Which limitation affected sextant accuracy when measuring celestial bodies from a rolling 18th-century ship?

💡 Explanation

When using a sextant on a rolling ship, horizon instability occurs because the visible horizon line constantly shifts, leading to inaccurate altitude measurements. Therefore, aligning the sextant is difficult, rather than lens distortion, refraction, or index error which depend little on ship's motion.

• Which issue arises when inadequate drainage exists alongside a Roman road built on clay-rich soil?
• Which outcome manifested when sections of the Roman Appian Way experienced differential settling on heterogeneous ground?
• Which adjustment was necessary when using a brass astrolabe across varying ambient temperatures for astronomical observations?
• Which outcome occurred when ancient Mesopotamian bronze metalworking reached temperatures above 1085°C in crucible furnaces?
• Which mechanical consequence resulted from the development of accurate chronometers for navigation in the 18th century?
• Which stability risk increased during the construction of Roman roads across marshy terrain?