Before going through the list of what a bandpass can do, it's probably worth a sentence or two explaining what physical concept the Bandpass class is modeling.  Namely the transmission fraction of the incident light that makes it through either from the original galaxy or star onto the detector, or possibly just some portion of that full path.  The full path might be built up by multiplying the transmissions from different portions of the path, such as the atmosphere, telescope filters, CCD quantum efficiency, etc.  Feel free to crib from that or reword as you see fit.