Which way is north?

Which way is north?

Whether you're lost in the woods or you're trying to install a sundial in your yard, you're bound to want to find true north from time to time, and chances are when the time comes you won't have a compass. What's more, even if you do have a compass, it will point to magnetic north, which, depending on your location in the world, can vary a great deal from true north. So what's an intrepid explorer to do? Read this article to find several different ways to find your way.

Steps

The Shadow-Tip Method

Place a straight stick straight upright in the ground so that you can see its shadow. Alternatively, you can use the shadow of a fixed object that is perpendicular to the ground. Nearly any object will work, but the taller the object is, the easier it will be to see the movement of its shadow, and the narrower the tip of the object is, the more accurate the reading will be. Make sure the shadow is cast on a level, brush-free spot.

Mark the tip of the shadow with a small object, such as a pebble, or a distinct scratch in the ground. Try to make the mark as small as possible so as to pinpoint the shadow's tip, but make sure you can identify the mark later.

Wait 10-15 minutes. The shadow will move approximately from west to east in an arc which depends on your latitude and the season. Mark the new position of the shadow's tip with another small object or scratch. It will likely move only a short distance.

Draw a straight line in the ground between the two marks. This is an east-west line.

Stand with the first mark (west) on your left, and the other (east) on your right. You are now facing aproximately toward true north.

(Accuracy improves as your location approaches the equator, and as the time of year aproaches either equinox.)


Alternative Shadow-Tip Method for Increased Accuracy

Set up stick and mark first shadow-tip as above. For this method, take your first reading in the morning, at least an hour or so before midday.

Find an object or length of string, etc., exactly the same length as the shadow.

Continue taking measurements of the shadow's length every 10-20 minutes. The shadow will shrink until midday, when it is at its shortest. Then it will gradually grow longer.

Measure the shadow length as the shadow grows. Use the stick or object you used to measure the length of the initial shadow. When the shadow grows to exactly the same length as the stick (and hence exactly the same length as your first measurement), mark the spot.

Draw a line connecting the first and second marks as above. Once again, this is your east-west line, and if you stand with the first mark on your left and the second on your right, you will be facing in the aproximate direction of true north.

(Note: for an exact reading, your two marks need to be made at exact intervals before and after noon where you are, which means when the sun is at its highest point in the sky. Any deviation from this leads to inaccuracy.)


Watch Method: Northern Hemisphere

Find an analog watch (the kind with hour and minute hands) that is set accurately. Place it on a level surface, such as the ground, or hold it horizontal in your hand.

Point the hour hand at the sun. You can use a stick to cast a shadow to aid in your alignment if you wish, but it is not necessary.

Bisect (that is, find the center point of) the angle between the hour hand and the twelve o'clock mark (the number 12 on the watch). The center of the angle between the hour hand and twelve o'clock mark is the north-south line. If you don't know which way is north and which south, just remember that no matter where you are, the sun rises in the east and sets in the west. In the northern hemisphere the sun is due south at midday. If your watch is set to daylight saving time bisect the angle between the hour hand and the one o'clock mark instead.

Watch Method: Southern Hemisphere

Use an analog watch as above, and point the watch's twelve o'clock mark (the number 12) toward the sun. If your watch is set to daylight savings time, point the one o'clock mark toward the sun.

Bisect the angle between the twelve o'clock mark (or one o'clock mark if using daylight saving time) and the hour hand to find the north-south line. If you're unsure which way is north, remember that the sun rises in the east and sets in the west no matter where you are. In the southern hemisphere, however, the sun is due north at midday.

Using the Stars: Northern Hemisphere

Locate the North Star (Polaris) in the night sky. The North Star is the last star in the handle of the Little Dipper constellation. If you have trouble finding it, find the Big Dipper. The two lowest stars in the Big Dipper (the outermost stars of the cup of the dipper) form a straight line that "points" to the North Star. You may also find the constellation Cassiopeia, which is always opposite the Big Dipper. The North Star is located about midway between the central star of Cassiopeia and the Big Dipper (see figure).

Draw an imaginary line straight down from the North Star to the ground. This direction is true north, and if you can find a landmark in the distance at this point, you can use it to guide yourself.

Using the Stars: Southern Hemisphere

Find the Southern Cross constellation. In the southern hemisphere, the North Star is not visible, and no single star always indicates north or south, but you can use the Southern Cross as your guide. This constellation is formed by five stars, and the four brightest stars form a cross that is angled to one side.

Identify the two stars that make up the long axis of the cross. These stars form a line which "points" to an imaginary point in the sky which is above the South Pole. Follow the imaginary line down from the two stars five times the distance between them.

Draw an imaginary line from this point to the ground, and try to identify a corresponding landmark to steer by. Since this is true south, true north is directly opposite it (behind you as you are looking at the point).

Moon Method

Observe the moon. If it is not a full moon and rises before the sun sets, the illuminated side is west. If the moon rises after midnight (standard time) the illuminated side is east. This is true everywhere on Earth.

Approximate north and south based on the rough east-west line of the moon. No matter where you are, if you are standing with the west side to your left, true north will be straight ahead.

Tips

These methods may require practice to perfect, so it's a good idea to try them a couple times when you can check your readings. That way, you'll be able to rely on them if you're in a survival situation.

Warnings

The shadow-tip methods are not recommended in the polar regions, which are latitudes above 60° in either hemisphere.

The watch method is not recommended in lower latitudes, particularly below 20° in either hemisphere.

The North Star becomes higher in the sky the further north you travel, and it is not useful about 70° N latitude.

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