The following graphs and tables are to be used for proposal planning. They should be used with caution for data analysis. Using the appropriate graph, the HRC (S or I) count rate can be estimated from the incident (unabsorbed) X-ray energy flux density F_x,unab. Four source spectral models have been used: power law, blackbody, thermal bremmstrahlung, and Raymond-Smith (from XSPEC, v10.0) thermal spectrum. For HRC-S, only the central "T" region of the detector is considered here.

The energy interval used to calculate the energy flux densities and rates were 0.07 - 10.0 keV.

The unabsorbed energy flux density is that energy flux density which would measured at the telescope aperture if there were no interstellar material present (0 hydrogen column density). It is used when the source luminosity L_x and distance R are known.

F_x,unab = L_x/4piR²

The count rate CR is given by

CR = F_x,unab x ECF

ECF is given by

The HRC effective area is given by

for HRC-I

for HRC-S (central T)

The ECF graphs and tables are normalized to an incident flux density of 10^-10 erg cm² s^-1.