The SPX from the 2/11/16 bottom appears to be forming an Elliott wave Ending Diagonal Triangle. Please see my prior SPX posts. Each sub wave subdivides into three waves. The final wave "5" appears to be under construction and could be truncated- meaning it won't exceed the 8/15/16 peak at 2193. Wave "a" and "c" are usually equal. The bulls-eye target is 2182. Broader target zone 2181-2185.
9/30/16 is could be the target date for the secondary peak. That day is the end of the third quarter and has a new moon. Markets occasionally turn on new or full moons.