Thursday, May 21, 2020

[wyaxtpfi] 24-hour sun clock

Consider a clock with only one hand.  The hand makes one revolution per day.  We describe locations on the clock dial as if it were a compass rose, with North at the top.  Place a picture of the sun at the tip of the hand; we will call our hand the sun hand.  At 6:00 AM, the sun hand points East.  The hand turns counter-clockwise.  At noon, the sun hand points straight up (North).  The hand continues counter-clockwise.  At 6:00 PM, the sun hand points West.  This simulates the sun going from east to west in the sky over the course of the day.

Paint the upper half of the clock face white (corresponding to day) and the lower half black (corresponding to night).  The sun hand travels counter-clockwise through the bottom half of the dial over the course of the night.  Midnight is South.

Far more fancy would be to have the white-black horizon or terminator on the clock face automatically shift according to the actual times of sunrise and sunset on each day.  This would be challenging to do mechanically but not too difficult if everything is a digital animation.  Various things cause the horizon not to be horizontal: where you are in your time zone, daylight savings time.  Or, instead of a terminator line from sunrise to sunset on the clock dial, it could be a pie chart.

No comments :