Lesson Two : Tools of Radio Astronomy
Radio astronomers’ tools are slightly more complicated than optical astronomers’ because of the nature of the waves being studied. All radio observations require an antenna, consisting of lengths of pipe or wire cut to specific dimensions to pick up certain frequencies of radio waves. This antenna transfers radio waves into a radio receiver, which amplifies the signal (the waves must be amplified in order for the data to be analyzed because radio waves are hard to observe at their natural amplitude). The signal is then further electronically modified so that it can be read by a computer, which typically produces a graph of radio intensity vs. frequency. This allows radio astronomers to study the radio intensity from a certain region in the sky.
Radio antennas can be made more sensitive when the radio waves are focused onto the antennas by reflective dishes. Radio dishes look very similar to satellite dishes you may have seen by people’s homes. Their purpose is to collect more radio waves and focus them at the antenna, mounted above the rounded dish. This dish works as a mirror gathering radio waves instead of visible light. These radio dishes, however, have to be much larger than optical mirrors in order to obtain images of the same resolution.