Parabolic reflector. Simulation of parallel beams of light striking a parabolic reflector. The light beams are brought to a focus in front of the reflector. The ability of parabolic reflectors to concentrate parallel rays to a single focus is crucial in reflecting telescopes (which use huge parabolic mirrors to collect distant starlight). Satellite dishes (and radio telescopes) use parabolic collectors to collect radio waves. The detector is placed at the focus.