Which error arises when a 18th-century navigator uses a sextant without correcting for index error?

💡 Explanation

When a sextant's mirrors are not perfectly parallel at zero degrees, index error is present because the apparent altitude of a celestial body is shifted. This causes systematic error in altitude readings. Therefore, the altitude is typically underestimated, rather than introducing longitude or declination errors, which stem from other sources.

• Which mechanical failure was prevalent in early Mesopotamian bronze agricultural plowshares during abrasive soil tilling?
• Which optical phenomenon enabled Ibn al-Haytham's precise determination of star distances using parallax?
• Which limitation arose when medieval Islamic astronomers empirically adjusted astrolabe scales to refine celestial measurements?
• Which primary risk increased in early steam engines due to the use of cast iron boilers?
• Which optical outcome occurred when medieval Islamic scholars polished lenses with progressively finer abrasives?
• Which mechanism causes the iterative solutions in Al-Khwarizmi's algebra to converge to numerical approximations?