You might think you have a good grasp on the night sky. You can find Polaris, you’re familiar with Orion; you’ve checked out the Pleiades, and you’ve stared up at the Summer Triangle.
To be perfectly clear: a constellation isn’t a “real” thing, in the way that a cheesecake or a nebula is a real, physical thing. It is a human designation, a term we invented so we could group stellar objects together in a way that made sense for our eyes. The stars in a constellation aren’t like the cities in a country; they are not physically near one another. They only appear close from our faraway distance.
We can think of constellations in two ways. First, like tags in the Dewey Decimal System: They help us find things. They divide up space. We can say “Orion,” and know what direction to point our telescopes in. But we can also think of constellations in the romantic sense. They’re our collective memories of the universe. They’re the stories of our ancestors, projected in the heavens above us. They remind us that the observer and the observed are always interconnected, and in that connection lies something truly magnificent.
But if you’re a North American observer, you’ve only ever really seen half of what the night sky has to show. South of the equator lies the expansive Southern Sky, where the keen-eyed observer can see huge swaths of the Milky Way, two of our closest neighboring galaxies, and an incredible array of stellar marvels. Below, we dive into 11 constellations in the Southern Hemisphere you should know.
Crux, the Southern Cross, is small but mighty. It points the way to the Southern Pole; follow its lead to find Octans. The constellation is home to the Coal Sack nebula, quite possibly the most famous dark nebula in the sky. Crux also holds the 12th brightest star in the sky, Acrux, and hosts its very own meteor shower, the Crucids. The cluster NGC 4755, nicknamed the Jewel Box, is not only beautiful—astronomer John Herschel called it a “superb piece of fancy jewelry”— it’s also one of the youngest and brightest clusters in the sky. Crux holds all that and a drink, too; its beta star is Mimosa, delightfully enough.
Visually, Octans is not a particularly stunning constellation. Its brightest star is Nu Octantis, which, at a magnitude 3.8, isn’t really all that bright. Nu Octantis is so dim that astronomers think it might not actually be a star at all, but instead, a giant planet. Nevertheless, you’ll want to tick Octans off your list when you go stargazing in the Southern Hemisphere—Octans is home to the Southern Celestial Pole. There’s no handy Polaris-like star in the Southern Hemisphere to mark the point for you, so the dedicated observer must learn to puzzle out the shape of Octans instead, finding their way there by following Crux’s pointer. It’s worth the effort to know the celestial pole’s location, though: It’s the point around which all your observations will revolve!
The northern sky is full of legends and heroes: Hercules, Perseus, Andromeda. The southern sky, well, it has Musca. The fly.
When we refer to “official” constellations today, we’re talking about the 88 constellations designated by the International Astronomical Union, or IAU. For the most part, the IAU leans on the names Europeans gave to constellations. Europeans were observing the Northern Sky thousands of years ago, so their Northern names are historic, meaningful, and epic. They only got to the Southern Sky in the last 500 or so years, so while people native to the Southern Hemisphere have beautiful names for the stars they knew, Europeans mostly pulled whatever names they could find out of a prosaic hat. One man, Nicolas Louis de Lacaille, personally named more than a dozen of the 88 of the constellations. His taste leaned more toward the earthy, less toward the mythological. Musca is home to a few 10th and 11th magnitude clusters and such, but mostly, we recommend you check it out for the humor of its humble name.
4. Microscopium (and Telescopium)
The ancients wove their gods and heroes, icons and idols into the constellations. Nicolas Louis de Lacaille, who brought us Musca, projected his own objects of worship into the sky. Lacaille, however, was an enlightenment scientist, so where ancient astronomers like Ptolemy found fascination in the myths, Lacaille worshipped the tools of science. That’s how Microscopium and Telescopium came to be immortalized in the heavens. What better objects to gaze on than the crowning tools of science?
Quite the opposite of Microsopium and Telescopium, Eridanus was actually known to and named by ancient Northern Hemispheric observers. Its name, Eridanus the River, is attributed to Ptolemy. Eridanus was associated with the rivers of many ancient cultures, from the Nile to the Po, and from the Tigris to the Euphrates. The Greeks associated Eridanus with the legend of Phaeton, the son of the sun god. One day, Phaeton’s father granted his son’s deepest desire: to drive his father’s chariot. But alas, the chariot was more than Phaeton could handle. After his poor driving of the sun set fire to the heavens and froze over the Earth, Zeus struck Phaeton down in anger, and he tumbled out of the sky, headfirst into the winding, sacred river Eridanus. Lit up by the burning chariot, Eridanus has glimmered in the sky ever since.
