Sundial of the month September

Dam Dial

France

On the occasion of the Year of Astronomy 2009, an enormous sundial was realized on a 100 metres high dam near Castellane in the south of France.
On the occasion of the Year of Astronomy 2009, an enormous sundial was realized on a 100 metres high dam near Castellane in the south of France. Coordinates: latitude 43º 52’ 40” north, longitude 6º 32’ 15” east.

The inside of the dam faces roughly southeast, and gets the sun for the larger part of the day.
The top edge of the dam casts an ever-changing shadow on the curved surface, and the edge of that shadow is the readout line for the sundial.
Where the curved shadow border touches a, likewise curved, hour line, time is read.
This is clearly visible on the last photograph.

The hour line pattern was plotted using laser equipment.
The hour lines were put on the wall in parts, and give the impression of a dashed line.
The engineers fixed the parts while suspended, like mountaineers, from long lines.

Other huge sundial on this site:
Orlando, USA
Tavel, Frankrijk