Navigate by the Stars

Before the GPS, before the compass, your main means of finding your way was to navigate by the stars. Although today’s technology makes finding your way easier, it’s still fun to learn how to navigate by the stars. You can find north, south, east, or west by learning a few stars and constellations, or you can simply pick out a star and follow its movements.

Steps

Finding the North Star (Northern Hemisphere)

1. Look for Polaris, the North Star. Polaris is the brightest star in the constellation Ursa Minor, the Little Bear. It can be found in the bear’s tail. (The ancient Greeks, and many other peoples, saw bears as having long tails.) The star is called Polaris because it appears within a degree of the Celestial North Pole and so appears not to move in the night sky.
   • Today, because the seven stars of Ursa Minor look like a small water dipper, most people refer to Ursa Minor as the Little Dipper instead of the Little Bear.
2. Use pointer stars to help you find the North Star. Although Polaris is visible in the northern sky at most locations north of the equator, it can be hard to spot if you don’t know exactly what you’re looking for. You can use stars in other constellations to point the way to Polaris.
   • The most commonly used pointer stars are Merak and Dubhe, the two stars on the edge of the Big Dipper opposite its handle. By following these stars in the direction of the Big Dipper’s mouth, you can find Polaris.
   • During the times of night when the Big Dipper is below the horizon, such as the early hours of fall, you can instead draw a line through the stars at the eastern edge of the Great Square of Pegasus, Algenib and Alpheratz (actually part of the constellation Andromeda), and through Caph, the star at the rightmost edge of the W-shaped constellation Cassiopeia, to find Polaris.

Finding Your Latitude (Northern Hemisphere)

1. Locate Polaris. Use either of the pointer star methods to help you.
2. Determine the angle in degrees between Polaris’ position and the northern horizon. The most accurate way to do this is with a quadrant or sextant, which lets you read the angle off its curved section. This angle measure is the same as your latitude north of the equator.
   • If you don’t have a quadrant or sextant, you can approximate the angle by extending your fist to the horizon and stacking fists hand-over-hand until you reach the North Star. Your extended fist is approximately 10 degrees of angle measure.

Finding South (Northern Hemisphere)

1. Look for the constellation Orion. The constellation Orion, the Hunter, bears a resemblance to a bent hourglass. The stars Betelgeuse and Bellatrix represent its shoulders; the stars Saiph and Rigel represent its knees (or feet). The three stars in the middle, Alnitak, Alnilam, and Mintaka, represent Orion’s belt.
   • In the Northern Hemisphere, Orion is visible chiefly in the winter and early spring, but can be seen late at night in the fall or before sunrise in the summer.
2. Find Orion’s sword, if you can. Look for one moderately bright, one dim, and one fuzzy star hanging down from Alnilam, the middle star in Orion’s belt. This represents Orion’s sword, which points to the south.
   • The fuzzy “star” is actually the Great Nebula of Orion, an interstellar nursery where new stars are being formed.

Finding South (Southern Hemisphere)

1. Look for Crux, the Southern Cross. While there is a star near the South Celestial Pole, Sigma Octantis, it’s too dim to do you much good for finding south. Instead, look for the bright constellation Crux, the Southern Cross, which consists of four stars that form the ends of the cross’ upright and crosspiece.
   • The Southern Cross is so prominent a constellation that it is depicted on the flags of Australia and New Zealand.
2. Extend a line through the long axis of the cross. The point along this line, about four-and-a-half times the length of the long axis is directly above south.
   • (optionally) Improve your accuracy by finding the two "pointers" to the southern cross and drawing a line through them. Then take a line perpendicular from the middle of that and extend it to intersect with the line drawn from the Southern Cross. Where they intersect is directly above south.
   • Drawing a line through the two stars of the crosspiece will point you to the star Alpha Centauri, the closest star to Earth after the sun. (This star is also depicted on the flag of Australia, but not of New Zealand.)

Finding East or West (Celestial Equator)

1. Look for the constellation Orion. As noted before, the torso of the constellation looks something like a bent hourglass.
2. Look for the rightmost star in Orion’s belt. This star, Mintaka, rises and sets within a degree of true east or west.

Finding Direction By Following a Star’s Position (Anywhere)

1. Drive 2 stakes in the ground. The stakes should be about 1 yard (91 cm) apart.
2. Pick any star you see in the night sky. You can use any star for this, although you’ll probably want to pick one of the brighter stars.
3. Line the star up with the tops of both stakes.
4. Wait for the star to move out of position with the stakes. Earth’s rotation from west to east causes the stars in the sky, as a whole, to rotate from east to west. Which way the star has moved with respect to its original position where you sighted it tells you which direction you’re facing.
   • If the star rose, you’re facing east.
   • If the star sank, you’re facing west.
   • If the star moved to the left, you’re facing north.
   • If the star moved to the right, you’re facing south.

Tips

• Polaris is one of 58 stars used for celestial navigation by aviators and navigators worldwide. Some versions of the list exclude Polaris because its nearly-fixed position enables it to helps navigators find their latitude without needing to know the position of any other star.
• The Big Dipper, known in England as “The Plough” or “Charles’ Wain” (Wagon), is part of the larger constellation Ursa Major, the Great Bear. It can be used to find other stars besides Polaris. Drawing a line through the pointer stars Merak and Dubhe away from the Little Dipper leads to the bright star Regulus in the constellation Leo, the Lion. Drawing an arc from the stars in the Dipper’s handle leads first to the bright star Arcturus in the constellation Bootes, the Herdsman, and then to the bright star Spica in the constellation Virgo, the Virgin.
• Don't be fooled by thinking that Polaris ( The North Star ) is the brightest in the sky, In fact, it is only the 48th brightest star we know of, The brightest star is Sirius ( The Dog Star ) in the constellation Canis Major.

Warnings

• The instructions for finding directions using reference stars will gradually become dated due to the precession of Earth’s axes, which changes the direction in which the planet’s north and south poles point. This will cause different stars to move closer to the Celestial North and South Poles. Polaris will only be the North Star for another few hundred years, as the Celestial North Pole moves in the direction of the constellation Cepheus. The instructions for finding your direction by following a star’s position over time will still work as long as Earth continues to rotate west to east.

Sources and Citations

See also

• Stay Safe While Boating
• Survive if Lost at Sea
• Stay Safe on a Casino Cruise
• Equip Your Boat for Safety
• Salvage a Wrecked Ship
• Recover a Man Overboard when Sailing a Dinghy
• Use a Marine GPS
• Avoid Dangers when Paddling a Kayak or Canoe
• Be Safe During a Cruise Ship Fire
• Make a Float Plan

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