true sidereal

Building on the oldest traditions of sky-watching that we know of, True Sidereal Astrology is a branch of western astrology which uses the bounds of the ecliptic constellations instead of an approximate zodiac. ‘Sidereal’ means “oriented to the stars”, and ‘true’ means “exact” or “precise”. In true sidereal astrology, the sizes of the signs vary in accord with the sizes of the constellations after which they are named. This stands in contrast to most other modern forms of astrology, which use a zodiac of 12 uniformly sized signs (of 30° each). Mainstream western astrology (AKA tropical astrology) uses a zodiac which isn’t oriented to the stars, even though the literal meaning of the word ‘astrology’ is “language or logic of the stars”. It can be a confusing scenario to take in, but it’s worth understanding! Let’s look a little closer…

The signs of the true sidereal zodiac are variable in size, relative to the living sky

The best place to start is at the beginning… Did you know that modern astrology emerged  from our ancestral star-watching roots? …that the classic zodiac signs (Aries, Taurus, Gemini, etc) are named after the constellations that the moving bodies in our Solar System pass through?  Ok… but did you know that in ancient times and through its early evolution, astrology was aligned precisely with astronomy, but was de-coupled from that science almost 2000 years ago? That was a time when the most popular teachers taught that the Earth was the absolute center of a universe which rotated around it. Astrology in the west hasn’t lined up with the living sky since then, even though all (yes categorically all) of the classic western (Ptolemaic) ideas that we inherit about the planets and signs actually arose from watching the living sky itself! The story gets worse, unfortunately…

Astrology emerged as a celestial science, and was known in ancient Greece by a name that translates as “divination by means of astronomy”. Today however, mainstream western ‘astrology’ drifts ever-and-ever-further out of alignment with the actual stars. This drifting is due to the almost imperceptible movement of the stars (relative to our seasons and solsticial sunrises), a phenomenon known as ‘precession’ (or ‘precession of the equinox’); the stars seem to drift at a rate of ~1° per ~72 years. Over the centuries since the height of ancient Greek culture (and the shift towards use of the tropical zodiac), mainstream astrology has shifted ~25° out of alignment with the constellations of the living sky. Since a standard zodiac sign is only 30°, tropical astrology today is out of tune by almost a whole sign! How did that actually happen?! well, there are answers…

The Ptolemaic heavens; Earth supposedly orbited by Moon, Mercury, Venus, Sun, Mars, etc

Unique unto itself, tropical astrology orients its zodiac to the seasons of the northern hemisphere instead of orienting it to the stars. This logic is not only Geo-centric (Earth-centered), but also Euro-centric (the seasons are totally opposite in the southern hemisphere!)… while today we know that our solar system is Helio-centric (Sun-centered). We also know that the fixed stars drift (~1°/72yrs) relative to the Earth’s seasons… but our mainstream (tropical) western zodiac remains oriented to an idea which reflects the ignorance of a bygone era. In ancient Greece, Aristotle and other popular teachers promoted the superstitious idea that the entire cosmos (including the Sun and all our planets) revolved around the Earth at its center. The tropical zodiac and what would become modern mainstream astrology arose in the shadow of that error.  

Although the 2nd century astronomer & astrologer Claudius Ptolemy did note that the star positions had changed slightly over time, he did not have the foundation of knowledge needed to understand why this was so. He seems to have deduced that the fixed stars were moving, and therefore they were untrustworthy… hence, he adopted the idea that the zodiac should be organized around a terrestrial event; the spring equinox sunrise. This seemed much more trustworthy to him, because according to the prevailing thought of the day, the Earth was fixed, but the stars obviously movedPtolemy’s works on astronomy and astrology are some of the only surviving works on those subjects from his time period (due largely to the loss of the Library of Alexandria), and he is generally credited with being the main reason that Greek astrology shifted to the tropical zodiac, paving the way for our modern situation. Each year, the tropical zodiac is adjusted so that 0° Aries aligns with the sunrise of the spring equinox (regardless of what constellation the Sun is actually rising in). 

The Spring Equinox Sun hasn’t actually risen at 0° of constellation Aries since Claudius Ptolemy was alive, (it’s currently well into Pisces and around 2770 will enter constellation Aquarius). However, its important to understand that in the 2nd century, when Ptolemy’s arguments for tropical divorced astrology from the skies, there was no meaningful difference between tropical and sidereal. Today there is, though! Over time, sidereal zodiac will always be aligned to the stars and constellations as they are in the sky. However, a tropical zodiac over time will slowly fall out of alignment with the heavens, like a broken clock that’s only right once every ~22,000 years! So what do we do until then?

tropical zodiac and constellations
Tropical zodiac overlayed onto the living sky (note the ~25° difference)

Precession is real, even if we don’t really notice much difference in the stars over the course of a lifetime. Over the course of centuries and millennia, however, major differences inevitably develop (see image above of the tropical zodiac compared to the living stars: Note that sign Libra is populated by constellation Virgo, sign Virgo by constellation Leo, and so on around the entire zodiac). The practice of True Sidereal Astrology always uses a zodiac with high fidelity to the actual skies. If the Moon is in the stars of constellation Virgo, True Sidereal Astrology addresses it as a Virgo Moon. We don’t say that it’s ‘in Libra’. This is aligned with the way astrology was developed and practiced by our ancient ancestors worldwide. Sky-watchers such as the ancient Greeks, Egyptians, Mayans, Sumerians, Babylonians, Tibetans, Chinese, and Indian cultures all charted the motions of the planets and luminaries through the living stars, and compared them with patterns of activity on earth within society and within individuals… this is where the logic of astrology, the language of the stars, arises from. 

As a branch of western astrology, True Sidereal Astrology, through the Greek tradition, evolved from roots in Babylonian celestial science. In ancient Sumer and Babylon they used 18 unevenly sized constellations, before these were later simplified to the 12 zodiacal signs we know today. This simplification did allow astrology to survive the European dark ages, during which people were not widely numerate. Today we have the computing technology to return to the ancient roots of astrology – and calculations which would have taken months, reserved strictly for royalty, now take just a click and are available to everyone!