How to Interpret Aspects in Astrology

One of the places I got completely stuck when I was first learning astrology was the issue of aspects. Probably because when I first drew my chart it looked something like this:

Screenshot 2019-02-25 12.23

To which I said,


That’s quite the knot to untangle, even for a visual-spatial learner like yours truly. I had an inkling of what to do with a planet in a given sign and was even starting to get into issues related to houses—but when it came to getting my head around the aspects in my birth chart, I was up the creek. I wasn’t going to give up that easily though.

The astrology bug bites hard.

In this post, I’m not only going to explain how to interpret aspects, but I’m also going to give you a starting place into understanding the “why” of astrological aspects so you can begin to get your head around the “how!”

What is an Aspect in astrology, anyway

To put it as simply as possible, aspects are how we describe the relationship between planets. Understanding aspects in your chart gives you a window into the dynamic stories that are playing out in your life.

An aspect in astrology occurs when a planet is at a certain number of degrees away from another planet or point in the chart. For example, when two planets are around 90° from one another, we say that they’re in a “square” aspect (a square has four 90° angles).

What that means is this: those two planets are in a relationship with the character of a “square.” Think of the language we use in English that describes squares: “squaring up” before a fight. “Squaring off.” “Square peg in a round hole.” That should tell us that there’s something adversarial about a square: something tense, a real “can I speak to the manager” situation.

If you’re like me, you want to know where this concept comes from; keep reading. If you’re not like me and you just want to know what aspects signify what kinds of relationships… well, scroll on down 😉

To give aspects in astrology their due, we must take a detour into classical optical theory, because the word “aspect” literally means “look at” (Latin ad, “at, to” + spectō, “I look”). I just heard half of you slam your head on the desk. “I just wanna know when I’ll meet my soulmate!” I see you, I hear you, but stay with me!

It’s important to remember that the ancients conceived of the planets as active agents, not as passive on a cosmic timepiece. We start off with the idea that, in the astrological ball of wax, planets interact with each other by casting glances at one another. Kind of like this:


If we’re looking at something, what we are doing is bearing “witness” to that which we are observing, and many of the ways traditional texts talk about aspects include descriptions of planets “witnessing” each other. The astrologer Chris Brennan discusses this at length in his game-changing book, Hellenistic Astrology: The Study of Fate and Fortune, beginning on page 292 (that’s an affiliate link; I get a kickback if you purchase a copy). If you’re serious about astrology at all, that’s a book to have on your shelf.

These glances in the ancient world were conceived of as an exchange of energy. The short version is that people imagined that the human eye was emitting ethereal light called “lumen,” which was invisible but illuminated anything it fell on. Anything that this lumen hit was “illuminated,” and returned visible light, called “lux,” to the beholder.

We see this reflected in literature of the day, including the New Testament (Matthew 6.22-23, NRSV):

“The eye is the lamp of the body. So, if your eye is healthy, your whole body will be full of light; but if your eye is unhealthy, your whole body will be full of darkness. If then the light in you is darkness, how great is the darkness!”

Lux. Lumen. Lewks. They make aspects work. Got it?

In modern astrology, we’ve lost the connection to optical theory and now it’s more to do with vibrations, from the ways I’ve heard it explained. It’s as though the planets “resonate” with each other at certain angles, creating consonant or dissonant harmonies. This vibes well with the way many new age folks talk about vibrational frequencies. But even that has some ancient roots!

Aspects and Musical Harmony

There are five main aspects described by Ptolemy and agreed upon in general by the astrologers of the ancient world up through the renaissance and early modern era.

These five aspects are as follows: the conjunction (0º), the opposition (180º), the trine (120º), the square (90º), and the sextile (60º).

Ptolemy explains that these divisions of a circle are important precisely because they represent the primary divisions of the octave in music (cf. Tetrabiblos I.13). Each division correlates to a harmonic interval: correlate to the unison (conjunction), the octave (opposition), the fifth (trine), and the major third (sextile).

You’ll notice that I skipped over the square.

If you play the note exactly halfway between the top and bottom notes of an octave, the interval that results is actually the most dissonant interval in music, the tritone (also known as a diminished fifth or augmented fourth). This musical interval corresponds to the astrological square: halfway between the conjunction and the opposition.

This is whence the language of “harmonious trine” and “tense square” emerges historically, but I don’t think this is commonly known (although I can’t imagine astrologer-musicians throughout history Rudhyar or Ficino would have overlooked this, but I haven’t read enough of them to have the sources on hand).

For those keeping score at home, the modern equally tempered octave has twelve notes in it—but, the zodiac preceded the chromatic scale. Greek music used tetrachords: 4-note scales!

Okay, so what? How do I actually interpret aspects in my chart?

To interpret an aspect in your birth chart, you’ve got to take the aspect apart first by asking yourself several questions:

  • Which planets are involved?
  • What aspect is involved
  • Which planet is faster?
  • What houses do the planets rule?
  • What houses are the planets in?

It gets complicated quickly, but if you get used to doing this over and over, it becomes second-nature! It’s like learning your scales and arpeggios, to continue the musical metaphor. Let’s break this down!

