Questions re: Celestron C80ED, Canon XSi and Using 2" Barlow (1 Viewer)

I have a C80ED, Canon XSi and currently have them connected with a 1.25" adapter, barlow and a T-mount. With this arrangement I am generally happy but have experienced some vignetting.

Is it preferable to use a 2" adapter and 2" barlow, and is there a T-mount that accepts the 2" adapter?

Hope I've asked these questions intelligibly. Thanks for any information and suggestions!

http://www.telescopeadapters.com/

here you have different options to choose what suits you.

You can remove the 1.25" adapter from the T-ring and get a 2" one. I have both for my T-ring. Search for 2" T-adapter, sometimes they are called 2" T-thread camera adapter or 2" prime focus adapter for t-ring. Here's a few links to places selling them for the T-ring, first link was the cheapest I found.

http://www.optcorp.com/os-a2t-2inch-to-t-thread-adapter.html

http://www.telescopes.com/telescope-accessories/adapters/nosepiece2incht2.cfm

https://www.astronomics.com/astro-tech-2-inch-prime-focus-adapter_p17013.aspx

The other option is the one piece design as per cango's post. These are more expensive but you get peace of mind that there's no screws to come loose as you get with a T-ring. You can of course use something like loctite on the three screws on the T-ring to stop them from coming loose over time.

There's a nice 1 piece version here which is better value at $20 cheaper than the ultrawide and it offers the same amount of extra aperture. A standard 2" T-ring version wont vignette though so the only reason to go the 1 piece route is because it wont come loose.

http://agenaastro.com/blue-fireball-elim-t-2-prime-focus-adapter-canon-eos.html

Paul.

Hi,

I would use a Televue 2" Powermate its T-ring adapter and a Televue 2" Camera adapter. If I remeber correctly the c80ed has a 2" focuser? Plus you may need extension tubes depending on the distances you are shooting.
http://www.adorama.com/TVCA.html?KBID=67694
http://www.adorama.com/TVPTR.html?KBID=67694
http://www.adorama.com/TVBL2XP.html?KBID=67694

I hope this helps you. I image with a TV85 all the time.

Mike

Thanks for your comments and valuable links, cango, Paul and Mike. I'm investigating them and feel confident a solution is there. Your excellent advice is appreciated.

Powermates for photography are too expensive and don't offer the results to match the price tag. Photos taken with them are no better than those taken with a 3 element telenegative from an old telephoto zoom lens which can be had for just a few $.

Paul.

Agree!