Noiseless synthetic spectra (left column) for the no-cloud (top row and light blue), thin-cloud (middle row and darker blue), and thick-cloud (bottom row and purple) configurations. Solid lines in each subplot correspond to the spectrum at phase angle α = 37°, dashed lines at α = 85°, and dotted lines at α = 123°. The error bars indicated with vertical lines correspond to the noise at S∕N = 10 injected to create the noisy spectrum at each phase angle. Right column: same synthetic spectra but normalised with respect to the value of F_p∕F_⋆(λ = 500 nm), revealing the shape changes in the spectra at different phases.