Saturday, February 1, 2020

Solar Watch

In 2001, the journal of the North American Sundial Society published a solar watch I designed. Last week I tried to build a working model. The sun A strikes mirror B, and is reflected up a swinging gnomon C. The light is reflected back down to watch face D, to tell the time. Last week's model proved that it would work, but alas, I couldn't find good enough reflectors (required at B and C). It slips into a pocket, or could be scaled down to be worn on the wrist. OBSERVATION: In my paper, I calculated that its accuracy was "better than five minutes in the hour". If scaled up, its time-keeping could be just seconds out, all year round. A great advantage is ease of use, compared with other types of sundial.

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