The Diffraction Limit

Why bigger is sharper

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Diffraction limit $\theta_{\min} \approx 1.22\lambda/D$.
• Below this separation, extra magnification can’t reveal more detail.
• Bigger apertures and shorter wavelengths give sharper images.

Steps

1. Every lens blurs
2. Two stars
3. Mirror size for 0.1″
4. Your own eye
5. An 8-metre giant
6. Hubble’s sharpness