Index: trunk/psastro/src/psastroAstromGuess.c
===================================================================
--- trunk/psastro/src/psastroAstromGuess.c	(revision 31333)
+++ trunk/psastro/src/psastroAstromGuess.c	(revision 39926)
@@ -75,5 +75,6 @@
     pmFPA *fpa = input->fpa;
 
-    if (DEBUG) psastroDumpCorners ("corners.up.guess1.dat", "corners.dn.guess1.dat", fpa);
+    // this call only works if we have loaded a model : seg fault if not
+    if (DEBUG && useModel) psastroDumpCorners ("corners.up.guess1.dat", "corners.dn.guess1.dat", fpa);
 
     // load mosaic-level astrometry?
@@ -91,4 +92,10 @@
             if (!psastroAstromGuessSetChip (fpa, chip, view, pixelScale, bilevelAstrometry)) continue;
         }
+
+	if (!chip->toFPA || !chip->fromFPA) {
+	  char *name = psMetadataLookupStr (NULL, chip->concepts, "CHIP.NAME");
+	  fprintf (stderr, "no astrom model for %s, skipping\n", name);
+	  continue;
+	}
 
         if (newFPA) {
@@ -312,4 +319,10 @@
     while ((chip = pmFPAviewNextChip (view, fpa, 1)) != NULL) {
         if (!chip->process || !chip->file_exists || !chip->data_exists) { continue; }
+
+	if (!chip->toFPA || !chip->fromFPA) {
+	  char *name = psMetadataLookupStr (NULL, chip->concepts, "CHIP.NAME");
+	  fprintf (stderr, "no astrom model for %s, skipping\n", name);
+	  continue;
+	}
 
         // XXX we are currently inconsistent with marking the good vs the bad data