Index: trunk/psastro/src/psastroMosaicAstrom.c
===================================================================
--- trunk/psastro/src/psastroMosaicAstrom.c	(revision 41499)
+++ trunk/psastro/src/psastroMosaicAstrom.c	(revision 41536)
@@ -296,9 +296,7 @@
     psRegion fitRegion = psRegionSet (xMin, xMax, yMin, yMax);
 
-    // psPlaneTransformInvert will generate a new fromTPA with order to match toTPA
+    // psPlaneTransformInvert will generate a new fromTPA (order increased vs toTPA)
     psFree (fpa->fromTPA);
-    psPlaneTransform *myPT = psPlaneTransformAlloc(fpa->toTPA->x->nX+4, fpa->toTPA->x->nY+4);
-    fpa->fromTPA = psPlaneTransformInvert (myPT, fpa->toTPA, fitRegion, 100);
-    psFree (myPT);
+    fpa->fromTPA = psPlaneTransformInvert (NULL, fpa->toTPA, fitRegion, 100, 4);
 
     psFree (fpa->toSky);