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C14 primary mirror

Started by brewtes, 02/04/2011 01:13PM
Posted 02/04/2011 01:13PM Opening Post
Help! I have a c14 and the primary mirror is not aimed with the baffle tube. Has anyone had this problem? Has anyone ever removed the primary mirror from the base to shim it? Celestron wants a lot of money to fix their assembly mistake since it's out of warranty. Jim
Posted 02/05/2011 06:17AM #1
Jim,

This is beyond the usual repair I think. If it is out of whack, that means that the epoxy they use to cement it down has failed in some way. My understanding also is that it is difficult to recement this and align it properly w/o the right tools or equipment.

Peter
Posted 02/05/2011 07:25AM #2
James Lynch said:

Help! I have a c14 and the primary mirror is not aimed with the baffle tube. Has anyone had this problem? Has anyone ever removed the primary mirror from the base to shim it? Celestron wants a lot of money to fix their assembly mistake since it's out of warranty. Jim

In what way is it not "aimed with the baffle tube"? At any rate, forget shimming it. The primary is precisely RTVed into its fixture with a special jig. Bite the bullet and let C. fix it.

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Posted 02/05/2011 10:15AM #3
This sounds like the threaded retainer ring has come loose and the mirror is sagging. I have had C8's and C11's apart but not a C14, but I would think the design is the same. Neither of them had any shims. The primary just sat squarely in the mounting and held in place by the retainer. They did have some silicone to keep it centered, but that's it. I'm sure someone has had a C14 apart and can verify the procedure.

James Lynch said:

Help! I have a c14 and the primary mirror is not aimed with the baffle tube. Has anyone had this problem? Has anyone ever removed the primary mirror from the base to shim it? Celestron wants a lot of money to fix their assembly mistake since it's out of warranty. Jim
Posted 02/09/2011 07:44PM #4
When you say the primary is out of line are you sure it's not the secondary,on the secondary and the primary there is an orientation mark and a number that lines up the primary and secondary at the factory,you could think of it as matching I guess.I just finished dismantling a C14 and I noticed this marking on the secondary and when I dismantled the primary the orientation was also marked.In my case it was ' X618 " with an arrow to the outer edge,same on the secondary. If I remember well you can see the end of the marking on the edge of the mirror on both mirrors.I do think they lined up.NOT 100 % SURE ON THAT( can't visualize it from memory )
Just wondering did you spin the secondary around when Hyperstaring or when cleaning the secondary if you removed it from the holder.
There is no way to shim the back side of the primary and it's mounted pretty tightly to the center light return tube.But that said you could open the OTA and with white dust free gloves move the primary to see if there is any freeplay at the center tube when you rock the primary east /west or north / south.I would be very surprised if it had freeplay but everything is possible.