diff --git a/site_ansto/instrument/reflectometer/extraconfig.tcl b/site_ansto/instrument/reflectometer/extraconfig.tcl
index ec38a3a2..6b1e8cd2 100644
--- a/site_ansto/instrument/reflectometer/extraconfig.tcl
+++ b/site_ansto/instrument/reflectometer/extraconfig.tcl
@@ -17,10 +17,11 @@ slit3_distance 5600
 slit3_base 20
 
 proc set_two_theta { arg } {
+  set rad [expr ($arg/180.0)*3.1415926535897932384626433832795]
   set d1 [expr [SplitReply [detector_distance]] - [SplitReply [sample_distance]]]
   set d2 [expr [SplitReply [slit4_distance]] - [SplitReply [sample_distance]]]
-  set h1 [expr [SplitReply [detector_base]] + $d1 * tan($arg)]
-  set h2 [expr [SplitReply [slit4_base]] + $d2 * tan($arg)]
+  set h1 [expr [SplitReply [detector_base]] + $d1 * tan($rad)]
+  set h2 [expr [SplitReply [slit4_base]] + $d2 * tan($rad)]
   return "dz=$h1,st4vt=$h2"
 }
 publish set_two_theta user
@@ -28,7 +29,7 @@ publish set_two_theta user
 proc get_two_theta {} {
   set d1 [expr [SplitReply [detector_distance]] - [SplitReply [sample_distance]]]
   set h1 [expr [SplitReply [dz]] - [SplitReply [detector_base]]]
-  return [expr atan2($h1, $d1)]
+  return [expr (180.0*atan2($h1, $d1))/3.1415926535897932384626433832795]
 }
 publish get_two_theta user