Which limitation affected astrolabe accuracy when measuring star altitudes near the horizon?

💡 Explanation

When observing stars near the horizon, atmospheric refraction occurs because the bending of light rays passing through the atmosphere increases significantly, causing stars to appear higher than their actual position. Therefore angular distortion increases, rather than parallax, flexure, or magnetic errors that are less prominent at these conditions.

• Which cumulative failure mode impacted long-term stability of Roman roads built on clay-rich soil?
• During winter, which outcome reduces the structural integrity of a Roman aqueduct's arched keystone?
• Which outcome occurs when a Roman aqueduct experiences differential ground settlement?
• Which risk increased during the Roman Empire’s road construction throughout conquered territories?
• Which structural failure mode limited the height of early suspension bridges before the 19th century?
• Which outcome resulted from over-tempering bloomery steel in medieval sword smithing?