The mangin mirror and its primary aberrations.

Analytical expressions have been developed for the primary aberrations of the thin Mangin mirror. The surface contributions for spherical aberration, coma, astigmatism, and field curvature are stated, including the first-order transverse axial chromatic aberration. Even though the Mangin mirror is used mostly with a large relative aperture, where higher order aberrations and residual spherical zonal aberration may have to be considered, the third-order expressions will still provide a good approximation of the image quality. This is especially true when the angular field coverage is modest, and the spectral bandpass of interest is narrow. It has been demonstrated that the Mangin mirror rates very favorably when compared against other single optical elements.