Installation Instructions – Celestron 11” Telescopes
Important:
removing the original focus assembly. If the telescope is not horizontal the primary
mirror could move during the installation.
Required Tools: Phillips Screwdriver
The telescope optical tube must be positioned horizontally before
1/16” Hex-Head Wrench (Not required for NexStar 11 GPS)
Step 1
NexStar 11 GPS telescopes have a rubber knob which can be pulled off. Older 11"
telescopes will have a metal focus knob which must be removed using a 1/16” hex-head
wrench to loosen a small set screw. Once the knob is removed you will see the brass
focus shaft as shown below.
Remove Focus Knob
Step 2
Turn the brass focus shaft clockwise to bring the mirror back and expose the Phillipshead screw at the end of the threaded focus rod.
Move Primary Mirror Back
Step 3
Use screwdriver to remove the small Phillips screw from the end of the threaded focus
rod.
Remove Set Screw
Step 4
Use screwdriver to remove three screws from the focus assembly cover plate (the three
screws around the outside of the focus shaft). Remove the cover plate. Hang on to the
three Phillips screws as they will be used to attach the SCT MicroFocuser.
Remove Focus Assembly Cover Plate
Step 5
Turn the brass focus shaft counterclockwise to remove it from the threaded focus rod.
This will take quite a few turns. Once the bearing assembly is removed, only the
threaded focus rod (which pushes and pulls on the mirror cell to focus the telescope) will
be left sticking out of the telescope as below.
Remove Focus Bearing Assembly
Step 6
Begin threading the SCT MicroFocuser onto the threaded focus rod.
Thread on SCT MicroFocuser
When there is only about 1/4" left to go, simply push the focuser the rest of the way in.
This will take up some of the change in focus from when you removed the original
focuser, making it quicker to return to focus the first time you use your telescope after the
SCT MicroFocuser installation.
Step 7
Use the three original Phillips screws to attach the SCT MicroFocuser to the telescope.
You are now ready to head out under the stars!
Attach the SCT Micro Focuser
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