Universal equinoctial ring dial for all latitudes. Standard dial (see related terms) except for the following details:-

A slider moves in the grooved rim of the meridian ring and a suspension ring and ball joint are detached from the dial. The latitude scale is divided clockwise from top [0°]-[90°]-0°-90°-[0°] and 'S' and 'N' are marked at either side of the top zero line. There is a scale for determining the solar altitude and zenith distance and a wheatsheaf design along the inner edge. On the obverse side and on the inner-rim of the equinoctial ring are hour scales. There is a date scale, a declination scale and the equinoxes are marked at 11 March and 11 September. The gnomon has glass in the pinhole.

The wheatsheaf pattern on the meridian ring is one indication of the English origin of this dial. It is similar in style to dials by Edmund Culpeper and Nathaniel Witham, and so probably dates to the first quarter of the 18th century. It is relatively unusual in having a full 360° latitude scale.

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