Index: trunk/psModules/src/objects/models/pmModel_SERSIC.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_SERSIC.c	(revision 33340)
+++ trunk/psModules/src/objects/models/pmModel_SERSIC.c	(revision 33409)
@@ -192,4 +192,10 @@
     psF32 z0 = PAR[PM_PAR_I0]*f1;
     psF32 f0 = PAR[PM_PAR_SKY] + z0;
+
+    if (!isfinite(z0)) {
+        fprintf(stderr, "z0 is not finite for %f %f %f %f %f.  Parameters: \n", X, Y, radius, z, f1);
+        fprintf(stderr, "%f %f %f %f %f %f %f %f\n", PAR[0], PAR[1], PAR[2], PAR[3], PAR[4],
+            PAR[5], PAR[6], PAR[7]);
+    }
 
     assert (isfinite(f2));