Like a wheel, dials are a way of viewing an astrology chart.
A chart wheel displays the zodiac around a circle (called a wheel) and this circle is divided into 360 degrees (of ecliptic longitude).
The wheel is also grouped into 12 equal sized contiguous groups, called zodiac signs (Aries, Taurus, Gemini etc), each sign being a 30 degree section of the wheel. An example is below, with the beginning of the zodiac (0 Aries) placed in the middle of the wheel on the left, and the remaining signs follow on in 30 degree sections from there.
![]() The 360 degree chart wheel |
Then, according to where planets are positioned in the sky at the time of the chart, they are placed in the chart wheel at the corresponding degree of the zodiac.
![]() THe 360 degree chart wheel - with planets |
With the planets in their respective positions around the zodiac we can then measure the shortest longitudinal arc between them, i.e. measure how many zodiac degrees they are apart from each other along the shortest route around the wheel between them. As is commonly known, certain amounts of degrees between the planets are identified as "aspects", each aspect having a name. The main aspects are below:
0 degrees (same position) is called a Conjunction ß
30 is called a Semisextile •
45 a Semisquare “
60 a Sextile ’
90 a Square ‘
120 a Trine á
135 a Sesquiquadrate ”
150 a Quincunx (or inconjuction) –
180 an Opposition à
When the degrees that two planets are apart, on the section of the wheel where they are closest together, comes exactly (or close) to one of the above listed amounts, we say there is an "aspect" between the two planets. We usually also draw a line between those two planets in the chart wheel so we can see this aspect visually. Initially it may not be easy to see what aspect each line refers to, but with color coding and familiarity it soon becomes more obvious. Below is an example where the aspects have been represented by colored lines between the two planets in question:
![]() The 360 degree chart wheel (1st Harmonic) - with all planetary aspects |
However another way of viewing these aspects is by using a Dial. A key purpose of Dials is to make seeing aspects between the planets easier than it is in a chart wheel, which it often does. But at a minimum it is an alternative way of viewing aspects. Another key purpose of a Dial is to easily see midpoints, which for the majority of midpoints is often difficult to do in a wheel.
A midpoint is the point which is longitudinally in the middle of two planets on the section of the chart wheel where the planets are closest. So if an aspect also exists between two planets, then the midpoint will be midway along the aspect (line) between them.
The basic underlying principle of the Dial is that of harmonics. Let's return to the aspects listed above to understand what harmonics are.
Harmonics are essentially "harmonies", like in music, which are themselves different resonating vibrations, or resonances. Each musical tone that makes up the harmony is vibrating at a different resonance. And all the aspects in astrology are based on harmonics. As such it is really harmonics that are allowing us to see the patterns (initially shown by the aspects) in an astrology chart.
When we divide a circle up into equal parts, each divided part has a different tone (or resonance) to that of the original whole circle, and in this way with each division of the circle we are creating the different harmonics. It is therefore the denominator (what we are dividing the circle by) that signifies the harmonic.
Harmonics are therefore represented by whole numbers, starting with the number 1. However if we divide the circle by 1 we are not dividing it up at all, as the result is still the whole circle. Thus the 360 degree chart wheel as we normally use it is already functioning in the 1st harmonic.
Within a human being the facet of the life force (that each planet represents) operates according to its own energy, fulfilling a certain function. In a normal 360 degree chart wheel, one or more planets directly connect with each other when they are separated by an aspect (a certain amount of degrees apart on the chart wheel, as listed above). And each aspect involved in these connections is of a certain harmonic.
In the 360 degree chart wheel functioning in the initial harmonic of 1, the primary initial aspect based on that harmonic is the Conjunction. Planets in a conjunction are all in the same (single, 1) place on the chart wheel, and thus the harmonic the conjunction resonates to is the harmonic of 1. In other words the 360 degree wheel is divided by the harmonic of 1, giving us the conjunction aspect. Further harmonics after 1 produce the remaining aspects we use in the chart.
With the harmonic of 2 we divide the 360 degree wheel into 2 equal parts, giving us an aspect of 180 degrees (360 / 2 = 180), which is the aspect of an Opposition. 2 oppositions joined contiguously together circumscribe the whole 360 degree wheel. Below it appears as if there is only one opposition going from 0 degrees to 180 degrees. However that same opposition can also be read as going from 180 degrees back round to 360 degrees, or 0 degrees in other words, as well.
