Stage 5

The objective here is to rotate the moon once on its axis in one synodic month (29.53055 days). A bracket attached to the moon’s wheel (118) carries pinion 8* around the perimeter of wheel 160. The drive to this pinion is the difference between the rotational speeds of wheel 160 and wheel 118 - i.e. roughly 1/29 of a turn per day. Pinion 8* is connected to a worm with the equivalent of 2 teeth which drives pinion 8 which is connected to a further worm. The latter has the equivalent of 2 teeth and drives pinion 10 which rotates the model of the moon at the required rate. The moon is connected to its shaft by a keyway, so that it must rotate with the shaft but at the same time it can also be slid along the shaft, for the purposes of the next stage.
In 1 day wheel160 turns once and wheel 118 makes 0.96614 turn . Pinion 8* is carried around wheel 160 by a fraction of a turn representing the difference between wheel 160 and wheel 118 which is 1 - 0.96614 = 0.033863 turn per day. So pinion 8* makes 0.033863 x 160/8 = 0.6773 revolutions (in one day) In 29.53055 days, 8* makes 29.53055 x 0.6773 = 20 turns. Hence the Moon makes 20 x 2/8 x 2/10 = 1 turn