Quick Answer
To use a shadow stick to find true north, locate a straight stick or branch and mark its tip with a small notch. At the same solar time on two consecutive days, observe the direction of the shadow cast by the notch and draw a line connecting the two shadow endpoints. The midpoint of this line indicates south.
Preparing the Shadow Stick
To create an effective shadow stick, look for a straight branch or stick with no knots or twists. Cut the branch to a length of about 2-3 feet, which will provide a stable and clear shadow. Mark the tip of the stick with a small notch or groove, using a knife or a rock. This notch will serve as a reference point for measuring the shadow’s movement.
Measuring the Shadow
At the same solar time on two consecutive days (ideally around noon or 1 pm), place the shadow stick vertically in the same location. Mark the end of the shadow cast by the notch with a small stick or rock. Repeat this process on the second day, at the same solar time, and mark the new shadow’s endpoint. Draw a line connecting the two shadow endpoints, making sure to extend the line beyond the shadow’s endpoints.
Identifying True North
The midpoint of the line connecting the two shadow endpoints will indicate south. To find true north, simply extend an imaginary line through the midpoint in the opposite direction. Use a compass or other navigation tools to verify the direction. Keep in mind that this method relies on the Earth’s rotation and the shadow’s movement, so it’s essential to maintain accurate measurements and timings.
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