Index: /trunk/psphot/src/psphotDefineFiles.c
===================================================================
--- /trunk/psphot/src/psphotDefineFiles.c	(revision 13007)
+++ /trunk/psphot/src/psphotDefineFiles.c	(revision 13008)
@@ -40,4 +40,13 @@
 	if (!pmFPAfileDefineFromFPA (config, input->fpa, DX, DY, "PSPHOT.BACKMDL")) {
 	    psError(PSPHOT_ERR_CONFIG, false, "Cannot find a rule for PSPHOT.BACKMDL");
+	    return false;
+	}
+    }
+    // optionally save the background model's standard deviation (small FITS image)
+    if (psMetadataLookupBool(NULL, recipe, "SAVE.BACKMDL.STDEV")) {
+	int DX = psMetadataLookupS32 (&status, recipe, "BACKGROUND.XBIN");
+	int DY = psMetadataLookupS32 (&status, recipe, "BACKGROUND.YBIN");
+	if (!pmFPAfileDefineFromFPA (config, input->fpa, DX, DY, "PSPHOT.BACKMDL.STDEV")) {
+	    psError(PSPHOT_ERR_CONFIG, false, "Cannot find a rule for PSPHOT.BACKMDL.STDEV");
 	    return false;
 	}
Index: /trunk/psphot/src/psphotOutput.c
===================================================================
--- /trunk/psphot/src/psphotOutput.c	(revision 13007)
+++ /trunk/psphot/src/psphotOutput.c	(revision 13008)
@@ -1,5 +1,8 @@
 # include "psphotInternal.h"
 
-pmReadout *psphotSelectBackground (pmConfig *config, pmFPAview *view) {
+pmReadout *psphotSelectBackground (pmConfig *config,
+				   pmFPAview *view,
+				   const bool stdev // return background's standard deviation?
+				   ) {
 
     bool status;
Index: /trunk/psphot/src/psphotReadoutCleanup.c
===================================================================
--- /trunk/psphot/src/psphotReadoutCleanup.c	(revision 13007)
+++ /trunk/psphot/src/psphotReadoutCleanup.c	(revision 13008)
@@ -45,4 +45,5 @@
     // remove internal pmFPAfiles, if created
     pmFPAfileDropInternal (config->files, "PSPHOT.BACKMDL");
+    pmFPAfileDropInternal (config->files, "PSPHOT.BACKMDL.STDEV");
     pmFPAfileDropInternal (config->files, "PSPHOT.BACKGND");