Tell me if this sounds familiar…
“The Zodiac is wrong!”
“There are really 13 signs!”
“You thought you were a Scorpio, but you’re really Ophiuchus… or worse… You’re really a Libra!”
“Noooooo!!! AAAAAAHHH!!! My identity is shaken!!! Who am I???”

So, this is my explanation as to how the ‘big shift’ happened and why if you aren’t using the system that follows the actual constellations, and includes this 13th sign of Ophiuchus, you’re still the sign you always thought you were.
I swear, the way this pops up every few years like someone thinks it’s some new information that’s gonna BLOW YOUR MIND! is like… some weird, cosmic, timing, thing…
Anyway, the recent trend seems to have metastasized and infected social media this time around. People have been telling me about a TikTok or Insta reel that spreads this.
I myself watched a short video of Dr. Neil deGrasse Tyson on “The Late Show with Stephen Colbert” explaining how the zodiac signs are off from the constellations, so you’re probably not the sign you think you are, and there’s this new guy hanging around named Ophiuchus… and so on.
As previously stated, in my blog article here, about this topic in 2011: If you want to know about what’s going on with astrology, ask an astrologer.
Dr. Tyson is amazing. I enjoy his work so much. I’m a science nerd and the work he does for education is outstanding. But, he’s not an astrologer. He doesn’t practice astrology. He doesn’t believe in astrology. He hasn’t studied astrology.
He’s not expected to have in-depth knowledge or awareness of how astrology works, its history, its mythology, or its use.
Hell, most people who do believe in or enjoy astrology don’t even know all this stuff!
Dr. Tyson is too busy being an astrophysicist and we love that for him!
But to explain in more detail as to how this whole “12 signs is wrong, there are 13” or “The zodiac is off by a whole constellation, so you’re really ____, when you thought you were ____,” is really going down:
No. You are still whatever sign your zodiac book/magazine article/phone app says you are, because the astrological system those are based on is different than what Dr. Tyson is talking about.
Please keep this small detail in mind as you read — an astrological or zodiacal sign is not necessarily the same thing as an astrological or zodiacal constellation.
A constellation is a group or pattern of stars.
An astrological sign is a specific meaning or reference of purpose given to a point in space, which might be lined up to a constellation, but doesn’t have to be.
The Ecliptic is the imaginary line the sun (and in astrology, the moon and planets) take as it arcs through the sky. The Zodiac Constellations are the ones that are in this pathway, and so the sun seems to go through them throughout the year.

It’s also important to know about something called The Precession of the Equinoxes to understand this idea of the zodiac “being off by one sign.”
When we observe what is going on in the heavens, we learn when to expect significant, repeated points on the calendar. Days grow shorter and longer, looping around with two days in the middle of this cycle where everything evens out. Day and night are equal. Thus, equi- equal and -nox night.
Because the orbit Earth takes around the sun isn’t an exact circle, but is elliptical, and because the whole solar system is not staying in one place but is moving throughout the galaxy, and because gravity makes stuff wobble in space as earth, moon, and sun all pull against each other, the pattern of stars visible at specific points of time will change over the course of time.
The stars we see now aren’t in the same place they were thousands of years ago, and they won’t be in the place they currently hold, thousands of years in the future.
The zodiacal constellations have ‘moved backwards’ from where they were first recorded 5000 years ago. This is because of precession — something precedes something else — it comes before it. Virgo precedes Libra; Virgo comes before Libra. So, if the constellations were first recorded with Libra happening on the equinox, and now Virgo happens on the equinox, it has precessed.
The History:
Astrology as we know it in the west started out in Mesopotamia around 3000 B.C., so roughly 5000 years ago. People looked up at the sky and saw that certain events like weather patterns, animal behaviors, seasonal changes, etc. could be tracked by making note of what they saw happening in the night sky.
For example: “Day and night of equal length? Let’s say that group of stars over there is a set of measuring scales.”
