RADIO ASTRONOMY
detects radiation of millimetre to decametre wavelength. The receivers are similar to those used in radio broadcast transmission but much more sensitive. See also Radio telescopes.
(Figures 17-19) and (Video 1)
Figure 18
Figure 19: The view of the Planck Space Telescope on the whole sky. Planck is a European Space Agency mission, with significant participation from NASA. This image is derived from data collected by Planck during its first all-sky survey, and covers about 12 months of observations. This image of the microwave sky was synthesized using data spanning the range of light frequencies detected by Planck. These low frequencies, which cannot be seen with the human eye, cover the range of 30 to 857 gigahertz.