Index: trunk/psphot/src/psphotRadialProfile.c
===================================================================
--- trunk/psphot/src/psphotRadialProfile.c	(revision 15819)
+++ trunk/psphot/src/psphotRadialProfile.c	(revision 17396)
@@ -41,6 +41,15 @@
 
     int n = 0;
-    float Xo = source->modelEXT->params->data.F32[PM_PAR_XPOS] - source->pixels->col0;
-    float Yo = source->modelEXT->params->data.F32[PM_PAR_YPOS] - source->pixels->row0;
+    
+    float Xo = 0.0;
+    float Yo = 0.0;
+
+    if (source->modelEXT) {
+      Xo = source->modelEXT->params->data.F32[PM_PAR_XPOS] - source->pixels->col0;
+      Yo = source->modelEXT->params->data.F32[PM_PAR_YPOS] - source->pixels->row0;
+    } else {
+      Xo = source->peak->xf - source->pixels->col0;
+      Yo = source->peak->yf - source->pixels->row0;
+    }
     for (int iy = 0; iy < source->pixels->numRows; iy++) {
         for (int ix = 0; ix < source->pixels->numCols; ix++) {