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Figure 3B. Secondary mirror centered
under focuser tube, viewed through the
Collimating Eyepiece (as are the next
two illustrations).
Figure 3C. Secondary mirror correctly
aligned (tilted).
Figure 3A. The view down the focuser tube of a Newtonian reflector with eyepiece removed. In this
example, the optical system is badly out of collimation.
Figure 3D. Primary mirror correctly
aligned. The telescope’s optical system
is now collimated.
