Illustration of the data analysis steps from a short wavelength range from detector 2. The y-axis depicts the slit position relative to the star, with the slit position of the companion indicated by a “b” on the right-hand axes. The greyscales were adjusted individually for each array with an IRAF-like z-scale algorithm. Top to bottom: A) the AB-combined image corrected for bad pixels; B) the spatial profiles of the star; C) the image after each row has been normalised with the rows of the spatial profile array; D) the spatial spectra (i.e. rectified for the trace); and E) the residual spatial spectra after removing stellar and telluric lines.