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Sensitivity

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 ( tex2html_wrap_inline177 ) of :

displaymath179

for a non-polarized photometric standard star having a flux of 100 ADU/s as observered in a 2 x 2 raster with tex2html_wrap_inline181 , tex2html_wrap_inline183 .

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.




Thu Jan 16 18:15:16 MET 1997