Index: branches/eam_branches/ipp-20100621/psphot/src/psphotExtendedSourceFits.c
===================================================================
--- branches/eam_branches/ipp-20100621/psphot/src/psphotExtendedSourceFits.c	(revision 28686)
+++ branches/eam_branches/ipp-20100621/psphot/src/psphotExtendedSourceFits.c	(revision 28687)
@@ -210,5 +210,5 @@
           pmModel *modelFit = NULL;
           if (convolved) {
-              modelFit = psphotPSFConvModel (readout, source, modelType, maskVal, markVal, psfSize);
+              modelFit = psphotFitPCM (readout, source, fitOptions, modelType, maskVal, markVal, psfSize);
               if (!modelFit) {
                   psTrace ("psphot", 5, "failed to fit psf-conv model for object at %f, %f", source->moments->Mx, source->moments->My);
Index: branches/eam_branches/ipp-20100621/psphot/src/psphotSourceFits.c
===================================================================
--- branches/eam_branches/ipp-20100621/psphot/src/psphotSourceFits.c	(revision 28686)
+++ branches/eam_branches/ipp-20100621/psphot/src/psphotSourceFits.c	(revision 28687)
@@ -476,6 +476,45 @@
 }
 
+pmModel *psphotFitPCM (pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, pmModelType modelType, psImageMaskType maskVal, psImageMaskType markVal) {
+
+    pmSourceFitOptions options = *fitOptions;
+
+    NfitPCM ++;
+
+    // maskVal is used to test for rejected pixels, and must include markVal
+    maskVal |= markVal;
+
+    // psTraceSetLevel("psLib.math.psMinimizeLMChi2", 5);
+
+    // use the source moments, etc to guess basic model parameters
+    pmModel *EXT = pmSourceModelGuess (source, modelType);
+    if (!EXT) {
+	psTrace ("psphot", 5, "failed to generate a model for source: moments: %f %f\n", source->moments->Mxx, source->moments->Myy);
+	return NULL;
+    }
+
+    if ((source->moments->Mxx < 1e-3) || (source->moments->Myy < 1e-3)) {
+        psTrace ("psphot", 5, "problem source: moments: %f %f\n", source->moments->Mxx, source->moments->Myy);
+    }
+
+    // for sersic models, use a grid search to choose an index, then float the params there
+    if (modelType == pmModelClassGetType("PS_MODEL_SERSIC")) {
+    	psphotFitSersicIndexPCM (source, EXT, fitOptions, maskVal);
+    }
+
+    if (modelType == pmModelClassGetType("PS_MODEL_SERSIC")) {
+	options.mode = PM_SOURCE_FIT_NO_INDEX;
+    } else {
+	options.mode = PM_SOURCE_FIT_EXT;
+    }
+    pmSourceFitPCM (source, EXT, &options, maskVal);
+
+    // psTraceSetLevel("psLib.math.psMinimizeLMChi2", 0);
+    return (EXT);
+}
+
 // note that these should be 1/2n of the standard sersic index
 float indexGuess[] = {0.5, 0.33, 0.25, 0.167, 0.125, 0.083};
+define N_INDEX_GUESS 6
 
 // A sersic model is very sensitive to the index.  attempt to find the index first by grid search in just the index
@@ -491,8 +530,8 @@
     options.nIter = 3;
 
-    float xMin, chiSquare[3];
+    float xMin, chiSquare[N_INDEX_GUESS];
     int iMin;
 
-    for (int i = 0; i < 3; i++) {
+    for (int i = 0; i < N_INDEX_GUESS; i++) {
 	model->params->data.F32[PM_PAR_7] = indexGuess[i];
 	model->modelGuess(model, source);
@@ -516,2 +555,40 @@
     return true;
 }
+
+// A sersic model is very sensitive to the index.  attempt to find the index first by grid search in just the index
+// for a sersic model, attempt to fit just the index and normalization with a modest number of iterations
+bool psphotFitSersicIndexPCM (pmSource *source, pmModel *model, pmSourceFitOptions *fitOptions, psImageMaskType maskVal) {
+
+    assert (model->type == pmModelClassGetType("PS_MODEL_SERSIC"));
+
+    pmSourceFitOptions options = *fitOptions;
+    
+    // fit EXT (not PSF) model (set/unset the pixel mask)
+    options.mode = PM_SOURCE_FIT_NO_INDEX;
+    options.nIter = 3;
+
+    float xMin, chiSquare[N_INDEX_GUESS];
+    int iMin;
+
+    for (int i = 0; i < N_INDEX_GUESS; i++) {
+	model->params->data.F32[PM_PAR_7] = indexGuess[i];
+	model->modelGuess(model, source);
+	pmSourceFitPCM (source, model, &options, maskVal);
+	chiSquare[i] = model->chisq;
+	if (i == 0) {
+	    xMin = chiSquare[i];
+	    iMin = i;
+	} else {
+	    if (chiSquare[i] < xMin) {
+		xMin = chiSquare[i];
+		iMin = i;
+	    }
+	}
+    }
+
+    model->flags = PM_MODEL_STATUS_NONE; // do not attempt to handle failures here, let the next iteration deal with it
+    model->params->data.F32[PM_PAR_7] = indexGuess[iMin];
+    model->modelGuess(model, source);
+
+    return true;
+}