Diptych dial for latitude 42°-55° North. Rectangular wooden dial faced with paper, consisting of two leaves that fold flat when not in use. Leaf Ia displays a table of latitudes in two columns, listing towns in the USA, England, Spain, France, Italy and Germany. Leaf Ib has an oval vertical dial, for use at 50° North, and a latitude scale for the adjustment of the string gnomon. On leaf IIa, the compass has three concentric hour scales for the horizontal dial set around it.

A string gnomon, adjustable for latitudes 34°-56° North, is attached between the inner surfaces of the two leaves. The compass is marked with eight points in English and the magnetic variation is marked at 20° West of North. The needle is surmounted by a brass cylindrical pivot. In the compass bowl, the initials 'F.N.' are printed. Leaf IIb is blank. The leaves have a brass push-button fastener. Originally, the dial may have been painted.

This dial is very similar to another in the NMM collection - AST0286 - made by Ernst Christophe Stockert. The paper facings may have been made by Stockert also. Both dials include a large number of ports in the list of latitudes, indicating that the dial may have been designed for sailors or merchants. The town names are almost all given in their English form, suggesting that the instruments (or at least the paper facings) had been made for the English-speaking market.

For more information regarding this dial please refer to the OUP & NMM catalogue, 'Sundials at Greenwich'.