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Orange C8

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#1 Frank Torre

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Posted 30 May 2023 - 05:56 AM

Hello all. I have 6 - 7 scope of various "flavors" up to a C11 Edge HD, which by no means makes me an expert but I can stumble my way around.

 

I was just gifted a circa 1975 orange C8.

 

I would imagine it does not have a corrector plate but just an optical glass "front."

 

Am I correct? (no pun intended).

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#2 Jim Davis

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Posted 30 May 2023 - 06:13 AM

It should have a corrector plate. Otherwise the design wouldn't work. Having recently cracked the corrector on a vintage 14" Celestron orange tube, I know how much it costs to replace it. Which we haven't done yet.



#3 Frank Torre

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Posted 30 May 2023 - 06:23 AM

I figured that, or so I thought. What threw me was the orange C8 corrector appears to be flat. My new C11 HD has "shape" to it.

 

I'm only an Electrical Engineer, I never really delved into Optics.

 

The Mak vs SCT design I do however have a little bit of a grasp on.

 

Thank you.



#4 D_talley

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Posted 30 May 2023 - 08:31 AM

You may not know the history of the scope. We have had a couple of people on CN who have replaced the corrector on their scope with glass after breaking it. Of course it did not work but they assumed the corrector was just flat glass. Give the scope a quick star test to be sure. 



#5 DAVIDG

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Posted 30 May 2023 - 09:11 AM

 A star test will easily show if it's a Schmidt corrector or a piece of flat glass.  Another method is to remove the retainer ring for the corrector and look along the edge. There should be a number engraved in it .

 

                 - Dave 



#6 dnrmilspec

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Posted 30 May 2023 - 09:15 AM

You may not know the history of the scope. We have had a couple of people on CN who have replaced the corrector on their scope with glass after breaking it. Of course it did not work but they assumed the corrector was just flat glass. Give the scope a quick star test to be sure. 

Really?  This is a problem?  Lord.  Another thing to worry about.shocked.gif



#7 D_talley

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Posted 30 May 2023 - 11:17 AM

Most people don't know how telescopes work, that is why you see them upside down in videos and in ads.  A casual look at a corrector does not reveal that it is a lens.  The OP is smart to ask about it. 

The worse I have seen was a C14 for sale on eBay. The corrector and secondary mirror were missing, my guess is the scope was dropped at one time. The "scope" was under auction with a lot of people bidding for it, the bids were in the thousands. None of the bidders knew that this scope was missing two of the three optics needed for it to work. It would work better as a trash can.  Sad. 


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#8 jgraham

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Posted 02 June 2023 - 10:26 AM

The corrector on the older Celestrons were relatively thin so they may look like flat panes of glass. But nope, there are indeed corrector plates.


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