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What a Radio Telescope can Measure

A radio telescope can be used to measure the following:

The radio window

Amount of transmission through the earth's atmosphere as a function of wavelength.

The above figure shows the amount of transmission through the earth's atmosphere as a function of wavelength. Clear areas mean the atmosphere is transparent. Shaded areas mean no radiation gets through the atmosphere at those wavelengths. There are two prominent windows through which to make earth based observations, the optical and radio windows with the radio window covering a much larger wavelength band than the optical. The window's width varies slightly depending upon atmospheric conditions but is generally from 1 cm to 10 m. Wavelengths greater than 10 m are reflected by the ionosphere, the amount of reflection being a function of the electron density. The short wavelength limit is due to atmospheric absorption and depends on atmospheric composition such as the presence of cloud cover.