Polaris, the North Star, is the most useful star in the sky for anyone in the Northern Hemisphere. It sits almost directly above Earth's north pole, less than a degree away from the true celestial pole, which means it barely moves while every other star appears to wheel around it through the night. Find Polaris and you have found north, and with north established, you can work out every other direction, estimate your latitude, and start learning the rest of the sky. Sailors, travellers and explorers have relied on it for thousands of years, and it is still the first star every beginner should learn.

Polaris is not especially bright. It is a moderately bright star, roughly the 50th brightest in the sky, and in a light-polluted city it can be hard to pick out among the brighter stars around it. That surprises many beginners, who expect the most famous star in the sky to blaze. Its fame comes not from brightness but from position. Everything else in the northern sky circles around it, and once you know how to find it, you will never lose it again.

The pointer stars: the fastest way to find it

The easiest route to Polaris runs through the Big Dipper, the most recognisable pattern in the northern sky. Find the Dipper's bowl, the four stars that form a rough saucepan shape, and look at the two stars on the outer edge of the bowl, farthest from the handle. These are Dubhe and Merak, known as the pointer stars. Draw an imaginary line from Merak through Dubhe and keep going in the same direction for about five times the distance between the two stars, and you will land almost exactly on Polaris.

If the Big Dipper is below the horizon or hidden behind trees, Cassiopeia offers a backup route. This constellation looks like a W or an M, depending on the season, and it sits on the opposite side of Polaris from the Big Dipper. The middle of the W points roughly toward Polaris. Between these two signposts, at least one is usually visible on a clear night in the Northern Hemisphere. A free star chart app can confirm your identification the first few times, but try to learn the star hops by eye so you can find Polaris without a screen.

What Polaris tells you about where you are

Polaris does more than point north. Its height above the horizon is, to a good approximation, equal to your latitude. Standing at the equator, Polaris sits on the horizon. From London, at about 51 degrees north, it stands about 51 degrees above the northern horizon. From a city in the southern United States, it hangs lower, and from anywhere south of the equator it is below the horizon and invisible. Medieval sailors used this relationship to judge how far north or south they had sailed, long before accurate clocks made longitude possible.

There is a catch worth knowing: Polaris has not always been the North Star, and it will not always be. Earth's axis wobbles slowly like a spinning top, tracing a circle in the sky over about 26,000 years, a motion called precession. Around 3,000 years ago the North Star was Thuban, in the constellation Draco, and in about 12,000 years it will be Vega, one of the brightest stars in the sky. Polaris happens to be close to the pole right now, which is a lucky coincidence of our era, and it will drift away over the coming centuries.

Navigating by the stars once you have north

With Polaris found and north established, the rest of the sky starts to make sense. Face Polaris and east is on your right, west on your left, south behind you. From there you can learn the seasonal constellations one at a time: Orion in winter, Leo in spring, the Summer Triangle in summer, and the Great Square of Pegasus in autumn. Each one becomes a signpost, and over a year you will build a mental map of the whole sky. That is how people navigated for millennia, and it still works perfectly well tonight.

Start with short sessions. Pick one new constellation per outing and learn it properly rather than trying to memorise the whole sky at once. A dim red torch, a printed star chart and a reclining chair will take you further than any expensive equipment at this stage. And remember that Polaris is only visible from the Northern Hemisphere: travellers heading south of the equator will need to learn the Southern Cross instead, which plays the same role in southern skies.

Frequently Asked Questions

Q: Is Polaris the brightest star in the sky?

A: No. Polaris is only moderately bright, roughly the 50th brightest star. Sirius is the brightest star in the night sky. Polaris is famous for its position, not its brightness.

Q: Can I see Polaris from the Southern Hemisphere?

A: No. Polaris sits above the North Pole, so it is below the horizon everywhere south of the equator. Southern observers use the Southern Cross to find south instead.

Q: Does Polaris move during the night?

A: Barely. It sits less than a degree from the celestial north pole, so it traces a tiny circle in the sky while all the other stars appear to wheel around it.