has proven that the geocentric or earth based view of the heavens works. This is particularly for the understanding of the human psyche. (Interestingly, heliocentric astrology/astronomy has been shown to work well for the prediction of weather patterns on the earth. The radio astronomer John Nelson made many accurate weather forecasts based on the heliocentric model).

What do Astrologers Know of Astronomy?

As the scientific community has pulled away from historic Astrological analogies and methodologies, the fact still remains that astronomy’s ancestral line is rooted in Astrology. Even today, the worlds top scientists and physicians are learning to swallow the bitter pill that there may be some truth in Astrology.

The magic of Astrology is in its symbolism and although there are differing methods of Astrology, and yes even astrologers argue its true nature, it provides an insight into our human condition that the rigid structures of science cannot achieve. These ancient astrological methods were understood in depth by our ancestors and are only beginning to be fathomed by modern science.

In order to become a good astrologer, you must have an understanding of planetary movement, how to map the stars and planets in the skies. The efforts of great observers like Tycho Brahe in the late 16th century who’s charting of planetary movements paved the way for for the theorist Johannes Kepler to provide the world with his laws of planetary motion, telling us that the planets move in an elliptical orbit around the sun at a calculable speed, have allowed us the capacity to plot the movement of the heavens.

The diagram above shows the apparent movement of the sun around the earth as seen from the earth. The path of the sun is called the “ecliptic”. Around the ecliptic are the twelve constellations of the zodiac, so that at any point through one calendar year the sun will be “in” one of the signs of the zodiac as it travels around the earth. When the sun reaches its highest point on the ecliptic above the celestial equator, this is called “Summer Solstice“, from which the “Tropic of Cancer” line of latitude can be drawn, as this is where the sun moves into Cancer. The opposite of this is when the sun reaches its lowest point on the ecliptic “Winter Solstice“, from which the “Tropic of Capricorn” line of latitude can be drawn, as this is when the sun moves in to Capricorn.

As in the case of the sun, all of the other planets in our solar system travel around the ecliptic so that at any given point in time each planet will also be “in” one of the signs of the zodiac allowing the astrologer to interpret their influence. Each planet will also rise and fall above and below the line of the ecliptic by a few degrees as if they are wobbling up and down as they appear to travel around the earth. *

Using the diagram above you can also see the celestial equator being used as a reference for plotting the position of the sun at summer solstice. This co-ordinate system is called the Equatorial System. At summer solstice the sun is at 6hours Right Ascension and 23.5 degrees Declination. To understand this imagine you are stood in a room facing a door. Hold out your arm to point at the door directly in front of you. Let’s say that this is 0 hours right ascension, now turn your whole body 90 degrees to your left keeping your arm straight so that you are now pointing at a window. The window is 6 hours Right ascension from the door. This is true because 6 hours is a quarter of 24 hours (1 day) as is 90 degrees a quarter of 360 degrees (A full circle). Got it!?

If you now raise your arm to point at the curtain rail above the window the angle you have raised your arm is the angle of declination 0 to 90 degrees North and 0 to 90 degrees south. Using this system you can plot any item in the room using 2 co-ordinates of right ascension and declination. In the equatorial system 0 degrees right ascension is at 0 degrees Aries (Where the sun moves into Aries and the ecliptic bisects the celestial equator) otherwise known as the Vernal Equinox.

* The co-ordinate system used predominantly by Astrologers is the ecliptic system where the suns ecliptic is used as the x-axis where the degrees of the signs of the zodiac are used as points of reference as the planets move through them. This co-ordinate is called Celestial Longitude, and the planetary wobble I mentioned earlier where the planets move above and below the ecliptic is called Celestial Latitude.