Indian Ocean Rays & Shadows ~ Imaged close to sunset by Stefan Kuna. ©Stefan Kuna, shown with permission.

Atmospheric
Optics

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The sky opposite the sunset is lit rosy pink. Low slanting rays from the last of the sun have coursed a long path through Earth’s atmosphere and been denuded of blues and other short wavelengths by air molecules and small dust preferentially scattering away that light.

Antisolar or anticrepuscular rays and shadows modulate the sky. The shadows from clouds out of the field of view or even beyond the western horizon are all parallel but appear by perspective to converge towards the antisolar point. The shadows show that the sun has already set at sea level and the antisolar point is above the horizon. Below it the dark blue shadow of the earth itself is rising.