Thanks to a constellation of satellites, your smartphone can tell you exactly where you are — your precise latitude and longitude. It can even tell you which direction you’re facing. And it can do so even in the dark.

In centuries past, though, people had to rely on other sky objects to help them get their nighttime bearings: the stars. And if you’d like to see how it worked, we can help.

As night falls this evening, find the most famous of all star patterns: the Big Dipper. It’s low in the northwest, with the bowl hanging below the handle.

Next, draw a line connecting the stars at the outer edge of the bowl, Merak and Dubhe. Then extend the line to the upper right. Keep going until you reach the first moderately bright star. That’s Polaris, the North Star. Earth’s axis points toward the star, so when you face it, you’re looking due north.

The next step is to hold your fist at arm’s length, and see how many fists you can stack between Polaris and the horizon — the true horizon, not the tops of trees or buildings. Your fist spans about 10 degrees, so if there are three fists between Polaris and the horizon, the star is 30 degrees up. And that reveals your latitude: However far Polaris appears above the horizon corresponds to your latitude north of the equator.

Unfortunately, we can’t help much with longitude. That’s a much more difficult calculation to make — perhaps best accomplished with modern technology.
 

Script by Damond Benningfield

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