![]() The 2nd Harmonic - Oppositions |
With the harmonic of 3 we divide the 360 degree wheel into 3 equal parts, giving us an aspect of 120 degrees (360 / 3 = 120), which is the aspect of a Trine. 3 trines joined contiguously together circumscribe the whole 360 degree wheel.
![]() The 3rd Harmonic - Trines |
With the harmonic of 4 we divide the 360 degree wheel into 4 equal parts, giving us an aspect of 90 degrees (360 / 4 = 90), which is the aspect of a Square. 3 squares joined contiguously together circumscribe the whole 360 degree wheel.
![]() The 4th Harmonic - Squares |
When 2 squares (90 degrees each) are added together they come to 180 degrees (an opposition). The midpoint of the two ends of an opposition is the point on the opposition aspect where these two squares (each half an opposition) meet and join together. Below Mercury and Saturn are in an opposition (180 degree aspect). The midpoint of Mercury and Saturn is exactly mid-way between them, and below Jupiter is sitting on that mid-way point, so is exactly conjunct the midpoint of Mercury and Saturn.
Because that midpoint degree is half of an opposition (180 / 2 = 90) there is also a square aspect between Jupiter and Mercury on one end of the opposition, and also a square aspect between Jupiter and Saturn on the other end of the opposition. This is how harmonics work: the harmonic of 2, when then multiplied by 2, equals 4; which is the harmonic of the square aspect. So an opposition contains within itself two squares.
![]() The 4th Harmonic - the 2nd harmonic midpoint |
With the harmonic of 5 we divide the 360 degree wheel into 5 equal parts, giving us an aspect of 72 degrees (360 / 5 = 72), which is the aspect of a Quintile. 5 quintiles joined contiguously together circumscribe the whole 360 degree wheel. A quintile is not usually regarded as a main aspect, although it is often included in a chart.
With the harmonic of 6 we divide the 360 degree wheel into 6 equal parts, giving us an aspect of 60 degrees (360 / 6 = 60), which is the aspect of a Sextile. 6 sextiles joined contiguously together circumscribe the whole 360 degree wheel.
![]() The 6th Harmonic - Sextiles |
Because a sextile is 60 degrees, two sextiles added contiguously together makes a trine (120 degrees). In this vein we can see below that Mars, sextile Mercury and sextile Uranus, is also on the midpoint between Mercury and Uranus.
![]() The 6th Harmonic - the 3rd harmonic midpoint |
With the harmonic of 7 we divide the 360 degree wheel into 7 equal parts, giving us an aspect of 51 degrees & 26 minutes (360 / 7 = 51.42), which is the aspect of a Septile. 7 septiles joined contiguously together circumscribe the whole 360 degree wheel. A septile is not regarded as a main aspect, although it is sometimes included in a chart.
With the harmonic of 8 we divide the 360 degree wheel into 8 equal parts, giving us an aspect of 45 degrees (360 / 8 = 45), which is the aspect of a Semisquare. 8 semisquares joined contiguously together circumscribe the whole 360 degree wheel.
![]() The 8th Harmonic - Semisquares |
Because a semisquare is 45 degrees, two semisquares added contiguously together makes a square (90 degrees). in this vein we can see below that Venus, semisquare Mercury and semisquare Jupiter, is also on the midpoint between Mercury and Jupiter, which are in a square aspect with each other.
Likewise Jupiter, semisquare Venus and semisquare Pluto is also on the midpoint between Venus and Pluto, which are in a square aspect with each other. Additionally Jupiter, which is square Mercury and square Saturn as well, is therefore also on the midpoint between Mercury and Saturn, which are in an opposition aspect with each other. In this situation Jupiter is at the midpoint of two different pairs of planets, which is giving it an increased significance in the chart.
Finally Pluto, semisquare Jupiter and semisquare Saturn, is also on the midpoint between Jupiter and Saturn, which are in a square aspect with each other.
Additionally, with a semisquare being 45 degrees, three semisquares added contiguously together makes a Sesquiquadrate (135 degrees), which is shown between Mercury and Pluto. The midway point between these two planets, i.e. the midpoint between them, is where the "X" is drawn. Unlike all the previous examples there is no planet on that point, at the midpoint (the midway point between Mercury and Pluto on the side of the chart wheel where they are closest together). But that doesn't mean the midpoint doesn't exist - it does. Midpoints stand on their own whether there are planets on them on or not.
