Index: trunk/psastro/src/psastroMosaicOneChip.c
===================================================================
--- trunk/psastro/src/psastroMosaicOneChip.c	(revision 41895)
+++ trunk/psastro/src/psastroMosaicOneChip.c	(revision 42289)
@@ -148,4 +148,7 @@
     if (order == 1) { minNstar = PS_MAX ( 8, minNstar); }
 
+    // determine fromFPA transformation and apply new transformation to raw & ref stars
+    psastroUpdateChipToFPA (fpa, chip);
+
     bool validSolution = true;
 
@@ -162,4 +165,8 @@
     if (astNstar < minNstar) {
         psLogMsg("psastro", PS_LOG_INFO, "solution uses too few stars: %d < %d", astNstar, minNstar);
+        validSolution = false;
+    }
+    if (!chip->fromFPA) {
+        psLogMsg("psastro", PS_LOG_INFO, "toFPA/fromFPA inversion failure");
         validSolution = false;
     }
@@ -189,8 +196,5 @@
     psMetadataAddF32 (updates, PS_LIST_TAIL, "AST_MRY",   PS_META_REPLACE, "mosaic astrometry Y 10-90 percentile (arcsec)", results->dYrange * plateScale);
 
-    // determine fromFPA transformation and apply new transformation to raw & ref stars
-    psastroUpdateChipToFPA (fpa, chip);
-
-    //plot results
+    // plot results
     pmAstromVisualPlotMosaicOneChip(rawstars, refstars, match, recipe);