Diptych dial for latitudes 42°-55° North. Rectangular wooden dial faced with paper comprising two leaves that fold together when not in use. On leaf Ia is a table of latitudes in two columns, listing towns in the USA, England, Spain, France, Italy and Germany. On leaf Ib is an oval vertical dial with a latitude scale for the adjustment of the string gnomon and the signature, 'Stockert a Bavaria'. The compass, on leaf IIa, has three concentric hour scales for the horizontal dial set around it. The magnetic variation is marked at 20° West of North and the string gnomon is broken. Leaf IIb is blank.

The quality of work on this dial is very poor. The wood is not finished and part of the innermost scale of the horizontal dial has been cut away. Although the list of latitudes extends as far south as New Orleans and the latitude scale on leaf Ib has holes for points down to 34° North, the scales on the horizontal dial only allow use down to 42° North. Any readings taken for latitudes in the 30s, therefore, would not be very accurate. It appears that the paper designs were published by Stockert and then stuck onto the diptych by an amateur - possibly the maker. A similarly poorly finished dial is in the British Museum (registration no. 1902,4-12.5).

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