Index: trunk/psastro/src/psastroChipAstrom.c
===================================================================
--- trunk/psastro/src/psastroChipAstrom.c	(revision 10716)
+++ trunk/psastro/src/psastroChipAstrom.c	(revision 10785)
@@ -1,3 +1,4 @@
 # include "psastro.h"
+# define NONLIN_TOL 0.001 /* tolerance in pixels */
 
 bool psastroChipAstrom (pmConfig *config, psArray *refs) {
@@ -55,5 +56,5 @@
 		    return false;
 		}
-		pmAstromWriteWCS (updates, fpa, chip);
+		pmAstromWriteWCS (updates, fpa, chip, NONLIN_TOL);
 		psMetadataAdd (readout->analysis, PS_LIST_TAIL, "PSASTRO.HEADER",  PS_DATA_METADATA, "psastro header stats", updates);
 		psFree (updates);