measure time, ingenious objects that by means of the shadow casted by a thread, and with the help of a compass to orientate them, they show us how one day goes by into another
During the middle ages advanced yet portable astronomical instruments were developed: the astrolabe whose functions included that of a sundial.
The most successful portable sundial was called a diptych..
It consisted of two small flat faces, joined by a hinge. .
The gnomon was a string between the two faces. When the string was tight, the two faces formed both a vertical and horizontal sundial. The best material was white ivory, inlaid with black lacquer markings. The best gnomons were black braided silk or linen..
Materials: Wood and Paper
Dimensions: 50 x 80 x 20 mm
Finish: Colour Walnut
How it works: Put the sundial on an horizontal plane and direct it southwards in such a way that the tip of the compass meets the signaled and coloured "N" on the windrose.
. In this positition we will see that the string casts its shadow over the two sundial quadrants showing the real solar time.