Geographical sundial
OwnerAthelstan Spilhausinventor
Life of this patent
Estimating the term…
Abstract
A sundial comprising a transparent hollow globe marked with latitude and longitude lines and including a map of the world is mounted on a stationary base. The globe is adjustable with respect to the base to enable the polar axis to be inclined toward a geographic pole of the earth and to permit alignment of a desired geographic location on the map with an index point. A reflector is mounted at the center of the globe and focuses an image of the sun onto the interior surface of the globe. The image traverses the globe as the earth rotates, thereby tracking the actual path of the sun with respect to the earth on the globe surface.
Claims11
A sundial comprising
- a transparent, hollow globe having a polar axis and having latitude and longitude markings;
- a base for rotatably supporting said globe with said polar axis inclined toward the geographic south pole of the earth;
- index means secured to said base, said globe being rotatable with respect to said index means to position a selected latitude and longitude on the surface of said globe at said index means;
- reflector means;
- and
- support means mounted on said base and supporting said reflector means, said support means locating said reflector means on said polar axis and at the center of said globe for reflecting an image of sunlight entering said globe to a location on said globe which corresponds to solar noon.
Apparatus for tracking the path of the sun on the surface of a globe, comprising:
- a base;
- a transparent, hollow globe adjustably supported on said base, said globe having a polar axis and carrying latitude and longitude markings;
- reflector means;
- support means for said reflector means, said support means locating said reflector means along said polar axis and at the center of said globe for reflecting an image of sunlight entering said globe having a latitude and longitude corresponding to the instantaneous solar noon, said image traversing the surface of the globe in accordance with the earth's rotation, whereby the path traversed by the sun at true solar noon on the earth is imaged on said globe.
Dependencies are inferred from the claim text.