I have been wanting to address this rather thorny issue for some time. There is a great deal of misunderstanding with regards to the tropical in relation to the sidereal, which requires a relatively simple approach. Strictly speaking, whatever that has been employed profitably for millennia requires no defence, but at this time. in the light of so much misinformation, an introductory case needs to be made. I shall begin with a brief explanation of the phenomenon responsible for the split between sidereal and tropical in the first place.

Figure 1 Earth Axis & Procession.

In understanding the nature of the sideral zodiac in relation to the tropical, we need to consider the Precession of the Equinoxes. The motion of the equinoxes along the ecliptic is caused by the cyclic precession of Earth’s axis of rotation.

Upon the compilation of the renowned star catalogue, which he completed in 129 BCE, Hipparchus observed that the positions of the stars had shifted from that recorded in earlier Babylonian (Chaldean) measures. He concluded that it was not the stars that were drifting. but instead the point of terrestrial observation. This apparent drifting backwards from the point of view on Earth is called precession and consists of a cyclic wobbling in the orientation of Earth’s axis of rotation with a period of 25,772 years

Hipparchus discovered another gem in his account of his discovery in On the Displacement of the Solsticial and Equinoctial Points, which Ptolemy subsequently described in his Almagest III.1 and VII.2).

Hipparchus measured the ecliptic longitude of the star Spica during lunar eclipses. He found that Spica was approximately  6° west of the autumnal equinox.  He then compared his own measurements with those of Timocharis of Alexandria, a contemporary of Euclid, who worked with a lesser-known Aristillus early in the 3rd century BC.  He realized that Spica’s longitude had lessened by approximately 2° Unfortunately. precise years are not offered in Almagest.

For many modern astrologers in the West, including contemporary traditionalists, the idea of using a sidereal zodiac is considered either irrelevant or anathema. The single most common reason for rejecting sidereal out of hand is in something that is neither technical or based on the perceived accuracy of outcome per se. It has to do with understandable protestations against changes in natal charts when tropical is converted to.sidereal.

There are other reasons, but this is by far the most common. That is to say, the detractors of sidereal do not act from a scientific or technical point of view. Of course, their position is understandable and not entirely without merit. One would require a very solid reason to switch from one zodiac to another. The better position from my point of view is to embrace both systems and apply either one of them wherever they are the better choice.  I will add here that reading both systems for a Nativity is not without reward.

The Precession of the Equinoxes produces an apparent drift of approximately one degree every 71.6 years. and it does so as if in reverse. A random tropical chart for 05 April 2019 – 3.50 PM GMT gives is the Sun at 16.32 Aries. If we calculate the same chart employing Fagal-Allen (sidereal) we have the Sun @ 21.32 Pisces..

Hipparchus of Nicaea (c.190 – c.120 BC), An image of Hipparchus from the title page of William Cunningham‘s Cosmographicall Glasse (1559)

Kenneth Bowser writes: “Late in the first millennium B.C., probably during the lifetime of Hipparchus of Rhodes (mid-second century B.C.), the Greeks introduced an innovation in zodiac reckoning that had heretofore been sidereal in the Near East and Eastern Mediterranean world for many centuries: they began to reckon the positions of planets and stars from the northern hemispheric vernal equinox. Until that time the equinox had been described in terms of the degree of the zodiac the Sun traversed when it reached the equinox, variously in the Greek world as 15°, 12°, 10°, 8°, 5° and 3° of Aries as precession slowly changed the Sun’s position in the zodiac at the time of the equinox.” The Tropical-Sidereal Debate, Part 2: The Sidereal Point of View

Sidereal comes from the same root as consider- From Latin sīdereus, from sīdus, sīder-, constellation, star. The Sidereal view is anchored in the stars and not based in reference to the Solstice and Equinoxes in the Northern Hemisphere – the latter is a Greek invention and certainly has its uses, by the word astrology itself refers to the study or wisdom of the stars. Western sidereal astrology is based on the Babylonian sidereal zodiac

A common criticism of sidereal is that the constellations are massively unequal in size, but of course the same is true for tropical observations. In fact, if anything, sidereal ought to be commended for the emphasis it places on the stars themselves. Indeed, the Indian use of nakshatras stresses the importance of individual or small clusters of stars, usually three.

