The signal-to-noise ratio (SNR) can be still estimated with the ISOCAM
time estimator or the ISOCAM Observers Manual. For ISOCAM no
substantial changes of sensitivities are reported. This means that
SNR estimates should be still the same as calculated before launch.
However, we stress again that the SNR is not the limiting factor of the detectable degree of polarization.
For example we measure a RMS error
of the fractional polarization ( 
) of :
for a non-polarized photometric standard star having a flux of 100 ADU/s
as observered in a 2 x 2 raster with 
, 
.
This error estimate is coming by reducing C05 data without any kind of specific transient correction method and consequently should be taken as an upper limit. Having a sound drift correction model we should do better.