Guiding on a C8 SCT

[mikeyj1]

Hi, I want to try to image a few things with the C8 SCT, and was wondering about guiding it.  My ASi-071mcpro has an OAG, which I guess would be the best option, but its a 2" nosepiece, a it bigger than the visual back on the scope.  Does anyone mount the normal 'finder guider' on an SCT, and if so, how do you go about it...?

thanks

Mike

[catburglar]

Does your OAG have a T-thread? You could get an SCT-T mount visual back, or alternatively a 2inch visual back like this: https://www.firstlightoptics.com/adapters/baader-click-lock-2-for-celestron-meade-sct.html

[jacko61]

I've been guiding my C8 with a standard guidescope set up since I started taking astrophotography more seriously. Right from the start I've been getting good results. Guidescope is an SVBONY 60mm and I replaced the standard rings and clamps with ADM which hold the scope really solidly. 

Graeme

 

[mikeyj1]

1 hour ago, jacko61 said:

I've been guiding my C8 with a standard guidescope set up since I started taking astrophotography more seriously. Right from the start I've been getting good results. Guidescope is an SVBONY 60mm and I replaced the standard rings and clamps with ADM which hold the scope really solidly. 

Graeme

 

Looking at your picture, i see the 5" of back focus is done with an adapter.  Its a similar setup to mine, with the filter drawer, i just have the OAG in front of that, so could potentially use the OAG arrangement.  Any details on the adapters used?  Also, I'm not sure how your guide scope is attached, can you explain?

thanks

Mike

[jacko61]

I have the celestron 50mm T adapter behind the 6.3 reducer. Then  the 16.5mm zwo m42/m48 extension, then the 21mm Zwo filter drawer, finally the camera with it's 11mm m42 extension (this plus the 6.5mm from the front of the camera to the sensor makes up 105mm).  The only problem with this set up is that the filter drawer is M48 at the scope end, the 16.5 is M42 / M48 and the celestron T extension is m42 so the setup needs three m42/m48 adapter rings - 2 at the 16.5mm m48 end and one at the 16.5mm M42 end (where the filter drawer screws on). 

My C8 is on a Losmandy plate for the mount. Opposite that I have an ADM mini dovetail bar and rings for the 60mm guidescope. ADM Mini Dovetail & Guidescope Rings C8 Kit | First Light Optics  - a bit pricey but that's astrophotography !  

There's also a couple of extra brackets for a RACI and a normal finderscope but I need to move those as they interfere with the EQ8Rpro saddle. 

Graeme

Edit: - If you have the zwo OAG that's only 16.5mm so you'd have to use the 21mm extension tube. Figuring out where the various thread sizes are different and what adpters you'll need is the tricky bit. You might only need one between the OAG and the 21mm extension.

 

Edited February 10, 2022 by jacko61