Suppression in logarithmic units (diffraction intensity at the telescope aperture ﹩\parallel {f}_{P}^{\parallel }{\parallel }^{2}﹩) is shown for the HWO 60 m starshade with 16 petals at a wavelength of 500 nm, with a spatial sampling of ΔP = 2 cm, N_P = 6000. The central dark shadow is masked by the telescope and produces the on-axis stellar PSF. The dark shadow must therefore be as large as the aperture. To maintain the dark shadow (contrast), the Fresnel number should remain constant ﹩f=\frac{{R}_{ss}^{2}}{\lambda z}\sim 10\,\unicode{x02013}\,20﹩. This can be maintained at wavelengths outside of the band by changing the lateral flight distance of the starshade z. The dark shadow is approximately the size of the starshade in diameter (60 m).