Combining the Function of a Sundial and Compass

A sundial compass is a combination of these two instruments, consisting of a portable sundial which is attached over a compass via a hinge. There are some adjustable legs that need to be used to level the instrument if not on level ground. The gnome is hinged and needs to be put in the up position where it locks into place. There should be what looks like a protractor that is to the right of the gnome that is on a hinge, and this needs to be flipped up as well. The protractor is used to set the sundial to the correct latitude angle, while the compass is used to find true north based on the area’s magnetic north declination.

Once your sundial compass has been leveled, set to the correct latitude, and to true north, a shadow will be is cast onto the sundial’s face by the gnome. For use in the southern hemisphere, the same procedure is followed with the exception that true South must be found instead of true North.

Storing & Transporting our Sundial Compass

When the instrument is not in use, the needle brake should be set to ensure that the needle bearing is not damaged in transit. To accomplish this, the lever on the side of the compass is simply slid over, locking the needle in place. Then, the sundial and gnome are folded over for storage.

Allowing for Location in Your Sundial Compass “Reading”

The time shown on the sundial may not match the time on your clock or watch, however. This is because the time shown on the sundial is actually the “local apparent time” due to the fact that times are based on the position of the sun at the center of the time zone. The sundial will be ahead if you are on the east side of the time zone and behind if you are on the west side.