diff --git a/pygac/gac_io.py b/pygac/gac_io.py
index 4333d5b5..8b08b2d5 100644
--- a/pygac/gac_io.py
+++ b/pygac/gac_io.py
@@ -519,7 +519,7 @@ def avhrrGAC_io(satellite_name, xutcs, startdate, enddate, starttime, endtime,
     g4.attrs["dataset_name"] = np.string_('Solar azimuth angle')
     g4.attrs["units"] = np.string_('Deg')
     g4.attrs["gain"] = np.float32(0.01)
-    g4.attrs["offset"] = np.float32(180.0)
+    g4.attrs["offset"] = np.float32(0.0)
     g4.attrs["missingdata"] = np.int32(MISSING_DATA)
     g4.attrs["nodata"] = np.int32(MISSING_DATA)
     g4.attrs["starttime"] = np.string_(starttime[0:6])
@@ -532,7 +532,7 @@ def avhrrGAC_io(satellite_name, xutcs, startdate, enddate, starttime, endtime,
     g5.attrs["dataset_name"] = np.string_('Satellite azimuth angle')
     g5.attrs["units"] = np.string_('Deg')
     g5.attrs["gain"] = np.float32(0.01)
-    g5.attrs["offset"] = np.float32(180.0)
+    g5.attrs["offset"] = np.float32(0.0)
     g5.attrs["missingdata"] = np.int32(MISSING_DATA)
     g5.attrs["nodata"] = np.int32(MISSING_DATA)
     g5.attrs["starttime"] = np.string_(starttime[0:6])