The libraries "BigNumber" and "BigNumberMath" are not available as standard Arduino libraries. Rather than requiring these libraries to be manually relocated to the Arduino "libraries" directory, just refer to them in place. Note for an Arduino project to support this file structure all sub-directory includes must be contained within a "src" sub-directory. The sub-directory limitation was introduced in 1.6.10, see arduino/Arduino#5176, and arduino/arduino-builder#148

Author: FrodgE

Mega_Sun_Harvester_Program_V01.ino

@@ -14,7 +14,7 @@
 
 #ifndef ARDUINO_UNO
 #include "SunCalculations.h"
-#include <BigNumber.h>
+#include "src/BigNumber/BigNumber.h"
 #endif
 
 #include <Wire.h>

SunCalculations.cpp

@@ -1,6 +1,6 @@
 #include "SunCalculations.h"
 #include "globals.h"
-#include <BigNumberMath.h>
+#include "src/BigNumberMath/BigNumberMath.h"
 
 BigNumber findjd(int year, int month, const int &day, const int &timezone, const int &hour, const int &minute, const int &second);
 BigNumber TimeInJulianCenturies(const BigNumber &jd);

SunCalculations.h

@@ -1,7 +1,7 @@
 #ifndef suncalculations_h
 #define suncalculations_h
 
-#include <BigNumber.h>
+#include "src/BigNumber/BigNumber.h"
 
 void findSunsAltAndAzOne(const int &year, const int &month, const int &day, const int &timezone, const int &hour, const int &minute, const int &second, const float &latitude, const float &longitude);
 void findSunsAltAndAzOne(const int &year, const int &month, const int &day, const int &timezone, const int &hour, const int &minute, const int &second, const BigNumber &latitude, const BigNumber &longitude);