Diptych dial

Diptych dial for latitude 49° North. This octagonal dial consists of two leaves that fold flat when not in use. Leaf Ia displays a standard lunar volvelle (see related terms) except there is no scalloped edge to the brass disc. The remainder of the leaf is occupied with foliate decoration and there is a single-lined border. Leaf Ib has a vertical dial with blue hour-lines radiating from a central sunface. Various decorative motifs adorn the leaf which also has a double-lined blue border. The string gnomon for use with the vertical dial is missing.

Leaf IIa features a compass surrounded by a double-lined blue border. It is marked with the cardinal points in Latin and is offset 2° East of North to allow for magnetic variation. The needle is in the form of an arrow and surmounted by a brass pyramidal pivot. The glass plate is held in place by a brass ring. The Southern part of the leaf carries a horizontal dial for Italian hours with a brass gnomon. On display are various motifs and there is also a double-lined blue border. Leaf IIb is blank except for Miller's makers mark - a crown. The leaves have a brass hook fastener and a brass hook for holding the dial open. The octagonal shape of this dial is unusual, but it does occur on other dials of Nicolaus Miller (see Lloyd [1992], pp. 75-6, nos 24 and 25).

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

Object Details

ID: AST0163
Collection: Astronomical and navigational instruments
Type: Diptych dial
Display location: Not on display
Creator: Miller, Nicolaus
Date made: 1640-1660
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 7.5 x 39.5 x 50.5 mm

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