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2-inch XLT Diagonal (SCT)

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#1 PatDunne


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Posted 23 July 2012 - 05:14 PM

Hi All,
I bought a Celestron 2-inch XLT Diagonal, but I am really disappointed that the fit on to the rear cell of the scope is very poor. I have found that the only way to make it fit properly is to fit a plastic spacer peice into the threaded sleeve that goes on to the end cell of the scope.

Has anyone else found this or is the fit usually good and tight?

#2 herrointment


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Posted 23 July 2012 - 05:52 PM

I've got one. No problems getting it tight although it gets tight "quick".....there's no feel to it at all.

Down the road a ways it'll be replaced.

#3 Gastrol



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Posted 23 July 2012 - 05:59 PM

Originally, when I had a 9.25 the threading action of the diagonal felt somewhat 'crude' and rough for me so I applied a very tiny amount of grease on the threads. The nose of the diagonal should butt up squarely against the rear cell without having to use a spacer of some sort.

#4 Doc Bob

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Posted 23 July 2012 - 08:29 PM

I prefer using refractor diagonals for the same reason cited. I purchased this adaptor from Astro Physics:

2" Adapter with Brass Locking Ring and 3 Large Thumbscrews - for larger SCTs with 3.25" Rear Cell, (ADASCTLC and ADASCTLM).

I'm not sure if the CPC 9.25 has a 3.25" rear cell . . . but there are smaller adaptors that will fit. With this thing I have not had any problems with diagonals loosening, rotating, or otherwise ill-fitting; and I can use my diagonal(s) in all of my scopes.


#5 PatDunne


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Posted 26 July 2012 - 06:24 PM

Many thanks for the replies folks.

It would appear that Celestron have made a bit of a lemon. Will try the grease trick and I might fit a slim rubber oring, as I am not to keen on a direct metal to metal fit.

#6 rookie


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Posted 26 July 2012 - 10:15 PM

Don't force it and strip the threads.

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