The filters available for PHT-P and PHT-C are listed in
Tab 1 and 3. Let R
be the
actual bandpass,
which is the filter transmission function convolved with the relative
spectral detector
response
,
the central wavelength 
, filter width
, and the average relative system response R
are defined as:
is the width of a rectangular filter having the same
integrated relative system response as the actual bandpass. The relative response curves
of all bandpasses together with the equivalent rectangular bandpasses are
shown in Appendix C. Note that due to the large wings of
especially the long wavelength filters, the rectangular width
is significantly different from the full width at half maximum.
Some useful filter combinations are illustrated in Fig. 7.