To make the polarization map of a field, the three
polarizers 120 degrees apart, and the free hole of the entrance
wheel are used with the same number of exposures 
for each.
For each configuration of the camera (Channel, PFOV, filter or CVF
, 
), the system takes first
exposures on the free hole. Then it does 
cycles of
measurements on the polarizers. A cycle consists of a set of three
images, one on each polarizer, with 12 exposures per image.
must be 
4. Splitting the observation in a
number of cycles performs a `polarization modulation' which may
be beneficial if is large in order to discriminate
polarization effects from long term drifts.
If required is 
48, then is
forced to 48, and = 4.
If required is > 48, then =
int(
), and is set to
12
Beam-switching, CVF scan, raster scan and FLASH-MODE SW observations are not supported in polarized observations.
The total observation time is:
which are
described in sections 
, and
.