Index: trunk/ppSub/src/ppSubMatchPSFs.c
===================================================================
--- trunk/ppSub/src/ppSubMatchPSFs.c	(revision 26971)
+++ trunk/ppSub/src/ppSubMatchPSFs.c	(revision 26974)
@@ -144,10 +144,10 @@
     psAssert (refSources, "missing refSources?");
 
-    float inFWHM = psMetadataLookupF32(NULL, inRO->parent->parent->analysis, "CHIP.SEEING"); // FWHM for input
-    if (!isfinite(inFWHM)) {
+    float inFWHM = psMetadataLookupF32(NULL, inRO->parent->parent->concepts, "CHIP.SEEING"); // FWHM for input
+    if (!isfinite(inFWHM) || inFWHM == 0.0) {
         inFWHM = subImagePSF(data, inRO, inSources);
     }
-    float refFWHM = psMetadataLookupF32(NULL, refRO->parent->parent->analysis, "CHIP.SEEING"); // FWHM for ref
-    if (!isfinite(refFWHM)) {
+    float refFWHM = psMetadataLookupF32(NULL, refRO->parent->parent->concepts, "CHIP.SEEING"); // FWHM for ref
+    if (!isfinite(refFWHM) || refFWHM == 0.0) {
         refFWHM = subImagePSF(data, refRO, refSources);
     }