Vertical cylinder sundial

The column sundial, also known as a cylinder sundial or altitude sundial, consists of a cylinder held vertically and a rotating shadow rod. It was developed by Hermann von Reichenau (1013-1054) and was widely used in the late Middle Ages.

As it was easy to transport, it was often used when travelling. The gnomon can be stored in the cylinder for this purpose.

This sundial is calculated for the geographical latitude of Madrid.