Design of Mirror and Catadioptric Systems

1. It has both coma and astigmatism if the stop not at focus.

2. For distant objects -> undercorrected spherical aberration

3. object located at one focal point of a conic --> the image located at the other focal point, no spherical aberration

4. aperture located at the plane of a focus -> image is free of astigmatism

5. Reflecting Systems

5.1. need increase because the difficulty to find satisfactory refractive materials for non visible spectrum

6. Spherical Mirror

6.1. The aberration is only one-eighth of that of an equivalent glass lens

6.2. If the stop at its center of curvature the image is free of coma and astigmatism

7. Paraboloid Reflector

7.1. generated by rotation of the conic sections circle

7.2. object imaged at the focus without spherical aberration

8. Ellipsoid and Hyperboloid

8.1. arranged to correct coma, astigmatism and spherical

8.2. negative lens near the secondary to correct the coma.

8.3. doublet near focus to correct the astigmatism and Petzval

9. Conic Section

9.1. aperture located in the plane of a focal point --> no astigmatism

10. Schmidt System

10.1. consists of a spherical reflector with an aspheric corrector plate at its center of curvature

10.2. spherical aberration corrected by the corrector plate

10.3. higher-order forms of astigmatism.

11. Mangin Mirror

11.1. combined reflecting and refracting

11.2. consist of two surfaces spherical mirrors

11.3. the first surface chosen to correct the spherical aberration

11.4. one radius is chosen arbitrarily

11.5. other radius is varied systematically until the spherical aberration is corrected

12. Maksutov System

12.1. extension of the Mangin mirror principle

12.2. correcting lens is separated from the mirror

12.3. combined with a Schmidt-type aspheric corrector plate to correct chromatic