Results of the telluric correction (red) for a bad (top) and a good (bottom) case. The grey areas mark regions of extremely high telluric absorption and thus high noise in the corrected data. The lines at 1093.5 nm and 1281.4 nm are stellar lines and the variable peak at about 2100 nm is caused by variations in the flux level and spectral energy distribution of the NIR flat field lamp.