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The Great Tropical-Sidereal Debate

If we accept the sidereal zodiac, we would get to have Ophiuchus, the 13th constellation

Because we’re still in the Middle East, and are influenced by the East, where sidereal astrology got its start, I thought it would be as good a time as any to mention this rather irrational debate, which attempts to compare apples with… other apples.

There are many valid differences between the two zodiacal systems, but there is also such a thing as a turf war, and to hear a tropical astrologer defend his or her preference is very much like sitting through a two hour rant on whether or not one should use a period or semicolon between sentences. At some point, you want to leap up and scream, “Who cares?!?”


Perhaps you are befuddled.

Well, so am I.

Here is a strict-sounding person, explaining this:

The Tropical and Sidereal Zodiacs

Some Western astrologers use an alternative zodiac which is fixed relative to the stars rather than the seasons. This “sidereal” zodiac drifts further out of alignment with the tropical zodiac by about a degree every 72 years. Unlike in the tropical zodiac, in the sideral zodiac the vernal point moves from sign to sign as precession occurs; currently it is in the westernmost part of sidereal Pisces, and moving steadily further westward. In about three and a half centuries, it will cross into sidereal Aquarius; this is what is meant by the “Age of Aquarius”, and incidentally why we are said to be in “the dawning” of that age rather than the age itself.

About two millennia ago, these signs lined up neatly with the constellations of the same names. However, thanks to the precession of the equinoxes, the signs have moved about 25° west with respect to the fixed stars. For example, the Sun enters the sign of Aries (by definition) at the Vernal Equinox, on approximately March 20, but does not enter the constellation of Aries—the pattern of fixed stars with that name—until roughly April 14. Because it is tied to the seasons rather than the stars, the conventional Western zodiac is also called the “tropical” zodiac (the sun moves between the Tropics of Cancer and Capricorn at the equinoxes).

Precession of the equinoxes

The caveat to using the tropical zodiac is that it has become a shorthand version of reality used to explain “how astrology works”–it’s astrology lite. It’s the popular zodiac because it’s simple to use, but the real reason it’s relied on is because it’s traditional, and by now you should know how much I loathe accepting tradition for its own sake. It’s how Ptolemy defined the zodiac way back when, and apparently in the West, you’re not allowed to question Ptolemy, even though, let’s face it, he’s been dead a long time, and things have changed. Although the tropical zodiac bears little relationship to where the constellations are actually located, since everyone uses it, it’s the easiest one to reference when a question about the zodiac comes up during dinner conversation:

“Oh, by the way, did you realise that with the precession of the equinoxes, we won’t actually have the sun in Aries on March 20th anymore?” says Giles to Jill. Jill responds, with feeling “Oh, how devastating, darling. I had planned a trip to coincide with the sun entering Aries, and now you’re telling me, at the last minute, after all the plans have been made, the tickets bought, that the sun is where, precisely?” After this, an argument will erupt, in which the siderealist will be forced to defend reality, and the tropicalist will rely on information about the stars’ locations that hasn’t been true for A Very Long Time.

However, we cling to the tropical zodiac, in spite of its being dramatically wrong. Why?

Well, there is such a thing as blind foolishness in the field of astrological study. Astrologers are not known for embracing the harsh, cold, glaring light of reality; we are a group not known for logic and rationality. There’s nothing particularly rational about believing in astrology, after all—and it is a belief, not a science. It hasn’t been a science for approximately 550 years, but I don’t think that matters anywhere near as much as do those who would hold astrology to task for not being a verifiable, provable, scientific discipline. However, what acceptance of the sidereal zodiac asks of you is to listen to relatively complicated mathematical explanations about why the precession of the equinoxes affects where the sun is currently located, and my suspicion is that astrologers would really rather focus on psychology and myth than science.

Astrology is aligned with some of the oldest practices on earth; historically speaking, astrology is an attempt to correlate human behavior and occurrences with the rhythms and movement of the celestial sphere. There is a very human need to reach out beyond the limitations of the self, into the vast inky darkness, and make some sense out of it all, and contact the divine, while we’re at it. Astrology cannot be a science; it might be studied in an effort to appear scientific, but it will never live up to the rigors of experimentation, because that’s not what it’s for.

It is one of many ways we make some sense out of mystery. It is one of our ways of connecting with the divine; and finally, it is our attempt to experience the numinous, and explain it. Let’s not forget that no one can adequately explain what intuition is, yet it accounts for most of the “knowing” that goes on in your brain all day long, and intuition plays a large part in how astrology “works,” at least on the individual level of the astrologer interpreting a chart.

If you are not currently a siderealist, will you become one after reading this? No. Of course not. You and I are impervious to suggestion, and would rather use the tropical zodiac in spite of everything we know is true. I will address this perversity in our nature in another post, some day soon.

4 thoughts on “The Great Tropical-Sidereal Debate

  1. Pingback: Tweets that mention The Great Sidereal-Tropical Debate « Beyond the stars astrology -- Topsy.com

  2. I’m still very young, but very interested in astrology. I live in the east so of course I’ve really only been exposed to Tropical, I just now stumbled upon the fact that there has been a debate against it, and I love when one of my beliefs are challenged, so of course I read up on it. And I have to say, after reading this, I’m convinced. Sidereal is the way to go. By the STARS.

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