Below is one possible way to remove and re-install a Meade secondary.


Removal
Place two stacks of books on the table and lay a clean towel over them.
Obtain a small hex wrench ( Allen wrench ).
Make an index mark with a black marking pen if desired.
Remove the screws from the correcting plate retaining ring.
With a clean towel place the correcting plate with the secondary mirror facing down between the books.
Cover the tube with foil or plastic wrap.
Remove the three secondary adjustment screws.  The secondary will fall onto the towel.
Wrap the secondary in a small clean towel for shipment via U S Mail.
Retain the parts for reinstallation.


Reinstallation
The tricky part of re-installation is reinstalling the secondary in its well without touching the 
       easily damaged new coating.
If possible find someone with steady hands to help.  
And you will need a small mirror, possibly a mechanics adjustable mirror and a clean 'Q' tip.
Holding the correcting plate and the secondary with clean towels insert the secondary sideways
       back against its center fulcrum pin.  Then tilt the plate so the secondary is facing up.
One hex screw should be on the long end of the hex wrench.
Have your helper hold the correcting plate with the clean towel and gently rotate the secondary
       on its fulcrum pin using the 'Q' tip.   Looking in the mirror on the table watch through one
       of the adjustment screw holes until the tapped hole in the secondary plate lines up.  
       Then start the first screw.
The remaining two screws are then relatively easy.
Re-install the correcting plate into the telescope with the index marks aligned, if present.
Remove eyepiece and right angle adapter from tube bottom if present.
Put a solid color towel over the top of the tube with a light behind it and look into the bottom of the tube.
When you are relaxed and have some time adjust the three adjustment screws until when looking through
the center of the bottom of the tube all the mirrors and reflections of mirrors appear to be concentric.
To get the adjustment screws snug with the optics in alignment will take some patience.
While doing the adjustment be sure not to loosen the adjustment screws too far or the secondary will fall onto the primary.

 

Re-attaching secondary to backing plate

We no longer remove the secondary from the aluminum back plate during re-coating unless there is some unusual reason for doing so.

If a mirror is attached to a metal back plate the adhesive can be softened by soaking overnight in regular paint thinner.  Then slip the edge of a utility knife blade between mirror and back plate to gently separate them.  If using 'Silicone I' you can probably cut the sealant without soaking.  Or otherwise slip the blade of a hacksaw between mirror and wood back plate to saw the sealant.  Keep metal tools away from the mirror face.


De-coating without separating the diagonal is often possible.

de-coating an attached diagonal
 









 

 


When gluing mirrors to their mirror cell be sure to allow the sealant to cure overnight.
More info

 

Update, February 02, 2012

 

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