Index: /trunk/Ohana/src/relphot/src/StarOps.c
===================================================================
--- /trunk/Ohana/src/relphot/src/StarOps.c	(revision 28184)
+++ /trunk/Ohana/src/relphot/src/StarOps.c	(revision 28185)
@@ -391,4 +391,6 @@
 }
 
+# define NSIGMA_CLIP 3.0
+# define NSIGMA_REJECT 5.0
 void clean_measures (Catalog *catalog, int Ncatalog, int final) {
 
@@ -396,7 +398,8 @@
   int i, N, image_bad, TOOFEW;
   off_t *ilist;
-  double *tlist, *list, *dlist, Ns;
+  double *tlist, *list, *dlist;
   float Msys, Mcal, Mmos, Mgrid;
   StatType stats;
+  int Ncal, Nmos, Ngrid, Nfew;
 
   if (VERBOSE) fprintf (stderr, "marking poor measures\n");
@@ -416,6 +419,6 @@
   TOOFEW = MAX (5, STAR_TOOFEW);
 
-  Ns = 3;
   Ndel = Nave = 0;
+  Ncal = Nmos = Ngrid = Nfew = 0;
   for (i = 0; i < Ncatalog; i++) {
     for (j = 0; j < catalog[i].Naverage; j++) {
@@ -433,9 +436,9 @@
 	/* if (catalog[i].measure[m].dbFlags & MEAS_BAD) continue; */
 	Mcal  = getMcal  (m, i);
-	if (isnan(Mcal)) continue;
+	if (isnan(Mcal)) { Ncal ++; continue; }
 	Mmos  = getMmos  (m, i);
-	if (isnan(Mmos)) continue;
+	if (isnan(Mmos)) { Nmos ++; continue; }
 	Mgrid = getMgrid (m, i);
-	if (isnan(Mgrid)) continue;
+	if (isnan(Mgrid)) { Ngrid ++; continue; }
 
 	Msys = PhotSys (&catalog[i].measure[m], &catalog[i].average[j], &catalog[i].secfilt[j*PhotNsec]);
@@ -444,16 +447,21 @@
 	N++;
       }
-      if (N <= TOOFEW) continue;
+      if (N <= TOOFEW) { Nfew ++; continue; }
 
       /* 3-sigma clip based on stats of inner 50% */
+
+      // calculated mean of inner 50%
       initstats ("INNER_MEAN");
       liststats (list, dlist, N, &stats);
       stats.sigma = MAX (MIN_ERROR, stats.sigma); /* if measurements agree too well, sigma -> 0.0 */
+
+      // ignore entries > 3sigma from inner mean
       for (k = m = 0; k < N; k++) {
-	if (fabs (list[k] - stats.median) < Ns*stats.sigma) {
+	if (fabs (list[k] - stats.median) < NSIGMA_CLIP*stats.sigma) {
 	  list[m] = list[k];
 	  m++;
 	}
       }
+      // recalculate the mean & sigma of the accepted measurements
       initstats ("MEAN");
       liststats (list, dlist, m, &stats);
@@ -483,7 +491,7 @@
       if (N < TOOFEW) continue;
 
-      /* mark bad measures */
+      /* mark bad measures (> 3 sigma deviant) */
       for (k = 0; k < N; k++) {
-	if (fabs (list[k] - stats.median) > Ns*stats.sigma) {
+	if (fabs (list[k] - stats.median) > NSIGMA_REJECT*stats.sigma) {
 	  catalog[i].measure[ilist[k]].dbFlags |= ID_MEAS_POOR_PHOTOM;
 	  Ndel ++;