Index: /trunk/Mars/mcore/ofits.h
===================================================================
--- /trunk/Mars/mcore/ofits.h	(revision 16601)
+++ /trunk/Mars/mcore/ofits.h	(revision 16602)
@@ -769,5 +769,5 @@
 
         auto ib = fOutputBuffer.begin();
-        auto ie = fOutputBuffer.end();
+        auto ie = fOutputBuffer.rbegin();
         *ib++ = 0;
         *ib++ = 0;
@@ -775,8 +775,8 @@
         *ib   = 0;
 
-        *--ie = 0;
-        *--ie = 0;
-        *--ie = 0;
-        *--ie = 0;
+        *ie++ = 0;
+        *ie++ = 0;
+        *ie++ = 0;
+        *ie   = 0;
 
         if (!byte_swap)