Universal equinoctial scaphe dial for latitudes 0-90° North. The dial is mounted on a turned brass column. Fixed to the top of the column by means of two brass clamps is a vertical ring which can be turned to adjust the latitude. It has a degree scale and a zodiac scale. A hemispherical bowl is attached to the latitude ring at the points of the equinox; the bowl is free to turn on its axis. It displays a date scale, a degree scale and is marked by zodiacal symbols. It also shows declination parallels and meridians.
Attached to the rim of the bowl by two brass clamps is a semi-annular arc which carries a degree scale, is adjustable for the date and can also pivot within the bowl. A rectangular rod gnomon is attached to the centre of this arc by means of two screws. The compass is attached to the vertical ring near the vernal equinox and the cardinal points are marked in Latin.
This is a very fine example of an equinoctial dial, with high quality engraving, and was clearly made for a wealthy patron. It is the only equinoctial scaphe dial in the collection (see also AST0214) to include a full hemispherical bowl. The bowl is marked with all the declination parallels up to 80°, despite the fact that the sun never passes beyond the Tropics and so the remaining lines engraved on the bowl serve no useful purpose beyond the decorative.
For more information regarding this dial please refer to the OUP & NMM catalogue, 'Sundials at Greenwich'.
Credit: National Maritime Museum, Greenwich, London. Caird Collection