Focusing the telescope by positioning the secondary mirror.

1.  Use the handpaddle to focus the star. This is not the focusing
    of the instrument (F1 or F3), 
    but you focus the telescope by moving the secondary.
    The best focus is reached if the star is a dot. If it is a circle then
    it is way out of focus and you have the move the secondary.
2.  A better focus can be obtained by not focusing from the
    guider screen in the laser room, but going down to the 
    coude room
    * put the control on "COUDE" at the console in the doom
    * go down one floor to the COUDE room
    * move a mirror such that the light does not go
      to the guider but instead to the eyepiece
    * use the handpaddle to focus. The buttons to do so are
      on top of the handpaddle.
    * first focus the eyepiece on the list. The slit should
      be in focus. It help if you use your flashlight
      to illuminate the slit.
    * make the size of the star on the slit as small as possible
3.  go to an "atlas" window and type "focus". This will
    give you a number for the focus position.


last update: Dec 19, 1996 by ejb