Spectral Analysis

PSPC spectra may be produced over the channel range 1-256. However the first 7 channels should be ignored in the spectral analysis of sources observed before 11th October 1991. On this date, the operating voltage of the detector was reduced in an attempt to lower the detector background. This led to the first 10 channels becoming useless and so analysis of observations post 11th October 1991 should ignore the first 10 channels.