diff --git a/script/optics/RefocusManipulatorScan.py b/script/optics/RefocusManipulatorScan.py
index 5e989b7a..0f717bdc 100644
--- a/script/optics/RefocusManipulatorScan.py
+++ b/script/optics/RefocusManipulatorScan.py
@@ -10,7 +10,7 @@ move manipulator and mirror to center position before start!
 import math
 
 # adjust the following parameters
-DISTANCE_X = 8. # mm
+DISTANCE_X = 6. # mm
 #DISTANCE_Ry = 0.5 # mrad (Ry)
 SLOPE = 1.0/0.24 # mm/mrad (DX / DRy)
 STEPS = 160