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What is replaced in a SCT with the factory upgrade Meade now offers

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15 replies to this topic

#1 12BH7

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Posted 23 June 2022 - 09:07 AM

I've emailed Meade a number of times and they FINALLY said that they can do an upgrade on my 8" EMC SCT. But I couldn't find out exactly what they DO when they upgrade it. 

 

What I am trying to find out is what do they replace when they do the upgrade. From what I've read it's the corrector plate and primary mirror. 

 

Do they also replace the secondary? 

 

Do they recollimate it before sending it back?

 

Is it worth doing over buying a new ACF OTC?

 

Thanks

Charles



#2 carolinaskies

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Posted 23 June 2022 - 04:46 PM

All optics/internal components are replaced and collimated.  Consider what a new OTA of your size costs...  You'll be happy with the new optics.  



#3 12BH7

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Posted 23 June 2022 - 09:20 PM

All optics/internal components are replaced and collimated.  Consider what a new OTA of your size costs...  You'll be happy with the new optics.  

I'm assuming that includes the secondary?

 

Seems Meade is keeping that one a secret



#4 carolinaskies

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Posted 24 June 2022 - 05:01 AM

What part of "all optics" do you think precludes the secondary?

It would do no good to replace a primary and corrector but not the secondary since all three are a matched system.
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#5 n2dpsky

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Posted 24 June 2022 - 10:20 AM

All SC/ACF optics produced by Meade are assembled into a matched set.   When the optics are replaced, the entire set is replaced, meaning primary, secondary and CP.    This is done for several reasons, but the main one is that nearly all optical elements have some aberrations albeit minor ones.  By matching you can have a corrector plate with a particular issue that nulls another on the primary and together they work perfectly.  Others just won't. The optics lab tests them as a set and sets them aside for final assembly.

 

Hope this helps.

 

(BTW, I was a VP at Meade)  


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#6 n2dpsky

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Posted 24 June 2022 - 10:24 AM

What part of "all optics" do you think precludes the secondary?

It would do no good to replace a primary and corrector but not the secondary since all three are a matched system.

It can be done, but it's just labor intensive to test various primary mirrors or CPs to match the secondary.   The SCOTA room doesn't want to run around and find a single mirror that matches.  They just grab a set off the shelf, unwrap, assemble, throw it on the double-pass to collimate and send it to QA.  


Edited by n2dpsky, 24 June 2022 - 10:25 AM.


#7 12BH7

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Posted 25 June 2022 - 09:45 AM

What part of "all optics" do you think precludes the secondary?

It would do no good to replace a primary and corrector but not the secondary since all three are a matched system

Too many times I've read, "replaced CP and primary". No mention of secondary and Meade's email help line was of little help. Nice guy's but they really don't actually READ the email question.



#8 carolinaskies

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Posted 25 June 2022 - 05:02 PM

Too many times I've read, "replaced CP and primary". No mention of secondary and Meade's email help line was of little help. Nice guy's but they really don't actually READ the email question.

Unlike a newtonian the secondary mirror of an SCT is not flat nor is it 'universal'.  This trait means the manufacturer is well aware of this fact and isn't going to only replace the other two components and leave an unmatched secondary in place like some shade tree mechanic 'rebuilding' an engine.  

Several of us have now told you they replace the entire set, so the question is answered. 
Time to either decide to send in the OTA or not.  

If they made an F/6.3 ACF I'd send in my classic LX200 8" and have it upgraded to ACF



#9 Bob White

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Posted 25 June 2022 - 05:33 PM

So this is an interesting topic.  What exactly is the upgrade?

I have an LX200 14" GPS and they will upgrade it to ACF?
Wonder how much that is?

 

 

Thanks,

Bob



#10 slovell1

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Posted 25 June 2022 - 06:59 PM

So this is an interesting topic.  What exactly is the upgrade?

I have an LX200 14" GPS and they will upgrade it to ACF?
Wonder how much that is?

 

 

Thanks,

Bob

I'd be interested myself to know the ballpark cost of having this upgrade done to my 10" LX200 EMC. There's nothing really wrong with it per se but the optics aqre getting some age on them.
Sam



#11 12BH7

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Posted 26 June 2022 - 10:35 AM

So this is an interesting topic.  What exactly is the upgrade?

I have an LX200 14" GPS and they will upgrade it to ACF?
Wonder how much that is?

 

 

Thanks,

Bob

Call or email. They do reply to their emails and they are very helpful.



#12 12BH7

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Posted 26 June 2022 - 10:36 AM

I'd be interested myself to know the ballpark cost of having this upgrade done to my 10" LX200 EMC. There's nothing really wrong with it per se but the optics aqre getting some age on them.
Sam

I was quoted at about $750 for my 8". 



#13 slovell1

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Posted 26 June 2022 - 12:24 PM

I was quoted at about $750 for my 8". 

12BH7's are great tubes along with 12AX7's and 12AU7's. cool.gif 
Thanks for the reply.
Regards,
Sam



#14 CltFlyboy

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Posted Yesterday, 07:54 AM

I wonder if they'd upgrade my old 2120 10"... I should call and ask, that would be a great way to breathe new life into that old beast.



#15 tim53

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Posted Yesterday, 01:29 PM

I probably know the answer to this question before I ask:  

 

would they sell an optics set to an ATM?  It might be nice to design an ota using carbon fiber to reduce thermal effects on focus, and a fixed primary to secondary separation with a high quality focuser on the back to prevent mirror shift. 
 

tim



#16 carolinaskies

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Posted Yesterday, 04:42 PM

I probably know the answer to this question before I ask:  

 

would they sell an optics set to an ATM?  It might be nice to design an ota using carbon fiber to reduce thermal effects on focus, and a fixed primary to secondary separation with a high quality focuser on the back to prevent mirror shift. 
 

tim

I don't believe they've ever sold sets like that.  




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