Why do the hardness ratios differ from table to table in the SASS output?

(5/14/92)

The hardness ratios are calculated at various steps in the SASS processing. The hardness ratios present in the file *_hrd.asc arise from integrating the source spectrum, but WITHOUT a vignetting correction. These ratios are believed to be somewhat unreliable. The hardness ratios present in the files *_mas.asc and *_dsa.asc should agree. Both arise from the maximum likelihood detection algorithm, and should be relatively trustworthy. The flux and significance are found in each band, and each photon is weighted by a gaussian approximation to the PSF.

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