Imitation butterfield dial for latitudes 40°-55° North. Oval plate with three concentric hour scales, marked for latitudes 55°, 51° and 45° respectively. The central section is engraved with the arms of the Admiralty. The compass is set into the dial-plate at the South end and supports the plate in conjunction with a single leg at the opposite end. The compass has cardinal points marked by English initials and is offset at approximately 5° West of North to allow for magnetic variation. The gnomon is hinged, folds flat when not in use and is engraved with leaves that transform into a bird head at the centre. A bird index marks the latitude. On the reverse side, the gnomon brace is decorated with leaves and flowers, while the base of the compass is engraved with acanthus leaves, flowers and griffins' heads. There is a table of latitudes for a few places in Europe in two columns.

This instrument is a composite facsimile of AST0392 and AST0393, made by apprentices at the Admiralty Research Establishment. The front is based on AST0393, although the coat of arms has been replaced by that of the Admiralty. The back is copied directly from that of AST0392. The signature has mistakenly been given as 'L Rowley' rather than 'I: Rowley'.

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