AstroLibrary 🔎
Daily Personalized Horoscope ↗

Ophiuchus is Not the 13th Zodiac Sign

Sidney Hall - Urania's Mirror, Ophiuchus holding serpent

Updated January 2, 2017
Originally posted August 10, 2015
By Corinne Lane     8 Comments

We have 12 zodiac signs, not because there are 12 constellations along the ecliptic, but rather for the same reason that we have 12 months: because there are 12 lunar cycles for each solar cycle.

In other words, the sun takes one year to travel once completely along the ecliptic path. During that time, the moon travels the ecliptic 12 times. Ancient astronomers in Babylon designated the 12 signs of astrology after meticulous observation of these cycles.

Some are quick to assume that the Ophiuchus constellation is actually a 13th zodiac sign, but they are wrong. They erroneously claim (without much knowledge of astrology) that since the Ophiuchus constellation is along the ecliptic, that Ophiuchus must be the 13th zodiac sign.

But, there are as many as 22 star constellations along the ecliptic band. The number of constellations does not change our zodiac signs. Our zodiac signs are calculated by the Earth’s solar seasons and lunar months, not by the number of arbitrarily-designated constellations. The zodiac signs are 30-degree sections of space along the ecliptic band.

The popular 12 star constellations, with their varying degrees and sizes, are not the actual zodiac signs. These 12 constellations were named after the zodiac signs they represent, not the other way around!

Image Credit: Sidney Hall [Public domain], via Wikimedia Commons

See more About Real Astrology
See more
Go to Blog main page


  1. It’s hard to accept your otherwise well thought-out and very attractive site when you are still using tropical astrology! The romans institutionalized ptolemy’s errors as regards the precession, so the variance with reality (galactic time or IUA degrees, used by NASA and all astronomers) in your calculations is catastrophic. Also, since when can the universe be divided into neat 30 degree segments? I admire your attempts at understanding astrology, but you are way, way off when it comes to astronomy, which of course is the basis of all astrology. The actual number of zodiac signs may be in dispute, but you’re cementing a system which omits women and has been used to pillory women and persecute them over the centuries, in spite of the fact that women probably developed it, using the lunar calendar. I think you give short rift to the observable universe, and instead, by accepting a ptolemic view, you carry on the mistakes of the past. I hope you one day join us.

    • Astrology Library on said:

      The Tropical Zodiac is intimately aligned with our Earth’s 4 seasons. The Tropical Zodiac is perfectly aligned with our Spring Equinox, which makes it accurate for us here on Earth. The Sidereal Zodiac is not as accurate because it does not align with our Earth’s seasons. Everything is relative. To an ant, a tree is “up above,” but from an airplane, a tree is “down below.” Likewise, to us on Earth, the Tropical Zodiac which is aligned with our seasons is the most accurate. See The Tropical Zodiac is Not Misaligned for more info.

  2. Astrology, in general, is so errored that it is very hard to even contemplate it, even in relation to the ancient intentions for which it originally held. Due to the fallibility of ancient identification of correct constellation alignments, and precession which has caused a complete ‘sign change’ that is unrecognized in modern times, we stare at the calendar on October 1 and wrongly assume that we are ‘in Libra’, when in fact, we are near-centered in a sunrise nearly centered in Virgo. This massive error not only leads to misinterpreted ‘birth signs’, but in people professing deep astrological ‘symbolic knowledge’ all the while not even recognizing that the ‘driving forces’ of ‘birth signs’, natal charts, etc., are in fact, as flawed as trying to use a 1901 road map to navigate modern-day Manhattan. Since Astrology as a ‘pseudo-science’ fails to correct this massive error, how can anyone take it seriously as anything more than ‘mere art’? Sadly, if ‘birth signs’ do have any value, or if ancient prophecies are keyed to astronomical events identified in astrological metaphors, how would anyone (maybe 1-in-1,000,000) ever be able to deduce that ‘the Woman’ of Revelation 12 is in fact Virgo, or that it was trying to set a ‘date’ of when an event would happen, or that ‘Draco’ is the dragon, etc.? Hard to be ‘predictive’ of a date, when you can’t even hit the right month.

    • Astrology Library on said:

      Hi. We actually are in Libra on October 1. It’s not wrong, as you say, but rather it is the Tropical Zodiac that puts us in Libra, while the Sidereal Zodiac is in Virgo. Those 2 zodiacs are based on 2 different reference points. The Sidereal is based off of the backdrop of the stars, while the Tropical Zodiac is aligned with our Earth’s seasons. The Tropical Zodiac is perfectly aligned for us because it’s aligned with our Spring Equinox. To say that our Tropical Zodiac is incorrectly aligned is to say that Spring is late every year. See The Tropical Zodiac is Not Misaligned.

      • Zedaya Figueroa on said:

        But are seasons are arriving at odd times. Birds started migrating back this year in late February, but according to the standard accepted calender the Spring equinox is on March 20. That’s an entire month difference. There is undeniable evidence of procession.

  3. Ronald on said:

    Ophiuchus has been around the astral sky for over 3,000 years. Proposed by scientists 40 yrs ago to be included in the zodaic. No one claimed to be born under these dates (30 Nov – 17 Dec) can proudly call themselves ‘serpent bearers’.
    The original zodaic has 12 signs aligned perfectly within 12 months. So Ophiuchus is more than just science fiction to bring confusion to innocent humans. Even Jesus had 12 disciples. The 13th zodaic is the devil.

  4. And about the 13th sign of the zodiac, I can say the following, people confuse astrology with astronomy. What does this mean? This means that even if the stars have shifted, it shouldn’t relate to the sphere of the Zodiac and Zodiac signs in any case. To put it simply, even though Ophiuchus exists, it is merely a constellation that has nothing to do with the Zodiac signs.

    • Kim Lovelace on said:

      Are we not talking about the energy of the Planets In Signs here? How is Astrology not related to Astronomy? It is the Western Tropical Astrology that confuses everyone because it is based on a manmade fixed map that was created in the Age of Aries. It was created for more seasonal & agricultural reasons, not for Astrology, by that point Astrology was Just an afterthought. Ptolemy knew that the Constellation Ophiuchus sat on the Ecliptic, the path of the Sun but chose to ignore it. His system was very clever, but it’s significance is becoming more and more out of date. Especially since we are coming to the end of the age of Pisces!

      Western astrology makes me laugh because you still take into account astronomical events like eclipses & retrogrades, but want to apply them to an old outdated system. So really Western astrological is not only confusing, it’s hypocritical!

      Much Love

      Even the Tropics of Capricorn & Cancer are out of date!!!

Your thoughts are welcome: Cancel reply

Your email address will not be published.

Top   ↑