Index: /branches/eam_branches/20090715/psModules/src/objects/models/pmModel_GAUSS.c
===================================================================
--- /branches/eam_branches/20090715/psModules/src/objects/models/pmModel_GAUSS.c	(revision 25302)
+++ /branches/eam_branches/20090715/psModules/src/objects/models/pmModel_GAUSS.c	(revision 25303)
@@ -29,4 +29,6 @@
 
 // the model is a function of the pixel coordinate (pixcoord[0,1] = x,y)
+// 0.5 PIX: the parameters are defined in terms of pixel coords, so the incoming pixcoords
+// values need to be pixel coords
 psF32 PM_MODEL_FUNC(psVector *deriv,
                     const psVector *params,
Index: /branches/eam_branches/20090715/psModules/src/objects/pmGrowthCurveGenerate.c
===================================================================
--- /branches/eam_branches/20090715/psModules/src/objects/pmGrowthCurveGenerate.c	(revision 25302)
+++ /branches/eam_branches/20090715/psModules/src/objects/pmGrowthCurveGenerate.c	(revision 25303)
@@ -65,4 +65,5 @@
 
 	    // use the center of the center pixel of the image
+	    // 0.5 PIX: is this offset needed? probably -- the psf model uses 0.5,0.5 as the center, double check
 	    float xc = (int)(ix*readout->image->numCols + 0.5*readout->image->numCols) + readout->image->col0 + 0.5;
 	    float yc = (int)(iy*readout->image->numRows + 0.5*readout->image->numRows) + readout->image->row0 + 0.5;
Index: /branches/eam_branches/20090715/psModules/src/objects/pmPSFtry.c
===================================================================
--- /branches/eam_branches/20090715/psModules/src/objects/pmPSFtry.c	(revision 25302)
+++ /branches/eam_branches/20090715/psModules/src/objects/pmPSFtry.c	(revision 25303)
@@ -191,4 +191,5 @@
 
         // set object mask to define valid pixels
+	// XXX 0.5 PIX: is the circle symmetric about the peak coordinate (given 0.5,0.5 center)?
         psImageKeepCircle (source->maskObj, source->peak->x, source->peak->y, options->radius, "OR", markVal);
 
Index: /branches/eam_branches/20090715/psModules/src/objects/pmSourceFitModel.c
===================================================================
--- /branches/eam_branches/20090715/psModules/src/objects/pmSourceFitModel.c	(revision 25302)
+++ /branches/eam_branches/20090715/psModules/src/objects/pmSourceFitModel.c	(revision 25303)
@@ -96,6 +96,7 @@
 
             // Convert i/j to image space:
-            coord->data.F32[0] = (psF32) (j + source->pixels->col0);
-            coord->data.F32[1] = (psF32) (i + source->pixels->row0);
+	    // 0.5 PIX: the coordinate values must be in pixel coords, not index	    
+            coord->data.F32[0] = (psF32) (j + 0.5 + source->pixels->col0);
+            coord->data.F32[1] = (psF32) (i + 0.5 + source->pixels->row0);
             x->data[nPix] = (psPtr *) coord;
             y->data.F32[nPix] = source->pixels->data.F32[i][j];
Index: /branches/eam_branches/20090715/psModules/src/objects/pmSourceFitSet.c
===================================================================
--- /branches/eam_branches/20090715/psModules/src/objects/pmSourceFitSet.c	(revision 25302)
+++ /branches/eam_branches/20090715/psModules/src/objects/pmSourceFitSet.c	(revision 25303)
@@ -483,6 +483,7 @@
 
             // Convert i/j to image space:
-            coord->data.F32[0] = (psF32) (j + source->pixels->col0);
-            coord->data.F32[1] = (psF32) (i + source->pixels->row0);
+	    // 0.5 PIX: the coordinate values must be in pixel coords, not index	    
+            coord->data.F32[0] = (psF32) (j + 0.5 + source->pixels->col0);
+            coord->data.F32[1] = (psF32) (i + 0.5 + source->pixels->row0);
             x->data[nPix] = (psPtr *) coord;
             y->data.F32[nPix] = source->pixels->data.F32[i][j];