Hi all; I am a new user to ENVI. My job involves working with data from a pair of  airborne hyperspectral imagers that were used to image clouds during a science field campaign. The first thing that I need to do is to obtain the spectral response function of the 2.21 micron channel of the imager using the aquired data.  However, I can't find in the ENVI literature a straight forward way to do that. I'd need both a plot and a table for a range wavelenghts around 2.21 microns. Does anyboy have an idea of how to do this? Thanks in advance for your input,   Lorenzo.