Index: /trunk/ppMops/src/ppMops.c
===================================================================
--- /trunk/ppMops/src/ppMops.c	(revision 24324)
+++ /trunk/ppMops/src/ppMops.c	(revision 24325)
@@ -43,4 +43,11 @@
             exit(PS_EXIT_DATA_ERROR);
         }
+    }
+
+    // Correct ZP for exposure time
+    data->zp += 2.5 * log10(psMetadataLookupF32(NULL, header, "EXPTIME"));
+    if (!isfinite(data->zp)) {
+        psErrorStackPrint(stderr, "Zero point is unknown\n");
+        exit(PS_EXIT_CONFIG_ERROR);
     }