From 27 June 2020: Tropical vs Sidereal Astrology

A study group that I’m part of was looking recently at three possible zodiacs: the constellational zodiac, the sidereal zodiac, and tropical zodiac.

For those who are not quite sure what the differences are between these zodiacs, I’ll provide an explanation below, but I’d like to start off with the point I wanted to make first.

I’ve heard debates from time to time within the astrological community on the subject of which is better: the sidereal or the tropical zodiac. My viewpoint is that this is a dumb question, it’s asinine. As Robert Hand once famously said concerning the various house systems, asking if one is “better” than the other is like asking if German a better language than French.

It could be argued that both zodiacal systems couldn’t be “true”. It must be a zero-sum situation. One must be false and the other true, because in one system a person’s Sun can be in Libra, but in the other their Sun is in Scorpio. So how could they both be right?

The response to that question is: when looked at within the parameters of its own system of correspondences, each tradition (sidereal and tropical astrology) is “right” with respect to itself. It is like taking a photograph of someone from two different perspectives. We are looking at the same person, but from different points of view.

Indian astrology is based on the sidereal zodiac. It goes back 2000 years or so and it works just fine! So does Western sidereal astrology.

Tropical astrology has a history going back to early Hellenistic times, and it works just fine, too!

So which zodiac do I use? I use the tropical zodiac. Why?

Well, to be honest, I learned astrology at the feet of my uncle and aunt (Charles and Vivian Jayne), and they used the tropical zodiac, so that’s why I use it. And these days I have my hands full getting my head around medieval and renaissance astrology, so I don’t have time at present to add sidereal astrology to my toolkit. I’ll leave that to those who specialize in it. Just as there are many traditions within the community of magic, so there are within
astrology: we each choose the path that has heart for us.

Ok, that’s my viewpoint. In case you have no idea what I’m talking about, here is a quick explanation of the different zodiacs:

The constellations in the sky are not of equal sizes. For example, the constellation Virgo is much larger in terms of zodiacal longitude than Cancer. They are of unequal size. This is the way the stars look in the heavens when we view them. This is the zodiac that the ancient astrologers used.

Eventually, by the 5th century BCE, the astrologer-astronomers of Mesopotamia standardized the zodiac so that it contained twelve signs of exactly 30° each. This is referred to as the sidereal zodiac and is an idealized division of the zodiac – the ecliptic of the Sun – into 12 equal parts: 12 signs of 30° each. The sidereal zodiac roughly corresponds visually to the actual constellations that we see in the sky.

When Hellenistic astrology was developed a few centuries later, the seasons were roughly aligned with the sidereal zodiac. The beginning of the seasons aligned with the cardinal signs: Aries, Cancer, Libra, and Capricorn.

The tropical zodiac is measured relative to the seasons; its starting point is the vernal equinox at 0° Aries. After that, the other signs are measured out in 30° increments starting from there.

That the qualities of the 12 signs were drawn from both the sidereal and tropical zodiacs became problematic later on when the two zodiacs started drifting apart due to an astronomical phenomenon called precession. this phenomenon is known as the precession of the equinoxes.

Precession is due to the Earth wobbling on its axis very slowly over the course of 26,000 years. The result is a drift between the two zodiacs of about 1° every 72 years, with the two zodiacs differing presently at about 24°. This ends my brief technical explanation.