This scientific instrument was built to mesure the movements of the earth’s axis of rotation.
  

Commissioned by Languet de Gergy, the astronmical gnomon was built by English clockmaker and astronomer Henri de Sully in order to determine the exact dates of Easter and the equinoxes.

Go to the index page of pictures of Saint-Sulpice church.

Take a look at the pictures I’ve taken on trips to Italy

See the pictures I’ve taken in the United States

Take a look at the photographs I’ve taken in Canada