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Just click here or on the image below to open the printable map—then bring outside!

The Big Dipper and Pointers in the Sky

Getting your bearings under the night sky can be a challenge. It’s easiest to begin an evening of stargazing by first finding a single familiar star pattern (asterism) and using it to point the way. On March evenings, there is no better place to start than with the Big Dipper.

The Big Dipper asterism is composed of the seven brightest stars in the constellation Ursa Major, the Greater Bear. The shape of the Big Dipper never varies, but its orientation changes constantly.

This month’s Sky Map shows the Dipper as it appears during March in the late evening, when it seems to be standing upright, precariously balanced on its handle. Come back just a few hours later, and the Dipper will have moved so that it is upside-down as if pouring out its contents. Return at a different time of year, and the Big Dipper might be to the left of Polaris instead of on the right as it is in March. Learn to recognize the Big Dipper no matter what its orientation is.

The Dipper’s stars always point the way to other celestial sights. The two stars that form the front end of the Dipper’s bowl are known as the Pointers. They point directly toward Polaris, the North Star, in Ursa Minor, the Lesser Bear. Because Polaris points the way to true north, it has long been a vital guidepost for navigation on both land and sea. When you use the Pointers to find Polaris, you’ll be doing the same thing as countless explorers and sailors have done in the past.

The stars of the Big Dipper’s handle form a graceful curve or arc. If you extend this curve past the end of the handle and follow it two more “handle lengths,” you’ll end up at the bright star Arcturus in Boötes, the Herdsman. The main stars of Boötes form a somewhat lopsided kite shape. 

Once you’ve reached Arcturus, straighten out the curve and make a beeline for Spica, the brightest star in Virgo, the Virgin. The journey from the Big Dipper to Spica has given rise to a popular astronomer’s refrain: “Arc to Arcturus, then drive a spike to Spica.” Once your gaze has wandered from the Big Dipper to Arcturus to Spica, perhaps you’ll remember the refrain the next time you spot the Dipper.

Using the Big Dipper to orient yourself helps to overcome a problem that’s common to all star gazers: grasping the scale of the sky. Translating what’s shown on a sky map to what you see in the sky can be difficult. Distances in the sky seem greater than what they appear to be on a map. Starting with a bright asterism such as the Big Dipper and then extending your view to encompass Arcturus and Spica can help you to relate your map to the sky that it represents.

Once you understand the scale of the sky, it becomes much easier to find other stars and constellations. On our March map, look for points of interest such as the sinuous body and distinctive head of Draco, the Dragon; the beautiful Tiara shape of Corona Borealis, the Northern Crown; and the Keystone asterism at the heart of Hercules, the Roman Hero.

Enjoy the March night sky!

March Sky Map

Click here or on map below to enlarge (PDF).

Note: How to Read the Sky Map

Our monthly sky map does not show the entire sky, which would be almost impossible. Instead, the map focuses on a particular region of the sky each month where something interesting is happening. The legend on the map always tells you which direction you should facing, based on midnight viewing. For example, if the map legend says “Looking Southeast,” you should face southeast when using the map.

The map is accurate for any location at a so-called “mid-northern” latitude. That includes anywhere in the 48 U.S. states, southern Canada, central and southern Europe, central Asia, and Japan. If you are located substantially north of these areas, objects on our map will appear lower in your sky, and some objects near the horizon will not be visible at all. If you are substantially south of these areas, everything on our map will appear higher in your sky.

The items labeled in green on the sky map are known as asterisms. These are distinctive star patterns that lie within constellations. When getting your bearings under the stars, it’s often easiest to spot an asterism and use it as a guide to finding the parent constellation.

The numbers along the white “Your Horizon” curve at the bottom of the map are compass points, shown on degrees. As you turn your head from side to side, you will be looking in the compass direction indicated by those numbers. The horizon line is curved in order to preserve the geometry of objects in the sky. If we made the horizon line straight, the geometry of objects in the sky would be distorted.