Index: trunk/Mars/mcorsika/MCorsikaRead.cc
===================================================================
--- trunk/Mars/mcorsika/MCorsikaRead.cc	(revision 19539)
+++ trunk/Mars/mcorsika/MCorsikaRead.cc	(revision 19540)
@@ -210,4 +210,10 @@
         *fLog << inf2 << "Run " << runid << " detected to be for the " << telid << "-th telescope." << endl;
 
+        if (fNumTelescopes<telid)
+        {
+            *fLog << err << "Position of telescope " << telid << " not defined." << endl;
+            return kERROR;
+        }
+
         *fLog << inf << "Telescope #" << telid << " [X/Y/Z (R)]: ";
         *fLog << fTelescopeX[telid-1] << "/";