Index: trunk/psastro/src/psastroUtils.c
===================================================================
--- trunk/psastro/src/psastroUtils.c	(revision 12536)
+++ trunk/psastro/src/psastroUtils.c	(revision 12712)
@@ -38,5 +38,6 @@
 	    pmChip *chip = fpa->chips->data[i];
 	    if (!chip->process || !chip->file_exists) { continue; }
-	    
+	    if (!chip->toFPA) { continue; }
+
 	    pixelScale1 = hypot (chip->toFPA->x->coeff[1][0], chip->toFPA->x->coeff[0][1]);
 	    pixelScale2 = hypot (chip->toFPA->y->coeff[1][0], chip->toFPA->y->coeff[0][1]);
@@ -52,4 +53,5 @@
 	pmChip *chip = fpa->chips->data[i];
 	if (!chip->process || !chip->file_exists) { continue; }
+	if (!chip->toFPA) { continue; }
 
 	psPlaneTransform *toFPA = chip->toFPA;