Index: /trunk/MagicSoft/Cosy/main/MTracking.cc
===================================================================
--- /trunk/MagicSoft/Cosy/main/MTracking.cc	(revision 9558)
+++ /trunk/MagicSoft/Cosy/main/MTracking.cc	(revision 9559)
@@ -227,9 +227,10 @@
     if (fTrackType==(kEMoon|0x100))
     {
+        // FIXME: Read file only once!
         MMoonPointing moon("MoonShadowOffsets.root");
         if (moon.IsZombie())
         {
-            gLog << warn << "WARNING - Calculation of moon shadow failed." << endl;
-            return;
+            gLog << err << "ERROR - Could not initialize MMoonPointing." << endl;
+            return kFALSE;
         }
 
@@ -241,5 +242,8 @@
         const ZdAz za = sla.GetZdAzRad();
         if (!moon.CalcPosition(za, srcpos, pointpos))
+        {
+            gLog << err << "ERROR - Calculation of moon shadow pointing position failed." << endl;
             return kFALSE;
+        }
 
         sla.Set(pointpos);
Index: /trunk/MagicSoft/Cosy/main/MTracking.h
===================================================================
--- /trunk/MagicSoft/Cosy/main/MTracking.h	(revision 9558)
+++ /trunk/MagicSoft/Cosy/main/MTracking.h	(revision 9559)
@@ -33,7 +33,7 @@
     MLog   *fOut;
 
-    void UpdateSlalib(SlaPlanets &sla);
-    void UpdateSlalib(Double_t dt=0);
-    void UpdateSlalib(SlaPlanets &sla, Double_t mjd);
+    Bool_t UpdateSlalib(SlaPlanets &sla);
+    Bool_t UpdateSlalib(Double_t dt=0);
+    Bool_t UpdateSlalib(SlaPlanets &sla, Double_t mjd);
 
     bool SetVelocity(const ZdAz &v);