Let’s imagine several race cars running around a circular track. Those are planets moving along the ecliptic. Astrology studies this movement of planets, and the patterns they form at specific moments in time. An important part of those patterns are aspects, i.e. interactions between planets.

How can race cars interact? Well, they can overtake each other when they pass the same point along the track. Planets have this kind of interaction too, it is called a conjunction. But planets have more options than cars do. For example, they form an interaction, or aspect, when they are exactly opposite each other along the ecliptic, i.e. the angular distance between them is 180º. This is called an opposition. Or when the angular distance between them is 120º, this is a trine. There are several other aspects as well, square (90º) and sextile (60º) being the most notable.

Aspects like these are widely known and used by students of astrology. When an astrological software outputs a natal chart (a snapshot of the sky at the moment of birth), these aspects are usually depicted in bright colours and are visible. Have you noticed that I never mentioned the parallel so far? Even though it’s an aspect too.

The popular astrological software Solar Fire could display parallels in the chart in its earlier versions, but not anymore. There are other, not widely known astrological software packages, even free ones, that can still do that. Quite commonly though, parallels are forgotten nowadays. I think the main reason for this forgetfulness is the fact that they aren’t visible in the chart. Earlier sources of astrological knowledge (before astrology in the West was reduced to ashes by the fans of materialism), like reasonably well known William Lilly and many of much less known but very bright minds before him, do state that parallel is at least as potent as the strongest of common aspects, the conjunction. It isn’t easily distinguishable visually, that’s the problem. And the contemporary students of astrology do not bother to dig just a little bit deeper. So what are exactly those mysterious parallels?

Let’s return to our racing cars. Let’s say the race track is 40 meters wide, and it has a centerline marked on it. Let’s say one of the cars, car A is currently exactly 20.0 meters to the left of the centerline, and another car, car B, is also exactly 20.0 meters to the left of the centerline. No matter where they are located along the track. If they were not cars but planets then according to the rules of the traditional astrology they would be in the aspect of parallel. Can you see what’s the essence? They are moving at the same distance from the centerline, and so it doesn’t matter where they are along the track — they are connected!

So the main reason why parallels are forgotten in contemporary astrology is that they are measured in the direction perpendicular to the printed natal chart. That chart is 2D whereas parallels are measured in the 3rd dimension.

Are you still with me? If yes then I guess you are waiting for a technical definition of astrological parallels, without flimsy allegories. Well, I am more than happy to help you out. However, I will use this opportunity to promote my other pieces of writing, partially because, according to my observations, many of even otherwise competent students of astrology neglect the basics of astronomy. Despite what current astronomers say, astronomy was traditionally the servant of astrology, and its only raison d’être was to serve precise enough data to astrologers.

First of all, do you know what the ecliptic is? If you don’t, or if you are unsure, please read the "About the Ecliptic" note below.

Next, do you know what’s the relationship between the ecliptic and the celestial equator? If you don’t, or if you are unsure, please read "The Ecliptic and the Celestial Equator" note below.

I would also advise you to read the "The Travels of the Sun" note, as it brings both important concepts together.

Are you still with me? Fantastic! Now that you understand that the Sun is sometimes further from the celestial equator (like at the times of summer and winter solstices) and at times its spot on the equator (like at the times of spring and autumn equinoxes), you can understand the idea of the Sun’s distance from the equator. It’s at its maximum (about 23.5º) at the solstices, and it is zero at equinoxes. This distance is called declination. And why is it important for us? Because the aspect of parallel is formed by two planets having an equal declination.

Declination is measured in the direction more or less perpendicular to the direction of the ecliptic, this is why you can’t see it on the common astrological charts, which are 2D. Magi Society has devised a chart showing the third dimension, but that’s a topic for a different discussion.

Declination is measured in two directions, it can be towards the North Pole (in which case it is considered to be positive, or simply North), or towards the South Pole (when it’s negative, or South). So parallel occurs when both planets are equidistant from the equator in the same direction (both are North, or both are South). And what if they are equidistant from the equator in the opposite directions (one is North, the other is South)? Then that’s the aspect of contra-parallel! Which in tradition was considered to be similar to the opposition, but Magi Society believes it’s pretty much the same as the parallel.

Now that I told you all that, and you are still with me (the probability of which is very close to zero), I can tell you that the parallel I told you about is the most popular kind of parallel but not the only one. That is the parallel in declination. There is also a parallel in latitude. I mean the ecliptic latitude.

See, the planets’ positions we are used to in astrology are measured in ecliptic longitude (their distance from the zero point, the point of the vernal equinox, in degrees and minutes) but usually expressed in the signs of the zodiac. Still, bearing in mind that each of the signs of the zodiac occupies 30º of the ecliptic, a planet’s position in the zodiacal notation can be easily converted to its ecliptic longitude. For example, if the Sun is located at 11º 30’ of Leo since Leo is the fifth sign of the zodiac, its ecliptic longitude is 131º 30’. Easy enough.

Now, there is also such a thing as the ecliptic latitude — it’s the distance of a planet from the ecliptic. The ecliptic latitude of the Sun is always zero by definition (since the ecliptic, as you remember, is the path of the Sun among the stars). However, other planets do have some ecliptic latitude, and some of them, like Pluto, can wander quite far from the ecliptic. So if two planets have an equal ecliptic latitude, they are considered to be in the parallel in ecliptic latitude. They can also be in a contra-parallel if they are equidistant from the ecliptic in different directions. But a parallel in ecliptic latitude is seldom if ever, used in astrology. Whenever you hear of a parallel, that’s a parallel in declination, for sure.