The main features of the Spot-on Sundial are the modern design, the scientific accuracy engineered to provide accurate sun time given the latitude where the dial is installed, and the divided gnomon constructed of two parallel plates with a small air gap. This permits a ray of sunshine to pass through for a few minutes at solar noon.
The London Model is suitable for use between:
Latitude Degree: 51° 30'N
Latitudes Between: 49.75 to 53.25° N
The Spot-on Sundial can be used indoors or out.
The rotating dial plate allows the use of the dial on an indoor window-sill; the base plate is pushed against the window frame, and the dial plate rotated so the sun shines through the slit on the centre line at solar noon. The centre screw is then screwed down to hold it in position.
For use outdoors, a level plinth is established, the base plate is screwed to the plinth, the rotating dial plate set on the base plate, aligned exactly at the next convenient solar noon, the screw tightened to hold it in position as described in our setup page.