pvlib.solarposition.declination_cooper69#

pvlib.solarposition.declination_cooper69(dayofyear)[source]#

Solar declination from Duffie & Beckman and attributed to Cooper (1969).

See [1] for details.

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).

References