Gnomonic Map Projection Sundial Orbis Solaris

Gnomonics is the science of sundials, which predestines the gnomonic map projection of the world for use in a sundial. In fact, it is the only map projection that is suitable for displaying the subsolar point in a horizontal sundial. Nevertheless, it is rarely seen because it only shows the world map in a highly distorted and incomplete way. In the ORBIS SOLARIS from Helios sundials, the distortion is minimised by refraction in a conical acrylic glass body and the solar event horizon is brought from infinity into a limited circle. This enables a previously unrivalled variety of functions in a sundial. The video clearly explains the gnomonic projection, its extraordinary properties and its convincing use in the ORBIS SOLARIS sundial due to the refraction in the acrylic glass body.