Dear all, I've reconsidered my previous submission! The sun will not cross from one hemisphere to the other, but will always be in one or the other. It's difficult to explain this without pictures, but you probably all saw this before I did. There is still the slight problem of the two days a year when the sun's path coincides with the dial's plane (perpendicular through the 6 o'clock lines) as then the shadow will be due east or west all day and it will always show 6 o'clock.
The only other consideration is that after the date when the sun is always north of the dial you'll need a different base plate for the dial with the numbers either side of 6 o'clock swapped over. Regards, David Robert Higgon 51°27' N 0°15' W
