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Secondary returned from recoating in two pieces. What can I do?


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#1 qrjones

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Posted 17 August 2015 - 06:18 PM

I was recently given a 12" LX200 EMC with a secondary that was clearly toast. After being careful about marking it's orientation during removal, I sent it to a well known company for 98% enhanced aluminum coating.It arrived today and when I opened the box, I found that the mirror had been completely removed from the machined aluminum disc that is drilled and tapped for the collimation screws and center pivot pin. I was completely unprepared for this. The first question: Is his normal?
 
Secondly, Is this something that I might be able to repair myself?  I read one other post of a guy that seemed to be able to pull it off without special tools and such. My greatest concern(obviously) is the centering of mirror on the aluminum disc and the margin of error therein.
 
Any input would be appreciated.
 
Thanks!


#2 MistrBadgr

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Posted 18 August 2015 - 11:49 AM

Personally, I would make the attempt to put it back together myself, just making sure that I did not tear up anything.  In an older LX 200 10 inch that I worked on, I found the hole in the center of the corrector plate to be a bit off center, I think as part of the design.  If you know how that was positioned it will be a big help.  I am making a guess that the secondary mirror and its parts were centered in that hole.  I have been told that part of the assembly and collimation process includes rotating the corrector plate around until that little bit of offset matches up with the rest of the scope.

 

With the one I worked on, I did not take the secondary mirror off of the parts that were holding it, so I do not know anything about that.  You might call Meade Customer Service and see what they say.  I know they do not actively support the older LX 200 Classic scopes.  I think this is due to not making the parts for them any more.  However, for something like this, they could probably help.  There is another gentleman, Ron Sampson, that does good work and is good to work with.  The last information I have is that he can be contacted at rsampsonus@yahoo.com.

 

Hope this helps.

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#3 qrjones

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Posted 23 August 2015 - 06:40 AM

Thanks Bill.

 

I have made some real progress. I found a machine shop owned by a super nice guy into astronomy. He made a jig to align the two pieces perfectly as there is a 1/8" variance in diameter. All I need now is the 3m VHB adhesive tape I have been told is best.



#4 MistrBadgr

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Posted 23 August 2015 - 10:56 AM

Sounds like a good plan!  If you would, let us know how it works out so everyone will know.

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#5 cerickson

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Posted 25 December 2016 - 12:16 AM

Removing the secondary mirror from the holder isn't surprising.  It has to go into a coating chamber which gets put under a high vacuum and as much as possible, all additional potential sources of moisture, oils or other contamination are removed first.  Not to mention that an acid is used to remove the old mirror coating and you don't want that on your secondary cell parts.

 

I hope that helps.



#6 MistrBadgr

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Posted 25 December 2016 - 11:10 AM

Thanks, Chris!  That is good information to have in the thread!

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma




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