1. What Are Sunrise and Sunset Calculations?

Sunrise and sunset calculations determine the times when the upper edge of the Sun appears on the horizon. These times vary based on location (latitude) and time of year (solar declination).

2. How Does the Calculator Work?

The calculator uses these equations:

Where:

• \( DL \) — Day length in hours
• \( \phi \) — Latitude in degrees
• \( \delta \) — Solar declination in degrees
• 12 — Solar noon (time when sun is highest)

Explanation: The equations account for the Earth's tilt and the observer's latitude to calculate when the sun appears and disappears.

3. Importance of Sunrise/Sunset Times

Details: Knowing sunrise and sunset times is crucial for agriculture, photography, aviation, marine navigation, and various outdoor activities.

4. Using the Calculator

Tips: Enter latitude (-90 to 90°) and solar declination (-23.5° to 23.5°). Results show sunrise, sunset, and day length in hours.

5. Frequently Asked Questions (FAQ)

Q1: What is solar declination?
A: Solar declination is the angle between the Sun's rays and the Earth's equatorial plane, varying between ±23.5° throughout the year.

Q2: Why does day length vary?
A: Day length varies due to Earth's axial tilt (23.5°) and its orbit around the Sun, creating seasons.

Q3: How accurate are these calculations?
A: These are approximate times. Actual sunrise/sunset may differ due to atmospheric refraction, elevation, and local topography.

Q4: What about polar day/night?
A: At extreme latitudes, the equations may return invalid results (when tanφ tanδ > 1), indicating either 24-hour daylight or darkness.

Q5: Can I calculate for any date?
A: Yes, but you need the solar declination for that date, which can be calculated separately.