Une histoire des cadrans solaires en Occident
La gnomonique du moyen âge au xxe siècle
800 sundials of the Antiquity are known and preserved in museums. There are tens of thousands of them in Europe built between the Middle Ages and today. France alone has more than 32,000. The vast majority of them are still in operation on churches, in gardens, on public buildings or on private houses.In A History of sundials in the West, Denis Savoie reminds us of the heritage of Greco-Roman gnomonics and then examines the medieval achievements that reflect the clear decline of astronomy in the West. A profound change began in the measurement of time at the end of the Middle Ages and the beginning of the Renaissance, with the appearance of clocks and the abandonment of ancient timekeeping. The development of mathematics, the diffusion of the first printed works in the 16th century, the increase in the precision of the dials on which clocks are now set, all these factors contribute to massively spread these instruments which will remain for a long time the only way to know the time in the cities and the countryside.Sundials became an inexhaustible field of research and many types were built, from the luxurious pocket portables to the meridian in the cathedrals while passing by the simple dials which decorate the facades. Even if the 19th century relegates them to the background, sundials have never ceased to be at the same time objects of art often decorated with mottos and scientific and educational instruments essential to the understanding of the movements of the Sun.A unique synthesis of gnomonics, this richly illustrated History of sundials allows us to discover all the facets of an instrument that goes back to the beginnings of astronomy. Denis Savoie, historian of science, is a scientific advisor at Universcience (Palais de la Découverte & Cité des Sciences et de l'Industrie) and an associate researcher at the Observatoire de Paris (Syrte). He chaired for twenty years the Sundial Commission.