Plots in the top panel are normalized blue wing, red wing, and blue + red wing values that have been computed after removing spacecraft-Sun distance variation and shifting the observed spectra to a common wavelength scale to account for Doppler effects. The bottom panel compares values of the MgII_EXIS index before and after spectral shifting (black and blue, respectively). Shifting to a common wavelength scale largely, but not completely, removes a ±0.1% velocity dependent bias from the index. Solid curves are 30-minute averages of the raw spectra that have a 3-second integration periods.