STUDIES ON THE SHADOW OF AN OBELISK USED AS HORIZONTAL SUNDIAL
A horizontal dial consists of the dial plate marked out with hour and date lines, and a gnomon that casts the shadow. In former times obelisks were used as gnomons. One archetype is the Solarium of Emperor Augustus in Rome, which was built 13 B.C. using the Campus Martius as dial plate. In this workshop the astronomical principles of a horizontal sundial are described combined with solutions for the construction and the design. At the end every participant will build a portable mini version of a horizontal sundial.