The 12 Zodiac Constellations

For thousands of years, people have looked toward the same band of sky and recognized the familiar constellations of the zodiac: Aries, Taurus, Gemini and the other star patterns that make up the traditional zodiac.

In astronomy, these constellations are linked by their position along the path the Sun appears to follow across the sky during the year. But the astronomical zodiac isn’t quite as neat as the familiar system of 12 signs. The constellations are different sizes, their boundaries don’t match traditional zodiac dates and, perhaps most surprisingly, the Sun actually passes through 13 constellations rather than 12.

The 12 Zodiac Constellations in Order

The 12 zodiac constellations are traditionally listed starting with Aries and ending with Pisces. Aries comes first because the traditional starting point of the zodiac is the March equinox — the point each spring when the Sun crosses the celestial equator and Northern Hemisphere spring begins.

When this system took shape, the March equinox occurred while the Sun appeared against the stars of Aries. Aries therefore marked the beginning of the zodiac, and the equinox became known as the “First Point of Aries.” Precession has since shifted the equinox westward against the background stars, so today it lies in Pisces rather than Aries — but the traditional name and Aries-first ordering remain.

From Aries, the sequence continues through Taurus, Gemini and the remaining zodiac constellations. Each represents a figure or object inherited from the traditions that shaped the zodiac, from Aries the Ram to Pisces the Fishes.

These constellations don’t form a circle of stars physically surrounding the Solar System. They lie at vastly different distances from Earth and only appear in the same broad region of our sky. What connects them is something much closer to home: Earth’s orbit around the Sun.

What Makes a Constellation Part of the Zodiac?

As Earth travels around the Sun, our viewing direction into space gradually changes. From Earth, this makes the Sun appear to move against the background stars, completing one circuit of the sky over the course of a year.

This apparent path is called the ecliptic.

The constellations through which the ecliptic passes make up the astronomical zodiac. At different times of year, the Sun therefore appears in front of different zodiac constellations—not because the Sun is moving among those distant stars, but because Earth has moved to a different position in its orbit.

The Moon and planets also tend to appear in or near this same band of sky. That’s because the major planets orbit the Sun in roughly the same plane as Earth, although their paths don’t follow the ecliptic exactly.

Why Are There 12 Zodiac Constellations — But the Sun Passes Through 13?

Astronomers recognize 88 official constellations, each with fixed, non-overlapping boundaries set by the International Astronomical Union. The zodiac constellations are simply the ones that happen to lie along the ecliptic — the Sun’s apparent path across the sky over the course of a year.

Trace that path through the modern boundaries, though, and something unexpected happens. We traditionally speak of 12 zodiac constellations, but the ecliptic actually threads through 13.

When the ecliptic is traced through those modern boundaries, it doesn’t pass through only the familiar twelve. Between Scorpius and Sagittarius it also crosses Ophiuchus, the Serpent Bearer.

Ophiuchus isn’t a newly discovered constellation. It has been known since antiquity and was one of the 48 constellations catalogued by the Greek astronomer Ptolemy in the second century AD. Nor does it mean astrology has quietly gained a 13th sign — the traditional zodiac still has 12. The apparent contradiction only arises from treating zodiac constellations and zodiac signs as if they were the same thing. They aren’t.

Zodiac Constellations vs. Zodiac Signs

The familiar names Aries, Taurus, Gemini and so on are used both for astronomical constellations and astrological signs, but the two systems divide the sky very differently. One name even differs slightly: astronomers call the constellation Scorpius, while the corresponding astrological sign is called Scorpio.

Astrology divides the zodiac into 12 equal sections of 30 degrees each, giving every sign the same share of a 360-degree circle. In the Western astrological system, the signs are defined by these 12 equal divisions rather than by the modern boundaries of the constellations that share their names. Real constellations aren’t arranged so conveniently—some stretch across a much larger portion of the ecliptic than others. That’s why the traditional dates associated with the zodiac signs shouldn’t be confused with the dates the Sun is actually inside the corresponding astronomical constellation.

Cancer provides a good example. The astrological sign of Cancer begins at the June solstice, around June 21, but the Sun doesn’t enter the modern astronomical boundaries of the constellation Cancer until around July 21 — roughly a month later.

There’s a second reason the two systems have moved further out of alignment over time: precession. Earth’s rotational axis slowly changes direction over a cycle lasting roughly 26,000 years, causing the positions of the equinoxes and solstices to gradually shift against the background stars. Around two thousand years ago, the March equinox lay in Aries. Today, it lies in Pisces.

The zodiac signs remain fixed to the seasons, while their alignment with their namesake constellations gradually changes over time.

What’s the difference between astronomy and astrology? →

The difference between equal signs and irregular constellations produces an especially striking result: the Sun doesn’t spend anything close to the same amount of time in each constellation.

