diff --git a/Pysolar/__init__.py b/Pysolar/__init__.py
index 276ca2c..d018838 100644
--- a/Pysolar/__init__.py
+++ b/Pysolar/__init__.py
@@ -1 +1 @@
-from solar import *
+from .solar import *
diff --git a/Pysolar/constants.py b/Pysolar/constants.py
index 49c1f25..22658ee 100644
--- a/Pysolar/constants.py
+++ b/Pysolar/constants.py
@@ -40,7 +40,8 @@
 
 """
 
-def buildPolyFit((a, b, c, d)): 
+def buildPolyFit(params): 
+    (a, b, c, d) = params
     return (lambda x: a + b * x + c * x ** 2 + (x ** 3) / d)
 
 def buildPolyDict():
diff --git a/Pysolar/elevation.py b/Pysolar/elevation.py
index 16a0709..9eea89a 100644
--- a/Pysolar/elevation.py
+++ b/Pysolar/elevation.py
@@ -36,7 +36,7 @@ def GetPressureWithElevation(h, Ps=101325.00, Ts=288.15, Tl=-0.0065, Hb=0.0, R=8
 	#M= Molar mass of Earth's atmosphere = 0.0289644 kg/mol
 	#P=Ps*(Ts/((Ts+Tl)*(h-Hb)))^((g*M)/(R*Tl))
 	#returns pressure in pascals
-	if h>11000.0: print"WARNING: Elevation used exceeds the recommended maximum elevation for this function (11,000m)"
+	if h>11000.0: print("WARNING: Elevation used exceeds the recommended maximum elevation for this function (11,000m)")
 	theDenominator = Ts+(Tl*(h-Hb))
 	theExponent=(g*M)/(R*Tl)
 	return Ps*(Ts/theDenominator)**theExponent
@@ -51,12 +51,12 @@ def GetTemperatureWithElevation(h, Ts=288.15, Tl=-0.0065):
 	return Ts+(h*Tl)
 
 def ElevationTest():
-	print "Elevation(m) Pressure(Pa) Temperature(K)"
+	print("Elevation(m) Pressure(Pa) Temperature(K)")
 	h=0
 	for i in range(11):
 		P=GetPressureWithElevation(h)
 		T=GetTemperatureWithElevation(h)
-		print "%i %i %i" % (h, P, T)
+		print("%i %i %i" % (h, P, T))
 		h=h+1000
 
 
diff --git a/Pysolar/radiation.py b/Pysolar/radiation.py
index b9616e0..2cf4704 100644
--- a/Pysolar/radiation.py
+++ b/Pysolar/radiation.py
@@ -20,7 +20,7 @@
 """Calculate different kinds of radiation components via default values
 
 """
-import solar
+#from . import solar
 import math
 
 def GetAirMassRatio(altitude_deg):
diff --git a/Pysolar/simulate.py b/Pysolar/simulate.py
index d6e85af..8e068a0 100644
--- a/Pysolar/simulate.py
+++ b/Pysolar/simulate.py
@@ -21,8 +21,8 @@
 
 """
 import datetime
-import radiation
-import solar
+from . import radiation
+from . import solar
 from math import *
 
 def BuildTimeList(start_utc_datetime, end_utc_datetime, step_minutes):
@@ -31,7 +31,7 @@ def BuildTimeList(start_utc_datetime, end_utc_datetime, step_minutes):
 	time_list = []
 	span = end_utc_datetime - start_utc_datetime
 	dt = datetime.timedelta(seconds = step)
-	return map(lambda n: start_utc_datetime + dt * n, range((span.days * 86400 + span.seconds) / step))
+	return [start_utc_datetime + dt * n for n in range((span.days * 86400 + span.seconds) / step)]
 
 def CheckAgainstHorizon(power):
     (time, alt, az, radiation, shade) = power
@@ -58,7 +58,7 @@ def SimulateSpan(latitude_deg, longitude_deg, horizon, start_utc_datetime, end_u
 		solar.GetAzimuth(latitude_deg, longitude_deg, time, elevation)
 		) for time in time_list]	
 	power_list = [(time, alt, az, radiation.GetRadiationDirect(time, alt), horizon[int(az)]) for (time, alt, az) in angles_list]
-	return filter(CheckAgainstHorizon, power_list)
+	return list(filter(CheckAgainstHorizon, power_list))
 		
 #		xs = shade.GetXShade(width, 120, azimuth_deg)
 #		ys = shade.GetYShade(height, 120, altitude_deg)
diff --git a/Pysolar/solar.py b/Pysolar/solar.py
index 2235704..af38e90 100644
--- a/Pysolar/solar.py
+++ b/Pysolar/solar.py
@@ -24,9 +24,9 @@
 """
 import math
 import datetime
-import constants
-import julian
-import radiation
+from . import constants
+from . import julian
+from . import radiation
 
 #if __name__ == "__main__":
 def SolarTest():
@@ -40,7 +40,7 @@ def SolarTest():
 		azimuth_deg = GetAzimuth(latitude_deg, longitude_deg, d)
 		power = radiation.GetRadiationDirect(d, altitude_deg)
 		if (altitude_deg > 0):
-			print timestamp, "UTC", altitude_deg, azimuth_deg, power
+			print(timestamp, "UTC", altitude_deg, azimuth_deg, power)
 		d = d + thirty_minutes
 
 def EquationOfTime(day):
diff --git a/Pysolar/testsolar.py b/Pysolar/testsolar.py
index 073b884..e918c17 100644
--- a/Pysolar/testsolar.py
+++ b/Pysolar/testsolar.py
@@ -19,10 +19,10 @@
 #    You should have received a copy of the GNU General Public License along
 #    with Pysolar. If not, see <http://www.gnu.org/licenses/>.
 
-import solar
-import constants
-import julian
-import elevation
+from . import solar
+from . import constants
+from . import julian
+from . import elevation
 import datetime
 import unittest
 
diff --git a/Pysolar/util.py b/Pysolar/util.py
index 8598bb0..dd55e30 100644
--- a/Pysolar/util.py
+++ b/Pysolar/util.py
@@ -35,7 +35,7 @@
 import math
 import pytz
 from pytz import all_timezones
-import solar
+from . import solar
 
 # Some default constants
 
diff --git a/setup.py b/setup.py
index 97d6193..eaab3a0 100644
--- a/setup.py
+++ b/setup.py
@@ -14,7 +14,9 @@
     'Topic :: Scientific/Engineering',
     'Topic :: Scientific/Engineering :: Atmospheric Science',
     'Topic :: Scientific/Engineering :: Mathematics',
-    'Topic :: Software Development :: Libraries :: Python Modules']
+    'Topic :: Software Development :: Libraries :: Python Modules',
+    'Programming Language :: Python :: 2',
+    'Programming Language :: Python :: 3']
 
 
 setup(name='Pysolar',