Synastry, or the comparison of birth charts, is a highly important astrological discipline when it comes to analyzing the “relational qualities” we do (or do not) share with another person…
This often manifests in the romantic domain, where one specifically seeks affective compatibility (Will they love me? And above all, how? See also my article Love, Psychology, and Astrology).
But it can also apply to other domains, since in reality, comparing charts enables a better understanding of the other person, whatever one does with that insight afterward !
Thus, it is found just as much in the parent-child relationship as in friendships, in employer-employee dynamics, even with one’s enemies, and so on…
This article does not aim to provide “the one exhaustive recipe” for making such comparisons, but it will offer you some important keys to understanding the overall mechanisms.
Performing Synastry: Methodology
1+Understanding synastry = understanding two charts
The first thing to grasp is that before comparing two birth charts, you must first succeed in achieving a solid understanding of each one taken in isolation !
This is truly the foundation, because if you do not understand the fundamental purpose of each birth chart, how can you possibly think to compare them ?
Is one person more social ? The other more introverted ? What are the planetary dominants (in sign, in house, etc) for each chart, considered separately ?
2+Elemental comparison
I cannot repeat this often enough: the Astrological Elements truly constitute the primary dominant that emerges. Through their simple analysis alone, one can already learn an enormous amount about a person !
The Elements represent the second division of energies, just after the Yin-Yang polarities (masculine/feminine, Animus/Anima), on a 3/4 basis: that is, 3 Zodiac Signs linked in Trine for each of the 4 fundamental elements (Fire, Earth, Air, Water).
Even through the elements alone, broad tendencies emerge regarding a person’s character and psychology…
For example, a Water-dominant individual and a Fire-dominant individual will likely need the mediation of various other factors to get along and understand one another well, which is not simple at the baseline !
3+Comparison based on chart shape
Birth charts form various basic patterns that integrate into personal House System…
Here too, simply through this integration, one can determine what is emphasized at the level of the fundamental quadrant divisions.
For example, does the chart emphasize the familial dimension, or conversely the transpersonal ? Is it more self-oriented or other-oriented ?
These are broad tendencies that are fairly simple to detect and allow one to outline general contours…
4+Comparison of Modes
Following the same principle, the Cardinal, Fixed, and Mutable modes constitute another fundamental division of our energies, and here too, they enable a different understanding of what is at play in a birth chart, and can reveal either antagonisms or complementarity.
5+Comparing the Suns
The Sun is the foundation of everything, the energetic source representing both the initial seed and the fundamental goal; thus, its comparison must be carried out attentively, including in the aspects it receives natally or forms to the other chart.
I already evoke these notions of solar compatibility in my articles on the compatibilities of each zodiac sign.
These archetypal energies are very important on a psychological level; they describe how we project ourselves into the world as men and as women (how we take action), and also what we attract, what we appreciate, what we need in terms of complementarity to evolve, so this is truly very important ! Especially on an affective level, of course, but not exclusively…
7+Mercury for the mind and socialization
Are you seeking to understand how a person thinks ? How they socialize ? What they like or dislike intellectually speaking ? Look to this planet and compare the two in each chart ! Obviously, this comparison will be all the more important if one of the two charts has Mercurian and Airy dominants…
8+Jupiter and Saturn: social radiance
With these planets, we already enter the generational dimension, thus less personal. It is frequent, for example, in couples to find few differences between these planets in sign… On the other hand, they obviously provide many indications regarding how we integrate into the world, so they are clearly not to be neglected !
9+Transpersonal planets: House placements
Due to their slowness, these planets are also generational; it is primarily at the level of House placements that comparisons should be made, both regarding the house in each chart and where the planet falls in the other person’s house.
10+Seek out prominent Aspects
It is often said that a picture is worth a thousand words, and this is often true.
Well, here it is somewhat the same: a Sun/Moon square or a Venus/Mars square, these are highly expressive energies… Provided the planets also carry various debilities, all these energies will inevitably mark the relationship !
Caution: this does not necessarily mean, however, that the relationship is doomed to fail ! It is not that simple… But it does mean above all that these energies will dominate the relationship in one way or another; they will lie at the heart of the exchanges and of its evolutionary principle…
Note that this point is obviously extremely important; one might say it runs parallel to all the other points !
Conclusion: Understanding the Nature of Our Relationships
This is the final point, very important, and the subject of a separate article.
It is essential to keep in mind that intrinsically, no relationship is “good” or “bad”; what matters above all is its evolutionary nature, what it has to offer us, and this is infinitely complex. There are structural and temporal notions that come into play; one cannot issue a definitive, dismissive judgment…
Here, then, is already enough to properly outline a chart comparison. Granted, you will need to delve more deeply into planetary comparisons, signs, houses, and interaspects, but if you simply apply the various foundational rules above, you will be in a position to understand the main guiding lines of your relationships !
Feel free to let me know in the comments or by email if you enjoy this kind of article; I may write more… 🙂