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Daylight Hours Formula:
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The Daylight Hours calculation estimates the number of hours of daylight at a specific location on Earth for a given day of the year. It uses astronomical formulas based on latitude and solar declination to determine sunrise and sunset times.
The calculator uses the astronomical formula:
Where:
Explanation: The formula calculates the hour angle of sunrise/sunset and converts it to daylight duration. The result represents the time between sunrise and sunset.
Details: Calculating daylight hours is essential for agriculture, solar energy planning, outdoor activities, architectural design, and understanding seasonal variations in different geographical locations.
Tips: Enter latitude in degrees (-90 to 90) and solar declination in degrees (-23.5 to 23.5). The calculator automatically converts degrees to radians and computes the daylight duration.
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. It varies throughout the year between approximately -23.5° and +23.5°.
Q2: Why does daylight duration vary?
A: Daylight duration varies due to the Earth's axial tilt (23.5°) and its orbit around the sun, causing seasonal changes in the angle and duration of sunlight.
Q3: What are extreme cases of daylight hours?
A: At the equator, daylight is nearly constant at 12 hours. At the poles, there can be 24 hours of daylight (midnight sun) or 24 hours of darkness during solstices.
Q4: How accurate is this calculation?
A: This provides a theoretical maximum. Actual daylight can be affected by atmospheric refraction, terrain, and local weather conditions.
Q5: Can this calculate for any date?
A: Yes, when provided with the correct solar declination for that specific date. Declination can be calculated or looked up in astronomical tables.