An equatorial sundial is made of two objects; a gnomon and a marked dial. When the two are placed perpendicular to one another with the dial’s plane positioned parallel to the equatorial plane, the gnomon casts a shadow onto the dial’s lower semicircle which in turn indicates the hours of the day.
Turville Sun is an equatorial sundial with a difference.
By reducing the surface plane of the dial to an elemental ring, the upper arc of the ring casts a continually moving shadow onto the marked gnomon, which can be used to tell the time. This reversal of roles between the gnomon and the dial where the ‘leading element is in fact being led’ is conceptualised in three individual clusters of markings along the length of the gnomon.
The individual clusters are hour markings corresponding to particular celestial dates. At the top of the gnomon are the hours of the day of the winter solstice; at the base they refer to the summer solstice; and those in the middle refer to the Equinox, with the markings for sunrise and sunset occurring where the gnomon penetrates through the centre point of the dial.
Turville Sun was designed by Ian Ritchie and Karl Singporewala of Ian Ritchie Architects with structural and foundation specifications by Kate Purver of Jane Wernick Associates. It was fabricated by John Desmond with groundworks by Boshers.