Comparison of the 1σ uncertainties of the estimated planetary SED derived from the diagonal terms of Equation (35) for the different scenarios. To ensure comparability, it is assumed here that the correct planet position is known a priori, even for the optimistic unwhitened case. Top: the black dashed line shows the true planetary spectrum, and the shaded areas indicate the uncertainties obtained from averaging over 50 simulated observations. Significant differences are seen below ∼10 μm. Bottom: the 1σ uncertainties of the optimistic whitened, optimistic unwhitened, and pessimistic whitened cases, normalized by the ideal uncertainty. Results for the pessimistic unwhitened scenario are not shown, as the algorithm was not able to converge.