Marcia and I have a hot tub in our backyard, and we end most days (weather permitting) by sitting out in it together. On clear nights, we always make a point of noting and admiring the objects in the sky above us, both the ephemeral, atmospheric ones that cross our field of vision quickly (fireflies, airplanes, satellites, the International Space Station, shooting stars) and the abiding, celestial ones, whose motion is apparent only through sitting outside, night after night, on a year-round basis.
Our enjoyment of this evening ritual is always enhanced by knowing what we’re seeing. And different seasons have different looks. Right now, we’re observing the Summer Triangle of stars (Deneb, Vega and Altair) disappearing below our tree-line to the west, while Jupiter is bright to the south of us, the constellations Pegasus (a big square) and Cassiopeia (a big “W”) dominate the view directly over our heads, and Perseus and the Pleiades creep up from the east. (Our house blocks most of our eastward view, so we don’t see things until they’re about 75 degrees above the horizon in that direction).
We’ve got a fair amount of light pollution in our neighborhood, so we don’t see a ton of celestial detail. The dusty heart of the Milky Way (our home galaxy) is only faintly visible to us on rare, moonlight free, cold, crisp evenings, for instance, and we can only clearly see the Pleiades’ constituent stars if we take the binoculars out with us. But the brighter objects in the sky certainly give us plenty to admire, point out and discuss, much as human beings have done throughout recorded and pre-historic times. I can think of few things, in fact, that bind us as tightly to our forebears as looking up in wonder at the sky.
Unfortunately, I think this is a dying habit in our culture. When I’m outside at night with other people, I will often point out and name some fairly obvious object in the sky, and 99% of the time, their reaction will be something along the lines of “Really? I didn’t know that. How do you know that? And what’s that over there? Huh!”
It’s a great conversation starter, and if I were a younger, single dude, I would probably still be using this knowledge for evil, not good. “Come . . . let us step away from the light of the camp-fire, you and I, the better to admire the wonder that is Arcturus.” This is powerful, primal wisdom. Strong Juju.
So it occurs to me that I should impart such wisdom upon the young folk who might use it more fully today. Toward that end, I offer, below, an even dozen of the easiest-to-find, easiest-to-remember objects in the sky. Pretty much any time throughout the year, you should be able to spot at least a few of them, point, and bedazzle the object of your desire.
Note: I’m operating under the assumption that you already know what the Sun and the Moon look like, so I’m not including those objects on the list below. Also, note that this guide only applies to those with a view of the Northern Sky, so the tips offered here will generally work in most of the continental United States, at least, plus locations of similar Northerly latitudes elsewhere. If you live in New Zealand or Argentina, though, you’re going to need to find another mentor to help you with The Southern Cross, Alpha Centauri and the like.
The Big Four Planets:
Not “Big Four” in terms of their size, necessarily, but in terms of their brightness in the night sky. (Neptune and Uranus are much larger than Mars and Venus, but they’re also much, much further away, and you won’t be pointing them out to anybody). At their fullest magnitude, Venus, Jupiter and Mars are brighter than any of the stars in the night sky, and Saturn is brighter than all but a couple of them.
The planets move on a night-to-night basis faster through the sky than the stars behind them do. (The word “planet” is derived from the Greek word for “wanderer,” in fact). So how do you keep straight which planet is where? I recommend using Sky and Telescope‘s Interactive Star Chart, which can be found here. Put in your location and time and, hey presto, you get a sky map that shows you what’s what and where. (Keep in mind when you look at a sky map that east is to the left, and west is to the right, the opposite of traditional maps, because you are looking up at the sky, not down at the ground).
As I write, Jupiter is stunning in the Southern sky in the 10 PM to midnight slot, when we’re usually outside. If you go out yourself, turn and look South, and that big bright object half-way between the horizon and the local zenith (the spot directly above your head) is Jupiter. If you have a good set of high-powered binoculars and steady hands, you can even see up to four of its moons. Wow!
It’ll be awhile before the other Big Four planets are visible from here at that time of night (though Saturn and then Venus will be rising in the morning to the east soon), but if you just consult the link above periodically, you’ll easily be able to keep track of which wanderer is where. They’re hard to miss.
The Big Three Constellations:
6. Ursa Major (The Big Dipper)
7. The Summer Triangle (not a constellation in the classical sense, though it’s a very visible, findable, notable presence in our Northern sky)
These three groupings of stars are large, bright, and easily spotted, and at least one of them will be visible every night, throughout the year. In the 10 PM to midnight slot, when we normally stargaze, Orion will be most prominent from about now until March, Ursa Major from about January to September, and the Summer Triangle from about May to November. You can use the Sky and Telescope site above if it helps with first identification, but once you’ve seen each of these, they’re pretty easy to find again. It’s also great to know the name of at least one star in each constellation. That shows that you’ve got depth.
