Index: trunk/psphot/src/psphotFitSourcesLinear.c
===================================================================
--- trunk/psphot/src/psphotFitSourcesLinear.c	(revision 31452)
+++ trunk/psphot/src/psphotFitSourcesLinear.c	(revision 32348)
@@ -17,4 +17,7 @@
     bool status = true;
 
+    fprintf (stdout, "\n");
+    psLogMsg ("psphot", PS_LOG_INFO, "--- psphot Fit Source (Linear) ---");
+
     // select the appropriate recipe information
     psMetadata *recipe  = psMetadataLookupPtr (&status, config->recipes, PSPHOT_RECIPE);
@@ -23,6 +26,11 @@
     int num = psphotFileruleCount(config, filerule);
 
+    // skip the chisq image (optionally?)
+    int chisqNum = psMetadataLookupS32 (&status, config->arguments, "PSPHOT.CHISQ.NUM");
+    if (!status) chisqNum = -1;
+
     // loop over the available readouts
     for (int i = 0; i < num; i++) {
+        if (i == chisqNum) continue; // skip chisq image
 
         // find the currently selected readout
@@ -190,4 +198,5 @@
         pmModel *model = pmSourceGetModel (&isPSF, source);
 
+	// clear the 'mark' pixels and remask on the fit aperture 
         psImageMaskPixels (source->maskObj, "AND", PS_NOT_IMAGE_MASK(markVal));
         psImageKeepCircle (source->maskObj, source->peak->x, source->peak->y, model->fitRadius, "OR", markVal);
@@ -349,5 +358,8 @@
         model->dparams->data.F32[PM_PAR_I0] = errors->data.F32[i];
 
-        // subtract object
+	// clear the 'mark' pixels so the subtraction covers the full window
+        psImageMaskPixels (source->maskObj, "AND", PS_NOT_IMAGE_MASK(markVal));
+
+        // subtract object & add noise
         pmSourceSub (source, PM_MODEL_OP_FULL, maskVal);
     }
@@ -374,5 +386,5 @@
     psFree (border);
 
-    psLogMsg ("psphot.ensemble", PS_LOG_INFO, "measure ensemble of PSFs: %f sec\n", psTimerMark ("psphot.linear"));
+    psLogMsg ("psphot.ensemble", PS_LOG_WARN, "measure ensemble of PSFs: %f sec\n", psTimerMark ("psphot.linear"));
 
     psphotVisualPlotChisq (sources);