Comments on The Sun's Position


Hey, which angle is the 'capital phi' in the azimuth equation?
I'm trying to use your equations here but I don't get the same angles for elevation/azimuth as
compared to the sun position calculator on the next page!


I am trying to use the formulas on the bottom of the page but there are 3 variables that are undefined.



the equation for the solar azimuth angle has a typo: the argument of the arccos should also include the denominator

You are correct. It is fixed.

Thank you so much for providing those formulas and the Sun Position Calculator to check our implementation.

Regarding the last formula, the azimuth actually corresponds to the actual Sun position in the morning, but is mirrored against the meridian in the afternoon.
May I suggest to insert before the formula Azimuth = arccos(...) something like:
If HRA > 0 then Azimuth = 2π - arccos(...), otherwise Azimuth = arccos(...)

Regarding the Sun Position Calculator, my browser warns me that it will not support Flash Player anymore next year.
It would be great to have this tool available using another technology!