Fishing the Fall Sky

The perfect cast, the cutthroat rises to the hand-tied fly, and the battle royal ensues. Such is the drama of fish versus fisher, playing out on countless mountain streams in Big Sky Country through the long, lazy summer and the earliest chills of autumn. But when the leaves fall and frost rimes the grass with a vengeance, it’s time to pack away the rod and reel and turn our aquatic attentions to the sky. For the fall heavens are decidedly watery and filled with exotic catches enough to fill any astronomical creel.

The damp sky denizens of autumn are challenging to spot, so start with something easy—like the Great Square of Pegasus, the flying horse. The square lies high southward by 11:00 pm in early October and by 8:00 pm in early November when Daylight Saving Time is over. Since the square outlines the front half of the horse rising from the ocean, we can immediately locate the part of the sky referred to as “the sea” stretching south of the square to the horizon. Got your line ready?

Immediately below the Great Square in a dark sky, find a faint “Circlet” of stars that marks the western fish of the constellation Pisces. Obviously, it’s already somebody’s catch, for a sharp eye can trace a line of faint stars marking the cord attached to the fish’s tail, tied neatly in a knot and then stretching up alongside the left-hand side of the square to the tail of the faint eastern fish. Now trace a line horizonward from the right-hand side of the square, and glinting just above the ridgeline you’ll spy the bright star Fomalhaut marking the mouth of another fish made up of an elongated curve of modest stars. This is Piscis Austrinus, the Southern Fish and in some traditions the parent of the Pisces pair.

Now go back to Pisces and cast your line of sight a little west of the Circlet to a small four-star figure—one star in the middle surrounded by three others. This is the center of Aquarius, the waterbearer, a gangly pattern depicting a clumsy fellow adding to the general humidity by dumping a jar of water into this watery section of the sky. Hunt a little farther down and right of Aquarius to spy the distinctive boat-shape of Capricornus, the seagoat, half fish and half bearded bleater.

If you’re still under your catch limit, go back to the Great Square and trace down the left-hand side until you reach a star that marks the tip of a slightly flattened ice cream cone of stars that makes the body of Cetus the whale. A pentagon shape up and left of the cone makes the flukes to complete the sea mammal. Or turn this bad boy of the sky into a true sea monster by turning the flukes pattern into a nasty head with a thin star neck connecting it to the body. That will give you the monster who threatened Andromeda (a horn-shape of stars firmly tethered to the Great Square’s upper left star) with death-by-devouring until Perseus turned the tables and calcified Cetus by giving him a peep of the head of the Gorgon, Medusa—a grisly chachki he just happened to be carrying in his satchel at the time.

Another fabled monster figures indirectly in the fall sky: Typhon, a terrifying multi-headed, fire-breathing creature so dreadful that upon its approach, the goat-footed god Pan fled into a river, turning himself into the mer-goat Capricornus to escape. Likewise, Aphrodite and her son Eros (a.k.a., the Roman Venus and Cupid) transformed themselves into fish and plunged into the River Euphrates at Typhon’s entrance, tying themselves together with a cord so as not to lose each other in the currents. We see them represented in this guise as the constellation Pisces. Perhaps Typhon even caused Aquarius, also known as Ganymede, the youthful cupbearer of the gods, to spill his large drink.

Regardless, there’s another prize catch in the watery sky this fall: the Red Planet Mars, at opposition on November 7 as the speedier Earth passes it in its orbit and it lies relatively close and bright in space. It’s unmistakable above the head of Cetus, blazing like a baleful red eye.

They all make for a colorful cast of characters, so plunge in and see what you can snare—in the moments between fly-tying and dreaming of that other cast, over sun-sparkled summer waters when the trout are hungry again.

Jim Manning is head of the Office of Public Outreach at the Space Telescope Science Institute in Baltimore, MD, but maintains roots just "Outside Bozeman."