  A telescope polarization model for the SST [Swedish 1-m Solar Telescope] is
developed and the parameters of this model are fitted to polarization
measurements made with a 1-meter linear polarizer in front of the entrance
window. In this model, the 1-meter lens is characterized by a five-parameter
Muller matrix, corresponding to a retarder with arbritary variations of the
retardance and fast-axis orientation across the aperture. The resulting model
is verified by measuring the telescope polarization for unpolarized input light
and comparing to predictions from the polarization model. The accuracy of the
prediction is within approximately 0.4% for all normalized polarization
components (Q/I, U/I and V/I).
  The polarimeter used is based on two nematic liquid crystals and one linear
polarizer, and will be used for both imaging polarimetry and
spectropolarimetry. The most critical calibration is measuring the modulation
matrix. This is done by inserting one linear polarizer and one rotating
quarter-wave plate in the optical path before the polarimeter, and measuring
the modulated intensity. The calibration of the quarter-wave plate is optimized
by measuring the linear polarizer only with the polarimeter, and then
minimizing the error in degree of polarization plus the residual error for the
inversion of the modulation matrix by iteration of the two unknown parameters
(retardance and angle offset). We find that small non-linearities in the CCD
response is the major obstacle in calibrating the polarimeter. The first full
Stokes imaging polarimetry observations at the SST are shown. Comparing images
before and after telescope compensation verify the telescope polarization
model.
