pvlib.solarposition.declination_cooper69¶
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pvlib.solarposition.
declination_cooper69
(dayofyear)[source]¶ Solar declination from Duffie & Beckman [1] and attributed to Cooper (1969)
Warning
Return units are radians, not degrees.
Declination can be expressed using either sine or cosine:
\[\delta = 23.45 \sin \left( \frac{2 \pi}{365} \left(n_{day} + 284 \right) \right) = -23.45 \cos \left( \frac{2 \pi}{365} \left(n_{day} + 10 \right) \right)\]Parameters: - dayofyear : numeric
Returns: - declination (radians) : numeric
Angular position of the sun at solar noon relative to the plane of the equator, approximately between +/-23.45 (degrees).
See also
References
[1] J. A. Duffie and W. A. Beckman, “Solar Engineering of Thermal Processes, 3rd Edition” pp. 13-14, J. Wiley and Sons, New York (2006)
[2] J. H. Seinfeld and S. N. Pandis, “Atmospheric Chemistry and Physics” p. 129, J. Wiley (1998)
[3] Daryl R. Myers, “Solar Radiation: Practical Modeling for Renewable Energy Applications”, p. 4 CRC Press (2013)