The sign positions of the luminaries and inner planets contribute to the personality in immediate and obvious ways. But the sign positions alone of the social planets (Jupiter and Saturn) are of less importance in defining the individual, and those of the outer planets are irrelevant. (Having said that, there are situations in which the sign position of social and outer planets becomes relevant, and such situation is when they are in aspect to a luminary or inner planet.)
While sign positions are integral to figuring out what you are made of, they are only one part of the story. There is another significant part, which is that of planets interacting or engaging with each other, like actors in a play. This engagement is called an aspect. The nature of the engagement–whether it is joining forces, or being at odds with one another, or indulging in healthy competition–depends on the kind of aspect between planets.
Aspects are where the social and outer planets really come out to play. The aspects of these planets to the luminaries and inner planets are of profound importance in shaping the life. For instance, you could get a decent read on someone from knowing that their Sun is in Cancer, and Moon is in Sagittarius. But, if you also see that there is an aspect between Pluto and the Moon, you would be adding a game-changing factor to your interpretation of the life expression.
Various types of aspects are used in horoscope analysis. The most important of them, the so-called Ptolemaic aspects, are the conjunction (when the planets are next to each other), opposition (when the planets are across, or 180 degrees, from each other), square (90 degrees apart), trine (120 degrees apart), and sextile (60 degrees apart). Every one of these aspects signifies how the participating planets combine their energies in life expression, and the result is different based on the kind of aspect.
Setting aside the actual meanings of the aspects (I will write about the detailed expressions of individual aspects in other posts), it stands to reason that two planets in trine to each other would have a different kind of synergy than the same two planets in square to each other. However, even the expression of a particular kind of aspect–trine, square, or any other–would be different depending on the actual planets involved. For example, a conjunction of the Sun and Saturn would have a markedly different manifestation than a conjunction of the Sun and Jupiter, since the nature of Saturn is different from the nature of Jupiter. And an aspect between Mercury and Venus would be substantially different in expression than the same aspect between Mercury and Uranus.
Here are some examples of planetary positions, and the corresponding aspects between them. (I haven’t shown the actual planets because I only want to focus on the degree separation and the aspect.) The last column, orb, is the offset from the exact degree separation defined for that aspect. (For an explanation of positions and how to read them, see the post on Ephemeris.)
| Planet 1 | Planet 2 | Aspect | Orb |
|---|---|---|---|
| Can 12o15‘ | Sco 10o03‘ | Trine | 2o12‘ |
| Tau 03o23‘ | Tau 07o15‘ | Conjunction | 3o52‘ |
| Ari 23o15‘ | Lib 24o20‘ | Opposition | 1o05‘ |
| Leo 17o18‘ | Gem 22o35‘ | Sextile | 5o17‘ |
| Cap 04o19‘ | Lib 10o05‘ | Square | 5o48‘ |
In the first row, Planet 1 is at 12 degrees and 15 minutes of Cancer. Planet 2 is at 10 degrees and 03 minutes of Scorpio. When you glance at a pair of planetary positions to determine aspect, the first thing you want to see is the relationship between the signs. You can see that the positions are in Cancer and Scorpio, both of which are in the water element.
Different signs in the same element are trine to each other, or 120 degrees apart. So the planets in the signs are in trine to each other as well, in theory. In theory, because the actual degree separation could be less or more than 120. Consider two extremes. In the first extreme, the separation is exactly 120 degrees. If one planet is at 0 degrees of Cancer and the other is at 0 degrees of Scorpio, that would be an exact trine aspect, because the separation is exactly 120 degrees. Or, if one planet is at 12 degrees Cancer, and the other is at 12 degrees of Scorpio, that would again be an exact trine aspect.
The other extreme is when the planets are in different signs in the same element, but they are as far apart as they can possibly be. Consider a planet at 0 degrees of Aries, and another planet at 29 degrees, 59 minutes of Leo. Sure, the signs are in the same, fire element. But the first planet is at the very beginning of its sign of Aries, while the second planet is at the every end of its sign of Leo. The separation between them is 149 degrees and 59 minutes, or nearly 150 degrees! This is most decidedly stretching the definition of a trine, and for all practical purposes, not a trine.
So where should we draw a line? At what point does a separation stray so far off from the exact that it is no longer meaningful as an aspect? This is where the idea of the orb comes in. The orb is the offset from the actual separation. Consider again the planets in the first row of the table. The first is at 12 Can 15, and the second is at 10 Sco 03.
In order to ascertain an aspect, we always consider the shorter arc between the signs. In other words, Cancer-Leo-Virgo-Libra-Scorpio is the shorter arc as compared to Scorpio-Sagittarius-Capricorn-Aquarius-Pisces-Aries-Taurus-Gemini-Cancer.
