This dial consists of a circular brass box with its lid. On the top of the lid is a nocturnal with the symbols of the zodiac signs and a decoration of dots on the border and small punches on the inner circle. The folding hour-ring has engraved common hours numbered from IIII to XII to VIII.
The compass, which occupies the whole of the box, has engraved the initials of the cardinal points 'S', 'OR', 'M', 'OC' and a half moon in the centre.
The hour ring was set for the latitude by placing the point of the gnomon in a depression on a cross bar over the compass.