The word "mirror" is sometimes used in place of the word "reflector". In many optical telescopes, one or more mirrors reflect the light to a focal point. A concave type of curved mirror will focus the light to a point or to a focal region. A flat mirror will reflect the light to a different direction without focussing. Similarly, radio waves (energy) can be focussed by a concave type of curved metallic structure (reflector or mirror), while a flat metallic structure (reflector or mirror) will send the radio waves (energy) to a different direction without focussing.
|The photo at the left shows the flat reflector plus the control house and the searchlight.|
|The photo at the left shows the wire mesh on the flat reflector, plus a portion of the ground plane (with weeds penetrating the aluminum ground plane and climbing the flat reflector).|
The path of the radio source being observed was as follows. Assuming the source was in the southern sky and the flat reflector was set correctly to observe the source when it crossed the meridian (the north-south line in the sky), the radio energy would reflect off the flat reflector, go almost horizontally for about 500 feet (152.4 meters) from north to south across the ground plane (look for a hot spot on the photo for the ground plane), be reflected and focussed by the paraboloidal (curved) reflector back across the ground plane from south to north to the feed horns (look for a hot spot on the photo for the feed horns). The feed horns acted as funnels to collect the radio energy. That energy was converted into a very small electrical current which was amplified more than a million times by a receiver located in an underground room (called the "focus room"). The signal was processed (including being converted into digital data which was analyzed by and stored in a computer).
© 2001-2005 Ohio State University Radio Observatory & North American AstroPhysical Observatory.