Orion’s hunting dogs roam the sky


By Tom Burns - Stargazing



Orion has a reputation for being a winter constellation, but its visibility stretches well into spring. Right now, he is ideally placed in the southern sky just after dark. The length of his sojourn in the sky makes it possible to find some of the constellations that make up what is sometimes called the Orion Tableau.

Let’s start with his two loyal hunting dogs following him across the sky.

That’s right. Dogs. Plural. Any self-respecting hunter has at least two huntin’ dawgs. As I hiked the trails of West Virginia, I saw bear hunters preceded by entire packs of fearsome pooches. Orion, a manly man of great manliness, is no exception.

Canis Major (the “Greater Dog”) stands below and to the left of his master, who dominates the early evening sky this time of year. You can’t miss old Major. Use the three bright stars in Orion’s belt as pointers to find the brightest star in the nighttime sky, Sirius, the Dog Star, representing the faithful pup’s head.

Like most diehard hunters, Orion has an emergency backup dog, Canis Minor (the “Lesser Dog”), far to his upper left and far harder to find than other constellations in the group. Use the stars of Orion’s shoulder, Betelgeuse and Bellatrix, as pointer stars.

Minor’s only bright star is Procyon, which means “before the dog” in Greek. The name indicates that, like most small dogs of my acquaintance, Minor is a touch hyperactive. It scoots ahead of Major, rising above the horizon just before the Greater Dog.

Wedged to the right of Canis and below Orion is Lepus, the Hare. Major is presumably drawing a bead on the hare as the fearful bunny cowers at the feet of the mighty Hunter.

To Orion’s right is another, far-more-formidable example of the Hunter’s prey. Look for the V-shaped head of Taurus, the Bull, setting in the west. It’s hard to miss Taurus because of his bright bloodshot eye, the orange-red star Aldebaran.

No mythological story that I know of explains how Orion got his dogs. The ancient myths associate them with different owners.

Canis Major is sometimes called Laelaps, a dog so fleet of foot that no prey could escape it. In one story, the dog and a javelin were presented to Procris, daughter of the king of Athens and wife of the hunter Cephalus.

The javelin was magical. Its bearer could never miss, which turned out to be bad luck for Procris. She and her husband were hunting one day when Cephalus accidentally ran her through.

Thus, Cephalus inherited the dog. They went to a small Grecian town called Thebes, where a nasty fox raided the local hen houses.

Cephalus decided to do his good deed for the decade. He set the dog loose to catch the fox. There was one small problem — the fox was so fast that nothing could catch it.

Here we have one of those logical conundrums that the Greeks were so fond of ­— a dog that could catch any animal and an animal that could never be caught.

Somebody had to do something, or the ancient logic textbooks would have to be rewritten. So Zeus, the head honcho on Mount Olympus, turned the fox and dog into stone. The dog he placed in the night sky to honor his swiftness. The fox became a lawn decoration, I guess, because no such ancient constellation exists.

The Lesser Dog represents Maera, one of Icarus’s canine companions. Icarus was the first human to learn to make wine. He got some shepherds drunk, and in gratitude, they killed him on the spot. (If you must drink, please don’t drink and herd sheep.)

In Lassie-like fashion, Maera ran to get help. He dragged Icarus’s daughter Erigone to the scene, where, grief-stricken, they both committed suicide.

Just how a dog can take its own life is lost in the inky depths of history. In any case, the gods put the Lesser Dog in the sky to honor its loyalty. We see it to this day, its head up, howling with pain at the loss of its master.

Ah, another inspiring tale of yore. It takes all kinds to make a universe, I suppose.

Canis Minor is nothing much to look at and contains practically nothing for a stargazer to see besides, perhaps, Procyon, its brightest star. However, Canis Major is awash with some of the most spectacular sights in the starry sky.

The best thing about the late winter, astronomically speaking, is the winter Milky Way. This silvery streak represents billions of stars in our galaxy that are too far away to resolve with the unaided eye.

One of the best places to scan is in the direction of Canis Major if you don’t mind breaking out your binoculars.

Start by finding Sirius, the Dog Star, and observe it scintillating and perhaps changing colors as it twinkles like a mad dog. The effect is even more pronounced in binoculars.

The Canis-Major region is particularly rich in open clusters — densely packed collections of stars. Open clusters are born out of enormous clouds of hydrogen gas.

Eventually, most of the stars in a given cluster will drift apart. The fact that they are still close suggests they are recently born. They measure their lives so far in millions, not billions, of years.

The most straightforward cluster to find is M41. Look below Sirius with binoculars for a lumpy patch of light. A small telescope will reveal a loose collection of about three dozen stars.

The stars in M41 are about 190 million years old. Stars like our sun last about 10 billion years, so these stars are celestial babies.

The cluster is relatively distant at about 2,300 light-years away. (A light-year is about 6 trillion miles.)

It contains about 100 stars sprinkled across a space about 25 light-years wide. Despite its distance, in binoculars, it appears huge. Expect a glowing light patch about the size of the full moon.

Above and slightly to the left of Sirius is M50. From dark, rural skies, you might just be able to see it in binoculars as a hazy ball of light.

In a small telescope, you’ll see about a dozen of the 600 or so stars in M50. Look especially for a pretty, reddish star at the southern tip of the cluster. Most of the other stars in M50 have a bluish tint, indicating that this cluster is a relatively young one at about 140 million years old.

We see fewer stars in M50 partly because it is farther away than M41. At almost 3,000 light-years distant, the stars of M50 are also packed into a much smaller space nine light-years wide.

Viewing the cluster NGC 2362 requires a telescope. Point it at the faint star Tau near Canis Major. Surrounding Tau is a beautiful sprinkling of faint stars. NGC 2362 is about 5,000 light-years distant. At only five million years old, it is among the youngest star clusters we can see.

To the left of NGC 2362, the cluster M93 will just be visible as a faint fuzzball in binoculars. You will see a band of about 20 reasonably bright, densely packed stars in a small scope.

M93 is a cluster of 250 or so stars strewn across a 20-light-year section of sky. You’ll only see a handful of them in a telescope, but the view is still glorious. According to Walter Scott Houston, perhaps the most skilled amateur telescopist of his generation, many observers say the cluster resembles a starfish.

It lies about 3,500 light-years distant from Earth. At an estimated 387 million years old, it is among the oldest of the bright clusters in the direction of Canis Major.

I’ve saved the best for last. Two open clusters, M46 and M47, are to the left of Canis Major’s head and fit nicely into the field of wide-angle binoculars.

M46 appears as a small cloudy patch. M47 is wider and brighter. However, appearances can be deceiving.

In a small scope, M47 resolves into a few conspicuous stars. M46 looks like dozens of speckles of light with hundreds of other stars just visible.

The effect is spectacular. The M46’s unresolved stars weave a glow among the visible stars.

At 1,624 light-years away, M47 is three times closer than M46, but M46 has five times more stars. M47’s 50 stars seem more spread out because of their proximity to us.

There you go. You perhaps went outside dreading the chill. You’ll go back to the warmth of your home with stars in your eyes.

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By Tom Burns

Stargazing

Tom Burns is the former director of the Perkins Observatory in Delaware.

Tom Burns is the former director of the Perkins Observatory in Delaware.