diff --git a/scripts/st_process_offline.sh b/scripts/st_process_offline.sh
index ffd7abf..a9fcc8b 100755
--- a/scripts/st_process_offline.sh
+++ b/scripts/st_process_offline.sh
@@ -7,7 +7,12 @@ for file in 2*.fits; do
     mv test.cat $file.cat
 
     # Run addwcs
-    addwcs -f $file -r test.fits
+    if [ -z $1 ]; then
+	addwcs -f $file -r test.fits
+    else
+        echo "Limiting magnitude of star catalog to $1"
+	addwcs -f $file -r test.fits -m $1
+    fi
 
     # Run satid
     satid $file $file.png/png 2>/dev/null 
@@ -15,3 +20,4 @@ for file in 2*.fits; do
     # Move calibrated file
     mv $file.cat $file.cal $file.id $file $file.png png/
 done
+