Polaris, also known as the North Star, is a beacon for navigation in the Northern Hemisphere night sky. Its unique status comes from its alignment with the Earth’s axis of rotation, making it appear nearly stationary while other stars seem to circle around it. This constancy has made it a dependable guide for centuries. Unlike the brightest stars, Polaris is only moderately bright, typically a second-magnitude star, which means it requires a specific technique to locate it confidently.
Locating the Big Dipper
The first step in finding Polaris is to locate the Big Dipper, an asterism that is part of the larger constellation Ursa Major. This star pattern is one of the most recognizable in the northern sky, forming the shape of a large ladle. It is easily identifiable by its seven bright stars: four forming the bowl and three forming the handle.
In the Northern Hemisphere, the Big Dipper is circumpolar, meaning it never sets below the horizon for many mid-to-high latitudes. While its orientation changes depending on the season and time of night, its position is always visible in the northern sky.
Using the Pointer Stars to Find Polaris
Once the Big Dipper is located, identify the two stars that form the outer edge of its bowl, known as the “Pointer Stars.” These stars, Merak and Dubhe, are situated on the side of the bowl farthest from the handle. They act as a celestial arrow pointing directly toward Polaris.
To use them, mentally draw a straight, imaginary line starting from Merak, through Dubhe, and continuing outward into space. Polaris will be the first relatively bright star encountered along this path. The distance from Dubhe to Polaris is approximately five times the distance separating the two pointer stars, providing a clear reference for how far to extend the line. This relationship holds true regardless of the Big Dipper’s rotation or position, making it a highly reliable navigation method.
Confirming the North Star’s Identity
After locating the star using the pointers, there are two ways to verify that it is indeed Polaris. First, Polaris is the final star in the handle of a fainter constellation known as the Little Dipper, or Ursa Minor. While the rest of the Little Dipper’s stars can be challenging to see in light-polluted areas, finding Polaris confirms its position as the handle’s tip.
The second characteristic is its apparent stillness in the night sky. Because Polaris sits almost directly over the Earth’s North Pole, it appears nearly motionless while the rest of the northern stars trace large, circular paths around it. Observing this lack of movement confirms the star’s identity as the true North Star, which consistently marks the direction of true north.