A volvelle making a moon dail from the 16th century

I located this make your own Volvelle kit in an 1950s Practical Astronomy book of mine and have enlarged the scans I can only upload jpgs to blog but this can very easily converted to PDF format by any freeware PDF printer writer like Nitro Reader

 A Volvelle was a popular scientific instrument of the 16th century used to calculate the age and phase of the moon for religious festivals the base plate disc 1 is marked with the names of the months and zodiacal signs through which both the sun and moon travel

 On top of this disk is a second disk revolving around the same centre and the index of this is set against the month date of the base plate. The sec ond disk is shown black with a cut out area left white and around the second disk are marked the numbers 1 to 29


 The third disk is placed on top of the second disk matched to centre and this has an index to set to the constellations in which the moon is observed the second disk shows the day phase and turning the two indexes to month and day inside the cut outs of disk 2 the heart shaped figure will show the approximate shape of the moon on disk 3 on that date