Angle of Incidence Dial
The angle of incidence determines the percentage of the direct beam a surface receives. Angles of incidence can be represented with concentric circles around a central shadow casting pointer. The shadow of the pointer varies in length with the angle of the dial to the sun and shows the percentage of the available beam directly. There is nothing to calculate. (This is fortunate because the angle of the direct solar beam to a surface has five components—latitude, time of day, date, tilt, and orientation.) Our angle of incidence dial comes with a small adjustable platform on a magnetic base that allows you to match the tilt and orientation of any surface on the deck. As you manipulate the shadow on your sundial diagram to set times and dates, the angle of incidence dial tracks percentages on the surface you have matched.
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