Moon phase display for a clock

drawing of the moon phase display
A work in progress. The moon is a ball of tissue paper, the final version will be wood. It is painted half black, half white, and has a black background. The wheel has 59 teeth (that is 2 x 29.5.) Every 12 hours it is nudged to the left, one tooth at a time, by the horizontal wire which is driven to and fro by an eccentric on the hour hand of the clock. On the far side of the wheel, not visible in the picture, is a pawl which prevents the wheel turning backwards.
      A lunar month is actually more than 29.5 days, (to be precise 29.530587981 days.) So the display looses about 30 seconds a day, that is, about one day in 2 ½ years.
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