Prof Paul Callanan pictured with the equatorial telescope in the Crawford Observatory, UCC, which was manufactured by Howard Grubb. It tracks the motion of the stars using clockwork - just the same as Grubb’s “coelostat” device, which was used during the eclipse of 1919. Photograph: Andrew Bradley

A total eclipse of the Sun 100 years ago today – on May 29th – provided the first evidence in favour of Einstein’s theory of general relativity. It g(...)