| About ROSAT |
ROSAT Home Page | ROSAT Images |
|---|
The WFC focal plane detector has no intrinsic spectral capability.
Nevertheless the WFC can be used
to measure XUV `colours' with a set of observations through different filters,
and thus place constraints on source spectra. The WFC filters have been designed
to define as set of relatively narrow passbands giving good sensitivity to a
wide range of spectra (see Figure 5.2 
and
Table 5.3 ).
The sensitivity of the WFC for filter spectroscopy can be evaluated
using the predicted count rates given in Figures 12.3 - 12.7
. To illustrate the
ability of the WFC to make such measurements in a more convenient form,
Figure 12.8 shows some examples of the filter count rate
ratios predicted as a function of spectral
parameters for two selected filter pairs. The spectral sensitivity
is clearly a strong function of the filter combinations used.