Day Length From Latitude
Calculator

Inputs

Sunrise/sunset hour angle (degrees)
115.694193

Results

Sunrise/sunset hour angle (degrees)
115.694193
Daylight duration (hours)
15.425892
Night duration (hours)
8.574107

Astronomy results

Sunrise/sunset hour angle (degrees)115.694193
Daylight duration (hours)15.425892
Night duration (hours)8.574107

formula-map diagram

Sunrise/sunset hour angle (degrees)
115.694193
Daylight duration (hours)
15.425892
Night duration (hours)
8.574107

Astronomical relationship

Formula

H₀ = arccos(−tan(lat)·tan(decl)); daylight (h) = 2H₀ / 15°

= 115.69419309892

Note

This result is a simplified model: it applies the displayed textbook formula to the values you entered, assuming ideal spherical bodies, circular orbits, blackbody radiation and perfect optics, and ignoring atmospheric seeing, relativistic corrections beyond those stated, cosmological models and measurement uncertainty. Use published ephemerides and catalogue data for real observations.

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