Tuesday, May 22, 2012

Making a Shadow Tip Compass and Sundial

Couple of key items necessary in the bush:  knowing your way, and what time it is.  For those of us without a Rolex and a high-end Garmin with built-in compass, or if your Rolex/high-end Garmin just floated down the river with the rest of your gear but not you, I offer the following:

MAKING A SHADOW-TIP COMPASS


Find a straight stick, approximately 1 meter long, and a level ground spot.

1.  Place the stick into the ground at a level spot where it will cast a distinct shadow.

2.  Mark the shadow tip with a stone or some other marker.  THIS FIRST SHADOW MARK IS ALWAYS WEST, ANYWHERE ON EARTH.

3.  Wait 10-15 minutes, until the shadow moves.  Mark this new position shadow tip with another stone or marker.  This is East.

4.  Draw a straight line through the 2 points marked to obtain your East-West line.

5.  Stand with the first mark (WEST) to your left, and the second mark (EAST) to your right.  You will be facing NORTH.

6.  Mark North-South line, and your compass is complete.



SUNDIAL


1.  Pick an open, sunny area where shadows of trees or other objects will not interfere with the sundial.  Find a place where both sunrise and sunset are visible so the sundial will record time for all daylight hours.

2.  Locate true north.  One way is to stand at night where you will place the sundial and locate Polaris (the North Star).  Push a straight stick (approximately 1 meter long and as straight as possible) into the ground at an approximate 32 degree angle (for us Texas folks), pointed to the North Star, or True North.  Place a small stone or similar marker in line with the North Star, approximately 2 inches beyond and to the north of the end of the stick.  This stone will mark 12:00 noon.

3.  Draw a straight East-West line in the dirt, approximately 2 inches south of the stick.  This line should be about 2 feet long, with one foot on each side of the stick, as centered as possible.

4.  Kneel behind the line, facing north, and place one small stone on the end of each East-West line, then 5 small stones on each side of the 12:00 marker, spaced evenly.  The small stones will form a semi-circle, with 12:00 at the top.

5.  Each stone marker is approximately 15 degrees, the distance the sun travels in 1 hour.

6.  Hour markings for the sundial, from left to right are:  6, 7, 8, 9, 10, 11, 12, 1, 2, 3, 4, 5, 6, and run from 6am to 6pm.



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