How Do You Calculate Sun Angles?

Calculating the angle of the sun from the horizon requires measuring tools and some mathematical calculations. This experiment works best on a bright day, when the sun creates a distinct shadow.

Find a stick that can be driven into the ground sturdily enough to stand upright. Using a meter stick or a tape measure, measure the length of the stick and the length of the shadow it casts. Record length measurements in whichever system is easiest, just be sure that the same system is used for both measurements. Also, be sure to note the month and time of day. To calculate the sun's angle, divide the length of the stick by the length of the shadow. Next, find the inverse tangent of that value - use tan^-1 for the inverse tangent. If using a scientific calculator, be sure that it is set to degrees and not radians.

Repeating the above experiment multiple times a day, over a course of time, eventually yields a table of sun angle values. Use sun angle tables to provide sun angle calculators. Interested parties simply plug in data on location, time of day and time of year to find valuable information, such as sun height and angle.

Sun angle has a great impact on climate. When the sun's angle is low, the light is spread over a greater area. This is why midday, when the sun is directly overhead and its angle is high, is hotter than morning or evening. Sun angle is also helpful in positioning solar panels for optimum energy yield.