Measuring the Angle to the Sun

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To measure the angle to the sun you need:

  1. A vertical stick
  2. A length measuring device
  3. A sky without clouds blocking the sun

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Often you want to measure the sun’s angle at local solar noon.  The time when the sun is highest in the sky.  You can find the predicted time for your location on TimeAndDate.com.

You want the stick to be vertical.  Use a bubble level to measure this.

Setup before the estimated time and start marking the end of the shadow about every minute.  The shadow will get shorter until local solar noon when it will start getting longer again.  The shortest mark is the distance you want.

Measure the distance from the base of the stick to the shortest mark and the height of the stick.

You can use trigonometry to get the angle to the sun.  Or use this formula:

angle = arctangent ( p / s )

Where:

p is the length of the pole

s is the length of the shadow

Here is an example setup:

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