A demonstration of the partial-sky correction for the jackknife pseudo-C_ℓ. In the top-left panel, the angular correlation function for the Euclid DR1-like mask (black) is compared to that of a single jackknife sample mask (blue). For angular scales between approximately 80° and 100°, no baselines are present in the footprint or the mask correlation function; this region is dominated by numerical noise. Since the jackknife footprint is slightly smaller, its mask correlation function contains fewer baselines in this range. In the bottom-left panel, we show the partial-sky correction function as the ratio of the full footprint to the jackknife footprint correlation functions (blue). The difference in baselines leads to significant noise in this correction function. This noise is mitigated by applying a logistic damping function (shown in orange). On the right, we illustrate the effect of applying a partial-sky correction directly to the jackknife C_ℓ (blue), and compare it to a correction using the logistic damping function (orange). While a direct correction results in a very noisy angular power spectrum, the damped partial-sky correction yields a more robust and reliable estimate of the C_ℓ.