Comparison of the rectified synthetic spectrum of W239 (red line) to observations (black line), acounting for the WC9 line dilution from the unseen companion and warm dust. Spectra were obtained in 2001 June (1.5 m/B&C), 2005 June (NTT/SofI) and 2008 July (VLT/FLAMES). Note the two emission features shortwards of 6500 Å are the result of incomplete sky subtraction; telluric contamination is also manifest in the observed spectrum beween  ~ 7200–7400 Å, 1.35–1.50 μm and 1.77–1.8 μm.