(A) Instrumental broadening for 26 HgNe arc lines (filled circles), here for representation purposes obtained by stacking the spectra along columns in (B). The data points and the ID of the column that produced them have the same color-coding. The colored solid lines are a sixth order polynomial fit, used to interpolate the resolving power at the desired wavelength. (B): An example resolving power map close to Hα. The x-axis shows the column ID, color-coded as in (A).