Horizontal dial

Portable horizontal dial for latitude 45° North. The dial is rectangular and is engraved on its obverse side only. Hours are marked around the edge. Lines of solar declination are shown as dotted lines for the first points of each zodiacal sign: the dial is marked for Cancer to Sagittarius on the morning side and Capricorn to Gemini on the afternoon side. Italian hours are marked by double lines and almucantars of the sun are shown where they lie within the Tropic lines (for finding solar altitude). The remaining space is occupied by floral decoration. It has a shaped hinged gnomon, folding flat when not in use.

The compass has engraved arrow marks for the magnetic variation at 2° East of North. The needle is in the form of an arrow and surmounted by a brass pyramidal pivot. Four turned brass feet support the dial. The dial has a brown leather rectangular case with a tooled fleur-de-lys pattern, a faded red hessian lining and two brass hook fasteners.

Assigning a country of origin to this dial is complicated by the fact that while the decoration on the plate is typically French, the style of numbering (particularly the Z-shaped twos) is German. It seems to be most likely that the ornamentation was added later and that the original instrument was German. There does not appear to be a nodus for use with the Italian hours, but it is possible that the tip of the gnomon serves this purpose.

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

Object Details

ID: AST0490
Collection: Astronomical and navigational instruments
Type: Horizontal dial
Display location: Not on display
Creator: Unknown
Date made: 1700-1750; 1700-50
Credit: National Maritime Museum, Greenwich, London, Caird Collection
Measurements: Overall: 11 x 120 x 172.5 mm
Parts: Horizontal dial