The outer side of the upper leaf has a polar dial held by a cherub standing on a grid. The dial has hours marked from 5 to 7 and the sun declination is indicated by the symbols of the zodiacal signs. A star mark is in one of the squares of the grid where the cherub stands. A letter 'M' is marked at the bottom and there is a later inscription 'Polare Astronomica' written in black ink. The inner side of the upper leaf is extensively decorated in red and green with geometrical motifs and is inscribed '[star] GEORGIVS HARTMAN [star] [star] [star] [star] NORENBERGE [star] FACIEBAT [star] [star] ANNO [star] DOMINI [star] M [star] D [star] LXII [star]'. Below the inscription is a pin gnomon dial (pin missing) with a sun effigy in the centre and common hours marked from 5 to 12 to 7. In the spandrel spaces are cherub heads, and on the right-hand side is an unequal scale of latitudes marked from [0?] to 70?, divided to 2? and numbered by 10?.
The inner side of the lower leaf has a compass (glass and needle missing) with eight winds named 'TRAMONTA', 'GRECO', 'LEVANTE', 'SIROCHO', 'OSTRO', 'LEBECHIO', 'PONENTE', 'MASTRO'. Surrounding the compass is a calendar scale with the names of the zodiacal signs coloured alternately in red and green, with each sign divided to 2?, numbered from 10? to 30? by 10?. The spandrel spaces are decorated with eight-pointed stars and the names of the cardinal points, and on the right-hand side is the brass arm, decorated with a geometrical motif, for adjusting the latitude. On the borders is the same geometrical decoration as in the upper leaf, typical of Hartmann. On the bottom edge of the leaf is a compartment for stowing the pin, and on the outer side of the lower leaf is a table with 34 towns and their latitudes.
See P. Gouk, The Ivory Sundials of Nuremberg 1500-1700 (Cambridge, 1988).
Ilaria Meliconi