Lifestyle Astrology The Truth Behind the '13th Zodiac Sign', Ophiuchus Here's what you need to know about the buzzy, so-called "forgotten constellation" of the zodiac. By Maressa Brown Maressa Brown Instagram Twitter Website Maressa Brown is a journalist and astrologer who's a regular lifestyle contributor and resident astrologer for InStyle. She has nearly two decades of professional experience writing, reporting, and editing lifestyle content for a variety of digital and print consumer-facing publications including Parents, Shape, Astrology.com, and more. InStyle's editorial guidelines Published on January 28, 2022 @ 09:00AM Pin Share Tweet Email Photo: Stocksy Whether you're a total astrology nerd or a beginner, you likely know that the date you were born determines your sun sign. If you were born on August 3, you're a Leo. December 4? Sag. But every now and then, all hell breaks loose over a viral story that proclaims you're no longer the zodiac sign you thought you were, because there's a 13th sign — Ophiuchus — that has changed everything you thought you knew about astrology. Yet, this is a myth that requires busting time and time again. Here's what you need to know about Ophiuchus. How Western Astrology Works To understand the confusion around Ophiuchus, it's helpful to know the difference between the Tropical zodiac (aka Western astrology) and the sidereal zodiac. Tropical Zodiac Created by Ptolemy, a Greek mathematician, astronomer, and the father of modern astrology, this system is based on a permanent, fixed astrological map, based on where the constellations were back around 0 AD. The system involves dividing the ecliptic — aka the sun's apparent path around the Earth — into 12 equal segments, each made up of 30 degrees. This system of astrology named the signs of the zodiac after the constellations that come up along the ecliptic, but they're not tied to their positions. According to Nicholas Campion's A History of Western Astrology. Vol. I, "[Ptolemy's] definition, whether by intent or through a misunderstanding of the zodiac as beginning with the sun's location on the spring equinox, was to cause problems in the future because, by tying the zodiac to the seasons, he cut its ties to the stars, which gradually moved away from the signs." Western astrology is also meant to reflect our experience of the seasons. So the first day of spring is always tied to the first day of a whole new cycle for the sun through the 12 signs. The spring equinox marks the first day of Aries, the first sign in the tropical zodiac. Sidereal Zodiac Followed by ancient cultures like the Vedics and Mayans, this form of astrology still uses signs that are based on the names of the constellations. However, it also relies on the current, modern position of the constellations as opposed to a set system. Sidereal astrology is used by Vedic astrologers in India or within the Hindu faith. What Ophiuchus Is and Is Not In 1930, the International Astronomical Union defined the constellation boundaries of Ophiuchus, noting that the sun passes in front of it between November 29 and December 18. And every now and then, churning up a whole new wave of chatter, drama, and skepticism about astrology, astronomers point this out. While neither system of astrology officially uses Ophiuchus as a sign, some sidereal astrologers may incorporate it into their practice. The constellation, which represents a serpent-bearer, falls between the late degrees of fixed water sign Scorpio and the earlier degrees of mutable fire sign Sagittarius. And in Greek mythology, Ophiuchus represents the god of medicine, Asclepius, son of the god Apollo, who was known to have great healing powers and intellectual strength. So sidereal astrologers who use the sign would say someone who was born between November 29 and December 18 might have the intuition of a Scorpio and the thirst for knowledge of a Sagittarius. As for western astrologers though, Ophiuchus doesn't come into play in our practice. Why There's No '13th Zodiac Sign' Whether you'd prefer to use the tropical or sidereal system, both have been in place for thousands of years and utilize a harmonious system based on 12 signs. With 12 signs, we get three signs per season, each reflecting our experience of that part of the season. Aries kicks off the party as the first sign, and Pisces wraps it all up with its infinite emotional intelligence and spiritual wisdom. The signs sit opposite from one another to create polarities (sometimes referred to as "sister signs") that show us how two very different perspectives — for instance, Leo's self-focus versus Aquarius' community-oriented view — can serve as two sides of the same coin. In other words, ancient astrologers created a geocentric, interpretive system that's meant to reflect our experience of time and the seasons. And if you have a thirst for more knowledge about your personal astrology, the best way to understand more is by unpacking your natal, or birth, chart. By seeing the wheel, divided into 12 houses, each made up of 30 degrees, the beauty of a time-honored system becomes even more clear. And once you get in the weeds with it and begin to wrap your head around the many layers of intel it has to provide, it becomes even more abundantly clear that everything about the astrological system that has been in place for thousands of years is perfectly in balance just as it is — no 13th sign required.