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Previous:
What Is Stargazing?

Next:
When and Where to Stargaze

How to Get Oriented in the Night Sky

You don’t need to be on a remote mountaintop with a fancy telescope to enjoy stargazing. These five steps will help you get started anywhere with just your naked eye:

1. Know Where You Are

What you can see in the night sky depends on where you are on Earth. If you’re in Seattle, for example, you can see the Big Dipper circle slowly above you in the sky at any time of the night, at any time of the year. In Miami, however, the Big Dipper rises in the northeast and sets in the northwest during the summer, and can’t be seen at all in the winter. This is because latitude—how far north or south you are—affects what stars you see. (On the other hand, longitude—how far east or west you are—does not.) You can find your latitude on a map or look it up online.

It’s also important to know which way is north so you can get your bearings in the sky. If you’re not sure what direction you’re facing, look at a compass or remember that the Sun will have set in the west. With practice, you’ll be able to find north just by looking at the stars.

2. Look Up

When you go outside, always wait a minute for your eyes to adapt to the dark before you get started—this will help you see fainter stars. Look at the ground for a few minutes until you feel adjusted, and avoid looking at streetlights or headlights or using flashlights while you stargaze.

Zenith and nadir: In stargazing terms, the highest point in the sky directly above you is called the zenith, and the point directly below you (under your feet) is called the nadir. It’s important to note that, unless you’re standing at exactly the North or South Pole, the sky does not rotate precisely around the zenith.
Stars vs. planets: At first, the night sky may look vast and intimidating, with what seems like an infinite number of stars. The human eye, however, can see only about 6,000 stars, even in the best observing conditions. The first objects you’ll see are the brightest ones—and these are often planets, not stars. A good way to tell planets from stars is with the “twinkle test”: stars twinkle, whereas planets appear to shine steadily.

3. Find the North Star

The North Star, or Polaris, is a good first star to identify—it’s the only star that’s always in the same spot in the sky, no matter what time of night or time of year. There are two ways to find it:

The Hand Scale

The North Star is always straight above the north horizon, and its height in the sky is the same as your latitude. For example, in Phoenix (latitude 33°N), the North Star is 33° above the horizon looking due north.

If you hold your arm out straight, you can use your hand as an approximate scale to measure degrees in the sky: a clenched fist is 10°, and the width of an index finger is 1°. Start with the bottom of one fist lined up with the north horizon then stack your other fist on top, then move your bottom fist on top of that one, counting 10° with each fist. In Phoenix, for example, if you stack three fists and count 30°, then stack three index fingers to reach 33°, the North Star should be right above your top finger.

The Big Dipper and Little Dipper

The Big Dipper is one of the brightest and easiest asterisms, or clusters of stars, to spot in the night sky. (It’s not technically a constellation, as it makes up only part of the full constellation Ursa Major.)

Four stars make up the Big Dipper’s “bowl,” and another three make up its “handle.” The two stars at the end of the Big Dipper’s bowl are pointers—if you join these with an imaginary line and extend that line from the bottom of the bowl upward, you find the North Star. Or, if you can spot the less bright Little Dipper, which has the same shape as the Big Dipper but is upside-down, you can also find the North Star at the end of its handle.

4. Know How the Sky Moves

The motion of the night sky is caused by the Earth rotating west to east on its axis, an imaginary line between the north and south poles. The Sun, Moon, stars, and planets all seem to rise in the east and set in the west due to this rotation.

The Celestial Sphere

To help visualize these motions in the sky, stargazers imagine the Earth at the center of a giant spinning celestial sphere that’s covered with all the stars. If you extend the Earth’s axis from the north pole until it hits the celestial sphere, you find the north celestial pole. All stars rotate counterclockwise around this point, which, conveniently, is also the location of the North Star.

Only stars that lie on the celestial equator will rise/set exactly in the east/west. Stars that lie between the North Star and the horizon will stay above the horizon all night long.

Diurnal and Annual Motion

Because of the Earth’s rotation, all stars rotate around the north celestial pole once each day. This is called diurnal motion. The Earth also moves in its orbit around the Sun—finishing a complete cycle in one year—which causes the stars to rise and set an average of about four minutes earlier each night. Called annual motion, this adds up to about a half hour each week, or two hours each month. Annual motion is what allows us to see different stars at different times of the year. Note that planets, though, don’t follow the same motions of the celestial sphere. Instead, they follow a different path called the ecliptic (see The Planets).

5. Locate Prominent Constellations

Once you’ve found the North Star, find a prominent constellation to use as a landmark. You’ll then be ready to find more objects using a star chart (see Stargazing Tools) and move on to more advanced stargazing. Different prominent constellations are visible at different times of the year.

Prominent Summer Constellations/Asterisms

Summer Triangle: This large triangle is made of three of the brightest stars in the sky: Vega, in the constellation Lyra (the Lyre); Deneb, in the constellation Cygnus (the Swan); and Altair, in the constellation Aquila (the Eagle). To find the Summer Triangle, look high overhead on most summer nights. If it’s dark enough to see the bright belt of the Milky Way, that belt will cut straight through the Summer Triangle.

Prominent Autumn Constellations/Asterisms

Pegasus: This mythical winged horse includes four bright stars, the Great Square of Pegasus, that outlines its body. To find Pegasus, first find the star in the bowl of the Big Dipper that’s closest to the handle. Now draw an imaginary line from this star through Polaris, and you’ll hit a corner of the Great Square.
Cassiopeia: This mythical queen sitting on her throne is marked by a pattern of five bright stars that look like a big “W.” To find Cassiopeia, follow the first star in the handle of the Big Dipper through Polaris.

Prominent Winter Constellations/Asterisms

Orion: The mythical hunter, Orion, is outlined by a rectangle of bright stars with three bright stars in the middle representing his belt. Betelgeuse, the star at his left shoulder, has an orange-red color. Far to the lower left of his belt is Sirius, the brightest star in the sky. To find Orion, look south for three bright stars in a short, straight line—Orion’s belt. The two bright stars above the belt are Orion’s shoulders; the stars below the belt are his knees and feet.

Prominent Spring Constellations/Asterisms

Ursa Major (Big Dipper): “Ursa Major” is Latin for “big bear.” The Big Dipper comprises just part of the bear—the back of its body and its tail. To find Ursa Major, see “3. Find the North Star” earlier in this section.
Ursa Minor (Little Dipper): “Ursa Minor” is Latin for “little bear.” The Little Dipper and Ursa Minor are the same thing—the North Star is located at the end of the bear’s tail. To find Ursa Minor, see “3. Find the North Star,” earlier in this section.
Leo: Leo is a lion with his mane defined by bright stars that look like a backward question mark. Leo is directly below the bowl of the Big Dipper. To find Leo, draw an imaginary line south (away from the North Star) through the two stars that make the left edge of the bowl, and you’ll hit Regulus, a star on Leo’s chest.