The
SpotOn Sundial is easy to read. The shadow of the top slanting
edge of the gnomon travels round the sundial in a clockwise
direction.
This shows the shadow falling exactly on an hour line.
The time is 8 am winter time (indicated by the VIII Roman
numerals) or 9 am in Summer Time/ Daylight Saving Time
An hour and ten minutes has passed. The shadow now falls
on the first of the small lines indicating 10 minutes past
the hour. The time is 9.10 am (or 10.10 am in Summer Time)
Nine
minutes later, the shadow has passed the spot indicating
a further five minutes, and is considerably closer to the
next tenminute line than to the spot. The time is 9.19
am (or 10.19 in Summer Time
And so we reach the time of solar noon (12 in winter and
1 pm in summer) with the line of light shining through the
air gap, and directly across the the circle.
The Unique Line of Light
Note that the times given in this page are local times
by the sun. The difference between your local time and the
time on your watch depends on your longitude and the Equation
of Time, as described in our local
time page
