Appendix: NICMOS testing ======================== :Author: Elizabeth Barker The NICMOS certification of Pysynphot found three types of significant differences between Pysynphot and SYNPHOT calculations: 1. Better wavelength sampling in Pysynphot - This produced notable differences in regions of steep spectral gradients and narrow emission lines. Differences of ~3% were not uncommon in a few points of spectra using the obsmode "nicmos,3,g206". 2. Different spectral endpoint handling - The extrema of spectra can be significantly different between SYNPHOT's and Pysynphot's handling of them. When comparing results, users would be advised to ignore differences in the first two and the last two endpoints. 3. Extended integration range in Pysynphot - The integration of composite spectra is potentially affected over long wavelength ranges. When users compare previous results from SYNPHOT with current Pysynphot results, they should be aware of how these issues will affect their calculations.