Universal equinoctial ring dial for latitudes 0°-90° North. Standard dial (see related terms) except for the following details:-

The dial is for northern latitudes only and a slider moves in the grooved rim of the meridian ring. The latitude scale is divided clockwise [0°]-90°. On the obverse side and the inner-rim of the equinoctial ring are hour scales. There is a date scale, but no zodiac scale, and the equinoxes are marked at 11 March and 12 September. The gnomon has a pinhole at either end with central concentric lathe-turned circles overlapping the bridge bars. Apart from the unusual double-pinhole gnomon, this dial is typical of those being produced in England in the middle of the 18th century.

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