Field Expedient Techniques

Day Time Field Expedient Techniques

I. Shadow-tip method:

This simple and accurate method of finding directions by the sun consists of four basic steps.

Step 1. Place a stick or branch into the ground at a level spot where a distinctive shadow will be cast. Mark the shadow tip with a stone, twig, or other means. This first shadow mark is always the west direction.

Step2. Wait 10 to 15 minutes until the shadow tip moves a few inches. Mark the new position of the shadow tip in the same way as the first.

Step3. Draw a straight line through the two marks to obtain an approximate east-west line.

Step4. Standing with the first mark (west) to your left, the other directions are simple; north is to the front, east is to the right, and south is behind you.

II. Watch Method.

A. An analog watch can be used to determine the approximate true north and true south. The direction will be accurate if you are using true local time, without any changes for daylight savings time. Remember, the further you are away from the equator, the more accurate this method will be. In the northern hemisphere, hold the watch horizontal and point the hour hand at the sun. Bisect the angle between the hour hand and 12-o'clock mark to get the south line (see top picture in figure below).

Night Time Field Expedient Techniques

I. Using The Moon

Because the moon has no light of its own, we can only see it when it reflects the sun's light. As it orbits the earth on its 28-day circuit, the shape of the reflected light varies according to its position. We say there is a new moon or no moon when it is on the opposite side of the earth from the sun. Then, as it moves away from the earth's shadow, it begins to reflect light from its right side and waxes to become a full moon before waning, or losing shape, to appear as a sliver on the left side. You can use this information to identify direction.

If the moon rises before the sun has set, the illuminated side will be the west. If the moon rises after midnight, the illuminated side will be the east. This obvious discovery provides us with a rough east-west reference during the night.

II. Using The Stars

The Northern Sky

The main constellation to learn are the Ursa Major, AKA the Big Dipper, and Cassiopeia , AKA the Lazy W. Use them to locate Polaris, AKA the North Star. Polaris is considered to remain stationary, as it rotates only 1.08 degrees around the northern celestial pole. The North Star is the last star of the Little Dipple's handle and can be confused with the Big Dipper. However, the Little Dipper is made up of seven rather dim stars and is not easily seen unless you are far away from any town or city lights. The Big Dipper and Cassiopeia are generally opposite each other and rotate counterclockwise around Polaris, with Polaris in the center. The Big Dipper is a seven-star constellation in the shape of a dipper. The two stars forming the outer loop of this dipper are "pointer stars" because they point to the North Star. Mentally draw a line between the outer bottom star to the outer top star of the Big Dipper's bucket. Extend this line about five times the distance between the pointer stars. You will find the North Star along this line. You may note that the North Star can always be found at the same approximate vertical angle form the above horizon as te northern line of latitude you are located on. For example, if you are at 35 degrees north latitude off the horizon, Polaris will be easier to find if you scan the sky at 35 degrees off the horizon. This will help to lessen the area of the sky in which to locate the Big Dipper, Cassiopeia, and the North Star.