Index: trunk/ppSim/src/ppSimArguments.c
===================================================================
--- trunk/ppSim/src/ppSimArguments.c	(revision 18011)
+++ trunk/ppSim/src/ppSimArguments.c	(revision 24099)
@@ -31,4 +31,5 @@
     psMetadataAddStr(arguments,  PS_LIST_TAIL, "-format", 0, "Camera format name", NULL);
     psMetadataAddStr(arguments,  PS_LIST_TAIL, "-type", 0, "Exposure type (BIAS|DARK|FLAT|OBJECT)", NULL);
+    psMetadataAddStr(arguments,  PS_LIST_TAIL, "-obs_mode", 0, "observation mode", NULL);
     psMetadataAddStr(arguments,  PS_LIST_TAIL, "-filter", 0, "Filter name", NULL);
     psMetadataAddF32(arguments,  PS_LIST_TAIL, "-exptime", 0, "Exposure time (s)", NAN);
@@ -108,4 +109,9 @@
     ppSimArgToRecipeF32(&status, options, "STARS.DENSITY", arguments, "-starsdensity");
     ppSimArgToRecipeBool(&status, options, "PHOTOM",        arguments, "+photom");
+    psString obs_mode = psMetadataLookupStr(&status, arguments, "-obs_mode");
+    if (obs_mode) {
+        psMetadataAddStr(options, PS_LIST_TAIL, "OBS_MODE", 0, "observation mode", obs_mode);
+    }
+
 
     // if we are loading the input image (not creating it), then we can skip the remaining arguments