Example PSFs at 500 nm for the off-axis aperture (left panels) and on-axis aperture (right panels) baseline HWO apertures shown in Figure 8. The core throughput region of radius 0.7λ/D is shown by a red dashed circle, and the effective diameter D depends on the aperture area. Within the IWA, the PSF is not centered; see C. Aime et al. (2024) for similar results for the 26 m NGRST rendezvous starshade. In our analysis of core throughput, we center the photometric aperture on the calculated centroid of the PSF using the position that maximizes the cross-correlation with a Gaussian template of the same aperture resolution.