07 June (Germany, Democratic Republic ) within release Preciously Sand glasses and Sundials goes into circulation Mini Sheet Horizontal-Tischsonnenuhr face value 8*20 East German pfennig
Mini Sheet Horizontal-Tischsonnenuhr in catalogues | |
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Michel: | Mi:DDR 2798 KB |
Yvert et Tellier: | Yt:DDR 2441a |
Mini Sheet is horizontal format.
Exhibits from The State Mathem.-Physical Salon im Dresdner ZwingerMini Sheet Horizontal-Tischsonnenuhr it reflects the thematic directions:
A sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat plate (the dial) and a gnomon, which casts a shadow onto the dial. As the Sun appears to move through the sky, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time of day. The style is the time-telling edge of the gnomon, though a single point or nodus may be used. The gnomon casts a broad shadow; the shadow of the style shows the time. The gnomon may be a rod, wire, or elaborately decorated metal casting. The style must be parallel to the axis of the Earth's rotation for the sundial to be accurate throughout the year. The style's angle from horizontal is equal to the sundial's geographical latitude.