A variation of the sun compass is a line drawn on a piece of wood with a vertical nail in the center, aka: sundial. Pick a course where you can easily run its reciprocal. Approximate N-S and E-W runs will result in fewer corrections if compass compensators are N-S and E-W.

1. Place the sundial in the sun and rotate the shadow of the nail until it falls on the pencil line. Note indicated compass heading.

2. Without moving sundial, alter course until shadow of the nail falls on opposite side of line. Note indicated compass heading.

3. Take difference of two compass headings, subtract from 180 deg, and compensate compass for half that amount. Compensate higher if difference was less than 180 deg, lower if difference was more than 180 deg.

4. Alter course until shadow of the nail falls on opposite side of line again to recheck prior adjustment.

5. Repeat steps 1-4 for course 90 deg from original.