Back to results
US 6,604,290 B1Granted
Sidereal sundial
OwnerThomas R. Hughes, Jr.inventor
Life of this patent
Estimating the term…
Abstract
By adding an opaque ecliptic half-plane (24) to a partially open or transparent equatorial disk (12) which bears a sidereal hours scale (20), and by being able to rotate this plane (24) and disk (12) jointly in order to minimize the shadow being cast (74) by ecliptic half-plane (24), one can easily determine the local sidereal time using the sun. Understanding its operation draws on a number of basic concepts that a beginning astronomy student should master, and should also interest sundial enthusiasts.
Claims1
A sidereal sundial comprising
- (a) a gnomon,
- (b) a support to hold the gnomon,
- (c) means to align said gnomon parallel with the earth's axis,
- (d) an equatorial disc mounted perpendicular to the gnomon and carrying sidereal time markings (1,2,3, . . . , 23,24),
- (e) a tipped plane mounted on the equatorial disc and making an angle of 23.4° with the equatorial disc,
- (f) joint rotatability of the equatorial disc and the tipped plane about the gnomon, and
- (g) a meridian indicator affixed to the gnomon support and adjacent to the sidereal time markings on the equatorial disc for determining the sidereal time.
4 more elements
Dependencies are inferred from the claim text.