Libra Constellation: The Scales of the Zodiac
We have everything you need to know about the Libra Constellation, and the biggest surprise may be that you are not pronouncing it correctly!
Quick Reference: The Libra Constellation
- What it is: Libra, the Scales, the only zodiac constellation that pictures an object, not a person or an animal.
- Named stars: Zubeneschamali, “The Northern Claw,” and Zubenelgenubi, “The Southern Claw,” once the claws of Scorpius.
- Look for: Zubenelgenubi, an easy double star to split with binoculars.
- Green star: Zubeneschamali may be the only naked-eye star that looks green.
- Say it right: LY-bra, not LEE-bra.
The Libra constellation, the Scales, is the only one of the twelve zodiacal constellations that does not stand for a person or an animal. It is well known in the zodiac but not much to look at, an oblong figure of stars laid out like a beam with two pans hanging from it for weighing. Look closely and the balance is tilted, because the load in the right-hand pan sits heavier than the load in the left. What the Scales lack in brightness they make up for in story: a pair of stars borrowed from the Scorpion, one star that may glow faintly green, and a name that plenty of folks say wrong. Here is how the pattern came to be, what its star names mean, and how to pronounce Libra the right way.
How the Libra Constellation Came to Be
One early telling of how the Libra constellation came to be holds that the Scales stood for the equality of day and night. That balance fit the season, because when the Sun was entering this constellation some 3,500 years ago, the autumnal equinox took place in Libra. These days the equinox happens next door in Virgo instead.
The reason the equinox point drifted is a slow wobble in the Earth’s axis that astronomers call precession. Over roughly 26,000 years the axis traces a wide circle in the sky, which shifts the background stars behind the Sun little by little. In the centuries since Libra held the equinox, that drift carried the crossing westward into Virgo, and it will keep on moving. The old name, the Scales, still remembers the time when day and night hung in perfect balance right here.
Scorpion’s Claws: The Named Stars of Libra
Open an old star atlas and you will find the stars of Libra doing double duty. Ancient charts of the neighboring constellation Scorpius reached over and borrowed them to form the Scorpion’s claws, and that history is preserved in their names. Zubeneschamali comes from the old Arabic for “The Northern Claw,” and Zubenelgenubi means “The Southern Claw.” Today, by international agreement, the two constellations are strictly divided. Even so, these two stars no longer belong to Scorpius and yet kept their old claw names as members of Libra.
Zubenelgenubi, the Southern Claw, is an easy double star to split with a pair of binoculars, which makes it a fine target on a clear night. On August 16, 2018, the planet Jupiter passed north of this third magnitude star, closing to about half the distance it had sat at just over one degree to the northwest a short while before. Bright planets keep wandering through this stretch of the zodiac, so it is worth checking where they are before you head out. NASA’s monthly skywatching guide is a plain-English way to see which planets are visiting Libra and the rest of the sky.
The other claw, Zubeneschamali, is the odder of the pair. This third magnitude star looks plain whitish to some observers, yet others have described it as possessing a “beautiful pale green” hue. If they are right, it may be the only naked-eye star that shows green to human sight, which is a claim worth testing yourself on a dark, clear night. Pick an evening when the Moon is not washing out the fainter stars, and our full Moon dates and times will tell you which nights stay dark enough.
If the Scales do not leap out at you, you are in good company, because plenty of star patterns do not really look like anything. Give your eyes about 20 minutes to adjust to the dark, then trace the low, boxy shape between Virgo and Scorpius and let the balance settle into place.
How Do You Pronounce Libra?
Once you can find Libra, be sure you can say it. The lesson once came at New York’s Hayden Planetarium, where a senior lecturer sitting in the audience corrected a young presenter after one of his first sky shows. “Always remember,” he said, “You pronounce it Ly-bra, not Lee-bra. If you want to borrow a book, you go to a Ly-brary, not a Lee-brary!”
The correction was hard to swallow at first. The lecturer, Harold Parnham, was also a professor of navigation at the State University of New York at Fort Schuyler in the Bronx. The doubt seemed fair, too, since the word library traces back to the Latin “libraria,” meaning book, while Libra is Latin for “balance.” Two different roots, two different words.
A little checking settled the matter. The World Book Encyclopedia (Field Enterprises Educational Corporation) gave the pronunciation as LY-bruh, while The American Heritage Dictionary of the English Language (Houghton Mifflin Company) accepts both the LY and the LEE versions. And in the classic star guide by H.A. Rey, The Stars: A New Way to See Them, the index lands in the same place: SCALES, LIBRA (LY-bra), const. in zodiac.
Libra in the Zodiac and the Best Days
As a sign of the zodiac, Libra runs from about September 23 to October 23, the weeks that open with the autumnal equinox and the balance of day and night. The Farmers’ Almanac follows the Moon as it passes through Libra and the other eleven signs, and that path is the backbone of our Best Days Calendar, a plain planning tool for timing everyday chores by the sign the Moon is in.
Write anything uncomplimentary about a person’s sign and you may hear about it. Years ago, after one of these Libra notes ran on the online news service Space.com, this email arrived: “You’ve got some helluva nerve saying Libra is not much to look at! My wife is a Libra! Watch it, buster, or she will become unbalanced.” All scale that end scale. Faint pattern or not, Libra keeps its hold on the folks born under it, and on anyone who likes to know the story behind the stars. Step outside on the next clear night, find the Scales for yourself, and decide what you make of them.
The Libra Constellation: Frequently Asked Questions
What is the Libra constellation?
Libra, the Scales, is one of the twelve zodiacal constellations, and the only one that pictures an object rather than a person or an animal. It is an oblong figure of stars set out like a beam with two weighing pans, tilted so the right-hand pan sits lower. It is well known in the zodiac but faint in the sky, which is why it takes a little patience to find.
What are Zubeneschamali and Zubenelgenubi?
They are the two brightest stars of Libra, and their names come from the old Arabic for “The Northern Claw” and “The Southern Claw.” Ancient star atlases counted them as the claws of the neighboring constellation Scorpius. The two constellations are strictly divided today by international agreement, but the stars kept their old claw names as members of Libra.
Is the star Zubeneschamali really green?
Maybe. This third magnitude star looks plain whitish to some observers, while others have described it as a “beautiful pale green.” If those reports are right, it may be the only naked-eye star that shows green to human sight. It is a claim worth testing yourself on a dark, clear night.
How do you pronounce Libra?
Say it LY-bra, not LEE-bra, the same long-I sound you use in “library.” The World Book Encyclopedia gives it as LY-bruh, and The American Heritage Dictionary accepts both the LY and the LEE versions. The classic star guide by H.A. Rey, The Stars: A New Way to See Them, lists it as LY-bra as well.
Why is Libra the only zodiac sign that is not a person or animal?
Of the twelve zodiacal constellations, only Libra pictures an object, the Scales. One early telling says the Scales stood for the equality of day and night, because when the Sun entered this constellation some 3,500 years ago, the autumnal equinox fell in Libra. The name kept the idea of balance even after the equinox point drifted into Virgo.
What are the dates of the Libra zodiac sign?
As a sign of the zodiac, Libra runs from about September 23 to October 23, the weeks that begin with the autumnal equinox. Those dates trace back to a time when the Sun crossed the equinox point within the Scales. The Farmers’ Almanac follows the Moon through Libra and the other signs in its Best Days Calendar to help you plan everyday tasks.
Joe Rao
Joe Rao is an esteemed astronomer who writes for Space.com, Sky & Telescope, and Natural History Magazine. Mr. Rao is a regular contributor to the Farmers' Almanacand serves as an associate lecturer for the Hayden Planetarium in New York City.
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I’m a Lybra. Lol.