Portable horizontal dial for latitude 48° 20' North. The dial is rectangular and engraved on the obverse side only. The hour scale is depicted on a heart-shaped scroll. There are five consecutive minute scales to allow the division of time to one minute, but many of the graduations have either worn away or were never drawn in the first place. The shaped polar gnomon is set into a nine mm thick strip along the meridian line. There is a hole below the tip to allow for the suspension of a plummet wire, to which is attached an inverted drop-shaped bob which swings over a point marking the horizontal position of the dial.

Franz Jakob Knittl took over his father's workshop in Linz in 1729 (see AST0412). This dial dates from late in his working career, only a year before he ceased trading. Scales allowing the time to be shown to the nearest minute were a speciality of Franz Antoni Knittl, which was clearly continued by his son, Franz Jakob. The dial is signed, 'Ad Elev. Pol. 48 gr 20 min FJ. Knitl 1753'.

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