Index: trunk/psphot/src/psphotEnsemblePSF.c
===================================================================
--- trunk/psphot/src/psphotEnsemblePSF.c	(revision 10076)
+++ trunk/psphot/src/psphotEnsemblePSF.c	(revision 10096)
@@ -10,5 +10,5 @@
 // the analysis is performed wrt the simulated pixel values
 
-static bool SetBorderT (psSparseBorder *border, pmReadout *readout, psArray *refSources, psArray *fitSources, psVector *index, bool fitSlope);
+static bool SetBorderT (psSparseBorder *border, pmReadout *readout, psArray *refSources, psArray *fitSources, psVector *index, bool fitSlope, bool constant_weights);
 
 bool psphotEnsemblePSF (pmReadout *readout, psArray *refSources, psMetadata *recipe, pmPSF *psf, bool final) {
@@ -162,5 +162,5 @@
     // set the sky, sky_x, sky_y components of border matrix
     // XXX ignore sky slope terms for now
-    SetBorderT (border, readout, refSources, fitSources, index, false);
+    SetBorderT (border, readout, refSources, fitSources, index, false, CONSTANT_PHOTOMETRIC_WEIGHTS);
 
     psSparseConstraint constraint;
@@ -170,8 +170,9 @@
 
     // solve for normalization terms (need include local sky?)
-    # if (0)
+    # if (1)
     psVector *norm = NULL;
     psVector *skyfit = NULL;
     psSparseBorderSolve (&norm, &skyfit, constraint, border, 3);
+    fprintf (stderr, "skyfit: %f\n", skyfit->data.F32[0]);
     # else
     psVector *norm = psSparseSolve (NULL, constraint, sparse, 3);
@@ -226,5 +227,5 @@
 
 // calculate the weight terms for the sky fit component of the matrix
-static bool SetBorderT (psSparseBorder *border, pmReadout *readout, psArray *refSources, psArray *fitSources, psVector *index, bool fitSlope) {
+static bool SetBorderT (psSparseBorder *border, pmReadout *readout, psArray *refSources, psArray *fitSources, psVector *index, bool fitSlope, bool constant_weights) {
 
     // generate the image-wide weight terms
@@ -251,6 +252,6 @@
     psU8 **mask = readout->mask->data.U8;
 
-    double w, x, y, x2, xy, y2, xc, yc;
-    w = x = y = x2 = xy = y2 = 0;
+    double w, x, y, x2, xy, y2, xc, yc, wt, f, fo, fx, fy;
+    w = x = y = x2 = xy = y2 = fo = fx = fy = 0;
     
     int col0 = readout->image->col0;
@@ -260,13 +261,23 @@
 	for (int i = 0; i < readout->image->numCols; i++) {
 	    if (mask[j][i]) continue;
-	    w  +=       image[j][i]/weight[j][i];
+	    if (constant_weights) {
+		wt = 1.0;
+	    } else {
+		wt = weight[j][i];
+	    }
+	    f = image[j][i];
+	    w   += 1/wt;
+	    fo  += f/wt;
+
 	    if (!fitSlope) continue;
 	    xc = i + col0;
 	    yc = j + row0;
-	    x  +=    xc*image[j][i]/weight[j][i];
-	    y  +=    yc*image[j][i]/weight[j][i];
-	    x2 += xc*xc*image[j][i]/weight[j][i];
-	    xy += xc*yc*image[j][i]/weight[j][i];
-	    y2 += yc*yc*image[j][i]/weight[j][i];
+	    x  +=    xc/wt;
+	    y  +=    yc/wt;
+	    x2 += xc*xc/wt;
+	    xy += xc*yc/wt;
+	    y2 += yc*yc/wt;
+	    fx +=  f*xc/wt;
+	    fy +=  f*yc/wt;
 	}
     }
@@ -276,6 +287,9 @@
 
     // set the Border T elements
+    psSparseBorderElementG (border, 0, fo);
     psSparseBorderElementT (border, 0, 0, w);
     if (fitSlope) {
+	psSparseBorderElementG (border, 0, fx);
+	psSparseBorderElementG (border, 0, fy);
 	psSparseBorderElementT (border, 1, 0, x);
 	psSparseBorderElementT (border, 2, 0, y);