Astronomical Images : Polyhedral sundial

Albrecht Duerer

Astronomical Images

<p style='text-align: justify;'>Albrecht Duerer (1471-1528), now widely famed for his painting, engraving and printmaking, was interested and proficient in the mathematical arts. In his <i>Institutiones geometricae</i> he married the mathematical art of geometry to the art of perspective and drawing, bringing Euclidean principles to bear on the theory and practices of visual representation. This figure shows a polyhedral sundial, with several sides of the solid bearing a dial of one sort or another. The successful operation of sundials depends upon the maker ensuring particular orientations between parts of the instrument and parts of the heavens and Earth, and some features of sundials can be identified by analogy with certain features of the sphere. The upper figure is simplified so as to emphasise the relevant features of the Earth ' the meridian, the horizon and the axis of the Earth. In the lower figure, as well as representations of the scales and gnomons of the dials, further labels referring to features of the Earth, such as the <i>Contra polum arcticum</i> or '[The surface] facing the Arctic pole', have been added. By portraying the dial as a model of the Earth in this way, the practice of making dials was bound up with theoretical understanding of the doctrine of the Sphere.</p>