pysynphot.obsbandpass: The ObsBandpass user interface needs to support either the usual
(acs,hrc,f555w) obsmode style that produce a set of chained
throughput files; or something like (johnson,v) that has a single
throughput file.
pysynphot.units: Units class hierarchy: is used to manage both wavelength and flux
unit conversions
pysynphot.wavetable: This module handles the wavecat.dat table presently used by the
synphot countrate task (and thus the ETC) to select an appropriate
wavelength set for a given obsmode.