 
 
 
 
 
 
 
  

 IRAM, 300
rue de la Piscine, F-38406 Saint Martin d'Hères,
France
 IRAM, 300
rue de la Piscine, F-38406 Saint Martin d'Hères,
France LAOG, BP53, F-38041 Grenoble Cedex 9, France
 LAOG, BP53, F-38041 Grenoble Cedex 9, France
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Calibration compensates for imperfections and unknowns in the instrument use, including antenna defects (surface quality, focus), pointing errors, atmospheric transmission and fluctuations, receiver and backend gain and instabilities, etc...All of them are varying in time. In addition, calibrated data are also expressed in a reliable physical unit.
This lecture is then cut in three parts, of equal importance: