Index: trunk/psLib/src/fits/psFitsScale.c
===================================================================
--- trunk/psLib/src/fits/psFitsScale.c	(revision 17660)
+++ trunk/psLib/src/fits/psFitsScale.c	(revision 18156)
@@ -176,6 +176,6 @@
     PS_ASSERT_FITS_NON_NULL(fits, false);
 
-    *bscale = 1.0;
-    *bzero = 0.0;
+    *bscale = NAN;
+    *bzero = NAN;
     *blank = 0;