Computes the Sun’s true bearing (azimuth from North, clockwise) at apparent sunset for a given latitude and month/day. Uses the standard apparent-sunset threshold h₀ = −0.833° (refraction + solar radius). No elevation/dip correction is applied.
N (non-leap), declination: δ ≈ −23.44° · cos(360°·(N+10)/365)h₀ = −0.833°cos H₀ = (sin h₀ − sin φ · sin δ) / (cos φ · cos δ)sin A = (cos δ · sin H₀)/cos h₀, cos A = (sin δ − sin φ · sin h₀)/(cos φ · cos h₀), A = atan2(sinA, cosA) → bearing in [0°,360°)