Index: trunk/Ohana/src/libdvo/include/dvo.h
===================================================================
--- trunk/Ohana/src/libdvo/include/dvo.h	(revision 8429)
+++ trunk/Ohana/src/libdvo/include/dvo.h	(revision 8521)
@@ -107,4 +107,7 @@
   int    swapped;       /* is table in internal byte-order? */
 } FITS_DB;
+
+/* the basic HST GSC layout corresponds to a depth of 3 */
+# define SKY_DEPTH_HST 3
 
 /* SkyRegion : better implementation than GSCRegion */