12. Diptych dial by Georg Hartmann, Nuremberg, 1562

Type: instrument
Inv. No. 81528
Source: MHS

Nuremberg was known for the manufacture of instruments and none was more characteristic than the ivory diptych dial. This example, by the celebrated Hartmann, is unusual and perhaps appropriate to a maker with a deeper engagement with mathematics and astronomy than his colleagues. This is not a run-of-the-mill dial: the typical horizontal instrument is absent (so here the characteristic string gnomon is not missing, in fact it is not relevant) but there are a polar dial on the outer face of the upper leaf and an equinoctial dial on the inner face. In the latter case this leaf is set parallel to the equator, in the former parallel to the axis of rotation of the heavens, while the prominent compass helps facilitate these settings, which are at right-angles to each other.

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