diff --git a/.DS_Store b/.DS_Store
index 52224ac..bf7aa0e 100644
Binary files a/.DS_Store and b/.DS_Store differ
diff --git a/pyatmos/.DS_Store b/pyatmos/.DS_Store
index 480070a..da76f7d 100644
Binary files a/pyatmos/.DS_Store and b/pyatmos/.DS_Store differ
diff --git a/pyatmos/StandardAtmosphere/StandardAtmosphere.py b/pyatmos/StandardAtmosphere/StandardAtmosphere.py
index f49c896..0244f30 100644
--- a/pyatmos/StandardAtmosphere/StandardAtmosphere.py
+++ b/pyatmos/StandardAtmosphere/StandardAtmosphere.py
@@ -100,4 +100,4 @@ def isa(altitude,altitude_type='geometric'):
             h0 = geopotential_alt[i+1]
 
     density = pressure / (R * temperature)
-    return {'temperature':temperature,'pressure':pressure,'density':density}
\ No newline at end of file
+    return {'temperature[K]':temperature,'pressure[Pa]':pressure,'density[kg/m^3]':density}
\ No newline at end of file
diff --git a/pyatmos/__init__.py b/pyatmos/__init__.py
index 395a39d..438f062 100644
--- a/pyatmos/__init__.py
+++ b/pyatmos/__init__.py
@@ -2,4 +2,8 @@
 pyatmos package
 
 This package is an archive of scientific routines that implements the estimation of atmospheric properties for various atmosphere models.  
-'''    
\ No newline at end of file
+'''    
+
+from .StandardAtmosphere.StandardAtmosphere import isa
+from .msise.spaceweather import download_sw,read_sw
+from .msise.nrlmsise00 import nrlmsise00
\ No newline at end of file
diff --git a/pyatmos/msise/nrlmsise00.py b/pyatmos/msise/nrlmsise00.py
index 57888c5..eba99b8 100644
--- a/pyatmos/msise/nrlmsise00.py
+++ b/pyatmos/msise/nrlmsise00.py
@@ -49,6 +49,7 @@ nrlmsise00
 '''
 
 import numpy as np
+from astropy.time import Time
 from scipy.interpolate import CubicSpline
 from pyshtools.legendre import PLegendreA,PlmIndex
 import pkg_resources
@@ -1021,7 +1022,8 @@ def gts7(inputp,flags,gsurf,re):
 
 # ============================ nrlmsise00 =========================== #
 
-def nrlmsise00(t,lat,lon,alt,SW_OBS_PRE,omode,aphmode):
+def nrlmsise00(t,lat,lon,alt,SW_OBS_PRE,omode='Oxygen',aphmode='NoAph'):
+    t = Time(t)
     lon_wrap = wraplon(lon)
     t_yday = t.yday.split(':')
     t_ymd = t.iso.split()[0].split('-')