top of page
  • Writer's pictureWilliam Lamont - Astrology Blog

Why learn chart calculation?


I would like to give my thoughts on learning chart calculation, why should you understand something that is no longer required to draw up a chart. Below I give my personal view in point format of 6 reasons in no particular order of preference on why you should. All of the below subjects are brief explanations I am not explaining chart calculation or the process here. The below reasons make up part of calculating a chart and knowing how to calculate them and why brings a richness and depth to your astrological understanding that can’t be found using computer software.

Astrology blog, Time Zone Chart

1) Time zone’s and chart calculation

Pictures paint a thousand words they say, so when we look at how time zones are broken up into increments on a map using lines of longitude every 15 degrees. These longitude lines mark 1 hour of time from Greenwich in either an easterly or westerly direction, it gives a thorough perspective on the vast amount of different time zones and also there various and surprising geography. The Ascendant or Suns rising point moves 1 degree of longitude every 4 minutes and if calculated you will realise after 15 degrees this equates to one Earth hour and is why time zones are calculated like this and is caused by the Earth's primary motion. Because it is of such importance for a correct time in a natal chart or election chart etc, a deeper understanding of how and where time zones are affected is critical in finding or avoiding errors in charts.

2) Hemispheres and chart calculation

When we look at a Natal chart, we must realise that not everyone lives in the same hemisphere, so it’s important to realise in the northern hemisphere where most of the population lives the Sun is predominantly to the south towards the equator or more precisely the ecliptic on a 23 degree slant. So, the top of a natal chart indicating the day sect is the South. However, in the Southern hemisphere the Sun is predominantly in the north sky towards the equator or more precisely the ecliptic again. So, when we look at a natal chart for someone born in let’s say New Zealand the top of the chart or day sect is the north not the south. This is extremely important to understand for Horary, Natal or Electional astrology for instance.

3) Declination and chart calculation

While calculating a chart one of the processes is to calculate the declination of the planets. This is the degree north or south of the ecliptic and brings an awareness to the position of particular planets that may be beyond 23.5 degree south or north of the ecliptic, and is known by many as the term out of bounds. Chart calculation also explains the astronomy of declination, parallels and contra parallels which are all aspects of declination and are also useful in the delineation of charts, all of these are useful in judging the potency of planets in particular.

Astrology blog, Natal Chart

4) Directions and chart calculation

In the course of learning chart calculation we gather astronomical information that can benefit our understanding of nature and why the sky appears the way it does. The primary and secondary motions of the Earth are at the core of this. Primary motion being the Earths rotation on its own axis, and secondary motion being that of its rotation along the solar ecliptic around the Sun. This gives an understanding of why the Stars rise and set the way they do and makes astronomical observations easier. Along with the understanding of declination, hemispheres and the ecliptic plane being 23.5 degrees we can observe the wandering planets and find their location easier by narrowing our possible area to scan in the night sky.

5) Speed and chart calculation

While calculating a natal chart, solar arc or progression we are constantly going to the ephemeris to find the midnight hour daily planet positions, as well as the positions of the midheaven and ascendant. Then using logarithms, we calculate more accurate positions and by doing this we attain an understanding of the speed of the angles, cusps planets and lights. This is most useful in delineation as simply looking at a chart and seeing what planets are retrograde or moving forward is easy but understanding the nuances like a slow Mercury or Moon may give a different perspective that is not always obvious. This will have you using your ephemeris at every opportunity once you fully understand the comparative speed variations.

6) Our Predecessors and chart calculation

Astrologers are not people who just look at charts and make statements of probability printed in your favourite magazine or splashed across a novelty website. We need to understand our predecessors before us were Mathematicians, Astronomers, Philosophers, Advisers, Physicians, Alchemists, Poets and students of Nature. If not all they were certainly most of the above and to these wise folk they gave one name, they were to be known as Astrologers. For to be an Astrologer is to be well rounded and versed in many disciplines and two of those disciplines are encompassed in chart calculation in mathematics and Astronomy.

Conclusion on chart calculation

Astrology is ruled by Uranus the planet of mechanism, and like when a good driver understands how his car works, and is able to avoid mishaps, breakdowns and improve performance, a good Astrologer must understand the mechanics of his craft, for the same reasons.

Astrology blog written by William Lamont Bellingen astrologer Australia on the astrology of chart calculation.

bottom of page