Hemisferium Perpetual Calendar
The Perpetual Calendar can find any date, day of the week and month from January 1, 1600 to December 31, 2799 including the bissextile years also known as leap years. The original piece on which this replica is designed was made in France between 1650 and 1700 and is kept at the National Maritime Museum in London.
This vertical disc dial has two sides - an altitude sundial and a perpetual calendar, which is the one depicted.
The calendar consists of three rotatable discs set on top of the main disc with a date scale and a lunar age scale among other features that can be adjusted using the instructions to work out what day it was or will be at some point in the future.
The calendar measures 90mm across and is 17mm thick.
Material: Zamak with brass lacquer. Sapele wood tainted with natural wax and polished.
ed with natural wax and polished)