Orion (The Hunter) is most easily recognized by the distinctive straight line of three bright stars that make up his belt. Even in highly light-polluted skies, you should be able to see at least the belt, plus two stars in his shoulders, and two stars in his feet. The two brightest stars in the constellation are Betelgeuse (top left shoulder) and Rigel (bottom right foot). Orion moves East to West across the sky, when looking in a Southerly direction.
Ursa Major (The Great Bear) is usually called the Big Dipper, and that’s what it looks like. It’s much brighter than the Little Dipper, which rotates about Polaris, the North Star. (More on that later). The “knuckle” in the handle of the Big Dipper is called Mizar; it’s not the brightest star (that would be Alioth, one star up on the handle), but it’s the easiest to identify. Ursa Major moves East to West across the sky, when looking in a Northerly direction.
The Summer Triangle actually includes the brightest stars from three separate constellations: Vega (in the constellation Lyra), Deneb (in the constellation Cygnus), and Altair (in the constellation Aquila). In modern night skies, especially in urban or suburban areas, you don’t see much of Lyra and Aquila, hence the reorganization of their prime stars into the more easily spotted Summer Triangle. You can still see most of Cygnus (The Swan), though, and Deneb serves as its head, with its wings inside the Triangle. Altair is the star closest to the horizon, and Vega is the other corner. The Triangle moves East to West across the sky, when looking almost directly overhead.
One note on the images: keep in mind when you look for these constellations, they may not be oriented in the same way the photos are. Orion, for instance, at 10 PM right now looks like he’s laying flat on his face to the East, so the belt doesn’t run side to side from our perspective right now, it runs up and down.
Four Other Important Star Combinations
8. Sirius and Aldebaran
9. Castor and Pollux
10. Arcturus and Spica
11. Polaris and Capella
Once you’ve learned Orion and Ursa Major, you can use them to help you find other prominent stars in the sky. It may actually help you to be looking at a star chart when you read these tips, to help visualize the relationships better.
Let’s go back to Orion’s belt. If you follow the line of his belt downward, toward the horizon, the next really bright star that you will see is Sirius, which happens to be the brightest star in the night sky, from our perspective. Now, go back to the belt and follow it upward, toward the zenith; the next really bright star that you will see is Aldebaran.
Now, let’s look at Orion from another dimension: draw a line between the two brightest stars (Rigel in his foot and Betelgeuse in his shoulder), and follow that line toward the zenith. You will see a bright pair of nearly identical stars along this line: Castor and Pollux, The Twins, in the constellation Gemini.
If Ursa Major is the dominant constellation in the sky, then you need to remember this phrase: “Arc to Arcturus, then onward to Spica.” If you follow the curve of the Big Dipper’s handle away from the skillet bottom part, and imagine that curve continuing across the sky, the next bright star you find will be Arcturus, the second brightest visible star this far north. Continue that arc further, and you will arrive at Spica. The distance from the last star of the Dipper’s handle to Spica is about half the distance between the horizon and the zenith.
Going back to the Big Dipper again, if you follow the line of the front face of the skillet (the two stars further away from the handle) toward the North (away from the skillet bottom), the next somewhat bright star you will find is Polaris, the North Star. It never moves, from our perspective. Everything in the night sky rotates around it. If things are relatively clear, you will be able to see that Polaris is at the end of the handle of Ursa Minor, the Little Dipper.
And, again, one more time back to the Big Dipper: follow the line of the bottom of the skillet, away from the handle, and the next bright star you find is Capella, another of the ten brightest stars visible in the Northern Hemisphere.
One Cluster of Stars and Dust:
12. The Pleiades
The Pleiades are a closely-packed cluster of stars and dust that look like a smudged spot in the sky when there’s light pollution about, though in clear, dark skies, you can optically resolve the brightest stars in the cluster. They’re often harder to spot in typical suburban or urban settings, but well worth finding. If you follow the line of Orion’s belt toward Aldebaran, per the tips in the section above, and keep going, you will come to The Pleiades. Since your peripheral vision is better than your direct vision, it’s sometimes easiest to spot them first out of the corner of your eye, rather than by direct sighting. It’s also great to look at The Pleiades through binoculars, so you can really see “The Seven Sisters” clearly. Trivia: In Japan, The Pleaides are known as Subaru, and the logo of the car company of that name is a stylized representation of this star cluster.
So there you go. With that small, rudimentary understanding of the lights in the sky above us, you should be able to make interesting conversation in any outdoors, late night setting, weather permitting. You’ll also come to appreciate the associations between what’s in the sky and what’s happening seasonally. I always get wistful when I see Orion in the sky for the first time each year, for example, since it means that we’re past harvest time, and winter will soon be upon us.
Be sure to make a point like that while pointing out Rigel and Betelgeuse to your new friend. Sensitivity supplements knowledge nicely.