Index: /trunk/psModules/src/objects/pmSourceMoments.c
===================================================================
--- /trunk/psModules/src/objects/pmSourceMoments.c	(revision 42480)
+++ /trunk/psModules/src/objects/pmSourceMoments.c	(revision 42481)
@@ -231,10 +231,21 @@
     }
 
+    // we only update the centroid if the position is not supplied from elsewhere
+    bool skipCentroid = false;
+    skipCentroid |= (source->mode  & PM_SOURCE_MODE_EXTERNAL); // skip externally supplied positions
+    skipCentroid |= (source->mode2 & PM_SOURCE_MODE2_MATCHED); // skip sources defined by other image positions
+
     // if we have less than (1/4) of the possible pixels (in circle or box), force a retry
     int minPixels = PS_MIN(0.75*R2, source->pixels->numCols*source->pixels->numRows/4.0);
 
     // XXX EAM - the limit is a bit arbitrary.  make it user defined?
-    if ((numPixels < minPixels) || (Sum <= 0)) {
+    if (numPixels < minPixels) {
 	psTrace ("psModules.objects", 3, "insufficient valid pixels (%d vs %d; %f) for source\n", numPixels, minPixels, Sum);
+	return (false);
+    }
+
+    // only skip negative sum sources if the sources are not forced
+    if (!skipCentroid && (Sum <= 0)) {
+	psTrace ("psModules.objects", 3, "insufficient significant pixels (%d vs %d; %f) for source\n", numPixels, minPixels, Sum);
 	return (false);
     }
@@ -243,12 +254,7 @@
     float Mx = X1/Sum;
     float My = Y1/Sum;
-    if ((fabs(Mx) > radius) || (fabs(My) > radius)) {
-	psTrace ("psModules.objects", 3, "extreme centroid swing; invalid peak %d, %d\n", source->peak->x, source->peak->y);
-	return (false);
-    }
     if ((fabs(Mx) > 2.0) || (fabs(My) > 2.0)) {
 	psTrace ("psModules.objects", 3, " big centroid swing; ok peak? %d, %d\n", source->peak->x, source->peak->y);
     }
-
     psTrace ("psModules.objects", 5, "id: %d, sky: %f  Mx: %f  My: %f  Sum: %f  X1: %f  Y1: %f  Npix: %d\n", source->id, sky, Mx, My, Sum, X1, Y1, numPixels);
 
@@ -258,13 +264,12 @@
     // 0.5 PIX: moments are calculated using the pixel index and converted here to pixel coords
 
-    // we only update the centroid if the position is not supplied from elsewhere
-    bool skipCentroid = false;
-    skipCentroid |= (source->mode  & PM_SOURCE_MODE_EXTERNAL); // skip externally supplied positions
-    skipCentroid |= (source->mode2 & PM_SOURCE_MODE2_MATCHED); // skip sources defined by other image positions
-
     if (skipCentroid) {
 	source->moments->Mx = source->peak->xf;
 	source->moments->My = source->peak->yf;
     } else {
+        if ((fabs(Mx) > radius) || (fabs(My) > radius)) {
+	    psTrace ("psModules.objects", 3, "extreme centroid swing; invalid peak %d, %d\n", source->peak->x, source->peak->y);
+	    return (false);
+	}
 	source->moments->Mx = Mx + xGuess;
 	source->moments->My = My + yGuess;