Index: branches/pap/ppStack/src/ppStackSources.c
===================================================================
--- branches/pap/ppStack/src/ppStackSources.c	(revision 26306)
+++ branches/pap/ppStack/src/ppStackSources.c	(revision 26308)
@@ -272,4 +272,5 @@
     // Double check: all transparencies should be zero
     {
+        psVectorInit(zp, 0);            // Have corrected for airmass and exptime differences
         psArray *matches = pmSourceMatchSources(sourceLists, radius, true); // List of matches
         if (!matches) {