Index: /trunk/psphot/src/psphotEvalPSF.c
===================================================================
--- /trunk/psphot/src/psphotEvalPSF.c	(revision 10203)
+++ /trunk/psphot/src/psphotEvalPSF.c	(revision 10204)
@@ -21,10 +21,14 @@
 // floor for DS value 
 // XXX EAM : add to configuration?
-# define MIN_DS 0.01
 
 static float SATURATION;
 static float PSF_MIN_SN;
+static float PSF_MIN_DS;
 static float PSF_MAX_CHI;
 static float PSF_SHAPE_NSIGMA;
+static float PSF_DSX_MEAN;
+static float PSF_DSY_MEAN;
+static float PSF_DSX_STDEV;
+static float PSF_DSY_STDEV;
 
 bool psphotInitLimitsPSF (psMetadata *recipe) {
@@ -37,4 +41,11 @@
     PSF_MAX_CHI      = psMetadataLookupF32 (&status, recipe, "PSF_MAX_CHI");
     PSF_SHAPE_NSIGMA = psMetadataLookupF32 (&status, recipe, "PSF_SHAPE_NSIGMA");
+    PSF_MIN_DS       = psMetadataLookupF32 (&status, recipe, "PSF_MIN_DS");
+    if (!status) PSF_MIN_DS = 0.01;
+
+    PSF_DSX_MEAN     = psMetadataLookupF32 (&status, recipe, "DSX_MEAN");
+    PSF_DSY_MEAN     = psMetadataLookupF32 (&status, recipe, "DSY_MEAN");
+    PSF_DSX_STDEV    = psMetadataLookupF32 (&status, recipe, "DSX_STDV");
+    PSF_DSY_STDEV    = psMetadataLookupF32 (&status, recipe, "DSY_STDV");
 
     return true;
@@ -101,5 +112,5 @@
     }
 
-    SN  = model->params->data.F32[PM_PAR_I0]/model->dparams->data.F32[1];
+    SN  = model->params->data.F32[PM_PAR_I0]/model->dparams->data.F32[PM_PAR_I0];
     SX  = model->params->data.F32[PM_PAR_SXX];
     SY  = model->params->data.F32[PM_PAR_SYY];
@@ -109,6 +120,6 @@
 
     // swing of sigma_x,y in sigmas
-    nSx = dSX / hypot (MIN_DS, (SX / SN));
-    nSy = dSY / hypot (MIN_DS, (SY / SN));
+    nSx = (dSX - PSF_DSX_MEAN) / (PSF_DSX_STDEV * PS_MAX (PSF_MIN_DS, (SX / SN)));
+    nSy = (dSY - PSF_DSY_MEAN) / (PSF_DSY_STDEV * PS_MAX (PSF_MIN_DS, (SY / SN)));
 
     // assign PM_SOURCE_MODE_GOODSTAR to bright objects within PSF region of dparams[]
@@ -118,16 +129,25 @@
     keep &= (SN > PSF_MIN_SN);
     keep &= (Chi < PSF_MAX_CHI);
-    if (keep) return true;
+    if (keep) {
+	if (source->mode & PM_SOURCE_MODE_PSFSTAR) {
+	    psTrace ("psphot", 7, "PSFSTAR kept (%f, %f  :  %f %f : %f %f : %f %f)\n", 
+		     model->params->data.F32[PM_PAR_XPOS], model->params->data.F32[PM_PAR_YPOS], dSX, nSx, dSY, nSy, SN, Chi);
+	}
+	return true;
+    }
 
     // this source is not a star, warn if it was a PSFSTAR
     if (source->mode & PM_SOURCE_MODE_PSFSTAR) {
-	psLogMsg ("psphot", 5, "PSFSTAR demoted based on fit quality   (%f, %f  :  %f %f %f %f)\n", 
-		  model->params->data.F32[PM_PAR_XPOS], model->params->data.F32[PM_PAR_YPOS], nSx, nSy, SN, Chi);
+	psTrace ("psphot", 5, "PSFSTAR demoted based on fit quality   (%f, %f  :  %f %f : %f %f : %f %f)\n", 
+		  model->params->data.F32[PM_PAR_XPOS], model->params->data.F32[PM_PAR_YPOS], dSX, nSx, dSY, nSy, SN, Chi);
     } else {
-	psLogMsg ("psphot", 5, "fails PSF fit (%f, %f  :  %f %f %f %f)\n", 
-		  model->params->data.F32[PM_PAR_XPOS], model->params->data.F32[PM_PAR_YPOS], nSx, nSy, SN, Chi);
-    }
-
-    // object appears to be small, suspected defect
+	psTrace ("psphot", 5, "fails PSF fit (%f, %f  :  %f %f : %f %f : %f %f)\n", 
+		  model->params->data.F32[PM_PAR_XPOS], model->params->data.F32[PM_PAR_YPOS], dSX, nSx, dSY, nSy, SN, Chi);
+    }
+
+    // object appears to be small, suspected defect.  this is a weak indication for a defect: a
+    // large positive or negative swing can also come from the bright sources for which we are 
+    // more sensitive to the wings than for the faint sources.  
+    // XXX allow -NSIGMA and +NSIGMA to have different values?
     if ((nSx <= -PSF_SHAPE_NSIGMA) || (nSy <= -PSF_SHAPE_NSIGMA)) {
 	source->type = PM_SOURCE_TYPE_DEFECT;