Since neither GMOS is equipped with an ADC, how does differential atmospheric refraction affect you, and how do you correct for it?
For example, some of my work uses low-resolution timeseries spectra, and we see the wavelength solution changing during the observation. One approach that I have used for our data is to compute a theoretical model for the expected offsets as a function of wavelength and airmass and use these to interpolate each individual spectrum onto a constant wavelength grid. We lack sufficient resolution to use the spectral lines themselves to measure wavelength offsets for most wavelengths, which is why we rely on a model.
Does differential atmospheric refraction affect you in a different way? What correction procedures do you use and why do you prefer them?