Sun and star time dial

Abstract

A combination nocturnal and sundial celestial timepiece comprising a horizontal base marked with the cardinal points of the compass with a central post having an east-west adjustable pivot at the center of a vertical protractor or latitude scale depending in a vertical plane with spaced oppositely extending legs with aligned apertures for setting the protractor at the latitude of the observer so that the apertures align with the polestar, when the protractor is in the vertical north-south plane. Mounted around and pivoted on a hollow sleeve through the aperture at the upper end of the protractor are a circular date and time dial and a pointer; the outer periphery of which dial is calibrated in the days of the year and can be set for the date with the edge of the protractor and the inner peripheral dial is calibrated in the 24 hours of the day. Either this edge of the protractor or the adjacent end of the pointer may have an arc for compensating the exact longitude time with that of the time zone for indicating on the time dial the zone time of the day. The other end of the pointer diametrical of the dial extends beyond the periphery to provide a notch or aperture through which a pointer star of the Big Dipper may be sighted from the aperture at the lower end of the protractor, so that the pointer reads the time of the night on the time dial. This other end of the pointer also has a gnomon with an aperture therein and, spaced intermediate the ends of the pointer, a post with a central line for alignment of the pointer and the gnomon with the rays from the sun so that when sunlight from the sun shining through the gnomon's aperture falls on the line of the post, at which alignment the pointer will indicate the time of day.