Index: /trunk/MagicSoft/Mars/mastro/MAstroSky2Local.cc
===================================================================
--- /trunk/MagicSoft/Mars/mastro/MAstroSky2Local.cc	(revision 3534)
+++ /trunk/MagicSoft/Mars/mastro/MAstroSky2Local.cc	(revision 3535)
@@ -46,4 +46,12 @@
 //   Double_t azimuth   = v.Phi();
 //   Double_t zdistance = v.Theta();
+//
+// To get the inverse matrix for an inverse transformation you can use:
+//
+//   MAstroSky2Local::Invert()
+//
+// or simply do:
+//
+//   v *= MAstroSky2Local(time, obs).Inverse();
 //
 ////////////////////////////////////////////////////////////////////////////