Obviously there will always be a lot of midpoints in a chart (one between every possible pairing of planets/points), so in terms of the big picture when delineating an astrology chart, often they are a secondary consideration to aspects. They are usually more subtle, but not necessarily always less significant - they are sensitive points that can be correlated to factors related to the planets they are midpoints to.
In this example when any planet transits over the point where "X" is drawn it will have an impact on the functioning of Mercury and Pluto, over and above the affect of Mercury and Pluto being in a sesquiquadrate aspect with each other already has. A Gemini/3rd house influence will be added to the mix, along with the influence the transiting planet normally has (according to its inherent nature).
What we can see here is that the 8th harmonic contains all the other aspects that are a simple multiple of it:
45 x 1 = 45 (8th harmonic, semisquares)
45 x 2 = 90 (4th harmonic, squares)
45 x 3 = 135 (8th harmonic, sesquiquadrates)
45 x 4 = 180 (2nd harmonic, oppositions)
![]() The 8th Harmonic - the 4th and 2nd harmonic midpoint |
With the harmonic of 9 we divide the 360 degree wheel into 9 equal parts, giving us an aspect of 40 degrees (360 / 9 = 40), which is the aspect of a Novile. 9 noviles joined contiguously together circumscribe the whole 360 degree wheel. A novile is not regarded as a main aspect, although it is sometimes included in a chart.
With the harmonic of 10 we divide the 360 degree wheel into 10 equal parts, giving us an aspect of 36 degrees (360 / 10 = 36), which is the aspect of a Decile. 10 deciles joined contiguously together circumscribe the whole 360 degree wheel. A decile is not a main aspect, and is rarely included in a chart.
With the harmonic of 11 we divide the 360 degree wheel into 11 equal parts, giving us an aspect of 32 degrees and 44 minutes (360 / 11 = 32.73), which is the aspect of a Unidecile. 11 unideciles joined contiguously together circumscribe the whole 360 degree wheel. A unidecile is not a main aspect, and is rarely included in a chart.
With the harmonic of 12 we divide the 360 degree wheel into 12 equal parts, giving us an aspect of 30 degrees (360 / 12 = 30), which is the aspect of a Semisextile. 12 semisextiles joined contiguously together circumscribe the whole 360 degree wheel.
![]() Sextile |
Because a semisextile is 30 degrees, two semisextiles added contiguously together makes a sextile (60 degrees). in this vein we can see below that the Sun, semisquare Mercury and semisquare Jupiter, is also on the midpoint between Mercury and Jupiter, which are in a square aspect with each other.
Likewise Jupiter, semisquare the Sun and semisquare Pluto is also on the midpoint between the Sun and Pluto, which are in a square aspect with each other. Additionally Jupiter, which is additionally square Mercury and square Saturn, is therefore also on the midpoint between Mercury and Saturn too, which are in an opposition aspect with each other. In this situation Jupiter is at the midpoint of two different pairs of planets, which is giving it an increased significance in the chart.
Finally Pluto, semisquare Jupiter and semisquare Saturn, is also on the midpoint between Jupiter and Saturn, which are in a square aspect with each other.
As well, with a semisquare being 45 degrees, three semisquares added contiguously together makes a Sesquiquadrate (135 degrees), which is shown between Mercury and Pluto. The midway point between these two planets, i.e. the midpoint between them, is where the "X" is drawn. Unlike all the previous examples there is no planet on that point, at the midpoint (the midway point between Mercury and Pluto on the side of the chart wheel where they are closest together). But that doesn't mean the midpoint doesn't exist, it does. Midpoints stand on their own whether there are planets on them on or not.
Obviously there will always be a lot of midpoints in a chart (one between every possible pairing of planets/points), so in terms of the big picture when delineating an astrology chart, often they are a secondary consideration to aspects. They are usually more subtle, but not necessarily always less significant - they are sensitive points that can be correlated to factors related to the planets they are midpoints to.
In this example when any planet transits over the point where "X" is drawn it will have an impact on the functioning of Mercury and Pluto, over and above the affect of Mercury and Pluto being in a sesquiquadrate aspect with each other already has. A Gemini/3rd house influence will be added to the mix, along with the influence the transiting planet normally has (according to its inherent nature).
What we can see here is that the 8th harmonic contains all the other aspects that are a simple multiple of it:
45 x 1 = 45 (8th harmonic, semisquares)
45 x 2 = 90 (4th harmonic, squares)
45 x 3 = 135 (8th harmonic, sesquiquadrates)
45 x 4 = 180 (2nd harmonic, oppositions)