The wavelength range of the near-infrared section of the infrared spectrum goes from 0.7 microns to 5 microns. At this wavelength, astronomers see cooler red stars, such as red giants and red dwarfs. Space dust also becomes more transparent.
The mid-infrared spectral region ranges from 5 microns to 40 microns. Planets, comets and asteroids come into view in the mid-infrared spectrum. The light seen is the light from the temperature given off by these objects, not light reflect by a star as seen in the visible spectrum.
The far-infrared spectrum rounds out the infrared spectrum, ranging from 25 to 40 microns up to 300 microns. Astronomers no longer see stars at this part of the infrared spectrum. Mostly cold molecular clouds, dust and distant galaxies are seen at this wavelength. Astronomers also see proto-stars forming at this wavelength.