Universal equinoctial armillary dial for latitudes 0°-90° North. The base is supported by three levelling screws. It carries a degree circle, within which the circular plate that supports the dial is free to rotate. It has openings fitted with glass allowing a compass needle to be viewed. The four legs of the dial support are set on the circular plate. The dial-plate, which consists of four concentric discs, is screwed to the latitude arc. One of the discs carries hour scales for marking Italian and Babylonian hours. Attached to the middle rotatable disc are four brackets supporting the ecliptic ring, the outer section of which carries two sights. The inner rotatable disc on the dial-plate carries a set of astronomer's rings. The declination ring is cut through to allow the sun's rays to shine through it. Within these rings is a further ring that carries two shaped pinhole sights, which move along the cuts in the declination ring.

This dial is so similar to AST0166 and AST0167 that it could only have been made by Hauser and Polanski. The rotatable degree scale around the hour scale allows the time to be found for other places if the difference in longitude from the place of use is known. The outer section of the ecliptic ring can be used for measuring the latitudinal eccentricity of the planetary orbits from the ecliptic. Unusually, the date scale on the ecliptic is repeated four times, giving the different scales for the four-year cycle from leap year to leap year. This gives a more precise correlation between the date and the place of the sun in the ecliptic than is possible on most dials.

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