BOOM! The constellation of Libra is named at the Autumn Equinox. around 2000 B.C.E. the appearance of the Libra stars (meaning the constellation) immediately before sunrise fit the symbolism indicated the equinox sign of the scales being equal (as documented by cuneiform text Mul.apin I iii 1-2).
At this point in history, the constellations lined up with what was being observed from earth, because constellations were created by people.
People said what a grouping of stars would signify as part of a seasonal clock or calendar.
The origins of astrology are rooted in the observation of cosmic happenings and seeing what they marked as key points in weather and agriculture, and how these matches would fit cultural mythology and experiences on Earth.
Astronomically, the sun entered a certain group of stars, a constellation, on the Vernal (Spring) Equinox. Most sheep farmers would try to have the lambing season at this time so that the lambs would have the lush spring grass to eat after they are weaned. That constellation was called Aries — a ram. So you would schedule the rut for your animals, meaning when you would allow rams and ewes to be together, at certain points in the year so the babies would be born in spring. You would have times marked by things like constellations, to help you keep dates on track and in line.
Other constellations came to take on specific meanings related to religious observances, moments of historical significance, or parts of the cultural mythos that kept people connected to one another through shared beliefs and stories.
And so forth.
Then, a couple of thousand years or so after this recording first began, the constellations had precessed enough to change that alignment. So now instead of seeing the sun lined up in the astronomical constellation of Libra at Autumn Equinox time, we see it in the astronomical constellation Virgo. Likewise, on the Vernal Equinox (around March 20) the sun is in the constellation Pisces.
They shifted backwards along the zodiacal ring and were no longer lined up with their original placements and mythological/cultural/calendrical meanings.
The signs no longer aligning with the constellations meant the Zodiac was splitting into two different calendars. Sidereal (constellation-based) and Tropical (Sun/Earth based). This changing relationship between the two zodiacs (Sidereal and Western Tropical) was documented by Aristarchus of Samos in 280 B.C. Astrologers have known about this phenomenon for thousands of years.
It’s not new.
Into our common era:
Around the 2nd Century AD, Claudius Ptolemy, a really smart guy who knew astronomy, astrology, mathematics, and everything else, said, “This math ain’t mathin’… The constellations are moving about 1 degree ‘backwards’ every 72 years. It doesn’t line up anymore now that we’re seeing harvest at the sun’s time being in Virgo’s constellation.” (Ptolemy, Almagest VII.2.f).
“Let’s go back to saying Libra will mark the date of the Autumn Equinox, because the scales match the concept of the balance of equal day and night at the equinox, despite the constellation itself being in a different place. Make it make sense.” (Ptolemy, Tetrabiblos 1.10f).
In other words: the symbolism and the timing of the seasons matters more than what’s happening with the constellations.
So, now, in this system he essentially got started, known as Western Tropical Astrology, Aries is back to being the sign that starts on the Vernal Equinox (Sun at 0° on the ecliptic – because the ecliptic is an imaginary circle in space, so we can decide what sign is the start anywhere we choose).
And BAM! Libra begins on the autumn equinox (at 180° on the ecliptic), because Ptolemy said so, despite Virgo being the constellation that shows up because Ptolemy wanted to keep the concept of scales matching up with the equal day/night meaning.
Astrology is a geocentric system, meaning it’s taken from the point of view that the Earth is in the center and everything, including the Moon and the Sun, are revolving around it. Ptolemy had this belief, as did many in the ancient world. Despite being wrong about this, as it’s the Earth that revolves around the sun, he still observed that there were points of time when the sun stood still (Solstice) and when the day and night were equal (Equinox) and put those as the points of reference for the zodiac. We know the Earth isn’t the actual center of the solar system, but the astrological view still works because it’s based on observation.
It’s based on how things look from Earth looking up at the sky.
Thus, if you believe that the Earth’s path around the sun, marked off by the solstices/equinoxes and divided by 30° per sign, is your preference of how to calculate this then…
Congratulations! You are a Western Tropical (Ptolemaic) astrologer.
