Techniques
Radio astronomers use different techniques to observe objects in the radio spectrum. Instruments may simply be pointed at an energetic radio source to analyze its emission. To “image” a region of the sky in more detail, multiple overlapping scans can be recorded and pieced together in a mosaic image. The type of instrument used depends on the strength of the signal and the amount of detail needed.
Observations from the Earth's surface are limited to wavelengths that can pass through the atmosphere. At low frequencies, or long wavelengths, transmission is limited by the ionosphere, which reflects waves with frequencies less than its characteristic plasma frequency. Water vapor interferes with radio astronomy at higher frequencies, which has led to building radio observatories that conduct observations at millimeter wavelengths at very high and dry sites, in order to minimize the water vapor content in the line of sight.
Read more about this topic: Radio Astronomy
Famous quotes containing the word techniques:
“The techniques of opening conversation are universal. I knew long ago and rediscovered that the best way to attract attention, help, and conversation is to be lost. A man who seeing his mother starving to death on a path kicks her in the stomach to clear the way, will cheerfully devote several hours of his time giving wrong directions to a total stranger who claims to be lost.”
—John Steinbeck (1902–1968)
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—Neil Kurshan (20th century)