Patent ID: 7114262

Claim:
A horizontal sundial apparatus for finding time based on shadow to the nearest minute at a given location comprising: (a) means providing a horizontal surface which is reflective and hard but etchable or inscribable and has a gnomonic projection map centered on the location for which it is made and having a time scale and equation of time scale, (b) means providing a wire gnomon stretched above the gnomonic projection map between a map-pole position and an elevated position at an angle corresponding to latitude of the sundial's given location to point to the Northern axial point of the Heavens a Northern Hemisphere location or Southern Cross for a location South of the Equator and coordinated with the map to provide a shadow of the wire that indicates noon on the map, and (c) a further indicator, formed as a bead along the length of the wire gnomon arranged at the universal point and marking by its shadow on the map, where the sun is directly overhead on a given date.