Analemmatic dial for 51° 30' North. This dial folds together and carries with it a perpetual almanac. It comprises an ordinary horizontal dial and an elliptical dial. The horizontal dial, numbered IIII-XII, I-VIII, has an eight-point compass rose named by English initials. It is set beneath a hinged brass gnomon. The elliptical dial has a degree scale around its edge and an hour scale numbered IIII-XII, I-VIII. Its East side displays a declination scale while the West side has a zodiac scale. There is a slot along the meridian line to allow the (replacement) steel gnomon to be adjusted for the declination. On the back of the elliptical dial there is a scale along the slit for the times of sunrise and sunset.

The perpetual almanac, titled 'Perpetual Almanacke', comprises two tables. It provides the dominical letters for all of the years between 1697 (thus probably the year it was made, or the year after) and 1758. The dial has a rectangular black sharkskin case.

In 1698,Tuttell published a book entitled 'The Description and Uses Of a New Contriv'd Eliptical Double DIAL; As also of the Universal AEquinoctial DIAL', in which he described the universal equinoctial ring dial and also a new analemmatic dial which he had designed himself. He was also a practising instrument maker and several of his instruments have survived, including the NMM dial, which closely resembles the illustration in the book. Beneath the elliptical dial it is signed, 'Tho. Tuttell Charing + Londini Fecit'.
For more information regarding this dial please refer to the OUP & NMM catalogue, 'Sundials at Greenwich'.