If a beam of waves passes through a narrow opening, like the optics of a telescope, the beam will be seen to diverge and not just continue in the original direction. This is a consequence of:

Question

Quizplus · Accepted Answer

This phenomenon is known as diffraction, which is the bending of waves around obstacles and through narrow openings. Refraction is the bending of waves when passing through a medium with a different refractive index, reflection is when waves bounce back off a surface, and chromatic aberration is an optical effect where different colors of light are refracted differently and can result in a blurry image.

If a Beam of Waves Passes Through a Narrow Opening