Radio Telescope Antennas of Large Aperture

Equations are derived for the number of sources which a radio telescope can detect and the number which it can resolve. Based on these relations curves for the number of sources which can be both detected and resolved, as a function of frequency and aperture, are presented. The need for large apertures in order that radio astronomy deal with significant numbers of sources is evident. It is also pointed out that there is a most economical frequency for radio astronomy in the vicinity of 300 mc. A design for a radio telescope which provides a large aperture at low cost is described. It consists of a fixed standing parabolic reflector with a tiltable flat-sheet reflector. The advantages of the design are pointed out and the results with a scale model are described.