Depth from Diffraction During a Solar Eclipse

Abstract

Greg Passmore

For fun, we can use the Huygens-Fresnel Principle to calculate depth to a partial occluder (like a leaf on a tree), where every point on a wave front from the occlude edge can be considered as a secondary source of spherical waves. This only works in any useful sense with point emitters (solar eclipse, artificial lighting, RF emitters). These secondary waves propagate outward from their respective partial occlusion points in all directions. The sum of all these secondary wavelets at any given point and time determines the shape and behavior of the overall wave front. So guess what, we can measure that and work back to distance!

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