An armillary sundial is based on an ancient device used to measure time based on the location of the sun on the horizon. An armillary uses a shadow stick, or gnomon, to pinpoint the hour of the day. As the sun progresses over the horizon, the shadow produced by the sun will be cast in a clockwise movement. Armillary sundials are both beautiful lawn decorations and accurate timepieces.
Find a flat surface in your backyard. The flatter the surface on which your sundial is placed, the more accurate will be your sundial's time. Avoid placing your sundial in an area that is uneven or bumpy.
Place your armillary sundial on a sturdy mount or pedestal to prevent accidental movement. Use the screws or anchors provided with the mount or pedestal to secure your sundial in place. Position your sundial where it will receive the most direct sunlight during the day.
Ensure that the arrowhead of your gnomon is facing north, as stated by eSunDials.com. Use a compass to help you pinpoint the exact direction of north.
Use a watch to set your sundial. At a particular hour, adjust your sundial so that the shadow made by the gnomon falls on the corresponding number on the hour band.