One we have the identified the shorter arc, we figure what it would take for the planets to be in the exact same degree and minute position in their respective signs. In this case, we would get there if we were to advance the second planet from 10o Sco 03‘ to 12o Sco 15‘, to match the position of the first planet at 12o Can 15‘. The amount of advance–or the offset from the exact–is 2o 12‘, which is the orb. This is a very small orb, and is definitely acceptable. So these planets would be considered in trine to each other.
| Planet 1 | Planet 2 | Aspect | Orb |
|---|---|---|---|
| Can 12o15‘ | Sco 10o03‘ | Trine | 2o12‘ |
| Tau 03o23‘ | Tau 07o15‘ | Conjunction | 3o52‘ |
| Ari 23o15‘ | Lib 24o20‘ | Opposition | 1o05‘ |
| Leo 17o18‘ | Gem 22o35‘ | Sextile | 5o17‘ |
| Cap 04o19‘ | Lib 10o05‘ | Square | 5o48‘ |
In the second row, we have planets at 03 Tau 23 and 07 Tau 15, respectively. They are close to each other in the same sign. To make an exact conjunction, the first planet would have to advance a distance of 3 degrees and 52 minutes, so this is the orb. (This is the same as advancing a whole 4 degrees, to 07 Tau 23, and then deducting 8 minutes of arc to get back to 07 Tau 15, for an orb of 3o 52‘.)
In the third row, the planets are at 23 Ari 15 and 24 Lib 20, respectively. The signs of Aries and Libra are opposite each other.
In order to get an exact 180 degree separation, the first planet would need to advance a distance of 1 degree and 5 minutes, to get to 24 Ari 20 and line up exactly opposite the second planet. So the orb is 1o 15‘.
| Planet 1 | Planet 2 | Aspect | Orb |
|---|---|---|---|
| Can 12o15‘ | Sco 10o03‘ | Trine | 2o12‘ |
| Tau 03o23‘ | Tau 07o15‘ | Conjunction | 3o52‘ |
| Ari 23o15‘ | Lib 24o20‘ | Opposition | 1o05‘ |
| Leo 17o18‘ | Gem 22o35‘ | Sextile | 5o17‘ |
| Cap 04o19‘ | Lib 10o05‘ | Square | 5o48‘ |
In the fourth row, the aspect is a sextile. The shorter arc between Leo and Gemini is Gemini-to-Leo. The separation between the signs is 60 degrees. We need to determine the separation from Planet2 at 22 Gem 35 to Planet1 at 17 Leo 18.
If Planet1 (in Leo) were to advance by 5 degrees and 17 minutes, it would be at 22 Leo 35, an exact 60 degree separation from Planet2. So the orb is 5o 17‘.
In the last row the aspect is a square. Different signs in the same mode are either square or opposite to each other. Capricorn and Libra are both in the cardinal mode, and since they are not opposite, they are square, or at 90 degrees separation, to each other. (Capricorn is opposite Cancer.) Libra to Capricorn is the shorter arc. Planet 2 is at 10 Lib 05, and Planet 1 is at 04 Cap 19.
For an exact square, Planet 1 would have to advance to 10 Cap 05, for an orb of 5o 48‘. (This is equivalent to advancing a whole 6 degrees, to 10 Cap 19, and then deducting 12 minutes of arc to get back to 10 Cap 05, for an orb of 5o 48‘.)
Back to the question, what is an acceptable orb? 5 degrees, 10 degrees, 15 degrees…? Most astrologers use a maximum orb of 3-10 degrees. There are further nuances within this range, the acceptable orb then depending on the type of aspect, and the planets involved. I’ll address these separately in my posts detailing each of the aspects.
One last thing to know is that sometimes you will see what are called out-of-sign aspects. Here are a couple of examples.
For a conjunction, this means the aspect is between planets in adjacent signs. So, for example, you could have a planet at 28 Pis 01 and another at 02 Ari 05, which would be a conjunction with an orb of 4o5‘, but the planets are not in the same sign, i.e. out-of-sign.
For a trine, this would mean that the signs in which the planets make the aspect are not trine to each other, but the separation between the planets is still within orb of 120 degrees. Consider, for instance, a planet at 02 Sag 25, and another planet at 27 Can 12.
Sagittarius and Leo are trine each other, and so are Scorpio and Cancer. But Sagittarius and Cancer are not. However, because the first planet is in early Sagittarius, and the second planet is in late Cancer, they end up being nearly 120 degrees apart, with an orb of 5o13′. They are trine each other, but in an out-of-sign way.
You can imagine similar out-of-trine sextile, square, and opposition aspects. Astrologers are somewhat divided in how they interpret out of sign aspects. I’ll get to more of the differences between these and “regular” (in-sign) aspects in a later post.