diff --git a/generate/template/astronomy.py b/generate/template/astronomy.py
index f36520bc..a61bed66 100644
--- a/generate/template/astronomy.py
+++ b/generate/template/astronomy.py
@@ -378,6 +378,8 @@ _cls_t = [
     [      1290.0,       0.0,      0.0,     -556.0,     0.0,     0.0]
 ]
 
+_iaudata = list(zip(_nals_t, _cls_t))
+
 class _iau2000b:
     def __init__(self, time):
         t = time.tt / 36525
@@ -388,12 +390,12 @@ class _iau2000b:
         om  = math.fmod((450160.398036 - t * 6962890.5431),    _ASEC360) * _ASEC2RAD
         dp = 0
         de = 0
-        for i in range(77):
-            arg = math.fmod((_nals_t[i][0]*el + _nals_t[i][1]*elp + _nals_t[i][2]*f + _nals_t[i][3]*d + _nals_t[i][4]*om), _PI2)
+        for n, c in _iaudata:
+            arg = math.fmod((n[0]*el + n[1]*elp + n[2]*f + n[3]*d + n[4]*om), _PI2)
             sarg = math.sin(arg)
             carg = math.cos(arg)
-            dp += (_cls_t[i][0] + _cls_t[i][1] * t)*sarg + _cls_t[i][2]*carg
-            de += (_cls_t[i][3] + _cls_t[i][4] * t)*carg + _cls_t[i][5]*sarg
+            dp += (c[0] + c[1] * t)*sarg + c[2]*carg
+            de += (c[3] + c[4] * t)*carg + c[5]*sarg
         self.dpsi = -0.000135 + (dp * 1.0e-7)
         self.deps = +0.000388 + (de * 1.0e-7)
 
diff --git a/generate/template/old.py b/generate/template/old.py
index 39e83607..a2d6f9dc 100644
--- a/generate/template/old.py
+++ b/generate/template/old.py
@@ -378,6 +378,8 @@ _cls_t = [
     [      1290.0,       0.0,      0.0,     -556.0,     0.0,     0.0]
 ]
 
+_iaudata = list(zip(_nals_t, _cls_t))
+
 class _iau2000b:
     def __init__(self, time):
         t = time.tt / 36525
@@ -388,12 +390,12 @@ class _iau2000b:
         om  = math.fmod((450160.398036 - t * 6962890.5431),    _ASEC360) * _ASEC2RAD
         dp = 0
         de = 0
-        for i in range(77):
-            arg = math.fmod((_nals_t[i][0]*el + _nals_t[i][1]*elp + _nals_t[i][2]*f + _nals_t[i][3]*d + _nals_t[i][4]*om), _PI2)
+        for n, c in _iaudata:
+            arg = math.fmod((n[0]*el + n[1]*elp + n[2]*f + n[3]*d + n[4]*om), _PI2)
             sarg = math.sin(arg)
             carg = math.cos(arg)
-            dp += (_cls_t[i][0] + _cls_t[i][1] * t)*sarg + _cls_t[i][2]*carg
-            de += (_cls_t[i][3] + _cls_t[i][4] * t)*carg + _cls_t[i][5]*sarg
+            dp += (c[0] + c[1] * t)*sarg + c[2]*carg
+            de += (c[3] + c[4] * t)*carg + c[5]*sarg
         self.dpsi = -0.000135 + (dp * 1.0e-7)
         self.deps = +0.000388 + (de * 1.0e-7)
 
diff --git a/source/python/astronomy.py b/source/python/astronomy.py
index 7668e3b0..7ccab10f 100644
--- a/source/python/astronomy.py
+++ b/source/python/astronomy.py
@@ -469,6 +469,8 @@ _cls_t = [
     [      1290.0,       0.0,      0.0,     -556.0,     0.0,     0.0]
 ]
 
+_iaudata = list(zip(_nals_t, _cls_t))
+
 class _iau2000b:
     def __init__(self, time):
         t = time.tt / 36525
@@ -479,12 +481,12 @@ class _iau2000b:
         om  = math.fmod((450160.398036 - t * 6962890.5431),    _ASEC360) * _ASEC2RAD
         dp = 0
         de = 0
-        for i in range(77):
-            arg = math.fmod((_nals_t[i][0]*el + _nals_t[i][1]*elp + _nals_t[i][2]*f + _nals_t[i][3]*d + _nals_t[i][4]*om), _PI2)
+        for n, c in _iaudata:
+            arg = math.fmod((n[0]*el + n[1]*elp + n[2]*f + n[3]*d + n[4]*om), _PI2)
             sarg = math.sin(arg)
             carg = math.cos(arg)
-            dp += (_cls_t[i][0] + _cls_t[i][1] * t)*sarg + _cls_t[i][2]*carg
-            de += (_cls_t[i][3] + _cls_t[i][4] * t)*carg + _cls_t[i][5]*sarg
+            dp += (c[0] + c[1] * t)*sarg + c[2]*carg
+            de += (c[3] + c[4] * t)*carg + c[5]*sarg
         self.dpsi = -0.000135 + (dp * 1.0e-7)
         self.deps = +0.000388 + (de * 1.0e-7)