FTS k factor used to obtain an absolute wavelength calibration of the spectra recorded from 500 to 1000 nm. We use eight U standard lines from Degraffenreid & Sansonetti (2002) that have a match in our spectrum. The blue dots indicate the k_i of each line. The error bars indicate the uncertainty calculated by error propagation of the line position measurement of our lines and the standard lines. The dashed purple line indicates the weighted average of the 8 k_i.