Index: trunk/psModules/src/concepts/pmConceptsAverage.c
===================================================================
--- trunk/psModules/src/concepts/pmConceptsAverage.c	(revision 22706)
+++ trunk/psModules/src/concepts/pmConceptsAverage.c	(revision 26964)
@@ -36,4 +36,5 @@
 
     double time      = 0.0;             // Time of observation
+    double zp        = 0.0;             // Zero point
     psTimeType timeSys = 0;             // Time system
     char *filter     = NULL;            // Filter
@@ -63,4 +64,7 @@
         psTimeConvert(fpaTime, PS_TIME_TAI);
         time       += psTimeToMJD(fpaTime);
+
+        zp += psMetadataLookupF32(NULL, fpa->concepts, "FPA.ZP");
+
         if (num == 1) {
             timeSys = psMetadataLookupS32(NULL, fpa->concepts, "FPA.TIMESYS");
@@ -85,4 +89,5 @@
 
     time /= (double)num;
+    zp /= (double)num;
 
     MD_UPDATE(target->concepts, "FPA.TIMESYS", S32, timeSys);
@@ -92,4 +97,5 @@
     MD_UPDATE_STR(target->concepts, "FPA.INSTRUMENT", instrument);
     MD_UPDATE_STR(target->concepts, "FPA.DETECTOR", detector);
+    MD_UPDATE(target->concepts, "FPA.ZP", F32, zp);
 
     // FPA.TIME needs special care