diff --git a/src/ctobssim/ctobssim.cpp b/src/ctobssim/ctobssim.cpp
index 36aeb61..e04c7e9 100644
--- a/src/ctobssim/ctobssim.cpp
+++ b/src/ctobssim/ctobssim.cpp
@@ -690,7 +690,7 @@ void ctobssim::simulate_source(GCTAObservation* obs, const GModels& models,
                 
                     // Get sky model (NULL if not a sky model)
                     const GModelSky* model =
-                          dynamic_cast<const GModelSky*>(&models[i]);
+                          dynamic_cast<const GModelSky*>(models[i]);
 
                     // If we have a sky model then simulate photons
                     if (model != NULL) {
@@ -868,7 +868,7 @@ void ctobssim::simulate_background(GCTAObservation* obs,
 
             // Get model (NULL if not a radial acceptance model)
             const GCTAModelRadialAcceptance* model = 
-                  dynamic_cast<const GCTAModelRadialAcceptance*>(&models[i]);
+                  dynamic_cast<const GCTAModelRadialAcceptance*>(models[i]);
 
             // If we have a radial acceptance model then simulate events
             if (model != NULL) {