Index: trunk/psphot/src/psphotSignificanceImage.c
===================================================================
--- trunk/psphot/src/psphotSignificanceImage.c	(revision 35688)
+++ trunk/psphot/src/psphotSignificanceImage.c	(revision 42088)
@@ -105,4 +105,5 @@
 	      //	      float v2 = value + PS_SQR(value/100.0);
 	      // CZW 2013-06-20: I don't think this hack was helping.
+	      // EAM 2021-12-21: see note below about divots in the significance image
 	      float v2 = value;
 	      smooth_wt->data.F32[j][i] = factor * PS_SQR(v2) / smooth_wt->data.F32[j][i];
@@ -122,4 +123,13 @@
     }
     psImageConvolveSetThreads(oldThreads);
+
+    // We now have the significance image and the signal image.  In some cases (e.g.,
+    // stacks), the variance on pixels in the cores of stars is elevated compared to pure
+    // poisson statistics.  In this case, especially at high signal levels, the ratio of
+    // signal / noise in the core of the star can be lower than the surrounding ring of
+    // pixels.  This results in a divot in the center of the star in the significance
+    // image.  the apparent peak of the significance is then not centered on the star and
+    // chaos ensues.  A possible fix is to use the signal image for signficance for
+    // the high S/N detection pass.
 
     pmReadout *significanceRO = pmReadoutAlloc(NULL);