The armillary sphere is a common type of sundial.
Originally, the armillary sphere was not intended as a sundial, but as a scientific instrument showing the composition of our solar system.
In the past, armillary spheres have also been used for navigation.
A disadvantage of the many rings is that their shadows fall on the hour ring, making its readout more difficult.
This is prevented in the ‘open’ armillary sphere.
A fine example is in Zeeland.
