The SolarCalucuator.swift was created by Dr. Jeff Craighead and has been tested on iOS 8.3.

This code is based on the NREL Technical Report "Solar Position Algorithm for Solar Radiation Applications" which provides C source for the calculations.
NREL/TP-560-34302 - November 2005 revision
http://www.nrel.gov/docs/fy08osti/34302.pdf

I made some modifications to eliminate the use of the SPA struct and often return a tuple for methods that would modify the contents of that struct.
You really don't need to worry about any of that, there are only a handful of important methods you need to use this library. They are:

-spa_calculate:
	calculates all the various solar output parameters described in the NREL report based on the latitude, longitude, time, date, altitude, and optionally temperature and air pressure you set.

-get_sunrise_tuple:
	returns a tuple with Hour, Minute, and Second that indicates the sunrise time for the day used when spa_calculate was run

-get_sunset_tuple:
	returns a tuple with Hour, Minute, and Second that indicates the sunset time for the day used when spa_calculate was run

-get_suntransit_tuple
	returns a tuple with Hour, Minute, and Second that indicates the sun transit (solar noon) time for the day used when spa_calculate was run

-showRTSAlertView:
	on iOS displays an AlertView with the next sunrise, sunset, and sun transit for the based on the parameters you provide (latitude, longitude, altitude)