Gnomonic possession

ECLIPSE chasers are not the only people who like to follow shadows around. Gnomonists concern themselves with telling the time using a shadow, a lot of mathematics, a stick (called a “gnomon”) and a few carefully ruled lines. In other words, a sundial. At the intersection between history, astronomy, mathematics and craftsmanship, sundials have inspired specialist walks, tours, conferences, magazines and societies. And this year, gnomonics fans are in clover, as millennium sundials sprout all over the world.