Outside the old city wall by the Mühlbach stream stands this impressive ring sphere sundial on a massive stone pedestal. It combines the functions of a polar axis sundial and an equatorial sundial: the daily movement of the sun causes the length and position of the shadow to constantly change, allowing the time to be displayed. This sundial takes special advantage of this phenomenon by indicating the time with the help of its 48 attached pins. When the sun shines, the pin with the shortest shadow shows the current time.

Additionally, the sundial offers another function: when the attached brass rod is aligned with the sun so that its shadow falls parallel to the sundial's polar axis, a vertical shadow line is created on the wide dial. This shadow line allows you to read Central European Standard Time (CET) on the upper scale and Central European Summer Time (CEST) on the lower scale.

These features make the sundial a unique and educational exhibit, vividly conveying both the ancient worldview and precise timekeeping.