Free online tool
Get coordinate-based solar times with polar-day and polar-night detection.
Use east-positive longitude and the actual standard or daylight-saving UTC offset for the selected location and date.
Method
Stopwatch elapsed time uses a monotonic high-resolution browser clock. Calendar results use Gregorian and ISO rules, while lunar and solar results apply documented mean-cycle and coordinate formulas.
Astronomical output is an estimate. Coordinates, elevation, refraction, local terrain, the entered UTC offset, and the simplified lunar model can change observed or high-precision event times.
Questions
The calculation uses the common official zenith of 90.833 degrees, accounting approximately for atmospheric refraction and the solar disk radius.
Elevation, terrain, atmospheric conditions, refraction models, coordinate precision, and time-zone or daylight-saving input can shift observed times.
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