Assertion: sextant's error | /r/HasProperty | caused
Facets:
value: by wearing of the pivot
type: CAUSE
value: by not being perpendicular
type: MANNER
Source sentences:
text: The first error, of Perpendicularity, is caused by the index mirror not being perpendicular to the plane of the instrument.
text: This error could be caused by wearing of the pivot on which the index arm moves, perhaps because the index arm is not pivoted at the exact point of the centre of curvature of the arc.
text: Centering error is caused by the index arm not pivoting at the exact center of arc curvature.