EVERYDAY SCIENCE

Detailed explanation-1: -In a side yard of his mother’s house in Wheaton, Illinois, a 26-year old engineer named Grote Reber built the first dish antenna radio telescope in 1937. He used wooden rafters, galvanized sheet metal, and spare parts from a Ford Model T truck.

Detailed explanation-2: -A radio telescope is designed to detect radio waves from distant sources, while an optical telescope is designed to detect visible light (and sometimes UV or IR radiation).

Detailed explanation-3: -The first purpose-built radio telescope was a 9-meter parabolic dish constructed by radio amateur Grote Reber in his back yard in Wheaton, Illinois in 1937.

Detailed explanation-4: -The main reason that radio telescopes must be big is the diffraction limit (see topic 4 above). Since radio wavelengths are much bigger than optical wavelengths, the telescope aperture must be bigger by the same ratio to give comparable angular resolution.