be more attractive: How to Find True North Without a Compass

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 changes with your location in the world

EditSteps

EditThe Shadow-Tip Method

Place a stick upright in the ground so that you can see its shadow. Alternatively, you can use the shadow of a fixed object. 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 tip will move mostly from west to east in a curved line.
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 approximate east-west line.
Stand with the first mark (west) on your left, and the other (east) on your right. You are now facing mostly toward true north, regardless of where you are in the world. The illustration shows that the sun and marker at Points 1 is what is happening for Step 2. At Points 2, it shows what is happening for Step 4. This method is based on the fact that the sun moves across the sky from East to West.

EditUsing 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.

EditUsing 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 and the pointer stars as your guide. The Southern Cross 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).

EditUsing the Stars: Equator

The Orion Constellation is visible from both hemispheres depending on the time of the year. It is a permanent feature on the equator.
Look for Orion's Belt. Orion has several prominent stars. The 'belt' (3 stars in a row) runs from East to West. Look for that, it has a 'sword' attached to it.
Project a line From the sword through the middle star of the Belt. That is the general direction of North.
Orion lays across the Equator: the Belt rises & sets at east & West

EditAlternate Shadow-Tip Method for Increased Accuracy

Set up a stick as perpendicular to the level ground as possible and mark the 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 before midday and will grow after midday.
Measure the shadow length as the shadow grows. Use the string or object you used to measure the length of the initial shadow. When the shadow grows to exactly the same length as the string (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 true north.

EditWatch 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.
Bisect (that is, find the centre point of) the angle between the hour hand and the twelve o'clock mark (the number 12 on the watch). The centre 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.

EditWatch Method: Southern Hemisphere

Use an analogue watch as above, and point the twelve o'clock mark (the number 12) of the watch toward the sun. If your watch is set to daylight saving 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.

EditEstimating the Sun's Path

Understand the path that the sun takes. Remember that the sun rises in the general east and sets in the general west. In between, the sun will sweep out an arc to the south in the northern hemisphere, and to the north in the southern hemisphere (always towards the equator). This means that in the very early morning (shortly after sunrise), the sun will be generally east, while very late in the evening (shortly before sunset), it will be sun will be generally west.
- The path of the sun can vary quite a bit depending on the season, especially far from the equator. For instance, in the summer, sunrise and sunset will tend to be further from the equator (more northerly in the northern hemisphere, and more southerly in the southern hemisphere), while in the winter, they will tend to be closer to the equator. Only one the spring and fall equinoxes does the sun rise due-east and set due-west.
- For precautionary measures, familiar with the path of the sun for your area or the area where you will be going before you are in a situation where you have to know it. A helpful and free web tool is available at http://ift.tt/1iHzz8v. In particular, try to learn the shape of the path at the two solstices, and the approximate time of sunrise and sunset for these two paths. Knowing this information ahead of time can help you estimate the path for the current day.
Find north based on the direction of the sun. If you determine that the sun is in the east (early in the morning), then north will be roughly a quarter turn counterclockwise (for instance, if you're facing the sun, then you would turn to the left). If the sun is in the west, then north is roughly a quarter turn clockwise. If the sun is in south, then north is directly opposite it.
- Around 12 noon (depending on day light savings time and your position within the timezone), the sun will be pointed due south in the northern hemisphere, and due north in the southern hemisphere.

EditTips

When trying to locate the North Star it is important to remember that, despite popular belief, the North Star is not the brightest star in the sky. The only remarkable thing about it is that it is the only star in the sky that does not move.
If you only have a digital watch, you can still aim the watch accurately at the sun, as you figure out where the hour hand will be. Use 12, 3, 6 and 9 o clock's angles to guide you to the other hours, smaller increments for half/quarter hours.
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.
If you have a 24h dial on your clock (like many pilot watches), then just point the hour hand at the sun, and north is at the 0/24h mark.
Halfway between the 12 (use the 1 instead if you're set to Daylight Savings Time ) and the hour hand is the North-South line. At Noon/midday, in the Northern Hemisphere, the sun is due-South; in the Southern Hemisphere, it's due-North.
If using the shadow method, the longer you wait the more the shadow moves and the more accurate it becomes.

EditWarnings

The North Star becomes higher in the sky the further north you travel, and it is not useful about 70° N latitude.
The watch method is not recommended in lower latitudes, particularly below 20° in either hemisphere.
The shadow-tip methods are not recommended in the polar regions, which are latitudes above 60° in either hemisphere.

EditRelated wikiHows

EditSources and Citations

source How to of the Day http://ift.tt/1yLrFIU

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mercredi 13 janvier 2016

How to Find True North Without a Compass