Index: trunk/psastro/src/psastroMosaicAstrom.c
===================================================================
--- trunk/psastro/src/psastroMosaicAstrom.c	(revision 10613)
+++ trunk/psastro/src/psastroMosaicAstrom.c	(revision 10815)
@@ -28,4 +28,7 @@
 
     // XXX no input distortion model yet; existing fpa distortion is identity: replace it
+    // XXX make this a test if these are NULL; the load step can NULL them if nothing is loaded
+    // XXX if we have an input distortion model, the gradient is measuring the error rel to that model
+    // XXX how does this couple to the individual chip fits?
     psFree (fpa->toTPA);
     psFree (fpa->fromTPA);