How was the first radio telescope developed?
A radio telescope is a highly directional radio antenna that is able to create a map of the sky by recording signals coming from different directions. Although radio engineer Karl Jansky was the first to identify deep space radio signals in 1931, his antenna was not good at pinpointing individual sources. The first steerable radio telescope was built in 1937 by Grote Reber, who had applied to work with Jansky but was turned down because of the poor economic times. So he decided to build his own radio telescope, a 31.4-foot metal dish (9.6 meters) mounted on a directional cradle in Wheaton, Illinois. With his radio telescope, Reber was able to detect radio emissions from the Sun, the center of the Milky Way Galaxy, and several other “radio-bright” sources. By 1941, he had completed the first crude radio survey of the northern sky. Today his radio telescope is an historical monument in Green Bank, West Virginia.
