Our Renaissance-style perpetual calendar has an effective range of almost 1200 years, from the year 1600 to 2700 . It has two faces: the first is a partial reproduction of Planisferium Copernicanum, and on the other side we see a compass rose and the portraits of Galileo and Newton.
Is made of bronzed metal and is accompanied by a booklet with the history and use.
Note: This perpetual calendar uses the traditional and historically accurate "Dominical letter" system.
"Dominical letters are letters A, B, C, D, E, F and G assigned to days in a cycle of seven with the letter A always set against 1 January as an aid for finding the day of the week of a given calendar date and in calculating Easter.
A common year is assigned a single dominical letter, indicating which letter is Sunday (hence the name, from Latin dominica for Sunday)."
So, for example, 2015 is D, meaning that D days are Sunday.