declination: Declination
In insol: Solar Radiation

Description Usage Arguments Value Author(s) References Examples

Computes the declination of the Sun for a given Julian Day.

1	declination(jd)

`jd`	Julian Day.

Declination in degrees and decimal fraction.

Javier G. Corripio

https://www.esrl.noaa.gov/gmd/grad/solcalc/calcdetails.html

Meeus, J. 1999. Astronomical Algorithms. Willmann-Bell, Richmond, Virginia, USA.

Reda, I. and Andreas, A. 2003. Solar Position Algorithm for Solar Radiation Applications. 55 pp.; NREL Report No. TP-560-34302, Revised January 2008. https://www.nrel.gov/docs/fy08osti/34302.pdf

declination(JDymd(2019,1,1))

jdays = JD(ISOdate(2019,1:12,21))
declination(jdays)

## Plot daily changes in declination from 2018 to 2020
jdays=JD(seq(ISOdate(2018,1,1),ISOdate(2020,12,31),by='day'))
plot(declination(jdays),xlab='days from 2018-01-01',ylab='declination')