Light through a round hole doesn't make a sharp dot — it spreads into a bright central disk ringed by fainter halos: the Airy pattern. This is the fundamental limit on the sharpness of every lens, telescope and eye. Shrink the aperture and the rings swell.
◉ Face-on view of the screenIntensity → brightness · radial profile at right
Setup
Aperture diameter a0.20 mm
Screen distance D2.00 m
Wavelength λ520 nm
sinθ₁ = 1.22 λ / a
6.34mm
First dark ring radius
Airy disk ∝ λ/aRayleigh limit
Exposure
Try this: switch to Linear exposure to see the pattern as a camera records it — the central disk holds ~84% of the light, so the outer rings almost vanish. Enhanced gamma-lifts the faint halos back into view.