Quick Answer
A watch can be used for navigation in the field by estimating time, using the watch as a sundial, and by employing the "shadow stick" method to estimate direction and altitude.
Using the Sun for Direction and Time
To estimate time using the sun, note the position of the shadow of an object and use your watch to determine the time. For instance, at noon in the Northern Hemisphere, the sun is directly overhead and the shadow will be vertical. If the sun is at a 30-degree angle above the horizon, it is approximately 10:30 AM. To estimate direction, use the shadow of an object and a stick. Mark the tip of the shadow with a small rock or stick, then wait for 15 minutes. Draw a line between the two marks. The midpoint of the line will be approximately south in the Northern Hemisphere.
Estimating Altitude
A watch can be used as a makeshift altimeter by measuring the time it takes for the shadow of an object to move a certain distance. Hold your watch at arm’s length and note the position of the shadow of the hour hand. Wait for 10 minutes and note the new position of the shadow. The angle between the two positions is approximately equal to 6 degrees. By measuring the distance the shadow has traveled in 10 minutes, you can estimate the altitude. For example, if the shadow has moved 10 feet, you are approximately 100 feet above sea level.
Using the Stars for Navigation
When using a watch for navigation at night, use it to estimate the time and locate the North Star. The North Star is located in the constellation Ursa Minor and is approximately 30 degrees above the North Celestial Pole. By using your watch to estimate the time, you can locate the North Star and estimate your direction. For example, if it is 10 PM in the Northern Hemisphere, the North Star will be approximately due north.
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