Which measurement error increases in a sextant if its mirrors are not perfectly perpendicular to its frame?

💡 Explanation

When the sextant mirrors aren't perpendicular, index error occurs because this misalignment introduces a systematic offset in angle readings, particularly noticeable when zeroing the instrument. Therefore, angular measurement error results, rather than parallax, refraction, or aberration, which are related to observational conditions.

• Which outcome accelerated soil degradation in some pre-Columbian Andean terrace farming systems?
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• Which action enabled Mesopotamian bronze smiths to achieve superior hardness in their cast tools and weapons?
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