Diffraction pattern and radial intensity distribution for a perfect, unobstructed parabolic mirror, supported on a Plop optimized 6-point support. Diameter = 317.5 mm (12.5 in). Focal Length = 1587.5 mm (62.5 in). f/ Number = 5. Thickness = 30.48 mm (1.2 in). Material = Pyrex 7740.



Diffraction Pattern

It is very difficult to tell this pattern from the perfect case. The peak intensity is reduced by 0.16%

Radial Distribution of Intensity

Again, it is difficult to differentiate this plot from the perfect case.
Difference between this pattern and perfect diffraction pattern.

One can make out a six lobed pattern in the second diffraction ring, but the amplitude is tiny. there is evidence of a second six lobed pattern outside the first, but it's amplitude is even less.

Radial Distribution of difference between this pattern and perfect diffraction pattern.

Light is subtracted from the Airy disc and added to a broad zone beginning at about the second diffraction minimum. The total amount of light involved is very small.