Calculation of Solar Declination,Equation of Time,Solar elevation and Solar azimuth.

Keyword

Latitude,Longitude,Principal Meridian,Number of days elapsed,Solar Declination,Equation of Time,Solar hour angle,Solar elevation,Solar azimuth.

Reference

・『建築設計資料集成 環境1』(日本建築学会・丸善株式会社).
・『建築気候』(斎藤平蔵・共立出版株式会社).
・『有害紫外線モニタリングネットワーク活動報告』(独立行政法人国立環境研究所).

Remarks

・θ0=2*π*Number of days elapsed/365(or 366)
・Solar Declination(δ) Approximation Formula:
δ=0.006918-0.399912*cos(θ0)+0.070257*sin(θ0)-0.006758cos*(2*θ0)+0.000907*sin(2*θ0)-0.002697*cos(3*θ0)+0.001480*sin(3*θ0).

・Equation of Time(Eq) Approximation Formula:
Eq=60*12*{0.000075+0.001868*cos(θ0)-0.032077*sin(θ0)-0.014615*cos(2*θ0)-0.040849*sin(2*θ0)}/π.

・Solar Elevation(α) Formula:
α=arcsin{sin(φ)*sin(δ)+cos(φ)*cos(δ)*cos(h)}.

・Solar azimuth(β) Formula:
β=arctan[cos(φ)*cos(δ)*sin(h)/{sin(φ)*sin(α)-sin(δ)}].

History

・2014/08/07:layout change.
・2009/10/05:Correction about Remarks.The braces({,}) are added to the Solar Elevation Formula.
・2009/03/23:Moved from www.am-consulting.co.jp to here and brushed up.