Relative amount of differential chromatic refraction (left scale; solid colored curves) as a function of wavelength for different zenith angles, and the expected ﹩{\lambda }^{-2/5}﹩ dependence (right scale; solid black curve) of the second-moment squared radius ﹩{r}_{\mathrm{PSF}}^{2}﹩ for atmospheric seeing, defined in Equation (7). For each zenith angle, the refraction is set to an arbitrary value of 0 at a wavelength of 700 nm; ﹩{r}_{\mathrm{PSF}}^{2}﹩ is measured relative to that at 700 nm. The total response function at an airmass of 1.2 for each of the six LSST passbands is overlaid in color.