Radio Astronomy at Long Wavelengths

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 119.

The spectacular success of Earth-based radio astronomy is due to several factors. A broad atmospheric window of more than four orders-of-magnitude in frequency extends from ~30 MHz (wavelength 10 m), where ionospheric distortions and opacity begin to become a problem, to ~300 GHz (wavelength 1 mm), where atmospheric absorption becomes excessive, even from high mountain sites. This radio window reveals a rich variety of astrophysical phenomena. Also key to the success of radio astronomy has been the development of interferometry which provides high resolution, even at long wavelengths, without the construction of impossibly large and expensive single dish radio telescopes.