Classes and methods to get solar radiation angle of incidence on a surface. Based on the NREL report "Solar Position Algorithm for Solar Radiation Applications" by Ibrahim Reda and Afshin Andreas.
https://www.nrel.gov/docs/fy08osti/34302.pdf
See the documentation folder for a copy of this report.
Example:
example_inc_angle.py will plot the incidence angle on a surface of given orientation as a function of time.