diff --git a/modules/util/geos_nav.py b/modules/util/geos_nav.py
index c7559b46ebf00123af13aa05f7086156882ed8aa..0162283417ce4e2e9815937798ccb2c54770d641 100644
--- a/modules/util/geos_nav.py
+++ b/modules/util/geos_nav.py
@@ -65,8 +65,8 @@ LOFF = 0.151844
 
 
 def goes_to_geos(lamda_goes, theta_goes):
-    theta_geos = np.asin(np.sin(theta_goes) * np.cos(lamda_goes))
-    lamda_geos = np.atan(np.tan(lamda_goes) / np.cos(theta_goes))
+    theta_geos = np.arcsin(np.sin(theta_goes) * np.cos(lamda_goes))
+    lamda_geos = np.arctan(np.tan(lamda_goes) / np.cos(theta_goes))
 
     return lamda_geos, theta_geos