1. What is the SDA Sunset Equation?

The SDA (Seventh-day Adventist) sunset equation calculates the local solar time of sunset based on latitude and solar declination. It's particularly useful for determining prayer times and Sabbath observance in the Adventist tradition.

2. How Does the Calculator Work?

The calculator uses the SDA sunset equation:

Where:

• \( T \) — Sunset time in hours (local solar time)
• \( lat \) — Latitude in degrees
• \( dec \) — Solar declination in degrees

Explanation: The equation calculates the hour angle of the sun at sunset and converts it to local solar time.

3. Importance of Sunset Time Calculation

Details: Accurate sunset time calculation is important for religious observances, agricultural activities, and various outdoor activities. In the SDA tradition, it marks the beginning of the Sabbath.

4. Using the Calculator

Tips: Enter latitude (-90 to 90 degrees) and solar declination (-23.5 to 23.5 degrees). The calculator will return sunset time in local solar time (24-hour format).

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 -23.5° and +23.5° throughout the year.

Q2: How accurate is this calculation?
A: This provides approximate solar time. Actual sunset may vary due to atmospheric refraction, elevation, and local topography.

Q3: How do I convert solar time to local clock time?
A: You need to account for your longitude (time zone) and the equation of time. This calculator gives solar time at the given longitude.

Q4: What about daylight saving time?
A: This calculator doesn't account for DST. You'll need to adjust the result manually if DST is in effect.

Q5: Why does the equation use 12 as the base?
A: Solar noon is defined as 12:00 local solar time, when the sun is at its highest point in the sky.