1. What is a Length Of Day Calculator?

Definition: This calculator estimates the duration of daylight hours based on latitude and solar declination.

Purpose: It helps astronomers, meteorologists, and outdoor planners determine daylight duration at specific locations and dates.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Hours \) — Duration of daylight (hours)
• \( \phi \) — Latitude (degrees, -90 to 90)
• \( \delta \) — Solar declination (degrees, -23.45 to 23.45)

Explanation: The formula calculates the hour angle when the sun rises/sets, then converts this to daylight duration.

3. Importance of Day Length Calculation

Details: Knowing day length helps in agriculture, solar energy planning, outdoor activities, and understanding seasonal variations.

4. Using the Calculator

Tips: Enter latitude (-90 to 90°) and solar declination (-23.45° to 23.45°). Values outside these ranges will not compute.

5. Frequently Asked Questions (FAQ)

Q1: What is solar declination?
A: The angle between the sun's rays and Earth's equatorial plane, varying between ±23.45° throughout the year.

Q2: How do I find solar declination for a date?
A: Use declination tables or formulas based on the day of year (e.g., ~23.45° at summer solstice, 0° at equinoxes).

Q3: Why does the formula give 24 hours at polar day?
A: When the sun doesn't set (arccos argument < -1), the calculator will show maximum daylight duration.

Q4: Does this account for atmospheric refraction?
A: No, this is a theoretical calculation. Actual daylight is slightly longer due to atmospheric effects.

Q5: How accurate is this calculation?
A: It's mathematically precise for the simplified model, but real-world conditions may cause slight variations.