The Sundial Compass is a nautical instrument for telling the time of day by the position of the sun, just as any sundial can. However, in the middle of the ocean there is no way of knowing where north is without reference to a magnetic compass. This instrument cleverly combines both, the sundial and a magnetic compass.
The integral magnetic compass allows the sundial to be correctly oriented to north without external reference. The sundial face is hinged, enabling the viewer to set the local latitude against the curved scale on the side. This ensures the sun will cast a shadow from the vane over the face of the dial. It has three adjustable legs that are used to precisely level the sundial before taking a reading.
The hinged elements of the instrument design allow it to be neatly folded flat when not in use and a needle lift mechanism to protect the compass needle when in its transport case.
Charlie acquires one of these from Emilie’s Emporium for their journey in Charlie Green and the Pirate’s Treasure.
On my school visits I bring one along for you to see first hand.