The Key Factors in Calculation
Several key pieces of data are required to calculate sunrise and sunset times accurately:
- Latitude and Longitude: The exact geographic coordinates of the location are the most critical factor.
- Date: The time of sunrise and sunset changes daily due to the Earth's axial tilt and its orbit around the Sun.
- Time Zone: The final calculation must be adjusted for the location's local time zone, including any Daylight Saving Time rules.
- Atmospheric Refraction: Calculators also account for the bending of light by the Earth's atmosphere, which makes the Sun appear on the horizon slightly before it has physically risen.
The Process
The tool uses this data in a complex formula known as the "Sunrise Equation" to determine the time of day the Sun reaches a certain angle relative to the horizon. For sunrise and sunset, this is defined as the moment the upper limb of the Sun is on the horizon.
Conclusion
A sunrise-sunset calculator automates complex astronomical math to provide practical, useful information for photographers, planners, and anyone interested in daylight hours. To find the times for your location, use our Sunrise & Sunset Calculator.