Which limitation arises when using early astrolabes to measure distant star altitudes near twilight?

💡 Explanation

When measuring star altitudes near twilight, atmospheric refraction, which bends light rays, increases near the horizon and twilight sky, leading to significant distortions and positional errors in altitude measurements taken with early astrolabes. Therefore refraction error affects the readings, rather than corrosion, parallax, or weight, because these require different environments or relate to different principles.

• What risk increased in ancient Inca terrace farming when irrigation canal sedimentation obstructed water flow?
• Which outcome limited the expansion of terrace farming by Andean civilizations despite its agricultural benefits?
• Which mapping transformation causes distortions when projecting the celestial sphere using an astrolabe's stereographic projection?
• Which agricultural consequence occurred in areas using a chinampa system when prolonged drought reduced water levels?
• Which limitation affected medieval Islamic astronomical observations using open-sighting alidades?
• Which risk increases when a Roman fort's timber palisade lacks regular creosote treatment in a humid environment?