The Seventh Sundial

This handsome acrylic and vinyl dial declines 73* west of south, which means it can record the afternoon hours, theoretically till sundown.

However, shadows from the building opposite mean that it is best appreciated in the summer months. As the sun's height increases the shadow of the rod (or gnomon) can be seen on the face for a longer period each day, indicating what is known as 'local solar time'.

Whilst clock days are all the same length, solar days vary in length, due to the earth's elliptical orbit around the sun, and the tilt of its axis. This difference is known as the 'equation of time' and is shown on the graph below.

To obtain clock time or GMT, on any day you should read the line on the dial and add or subtract the number of minutes given for the current date on the graph. Add an extra hour when BST is in effect.

Our sundial was made by Ray Ashley, designed by John Moir.

For further information on sundials, contact the British Sundial Society.