Index: trunk/psphot/src/psphotStackChisqImage.c
===================================================================
--- trunk/psphot/src/psphotStackChisqImage.c	(revision 31154)
+++ trunk/psphot/src/psphotStackChisqImage.c	(revision 32695)
@@ -13,4 +13,6 @@
     psAssert (chisqFile, "missing chisq image FPA?");
 
+    // the readout containing the chisq image is generated in the first pass of this loop and
+    // used by the successive passes
     pmReadout *chiReadout = NULL;