Prague Meridian (14°25´17˝) - Old Town Square, Old Town
Old Town Square, Old Town
The need to tell time accurately is much older than the widespread use of clocks; also it took a while before clocks could read time really accurately. In order to determine when the midday is, the so-called Prague Meridian was used from 1652 and could be seen right at 12 a.m. as the shadow of the Marian Column on the paving of the Old Town Square (there was no concept of summer and winter time back then). Accurate Prague time (Tempus Pragense) was in reality determined in the Astronomical tower of Clementinum using a chink sun-dial. From 1842 the midday was announced by waving a flag, between 1891 and 1920’s it was also accompanied by a shot from a cannon located in the castle bastion no. XIX. (After 1928 the astronomical recordings were moved to a new observatory in Ondřejov, the time announcement service stayed in the tower until the occupation; from 1925 the Clementinum observatory provided a time signal for the radio broadcasting.) The time difference between what was recorded at the Clementinum observatory and the Meridian marked out by the shadow of the Marian Column was a mere one second and hence completely negligible in daily life. – Prague Meridian is marked out near the John Huss memorial by a metal stripe, a line paved with different types of cobblestones and a metal plate which says MERIDIAN, ACCORDING TO WHICH TIME IN PRAGUE WAS DETERMINED / MERIDIANUS QUO OLIM TEMPUS PRAGENSE DIRIGEBATUR, placed there in 1990’s.