1. What is a Hours of Daylight Calculator?

Definition: This calculator estimates the number of daylight hours at a given latitude on a specific day of the year based on solar declination.

Purpose: It helps astronomers, meteorologists, and anyone interested in daylight patterns understand how day length varies with location and season.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Daylight — Duration of daylight in hours
• φ (phi) — Latitude in degrees (-90 to 90)
• δ (delta) — Solar declination in degrees (-23.45 to 23.45)

Explanation: The formula calculates the fraction of the day that the sun is above the horizon based on the Earth's axial tilt and the observer's latitude.

3. Importance of Daylight Calculation

Details: Understanding daylight duration is crucial for agriculture, solar energy planning, architectural design, and understanding seasonal changes.

4. Using the Calculator

Tips: Enter your latitude (-90 to 90) and the solar declination (-23.45 to 23.45) for the date of interest. The calculator will compute the hours of daylight.

5. Frequently Asked Questions (FAQ)

Q1: What is solar declination?
A: Solar declination is the angle between the rays of the Sun and the plane of the Earth's equator, varying between ±23.45° throughout the year.

Q2: How do I find solar declination for a specific date?
A: Use our Solar Declination Calculator or astronomical tables. It's approximately 0° at equinoxes and ±23.45° at solstices.

Q3: What happens at extreme latitudes?
A: Near the poles, this formula accounts for midnight sun (24-hour daylight) and polar night (no daylight) when appropriate.

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

Q5: What's the daylight at the equator?
A: Approximately 12 hours year-round, as the sun rises and sets nearly perpendicular to the horizon.