Armillary sphere

sundialThe Main Path at the ANBG is good for a short vigourous walk. Near the Main Path is an armillary sphere sundial, of silicon bronze, half a metre in diameter. A plaque gives time corrections for reading the sundial.

Armillary sphere sundials, modeled on the celestial or terrestrial sphere, are constructed from three or more interlocking rings which provide support for the rod-like gnomon, which forms the axis of the sphere, and casts the time-telling shadow on the equatorial ring. The equatorial ring carries hour lines marked at 10 minute intervals from dawn ’till dark. The gnomon is set at an angle of 35┬░ to the horizontal (corresponding to the latitude of Canberra) so that its upper end points at the South Celestial Pole.

The ANBG sundial was made and installed by Sundials Australia in Adelaide, which has been commissioned to install sundials in a number of important locations around Australia. John Ward and Margaret Folkard of Sundials Australia have published an interesting article (part 1 and part 2) based on their book Sundials Australia.

Always searching for more sunshine, the British have The British Sundial Society whose site is a mine of information.