Caustics: Light and a Glass of Water; Our Sun and Our Atmosphere

December 20, 2023

Caustics 011223 11

Solar halo  tangent arc and zenith arc 101013 013 annotated

Photographer: Photography Class, Southern Maine Community College 

Summary Author: John Stetson    

Caustics are a significant element in the composition of Andre Kertesz’s 1917 photo, “Underwater Swimmer.” Though often seen in shallow streams and pools, caustics can be found whenever rays of sunlight intersect and converge, resulting in areas of enhanced brightness.

To let my students directly observe caustics, a glass of water was placed in sunlight (top photo). Another place to see "caustics" is in the sky (bottom photo, taken on October 10, 2013, from near Portland, Maine).


Portland, Maine Coordinates: 43.6591, -70.2568

Related Links:

Caustics in the Virgin River, Utah