diff --git a/src/ctskymap/ctskymap.cpp b/src/ctskymap/ctskymap.cpp
index 1158aa5..2fce299 100644
--- a/src/ctskymap/ctskymap.cpp
+++ b/src/ctskymap/ctskymap.cpp
@@ -347,6 +347,9 @@ void ctskymap::get_parameters(void)
         // Throw exception if no input observation file is given
         require_inobs(G_GET_PARAMETERS);
 
+        // Throw exception if counts cube is given
+        require_inobs_nocube(G_GET_PARAMETERS);
+
         // Get observation container without response (not needed)
         m_obs = get_observations(false);