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

The bracket is attached to a collar which slides in the grooved outer rim of the meridian ring. A protruding pointer on the bracket acts as a latitude indicator. On the meridian ring is a latitude scale and a table of latitudes primarily featuring places in Germany, which continues on the reverse. This table is further continued on the obverse side of the equinoctial ring, which has an hour scale on its reverse. The declination ring has a zodiac scale on its obverse and the rest of the table of latitudes on its reverse. Attached to the declination ring are two crossed supporting struts, mounted on which is the alidade. On this are pointers which move over the declination scale to indicate the position of the sun in the ecliptic. Two simple sights are set close to the ends of the alidade, one with a pinhole which, when the instrument is positioned correctly, will allow the sun to shine on a corresponding marked point on the other 'sight'. The dial is signed 'Johann Martin Willebrand. in Augsburg' on the meridian ring.

A delicate version of this type of instrument, this dial has a very high quality of engraving, typical of Willebrand's style. The pinhole on the alidade is set to one side, rather than in the centre, so that it does not become obscured by the meridian ring at noon.

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