Usually, when the subject of fixed stars comes up with modern astrologers. it soon becomes plain that the stars are of some interest but in the same way that asteroids, outer planets or even hypotheticals. They are seen as one more thing you can add if you so wish, whereas to a traditional astrologer, particularly a sidereal one. the stars are primary and the name of our art tells us this.

figure 1 Spherica Precession Diagram

One of the most vexing issues for Tropical practitioners interested in the stars is the issue of stars being ‘pushed’ out of their constellations, For example, one may have a Sagittarius Ascendant conjunct Antares, the Heart of the Scorpion. What can one do in such a situation? Most obviously, we can pretend it doesn’t matter. But when the Heart of the Scorpion is ripped out only to be artificially re-located to another sign, of a different element and in aversion., one either accepts the contradictions or looks more deeply into what we really mean by signs and constellations, as they

This second-century-BCE wooden plaque from Gansu, China, presents an outline of the Big Dipper, surrounded by constellations.

work in a tropical zodiac.

However, things are not quite so simple in practise. Western astrology has been heavily invested in the tropical view for at least two millennia. Our view of the zodiac has become a brittle one. Even though the Hellenistic methods came to us from astrologers who either used both sidereal and tropical or (less likely) they didn’t know which they were using because at that time the two systems were close to the same. From what I have gleaned, Hellenistic astrologers before Claudius Ptolemy used a sidereal zodiac for at least some purposes.

figure 2

They took this sideral zodiac from the Babylonians. The Indians almost certainly took their system at least in part from Babylon, although many Indian traditionalists claim that Vedic is of greater antiquity. However, the only genuine solution, if one’s aim is to is retain the original positions of stars in relation to sign. – in which case the stars are back where they are in their own signs. Few things illustrate this better than the 27 Indian Nakshatras with four Padas each, arriving at a total of 108 – a sacred number.

I mentioned that the Hellenistic astrologer used sidereal at least some of the time, but there is evidence that even in very early Indian astrology, the tropical zodiac was used. The reason for this seems rather obvious. The tropical zodiac is designed so that the first degree of Aries always falls on the Spring Equinox. In other words, this system measures and marks the seasons as we experience them in the Northern Hemisphere. There were no ancient forms of astrology known in the Southern Hemisphere, that resemble those of the Northern Hemisphere, but astrologers in the South either ignore the distinction or reverse the horoscope so that Spring in the North is Autumn in the South.

Here, we are back to the wold of Hesiod, where stars and asterism mark the times of the year for various agricultural activities, rainy and dry periods and so on.  It seems quite plain that tropical is by far the better Farmer’s Almanac and other forms of astrology such as Mundane would usually operate with the tropical zodiac. see figure 3.

So it is my contention that sidereal works best when used in Indian astrology because the whole system is essentially based on it. For those interested in the stars, as am I.

Fragments of a Babylonian Star Calendar

sidereal is the obvious choice. I would add that Indian astrology – by far the greatest group of siderealists, are also very interested in the

figure 3 – traditional astrological calendar showing the seasons

circumpolar stars. Ursa Major or the Big Dipper has seven stars known to Indian as Rishis or Sages. This constellation is almost certainly the origin of the ancient swastika symbol. See figure 2. The ladle-like arms mark the seasons.

It is my hope that this has served as a decent introduction to the two zodiacs. It’s intended as an introduction that is light on the technical side of the subject. In a forthcoming article, we will look more closely at how the sidereal works seamlessly with Indian astrology,

It is certainly the case that exploring sidereal astrology from an Indian point of view will by no means ultimately interest everyone. Nevertheless, I contend that study in this area will prove to be enriching and time well spent.