Index: trunk/MagicSoft/Mars/mpointing/MPointingDevCalc.cc
===================================================================
--- trunk/MagicSoft/Mars/mpointing/MPointingDevCalc.cc	(revision 8985)
+++ trunk/MagicSoft/Mars/mpointing/MPointingDevCalc.cc	(revision 8989)
@@ -491,4 +491,10 @@
     fSkip.Reset();
 
+    // In cases in which ReInit isn't called right in time (e.g. if
+    // the first starguider event comes before the first data event)
+    fNsbSum   =  0;
+    fNsbSq    =  0;
+    fNsbCount =  0;
+
     return fDeviation ? kTRUE : kFALSE;
 }