Suppose you’ve got Mars sextile Jupiter in your birth chart, and say that you’ve got Aries rising, and that you were born at night. If you were to look at the sky at the moment of your birth (and it was nighttime) you’d see Mars rising bright over the eastern horizon. Drawn on a chart, it looks like this:

aspects mars in chart 1

As a rule, planets in astrology can see things in the sign where they’re at. Planets also emit seven “rays” of lumen to the degrees that they can see by the aspects we talked about above. So, Mars is hitting a certain collection of signs with his lewks, and so we say he can behold those signs. From Aquarius, Mars can behold Aries, Taurus, Gemini, Leo, Libra, Scorpio, and Sagittarius. Really, anything in Aquarius can see anything in those other seven signs—there can be an aspect there.

aspects mars with lines

Now, Mars cannot behold anything in Pisces, Cancer, Virgo, or Capricorn from where he sits in Aquarius. So, we say that anything in those signs is “averse” or “in aversion” to Mars, and likewise we can say that Aquarius is “averse” or “in aversion” to those signs. We can spend a lot of time on that, but here’s a visual reminder:

aspects mars aversions

Say that a planet is in any of the signs that Mars can behold from where he sits in Aquarius, so, let’s say it’s Jupiter in Sagittarius. That means Mars and Jupiter are in aspect by sign. So, right now, Mars and Jupiter can see each other because they are in signs that can behold one another. We call this a “sign-based aspect.”

aspects mars jupiter sextile

If two planets are in sign-based aspects, they can interact with one another. The nature of their interaction, whether friendly or hostile, is determined by the nature of aspect. Here’s the juice:

  • Conjunction: two planets are working together according to their natures (e.g., Venus helps, Mars hurts, etc.)
  • Sextile: gently supportive and easy, but not very dynamic
  • Square: tense and combative, but sometimes passive aggressive
  • Trine: flowing, makes things happen, but not necessarily always “good” in a strict sense
  • Opposition: well, it’s in the name. Overt fighting, explosive, a blow-out!

Sign-based aspects describe the overall tenor of planets’ relationships with each other. But planets don’t interact directly with one another until they come to a degree-based aspect within a sign. That would mean that when Mars advances to a later degree of Aquarius, to meet the square that Jupiter is casting there, which activates whatever this relationship signifies.

Let’s put the story together!

Mars moves faster than Jupiter (usually, unless Mars is retrograde), so Mars will be the one who is approaching Jupiter here. Because it’s a sextile aspect, Mars and Jupiter are in a supportive relationship with one another. Think of it like this: Mars is approaching Jupiter as a friendly acquaintance and asking him for help with something. Since Jupiter is, by nature, a friendly guy, and since he’s in his own sign of Sagittarius and has access to his own resources, Jupiter’s happy to share out of his abundance with Mars.

Good so far?

The last step is to figure out what parts of life the aspect is describing, and you figure this out by looking at which houses the planets involved rule. So in this example, with Aries rising, Mars rules the first house of your basic personality, body, health, vitality, appearance, and overall circumstances, as well as the eighth house of the unavoidables: fear, death, and taxes. Jupiter, meanwhile, rules the ninth house of education, spirituality, and travel, as well as the twelfth house of limitations, sorrow, and the unconscious. Mars is placed in the eleventh house of friends and groups, and Jupiter is placed in the ninth house, which I already described.

Let’s plug everything into this formula:

[Faster planet] representing [material of houses ruled by faster planet] approaches [slower planet] who rules [material of houses ruled by slower planet] in a [character of aspect] way and this creates [positive/negative based on the nature of the aspects and the planets involved] impacts in the area of [house where the faster planet is].

That gives us:

Mars, representing the native’s body, health, appearance, basic personality, approaches Jupiter, who rules philosophy, religion, travel, and education, in a gently supportive way and this creates positive impacts involving the native’s friends and associations.

Then you see where that takes you. In this example, we can see how the native’s personal circumstances can be improved by making efforts to connect with people who share their beliefs, philosophies, and values. Doing so serves them quite well and has the ability to improve their social standing. That’s just a very basic interpretation, but we can dive deeper into how this aspect plays out within the life of the native by looking at their unique context. That’s what we’d do within an astrological consultation.

I’m still lost!

It takes quite a bit of time to learn how to interpret aspects in this way, and I didn’t even get into the difference between applying and separating aspects! But if you take the time to get this rhythm into your bones, you’ll be able to interpret aspects in your birth chart with more ease.

Remember that astrology is a long apprenticeship, too! It’s always helpful to get another set of eyes on your chart, and I’d love to be able to help you out with that.

Get your aspects untangled—book now!

If you want to practice interpreting aspects on your own, great! I’ve made an aspects worksheet PDF for you that has all the information on aspects and houses you need to get used to the rhythm of interpreting aspects (plus some extra stuff on applying and separating aspects). To get your copy, all I need you to do is to sign up for my email list here.

Was this helpful to you? What questions do you still have? Let me know in the comments!

3 thoughts on “How to Interpret Aspects in Astrology

  1. Laurel Humphreys says:

    I had begun self study of astrology a decade or so ago. Had begun learning aspects and houses and that is where i found it difficult to keep everything accessible in my brain! I also had huge changes and little time to spend on esoteric learning so i shelved it. Til Feb of this year I joined Twitter and decided to follow astrologers to see if I could absorb ideas. Hence found your article, and found it extremely helpful in the sense of helping forge categories and connections in my brain. Thank you!

    Was there a reason you chose the aspect that you did in your example? Your piece also piqued many curiosities. Thank you for the synapse salad.


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