Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Celestron C8 Visual Back Options

  • Please log in to reply
3 replies to this topic

#1 engrdy

engrdy

    Lift Off

  • -----
  • topic starter
  • Posts: 2
  • Joined: 26 Jul 2019

Posted 17 November 2019 - 08:00 PM

I currently have a Celestron C8 (the orange tube that comes with the NexStar, purchased about 2014) with a 1.25" Visual Back on an AVX.

I'm trying to dabble in AP (I understand the C8 isn't ideal but its what I have at the moment), the problem is i get heavy vignetting with a 1.25" adaprter attached to a T-Ring and a .63 Focal reducer on the Nikon D5300. I read that converting to a 2" Visual Back will eliminate vignetting. Now here's my problem.

Celestrons 2" T-Adapter will only allow me to attach my Camera. I cant quickly change to using my 1.25" EP's for visual and no way to attach 2" filters if i ever go that direction. And price is about $37 with shipping where im from.

I found an alternative. This 2" Mount Adapter (which claims it will fit most modern SCT's) coupled with this thing that attaches to the T-Ring, which will allow me to slide the camera into the mount adapter and also allow mounting 2" filters. With a 2" to 1.25" mount adapter i can still easily use my EP's without having to change Visual Backs every time. The three items will only set me back about $26.

Over all, im leaning towards the 2nd option as it allows me more flexibility and at a cheaper price too. But i just need your opinion on the following.

How likely is the 2" Mount Adapter (2nd option) going to fit my C8 SCT? And what do you think the vignetting will be like? Will it have similar if not equal results in terms of vignetting if i got the Celestron 2" Adapter?



#2 jerobe

jerobe

    Ranger 4

  • -----
  • Posts: 307
  • Joined: 08 Dec 2017
  • Loc: Southeast Texas

Posted 17 November 2019 - 09:56 PM

Have you looked through the items that Scopestuff sells? They have all kinds of adapters.

 

http://www.scopestuff.com



#3 Eddgie

Eddgie

    ISS

  • *****
  • Posts: 25012
  • Joined: 01 Feb 2006

Posted 18 November 2019 - 10:14 AM

I would guess that it would fit. It says SCT thread and that is a well known thread size and few things use a visual back like this other than SCTs and lately some MCTs.  

 

And yes, the 2" visual back is a very flexible solution because it does allow you to use a 2" diagonal.

 

Now if you are planning on using the reducer, you still might get some vignetting, but getting rid of the 1.25" visual back will greatly improve the size of your fully illuminated circle, but this circle itself is not all that big on the C8 when a reducer is used, but the improvement will be quite substantial. 



#4 engrdy

engrdy

    Lift Off

  • -----
  • topic starter
  • Posts: 2
  • Joined: 26 Jul 2019

Posted 18 November 2019 - 07:19 PM

Have you looked through the items that Scopestuff sells? They have all kinds of adapters.

 

http://www.scopestuff.com

Thanks for the other options. Unfortunately the site seems more targeted towards the US. And I am halfway across the globe. Buying from China seems like a smarter and more economic option. Especially considering most of the items on that site are probably just rebranded chinese products. But still, thank you for the link!
 

I would guess that it would fit. It says SCT thread and that is a well known thread size and few things use a visual back like this other than SCTs and lately some MCTs.  

 

And yes, the 2" visual back is a very flexible solution because it does allow you to use a 2" diagonal.

 

Now if you are planning on using the reducer, you still might get some vignetting, but getting rid of the 1.25" visual back will greatly improve the size of your fully illuminated circle, but this circle itself is not all that big on the C8 when a reducer is used, but the improvement will be quite substantial. 

Thanks for the input! I guess im going for it then. Fingers crossed it actually works and helps with my vignetting problem.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics