Which systematic error affected 18th-century maritime navigation when using a sextant at sea?

💡 Explanation

When mirrors are slightly misaligned an index error occurs affecting all angle measurements because the sextant's zero point shifts systematically. Therefore, the index error results, rather than parallax which is manageable using the sight, retraction error which can be factored out with the tables, or thermal, which is not pronounced enough.

• Which risk increased when early Mesopotamian irrigation systems diverted river water containing suspended soil to enhance crop yields?
• Which risk increases when a Roman aqueduct's arcade bridge is constructed with significantly undersized voussoirs at the crown?
• Which problem emerged in early 18th century wooden warships due to persistent hull wetness below the waterline?
• Which limitation restricted the use of brass astrolabes for high-precision stellar observations in medieval observatories?
• Which risk increases when ancient terrace farming systems experience intense rainfall?
• Which outcome resulted from the intentional addition of arsenic to copper during the Early Bronze Age?