Next: Model Spectra for Spectral-Fitting Up: Spectral Analysis Previous: A Quick Look at . ... For ROSAT PSPC data, this conversion is done during the on-line (SASS) processing. For IPC observations, the instrument gain varies both across the detector and in time, and is applied during off-line processing (PROS) using the BAL histogram. By default, spectra are extracted in PI bins for PSPC data and in PHA bins for IPC data. ... Special techniques are required when using Einstein IPC data. ...