In the front view, the adjustment for the dial's latitude can be seen at the base where the vertical latitude crescent is clamped between the split base casting.
The adjustment for the longitude correction (time zone offset) and accommodation for summer time can be seen where the two crescents meet.
The longitude correction is made by adjusting the the equatorial longitude crescent which carries the time indications calibrated in 5 minute intervals. This view shows the adjustment for the dial's location of 3º (12 minutes) west of Greenwich, when British Summer Time was in effect.
The gnomon can be rotated about its polar axis. When the two wings are set to face the sun equally, the curved slot becomes a straight line, and a broad band of light will pass through it. The center of the band will indicate Local Solar Time on the hour scale.
Curves corresponding to the analemma are formed into the two sides of the slot running through the center of the gnomon.
Assuming the offset scale is set for the longitude correction, the dial can be manipulated to indicate Standard Time (or summer time, if included in the offset), at its location. At each reading, the appropriate wing of the gnomon is turned towards the sun until the narrowest band of light - which will be displaced by the analemmic curves of the slot - falls on the hour scale and indicates the time.
Near the solstices, there is insufficient change in declination to account for the large change in the Equation of Time, so a further adjustment is required via a scale on the back of the gnomon.
Detail of the time indication at 11:30 AM on 28 March. The setting of the offset scale can also be seen in the photograph.
The raw castings were machined by - Tony Moss of Lindisfarne Sundials.
