Index: trunk/Ohana/src/addstar/include/addstar.h
===================================================================
--- trunk/Ohana/src/addstar/include/addstar.h	(revision 39024)
+++ trunk/Ohana/src/addstar/include/addstar.h	(revision 39041)
@@ -131,4 +131,5 @@
 
 char    ZERO_POINT_OPTION[64];
+char    ZERO_POINT_KEYWORD[64];
 float	ZERO_POINT_OFFSET;
 float	ZERO_POINT_ERROR;
Index: trunk/Ohana/src/addstar/src/ConfigInit.c
===================================================================
--- trunk/Ohana/src/addstar/src/ConfigInit.c	(revision 39024)
+++ trunk/Ohana/src/addstar/src/ConfigInit.c	(revision 39041)
@@ -105,4 +105,8 @@
   if (!ScanConfig (config, "ZERO_POINT_OPTION", "%s",  0, ZERO_POINT_OPTION)) {
       strcpy (ZERO_POINT_OPTION, "NOMINAL"); 
+  }
+  // if this config variable is not set, do not set any zero point offset
+  if (!ScanConfig (config, "ZERO_POINT_KEYWORD", "%s",  0, ZERO_POINT_KEYWORD)) {
+      strcpy (ZERO_POINT_KEYWORD, "ZPT_OBS"); 
   }
 
Index: trunk/Ohana/src/addstar/src/GetZeroPointExposure.c
===================================================================
--- trunk/Ohana/src/addstar/src/GetZeroPointExposure.c	(revision 39024)
+++ trunk/Ohana/src/addstar/src/GetZeroPointExposure.c	(revision 39041)
@@ -53,5 +53,5 @@
 	    Nhead = headerSets[i].extnum_head;
 
-	    if (!gfits_scan (headers[Nhead], "ZPT_OBS", "%f", 1, &ZPT_OBS)) {
+	    if (!gfits_scan (headers[Nhead], ZERO_POINT_KEYWORD, "%f", 1, &ZPT_OBS)) {
 		fprintf (stderr, "zero point not supplied in header\n");
 		continue;
@@ -113,5 +113,5 @@
 	    
             float ZPT_OBS, ZPT_ERR;
-	    if (!gfits_scan (headers[Nhead], "ZPT_OBS", "%f", 1, &ZPT_OBS)) {
+	    if (!gfits_scan (headers[Nhead], ZERO_POINT_KEYWORD, "%f", 1, &ZPT_OBS)) {
 		fprintf (stderr, "WARNING: zero point is not measured, no valid entries in headers\n");
 		return (FALSE);
Index: trunk/Ohana/src/addstar/src/ReadImageHeader.c
===================================================================
--- trunk/Ohana/src/addstar/src/ReadImageHeader.c	(revision 39024)
+++ trunk/Ohana/src/addstar/src/ReadImageHeader.c	(revision 39041)
@@ -237,5 +237,5 @@
   if (!strcasecmp(ZERO_POINT_OPTION, "CHIP_HEADER")) {
       float ZPT_OBS;
-      if (!photcodeData || !gfits_scan (header, "ZPT_OBS", "%f", 1, &ZPT_OBS)) {
+      if (!photcodeData || !gfits_scan (header, ZERO_POINT_KEYWORD, "%f", 1, &ZPT_OBS)) {
           fprintf (stderr, "zero point not supplied in header\n");
           ZERO_POINT_OFFSET = 0.0;