Meridian Line of Gueberschwihr

Since ancient times, people have sought to precisely identify midday, the time marking a break and meal. The meridian line, a specific sundial, determines this exact moment called true noon or solar noon. Unlike traditional sundials, it only shows noon, when the Sun is at its highest point in the sky, due south.

These meridian lines, still visible on some buildings, were mainly used to set mechanical clocks in church towers, town halls, and other public buildings, whose mechanisms were then unreliable and prone to irregular movements. In Alsace, two types of meridian lines stand out: the Ungerer models, mostly found in Bas-Rhin, and those made by clockmaker Urbain Adam from Colmar. The most famous is the one designed by J.B. Schwilgué, installed on the south facade of Strasbourg Cathedral, where it helped regulate the renowned astronomical clock.