Index: trunk/psLib/src/fits/psFits.c
===================================================================
--- trunk/psLib/src/fits/psFits.c	(revision 17641)
+++ trunk/psLib/src/fits/psFits.c	(revision 17656)
@@ -7,6 +7,6 @@
  *  @author Robert DeSonia, MHPCC
  *
- *  @version $Revision: 1.79 $ $Name: not supported by cvs2svn $
- *  @date $Date: 2008-03-14 18:24:27 $
+ *  @version $Revision: 1.80 $ $Name: not supported by cvs2svn $
+ *  @date $Date: 2008-05-13 22:03:21 $
  *
  *  Copyright 2004-2005 Maui High Performance Computing Center, University of Hawaii
@@ -603,5 +603,9 @@
 
     // if we are setting a trivial compression (NONE), don't bother with the other parameters
-    if (type == PS_FITS_COMPRESS_NONE) return true;
+    if (type == PS_FITS_COMPRESS_NONE) {
+        return true;
+    }
+
+    PS_ASSERT_VECTOR_NON_NULL(tilesize, false);
 
     // convert a psVector into the (long *) array that cfitsio requires