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Setting up the GSO coma corrector

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#176 StarCurious

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Posted 23 September 2019 - 11:19 AM


Yes, the extenders I used all had standard 48mm threads.

John,

 

Good.

 

What is the length of the GSO CC 2" eyepiece holder, broken down as the leftmost section in the picture on Post #3?

 

EDIT: I used the picture in Post #3, I measured on screen the 19mm is 70mm long, the GSO CC 2" eyepiece holder is 175mm long. Therefore, approximately the GSO 2" eyepiece holder may be (19*175/71=) 48mm.  How far off am I?

 

MORE EDIT: Your GSO CC 2" to 1.25" adapter is 10mm high (?), With that added, the 1.25" eyepiece holder is now (10=48=) 58mm above the focuser 2" draw tube.  My set up needs to be 61mm above.  That means I need 3mm more focuser inward travel than standard set up?

Thanks,

Joseph


Edited by StarCurious, 23 September 2019 - 11:38 AM.


#177 precaud

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Posted 23 September 2019 - 11:37 AM

Joseph,

 

I don't know, I no longer have one of these CC's, mine was stolen a couple years ago. If the lens is properly placed, then what you do above it is totally up to you, as long as the spacing dimensions are satisfied, and it comes to focus.



#178 StarCurious

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Posted 23 September 2019 - 12:04 PM

John,

 

Thank you for your excellent presentations and illustrations throughout this thread.

 

Joseph



#179 Baatar

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Posted 25 October 2019 - 05:43 AM

I thought it would be useful if I include a link here to a recent thread that I started in relation to the GSO coma corrector.

 

https://www.cloudyni...extension-47mm/

 

 

Please note that this worked for me with SW 10" collapsible dob, and also for Dave with Z10 dob.


Edited by Baatar, 25 October 2019 - 05:44 AM.


#180 shubham_chandravanshi

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Posted 26 October 2020 - 02:03 PM

Hey guys, I have just ordered a GSO 8" F/4 as my first scope with an Explore Scientific Exos-2 PMC-8 WiFi Goto Mount. I am thinking to buy the GSO 2" CC with proper spacers. I read this whole thread today and I want to sincerely thank all of you guys for taking me from zero knowledge on how to use CC (I thought it was just like a barlow) to letting me feel a lot more confident about buying it and being able to use it. I will be using it for visuals as well as for AP.

I will be going the path to add the proper spacers to reach the 75mm backfocus distance and parfocalize all my 1.25" eyepieces. My main concern is with using barlows with this CC. Where do I need to put a barlow in this configuration? It would be a great help if you could help me figure this out for both 1.25" and 2" barlows.

And while I was reading this thread, near the end, I read someone addressing not to buy this CC for AP at all! Is this really true? I live in India and this is the only eyepiece at my disposal.

Thanks in advance for your help!
Clear Skies!

Edited by shubham_chandravanshi, 26 October 2020 - 02:05 PM.


#181 MellonLake

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Posted 06 November 2020 - 07:29 PM

Precaud

 

Thank you for this thread.  I just set up my new GSO coma corrector with the 19mm spacer and it went very nicely thanks to you, the XT10 telescope would not have reached focus without this spacer (even though I have a great deal of infocus). 

 

The coma corrector leads to very refractor like views (with diffraction spikes on bright stars).   It works well to clean up the coma in my F/4.7  no more comets in the outer field of view. 

 

I set up my 2" APM UFF 30mm with a parfocal ring.  The balance of my eyepieces are very close to parfocal so I don't think I have to adjust them at all (even though I have a bunch of parfocal rings on the way).

 

Thanks Again!  


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