When Does the Sun Pass Through Each Zodiac Constellation?

As Earth moves around its orbit, the Sun appears to travel through each of the following 13 constellation regions. The dates are very different from the familiar astrological sign dates.

Find your birthday in the table and you may discover that the Sun appears in a different constellation from the zodiac sign traditionally associated with that date.

Dates are approximate and can vary slightly from year to year. They refer to the Sun’s position within modern astronomical constellation boundaries, not traditional astrological sign dates.

The contrast between Virgo and Scorpius shows just how unequal the real constellations are. The Sun takes roughly a month and a half to cross Virgo but spends less than a week within the boundaries of Scorpius before moving into Ophiuchus. That difference would be impossible in the astrological system, where every sign occupies exactly 30 degrees of the zodiac.

The table also reveals something useful for anyone hoping to see these constellations. If the Sun is currently passing through one of them, that’s generally the wrong time of year to look for it at night.

How to See the Zodiac Constellations

When the Sun appears within a zodiac constellation, that constellation lies in roughly the same direction in the sky as the Sun. Its stars are still there, but they’re overwhelmed by daylight. At night, when your side of Earth is facing away from the Sun, you’re also looking away from that part of the sky. As Earth continues around its orbit, the constellation appears progressively farther from the Sun in our sky, eventually becoming easier to see in the evening.

This is why the constellation actually behind the Sun on your birthday will generally be difficult or impossible to see in the night sky around that time of year.

The easiest way to start recognizing the zodiac is to use a few distinctive patterns as landmarks. Which ones are easiest depends on your location and the season, but several stand out particularly well.

For Northern Hemisphere observers, Taurus is prominent on winter evenings and can be found using nearby Orion. Follow the line of Orion’s Belt toward the reddish star Aldebaran, which appears against the V-shaped Hyades cluster and marks the eye of the Bull. Leo becomes prominent on spring evenings and can be recognized by the curved Sickle of stars, with its brightest star, Regulus, at the base.

Scorpius and Sagittarius are prominent around the middle of the year for observers in the Southern Hemisphere and at low northern latitudes. Scorpius has a distinctive hooked shape centered on the bright reddish star Antares, while nearby Sagittarius contains the easily recognized Teapot asterism against the rich star fields of the Milky Way.

Exactly which zodiac constellations you can see—and how high they rise—depends on your latitude, the season and the time of night. You don’t need to learn them all at once. Find one recognizable pattern, learn the constellations around it, and gradually follow the zodiac across the sky.

Explore constellations by season: Winter | Spring | Summer | Autumn

Explore all 88 constellations →

Frequently Asked Questions

What are the 12 zodiac constellations?

The 12 traditional zodiac constellations are Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius and Pisces. They lie along the ecliptic, the apparent path the Sun follows against the background stars during the year.

Are there 12 or 13 zodiac constellations?

Traditionally, we speak of 12 zodiac constellations, but the Sun actually appears to pass through 13 of the 88 modern constellation regions over the course of a year. The additional constellation is Ophiuchus, the Serpent Bearer, which lies along the ecliptic between Scorpius and Sagittarius. Ophiuchus is an astronomical constellation, not a 13th astrological sign.

Are zodiac signs and zodiac constellations the same thing?

No. In Western astrology, the zodiac is divided into 12 equal signs of 30 degrees each. Astronomical constellations are irregular regions of the sky with different sizes and boundaries. The two systems therefore don’t divide the zodiac in the same way.

Why doesn’t my zodiac sign match the constellation the Sun is actually in?

There are two separate reasons. First, astrological signs divide the zodiac into 12 equal 30-degree sections, while astronomical constellations have irregular boundaries and very different sizes — so the dates never lined up precisely to begin with. Second, precession has slowly shifted the seasonal points of the zodiac against the background stars over thousands of years, pulling the two systems even further apart. Between the two, the constellation behind the Sun on your birthday can easily carry a different name from your zodiac sign.

Can you see your zodiac constellation on your birthday?

If you mean the constellation actually behind the Sun on your birthday, usually not. It lies in roughly the same direction in the sky as the Sun, so its stars are overwhelmed by daylight during the day — and at night, your side of Earth is facing away from the Sun and that constellation too. It only becomes easy to see once Earth has moved further around its orbit, months later.

What do the 12 zodiac constellations represent?

The traditional constellations represent Aries the Ram, Taurus the Bull, Gemini the Twins, Cancer the Crab, Leo the Lion, Virgo the Maiden, Libra the Scales, Scorpius the Scorpion, Sagittarius the Archer, Capricornus the Sea Goat, Aquarius the Water Bearer and Pisces the Fishes.