Question 798Navigation General

The correct answer is C) Centering error. A centering error is a nonadjustable error of the sextant, meaning it cannot be corrected or eliminated through adjustment of the sextant. This error occurs when the center of the index mirror or the horizon mirror is not perfectly aligned with the axis of the sextant. This misalignment can cause a constant angular error in the sextant's measurements, which cannot be compensated for through calibration or adjustments. The other options are incorrect because they represent different types of sextant errors that can be adjusted or corrected. Error of collimation (A) can be adjusted by aligning the index mirror and the horizon mirror, side error (B) can be corrected by adjusting the index mirror, and error of perpendicularity (D) can be minimized by ensuring the index mirror is perpendicular to the frame of the sextant.