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Fig. 4


Approximation AU(h) of a constant level with help of the set of U(h). Black curves (1) show the approximation with 10 indices, gray (2) with 4 indices. For clarity the gray graphs are shifted to the level of 0.8. Thick lines correspond to the weight of  ~h, thin lines to the other power of altitude. Curve 3 corresponds to the weighting of  ~h7/5. Gray dashed 4 is the WF for the aperture A.

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