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An ode to the Summer Triangle
Scott Levine has a soft spot for the superstar asterism of the warmer months
On a breezy night when I was still new to my neighbourhood, I slipped out into the dark, stumbled to my favourite northfacing spot and looked up. My hopes for quiet were dashed when my chatty neighbour joined me, but as early-season crickets chirped, we shifted our gaze between branches, stared into one of my favourite patches of the sky and talked about the stars, and about nothing.
Growing up in a dense suburb, not far from a rail station and small airport, the Summer Triangle asterism was one of the few groups of stars that pierced the sky-glow enough that I could see it easily. Its corner stars are among the night’s brightest, but the shape they sketch is compact and sleek, like a sensible sedan car. I’ve loved it ever since. Blue-white Vega (Alpha (α) Lyrae) arrives just above the northeast horizon in mid-May, with Deneb (Alpha (α) Cygni) and Altair (Alpha (α) Aquilae) close behind.
As the weeks passed, I ran into that same neighbour from time to time. Stars rise four minutes earlier each night, which doesn’t seem like much, but little by little these minutes add up. By August, as we talked about racing from work to soccer games, then home to get dinner on and off the table, the Triangle rose up to where it might be easier – and safer – to lie on our backs in the street than to twist our necks to find it. It would be January before the minutes carried those stars out through the western dusk.
Altair and Vega are just across town as things go: only about 16 and 25 lightyears away, which helps them appear unusually bright in our sky. Deneb, though, is more challenging. It’s one of the most distant star systems we can see with our unaided eye: over 2,000 lightyears away. So it’s not near the others at all, but far behind them. The Deneb we see is much more subdued than Altair and Vega. If we’re able to see it so brightly from so far away, imagine what it would be like if it were much closer.
Let’s consider the other stars within and near the Triangle: the unlabelled, understated, anonymous stars. Other than Vega, all of the constellation Lyra’s stars are dim, as are those in Vulpecula (the Fox), Sagitta (the Arrow), Delphinus (the Dolphin) and Equuleus (the little horse), the group of small constellations that carve a path through the Triangle.
These stars are all listed and catalogued, but many aren’t named. I love to look up and think about what’s out there – not just what we know, but also what we don’t – and imagine what we’ll learn one day.
In dark-sky places, far behind Deneb, we can even see the soft glow of countless stars running through the Triangle, their light blurred together by many thousands of empty lightyears: the band of our Milky Way Galaxy.
As those early few weeks turned into years, and toddlers turned into teenagers, those moments with neighbours were some of my favourite times. My friend has since moved away, but you never know who you might run into tonight when out under the night sky. I hope you’ll look up… and try not to hurt your neck.
Scott Levine is a naked-eye stargazer and an astronomy writer based in New York’s Hudson Valley