Which navigational error increases when a 1760s-era sextant's index mirror shifts during high seas?

💡 Explanation

When a sextant's index mirror shifts under rough conditions, the accurate alignment between the horizon and celestial body gets compromised, leading to parallax error and incorrect altitude measurements. Therefore altitude errors result, rather than longitude errors, heading errors, or latitude calculation errors, because those stem from different sources during celestial navigation.

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