Although the approach using Fermat's Principle shows the origin of seeing
effects, the statistical processes that lead to the effects described make it
impractical to proceed further with this approach. Selected results based on a
statistical approach to atmospheric turbulence are given in Chapter 16.
3.7. CONCLUDING REMARKS
3.7.a.
RAYS AND WAVEFRONTS
The application of Fermat's Principle to find conic surfaces that are perfect
mirrors makes use of
rays
and optical path lengths. A different way of looking at
what a focusing system does is in terms of wavefronts. A wavefront is simply a
surface on which every poin
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