Question: I have a fairly complex system. Is there a quick way to see where the most significant aberrations are being introduced, or which surfaces may be most sensitive to tolerances?

Answer: Yes there is. The Siedel Diagram, sometimes called a Pagel (or Pegel) Diagram, gives a graphical representation of the third-order aberrations in a system.

Imagine you are designing a fairly complex system like a 'double-bump' microlithography lens:

Maybe you still need to improve the design, and you're thinking about adding an asphere or an extra element. Where should it go? Or maybe you're thinking about tolerancing: which surfaces are likely to be most sensitive?

A good place to start in answering these questions is the Seidel Diagram, found under Analysis -> Aberration Coefficients -> Seidel Diagram:

The Seidel Diagram shows the five third-order Seidel aberration coefficients as a histogram for each surface, and as a system sum. It helps to identify easily those surfaces that add or subtract most of a certain aberrations, and also which surfaces are balancing aberrations. Its a quick way to zoom into the hardest-working surfaces in your system!