Gnomon of Saint-Sulpice

The obelisk portion of the gnomon of Saint-Sulpice Church, with the meridian line in the middle

The Gnomon of Saint-Sulpice is an astronomical measurement device located in the Church of Saint-Sulpice (Église Saint-Sulpice) in Paris, France. It is a gnomon, a device designed to cast a shadow on the ground in order to determine the position of the sun in the sky. In early modern times, other gnomons were also built in several Italian and French churches in order to better calculate astronomical events. Those churches are Santa Maria del Fiore in Florence, San Petronio in Bologna, and the Church of the Certosa in Rome.[1] These gnomons ultimately fell into disuse with the advent of powerful telescopes.[2]

  1. ^ A journey in Carniola, Italy, and France, in the years 1817, 1818 by William Archibald Cadell p.154 [1]
  2. ^ The sun in the church: cathedrals as solar observatories J. L. Heilbron p.219 [2]