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RASA 11 - center lens array (rotates)?

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9 replies to this topic

#1 Ron in Michigan

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Posted 15 August 2019 - 04:38 PM

I have a RASA 11 and have not been able to get a flat in focus field from edge to edge. After much tweaking of spacing and adding Baader UFC I now get center and left side in focus and the right side of the full frame sensor has donuts (out of focus),
When I change cameras or spacing and I rotate things on (extensions etc) the enter unit rotates.  IS this something they aligned carefully at the factory?  Or does it not matter how much it rotates?
I don't feel I should have this much problem with a 3500. scope that is designed for imaging. 

I just read a early review and the reviewer said his center lens array rotated and Celestron said to swap the scope for a new one.  Is that necessary? 

 



#2 DuncanM

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Posted 15 August 2019 - 05:14 PM

Contact Celestron.  I don't think the lens should rotate.


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#3 Benni123456

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Posted 17 August 2019 - 09:55 AM

my god 3500 dollar and then completely lousy build.

What is Celestron thinking. Just cost saving at any price.

 

I wonder who builds these scopes together. Foxcon is known to use schoolchildren who are told they do  not get their degree when they do not work. Do they have similar practices at Celestron?



#4 kingjamez

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Posted 17 August 2019 - 03:07 PM

my god 3500 dollar and then completely lousy build.
What is Celestron thinking. Just cost saving at any price.

I wonder who builds these scopes together. Foxcon is known to use schoolchildren who are told they do not get their degree when they do not work. Do they have similar practices at Celestron?


Blow things out of proportion much?

#5 Astrojedi

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Posted 19 August 2019 - 08:34 AM

I have a RASA 11 and have not been able to get a flat in focus field from edge to edge. After much tweaking of spacing and adding Baader UFC I now get center and left side in focus and the right side of the full frame sensor has donuts (out of focus),
When I change cameras or spacing and I rotate things on (extensions etc) the enter unit rotates.  IS this something they aligned carefully at the factory?  Or does it not matter how much it rotates?
I don't feel I should have this much problem with a 3500. scope that is designed for imaging. 

I just read a early review and the reviewer said his center lens array rotated and Celestron said to swap the scope for a new one.  Is that necessary? 

No the secondary assembly is not supposed to rotate. Sometimes the gasket comes lose. A rotating secondary assembly makes it almost impossible for the scope to hold optical alignment. You need to contact Celestron.



#6 Ron in Michigan

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Posted 23 August 2019 - 11:09 AM

I removed the camera train and the large ring.  I tried to rotate the corrector assembly with the camera and ring off and I could not?   
Oddly the camera train and lock down ring rotate when installed? 

Celestron finally responsed to me plea for help and is talking about returning it for repair. I bought it in Nov of 2018 and not had a flat frame yet.
But I'm close?  (Do I send it in?) Or....

Am I to picky? After almost a year of trying to tweak out a flat star field. I got my best to date... but Still not good enough for me? 

please advise that this is great or send it in.  Or try this or that? 

I pick one sub from last night. My flattest yet.  About 2mb download compressed to a jpg.  My biggest problem is on the right and lower right. 
Often upper left and lower right.

 

https://www.dropbox....GB_VNG.jpg?dl=0


Edited by Ron in Michigan, 23 August 2019 - 11:10 AM.


#7 th3r3ds0x

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Posted 23 August 2019 - 06:29 PM

I too have a rasa 11 and it’s solid.  It’s it possible you were just rotating the celestron camera adapter that is held by the knurled ring?  Sounds to me like this could be all that was rotating and if that’s the case you just need to snug it up better. Don’t go crazy though because you can loosen the assembly my mistake if you over-tighten the ring.  I hope that helps.

 

Sean



#8 f430

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Posted 24 August 2019 - 10:45 AM

There's poor stars in all the corners, and if that image is the Best you can get, I'd send the scope in for repairs!

 

You shouldn't have to fight to get round stars!

 

If you bought the scope new from a local dealer, ask/push/coerce them to ship the scope for you, or if there is a replacement warrentee. 



#9 th3r3ds0x

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Posted 24 August 2019 - 11:07 AM

Under warranty I think Celestron would provide a shipping label. Hopefully it doesn't need it but I’ve heard they have turned other RASAs around pretty quick.

#10 drone1_de

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Posted 27 August 2019 - 11:38 AM

as far as I can see I would say your scope is simply not collimated well enough, sth that you can fix on your own

Checked it?

Regards,

Lars




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