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Reconciliation of the Tropical and Sidereal Zodiac
Part I of IV
by Vic Di Cara
Editor's Note from Pat Lantz: This is part one of a wonderful four part series in which Astrologer Vic Di Cara reconciles the two zodiacs, sharing with his readers some forgotten knowledge that will give all astrologers, both Eastern and Western much to ponder about both the "sidereal zodiac" and the "tropical zodiac".
The universe is, in an obvious and literal sense, our mother. We exist in her womb and are made from her substances. The stars and planets of the heavens are part of our mother’s visible body. The way the planets and stars move is her "body language" revealing what how the universe will move to care for the upbringing of us, her children. She communicates to us in this way to help us navigate and understand the destinies we have created for ourselves over countless lifetimes on a great journey towards self‐realization.
In any language it is important to grasp the fundamental grammar. Astrological grammar has three primary parts:
1) The planets
2) The space through which they roam ‐ the “zodiac”
3) The way this space relates to a given time and place on earth ‐ the “houses”
In this paper I will address our understanding of the second part of basic astrological grammar: the zodiac. Being a basic topic does not make it less important. On the contrary that which is fundamental is essential. This fundamental topic is in dire need of address because the international community of serious astrologers has not yet agreed upon how to even define it!
What’s the Problem?
Stated basically, there are two opposing ways to define the zodiac:
1. In reference to the stars
2. In reference to the Sun's relationship to the earth.
The first is what we call a "sidereal zodiac" and the later a "tropical zodiac". Most astrologers pick one side of the debate and denounce the other. In this paper, however, I will explore reconciliation between the two.
Sidereal Twelvefold Zodiac – A Zodiac of Stars?
My background and roots are in Indian astrology (“Vedic astrology”). Naturally, I will explore this topic from that vantage point, but I am confident that what I discover will be of significant value to the entire international astrological community regardless of school or denomination.
If you know anything about Indian astrology, the first thing you probably know is that we use a sidereal twelvefold zodiac. That’s my starting point. At first, I figured the tropical zodiac was some kind of mistake; or perhaps at best a theoretical system. After all, I could look down at my sidereal calculations telling me the Moon was in Taurus tonight, and then look up in the sky and see with my own eyes that the Moon really was in Taurus. So, the sidereal zodiac initially struck me as the obvious, real and accurate one.
But sometimes I would look down at my sidereal calculation telling me Jupiter was in Aries, for example, and then look up to see it playing with one of the fish of Pisces. The real constellations themselves, I figured out, are all sorts of different sizes. Some take up a lot more space in the zodiac than others. But the sidereal zodiac in my astrological calculations has all the twelve signs fixed at perfectly equal size: 30° each.
So, the twelve sidereal signs are really not identical to the twelve constellations.
Now that we are asking questions, if it really is a zodiac of stars, why are there twelve? According to traditional definitions of the night sky, there are thirteen constellations in the zodiac belt. You see twelve, someone else sees thirteen, I might see five symbols up there. Who defines which is correct, and based on what logic?
These are rhetorical questions, mind you, which I will soon answer. But for now what I want to know is, if the sidereal signs are not literally a zodiac of the stars, what are they?
What is the Twelvefold Sidereal Zodiac?
The question was: Why does the twelvefold sidereal zodiac have twelve equal divisions in spite of there being thirteen unequally sized zodiac constellations? The answer is: Because each division does not represent a constellation! Each division represents the amount of space traversed by the Sun in the amount of time it takes the Moon to make a complete revolution through the zodiac.
The Sun and the rest of the planets roam through a relatively narrow band of space. One complete lap of the Sun through the whole thing is the essential definition of a “year.” During each year, the Moon makes twelve complete laps through the zodiac, each the same length. Each lap is the fundamental idea of a “month” and a “sign.” This 12:1 relationship between the motions of the Moon and Sun is precisely why we have twelve signs in the zodiac, and is why each sign is the same length.
We designed our clocks to reflect this. Each of the twelve numbers on a clock face marks the distance traveled by the hour hand during a complete revolution of the minute hand. Similarly, each border of the twelve zodiac divisions marks the distance traveled by the Sun during a complete revolution of the Moon. The beautiful clockwork of Mother Nature creates the twelve signs of the zodiac, not some fanciful connect‐the‐dots game played in the sky.
Both systems, tropical and sidereal, use these mathematical ratios representing the Sun and Moon to define their twelve divisions. Neither uses the stars themselves. Our language reflects this. We call the divisions “signs,” not “constellations.” OK, sure, English is a sloppy language, but even in Sanskrit – which is anything but a sloppy language – we call them rāśi, not nakṣatra. The word nakṣatra directly refers to heavenly bodies: stars and planets. The word rāśi on the other hand is an abstract word that has nothing specifically to do with stars, and instead is a mathematical term referring to degrees collected in an angle of arc.
Despite advertising to the contrary, the sidereal twelvefold zodiac is not the stars themselves. What then is the difference between tropical and sidereal signs?
The Real Difference between the Sidereal and Tropical Conceptions
The only real difference between the sidereal and tropical conceptions of the twelve signs is where they choose to start from. Both of them are equal divisions of space based on the twelve months of the year (a.k.a. the twelve lunar cycles in a solar cycle). The only difference is what point in space they pick to start marking the division from.
The tropical zodiac starts relative to the Sun crossing the equator heading northward (the “vernal equinox”). The sidereal zodiac is supposed to start at the beginning of the constellation we call Aries. But, where is that? Remember, the sidereal zodiac is not exactly the stars themselves, so it’s not that the first star in Aries is the beginning of its sidereal sign, and the last star is its end. There are many opinions about where sidereal Aries begins, and thus many different versions of the sidereal signs. They all are in the same ballpark, setting the start of Aries somewhere about 40° west of the star named Aldebaran.
Which One is Better?
To my sensibilities, the “better” zodiac would be the one that makes more sense and is somehow more “original” and “authentic.” Trying to figure out which one is more original leads us to discuss the “precession of the equinoxes.” It takes a certain amount of time to get from one vernal equinox to the next: A year. And it also takes a certain amount of time for the Sun to move from one star, around the whole plethora, and back to the same star. How much time? Also a year. They both take “a year” but they are not the same amount of time. They are slightly different. Twenty minutes different. So they phase slightly out of sync as centuries pass.
The point of the vernal equinox therefore very slowly drifts (“precesses”) in relation to the stars. About 2,000 years ago it was aligned with what we now consider the beginning of the constellation we call Aries. So it appears that this was the time in history where the two ways of calculating the twelve signs overlapped and blurred.
Siderealists examine this clue one way, tropicalists another. Siderealists say that we wrongly took the names and qualities of the twelve constellations and ascribed them to the twelve mathematical divisions of the year. Tropicalists, on the other hand, say that we wrongly took the names an characteristics of the twelve mathematical divisions of the zodiac and ascribed them to stellar constellations.
Who is right?
Continued in Part II
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About the Author
Victor Damien DiCara practices astrology based on very ancient principles ("Vedic") but does it with a very modern frame of mind.
Initiated into Vedic spiritual culture in 1992 (in India), Vic was awarded the symbolic thread of the brahmin in 1994. This award signified aptitude in the role of a councilor, philosopher and guide. While living as a celibate yogi in an ashram for 8 years, he studied Vedic philosophy and the culture of Vedic astrology and began offering astrological consultation to the public in 2007. (Vic's astrological autobiography)
Vic has written and published in over a dozen magazines, has published textbooks for his courses on astrology and is currently putting the finishing touches on a full length book.
To find out more about Victor DiCara, visit his Website, Authentic Astrology, Blog or join him on
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