a.b.
Figure
Figure 20. gently push the telescope horizontally to determine direction of optical axis offset.
Note: This calibration method can be applied to both refract- ing and reflecting telescope designs. Differences in the optical path of telescopes do not affect how the telescope tube and tube rings should be adjusted on the mounting plate.
Figure 21a. Adjust the optical axis offset screws this way if Polaris moves toward the center of the eyepiece when the tube is pushed as in Figure 19.
Figure 21b. Adjust the screws this way if Polaris moves away from the center of the eyepiece.
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