Fundamentals of geometrical optics
Lagrange-Helmoltz extended invariant
An optical system is composed of several diopters D1, D2, D3...
Following (13) we have, for each diopter :
Figure 31
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Consequently, for any optical system S, for any object AB of dimension y having for image in S A'B' of dimension y', and a luminous ray going from A forming and angle
with the axis, arriving as A' under the angle
, we have :
Figure 32
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