Evoulation of Radio Astronomy: The Complete Story.

The age of radio astronomy began from the day when engineers learned to generate radio waves using an electron tube. Approximately after a decade from the discovery two young and dynamic engineers Gregory Breit and Merle Tuve, bounced radio waves off the ionosphere and determined the height of the layers. This proved that radio waves can travel beyond earth and back and they can be used as a probe for communication. 


Two years later a well known American inventor, writer, and magazine publisher Hugo Gernsback popularly known as father of science friction proposed an article "Can We Radio The Planets". The radio waves that can be bounced from the moon and the planets. He also stated that 2.5sec will be required for a radio wave to travel to the moon and back.



In the years of 1930 Karl Guthe Jansky at Bell Telephone Laboratories investigated the noise sources in radio transmission. Jansky used a large directional antenna of 14.6m wavelength which identified three different types of static noise. Noise signal from local thunderstorms, a steadier (ie; firm in position) and weaker static from distant thunderstorm and a weak hiss from unknown source. 

The weak signal from the unknown origin peaked about every 24 hours. Firstly Jansky suspected that this unknown source was sun crossing the view of his directional antenna, but when Jansky compared his observations with the optical astronomical maps, he concluded that the radiation was coming from the Milky Way and it was maximum in the direction of center of galaxy.

But instead of encouraging the research of Jansky; Bell's laboratory rejected Jansky's request to build a 100 foot radio telescope. No other institution followed Jansky's work.

Only after World War II a radio engineer Grote Reber took Jansky's work and continued it as a hobby in his spare time. He built a 31-foot parabolic antenna and in 1937 made the first radio map of the sky. With the intense development of radar technology during the world War II gave a new aid to astronomers. 
 
A team headed by J.H. De Witt of U.S. Army Signal Corps were succeeded in seeing the echoes of the moon on the cathode ray tube .
From then there was no turning back and in the years of 1940-50 radio astronomy emerged as a new branch of astronomy. A 76m steerable radio telescope was built in England at Jodrell bank in 1957. 


While a 305 meter fixed reflector was completed in Arecibo Puerto Rico in 1963. It is the world's largest radio telescope made till date.