The Sundial Primer – Azimuthal or Azimuth Sundial

The Sundial Primer – Azimuthal or Azimuth Sundial

The azimuthal dial indicates the time by the sun's direction. The dial must be designed for a particular latitude. Figure 1 illustrates a dial that is designed to indicate Local Apparent Time (LAT). The hour lines appear as curved lines on the horizontal dial plate amongst the circular date lines. The gnomon is a vertical pin located at the centre of the dial. The dial must be positioned on a horizontal surface and orientated in the north-south direction as shown in the figure. The time is read by noting the hour line that the gnomon's shadow intersects for a particular day.