1. What is the Earth Curve Calculation?

The Earth curve calculation determines how much an object drops below the horizon due to Earth's curvature. This is essential for navigation, surveying, and understanding long-distance visibility.

2. How Does the Calculator Work?

The calculator uses the geometric formula:

Where:

• \( R \) — Earth's radius (typically 3959 miles)
• \( d \) — Distance along the Earth's surface (miles)

Refraction Adjustment: Atmospheric refraction bends light, making objects appear higher than they actually are. We apply a refraction factor (typically 0.13) to account for this effect.

3. Importance of Refraction Adjustment

Details: Without accounting for refraction, calculations would overestimate the actual drop. Refraction can vary based on atmospheric conditions but is typically around 13% of the geometric drop.

4. Using the Calculator

Tips: Enter Earth's radius (standard is 3959 miles), distance in miles, and refraction factor (default 0.13). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is Earth's radius set to 3959 miles by default?
A: This is the mean radius of Earth at sea level, providing a good approximation for most calculations.

Q2: How does refraction affect the calculation?
A: Refraction bends light upward, making objects appear about 13% higher than they would without atmospheric effects.

Q3: When should I adjust the refraction factor?
A: In extreme atmospheric conditions (temperature inversions, mirages), you may need to adjust the factor. For standard conditions, 0.13 is appropriate.

Q4: Can this calculator be used for other planets?
A: Yes, simply change the radius value to match the planet you're calculating for.

Q5: How accurate is this calculation?
A: Very accurate for most practical purposes. The formula is derived from basic geometry and accounts for the primary atmospheric effect.