Scorpius, the spectacular scorpion

The fabulous cosmic scorpion that scuttles across our winter sky contains some fabulous binocular treasures

The gorgeous star chart of Scorpius by Dr. John Bevis (1695-1771)

In Greek mythology, Scorpius is the scorpion that was sent by the earth goddess Gaia to kill Orion, the legendary hunter of exceptional skill and strength. Orion had boasted that he could kill every animal on Earth, and this so angered Gaia that the scorpion was dispatched to do his deadly deed.

After Orion’s death, the gods placed him and the scorpion in the night sky, but on opposite sides of the celestial sphere so that Orion wouldn’t have to share the sky with the scorpion that had killed him.

But in actual fact, Scorpius pre-dates the Greeks, and is one of the oldest constellations known. The Sumerians called it GIR-TAB, or “the scorpion,” about 5,000 years ago. (It is worth noting that the name of this constellation is Scorpius, not Scorpio. Astrology – which is not a science – refers to the constellation as Scorpio.)

Scorpius’ bright stars are one of the few constellations that looks exactly what it is… a giant scorpion!

Depending on the month and the time of night, turn the star chart so that its stars match the orientation of Scorpius’ stars in the sky.

Where are the scorpion’s pincers?

When you look at the star chart, you’ll notice that an important part of the scorpion’s anatomy is missing! As we all know, scorpions have two large pincers in front, but Scorpius’ starry pincers (the ancients called them claws) were cut off by the Romans during the reign of Julius Caesar, and turned into into the symbol of justice, which we know as the constellation of Libra the scales.

In the image (left) the claws of Scorpius can be seen extending into Libra as depicted on Gerard Mercator’s 1551 celestial globe. But they have long been dropped and the scales are just that… a pair of scales.

However, the two stars representing the scorpion’s claws still bear their original Arabic names – Zubeneschamali and Zubenelgenubi, meaning respectively, “Northern Claw” and “Southern Claw.”

Be sure to take a look at Zubenelgenubi in your binoculars as it is an utterly gorgeous double star (two stars that are gravitationally bound and orbit each other).

Spectacular Antares

An incredible image of the surface of Antares taken by the European Southern Observatory. Image credit ESO

Antares is the brightest and most spectacular star in the constellation. The massive ruby red star is the heart of the celestial scorpion and its name, derived from the Greek term meaning “rival of Mars,” reflects its striking red colour, the same as that of the famed red planet. It is a red supergiant star, with a diameter of 946 million killometres. If Antares it took the place of our Sun, its surface would extend well past the orbit of Mars and into the asteroid belt. The enormous star is nearing the end of its life and when it does, it’ll blow itself to smithereeens in a supernova explosion. It lies 550 light-years away from Earth, so it could have gone supernova yesterday afternoon but we won’t see the fireworks for another 550 years when the light reaches us.

Look at Antares through binoculars, then move quickly past Sigma to Dschubba, a blue-white giant. The colour difference is dramatic! And afterwards lie back and casually scan the Scorpion’s crooked body from head to toe – along the way you’ll see some fabulous stars and clusters…

M4 Globular Cluster

M4 is a globular cluster and it lies right next door to Antares. Globular clusters are clusters of tens of thousands to millions of stars, bound together by gravity. Their stars are 11 to 13 billion years old. This places them close to the age of the universe itself, which is estimated to be around 13.8 billion years old. M4 is approximately 12.2 billion years old, and it lies 7,200 light-years away.

It is very easy to locate M4, as it lies only one degree west of Antares (that’s the width of your baby finger held at arm’s length). Scan in a circle with Antares always in your circular field of view. You will soon see M4 as a dim, fuzzy, round glow that resembles a distant ball of cotton wool. When you look at this ancient ball of stars, consider this: the stars within that fuzzy glow were already 7 billions years old when our Sun was born 5 billion years ago.

M7 Ptolemy’s Cluster

This cluster is visible to the naked eye as a fuzzy patch of bright starlight against the glow of the background Milky Way. It lies close to the scorpions stinger, just east of the star Shaula (“stinger in Arabic), and to the medieval Arabs it was known as the Scorpion’s venom.

We know it as Ptolemy’s Cluster after the astronomer Claudius Ptolemy who first recorded it in AD 130. as it was is one of the brightest, most beautiful open clusters in the sky. About 80 stars call this cluster home, and it was formed from a giant cloud of gas and dust about 200 million years ago. It lies 980 light-years from earth.

It is one of the one of the brightest, most beautiful open clusters in the sky and is absolutely stunning in binoculars. Several stars show subtle hues of yellow and blue, with a beautiful bright orange star lying close to the group’s center.

M6 Butterfly Cluster

Visible naked eye as a pretty bright smudge of starlight close M7, this cluster is known as the Butterfly Cluster because it bears a resemblance to the shape of a butterfly in binoculars or a telescope. It was formed from a giant cloud of gas and dust between 50 and 100 million years ago, and lies 1,500 light-years from Earth.

While not as dramatic as M7 in binoculars, M6 is a gorgeous collection of stars, most of which are hot, young, blue stars, but the brightest star is a superb orange giant. Can you see the beautiful butterfly shape?

Zeta – NGC 6231 – Cr 316

The area at the top of Scorpius’ tail is absolutely stunning in a pair of binoculars. The star Zeta is a striking double star through binoculars, with the brightest of the pair (Zeta-1) displaying an obvious orange tint, while its companion (Zeta-2) is blue-white. In reality, however, they are not related to each other. Zeta-2 lies 200 light years away, while Zeta-1 is an incredible 6,000 light years away! A third, unrelated star just to the south creates a striking equilateral triangle with the two Zetas.

The cluster NGC 6231 lies an astonishing 5,500 light-years away, yet its stars still shine brightly in a pair of binoculars, appearing as a small, bright gathering of stars. If you continue further north, the cluster Collinder 316’s stars are loosely scattered across 2 degrees and you ought to be able to see some three dozen of its stars ranging from bright to fairly faint. Taken all together, the two clusters and the Zeta stars form a wonderful asterism (star picture) that to me look remarkably like a celestial gecko! It truly is a gorgeous sight in binoculars!