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

The bracket carries a latitude indicator and is part of the collar that slides in the centre of the meridian ring. The latitude scale is divided clockwise [0°]-90°-[0°]-90°-[0°] and the reverse side carries a table of latitudes for a few places in Europe and gives the dates for the beginning of the zodiacal signs. Both the obverse and the reverse sides of the equinoctial ring carry the standard hour scale. The obverse side of the declination ring displays the zodiac scale marked by symbols, while the reverse has some faint scratches from trial attempts at engraving.

A thin ring slides inside the declination ring and carries a square with pinholes at each corner. Opposite the sights square is another square with four points indicating the places where the sun's rays should fall when the instrument is correctly aligned. This dial has an unusual transversal scale for the latitudes. It has been used to allow the small latitude scale to be divided more easily into single degrees. The ring inside the declination ring replaces the more normal alidade, which could also be used for measuring altitudes as well as showing the time of day. The quality of engraving is low, particularly on the words in the latitude table.

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