Help Calculating Aspects

If you're one of those lucky people who can quickly figure the aspects between two planets just by looking at the chart and mentally figuring the distance between 27 Aries 42 and 21 Leo 55 (a Trine), you won't need this page. For those of you who get a little confused, but want to learn how to calculate aspects rather than just relying on the Astrodienst aspectarian on the lower left margin of the horoscopes they provide, this info will hopefully help.

First, a few notes on aspects. An aspect is usually referred to as being exact if it is within one degree of being exact. The term for being precisely exact is partile. The orb of an aspect expressed in degrees is the allowable departure from partile that is used in defining the planets as being "in aspect." Personally, I like to use a lesser orb that many writers and computer programs. The closer an aspect is to being exact, the stronger it becomes. So aspects with a wide orb are often questionable and maybe not even noticeable. My recommendation for the allowable orb is a follows:

Sun and Moon (sometimes called the lights): conjunctions 8°, squares, trines, oppositions 7°, sextiles 5°

 

Planets: conjunctions 6°, squares, trines, oppositions 5°, sextiles 3°

 

The aspects that we will look for are just those formed by the Sun, the Moon, Mercury, Venus, Mars and Jupiter. When calculating the aspects, start with Sun and figure all of aspects that are formed by the Sun to the Moon, and to the slower moving planets. After you have calculated the aspects formed by the Sun, go next to fastest moving bodies. Remember, the aspects are formed by the fastest movers. Thus, it would be correct to say that Mercury formed an aspect to Uranus or Uranus received an aspect from Mercury, but it would not be correct to say the opposite, i.e. Uranus doesn't form an aspect with Mercury. The only exception to this is the Sun and Moon. The Moon is faster than the Sun, but we always say the Sun is forming an aspect with the Moon.

 

If you have trouble seeing where the planets are in relation to one another, it may help to plot them out on a 360° grid of sorts. The value in the second row is position that 0° of that sign in the zodiac:

 

 

By adding the degree of the planet placements in your horoscope and plotting them on to this grid, you may find it easier to calculate the precise aspects. Start with the planets in the order they are listed here.

 

© Michael McClain 1996-2012.  Permission is granted for unlimited noncommercial use.  All other rights reserved.