Radio Astronomy and satellites
Some limitations of optical telescopes are overcome by the use of Radio telescopes. Radio Telescope detects radio waves that come from space instead of light. Radio waves are a form of electromagnetic radiation. Radio waves are not scattered or blocked by the Earth’s atmosphere. The use of Radio waves to study space objects is called Radio Astronomy.
The radio waves detected by radio telescopes have frequencies that are different fro that of radio stations on Earth. And because it has a different frequency, Astronomer will know it is coming from space.
A radio telescope is usually a radio antenna and a receiver. Another type has a curved dish and a reflector. This type is called a reflecting telescope. th e antenna is mounted above the centre of the dish. radio waves strike the dish and reflect back to the antenna. the radio waves cause an electric current in the antenna. The current refereed o as a Signal is then amplified by the receiver. A computer processes the signal and produce and Image astronomers can study. The entire telescope is mounted on a movable support so that its direction can be changed to point to any point in the sky.
Some Radio telescope are in form of “bowls” carved in the Earth and lined with metal.These ones cannot be aimed at different point in the sky instead they detect signals from sources that pass overhead. One radio telescope of this type is the 305-m dish at Arecibo, Puerto Rico.
Rockets, satellites and other spacecraft are used to carry instrument to space Theses instruments are used to detect and measure radiation from outer space. they have an advantage of not being disturbed by the atmosphere since they are in space. This is because the atmosphere filter out some radiation from entering into Earth and example is X-ray, only a fraction enters Earth. Using satellites to detect X-rays has led to discovery of new stars. Gamma radiation detection also enable astronomers to explore the farthest reaches of space. A major outer atmosphere telescope is the Hubble.