  We present a method based on Mueller calculus to calibrate linear
polarimetric observations. The key advantages of the proposed way of
calibration are: (1) that it can be implemented in a data reduction pipeline,
(2) that it is possible to do accurate polarimetry also for
telescopes/instruments with polarimetric non-friendly architecture (e.g.
Nasmyth instruments) and (3) that the proposed strategy is much less time
consuming than standard calibration procedures. The telescope/instrument will
polarimetrically be described by a train of Mueller matrices. The components of
these matrices are dependent on wavelength, incident angle of the incoming
light and surface properties.