Tucana was named after the toucan; through binoculars or a telescope, it can appear just as colorful and mesmerizing as that aviary giant. Tucana is home to the Small Magellanic Cloud, which, along with the Large Magellanic Cloud, is named after after the explorer Ferdinand Magellan; one of our first written accounts of their observation comes from his 16th-century voyage. But humans have been recording and marveling at the Magellanic Clouds for millennia. Chileans drew them in petroglyphs, and Indigenous Australians told of them in their oral histories. The Magellanic Clouds’ visual beauty alone explains our fascination with them, but scientifically, they are also rich sources of galactic inquiry for modern-day astronomers. Both Magellanic Clouds are dwarf galaxies that orbit our Milky Way, and will do so until our galaxy eventually consumes them whole, sometime in the next few billion years.
Following Tucana we have Dorado, the Dolphinfish, home to (most of) the Large Magellanic Cloud. Within Dorado’s luminescent Large Magellanic Cloud, the keen-eyed observer can find the Tarantula Nebula, the “most luminous nebula of its type in the local universe.” It’s gigantic, spanning 1000 light years from end to end, and is a busy, busy place. The Tarantula Nebula is a highly active star-forming nebula, bringing new life into this universe at an impressive rate. So turn your binoculars away from Lady Gaga and toward the constellation Dorado to truly witness how a star is born.
The constellations Vela, Carina, and Puppis all have oddly nautically themed Latin names that don’t really make sense without their backstory. Vela is the sail, Carina is the keel, and Puppis is the poop deck; together, the three comprised the massive constellation Argo Navis, named after the Greek hero Jason’s ship, the Argonaut. Unfortunately, Argo Navis was ridiculously large in the sky—and not all that useful for astronomers—so they chopped it into pieces in the mid-1800s. Today’s Vela is a perfectly respectable target for a field astronomer with a good pair of binoculars, but it can easily trip up the inexperienced stargazer, as two of its stars make up a foursome known as the “False Cross.” This is not the Southern Cross—it’s simply a trickster.
But Vela holds true wonders as well as false promises. The Vela Supercluster centers on the area of the constellation Vela. It was only discovered in the last decade, and astronomers say it’s one of the largest known structures in the universe. It's a massive group of galactic clusters, a truly dizzying sentence when you stop to process the scale of its subject. Make sure your feet are planted on firm ground when you’re looking at Vela, lest its wonders make you dizzy, too.
Carina, the keel, is home to the mysterious Eta Carinae nebula. Something strange happened to the Eta Carinae system about 150 years ago. It released a supernova-like amount of energy, exploding in the sky—but technically, it did not actually supernova. It is, according to Astronomy Now, “the star that will not die.” Astronomers don't know what happened to Eta Carinae, but they've have taken some truly incredible pictures of it nevertheless. Even with the naked eye, Eta Carinae can be discerned as a bright “knot” in the Milky Way, and with humble field binoculars, an observer can make out its distinctive structure. And who knows: Astronomers think that one day soon, the central star may actually supernova. For real, this time.
The constellation Carina is also where Canopus, the brightest star in the Southern Sky, can be found. You won’t want to miss it, and, you really won’t be able to anyhow.
You can’t swing by Vela and Carina without stopping to visit Puppis, too. Puppis, the poop deck of Argo Navis, is chock-full of deep sky objects cataloged by French astronomer Charles Messier. Called Messier objects, they can range from clusters to galaxies to nebulae, but they’re all incredible targets for the amateur astronomer. M46 (Messier Object 46) and M47 (you see how this goes) are an especially lovely pair of open clusters to see in binoculars or telescopes. Puppis’s brightest star, Naos, or Zeta Puppis, is actually one of the hottest stars in the entire Milky Way, a blue supergiant with 60,000 times the luminosity of our own sun.
Centaurus is home to our three nearest stellar neighbors, the triple star system of Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. If your Latin is good, it won’t surprise you to hear that Proxima Centauri is technically the closest star in this system to our very own sun, at 4.25 light years away. However, Alpha Centauri A and B shine brighter in our sky, due to their comparatively greater stellar magnitudes (inherent brightness). At an apparent magnitude of -.27, Alpha Centauri is the third brightest star in the sky to a human observer. If someone tells you that Rigel Kentaurus is actually the third brightest star in the sky, you don’t need to correct them, because that’s actually just another name for Alpha Centauri.