Index: trunk/ppImage/src/ppImageOutput.c
===================================================================
--- trunk/ppImage/src/ppImageOutput.c	(revision 6064)
+++ trunk/ppImage/src/ppImageOutput.c	(revision 6114)
@@ -4,5 +4,5 @@
 {
     const char *outname = psMetadataLookupStr(NULL, config->arguments, "-output"); // Name of output file
-    psFits *outFile = psFitsOpen(outname, "w"); // File for writing
+    psFits *outFile = psFitsOpen(outname, "a"); // File for writing
 
     // Write the output