There is a scene in the film “A Beautiful Mind” (2001) that says it all about constellations. Mathematician John Nash is standing with physicist Alicia Larde, looking at the stars. He asks her to name an object, an animal, anything. “An umbrella,” she says, and he finds one for her among the stars. “Do it again,” she beams, “an octopus,” and Nash points one out with her outstretched arm. Romance sizzles between them, but so does the excitement of finding patterns, of making sense of seeming randomness, of creating images out of a jumble of stars.
Today, fellow sky walkers, we visit one such jumble, a constellation that dominates the southern horizon in summer. To astronomical history, this constellation is the scorpion, Scorpio. Taking the same license as no less a mind than Nobel laureate Nash, however, I picture these stars as a mermaid. Mermaid or scorpion, let us find our constellation in the night sky.
Scorpio, to stick to its common Western name, is perched in the southern skies throughout summer, where it currently finds Jupiter and Saturn as nearby neighbors. The sky chart shows our scorpion in early July around 10 p.m. At that time, Scorpio looks nearly upright, just barely clearing the tree tops due south. As the night progresses, however, Scorpio slouches over toward the horizon, where it is harder to see. Later in the summer, Scorpio starts the night on a slouch, so the time to explore this constellation is right now.
Where to find Scorpio in the southern sky. (Illustrations by Marc Vilain) CLICK IMAGE TO ENLARGE.
Scorpio has a number of features visible to the naked eye. Right in the center of the scorpion’s body is a bright red star, Antares. The name usually translates from the Greek as “rival of Mars,” but a more useful translation might be “looks like Mars, but nope, not Mars.” On the far end of the scorpion’s body, at the end of the tail, are a pair of stars meant as part of the stinger, but also and more poetically known as the Cat’s Eyes. These are very evident with binoculars.
If you have access to a telescope, such as the library’s StarBlast lend-a-scope, Scorpio has four excellent telescope-only sights. These start with two globular clusters near Antares. The larger one, M4, is typical of globular clusters: In dark skies it appears as a ball of stars. Nearby is M80, a star ball so compact that it mostly appears as if someone had smudged the sky with the tip of a starry paint brush. In addition, down near the Cat’s Eyes are two open clusters, M7 and M6. M7 is larger and fills the eyepiece to overflowing with 60–70 bright stars. The M6 cluster is more compact but counts almost as many stars. Some see M6 as butterfly-shaped.
Each of these star clusters is interesting in its own right, but the fact that they all occur within one constellation makes them worth the telescopic trip (see star-hopping instructions below).
Scorpio is one of the oldest named constellations, known to Sumerians and recorded on Babylonian tablets from 1200 B.C. These constellations stood the test of time, and Scorpio in particular was later noted by the Greek astronomer Ptolemy in his catalogue of the heavens.
In Greek mythology, the stellar scorpion is associated with Orion, the hunter. As the myth goes, Orion had boasted to Artemis that he could kill any beast with his mighty club. Though Artemis was the goddess of the hunt, Orion’s boast did not sit well with her, so she sent Scorpio to do battle with Orion. The scorpion won, killing Orion with a particularly nasty sting. (Outside of myth, few scorpions are actually deadly.)
As so often happens in Greek mythology, Zeus cleaned up the earthly messiness by elevating both Orion and Scorpio into the stellar canopy. In our latitudes as well as those of the Greeks, Orion stalks the winter skies, but he is understandably chased down below the horizon by the summertime arrival of Scorpio.
Not all cultures see these stars as a creepy crawly. In traditional Hawaiian astronomy, the J shape of the scorpion’s body is a fishhook, and not just any fishhook. Demigod Maui was out fishing one day with his brothers, when he cast a magic hook into the sea. Up came some rocks. As his brothers rowed on, Maui kept pulling and the rocks kept coming, until they formed the islands now known as Hawaii.
With this maritime myth, we come back full circle to my view of this constellation. I like to picture these stars as a mermaid. She is floating on the surface with her arms folded behind her head, and with her fish tail curved around her in the water. Around her neck is a pendant with a colorful shell, Antares. If I had my way with the astronomical catalogue, this would be constellation Sirena, the mermaid, and Antares would be Cochlea, the shell.
Fellow sky walkers, whether Sirena or Scorpio, I urge you to spend some time in the coming weeks becoming familiar with this constellation. While you’re there, make sure also to view Jupiter and Saturn, which are both excellent telescopic sights right now. And especially do not resist the urge to map and name your own constellations among these summer stars. Warm summer nights are made for this.
Marc Vilain sees mermaids in the night sky from the roads and fields of Harvard.
to M6, M7, M4, and M80
If you have a gunsight finder, as with the library’s StarBlast: Rack the zoom all the way out; point the scope as close as you can according to the charts; look for fuzzy patches in the eyepiece; and then zoom in.
For scopes with a telescopic finder, typically a 10x50 mini-scope, try star hopping.
To find M7, first center the Cat’s Eyes in the finder scope. Move the scope leftward until the Cat’s Eyes are at the edge of the frame; most finder scopes reverse left/right and up/down, so the Eyes will paradoxically move to the left. On the opposite edge will be an orange star, G Scorpii. Center G (nudging left), then lift the scope about half a field of view plus a slight nudge to the left: M7 will come into view, rising from below.
To find M6: starting from M7, raise the telescope by a bit more than one finder field of view while nudging to the right. M6 will appear, again with left/right and up/down reversed.
To find M4, center the finder scope between Antares and Al Niyat, the next star towards the scorpion’s head. Then lower the scope a smidge so that the finder crosshairs form a flat triangle with Antares and Al Niyat. M4 will appear like a gauzy stretch of stars; linger on M4 and its ball-like shape becomes apparent.
To find M80, center the finder on Al Niyat. Nudge the scope up by a 1/4 finder view width to center on omicron Scorpii (“o” in the chart). The other bright star you see is rho Ophiuchi. Now imagine a triangle formed by omicron, rho, and a missing star (see chart). Center on where the missing star should be; M80 will appear in the eyepiece.
Use these charts and the star-hopping instructions to locate M7 and M6 (left-hand chart), and M4 and M80 (right-hand chart). Note that these charts are not drawn to the same scale. Note also that the nearly identically named Al Niyat and Alniyat are different stars. CLICK IMAGE TO ENLARGE