## Physics: Principles with Applications (7th Edition)

The Rayleigh criterion, equation 25-7, calculates the resolution limit for a lens/mirror of diameter D when using light of wavelength $\lambda$. The objects are resolvable if they are separated by a minimum angle $\theta$, where $\theta = \frac{1.22 \lambda}{D}$. The smaller the angle, the better the resolution. Using a large diameter lens, all else being equal, improves the resolution.