This is why Dr. Tyson says “Scorpios are actually Libras”. Because during the popular Western zodiacal time of Scorpio (Oct. 21-Nov. 21), the sun is actually spotlighting the lovely stars of Libra.
Additionally, mathematically, because the zodiac is a circle, and a circle has 360° degrees, ancient astrologers around 400 B.C. assigned 30° to each sign and it doesn’t matter the size the constellations are in the sky. We’ll call that space the “Sign of _” So the sun, moon, planets, etc. are moving through blocks of space marked off mathematically and not because of the constellation positions or movement. This is because, as they observed, some of the constellations were twice as large as others. Virgo is a big girl and takes about 60° (twice the allotted space for a sign) by herself. So even before Western Tropical Astrology started to get going, Ophiuchus was already out of the game, because 360° divides into 12 cleanly, but not into 13.
Sidereal Astrology — And That Blasted, Annoying Ophiuchus!:
If you believe that the signs should match the dates of the sun being in the different constellations, and that’s how you choose to calculate the zodiac then…
Congratulations! You are a Sidereal astrologer!

This is a different system, a different way of setting up the calendar, and it is subject to change every few hundred years because of precession.
I used to think it was really weird to see calendars that started with Monday instead of Sunday, but in essence, it’s the same principle. You’re still counting out the same days (as in Tuesday precedes Wednesday), and the same number of days. You just choose a different day to say starts the week. Different zodiacal systems are just ways of saying the week starts on Monday instead of Sunday.
Sidereal Astrology is the kind of astrology that uses the stars, single stars or in constellation with one another, to mark the signs. This is what was in use 5000 years ago, because we were lucky enough to have chosen just that time to start noticing certain clusters of stars at different seasonal events, and name them as a constellation relative to what we had going on down here on Earth.
Ophiuchus is a constellation that has significance in some systems of Sidereal Astrology, not in Western Tropical Astrology.
When the matched set of constellation and sign changed, because of the shifting movement of the cosmos (precession), Ptolemy switched it up. Western Tropical Astrology is just a conscious choice to say, “Symbols and seasons matter more to setting this up than the constellations, because the constellations no longer fit the way we calendarized things.”
Because constellations shift.
And we know they shift.
But the timing of the Equinoxes and Solstices does not change. “Those will be the point of reference,” said Ptolemy.
This is why I say that astrologers have ALWAYS known about this stuff. You don’t watch the sky for thousands of years and not see this happening. 
The signs in Western Astrology are just sections of space in the sky, not the area of the constellations themselves.
It’s all math and geometry and measurement and calculations.
Because Ptolemy liked things neat and organized.
This system doesn’t use the constellations for anything other than the same names and historical/seasonal/mythological/cultural meaning given to them.
This means there are 12 signs in the zodiac according to Ptolemy’s calculations (not 13 — sorry, not sorry, Ophiuchus). And, because his calculations fit better and are the most organized, they are what has become the predominant system of Astrology in the western world.
12 signs divides up so nicely in astrology:
4 elements (earth, air, fire, water)
4 functional houses (individual, temporal, relative, terminal)
3 quadruplicities (cardinal, fixed, mutable)
3 types of modal houses (angular, succedent, cadent)
2 polarities (masculine, feminine)
and 6 pairs of opposites.
Neat and tidy.
Dr. Tyson’s science is immaculately correct, but that’s not what he’s getting wrong. Mixing parts of Sidereal (using constellations) with parts of Western (12 signs based on Ptolemy’s calculations and assessments), is incorrect, and that’s why your sign hasn’t changed.
I’m a Western Tropical Astrologer.
So, my zodiac sign is Gemini. In the Sidereal Zodiac, I’m a Taurus. In the Chinese Zodiac, I’m a Snake. In the Celtic Tree Zodiac, I’m a Hawthorn… Etc. Etc.
I’m all of them. It just matters which system I’m using and what horoscope I’m going to read.
And none of those zodiacs is going to change or replace what I am in the others.




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