Scaphe

The Skaphe is probably the oldest type of sundial. Its dial is set in a half hollow sphere with horizontal edge. When they noticed that the south ( northern hemisphere of the earth ) is directed part not needed, it was often omitted. Thus, the Skaphe was visible even from a distance. The Gnomon punctiform ( Nodus ), to which is usually the top of a vertically or horizontally mounted gnomon was used.

The name Skaphe coined in the 3rd century BC, the astronomer Aristarchus of Samos, whose hollow sphere sundial in the Roman Vitruvius describes around 30 BC in the ninth of his books about architecture. It is designed as a mirror image of the visible celestial sphere.

The Skaphe served the ancient astronomers next time determination also to measure altitudes of the sun - which is why it was also called heliotrope - and thus to the width determination. A similar construction comes from the Babylonian Berossus, who called it Hemispherium.

Literature and sources

• K.Schaldach: Roman sundials. An introduction to the ancient Gnomonik, 3rd edition, Verlag Harri German 2001
• Skaphe, Art Dictionary of P.W.Hartmann

• Sundial
• Historical instrument of astronomy