This animation shows how light energy is collected by the optics system on the Atmospheric Infrared Sounder (AIRS) instrument and digitized.
Energy from the scene is directed by the scan mirror into the AIRS telescope. The telescope collects the Earth scene energy and defines the instantaneous field of view (the 1.1 degree spot on the ground as opposed to the +/- 50 degree earth scan field of view). Filters located at the entrance to the spectrometer separate the energy into 11 different spectral ranges. Optical elements direct this energy to a grating which disperses the energy into a continuum of frequencies. The detector elements then collect discrete spectralranges of (i.e. frequencies) of energy which define the 2378 AIRS infrared spectral channels. The signals from the detectors are digitized, formatted, etc. and transmitted to the spacecraft which broadcast the data to the ground.