A Cork Astronomy Club public lecture held in UCC’s Civil Engineering Building
Telling the time is one of the earliest applications of astronomy, and the sundial, the earliest device to tell time of day and divide daylight into hours. James Quain, a member of Cork Astronomy Club with a lifelong interest in sundials, told how these installations work and the astronomy they are based on.
James illustrated how time is depicted, and discussed the development of sundials from the earliest known examples.
Above: James with his Armillary Dial.
A sundial we learnt, consists of two parts: a gnomon to cast a shadow, and a dial plate. We found out things we didn’t know we didn’t know … the extraordinary variety of sundials … James brought his own replica of a portable wooden dial as used by shepherds in the Pyrenees, and a model of the earliest known sundial consisting of two stones ─ another portable device used by the Pharaohs in 1500 BC.
For most sundials (but not the shepherd’s dial) you need to know north. But a solar compass from 1835 works the other way round. It uses two very different sundials (image below), you turn it till they both agree, and hey presto, it’s facing South. The world’s largest sundial is at Jaipur in India, and the smallest consist of two metal rings that those who were rich enough in the 18th century kept in their pocket.
Finally James took grave issue with Hilaire Belloc who wrote “I am a Sundial and I make a botch, of what is done much better by a watch”
Workshop, April 15th
For Club members only, James will give a workshop with work in small groups to make a paper sundial, cut out components and assemble, set up & orientation.