This sun compass is delightfully simple. You take a small disc of wood with a short pin in the middle and make sure it is level. Spend the day before sailing marking, at regular intervals, the end of the shadow cast by this pin from the sunlight. Join up these points and you have a gnomon curve, which passes closest to the pin at north. The next day all you have to do is line up the shadow of the pin with this curve at any time and the north point will point to north. Obviously this curve has a limited life as it will change as the sun's declination changes, but in mid June the declination is changing very slowly, so a curve drawn at this time will be accurate enough for orientation for a couple of weeks. In any case, if the curve is slightly out, an error in the morning will be reversed in the afternoon.

On the Bayeux's tapestry, we can see people who are holding an instrument. It's possible that the instrument is a navigation device such as a Sun Compass.

The solskuggerfjol (sun shadow board) mentioned in the History of the Faroe Islands, was used for determining latitude. It was a circular wooden board about 250 to 300 millimeters in diameter. In the center was a gnomon, the height of which could be set to the time of the year. To keep it level, the board was placed in a bowl of water. The shadow of the noon sun was observed. A circle on the board gave the line the shadow should reach if the ship was on the desired latitude. If the shadow was beyond the line the ship was north of this latitude; if inside, the ship was south of it.

Compass card with accessories which was sent with the yachtsmen competing in the two great races, Round Zealand and Round Fynen. They were made to be placed on top of a beer bottle, which should be held with two fingers near the top.

Another object in Groix island (France)
In 1906, a Viking chief’s grave was excavated, in which was discovered this object which appears to be a Sun Compass.